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					TECHNICAL SPECIFICATION                         DISNET(RBC NARWAR) SINDH PROJRCT PHASE-II




   GOVERNMENT OF MADHYA PRADESH
                          WATER RESOURCES DEPARTMENT




                          SINDH PROJECT (Phase – II)


               TECHNICAL SPECIFICATION




WATER RESOURCE DEPARTMENT
                                                                                       0
TECHNICAL SPECIFICATION




   GOVERNMENT OF MADHYA PRADESH
                          WATER RESOURCES DEPARTMENT




                          SINDH PROJECT (Phase – II)


THE SPECIFICATIONS CONTAINED UNDER DIFFERENT SECTIONS IN THIS
DOCUMENT ARE FOR GENERAL GUIDANCE. IN CASE OF DISAGREEMENT
BETWEEN THE SPECIFICATION OF THE DEPARTMENT AND STANDARD PRACTICES
BEING FOLLOWED AND/OR SPECIFICATIONS NOT PROVIDED SPECIFICALLY, THEN
RELEVANT SPECIFICATION UNDER INDIAN STANDARDS / IRC PUBLICATIONS/WRD
MADHYA PRADESH SHALL PREVA




                                                                  16
TECHNICAL SPECIFICATION




                                     INDEX


    SECTION -1            EXCAVATION AND EARTHWROK    18-62

    SECTION-2                 CONCRETE WORK          63-143

    SECTION-3                  LINING OF CANAL       144-186

    SECTION-4                  MASONRY WORK          187-352

    SECTION-5               IRON AND STEEL WORK      353-376




                                                               17
TECHNICAL SPECIFICATION




                                                                          SECTION - 1
                                                                     EXCAVATION
                                                                          CONTENTS
        1 GENERAL .......................................................................................................................................................... 51
        2 STANDARD ....................................................................................................................................................... 51
        3 SCOPE: .............................................................................................................................................................. 52
        4 PLANNING: ....................................................................................................................................................... 52
        5 SETTING OUT WORK ..................................................................................................................................... 53
        6 CLEARING, GRUBBING AND PREPARATION OF WORKS AREA: ..................................................... 53
        7 STRIPPING, BENCHING AND FURROWING AND PLOUGHING .......................................................... 54
        8 STRIPPING AND BENCHING UNDER EMBANKMENT ........................................................................... 55
        9 EXCAVATION OF CUTOFF OR PUDDLE TRENCH UNDER CANAL EMBANKMENT ...................... 55
        10............................................................................................................. RECORDING OF CROSS SECTIONS.
         57
        11........................................................................................ CLASSIFICATIONS OF EXCAVATED MATERIAL
         58
        12.............................................................................................................. AUTHORITY FOR CLASSIFICATION
         59
        13....................................................................................................................................................... EXCAVATION
         59
        14..................................................................................................................................................... SLIDES/SLIPS:
         61
        15..........................................................................................................................................OVER EXCAVATION:
         61
        16...................................................................................................................................................... DEWATERING
         61
        17...................................................................................................... DISPOSAL OF EXCAVATED MATERIAL:
         62
        18................................................................................................................ EXCAVATION FOR STRUCTURES:
         63
        19............................................................................................................. CLASSIFICATION OF EXCAVATION:
         63
        20..................................................................................................................... CONSTRUCTION OPERATIONS:
         63
        21................................................................................................................................................ PUBLIC SAFETY:
         65
        22.................................................................................................................... EMBANKMENT CONSTRUCTION
         65
        23............................................................................................................................. GENERAL REQUIREMENTS
         65
        24............................................................................................................................................................. MATERIAL
         66
        25...............................................................PREPARATION OF GROUND SURFACE FOR EMBANKMENT:
         66



                                                                                                                                                                              18
TECHNICAL SPECIFICATION


        26..................................................................................................................................................... COMPACTION:
         67
        27...................................................................................................................................... MOISTURE CONTROL:
         72
        28................................................................................................................................. SPECIAL PRECAUTIONS:
         72
        29.................................................................................................................................................. DOWEL BANKS:
         73
        30 .................................................................................................................... WEATHER CONDITIONS :
         73
        31........................................................................................................................................... DRESSING SLOPES
         73
        32............................................................................................................................ SETTLEMENT ALLOWANCE
         74
        33...................................................................................................................................................... TOE DRAINS :
         74
        34............................................................................................................................................ SURFACE DRAINS:
         74
        35...................................................................................................................................................... SIDE DRAINS:
         75
        36.............................................................................................................. ROAD SURFACES AND PARAPETS
         75
        37...................................................................................................................................................... PROTECTION:
         75
        38........................................................................................................................................ ROADS AND RAMPS:
         75
        39....................................................................................................................................DRY STONE PITCHING :
         75
        40..........................................................................................................DRY PICKED UP BOULDER PITCHING
         76
        41....................................................................................................... DRY QUARRIED BOULDERS PITCHING
         76
        42............................................................................................................................................................ ROCK TOE
         77
        43................................................................................................................................................ BORROW AREAS
         80
        44........................................................................................................... PREPARATION OF BORROW AREAS
         80
        45................................................................................................................... STRIPPING OF BORROW AREAS
         80
        46..................................................................................................................................................... BORROW PITS
         80
        47............................................................................................................................ BORROW AREA WATERING
         81
        48.................................................................ADDITIONAL SPECIFICATIONS FOR CANAL EARTHWORK :
         81
        49............................................................................................................................... DRILLING AND BLASTING
         84



                                                                                                                                                                           19
TECHNICAL SPECIFICATION


        50........................................................................................................................................ USE OF EXPLOSIVES
         85
        51............................................................................................ DISPOSAL OF DETERIORATED EXPLOSIVES
         86
        52........................................................................................................................... PREPARATION OF PRIMERS
         86
        53...................................................................................................................................... CHARGING OF HOLES
         86
        54............................................................................................................................................................. BLASTING
         86
        55..........................................................................................................................................ELECTRICAL FIRING
         87
        56................................................................................................................. PRECAUTIONS AFTER BLASTING
         87
        57.....................................................................................................................................BEFORE COMPACTION
         88
        58..................................................................................................................................... DURING COMPACTION
         89
        59........................................................................................................................................ AFTER COMPACTION
         89
        60............................................................................................................................... FREQUENCY OF TESTING
         89
        61.................................................................................................................................. RECORD AND REPORTS
         90
        62.............................................................................................................................................. FIELD TEST DATA
         90




                                                                                                                                                                            20
TECHNICAL SPECIFICATION



                     SECTION - 1: EXCAVATION
      (EXCAVATION FOR CANAL, STRUCTURES AND OTHER WORKS)
1           GENERAL
1.1         The work to be done under these specifications shall consist of furnishing all tools,
            constructional plant, labour, materials and other things required for excavation in all
            stratas. Conveyance and disposal of the excavated materials, including all leads and
            lifts, temporary work for performance of all the operations connected with the work
            embraced under the contract so as to secure satisfactory quality of work.

1.2         Construction and maintenance of diversions in case diversion of existing
            communication lines, channels, nalla or drains where they were disturbed due to
            excavation of canal and for construction of structures.

2.          STANDARDS
The following listing includes the Bureau of Indian Standards applicable for the Excavation
work
      1.       IS: 4701-1982       Code of practice for Earth work on canal.
      2.       IS:7293-1974        Safety code for working with construction
                                   machinery
      3.       IS:3764-1966        Safety code for excavation work
      4.       IS:1498-1970        Classification and identification of soils for
                                   general Engineering purposes
      5.       IS: 2720(Part.2)-   Method of test for soils part-2, Determination
               1973                of water.content.
      6.       IS 2720 (Part.7)-   Method of test for soils Determination of water content dry
               1980                density
                                   relation using light compaction.
      7.       IS : 2720 (Part.    Method of test for soils. Determination of Dry
               28)-1974            Density of soils in place by sand replacement method
      8.       IS:         2720    Method of test for soils (part. 29). Determination of dry density
               (Part.29)-1976      of soils in
                                   place by core cutter method
      9.       IS :1888-1982       Method of load test on soils
      10.      IS:2131-1981        Methods of standard penetration test for soils.
      11.      IS:    4332-1967    Methods of test for stabilized soils methods of sampling and
               (part.1)            preparation of stabilized soils for testing
      12.      IS:    2720-1983    Method of test for soils-Grain size Analysis
               (Part.4)
      13.      IS:    2720-1985    Method of test for soils for. Determination of liquid a plastic
               (part.5)            limits.
      14.      IS:    2720-1971    Determination of dry Density moisture content-relation by
               (Part.9)            constant weight of soils method.
      15.      IS:    2720-1991    Determination of unconfined compressive Strength
               (Part.10)
      16.      IS:    2720-1986    Method of test for soils.(Part.13)direct shear test.
               (part.13)
      17.      IS:2720-1986        Method of test for soils: (Part.15) Determination of
               (part.15)           consolidation properties.
      18.      IS2720-1983         Method of test for soils for. Determination of Density Index,
               (part.14)           (relative density) of cohesion less soils.



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TECHNICAL SPECIFICATION



      19.      IS:2720-1987        Method of test for soils Laboratory determination of C.B.R
               (part.16)
      20.      IS:2720-1964        Method of test for soils. Determination of field moisture
               (part.18)           equivalent
      21.      IS: 2720-1977       Method of test for soils.
                                                   (part. 40)            Determination of free
                                   swell index of soils.
      22.      IS:2720-1977        Method of test for soils. Determination of swelling pressure of
               (part.41)           soils
      23.      IS: 8237-1985       Code of practice for protection of slopes for reservoir
                                   embankment

3.          SCOPE:
Excavation of canal/channel/approach channel/drain/cut off trench/key trench /toe wall/toe
drain/foundations for structures/Cut off wall/chute drains etc., in all soils/disintegrated
rock/Shale/H.R. in both wet and dry conditions and disposal of soil not useful for
construction, on spoil bank and stacking of useful stone, disposal of not useful stone,
conveyance of excavated spoil/soils including swell, conveyance of excavated rock including
voids, with all leads, lifts and delifts and formation of spoil bank/stock piles, including
dewatering, diversion of streams, formation and removal of ramps, diversion roads/approach
roads, shoring/strutting. etc., as directed by the Engineer-in-charge to complete the finished
item of work.

4.          PLANNING:
4.1         Prior to the commencement of work, all relevant data shall be collected by the
            contractor and drawings prepared by him showing the location of the excavation,
            spoils, deposition and filling. On these drawings, full cutting reaches, partial cutting
            and partial embankment reaches and full embankment reaches should be distinctly
            indicated. The quantity of material to be placed in fill shall be noted clearly in these
            reaches. Where the material to be excavated. consists of different types and if the
            various types have to be used separately in the fill or dumped to spoil bank, the
            quantities of each class of material in each area should be shown on drawings.

4.2         The contractor shall present his planning of the work along with required details to
            the Executive Engineer at least 15 days before starting the work.

5.          SETTING OUT WORK
5.1         Bench Marks : Before starting any work, a permanent bench mark, reference line
            and check profiles at convenient positions approved by the Engineer-in-Charge shall
            be erected. The bench marks shall be as per type design 6 and 8 of Department. The
            works “B.M.” with R.L. shall be conspicuously carved and painted on the bench mark.
            The reference line shall comprise of a base line properly dag belled on the ground
            with number of masonry pillar. The check profiles, shall be of such materials and
            shall be located at such places as to ensure execution of all slopes, steps and
            excavation to the profile or profiles indicated in the approved drawings or as directed
            by the Engineer-in-Charge.

5.2         The Sub-Divisional Officer on behalf of the Engineer-in-Charge shall himself layout
            all important levels, all control points with respect to this bench mark and reference
            line and correlate all levels and locations with this bench mark and the reference line.
            Important levels shall be checked by the Executive Engineer. All assistance shall be
            given for the same by the agency executing the work.


                                                                                                 22
TECHNICAL SPECIFICATION



         In the case of spread out works, several bench marks, reference lines and check
         profiles may be necessary and shall be constructed as directed by the Engineer-in-
         Charge.

5.3      Except the mathematical and surveying instrument which shall be provided by the
         department, all materials and labour for setting out works including construction of
         bench marks, reference lines, check profiles and survey required for setting out
         works as may be required at the various stages of the construction works, shall be
         supplied or made by the agency executing the work.

6        CLEARING, GRUBBING AND PREPARATION OF WORKS
         AREA:
        (i) All excavation areas and dam embankment are including a 6 m wide strip
            measured beyond and contiguous to the limit line of the area as shown on the
            drawing shall be cleared and any roots etc. completely removed as specified. All
            trees, down timbers, fencing bush, rubbish, other objectionable materials and
            vegetation shall be cleared. All stumps and roots shall be excavated and removed.
            All roots over 50 mm in diameter shall be removed to a depth of 90 cm below the
            original ground surface or as directed by the Engineer-in-Charge. Materials thus
            removed will be burnt or completely removed from the site. All felled timber and fuel
            shall be properly stacked and handed over to the department, when asked for by
            the Engineer-in-Charge. Piling for burning shall be done in such a manner and in
            such location as to cause the least fire risk. All burning shall be thorough so that
            the materials are reduced to ashes. Special precautions shall be taken to prevent
            fire from spreading to the areas beyond limits of the areas specified and suitable
            equipment and supplies for preventing and suppressing fire shall be available at all
            time.
        (ii) No trees shall be cut from outside of areas designated unless instructed in writing
             by the Engineer-in-Charge and all trees designated outside of the areas actually
             occupied by the works shall be protected carefully from the damage.

7.       STRIPPING, BENCHING AND FURROWING AND PLOUGHING
7.1      The ground surface under all canal embankment excepting rock surface, where it is
         below full supply level in the canal, shall be stripped, benched or furrowed and
         ploughed as per guidelines given below if not specified otherwise.
7.1.1    Benching : Benching should be provided only where the work is to done on highly
         undulating stiff ground, steeply sloping ground or on existing canal embankments.
         Benching shall consist of excavation of triangular trenches with a slope of 1 in 12 with
         average depth of cutting as 15 cms longitudinally below the embankment seat or in
         the form of steps with height of steps not more than 30 cms. The slope of trenches
         shall be towards the centre from the outer toes of the embankment.
7.1.2    Stripping and Ploughing and Furrowing : Recommended treatment on embankment
         seat for stripping and ploughing and furrowing under different situation should be as
         below :-




                                                                                              23
TECHNICAL SPECIFICATION



           Type of                               Depth of stripping for
          vegetable
                              Q < 3.0 Cumecs                             Q > 3.0 cumecs
         Growth on         H > 1.5 m    H< 1.5 m        H > 0.6 m     H < 0.6 m    H > 3.0 m
           the soil
            1. Soil          8 cms        Nil only       15 cms         Nil only       15 cms
         containing a                    ploughing                     ploughing
         grass cover                        and                           and
                                         furrowing                     furrowing
               2.          Upto depth     -- do --       15 cms         -- do --     Up to dept
          Agricultural    of ploughing                                                   of
             land            but not                                                 ploughing
                           exceeding                                                  but not
                            15 cms.                                                  exceeding
                                                                                      15 cms.
Note1: Where FSL in the channel is below the ground level, neither stripping, nor ploughing
       and furrowing shall be done.
Note2:None of the treatments described in the above table shall be done for seat under spoil
      banks.
Note3: Where the depth of stripping needed is more than 15 cms, it shall be carried out only
       after approval by the Engineer-in-Charge.
         The foundation for canal embankments shall be prepared in accordance with para
         4.9.2(a) to (c) depending upon the nature of foundation materials.
7.1.3    Disposal of Materials : In all the items of benching / stripping and preparation of base
         on rocky strata, described in para 7.1.1, 7.1.2 above, the material from excavation,
         shall be deposited in specified areas in a manner as may be directed by the
         Engineer-in-Charge and in such a way as not to detract from the finished appearance
         of the work.
         a) All the stripped material shall be deposited beyond the catch drain at the
            rear toe of embankment.

8.       STRIPPING AND BENCHING UNDER EMBANKMENT
8.1      The entire area of embankment including a 3 m wide strip beyond and contiguous
         with the area of embankment proper as shown in the drawing shall be stripped or
         benched to a sufficient depth as directed to removed all unsuitable materials. The
         unsuitable material to be removed shall include loose rock, vegetation, top soil, sod,
         organic silt, swamp material and rubbish and any other objectionable materials below
         the ground surface.

8.2      At locations where a river or stream crosses the embankment site, loose sand and
         gravel and loose boulders shall also be removed as directed.

8.3      Stripped materials shall be disposed off in a manner as may be directed by the
         Engineer-in-Charge and in such a way as not to detract from the finished appearance
         of the project.




                                                                                              24
TECHNICAL SPECIFICATION



9.       EXCAVATION OF CUTOFF OR PUDDLE TRENCH UNDER
         CANAL EMBANKMENT
9.1 Procedure for excavation :

9.2      A cut off trench or puddle trench as shown in the drawings shall be excavated in the
         foundation of the dam at the location indicated. This trench shall excavated to a
         depth of 0.6 m to 1.2 m into rock (depending upon the permeability of the rock) or
         into other impervious stratum as may be approved by the Engineer-in-Charge.
         Accurate trimming of the slopes of the excavation will not be required but the cutting
         in general shall follow lines as specified in drawings. The area to be excavated shall
         be unwatered. The water level shall be maintained below the level of excavation in
         the area and none of the excavation shall be performed in standing water.

9.3      Utilisation of Excavated Materials :

9.4      Trench excavation shall preferably be started after the whole base of the dam or
         atleast the substantial part of its is cleared, grubbed, benched or stripped as required
         by specifications so that suitable material out of trench excavation can be directly
         utilized for forming the bank, to maximum possible extent.

9.5      Blasting of Rock :

9.6      No blasting of rock would be permitted for the excavation in hard rock, when the
         excavation reaches within about 60 cm of final levels, if the opinion of the Engineer-
         in-Charge such blasting will shatter and disturb the rock below foundation. He may
         also put similar restrictions in cases where damage is apprehended to works in
         neighboring area existing or under construction. In such cases rock excavation shall
         be completed by chiseling and wedging etc.

9.7      Material Received from Cut off Trench or Puddle Trench :

9.8      The materials, excavated from the trench shall, if suitable, be used in the
         embankment either immediately or after stock piling as convenient and directed by
         the Engineer-in-Charge. The suitability or otherwise of the material and zone of the
         embankment in which it is to be placed will be specified by the Engineer-in-Charge
         on the basis of laboratory tests.

9.9      Material excavated from the trench shall not be placed in the embankment till
         foundation for the embankment has been cleared, stripped and prepared as specified
         and adequate arrangements made for watering and rolling the layers of earth fill in
         the embankment.

9.10     Materials excavated from the trench shall be subjected to the same degree of
         embankment control as material obtained from borrow pits.

9.11     The material excavated from the trench which are not suitable for use in the
         embankment shall be disposed off in a manner as may be directed by the Engineer-
         in-Charge and in such a way as not to detract from the finished appearance of the
         project.

9.12     Cut off Trench Filling :

9.13     Cutoff trench shall be back filled with impervious material of the same specification
         and in the same manner as for the impervious hearting zone of the embankment of


                                                                                              25
TECHNICAL SPECIFICATION



         the dam in accordance with specifications under para 4.9. But before back filling is
         started foundation grouting in accordance with specifications of chapter 22 may be
         completed, where required, unless the Engineer-in-Charge directs otherwise.

9.14     Puddle Filling :

9.15     Puddle :

9.16     The puddle shall consist of good retentive clay of best quality free from organic or
         other foreign material. It should be clean and tough and should be available near the
         site as far as possible. The most suitable clay is of the description used for tile
         making. Soft sludgy, peaty, sandy, salt or puffy clay should be rejected.

9.17     The clay is to be worked out into puddle before use by turning it over and over again
         with phowras, watering and treading with men’s feet into one plastic homogeneous
         mass of the toughest consistency until it gets plasticity.

9.18     Laying of Puddle :

9.19     The puddle shall then be made into balls and thrown into the trench or in any other
         position required. No more than 15 cm in thickness of puddle shall be deposited in
         the place at one time and it must at once be thoroughly kneaded by men’s feet and
         incorporated with mass below it so that the whole will be uniform and not in layers.

9.20     The top of puddle shall be kept as level and uniform as possible and shall on no
         account be allowed to dry. If the surface cracks at any time it shall be dug up and
         puddle remade.

9.21     Vertical joints across the puddle wall and steps to its side shall be avoided. All joints
         shall be made by long inclined faces over lapping each other.

9.22     The whole width of puddle trench excavated shall be filled with puddle only so that
         the puddle gets thoroughly into the interstices of trench walls. The joint near the wall
         shall be thoroughly kneaded with men’s hels.

9.23     On holidays and other days, when works are stopped, labour should be specially
         employed to keep the surface of puddle wet by sprinkling of water.

9.24     The puddle filling shall not be done in standing water. Water level in trench shall be
         kept below the working level by means of pumps, if required.

9.25     As the surface of the puddle layer dries up, it should be thoroughly consolidated with
         rammers. Before a new layer of puddle is laid the surface of the previous layer, if not
         newly made, should be lightly sprinkled with water by means of watering pots and
         kneaded.

9.26     When puddle is finished, it should be immediately covered up in the work or when
         this is not possible, it should be lightly sprinkled with water by means of watering pots
         and kneaded.

9.27     The surface soil if not confirming to approved hearting soil, is to be removed on both
         sides of the puddle trench for a breadth equal to that of the top of the trench, and for
         0.60 m deep, and consolidated in the same way.




                                                                                               26
TECHNICAL SPECIFICATION



9.28     This filling is to be carried up with the puddle wall to a height of 0.6 m above ground
         level and joined with the hearting.

10       RECORDING OF CROSS SECTIONS.
10.1     Immediately prior to the beginning of the work, cross-sections of the existing ground
         level at suitable intervals, normal to the axis of canal, and other channels, sluice,
         waste-weir or other masonry structures, etc. shall be taken over the base and seating
         of the Channels or other structures, etc. for sufficient distance outside the limits.
         Levels on these cross-sections shall be taken at suitable interval not exceeding 6 m
         or as directed by the Engineer-in-Charge.

10.2     These cross-sections shall be taken and plotted in ink on graph Measurement Book
         by the construction agency and checked by consultant agency Departmental Officer
         Incharge of work shall check there level as required These cross-sections shall form
         the basis of all future measurements.

10.3     After clearing the area required for canal excavation and construction of
         embankments, cross sections shall be taken at every 30M interval or closer,
         depending on the nature of ground, normal to axis of canal upto sufficient distance
         outside the limits of the work. Levels on cross sections shall be at 6M. intervals or
         closer intervals as directed by the Engineer -in-charge and entered in level field
         books and cross sections will be plotted in graph M.B. The contractor shall write a
         certificate. Accepted the measurements               recorded on pages from
         ________________to ______________ and sign at the end of levels in the graph
         M.B. in token of acceptance.

10.4     After stripping and prior to commencement of excavation cross sectional levels of
         stripped surface shall be taken at the same locations at intervals as specified in para
         (a) above and certified as mentioned shall be recorded by the contractor.

10.5     At the earliest, cross sectional profiles shall be prepared by the contractor duly
         plotting the pre-levels and the contractor’s signature shall be obtained on these
         cross-section sheets plotted in graph M.B. The cross sections called initial cross
         section taken after striping shall form the basis of all future measurements. These
         initial cross sections duly signed by the contractor and Engineer-in-Charge shall be
         preserved. All linear dimensions shall be measured in meters to the nearest 0.01
         meter, volumes worked out in cubic meters corrected to 0.01 cubic meter. However,
         in case of rock excavation occurring in bed or sides, the actual quantity of rock shall
         be arrived by taking block levels at 2.5M. intervals all along the entire area of bed
         and sides.

11       CLASSIFICATIONS OF EXCAVATED MATERIAL
11.1     All materials involved in excavation shall be classified into the following groups.
Soft or Ordinary Soil
Generally any soil which yields to the ordinary application of pick and shovel or to spade,
rake or other digging implement, such as vegetable or organic soil, turf, gravel, sand, silt,
loam, clay peat, etc.
Hard Soil
Includes all materials which can be removed with shovel or spade after lossening with pick
axe such as clay soil mixed with lime kankar, black cotton soil for earthen bund, soft
moorum, etc.


                                                                                               27
TECHNICAL SPECIFICATION



Hard Moorum and Moorum Mixed with Boulders
Generally any material which requires the close application of picks, jumpers or scarifiers to
loosen such as hard and compact moorum and soft shale. Moorum or soil mixed with small
boulders not exceeding 25% in quantity and each less than 0.014 cum (300 mm dia) but
more than 0.004 cum in size.
Note : Boulder is rock fragment usually rounded by weathering, disintegration or exfoliation
or abrasion by water or ice, found lying loose on the surface or embedded in river bed, soil
talus, slope wash and terrace material of dissimilar origin.
Disintegrated Rock
Includes such strata which requires the close application of crow bars, picks, grafting tools,
scarifiers in suitable combination for its excavation such as soft laterite, soft conglomerate,
hard shale, soft copra, hard and compact moorum mixed with small boulders exceeding 25%
in quantity but each not exceeding 0.014 cubic metre in size.
Soft Rock
Soft Rock comprises of the following:-
         (i)       Boulders (not greater than 0.5 cum in volume), hard laterite, hard copra and
                   hard conglomerate or other rock which may be quarried or split with crowbars,
                   with casual blasting, if required, for loosening of strata.
         (ii)      Any rock which in dry state may be hard, requiring blasting, but when wet
                   becomes soft and manageable by means other than blasting.
Hard Rock (Requiring blasting)
Any rock or boulder (More than 0.5 cum in volume) which requires the use of mechanical
plant or blasting for excavation or splitting.
Hard Rock (blasting prohibited)
Hard rock requiring blasting as described as above but where blasting is prohibited for any
reason and excavation has to be carried out by chiseling, wedging or any other agreed
method.

12       AUTHORITY FOR CLASSIFICATION
The classification shall be decided by the Engineer-in-Charge and his decision shall be final.

13       EXCAVATION
      a)        Where sub soil water is expected the excavation shall be started preferably from
                the nearest valley.
      b)        The contractor shall commence excavation immediately after the surface area of
                ground is prepared.
      c)        The Government reserves the right, during the progress of work to vary the slope
                of excavation or the slope of embankment and the dimensions depended
                thereon.
      d)        Suitable arrangements for drainage shall be provided to take surface water clear
                of excavation during the progress of work. Sump pits if found necessary shall be
                excavated at suitable places and the water thus collected shall be bailed out or let
                into a near by valley at his cost. When cutting on cross sloping ground, the
                contractor shall cut a catch water drain on the higher side to prevent water from
                flowing down the cutting slope. No separate payment shall be made for this work
                unless otherwise specified.



                                                                                                 28
TECHNICAL SPECIFICATION



      e)     No distinction shall be made as to whether the material being excavated is wet or
             dry or in water.
      f)      All washable materials and any soil, which generally becomes unstable on
             saturation such as organic soil, loose soils and expansive soils, shall be removed
             as directed by the Engineer-in-charge.
      g)     All Suitable excavated material within economic lead shall be used for
             construction of embankments.
      h)     Stones of more than 75 mm. in size and indurate materials shall be removed from
             material to be used for compacted embankments.
      i)     In soils the contractor shall not excavate out side the slopes or below the
             established grades or loosen any material outside the limits of excavation. Any
             excess depth excavated below the specified levels shall be made good at the
             cost of the contractor to standards as prescribed by the Engineer-in-charge.
      j)     The method of drilling and blasting to be resorted to the excavation in rock shall
             be in accordance with specification “Drilling and Blasting” and got approved by
             the Engineer-in-Charge.
      k)      Above the lining, in case of lined canals and above the proposed water level in case
             of unlined canals, the rock may be allowed to stand at its safe angle and no finishing
             is required other than removal of rock masses which are loose and are liable to fall.
      l)      Except in areas of rock, all areas to be excavated shall be pre-wetted so that at the
             time of excavation moisture content will be at about optimum. However, in case of the
             spoils to be deposited on spoil banks such pre-wetting need not be done.
      m)     During rock excavation, the contractor will not be allowed to dispose of the rubble
             Surplus usable rubble shall be allowed to be used in construction of rock-toe,
             masonry works and for crushing to use as metal in concrete works etc., crushed sand
             cost subject to approval of the Engineer-in-Charge. The Contractor may use the
             excavated useful soils, stone, and other construction material free of cost for
             construction purpose on this project only and the rates quoted shall include such
             utilization.
      n)     The re-gradation for tail channel and approach channel for structures and diversion of
             drains or nalla shall conform to the lines, dimensions, grades, side slopes, and levels
             and shown on drawings or as directed by the Engineer-in-charge.
      o)     Where suitable materials in excess of that required to construct adjacent
             embankments or in deficit sections by conveyance or back filling of structures or to
             construct O&M. Road, Ramps and Bridge approach embankments as determined by
             the Engineer-in-charge in one continuous operation, then such material shall be stock
             piled at places designated by the Engineer-in-Charge for later use.
      p)     All gangways, roads and stopping shall be such that they fall within the cross sections
             so that the final dressing of slope will consist of digging and no rolling will be required.
      q)     During rock excavations, over-hangs or unsafe slopes shall not be permitted.
      r)     Unless otherwise specified, over excavation in rocks/soils shall not be permitted.
      s)     Blasting in a manner as to produce over -breakage which in the opinion of Executive
             Engineer is excessive shall not be permitted. Special care shall be taken to prevent
             over breakages or loosening of material on bottom and side slopes against which
             lining is to be placed.
      t)     Final cutting for 300 mm. in rock shall be carried out by controlled blasting or
             trimming or by chiseling wedging, barring with the help of pneumatic paving breakers
             and no extra payment will be made.




                                                                                                      29
TECHNICAL SPECIFICATION



       u)      In the case of Fissured rock and hard rock pre-measurements shall be taken. The
               contractor shall before commencing the excavation in rock etc., expose the surface.
               The pre-measurements shall be taken by taking levels at 2.5M. intervals both ways
               which forms the basis for payment of excavation for rocks. Where the rock is
               intermingled with ordinary soils contained pre-measurements of soils shall be taken
               and measurement of soils shall be obtained after deducting from the contained
               measurements, the quantity of the boulders etc. which will have to be disposed as
               per direction of Engineer-in-Charge.
       v)      In the case of boulders they should be marked by tar-pre measurements recorded.
               After removal and disposal as directed by the Executive Engineer or his subordinates
       w)      In case of reservoir/tank works, the useful materials excavated in the cut of trenches
               key trenches approach channels from the sluices, over burden removal on the U/S
               and D/S sides of surplus weir, and foundations, excavation for sluices and surplus
               weir, excavated shall be used for construction purposes. Any material unsuitable for
               construction purposes shall be disposed of as directed by the Engineer-in-charge.

14          SLIDES/SLIPS:
14.1        If slides occur in cutting during the process of excavation they shall be removed by
            the contractor at his cost as directed by the Engineer -in-charge.

14.2        If finished slope slide into the canal subsequently such slips in rock shall be removed.

15          OVER EXCAVATION:
15.1        In soils any excess depth below the specified levels and any excess excavation in
            slopes and widths shall be made good at the cost of the contractor with suitable soils
            of similar characteristics and compacted to a density not less than 95% of proctor’s
            density.

15.2        In the canal section where expansive type of soil such as C.H. type of soil is
            encountered and over which cement concrete lining directly be laid, the canal prism
            shall be over excavated to the extents as directed by the Engineer-in-charge and
            such over excavated section shall be filled with suitable cohesive non-swelling
            (CNS)type soil and shall be placed in uniform horizontal layers and compacted as
            directed by the Engineer-in-charge. The over excavation made in such strata filling
            by suitable soil locating and compacting of such soil will not be paid separately.

16          DEWATERING
16.1        If water is met in the excavation due to sub-soil ground water, springs, seepage, rain
            or other causes, it shall be removed by suitable diversion, pumping or bailing out and
            the sub-soil water table shall be kept below the excavation so that the excavation
            kept dry whenever so required as directed by the Engineer-in-charge care shall be
            taken to discharge the drained water as not to cause damage to the works, crops or
            any other property. In case of lined canals, the subsoil water shall not be allowed to
            accumulate in the bottom of the canal. The bed/sides shall be moisture to receive
            lining as directed by the Engineer-in-charge. No separate payment will be made for
            dewatering.

16.2        Where water is met with in excavation due to stream flow, seepage, rain or other
            reasons, the contractor shall take adequate measures such as bailing, pumping,
            construction of diversion channels, drainage channels, bunds, cofferdams and other
            necessary works keep the foundation trenches dry when so required and to protect


                                                                                                  30
TECHNICAL SPECIFICATION



         the green concrete/ masonry against damage by erosion or sudden rising of water
         level. The methods to be adopted in this regard and other details there of shall be left
         to the choice of the contractor but subject to approval of the Engineer-in-charge.

16.3     Approval of the Engineer-in-charge shall however shall not relieve the contractor of
         the responsibility for the adequacy of dewatering and protection arrangements and
         for the quality and safety of the works.

16.4     The Contractor shall take all precautions in diverting the channels and discharging
         the drained water as not to cause damage to the works, crops or any other property.

16.5     Pumping from the interior of a foundation shall be done in such a manner as to
         preclude the possibility of the movement of water through any fresh concrete. No.
         Pumping shall be permitted during the placing of concrete or for any period of atleast
         24 hours thereafter, unless it is done from a suitable sump separated from the
         concrete works by water tight wall or other similar means.

17 DISPOSAL OF EXCAVATED MATERIAL:
       (a)   No rehandling of excavated material due to injudicious selection of place for
             dumping will be paid for.
       (b)   Material removed in excavation including stripped top soil and expansive soils not
             required for embankments, bank fill or other required earth work shall be
             deposited in waste banks on right of way owned by or controlled by the
             department as directed by the Engineer-in-Charge. A gap of 3 M wide shall be left
             in spoil banks at 150 m intervals or as directed by Engineer-in-Charge for
             disposal of drainage in accordance with clause 8.20 of IS : 4701-1982.
       (c)   Minimum gap of 1 meter or ½ m the depth of excavation as per drawing
             (whichever is more) from the edge of the excavation at G.L. in cutting reaches
             and 1 m gap from the outer toe of the embankment to the inner toe of the spoil
             bank or a greater distance as prescribed by the Engineer-in-Charge shall be
             maintained.
       (d)   Where the canal is aligned on sloping ground, excavated material not required for
             construction of adjacent embankments at any other place, shall be deposited on
             the lower side. Where canal is on level or nearly level ground, the material from
             excavation shall be deposited on embankments on both sides of the canals.
       (e)   In case of deep cutting the spoil shall be so disposed off as not to result in
             unsightly heaps as shall be leveled and properly dressed. The top of both the
             finished banks shall slope away from the inner edge with a suitable gradient.
       (f)   If there is excess of useful material from the excavation than needed for
             construction embankments of canal/reservoir/tank, it shall be used to strengthen
             the embankment on either side of the canal/reservoir/tank, deposited in low areas
             uphill of the canal to eliminate trap drainage, or it should be deposited in stock
             piles as directed by the Engineer-in-Charge. The disposal of excavated material
             shall be in accordance with clauses 8.1 of IS 4701-1982.
       (g)   The useful rock obtained from the cutting shall not be mixed with other soils and
             shall be closely stacked to the gauge separately beyond spoil bank and all other
             stone not useful for construction purpose shall be deposited on the slopes of the
             canal spoil bank, if the rock and soil are mixed up while depositing at the spoil
             banks, suitable deduction from the agreement rate as decided by the Engineer-
             in-Charge will made which is binding on the contractor.




                                                                                              31
TECHNICAL SPECIFICATION



       (h)   Except as specially provided in these specifications for payment for conveying or
             placing of individual items of excavated materials.
       (i)   The contractor has no claim over any of the materials got out of excavation of the
             canal cutting and foundation excavation.
       (j)   The responsibility for arranging the land required for disposal of excavated
             material rest with contractor, if the contractor desires the material at near by
             places other than the places shown by the Engineer-in-charge, to reduce the lead
             and there by the cost of conveyance.

18 EXCAVATION FOR STRUCTURES:
18.1     Description of work:
          a) Excavation and depositing the soil on spoil bank or at any place specified by the
       Engineer-in-charge with all leads lifts for structures shall consist of the removal of
       material for the construction of foundations for the structures like Bridges, U.Ts.
       Aqueducts, super-passages, retaining walls, canal side walls, in lets, out lets, head
       walls, cutoff walls, pipe under-tunnels, cross regulators, off-take sluices and other
       similar structures, in accordance with the requirements of these specifications and the
       lines elevations and dimensions shown on the drawings or as indicated by the
       Engineer-in-charge.
       b) The work shall include providing all the materials, tools and plants and labour
       required for presplitting and utilising controlled blasting technique over and above the
       normal blasting technique in hard rock and quartzite excavation, construction of the
       necessary coffer dams and cribs and their subsequent removal and necessary
       sheeting, shorting, strutting, benching, draining and pumping the foundations, trimming
       bottom of excavations, all leads and all lifts of excavated material back filling with
       selected approved material and clearing up the site and the disposal of all surplus
       materials, spoil and the stone not useful for construction purpose shall be deposited
       beyond the profile of the structure, canal, stream etc., leaving a minimum gap of 5
       meters. and in accordance with clause 8.1of IS 4701-1982 or at greater distance as
       directed by the Engineer-in-charge. The useful stone stacking and soils required for
       back filling shall be placed at the contractors convenience without forgoing the working
       space. No rehandling of materials, will be paid and at the same time recovery will be
       made if the obstructions are not removed after completion of the work from the final
       bill at the rate calculated by the Engineer-in-charge to do the same work with other
       agency. In so far as practicable, the material removed in excavation for structures shall
       be used for back filling and embankments.

19       CLASSIFICATION OF EXCAVATION:
19.1     All materials involved in excavation shall be classified in accordance with Clause
         no.13

20 CONSTRUCTION OPERATIONS:
       (a)        Setting-out
                  After the site has been cleared to the limits of excavation the workshall be set
                  out true to lines, curves, and slopes as shown on plans.
       ii)        Excavation:
                  (a)     Excavation shall be taken to the width of the lowest step of the footing
                          and the sides shall be left to plumb where the nature of soil allows it.



                                                                                               32
TECHNICAL SPECIFICATION



                          Where the nature of soil or the depth of the trench does not permit
                          vertical sides, the contractor at his own expense shall put up
                          necessary shoring, strutting and planking or cut slopes to a safer
                          angle or both with due regard to the safety of personnel and works
                          and to the satisfaction of the Engineer-in-charge.
                  (b)     The depth to which the excavation is to be carried out shall be as
                          shown on the drawings, unless the type of material encountered is
                          such as to require changes in which case the depth shall be as
                          ordered by the Engineer-in-charge and will be paid for.


                  (c)     Excavation in rock shall be carried out by crow bars, pickaxes, chisels
                          of pneumatic drills etc. unless permitted by Engineer-in-charge
                          blasting shall not be resorted to.
                  (d)     Where blasting is to be resorted to the same shall be carried out to the
                          requirements of specification 3.3and all precautions there in observed.
                  (e)     No distinction shall be made as to whether the material being
                          excavated is dry or moist or in water.
           The method of drilling and blasting to be adopted for hard rock including F&F rock
           excavation shall be approved by the Engineer-in-charge. Blasting in a manner as to
           produce over breakage which in the opinion of Engineer-in-charge is excessive
           shall not be done. In order to minimise over breakage and loosening of material at
           the finished surface on bottom and side slopes over which foundation concrete is to
           be laid, final cutting for the last 300mm. in hard rock shall be carried out by
           controlled blasting or chiseling or trimming with the help of pneumatic paying
           breakers. If excavation is required to be done within 30m. from the existing
           structures the same should be carried out by chiseling without resorting to blasting
           for which no extra rate is payable.

20.1     PREPARATION OF FOUNDATION:

20.2     The contractor shall prepare firm foundation for the structure as shown in the
         drawings. The bottom and side slopes of foundation upon or against which the
         structure is to be placed shall be finished to the prescribed levels and dimensions
         shown on plans.

20.3     The bottom of the foundation shall be leveled both longitudinally and transversely or
         stepped as directed by Engineer-in-charge. Before foundation concrete is laid, the
         surface shall be slightly watered and rammed. In the event of excavation having been
         made deeper than that shown on the drawings the extra depth shall be made up with
         concrete or masonry of the foundation grade at the cost of the contractor as directed
         by the Engineer-in-charge. Ordinarily earth filling shall not be used for the purpose to
         bring the foundation level. If hard strata is not met at foundation level shown in the
         drawings extra depth as directed by Engineer-in-charge shall be excavated to
         remove unsuitable material. The extra excavation or extra depth made up with
         masonry or concrete will not be paid.

20.4     When rock or other hard strata is encountered, it shall be free from all soft and loose
         material, cleaned and cut to a firm surface either level, stepped, or serrated/notched,
         as directed by the Engineer-in-charge. All seams shall be cleaned out and filled with
         cement mortar or grout to the satisfaction of the Engineer-in-charge.




                                                                                               33
TECHNICAL SPECIFICATION



20.5     If it is considered necessary by the Engineer-in-charge, to consolidate the foundation
         strata by grouting cement slurry, the drilling and grouting or any other foundation
         treatment as directed by the Engineer-in-charge shall be done by the contractor

21       PUBLIC SAFETY:
21.1     Nearest, towns, villages and all required places, trenches and foundation pits shall be
         securely fenced, provided with proper caution signs and marked with red lights at
         night to avoid accidents. The contractor shall take adequate protective measures to
         see that the excavation operations do not effect or damage adjoining structures or
         property.

22       EMBANKMENT CONSTRUCTION
22.1     SCOPE:

22.2     Site clearance, stripping and formation of embankment of homogeneous
         section/zonal section viz., casing zone/hearting zone with the useful excavated soils
         and balance soils of approved quality from the borrow area including the cost of soil,
         if any sampling, testing and pre-wetting of soils at source of excavation and
         conveyance of soil and extra soils required for shrinkage including swell factor with
         all leads, lifts, delifts, laying on bank, spreading, breaking clods, sectioning, extra
         watering and consolidation including benching of old embankment slopes, joining
         with the new embankment formation,            trimming of side slopes, formation and
         removal of ramps, formation of Dowel banks etc., as per drawing and as directed by
         the Engineer -in-charge to complete the finished item of work.

23       GENERAL REQUIREMENTS
23.1     The Cross sections for embankment are to be designed to suit the characteristics of
         the best quality soils available in the vicinity of the proposed work. If the contractor
         proposes to use any other type of soils than those mentioned in the design to save
         the lead and thereby the cost, the contractor has to form the embankment to the
         revised profiles worked out by the competent authority. The extra quantity involved
         will not be measured and paid. The theoretical quantity required based on the original
         cross-sections will only be measured and paid. But the Contractor has to form the
         bund to the revised cross section designed with the characteristics of the proposed
         soils. The designs given by the estimate sanctioning authority are final.

23.2     Embankment shall be built to the height, top width and side slopes as shown on the
         drawings. All the edges of the embankment shall be neatly aligned symmetrical to the
         central line. They shall be absolutely straight in all reaches except at bends. At bends
         they shall be smoothly curved.

23.3     The top of each embankment shall be leveled and finished so as to be suitable for
         road way and given a cross slope to drain away rain water. The bank carrying road
         shall be given a suitable cross slope.

24       MATERIAL
24.1     The suitability of foundation of placing embankment materials thereon and all
         materials proposed for use in construction of embankment shall be determined by the
         Contractor well in advance on the basis of Laboratory Test results. Chemical and
         Physical tests of the material proposed for construction of embankment shall be



                                                                                              34
TECHNICAL SPECIFICATION



         carried out to ensure that the soil does not contain soluble lime content, soluble lime
         salt content or cohesion less fines, in quantities harmful to the embankments.

24.2     Material for construction of embankment should be free from the organic material.
         Unless otherwise directed by the Superintending Engineer/ Executive Engineer all
         materials shall be deposited in embankments so that cobbles, gravel and boulders
         are well distributed through other material and not nested in any portion within or
         under are embankment as per clause 6.4 of I.S. 4701-1982.

24.3     Suitable excavated material available from the cut off trenches, canal cutting, extra
         cutting for seating to lining, foundation excavation for structures, approach and tail
         channels for structures, nalla diversions, removal of ramps etc, shall be used for
         construction of adjacent embankments.

24.4     After completing the construction of embankments with the materials as indicated in
         37.3 above, material required for the construction of balance embankment shall be
         obtained from the borrow areas.

24.5     The soils and morum excavated and useful for construction of the embankment shall
         be classified by the Engineer-in-Charge as impervious and Semi-Pervious based on
         Laboratory Test results. They shall be utilized on the embankment work.

25       PREPARATION OF GROUND SURFACE FOR EMBANKMENT:
25.1     Clearing site : Clause 6 shall apply.

25.2     Stripping : Clause 77 shall apply.

25.3     All portions of excavation made for test pits or other subsurface investigations, all
         holes, hollows and all other existing cavities found within the area to be covered and
         to the extent below the established lines of excavation for embankment seat shall be
         filled in earth of the corresponding zone of the embankment and suitably compacted.
         The pits of surface boulders shall be filled with suitable material and compacted at no
         extra cost.

25.4     Pools of water shall not be permitted in the foundation for embankment and such
         water shall be drained and cleared prior to placing the first layer of embankment
         materials.

25.5     On sloping ground or in case of existing banks, where embankment portions are to
         be modified, benching of slopes shall be done with a little slope towards the inside of
         beaching so as to give a good grip to the embankment soil with the sub-grade.
         Unless otherwise specified the benches shall be 0.3.X.0.6.m. on the front and rear
         slope of the embankment. Before benching, the bank slopes shall be cleared of all
         roots and vegetables matter as per specification 2.0. No separate payment will be
         made for either benching or refilling. The rate quoted for raising embankment is
         inclusive of above operations. The bank section shall be brought to design standards
         by filling the scours with suitable material and compacting to 98% proctor density by
         suitable measure of compaction.

25.6     Soil foundation:

25.7     The ground surface under embankment and area of bed filling wherever necessary (
         except rock surfaces ) shall be loosened or scarified making open furrows by
         means of a plough, or ripper or any other methods to a depth of not less than 200


                                                                                             35
TECHNICAL SPECIFICATION



         mm. deep below the stripped surface at intervals of not more than 1m. to the
         satisfaction of the Engineer-in-charge. Roots or other debris turned up during
         scarifying, shall be removed from the entire foundation area for the fill. The areas
         under the embankments shall be prevent by sprinkler before the construction of
         embankment begins. The moisture content shall be optimum.

25.8     Rock foundation:
         The treatment of the rock surface under the embankment shall be done so as to
         ensure tight bond between embankment and the foundation. This shall be done by
         the following procedure.
         i)       The area of the rock surface which is to be in contact with the embankment
                  shall be fully exposed by removing all the loose and disintegrated rock having
                  the surface of rock rugged. Hard rock projects and overhangs shall be
                  removed. If blasting is to be resorted to, care shall be taken to avoid
                  objectionable shocks to foundation rock. As far as possible the whole contact
                  area shall be exposed at one time to enable examination of rock surface
                  characteristics and planning the method of treatment.
         ii)      Exposed rock shall be benched.

26       COMPACTION:
26.1     Compaction Equipments : While the specification below provide that equipment of
         a particular type & size is to be furnished and used, it is contended that the improved
         compaction equipment as may be most suited to the prevailing site conditions and
         the programme of construction shall be used. The broad details of the equipments
         are given below:-

26.2     Tamping roller/vibratory compactors shall be used for compacting the earth fill. The
         sheep foot rollers shall meet the following requirements:-

         (i)      Roller Drums :- Each drum of a roller shall have an outside diameter of not
                  less than 150 cm and shall be not less than 120 cm not more than 180 cm in
                  length. The space between two adjacent drums, when on a level surface shall
                  not be less than 30 cm nor more than 38 cm. Each drum shall be free to pivot
                  about an axis parallel to the direction of travel. Each drum shall be equipped
                  with a suitable pressure relief valve to prevent excessive pressures from
                  developing in the interior of the roller drum.

         (ii)     Tamping Feet :- At least one tamping foot shall be provided for each 645 sq.
                  cm of drum surface. The space measured on the surface of the drum
                  between the centres of two adjacent tamping feet shall not be less than 230
                  mm. The cross sectional area of each tamping foot shall be not more than 65
                  sq. cm at a plane normal to the axis of the shank 150 mm from the drum
                  surface and shall be maintained at not less than 45 sq. cm nor more than 65
                  sq. cm at a plane normal to the axis of the shank 200 mm from the drum
                  surface.

         (iii)    Roller Weight :- The weight of the roller when fully loaded shall not be less
                  than 7091 Kg and the ground pressure when fully loaded shall not be less
                  than 40 Kg/cm 2 required to obtain the desired compaction. Tractor used for
                  pulling rollers shall be of 50 H.P. to 65 H.P. power to pull the rollers
                  satisfactorily at a speed of 4 Kms/per hour when the drums are fully loaded
                  with wet sand ballast. During operation of rolling, the spaces between the
                  tamping foot shall be kept clear of materials sticking to the drum which could
                  impair the effectiveness of the tamping rollers.


                                                                                             36
TECHNICAL SPECIFICATION




26.3     Rolling :-
         (i)      When each layer of material has been conditioned so as to have the proper
                  moisture content uniformly distributed through the material, it shall be
                  compacted by passing the tamping roller. The exact number of passes shall
                  be designated by the field laboratory after necessary test. The layers shall be
                  compacted in strips over lapping to less than 0.6 m. The rollers or loaded
                  vehicle shall travel in a direction parallel to the axis of the dam. Turns shall be
                  made carefully to ensure uniform compaction. Rollers shall always be pulled.
         (ii)     If the foundation surface is too irregular to allow the use of large roller directly
                  against any structure or rock out corp, the roller shall be used to compact the
                  soil as close to the structure or rock out-crop as possible and the portion of
                  the embankment directly against the rock or the structure shall be compacted
                  with pneumatic hand tempers in thin layers. Sheep foot roller shall not be
                  employed for compaction till the thickness of the layers compacted by other
                  mean is greater by 30 cm than the depth of the foot of the roller drum.

26.4     Tamping :- Rollers will not be permitted to operate within 1.00 metre of concrete and
         masonry structures. In location where compaction of the earth fill material by means
         of roller is impracticable or undesirable, the earth fill shall be specially compacted as
         specified herein at the following locations:-
         1.       Portions of the earth fill in dam embankment adjacent to masonry structures
                  and embankment foundations designated on the drawing as specially
                  compacted earth fill.
         2.       Earth fill in dam embankment adjacent to steep abutment and location of
                  instruments.
         3.       Earth fill at locations specially designated.

         Earth fill shall be spread in layers of not more than 10 cm in thickness when loose
         and shall be moistened to have the required moisture content as specified. When
         each layer of material has been conditioned to have the required moisture content, it
         shall be compacted to the specified density by special rollers, mechanical tampers or
         by other approved methods; and all equipment and methods used shall be subject to
         approval based on evidence of actual performance and field compaction tests. The
         moisture control and compaction shall be equivalent to that obtained in the earth fill
         actually placed in the dam embankment in accordance with the specifications..

26.5     Cohesive Materials:
         a)       When each layer of material has been prepared so as to have the proper
                  moisture content uniformly distributed throughout the material, it shall be
                  compacted by passing the roller. The layer shall be compacted in strips over
                  lapping not less than 0.30 Meter. Rolling shall commence at edges and
                  progress towards center longitudinally. The roller shall travel in a direction
                  parallel to the axis of the bank. Turns shall be made carefully to ensure
                  uniform compaction. Density tests shall be made after rolling and dry density
                  attained shall be not less than 98% of the maximum dry density (standard
                  proctor) as obtained in the laboratory for the type of material used. The
                  density achieved shall not normally be less than the designed density. The
                  dry density of soil in field shall be determined in accordance with I.S. 2720
                  (Part-XXVII)-1974 or I.S. 2720(Part. XXIX)-1975.




                                                                                                   37
TECHNICAL SPECIFICATION



         b)       Standard proctor density test shall be carried out at regular intervals to
                  account for variations in the borrow area materials as well as that in situ
                  excavated material. Not less than three tests shall be carried out to indicate
                  variations in the standard proctor density attained in laboratory.
         c)       Engineer-might review the design if necessary on examination of density test
                  results and the contractor shall have no claim arising out of such a review and
                  consequent change, If any, in the design.
         d)       i)      In case embankment covers the barrels of cross drainage or any other
                          structures, first 45cm. of the embankment shall not be compacted with
                          roller but it shall be compacted with pneumatic/hand tampers in thin
                          layers. The compaction above this layer of total 45cm shall be done by
                          using suitable light rollers to avoid damage to the structure, by
                          adjusting the thickness of layers until sufficient height is achieved to
                          permit compaction by heavy rollers. Density test shall be conducted
                          form time to time on site to as certain whether the compaction is
                          attained as specified above.
                  ii)     Separate tests shall be conducted for each zone of the embankment
                          for every 1500 cubic meters of compacted earth work, at least one
                          field density test shall be taken in each layer. Minimum two density
                          tests shall be taken in each layer per day irrespective of the quantity of
                          earth work specified above. In case the test shows that the specified
                          densities are not attained, suitable measure shall be taken by the
                          contractor either by moisture correction or by entire removal and
                          relaying of layer or by additional rolling so as to obtain the specified
                          density which shall be checked again by taking fresh tests at the same
                          locations. Necessary unskilled labour required for carrying out such
                          density tests shall be provided by the contractor.
         e)       Compaction shall be achieved by the use of smooth rollers pneumatic type
                  rollers, sheep foot rollers, mechanical compactors like vibratory rollers,
                  vibrating plates,     programmers, power rammers, slope compacting
                  equipment, pneumatic tamping equipment and such other equipment as shall
                  be specified by the Engineer based on type of material and actual field tests.
         f)       The dimensions and weight of the rollers should be such as to exert a ground
                  pressure of not less than 12 kg/cm2 of tamping when it is empty and 25kgs/.
                  Cm2 When ballasted. The number of passes required for each layer to obtain
                  the specified density shall be determined by actual field tests.

26.6     Cohesionless Materials:
         a)       Where compaction of cohesionless free-draining material such as sand and
                  gravel is required, the materials shall be deposited in horizontal layers and
                  compacted to the relative density specified. The excavating and placing
                  operations shall be such that the material, when compacted, shall be blended
                  sufficiently to secure the highest practicable degree of compaction and
                  stability. Water shall be added to the materials, if required to obtain the
                  specified density depending on the method of compaction being used.
         b)       As per clause 6.6.2.1 of I.S. 4701-1982, the thickness of embankment layer
                  shall not exceed 25cm. (Loose) before compaction and it should be spread
                  over the full width of embankment and compaction shall be done by rollers or
                  tampers to obtain specified density. The thickness of the horizontal layers
                  after compaction shall not be more than 10cm.. If compaction is performed
                  by tampers, not more than 15cm. if by 8 to 10 tonnes rollers and not more



                                                                                                 38
TECHNICAL SPECIFICATION



                  than 30cm.. If compaction is performed by vibratory or pneumatic rollers or
                  similar equipment. The relative density of the compacted materials shall not
                  be less than 70 percent as determined by laboratory tests as per I.S 2720
                  Part -XIV. if compaction is performed by internal vibrators, the thickness of
                  layers shall not be more than the penetrating depth of the vibrator.

26.7     Embankment without controlled compaction

26.7.1 No materials shall be placed in any section of the earth fill portion of the embankment
       until the embankment seat for that section has been approved by Executive
       Engineer.

26.7.2 The excavating and hauling equipments shall travel over the embankment to evenly
       distribute the material and compacting effort over the whole surface.




26.8     Embankments with controlled compaction


26.8.1 Bushes, roots, sods or other perishable or unsuitable material shall not be placed in
       the embankment.

26.8.2 Unless otherwise specified, embankment materials shall be spread in successive
         horizontal layers generally not exceeding 25cm, in thickness (loose layer) in the
         zones where these are required to be laid, extending to the full width of the
         embankment including slopes at the level of the particular layer. Each layer shall be
         commenced from the edge farthest from excavation. In no case shall embankments
         be widened by material dumped from the top. Top of each layer shall be kept slightly
         depressed in the centre.

26.8.3 Extra width of 600 mm. in thickness as measured perpendicular to the slope shall be
       provided on either side so that when compacted, lines of the finished embankment
       slopes shall have not less than specified density. Later the extra width shall be neatly
       trimmed and the trimmed material shall be permitted or re-use in embankment at
       higher elevations. No payment shall be made for providing removal of the extra
       section. Removal of extra section in the embankment shall be deemed to have been
       included in the item of compaction.

26.8.4 Thickness of layers shall be adjusted with particular type of compactors used to give
       the required density by carrying out trial compaction and requisite tests and required
       number of passes should also be determined as directed by the Engineer.

26.8.5 No fresh layer shall be laid until the previous layer is properly watered and
       compacted as per requirement. The work of spreading and compaction shall be so
       adjusted as not to interfere with each other and in such a way that neither of the
       operations is held up because of non-completion of the rolling and watering. The
       surface of the banking shall at all times of construction be maintained true to required
       cross section. If the surface of any compacted layer of earth fill is too dry or too
       smooth it shall be moistened and scarified to provide a satisfactory bonding surface



                                                                                            39
TECHNICAL SPECIFICATION



         before the succeeding layer is placed. All the rollers used on any one layer of fill
         shall be of the same type and same weight.

26.8.6 The contractor shall ensure that only approved soils are used for construction of
       embankment.

26.8.7 For proper bond of the embankment done in the previous season with the new
       embankment, the work shall be carried out as detailed below.
             i)    In case of the old bank to extended horizontally. It shall be cut to a slope not
                   steeper than 1 in 4 and the surface so prepared shall be scarified and made
                   loose at least for a depth of 15cm. Necessary watering shall be done and the
                   earth surface shall be thus prepared to receive the new embankments. The
                   soils shall be laid in layers and compacted to the required degree of
                   compaction to have a proper bond with the old one.
              ii) If the old bank is to be raised vertically, vegetation shall be cleared followed
                   by scarifying, watering and placing of the new earth layer as specified above.
              iii) The surface which are damaged due to rain shall be made good by filling with
                    proper soil duly compacted by tampers. A cross slope away from the centre
                    of canal of about 1in 80 shall be maintained throughout the rainy season to
                    ensure. proper drainage in the event of occasional rainfall. No extra or
                    separate payment shall be made for these items of work.

26.8.8 Settlement allowance:
            i) The canal embankments shall be constructed to a higher elevation than that
               shown on drawings at the rate of 2.5cm. per every one meter height of bank if
               power driven equipment is used and 25cm/lmt height if other than power
               driven equipment is used for compaction towards Shrinkage /Settlement.
            ii) No extra or separate payment shall be made for this work as this shall be
                deemed to have been included in the respective item of construction and
                consolidation of embankment.
            iii) Care shall be exercised that all large clods are broken and no clod bigger than
                 say 8cm. rock, are buried in the banks.

26.9     Homogenous Section:
The homogeneous section for canal embankments shall be provided as specified in the
drawings. The available coarser and more pervious materials shall be placed nearby outer
slopes in order to have increasing permeability from inner to outer side. The compaction
shall be carried out as per clause 6.6.2 of I.S. 4701-1982.

26.10 Zonal Embankments:
In Zonal sections the selected and approved soils shall be spread to the required widths of
respective zones. All the zones shall be tackled simultaneously and the difference in level
between zone to zone shall not be more than 150mm.

27       MOISTURE CONTROL:
       The water content of the earthfill material prior to and during compaction shall be
       distributed uniformly throughout each layer of materials between –2 to + 1 of the
       optimum moisture content for casing material and between 0 to + 2 for hearting material.
       Moisture determination of soils as well as needle moisture determination of soil shall be




                                                                                                40
TECHNICAL SPECIFICATION



       carried out as per IS : 2720 (Pt. II) 1973, sec 1 and designation E22 of USBR / Earth
       Manual 1968 respectively.
        Laboratory investigations may impose some restrictions on the lower limits of the
        practicable moisture contents on the basis of studies on consolidation characteristics of
        soils in embankment. Hereinafter the term range of optimum practicable moisture
        content shall refer to the value as described above. As far as practicable, the material
        shall be placed at proper moisture content. If additional moisture is required, it shall be
        added by sprinkling water before rolling of a layer. If the moisture is greater than
        required, the material shall be spread and allowed to dry before starting rolling.
        Moisture control shall be strictly adhered to. The moisture content shall be relatively
        uniform throughout the layer of material. If necessary, ploughing, disking, harrowing or
        blending with other materials may have to be resorted to, to obtain uniform moisture
        distribution. If the moisture content is more or less than the range of optimum
        practicable moisture content, or if it is not uniformly distributed throughout the layer,
        rolling and adding of further layer shall be stopped. Further work shall be started again
        only when the above conditions are satisfied.
        The Moisture content of the earthfill placed against any rock outcrop or any structure
        shall be slightly above the optimum, to allow it to be compacted into all irregularities of
        the rock and this shall be determined by the field tests.

28       SPECIAL PRECAUTIONS:
28.1     During the actual construction of any earth work, maximum use should be made of
         construction plant and routing of the plant should be carefully controlled to obtain
         uniform compaction over as wide an areas as possible. Care should also be taken
         during the compaction operation to shape the surface of the works to facilitate the
         shedding and to minimize the absorption of rain water, particular attention being
         given to the prevention of pending of water. The contractor shall do this at the end of
         each day’s work.

28.2     The earth moving machinery shall not be allowed to pass over a compacted portion
         of the embankment beyond certain limits by varying the hauling routes and ramps,
         thus ensuing that over compaction does not take place in any particular reach.

28.3     During the Construction, a small transverse slope from centre towards the edges
         shall be given and further in the reach when bank is being raised, the works shall be
         tackled in continuous horizontal layers to avoid pools of water and concentration of
         allow of water during rains, which will cause damages, scours and rain gullies.

28.4     Special precautions shall also be taken while rolling the spread soil near structures,
         conduit, sluice barrels, filters, rock toes at the junctions of bank connections with the
         structures, using hand or power tampers. It is essential that the compaction of filling
         should be carried out in such a manner as to avoid an unbalanced thrust on walls
         etc., which might displace or damage it. The equipment shall be provided with
         suitably shaped heads to obtain the required density.

29       DOWEL BANKS:
29.1     Dowel Banks shall be constructed to the dimensions, grades, slopes as shown on
         the drawings.




                                                                                                41
TECHNICAL SPECIFICATION



30       WEATHER CONDITIONS:
30.1     Embankment soils shall be placed only when the weather conditions are satisfactory
         to permit accurate control of the moisture content in the embankment material.
         Before closing work in embankment, in any continuous reach prior to setting of
         monsoon, the top surface shall be graded and rolled with a smooth wheeled roller to
         facilitate run-off away from canal. Prior to resuming work, the top surface shall be
         scarified and moistened or allowed to dry as necessary.

30.2     The Contractor shall provide suitable protection works protect the slope from erosion
         due to rain water. No payment whatsoever shall be made for providing such
         protection work and rectifying any monsoon damages.

31       DRESSING SLOPES
         The outside slopes of the embankment shall be neatly dressed to lines and grades
         as placement of fill progress.

All humps and hollows varying more than 15 cm from the neat lines of the embankment shall
       be regarded. Material used to fill depression shall be thoroughly compacted and
       bonded to the original surface. Slopes shall be maintained until final completion and
       acceptance. Any material that is lost by rains, weathering or other cause shall be
       replaced at his cost of agency executing the work.

32       SETTLEMENT ALLOWANCE
32.1     In the earth fill embankment watered, rolled and compacted at optimum moisture
         content and at dry density expressed as percentage of proctor’s maximum dry
         density as given in Appendix-I, settlement allowance of 1% and 2% of the designed
         height for un-yielding (rock) and compressible (soil) foundations respectively shall be
         provided. The base width of the dam will not be increased to maintain the design
         slopes indicated in the drawings for the additional height as settlement allowance, but
         the following procedure will be adopted.

32.2     Settlement allowance will be calculated at various levels, where the slope is to be
         changed and elevations including settlement allowance will be derived. The
         embankment width at the designed levels remaining same. The edges of
         embankment at the increased elevation (including settlement), when joined with the
         point where the slope has changed earlier below shall give the slope to be adopted
         for construction.

32.3     If the embankment is raised in more than one season, provision for settlement shall
         be made in the last season’s construction by slight steepening of slopes near the top.

33       TOE DRAINS :
33.1      Pitched toe drains with filter will be provided throughout the length of the dam at the
         downstream toe of earth dam as indicated in the drawings and as per the details
         shown therein. The layer of horizontal filter under the casing portion of dam shall be
         extended in the toe drains to specified thickness. The filter shall be watered and
         tamped with hand tampers.

33.2     The useful excavated material out of the toe drain shall be suitably utilised on the
         dam as directed by the Engineer-in-Charge.



                                                                                              42
TECHNICAL SPECIFICATION



34       SURFACE DRAINS:
34.1     This work shall consist of constructing surface drains, Schedule of work shall be so
         arranged that the drains are completed in proper sequence with canal excavation
         works as necessary subsequently or no damage is caused to these works due to lack
         of drainage.

34.2     Surface drains shall be excavated to the specified lines, grades, levels and
         dimensions. The excavated soils shall be removed from the area adjoining the
         drains. and is found suitable utilized in embankment construction. All unsuitable soils
         shall be disposed off as directed.

34.3     The excavated bed and sides of drains shall be dressed to bring these in close
         conformity with the specified dimensions, levels and slopes.

34.4     All works on drain constructions shall be planned and executed in proper sequence
         with other works as approved by Executive Engineer with view to ensure adequate
         drainage for the area.

35       SIDE DRAINS:
35.1     The location, grades and sections of the drains shall be as shown on the drawings
         and or as directed. Measurement of excavation for the above drains will be made to
         the lines shown on the drawings or as directed.

36       ROAD SURFACES AND PARAPETS
36.1     Road shall be constructed at the top of the embankment and at other locations as
         indicated in the drawing. The roadway shall be as indicated in drawing. The
         construction shall be as specified for the highway by I.R.C. or as directed by the
         Engineer-in-Charge.

36.2     The parapets shall also be constructed after allowing sufficient time for the
         embankment to undergo the usual post construction settlement in order to avoid
         cracking of the walls due to differential settlement.

37       PROTECTION:
37.1     The contractor shall take all precautions necessary for the protection of the work by
         diversion of stream local surface drainage, rain water etc. if these are likely, to
         damage the work. Any damage to earth work due to any reason what so ever shall
         be made good by the contractor at his cost till the work is certified as completed and
         takeover by the Superintending Engineer/Engineer-in-Charge.

38       ROADS AND RAMPS:
38.1     The contractor shall construct, operation, and maintenance roads and earth ramps
         adjacent to the canal and structures at his own expanses. Suitable materials from
         excavation or borrow areas shall be placed as embankment for the roads and ramps.
         The width of the road shall be not less than 4.25M.




                                                                                             43
TECHNICAL SPECIFICATION



39       DRY STONE PITCHING :
39.1     The depth of stones shall be about equal to the specified thickness of pitching and
         shall generally be not less than 0.014 cum or 0.021 cum as specified in the
         appropriate item of USR or other size as ordered by the Engineer-in-Charge having
         regard to the nature of stones being quarried. The small size stones/spalls required
         for pitching and wedging shall be brought to the site only to the required extent and
         they shall not to be used in two or more thickness as a substitute for the stones of full
         thickness. A large amount of the stones for pitching shall be obtained from the
         required excavation for other parts of the work. Additional rock as required shall be
         obtained from rock quarries.


39.2     Placing

Backing of filter and/or spalls where specified on drawing shall be placed only after          the
underlying slope shall be trimmed neatly to the slopes and grades established on               the
drawings. The lowest course of pitching shall be started from the toe wall or the line of      pin
headers at the toe of the slope as may be specified on the drawing and the pitching           laid
course by course up the slope.

Projecting corners shall be knocked off with the hammer so as to make a rough joint at the
base. The stones shall be laid on end with broadest base down and length normal to the
slope and carefully bonded in all directions and firmly bonded on the backing of filters where
provided. The stones shall be packed with hammer of mallet closed against each other, their
general line being approximately perpendicular to the slope of the underlying surface.

After the stones have been fixed as above, the interstices shall be filled with well fitting chips
driven home.

The general face slope of the pitching when completed shall be as specified in the drawing
subject to the tolerance as given in para 39.3 below. The final surface of the pitching shall be
clear off all refuge.


39.3 Tolerance : The tolerance on the nominal thickness of rip-rap enforced on the
   performed profile shall be 10 (Ten) percent.

40       DRY PICKED UP BOULDER PITCHING
40.1     The boulders used in this type of pitching shall consists of the rolled rock masses
         directly picked up in their natural form from the river or the nalla beds. The boulders
         shall be hard, dense and resistant to abrasion. The size of the boulders in at least
         one direction should not normally be less than 22 cm. Also the least dimension of
         such boulders in any direction should not be less than 10 cm. The smaller size
         boulders/gravels required for packing and wedging shall be brought to the site only to
         the required extent and shall not be used in two or more layers as a substitute for the
         boulders of full thickness.

40.2     Placing :
         Over the backing of filter as may be specified in the drawing, the boulders shall be
         placed such that the direction in which the size of boulder is around 22 cm is placed




                                                                                               44
TECHNICAL SPECIFICATION



         normal to the surface of under layer. Also the boulders shall be laid with broadest
         base down and carefully bonded in all directions.

         After the boulders have been fixed as above, the interstices shall be filled with well
         fitting smaller size boulders / gravel driven home.

         The general face sloe of the pitching when completed shall be as specified in the
         drawing subject to the tolerance as given in para 39.3. The final surface of the
         pitching shall be clean off all refuge.

41 DRY QUARRIED BOULDERS PITCHING
41.1     The specification as in Clause 39 shall be followed except that the boulders of
         required size shall be obtained by breaking big size boulders.

41.2     The depth of stones shall be about equal to the specified thickness of pitching and
         shall generally be not less than 0.014 cum or 0.021 cum as specified in the
         appropriate item of USR or other sizes as ordered by the Engineer-in-Charge having
         regard to the nature of stones being quarried. The small size stones/ spalls required
         for pitching and wedging shall be brought to the site only to the required extent and
         they shall not to be used in two or more thickness as a substitute for the stones of full
         thickness. A large amount of the stones for pitching shall be obtained from the
         required excavation for other parts of the work. Additional rock as required shall be
         obtained from rock quarries.

41.3     Placing : Backing of filter and/or spalls where specified on drawing shall be placed
         only after the underlying slope shall be trimmed neatly to the slopes and grades
         established on the drawings. The lowest course of pitching shall be started from the
         toe wall or the line of pinheaders at the toe of the slope as may be specified on the
         drawing and the pitching laid course by course up the slope.

41.3.1 Projecting corners shall be knocked off with the hammer so as to make as rough joint
       at the base. The stones shall be laid on end with broadest base down and length
       normal to the slope and carefully bonded in all directions and firmly bonded in all
       directions and firmly bonded on the backing of filters where provided. The stones
       shall be packed with hammer of mallet closed against each other their general line
       being approximately perpendicular to the slope of the underlying surface.

41.3.2 After the stone have been fixed as above, the interstices shall be filled with well fitting
       chips driven home.

41.3.3 The general face slope of the pitching when completed shall be as specified in the
       drawing subject to the tolerance as given in para 39.3. The final surface of the
       pitching shall be clean off all refuge.

42       ROCK TOE
42.1     The rock fill shall consist of free draining mixture of rock fragments of sizes from
         75mm to 250mm. A large amount of material may be obtained from required
         excavation for other parts of the work. Additional, as required shall be obtained from
         rock quarries.

42.2     Successive loads of material shall be dumped as to secure the best practicable
         distribution of materials. The large rock fragments shall be placed on the outer slopes
         and the smaller fragment shall be placed towards the earth fill side. In general, the


                                                                                               45
TECHNICAL SPECIFICATION



         downstream toe shall be placed in the manner to be approved by the Engineer-in-
         Charge.

42.3     The rock fill shall be placed in horizontal layers not exceeding 90 cm in thickness.
         The completed fill shall be stable and no large unfilled spaces shall be present in the
         fill.

42.4     Large voids, shall not be allowed on the downstream face of the rock toe, so as to
         prevent choking by the spilling of earth, rain cuts, etc. during and after construction.
         Such voids shall be properly packed with stone chips of suitable sizes. The surface of
         the rock toe shall be kept clear of all earth and debris so as not to choke its full
         drainage capacity.

42.5     The filter layers to be provided behind and below the rock toe shall satisfy the
         requirements of as below

42.6     BASE FILTER BLANKETS:
            a)    As and where indicated in the approved drawings, filter blanket should
                  be laid on the base, under the down stream portion of the canal
                  embankment. The number of layers in the filter blankets and the
                  thickness of each layer shall be as specified in the drawings. Sand
                  shall be placed and compacted to an average relative density of 85%
                  with a minimum relative density of 70%. The filter shall be placed and
                  tamped in to place in such a manner that mixing of filter with
                  foundation or backfill materials will not occur. The filter materials
                  should satisfy the following criteria.

42.6.1 The filter material shall consist of clean, sound and well graded aggregate. The
       material shall be free from debris, wood, vegetable matter, decomposed rock and
       other deleterious matter. The gradation of each filter layer shall meet the following
       requirements with respect to the material to be protected and also with respect to the
       adjacent filter layers.
                   i)     D. 15 of Filter material > 4 < 20
                          D. 15 base material
                          Provided the filter does not content more than 5% of material finer
                          than 0.07 mm (No. 200 Sieve).
                   ii)    D. 15 of Filter material < 5
                          D. 85 base Material
                   iii)   D. 50 of Filter material < 25
                          D. 50 base material
                   iv)    Coefficient of Curvature CC     =           (D.30)2 >/<3
                                                                      D.10 x D. 60
                   V)     Co-efficient of Uniformity : Cu =   D.60 > 6 for SW
                                                              D.10
                                and Cu     =     D.60 > 4 for GW
                                                D.10




                                                                                              46
TECHNICAL SPECIFICATION



                   Where
                   SW: Sand well Graded and
                   GW. Aggregate well graded.
          b)        The base filter materials should be well graded so as to satisfy the above
                    mentioned criteria. The grain size curve of the filter shall be roughly parallel
                    to that of base materials. In the above D-15 is the size at which 15% of total
                    soil particles are smaller. The percentage being by weight as determined by
                    mechanical analysis. The D-85 size is that at which 85% of the total soil
                    particles are smaller. It shall be laid in single layer or in layers as per the
                    drawing. If more than 1 filter layer is required the same criteria shall be
                    allow. The final filter is considered as the base material for selection of the
                    gradation of the coarse filter especially in the fine range. Filter materials
                    should not contain more than 5% of fines i.e. materials finer than 0.075 mm.
                    (passing through sieve No- 2000 I.S. sieve 75 micron) and fines should be
                    cohesion less to ensure that filter does not sustain a crack. The filter
                    should not have particles larger than 75mm. so as to minimise the
                    segregation.
          c)        D. 15 is the size at which 15% of the total soil particles are smaller, the
                    percentage being by weight, is being propped, to be determined by
                    mechanical analysis. D.85 size is that at which 85% of the total soil
                    particles are smaller. As more than one filter layer is required, similar
                    criteria is followed in each case, viz., the finer filter is considered as base
                    materials for the selection of the gradation at the coarser filter.
          d)        The requirement for grading of the filter shall be established by the tests
                    conducted in the filed laboratory on the basis of mechanical analysis of
                    adjacent materials, Mechanical analysis shall be performed of all samples,
                    which have been compacted by the methods equivalent to compaction by
                    roller, so that the individual particles are broken to their field condition in the
                    embankment.
          e)        The filter materials shall be compacted to an average relative density of
                    85% with minimum relative density of 70% as determined by the standard
                    U.S Bureau of Reclamation (Relative density test for cohesionless free
                    draining soils)
                    Dd         =        emax –e
                                         e - max -e min.
                    Where “e”     =            In place void ratio

                          e max        =            void ratio in loosened state

                          e min        =          void ratio in most compacted state, and
                          void ratio       =        Volume of Voids
                                                      Volume of solids
                  The relative density may also be computed using the maximum and min.
                  density as follows.
                   Dd = Yd max (Yd-Y min)/Yd (Yd max-Yd. min)

                   Where Yd Max = Maximum dry density of soil as obtained by the laboratory
                   procedure




                                                                                                    47
TECHNICAL SPECIFICATION



                   Yd min = Minimum dry density dry density of soil as obtained by
                              the laboratory procedure.

                   Yd = The dry density at which the soil is to be placed or the in place dry
                   density.

The thickness of each filter layer shall be less than 150mm.

43       BORROW AREAS
43.1     All materials required for the construction of impervious, semi pervious or pervious
         zones of embankment, which are not available from excavation and surplus material
         from other reaches shall be obtained from designated borrow areas as shown in
         drawings or as designated by the field laboratory.

         The limits of each borrow areas to be used in the various zones of embankment shall
         be flagged in the field and material from each borrow area shall be placed only in the
         zones for which it has been specified.

         The depth of cut in all borrow areas will be designated by the Executive Engineer and
         the cuts shall be made to such designated depths only. Shallow cuts will be permitted
         in the borrow area, if unstratified material with uniform moisture contents are
         encountered. Each designated borrow area shall be fully exploited before switching
         over to the next designated borrow pits. Haphazard exploitation of borrow area shall
         not be permitted. The type of equipment used and the operations in the excavation of
         materials in borrow areas shall be such as will produce the required uniformity of
         mixture of materials for the embankment.

         Borrow pits shall not be opened within a distance of ten times the height of the
         embankment from the toes (on either side). Borrow pits shall be operated so as not
         to impair the usefulness or mar the appearance of any part of the work or any other
         property. The surface of wasted materials shall be left in a reasonable smooth and
         even condition.

44       PREPARATION OF BORROW AREAS
44.1     All areas required for borrowing earth for embankment shall be cleared off all trees
         and stumps, roots, bushes rubbish and other objectionable material. Particular care
         shall be taken to exclude all organic matter from the material to be placed in the dam
         embankment. All cleared organic materials shall be completely burnt to ashes or
         disposed off as directed. The cleared areas shall be maintained free of vegetable
         growth during the progress of the work.

45       STRIPPING OF BORROW AREAS
45.1     Borrow area shall be stripped of topsoil, sod and any other matter which is unsuitable
         for the purpose for which the borrow area is to be excavated. Stripping operations
         shall be limited only to designated borrow areas. Materials from stripping shall be
         disposed off in exhausted borrow areas or in the approved adjacent areas, as
         directed.




                                                                                            48
TECHNICAL SPECIFICATION



46       BORROW PITS
46.1     The borrow pits shall not normally be more than 25M in length, and 10M in width and
         11/2 M. depth. A clear spacing of one meter between each pit shall be left out.

46.2     The depth of the pits shall be so regulated that their bottom does not cut the
         hydraulic gradient line having a slope 4:1 from the top edge of the embankment.

46.3     In no case the pits shall be located within 5M. from the toe of the embankment.

46.4     If the contractor excavated the pits near to the toe against to the above clauses and
         the same is observed at any time during or after the execution of work, the contractor
         has to fill the same pits with the soils suitable for hearting zone of embankment and
         compact to 98% proctor’s density at the cost of contractor.

47       BORROW AREA WATERING
47.1     Borrow area watering if needed based on laboratory tests will be done by the
         contractor as decided by the Engineer-in-Charge.

         The placement moisture content for proper compaction of earthwork should be as
         near as practicable to optimum moisture content as decided by laboratory tests.
         However, depending upon the site condition, the nature of the earth of the borrow
         area, the season of the year, the moisture content of the earth of borrow area will
         vary over a wide range. Thus it would be necessary to add water to bring the
         moisture content of borrow area earth to as near OMC as practicable. In irrigation
         projects, watering in borrow area may be done where watering at the place of fill
         does not yield required results. Wherever practicable and specially during dry months
         periodical watering of the borrow area by tankers and mobile units may be done to
         the extent possible as decided by Engineer-in-Charge.

48       ADDITIONAL SPECIFICATIONS FOR CANAL EARTHWORK :
48.1     Alignment and Layout of Canals :

48.2     No work will be started unless alignment including curves is set out, reference lines
         and check profile given in accordance with para 5 of the specification and edges of
         excavation and toes of banks etc. are dag belled or otherwise suitably demarcated as
         directed by the Engineer-in-Charge.

48.3     Canal in Cutting General :
         (i)      Excavation shall be carried out according to design with accurately graded
                  bed fall and sides properly sloped in accordance with drawings.
         (ii)     The excavation shall be done by first cutting a central trench with slopes
                  having steps with 30 cm rise and tread in accordance with the prescribed side
                  slopes. When excavation is so completed upto bed level, sides will be finally
                  trimmed to correct by knocking off the steps and dressing the slopes to as
                  smooth a surface as the nature of soil permits. In cutting in hard rock smooth
                  side cannot be obtained and it must suffice that the canal is excavated to the
                  full section and depth. Trimming of slopes shall not be started unless
                  excavation is completed to correct bed level in full width designed, and the
                  work executed is accurately checked with respect to the reference line by the
                  Engineer-in-Charge. Finishing of slopes should be done neatly and free from



                                                                                             49
TECHNICAL SPECIFICATION



                  bulges, dents and wavy and undulating surfaces. To obviate such defects,
                  trimming of slopes in small lengths less than 60 m should be avoided.
         (iii)    The classification of soils will be on the basis of classification visible at both
                  the sides of the excavation, but ridges (addies) or deadmen (Matamas) may
                  be be left at suitable intervals, if so directed by the Engineer-in-Charge for
                  facility of classification of soils.
         (iv)     Excavated materials will be utilized in accordance with typical sections of
                  canal given in the drawings, either (a) in forming the canal banks on either
                  side or (b) in embankments in other filling reaches of the canal or (c) in spoil
                  banks or (d) in any other suitable places as may be directed by the Engineer-
                  in-Charge. In case of excavation, in rock excavated stuff will be stacked as
                  directed by Engineer-in-Charge and in such way that these can be easily
                  removed or transported for other works. If so directed by the Engineer-in-
                  Charge the materials will be stacked separately according to their gradation
                  like masonry stones, rubbles, pitching stones, boulders, chips etc.

48.4     Canals in Full Cutting :
         (i)      Excavated earth will be uniformly deposited in the canal banks or in the spoil
                  banks so that the banks have a neat appearance.
         (ii)     In the case of canal service bank, which has to carry the service road for
                  inspection, earth should be deposited, in uniform layers not exceeding 20 cm.
                  Clods exceeding 10 cm in size will not be allowed without breaking them to
                  proper size.
         (iii)    In non service bank and spoil banks thickness of layer should not exceed 30
                  cm.
         (iv)     In case of all banks (including spoil banks), more gravelly material will be
                  deposited as far as possible on the top and in slopes and top of banks with
                  slope as indicated in the typical sections.
         (v)      In ridge canals continuous stretch of spoil banks shall be broken by leaving a
                  gap of 3m or more at suitable intervals of 150 metres or as directed by the
                  Engineer-in-Charge to allow for drainage or passage of traffic etc. However,
                  in case of contour canals such gaps will not be left in the upstream spoil bank
                  so that drainage water from the side long ground does not enter the canal.

48.5     Canal in Partial Cutting :
         (i)      Relevant stipulations of the sub para 48.3 above shall apply to this case also.
                  Banks will be formed in uniform layers not exceeding 20 cm thickness as may
                  be directed by the Engineer-in-Charge and no clods exceeding 10 cm will be
                  allowed. Clods exceeding 10 cm size should b broken to proper size. In case,
                  the embankment is more than 3 meter height work of watering moisture
                  control & compaction shall be done as per stipulations in para 6, 43 and 22.
         (ii)     Where the banks have to retain water, they shall be formed, if so directed,
                  with core of impervious materials, firstly from the cutting of the canal and
                  failing which from other borrow areas. Core will be covered with suitable
                  semi-pervious or pervious material that may be available.
         (iii)    Before commencing the embankment the seat will be cleared and stripped
                  and ploughed and furrowed or benched if so directed, in accordance with
                  para 7.1.1, 7.1.2.

48.6     Canal in Full Embankment not exceeding 3 m from Base to the Top :



                                                                                                 50
TECHNICAL SPECIFICATION



         All relevant stipulations of paras 48.3 to 48.5 above will apply in this case also.
         Embankments shall be made in stretches not less than 100 m.

48.7     Canal in full embankment exceeding 3 m Height from base to the Top :
         In this case construction of embankment shall follow, unless repugnant to the
         context, all the relevant specification for construction of an earth dam for a reservoir
         stipulated in paras 6, 43 and 7 subject to the modifications stipulated in para 7.1.1.
4.17.1 Striping, Benching and Furrowing and Ploughing :

48.8     The ground surface under all canal embankment excepting rock surface, where it is
         below full supply level in the canal, shall be stripped, benched or furrowed and
         ploughed as per guidelines below if not specified otherwise.

48.9     Benching : Benching should be provided only where the work is to done on highly
         undulating stiff ground, steeply sloping ground or on existing canal embankments.
         Benching shall consist of excavation of triangular trenches with a slope of 1 in 12 with
         average depth of cutting as 15 cms longitudinally below the embankment seat or in
         the form of steps with height of steps not more than 30 cms. The slope of trenches
         shall be towards the center from the outer toes of the embankment.

48.10 Stripping and Ploughing and Furrowing : Recommended treatment on embankment
      seat for stripping and ploughing and furrowing under different situation should be as
      below :-
           Type of                               Depth of stripping for
          vegetable
                              Q < 3.0 Cumecs                             Q > 3.0 cumecs
         Growth on         H > 1.5 m    H< 1.5 m        H > 0.6 m     H < 0.6 m    H > 3.0 m
           the soil
            1. Soil          8 cms        Nil only       15 cms         Nil only       15 cms
         containing a                    ploughing                     ploughing
         grass cover                        and                           and
                                         furrowing                     furrowing
               2.          Upto depth     -- do --       15 cms         -- do --     Up to dept
          Agricultural    of ploughing                                                   of
             land            but not                                                 ploughing
                           exceeding                                                  but not
                            15 cms.                                                  exceeding
                                                                                      15 cms.
Note1: Where FSL in the channel is below the ground level, neither stripping, nor ploughing
       and furrowing shall be done.
Note2:None of the treatments described in the above table shall be done for seat under spoil
      banks.
Note3: Where the depth of stripping needed is more than 15 cms, it shall be carried out only
       after approval by the Engineer-in-Charge.
         The foundation for canal embankments shall be prepared in accordance with para
         4.9.2(a) to (c) depending upon the nature of foundation materials.

48.11 Disposal of materials : In all the items of benching / stripping and preparation of
      base on rocky strata, described in para 4.17.7.1 above, the material from excavation,
      shall be deposited in specified areas in a manner as may be directed by Engineer-in-
      Charge and in such a way as not to detract from the finished appearance of the work.



                                                                                              51
TECHNICAL SPECIFICATION



48.12 Compaction :

48.13 The dry density shall not be less than 90% of M.D.D. in case of unlined canal more
      than 3 m height of embankment and lined canals irrespective of the height of
      embankment. Work of watering moisture control and compaction shall be done by
      the contractor, wherever it is so specified.

49       DRILLING AND BLASTING
49.1     Blasting where required will be permitted only when proper precautions have been
         taken for the protection of persons and property in accordance with I.S. 4081-
         1967(Indian Standard Specification for safety code for blasting and related drilling
         operations). While carrying out excavations, adequate precautions in accordance
         with I.S. 3764-1966(Indian Standard Specifications for safety code for excavation
         work) shall be taken.

49.2     Explosive such as gelatin, detonators and fuse coils etc., required for the rock
         blasting are to be procured by the Contractor at his cost. It shall be responsibility of
         the Contractor to store the explosives purchased by him in accordance with the rules
         of the explosives act and other rules framed by Government of India.

49.3     Contractor shall also furnish the following details:-




                     Capacity              License No. and date           Validity period




49.4     The contractor shall acquaint himself with all the applicable laws and regulations
         concerning storing, handling and the use of explosives. All such laws, regulations
         and rules, as prevalent from time to time shall be binding upon the contractor.

49.5     The provisions detailed in the Specifications are supplementary to the above laws;
         rules and regulations are also applicable. Further, the Engineer may issue
         modifications, alterations and new instructions from time to time. The contractor shall
         comply with the same without these being made a cause of any claims.

49.6     List I.S Codes applicable is furnished below.
             01      IS. 4081-1986 Safety Code blasting and related drilling operations.
             02      IS. 4668-1985 Ammonium nitrate for explosives.
             03      IS. 6609-19 (part 1 to5) Method test for commercial blasting explosives
                     and accessories.
             04      IS. 7632-1975 Detonators.
             05      IS. 5454-1986 Portable pneumatic Drilling machine.
             06      IS. 3764-1966 Safety code for explosives work.
                     In addition to the above I.S codes, the specifications of A.P.S.S. and
                     manual for Quality control and inspection shall also be complied with.



                                                                                              52
TECHNICAL SPECIFICATION



49.7     Excavation by blasting will be permitted only under the personal supervision of
         competent and licensed persons and trained workmen employed. by the contractor at
         his cost. All supervisors and workmen incharge of, handling, storage and blasting
         work shall be adequately insured by the Contractor.

49.8     The person incharge of the explosive magazine shall be very reliable and shall be
         approved by the Engineer.

49.9     The contractor shall make sure that his supervisor workmen are fully conversant with
         all the rules to be observed in storing, handling and use of the explosives. It shall be
         assured that the Supervisor incharge, is thoroughly acquainted with all the details of
         handling and the blasting operations.

50       USE OF EXPLOSIVES
50.1     For the transport of the explosives and detonators between the store and the site,
         closed and strong container made of soft materials such as timber, zinc, copper,
         leather shall be used.

50.2     Explosives and detonators shall be carried in separate boxes. For the conveyance of
         primer, special container shall be used.

50.3     The boxes and containers used, shall be kept closed. Explosives shall be stored and
         used chronologically, earlier received shall be used first . A make up house shall be
         provided at each working place in which cartridges will be made up by competent
         and licensed men as required for the work. The make up house shall be separated
         from other buildings. Only electric storage battery lamps shall be used in this house.

50.4     No smoking shall be allowed in the make up house or generally while dealing with
         explosives.

51       DISPOSAL OF DETERIORATED EXPLOSIVES
51.1     All deteriorated explosives shall be disposed of in approved manner the quality of the
         deteriorated explosives to be disposed of shall be intimated to the Engineer prior to
         its disposal.

52       PREPARATION OF PRIMERS
52.1     The primers shall not be prepared near open flames or fire. The work of preparation
         of primers shall always be entrusted to the same personal. Primers shall be used as
         early as possible after they are ready.

53       CHARGING OF HOLES
53.1     The work of charging of holes shall not commence before all the drilling work at the
         site is completed and the Contractor’s supervisor shall satisfy himself to that effect
         by actual inspection. While charging, open lamps shall be kept away. For charging
         with powered explosives, a naked flame shall not be allowed. Only wooden tamping
         roads, without any kind of metal on the rod shall be allowed to be used. The tamping
         roads shall have cylindrical ends. Bore hole must be of such size that the cartridges
         can easily pass down them, they shall not however be too big.




                                                                                              53
TECHNICAL SPECIFICATION



53.2     Only one cartridge shall be inserted at a time and gently pressed into the hole with
         the tamping rods. The sand, clay or other tamping materials used for filling the holes
         completely shall not be tamped too hard.

54       BLASTING
54.1     Blasting shall be carried during the fixed hours of the day which shall have the
         approval of the Engineer. The hours once fixed shall not be altered without prior
         written approval of the Engineer-in-charge.

54.2     The site of blasting operations shall be prominently demarcated by red danger flags.
         The order to fire shall be given only by the contractor’s supervisor incharge of the
         work and this order shall be given only after giving the warning signal three times, so
         as to enable all the labour, watchmen etc., to reach safe shelters.

54.3     A whistle/biggle with distinctive note shall be used to give the warning signals. The
         biggle shall not be used for any other purposes. All the labour shall be made
         acquainted with the sound of the biggle and shall be strictly warned to leave their
         work immediately at the first warning signal and to move for safe shelters. They are
         not to leave the shelters until all clear signal has been given.

54.4     All the roads and footpaths leading to the blasting areas shall be watched.

54.5     In special cases, suitable extra precautions shall be taken. The engineer-in-charge
         may however permit blasting for under ground excavation, without restriction of fixed
         time, provided that he is satisfied that proper precautions are taken to give sufficient
         warning to all concerned and that the work of other agencies on the site is not
         hampered. For lightning the fuse, a lamp with a strong flame such as a carbide lamp
         shall be used.

54.6     The contractor’s supervisor shall watch the required time for the firing of the fuses
         and shall see that all the workmen are under safe shelters in good time.

55       ELECTRICAL FIRING
55.1     Only the Contractor’s supervisor incharge shall posses key of the exploder and short
         firing accessories and he shall keep it always with himself. Special apparatus shall be
         used as a source of current for the blasting operations; power lines shall not be
         tapped for the purpose.

55.2     The detonators shall be checked before use. For blast in Series, only detonators of
         the same manufacture and of the same group of electrical resistance shall be used.
         Such of the electrical lines as could constitute danger for work of charging shall be
         removed from the site. The firing cables shall have a proper, insulating cover so as to
         avoid short circuiting due to contact with water, metallic parts of rock etc.,

55.3     The firing cables shall be connected to source of current only when nobody is in the
         area of blasting. Before firing, the circuit shall be checked by a suitable apparatus.
         After firing with or without an actual blast, the contact between the firing cable and
         the source of current shall be cut off before any one is allowed to leave the shelters.
         During storm rain the blasting operation shall be suspended.




                                                                                              54
TECHNICAL SPECIFICATION



56       PRECAUTIONS AFTER BLASTING
56.1     After the blast, the Contractor’s supervisor must carefully inspect the work and satisfy
         himself that all the charges have exploded. After the blast has taken place in the
         underground works, workmen shall not be allowed to go to the place till the toxic
         gases are evacuated from the place.

56.2     MISFIRES:- If it is suspected that part of the blast has failed to fire or is delayed
         sufficient time shall be allowed to elapse before entering the danger zone. When fuse
         and blasting caps are used, a safe time should be allowed and then the Contractor’s
         supervisor along shall leave the shelter to see misfire.

56.3     None of the drillers are to work near this hole until one of the two following operations
         have been carried out by the Supervisor.
       Either (i) the supervisor should very carefully (when the tamping is of damp
        clay)extract the tamping with a wooden scraper or jet of water or compressed air
        (using pipe of soft materials) and withdraw the fuse with the primer and detonator
        attached after which a fresh primer and detonator with fuse should be placed in this
        hole and fired out or (ii) the hole may be cleared of 300mm, of caping and the
        direction and then be ascertained by placing a stick in the hole. Another hole may be
        drilled at least 225mm away, and parallel to it. This hole should then be charged and
        fired. The balance of the cartridge and detonators found in the muck shall be
        removed.

56.4     Before leaving his work, the contractor’s supervisor should inform the supervisor of
         the relieving shift of any case of misfires and should pointout the position with red
         cross denoting the same, also stating what action if any, he has taken in the matter.
         A register of misfires and their location and how they were dealt with shall be
         maintained by the contractor.

56.5     The contractor’s supervisor should also at once report at the contractor’s office all
         cases of misfires, the cause of the same and steps were taken in connection there
         with.

56.6     The names of the day and night shift supervisors of the contractor must be noted
         daily in the contractor’s office. If misfire has been found to be due to a defective
         detonator, or dynamite, the whole quantity of box from which the defective articles
         was taken must be returned to the contractor’s office for inspection, and shall be
         disposed of.

56.7     Drilling in the holes not completely exploded by blasting shall not be permitted.

56.8     The contractor should produce the firer’s license and furnish the particulars in the
         following statement.
               Sl.                    Name                         No. of firer’s   Validity
                                                                 license & date     period
              No.




56.9     Blasting operation, when considered necessary shall be resorted to only with the
         written permission of the Engineer-in-charge. Prior inspection shall be carried out for
         the safety of the public property. Blasting operations in the proximity of over-head


                                                                                               55
TECHNICAL SPECIFICATION



         power lines, communication lines, utility lines or other structures shall not be carried
         out until the operator or the owner or both of such lines have been notified and
         precautionary measures deemed necessary have been taken.



57       BEFORE COMPACTION
57.1     Materials delivered to the fill shall be visually examined and their properties
         estimated by way of inspection. These checks shall include:
         (a)      Borrow Areas
                  (i)     Excavation of borrow areas shall be limited in extent and depth as
                          indicated on plans.
                  (ii)    Estimation of moisture content of materials by visual examination and
                          feel.
                  (iii)   Samples shall be taken for laboratory analysis in case the soil is of
                          different characteristics.
         These inspection checks shall be supplemented by sampling the materials at
         prescribed minimum intervals and by testing the samples in the laboratory for
         gradation and moisture content.
         (b)      Embankment
                  (i)     Water content tests shall be carried out in the laboratory while placing
                          the fill materials.
                  (ii)    Moisture content shall be controlled by adding water or aerating the
                          soil according to laboratory test.
                  (iii)   It shall be ensured that the methods of dumping, spreading and
                          moisture conditions are such that which results in reducing
                          segregation and/or variation of moisture content to a minimum.

58       DURING COMPACTION
         It is intended that the checks on operations during compaction shall verify :-
         (i)      That the layer thickness of the materials is as specified.
         (ii)     That the fill is compacted by the specified number of passes of the specified
                  machinery.
         (iii)    That no excessive rutting, weaving or a scaling of the fill occurs during
                  compaction.

59       AFTER COMPACTION
         The condition of the fill after compaction shall be observed and recorded particularly
         with respect of rutting or weaving. However, the properties of materials after
         compaction shall be determined primarily by field density tests. Dry density attained
         shall satisfy the compaction standards as per appendix I.

60       FREQUENCY OF TESTING
60.1     The frequencies for various tests for earthwork shall be in accordance with Appendix
         6.02 of the M.P.W.D. manual 1983, Vol. II, Part II.



                                                                                               56
TECHNICAL SPECIFICATION



60.2     Special attention shall be given to the following locations where insufficient
         compaction is likely to occur:-
                  (i)      The junction between areas of mechanical tamping and rolled
                           embankment along abutments or cut off walls.
                  (ii)     Areas where rollers turn during rolling operations.
                  (iii)    Areas where too thick a layer is being compacted.
                  (iv)     Areas where improper water content exists in a material.
                  (v)      Areas where less than specified number of roller passes were made.
                  (vi)     Areas where dirt-clogged rollers are being used to compact the
                           materials.
                  (vii)    Areas where oversized rock which has been over looked is contained
                           in the fill.
                  (viii)   Areas where materials have been placed when they contained minor
                           amounts of frost, or at nearly freezing temperatures.
                  (ix)     Areas that were compacted by rollers that have possibly lost part of
                           their ballast.
                  (x)      Areas containing materials differing substantially from the average.

61       RECORD AND REPORTS
         Record of borrow area materials and embankment placing operations be maintained
         in order to have a continuous check on the suitability and availability of fill materials
         and quality of the fill. Thus, it will be possible to have complete description of
         materials in any portion of the embankments. The records shall be maintained in the
         form specified in Appendix – II.

62       FIELD TEST DATA
62.1     Records of field test data results should be presented in the form of statistical
         analysis sheets and summary sheets in order to provide control required for
         enforcement of statistical requirements of the specifications.

62.2     The test data summary sheets and inspection reports be used to form the basis of
         construction control report, which should be issued from the site at fortnightly
         intervals during construction season. The report would contain narrative accounts of
         the progress and problems of fill construction, statistical analysis of test data and
         photographs of the fill operations.
4.15.9 EMBANKMENT TEST SECTION :
         Placing of compaction methods specified will, have to be verified by test
         embankment section to be built prior to starting of fill operations or at an early stage
         of dam construction. The initial stage of dam construction itself could be made to
         serve the purpose of test embankments. The sections referred herein shall be used
         to establish :-
         (a)    Layer thickness of fill materials.
         (b)    Optimum practicable moisture content.
         (c)    Number of passes of sheep foot roller, or weight of vibratory roller vis-à-vis
                number of passes for effective compaction.




                                                                                                  57
TECHNICAL SPECIFICATION



         When an appreciable change in material occurs, additional test sections shall be
         made during construction. The procedure for construction of test embankment
         sections is as follows :
         (i)    Select a location on the embankment where uninterrupted placing operations
                are being performed. This area 15 m by 30 m should be carefully worked and
                referenced so that its limits will be easily recognized. In order to expedite the
                determination of moisture content to be used, more than one test section may
                be established on the embankment at the same time.
         (ii)   During construction of the test section which will most probably continue for
                several shifts, a complete record of the procedure should be kept. This record
                should include the number of layers placed, the spread thickness of each
                layer, the moisture content, at which the materials were rolled, the
                designation (No. 1, No. 2, etc.) of the rollers used, the condition of the rollers
                (clean or dirty), the action of the materials being rolled (such as wavy under
                the rollers, the amount of penetration of the roller teeth after different number
                of roller trips etc.) and the borrow pit location from which the materials came.
         (iii)  Check the rollers to make certain that they meet all the requirements of the
                specifications.
         (iv)   Determine the required spread thickness of layer that will compact to the
                specified thickness after rolling specified number of times and maintain this
                thickness as long as number of roller passes is kept the same.
         (v)    Using the available data from borrow pit investigations of the materials to be
                used in the test section, the optimum moisture content as determined by
                laboratory tests will be known and 3 percent less than this moisture content
                should be used in the first 3 or 4 layers rolled.
         (vi)   After 3 or 4 layers have been placed at 3 percent less than the laboratory
                optimum moisture content, field density test should be made throughout the
                section. These tests should be made for at least each 93 sqm of test section
                area, and should be distributed over the area that they will detect the effects
                of different compaction conditions encountered during construction. For
                example, if the section is located near an abutment, certain parts of the area
                will receive more compaction from track travel than others; hence some tests
                should be made in the portion compacted only by the rollers and so reported.
         (vii)  The next step is to compact another 3 or 4 layers at the moisture content
                slightly higher (1 percent or 2 percent) than the moisture content previously
                used, maintaining the same rolled thickness of layer and number of roller
                passes as in above. Field density tests are again made over the test section.
         (viii) If the resulting field dry densities (of material passing the No. 4 sieve) from
                (vii) above shown an increase with increase of moisture, again by another 1
                percent or 2 percent, repeat the test. If an increase in moisture results in a
                decrease in field density, then place the next layers slightly dry of the original
                moisture content used and repeat the test. This procedure is nothing more
                than developing on the embankment a moisture density relation or
                compaction curve for a certain roller, thickness of layer, and a given number
                of roller trips. If special studies during investigation have indicated that the
                material being tested should be placed within certain moisture limits, or if the
                moisture limits to be used have been specified, the procedure outlined above
                should include tests at these moisture contents or at moisture contents both
                greater and smaller than the specified.
         (ix)   The roller compaction curve is now compared with the standard laboratory
                compaction curve. If the field density of materials passing the No. 4 sieve
                (from the roller curve) is greater than the standard compaction density at the
                specified moisture content, the test section should be continued decreasing


                                                                                               58
TECHNICAL SPECIFICATION



                  the number of roller trips while maintaining the specific desirable moisture
                  content until the most economical compactive effort is determined. When the
                  roller trips are decreased, the required spread thickness of layer that will
                  compact to the specified thickness of compacted material should be
                  reckoned.
         (x)      All works connected with the embankment test section will be done
                  departmentally and shall be allowed without hindrance.




                                                                                           59
TECHNICAL SPECIFICATION




                          60
TECHNICAL SPECIFICATION




                                                                            SECTION - 2
                                                             CONCRETE WORKS
                                                                                INDEX
        1 GENERAL REQUIREMENTS FOR STRUCTURAL WORKS .............................................................................. 66
        2 SCOPE ................................................................................................................................................................. 69
        3 MATERIALS ........................................................................................................................................................ 70
        4 CEMENT .............................................................................................................................................................. 70
        5 PRECAUTIONS AND GUIDELINES FOR USE OF CEMENT : ........................................................................... 70
        6 STACKING AND STORAGE : ............................................................................................................................. 70
        7 TEST ON CEMENT .............................................................................................................................................. 71
        8 MINIMUM CEMENT CONTENT REQUIRED IN CEMENT CONCRETE TO ENSURE DURABILITY UNDER
         SPECIFIED CONDITIONS OF EXPOSURE: ........................................................................................................... 71
        9 AGGREGATES .................................................................................................................................................... 72
        10 ................................................................................................................................. QUALITY OF AGGREGATES
         72
        11 .................................................................................................................................. DELETERIOUS MATERIALS
         73
        12 ...................................................................................................... MECHANICAL AND PHYSICAL PROPERTIES
         74
        13 ............................................................................................................................. SOUNDNESS OF AGGREGATE
         74
        14 ...............................................................................................................SIZE AND GRADING OF AGGREGATES
         75
        15 ........................................................................................................................................................ GUIDE LINES :
         77
        16 .................................................... MAXIMUM SIZE OF AGGREGATE FOR DAM AND APPURTENANT WORKS
         78
        17 .......................................................................................... SIZE AND GRADING OF FINE AGGREGATE (SAND)
         79
        18 ........................................................................................................................................... ALL IN AGGREGATES
         80
        19 ................................................................................................................................................ BULKING OF SAND
         80
        20 ................................................................................................................................... HANDLING AND STORAGE
         80
        21 ..................................................................................................................................... SAMPLING AND TESTING
         81
        22 ..................................................................................................................................................................... PLUMS
         81
        23 ...................................................................................................................................................... SIZE OF PLUMS
         81
        24 ............................................................................................................................................................... STORAGE
         81
        25 .................................................................................................................................................................... WATER
         81




                                                                                                                                                                                  61
TECHNICAL SPECIFICATION


        26 ..........................................................................................................................................................ADMIXTURES
         84
        27 ....................................................................................................................... INFORMATIONS ON ADMIXTURES
         84
        28 ......................................................................................................... GRADE OF CONCRETE AND TYPE OF MIX
         84
        29 ........................................................................................................................ CLASSIFICATION OF CONCRETE
         85
        30 ....................................................................................................................... CONCRETE MIX PROPORTIONING
         85
        31 .................................................................................................................. DETERMINATION OF PROPORTIONS
         86
        32 .................................................................................................................................... INFORMATION REQUIRED
         86
        33 ........................................................................................................................... DESIGN MIX PROPORTIONING :
         86
        34 ................................................................................................ LIMITATIONS OF NOMINAL MIX PROPORTIONS
         87
        35 .......................................................................................... GUIDE LINES FOR NOMINAL MIX PROPORTIONING
         88
        36 ....................................................................................................................................... QUALITY OF CONCRETE
         88
        37 .................................................................................................................................................... FIELD CONTROL
         88
        38 ................................................................................................... PRODUCTION AND CONTROL OF CONCRETE
         92
        39 .............................................................................................................................................................. BATCHING
         92
        40 .................................................................................................................................................................. MIXING :
         93
        41 .................................................................................................... EFFICIENCY AND PERFORMANCE OF MIXER
         93
        42 ....................................................................................................................................... METHOD OF CHARGING
         94
        43 ................................................................................................................................................... TIME OF MIXING :
         94
        44 ........................................................................................................................................................ DISCHARGING
         95
        45 ....................................................................................................................................................... RETEMPERING
         95
        46 ......................................................................................................................................................... HAND MIXING
         95
        47 .......................................................................................................................................................... FORM WORK
         96
        48 ...................................................................................................................................... MATERIALS TO BE USED
         96
        49 ............................................................................................................................................................... MATERIAL
         97
        50 ........................................................................................................... CLEANING AND TREATMENT OF FORMS
         98




                                                                                                                                                                                  62
TECHNICAL SPECIFICATION


        51 ............................................................................................................................................REMOVAL OF FORMS
         98
        52 ................................................................................................................. SEQUENCE OF REMOVAL OF FORMS
         99
        53 ............................................................................................................................... HANDLING AND CONVEYING
         99
        54 ................................................................................................................................................................ BUCKETS
         99
        55 .................................................................................................................................................................. CHUTES
         99
        56 ................................................................................................................................................................ PUMPING
         99
        57 ................................................................................................................................................ BELT CONVEYORS
         100
        58 ..................................................................................................... CLEANING AND WASHING OF EQUIPMENTS
         100
        59 ......................................................................................................... PREPARATION FOR PLACING CONCRETE
         101
        60 .............................................................................................................................................. ROCK FOUNDATION
         134
        61 ...................................................................................................................... EARTH OR SHALE FOUNDATIONS
         134
        62 ...................................................................................................................................... PLACING OF CONCRETE
         135
        63 .................................................................................................................................. SEQUENCE OF CONCRETE
         135
        64 ....................................................................................................................................................... WITHIN FORMS
         135
        65 ................................................................................................................................................. CLEANING JOINTS
         136
        66 ................................................................................................................................................ RATE OF PLACING
         137
        67 ....................................................................................................................... PLACING “PLUMS IN CONCRETE”
         137
        68 ..................................................................................................................................................... LARGE BLOCKS
         138
        69 ............................................................................................................................................................... FISSURES
         139
        70 ......................................................................................................................................... REJECTED CONCRETE
         139
        71 ............................................................................ CONCRETING WORK IN EXTREME WEATHER CONDITIONS
         139
        72 ............................................................................................ CONCRETE WORK UNDER WATER CONCRETING
         139
        73 ......................................................................................................................................................... COMPACTING
         141
        74 ..............................................................................................................................................................VIBRATING
         142
        75 ............................................................................................................................... INTERNAL TYPE VIBRATORS
         142




                                                                                                                                                                                63
TECHNICAL SPECIFICATION


        76 .............................................................................................................................. EXTERNAL TYPE VIBRATORS
         143
        77 .................................................................................................................................................... SURFACE VOIDS
         143
        78 ................................................................................................................................................. GREEN CUTTING :
         143
        79 .................................................................................................................................................. SAND BLASTING :
         144
        80 ........................................................................... OTHER REQUIREMENTS OF CONCRETE CONSTRUCTIONS:
         145
        81 ................... CONCRETE IN VARIOUS COMPONENTS OF BRIDGES, UNDER TUNNELS, AQUEDUCTS ETC.,
         145
        82 ................................................................................................................................EMBEDMENT IN CONCRETE:
         145
        83 ........................................................................................................................................ CURING OF CONCRETE
         146
        84 ............................................................................................... CURING OF UNFORMED SURFACES AND PIERS
         146
        85 ..................................................................................................................................................... WATER CURING
         146
        86 ............................................................................................................................................. MEMBRANE CURING
         146
        87 .................................................................................................................. FINISHING OF CONCRETE SURFACE
         147
        88 ........................................................................................... CLASSES OF FINISH FOR UNFORMED SURFACES
         148
        89 ...................................................................................................................................... REPAIRS OF CONCRETE
         149
        90 .........................................................................................................................................METHODS OF REPAIRS
         150
        91 .............................................................................................................................................. DRY PACK METHOD
         150
        92 ................................................................................................................. CONCRETE REPLACEMENT METHOD
         150
        93 ..................................................................................................................... MORTAR REPLACEMENT METHOD
         150
        94 ................................................................................................................................................. EPOXIES METHOD
         150
        95 ..................................................................................................... PREPARATION OF CONCRETE FOR REPAIR
         150
        96 .................................................................................................................................... DRY PACK OF CONCRETE
         151
        97 ................................................................................................................................. CONCRETE REPLACEMENT
         151
        98 ................................................................................................................ MORTAR REPLACEMENT – GUNITING
         152
        99 ................................................................................................................................ USE OF DRY PACK MORTAR
         152
        100 ............................................. PROCEDURE OF REPLACEMENT OF CONCRETE, CURING OF REPAIRS ETC
         152




                                                                                                                                                                         64
TECHNICAL SPECIFICATION


         101 .................................................................................................................................... COOLING OF CONCRETE
          153
         102 .............................................................................................. TOLERANCE FOR CONCRETE CONSTRUCTION
          153
      103 LOAD TEST WATER TIGHTNESS OF JOINTS OF AQUIDUCT THROUGH SYPHON AND UNDER TUNNELS
  (WATER RETAINING STRUCTURES) ............................................................................................................................. 153
         104 ...................................................................................................................... PLACING REINFORCEMENT BAR
          155
         105 .................................................................................................... SAMPLING AND STRENGTH OF CONCRETE
          155
         106 ................................................................................................................................... SAMPLING AND TESTING
          156
         107 .............................................................................................................................................. TEST PROCEDURE
          156
         108 .................................................................................................................... 7.20 STANDARD OF ACCEPTANCE
          157
         109 ....................................................................................................................................... STANDARD DEVIATION
          158
         110 .................................................................................................................. ASSUMED STANDARD DEVIATION :
          159
         111 ..................................................................................................................................... ACCEPTANCE CRITERIA
          159
         112 ..................................................................................................................................... CORE AND LOAD TESTS
          160
         113 ..................................................................................................................................... ACCEPTANCE CRITERIA
          161
         114 ......................................................................................................................................... REJECTION CRITERIA
          161
         115 ................................................................................................................................. . UNACCEPTABLE WORK :
          162
         116 ...................................................................................... CONCRETING UNDER HOT WEATHER CONDITIONS:
          162
         117 ............................................................................................... INSPECTION AND TESTING OF STRUCTURES :
          163
         118 ........................................................................................................................................................... FINISHING :
          163
         119 ........................................................................................................ CONCRETE SURFACE IRREGULARITIES :
          163
         120 ................................ FILLING FOUNDATIONS WITH EXCAVATED MATERIALS, SOIL, SAND OR MOORUM.
          164




                                                                                                                                                                                65
TECHNICAL SPECIFICATION



                            SECTION - 5: CONCRETE WORKS
The works described in the following chapter are dependent on the site conditions revealed
during investigation and implementation of the work and will be proposed by the Contractor
with due justification and will be taken up as per approval of the Chief Engineer.

1           GENERAL REQUIREMENTS FOR STRUCTURAL WORKS
1.1         Design Submissions
The contractor shall submit complete detailed design calculations of each of the components
such as canal system, foundations and superstructure of structures together with general
arrangement drawings, construction drawings and explanatory sketches as required to the
Employer’s Representative. Separate calculations for foundations or superstructures
submitted independent of each other shall be deemed to be incomplete and will not be
accepted by the Employer’s Representative.
The design considerations described hereunder establish the minimum basic design
requirements of plain and reinforced concrete structures, architechchural details, masonry
structures and structural steel works. However, any particular structure shall be designed for
the satisfactory performance fulfilling the functions for which the same is being constructed.
The Contractor shall also check the stability of partly completed structures.

1.2         Design Standards
All designs shall be based on the latest Indian Standard (I.S.) Specifications or Codes of
Practice. The design standards adopted shall follow the best / modern engineering practice
in the field based on any other international standard or specialist literature subject to such
standard reference or extract of such literature in the English language being supplied to and
approved by the Employer’s Representative. In case of any variation or contradiction
between the provisions of the I.S. Standards or Codes and the specifications given along
with the submitted tender document, the provision given in this Specification shall be
followed.
All reinforced concrete structural design shall generally confirm to the recommendations
made in the following publications of the Indian Standards Institution:

SI.NO           I.S. Number                               Description
    1 (a)       456-2000         Code of practice for plain and reinforced concrete
      1(b)      457-1963         Code of practice for plain and reinforced concrete for
      2.        875              Code of Practice for design loads for buildings and structures
      3.        1893             Criteria for earthquake resistant design of structures
      4.        2386-1977        Methods of test for aggregates for concrete
                (part 1 to 8)
      5.        516-1959         Method for test for strength of concrete
      6.        4925-1968        Specification for concrete batching and mixing plant.
      7.        1791-1985        Specification for batch type concrete mixers
      8.        650-1991         Specification for standard sand for testing cement.
      9.        2330-1986        Methods for sampling of aggregate for concrete
      10.       2722-1964        Specification for portable swing weigh batchers for concrete
                                 (single and double bucket type)



                                                                                             66
TECHNICAL SPECIFICATION



    11.         4634-1991       Batch type concrete mixers-methods test performance
    12.         5515-1983       Specification for compacting factor apparatus
    13.         5640-1970       Method of test for determining aggregates impact value of
                                soft & course aggregates
    14.         5816-1970       Method of test for splitting tensile strength of concrete
                                cylinder.
    15.         5889-1970       Specification for vibratory plate compactor
    16.         5892-1970       Specification for concrete transit mixers and agitators.
    17.         6461-1972 & Glossary of terms relating to cement concrete
                1973 Part 1 to aggregates, materials etc.,
                12
    18.         6925-1973       Method of test for determination of water soluble chlorides in
                                concrete admixtures
    19.         1838            Specification for performed fillers for expansion joints in
                                concrete pavements and structures.
    20.         7320-1974       Specifications for concrete slump test apparatus
    21.         7861-1975      Code of practice for extreme weather concreting
                &1981    (Part
                1&2)
    22.         8142-1976       Method of test for determining setting time of concrete by
                                penetration  resistance
    23.         9013-1978       Method of making curing and determining Compressive
                                strength of accelerated cured concrete test specimen.
    24.         9284-1979       Method of test for abrasion resistance of concrete
    25.         1200-1974       Method of measurement of building & engineering works,
                                concrete works.
    26.         5751-1984.      Specifications for precast concrete coping blocks
    27.         3085-1965       Method of test for permeability of cement mortar and
                                concrete.
    28.         3873-1978       Code of practice for laying in-situ cement concrete lining of
                                canals
    29.         2506-1985       General requirement for concrete vibrators screed board type
    30.         3363-1965       Specification for pan vibrators
    31.         1199-1959       Methods of sampling and analysis of concrete
    32.         3370-1965     Code of practice for concrete structures for the storage of
                &1967 (Part 1 liquids
                to 4)
    33.         2505-1980       General requirement for concrete vibrators, immersion type.
    34.         3558-1983       Code of practice for use of immersion vibrators for
                                consolidating concrete.
    35.         4656-1968       Specifications for form vibrators for concrete
    36.         8989-1978       Safety code for erection of concrete framed



                                                                                           67
TECHNICAL SPECIFICATION



                                     structures.
       37.         4990-1981         Specifications for plywood for concrete shuttering works.
       38.         6505-1985         Code of practice for installation of joints in concrete
                                     pavements.
       39.         3696-1991         Safety code of scaffolds and ladders.
       40.         IRC: 6 Part II    Standard specification and Code of Practice for road bridges
                                     Loads and Stresses
       41.         IS :289-1989      Specification for ordinary Portland cement 33 grade (forth
                                     revision) (Amendment No.6)
       42.         IS : 8041-1990    Specification for rapid hardening patterned cement (second
                                     revision) (Amendment No. 3)
       43.         IS:12600-1989     Specification for low heat pattern cement (Amendment No.5)
       44.         IS:8112-1989      Specification for 43 grade ordinary pattern cement (first
                                     revision) (Amendment No. 6)
       45.         IS:455-1989       Specification for pattern slag cement (forth revision)
All structural steel design shall generally conform to the following recommended latest
publications of the Indian Standards Institution:
(i)         IS : 800      : Code of Practice for general construction in steel
(ii)        IS : 806      : Code of Practice for use of steel tubes in general building construction

62.3         Design Requirements
The following are the design requirements for all reinforced or plain concrete structures:
       a)        M.10 grade concrete shall be used for plain cement concrete for laying screed
                 layer (i.e. bed concrete) Under the foundations of structures
       b)        M .15 and above grade of concrete shall be used for plain cement concrete for
                 casting the structural components of foundations and super structures.
       c)        M .20 and above grade of concrete shall be used for Reinforced cement
                 concrete for casting the structural components of foundations and
                 superstructures and for all concrete components of water retaining structures.
       d)        In all the above cases, the mix shall be of DESIGN MIX. For design mix, the
                 mix proportions shall be evolved in the laboratory and for the later, the
                 proportions given in the specifications shall be adopted to produce the required
                 grade of concrete. However, the minimum quantity of cement bags per cum of
                 concrete in above grades will be used as Provided in IS 456-2000 amended time
                 to time irrespective of the results of design mix.




       e)        All blinding and leveling concrete shall be a minimum 100 mm thick in concrete
                 M10 grade.
       f)        All structural reinforced concrete other than for water retaining structures shall at
                 least be of M20 grade with maximum 40 mm size downgraded coarse
                 aggregates, for footings and with maximum 20 mm size downgraded coarse
                 aggregates, for all other structural members.




                                                                                                   68
TECHNICAL SPECIFICATION



    g)       The minimum grade of concrete for water retaining structures shall be M25 with
             maximum 20 mm size downgraded coarse aggregates.
    h)       All design for structure including roof on NO CRACK BASIS.
    i)       The minimum clear cover to all reinforcement including stirrups and links shall be
             40 mm for all water retaining structures including the bottom of roof. For other
             structures the minimum clear cover shall be as specified in IS:456 -2000.
    j)       Any structure or pipeline crossing below roads shall be designed for Class A of
             IRC loading.
    k)       The bridges and supporting structure shall be designed to safely withstand the
             loadings
    l)       All pipes & conduits laid below the structural plinth & road works shall be
             embedded in reinforced concrete of grade M15 having minimum 150 mm thick
             concrete cover all around.
    m)       Approved quality water proofing compound (chloride free) shall be added during
             concreting of all liquid containing structure, in the proportion specified by
             manufacturer or 2 % by weight of cement whichever is higher.

2        SCOPE
2.1    The specifications covers the requirements of plain and reinforced concrete for
various structures and comprised of:
             1) Cost of all materials of approved quality such as specified quality of cement,
                sand, graded coarse aggregate specified, MSA, admixture (if necessary),
                water, including the cost of seigniorage charges, sampling, testing of
                materials sales tax and. any other taxes imposed by the Government,
                required to manufacture a structural component of specified grade but
                excluding the cost of steel and its fabrication charges
             2) Conveyance of all materials with all leads, and getting the mix designs
                conducted.
             3) Mixing of all ingredients by weigh batching for the mix.
             4) Hire and operations charges of all machinery (Tools, plant and equipment)
             5) Preparation of surface for placing of concrete.
             6) Cost of initial dewatering, and dewatering during execution, diversion of
                stream, and protection works as may be necessary during or after concrete
                works.
             7) Designing and construction of form work for the structural component
                including scaffolding, shuttering and removing after curing.
             8) Transporting, the concrete with all leads, lifts, delifts either by labour or by
                placing in position, vibrating, compacting, finishing and curing of the cement
                concrete, plain or reinforced and performing all other operations necessary
                and ancillary thereto, complete for finished item of works for M, 10 M, 15, M,
                20 and above concrete mixes in any structural portion or its components as
                per the drawings and as directed by the Engineer -in-charge. of the work.
             9) Sampling testing, green cutting, repairing and finishing of concrete.




                                                                                             69
TECHNICAL SPECIFICATION



3.       MATERIALS

4.       CEMENT
4.1     Unless otherwise specified cement shall conform to the following Indian Standard
Specifications.
                  (a)     Ordinary Portland cement 33 grade conforming to IS:269-1989.
                  (b)     Low heat Portland cement conforming to IS: 12600-1989.
                  (c)     Rapid hardening Portland cement conforming to IS: 8041-1978.
                  (d)     Portland slag cement conforming to IS: 455-1976
                  (e)     Portland pozzolana cement conforming to IS: 1489-1976.
                  (f)     Ordinary Portland cement 43 grade conforming to IS: 8112-1989.

5.       PRECAUTIONS AND GUIDELINES FOR USE OF CEMENT :
5.1    The type of cement to be used shall be specified by the Engineer-in-Charge.
Following guidelines are given for use of different types of cement.
         (i)      Low heat Portland cement conforming to IS: 12600-1989 shall be used with
                  adequate precautions with regard to removal of form work etc.
         (ii)     High alumina cement conforming to IS: 6452-1972 shall be used only under
                  special circumstances when directed by the Engineer-in-Charge.
         (iii)    Supersulphated cement conforming to IS: 6909-1973 shall be used only
                  under special circumstances when directed by the Engineer-in-Charge.
                  Option to use this type of cement should be taken with caution.
         (iv)     The use of Portland pozzolana cement is recommended as substitute for
                  ordinary Portland cement for plain and reinforced concrete work in general
                  building construction. In addition to 7 days compressive strength, IS: 1489-
                  1976 specifies the minimum 28 days compressive strength of Portland
                  pozzolana cement. However, for the reasons cited the rate of development of
                  early strength may be some what lower and concrete made with Portland
                  pozzolana cement may need some what longer curing period under field
                  conditions, delayed removal of form work, etc. Portland pozzolana cement
                  also has the advantage of lower heat of hydration and better sulphate
                  resistance.
         (v)      Portland pozzolana cement is not allowed for RCC work of bridges and
                  prestress concrete. Portland slag cement to be used for prestress concrete,
                  the slag content should not be more than 50%.

6        STACKING AND STORAGE :
6.1      As far as practicable, no consignment of cement shall be received and transported
         during the monsoon period.

6.2      Cement shall be stored in dry and waterproof sheds and on a platform raised about
         20 cm above ground level, and about 30cm clear off the walls. Cement bags shall be
         stacked in such a manner as to facilitate their removal and use in the order in which
         they are received. When removing bags for use, apply the “first in first out rule that is


                                                                                               70
TECHNICAL SPECIFICATION



         take the oldest cement out first. For this purpose each consignment as it comes in,
         shall be stacked separately and play card bearing the date of arrival shall be pinned
         into the pile. Each consignment of cement shall also be stacked separately therein to
         permit easy access for inspection and facilitate removal. Cement bags shall not be
         stacked more than 12 bags high to avoid lumping up under pressure.

6.3      Cement shall be stored at the work site in such a manner as to prevent deterioration
         due to moisture. The number of bags shall be kept to a minimum preferably just
         sufficient for the day’s consumption. This manner of temporary storage shall not be
         adopted in wet weather.

6.4      Handling and storage facilities shall be such that no cement is stored before use for
         more than 120 days counted from the date of dispatch by the manufacturer. Cement
         stored beyond 120 days but not exceeding 180 days shall be tested and rejected if
         found defective in any way. Cement stored beyond 120 days shall not be used for
         dams and that beyond 180 days shall not be used for structural members and
         hydraulic structures.

7.       TEST ON CEMENT
7.1      The usual tests made on cement are fineness, setting time, soundness, heat of
         hydration, compressive strength and chemical composition. All physical and chemical
         composition tests are carried out in accordance with the procedures described in IS:
         4031-1988 and IS: 4032-1985 and the results may be compared with standard as
         given in Appendix I for guidance.

7.2      The cement shall be tested also for adulteration. The frequencies of each of these
         test shall be one per every 50 tonnes.

7.3      The number of test specimen and the method of sampling shall be in accordance
         with the specification for the type of cement being tested and IS:3535-1986.

8        MINIMUM CEMENT CONTENT REQUIRED IN CEMENT
         CONCRETE TO ENSURE DURABILITY UNDER SPECIFIED
         CONDITIONS OF EXPOSURE:
         Minimum cement content required in cement concrete to ensure durability under
         specified conditions of exposure :-


         Sl.                     Exposure            PLAIN CONCRETE        REINFORCED
                                                                            CONCRETE
         No.
                                                     Minimum   Maximum   Minimum    Maximum
                                                     cement      Water   cement       water
                                                     content    cement   content     cement
                                                                 ratio                ratio
                                                      Kg/m2               Kg/m3

         Mild             For example, completely      220      0.70       250        0.65
                          protected against
                          weather, or aggressive
                          conditions, except for a
                          brief period of exposure



                                                                                             71
TECHNICAL SPECIFICATION



                          to normal weather
                          conditions during
                          construction.

         Moderate For example, exposed                250      0.60        290        0.55
                  sheltered from heavy and
                  wind driven rain and
                  against freezing, whilst
                  saturated with water;
                  buried concrete in soil
                  and concrete
                  continuously under
                  water.

         Severe           For example, exposed to     310      0.50        360        0.45
                          sea water, alternate
                          wetting and drying and to
                          freezing whilst wet,
                          subject to heavy
                          condensation or
                          corrosive fumes.




Note1 :           When the maximum water cement ratio can be strictly controlled the cement
                  content in the above table may be reduced by 10 percent.
Note2 :           The minimum cement content is based on 20mm aggregate. For 40 mm
                  aggregate, it should be reduced by about 10 percent; for 12.5 mm aggregate,
                  it should be increased by about 10 percent.

9        AGGREGATES
9.1      Natural sands and gravels are by far the most common and are used whenever they
         are of satisfactory quality and can be obtained economically in sufficient quantity.
         Crushed rock is widely used for coarse aggregate and occasionally for sand when
         suitable material from natural deposits are not economically available, although
         production of workable concrete from sharp, angular, crushed fragments usually
         requires more vibration and cement than that of concrete made with well rounded
         sand and gravel. It shall consist of (1) coarse aggregates most of which are retained
         on 4.75mm IS Sieve, but the actual size shall be in accordance with the provisions of
         the following clauses.

10       QUALITY OF AGGREGATES
10.1     Aggregates shall consist of naturally occuring (crushed or uncrushed) stone, gravels
         and sand or combination thereof. Aggregates shall be hard, strong, dense, durable,
         clean and free from veins and adherent coating, and free from injurious amounts of
         disintegrated pieces, alkali, vegetable matter and other deleterious substances. As
         far as possible, flaky, scoriaceous and elongated pieces should be avoided.




                                                                                             72
TECHNICAL SPECIFICATION



11       DELETERIOUS MATERIALS
11.1     Aggregates shall not contain any harmful materials such as pyrites, coal, lignite,
         mica, shale or similar laminated material, clay, alkali, soft fragments sea shells and
         organic impurities in such quantity as to affect the strength or durability of the
         concrete. Aggregates to be used for reinforced concrete shall not contain any
         material liable to attack the steel reinforcement. Aggregates which are chemically
         reactive with alkalies of cement are harmful as cracking of concrete may take place.

11.2     The maximum quantity of deleterious materials shall not exceed the limits specified in
         table 1 as given below, when tested in accordance with IS: 2386-1977. However, the
         Engineer-in-Charge at his discretion, may relax some of the limits as a result of some
         further tests and evidence of satisfactory performance of the aggregates.




                                                TABLE – 1
                              LIMITS OF DELETERIOUS MATERIALS

S.No.     Deleterious Substance        Method of       Fine aggregate     Coarse aggregate
                                         Test          percentage by       percentage by
                                                      weight, maximum     weight, maximum

                                                     Uncrushed Crushed Uncrushed Crushed

  1                       2                3            4         5           6           7

  (i)    Coal and lignite              IS: 2386        1.00      1.00       1.00        1.00
                                        (Pt. II)
                                         1977

 (ii)    Clay lumps                      -Do-          1.00      1.00       1.00        1.00

 (iii)   Materials finer than 75       IS: 2386        3.00     15.00       3.00        3.00
         Micron IS Sieve                 (Pt. I)
                                         1977

 (iv)    Soft fragments                 IS:2386             -     -         3.00          -
                                         (Pt. II)
                                          1977

 (v)     Shale                            -do-         1.00       -           -           -

 (vi)    Total of percentage of             -          5.00      2.00       5.00        5.00
         all deleterious materials
         (except mica) including
         sl. No. (i) to (v) for col.
         4, 6 and 7 and sl. No.


                                                                                              73
TECHNICAL SPECIFICATION



S.No.     Deleterious Substance          Method of      Fine aggregate          Coarse aggregate
                                           Test         percentage by            percentage by
                                                       weight, maximum          weight, maximum
          (i) (ii) for col. 5 only.

Note 1:           The presence of mica in the fine aggregate has been found to reduce
                  considerably the durability and compressive strength of concrete and further
                  investigations are under way to determine the extent of the deleterious effect
                  of mica. It is advisable, therefore, to investigate the mica content of fine
                  aggregate and make suitable allowances for the possible reduction in the
                  strength of concrete or mortar.
Note 2:           The aggregate shall not contain harmful organic impurities (tested in
                  accordance with IS: 2386 (Part II) 1977) in sufficient quantities to affect
                  adversely the strength or durability of concrete. A fine aggregate which fails in
                  the test for organic impurities may be used, provided that, when tested for the
                  effect of organic impurities on the strength of mortar, the relative strength at 7
                  and 28 days, reported in accordance with para 7 of IS:2386 (Part VI) – 1977
                  is not less than 95 percent.

12       MECHANICAL AND PHYSICAL PROPERTIES
12.1     Mechanical and physical properties shall be as describe in table 2 below:
                                         TABLE - 2
                            MECHANICAL AND PHYSICAL PROPERTIES
S.No.                Test result                           Specified limits of result

                                              Concrete other than for       Concrete for wearing
                                                wearing surfaces                 surfaces
  (1)                 (2)                                (3)                         (4)
   1.     Crushing value                     Shall not exceed 45%         Shall not exceed 30%

  2.      Ten percent fines value            Shall not be less than 5 Shall not be les than 10
                                             tonnes                   tonnes

  3.      Impact value by weight             Shall not exceed 45%         Shall not exceed 30%

  4.      Abrasion value           by   Los Shall not exceed 50%          Shall not exceed 30%
          Angels machine

  5.      Flakiness Index                    Not greater than 25%         As per Col. 3


13       SOUNDNESS OF AGGREGATE
13.1     For concrete liable to be exposed the actions of frost, coarse and fine aggregates
         shall pass a sodium or magnesium sulphate accelerated soundness test specified in
         IS:2386- (Part V) 1977, the limits being set by agreement between the purchaser and
         supplier, except that aggregates failing in the accelerated soundness test may be
         used if they pass a specified freezing and thawing test as described in IS: 2386(Pt.
         V) 1977, satisfactory to the user.




                                                                                                 74
TECHNICAL SPECIFICATION



13.2     As general guide it may be taken that the average loss of weight after 5 cycles shall
         not exceed the following :

(a) For fine aggregate                          10 percent when tested with sodium sulphate
                                                (Na2S04) and 15 percent when tested with
                                                magnesium sulphate (MgS04)

(b) For coarse aggregate                        12 percent when tested with sodium sulphate
                                                Na2S04) and 18 percent when tested with
                                                magnesium sulphate (MgS04)


14       SIZE AND GRADING OF AGGREGATES
14.1     Size and Grading of Coarse Aggregate – Nominal maximum size of coarse
         aggregate shall be as specified in approved drawing of work. For any one of the
         nominal sizes, the proportion of other sizes shall be in accordance with table 4.
         Graded coarse aggregate may be used in the nominal sizes of 40mm, 20mm, 16mm,
         12.5mm. Grading of graded coarse aggregate shall be also in accordance with
         table 3.




                                                                                           75
 TECHNICAL SPECIFICATION




                                                     TABLE 3 COARSE AGGREGATE


IS Sieve               Percentage passing for Single sized aggregate nominal size                Percentage passing for graded aggregate
Designat
   ion

               63 mm          40 mm       20 mm       16mm       12.5 mm      10 mm       40mm            20 mm         16mm       12.5 mm

   1               2             3           4          5           6           7           8               9            10           11

 80mm            100             -           -           -           -              -      100               -            -            -
 63mm         85 to 100         100          -           -           -              -        -               -            -            -
 40 mm         0 to 30       85 to 100     100           -           -              -    95 to 100         100            -            -
 20 mm          0 to 5        0 to 20    85 to 100     100           -              -    30 to 70        95 to 100       100          100
 16 mm             -             -           -       85 to 100     100              -        -               -        90 to 100        -
12.5 mm            -             -           -           -       85 to 100     100           -               -            -        90 to 100
 10 mm          0 to 5         0 to 5     0 to 20     0 to 30     0 to 45    85 to 100   10 to 35        25 to 55      30 to 70     40 to 85
4.75 mm            -             -         0 to 5     0 to 5      0 to 10     0 to 20     0 to 5          0 to 10      0 to 10       0 to 5
2.36 mm            -             -           -           -           -        0 to 5         -               -            -            -




                                                                                                                                           76
TECHNICAL SPECIFICATION


14.2     For any one of the nominal of coarse aggregate for mass concrete works, the
         proportions of other sizes shall be as specified in table 4.
                                         TABLE – 4
                 SIZES OF COARSE AGGREGATE FOR MASS CONCRETE
       Class and size             IS Sieve designation        Percentage passing
             1                               2                           3
Very large, 150 to 80mm                   160mm*                    90 to 100
                                           80mm                      0 to 100
Large, 80 to 40mm                          80mm                     90 to 100
                                           40mm                      0 to 10
Medium, 40 to 20mm                         40mm                     90 to 100
                                           20mm                      0 to 10
Small, 20 to 4.75mm                        20mm                     90 to 100
                                          4.75mm                     0 to 10
                                          2.36mm                      0 to 2
* There being no IS Sieve having an aperture larger than 100mm a perforated plate
complying with IS: 2405-1980 and having a square aperture of 160mm may be used.
However, if nominal maximum size of aggregate is not specified drawing, it may be
adopted with the permission of Engineer-in-Charge on basis of some guidelines
given below :

15       GUIDE LINES :
           (i)The nominal maximum size of aggregate shall be as large as possible
              within the limits specified but in no case greater than one fourth of the
              minimum thickness of the member, provided that the concrete can be
              placed without difficulty so as to surround all reinforcement thoroughly
              and filling corners of the form. For reinforced concrete work,
              aggregates having nominal size of 20mm are generally considered
              satisfactory.
        (ii) For heavily reinforced concrete members as in the case of ribs of main
              beams, the nominal maximum size of the aggregate should usually be
              restricted to 5mm less than the minimum clear distance between the
              main bars of 5mm less than the minimum cover to the reinforcement
              whichever is smaller. Where the reinforcement is widely spaced as in
              solid slabs, limitations of the size may sometimes be as great as or
              greater than the minimum cover.
        (iii) Following maximum nominal sizes of aggregate for different sizes of
              section and zone are given in table 5 and 6.
                                       TABLE – 5
   Maximum size of Aggregate Recommended for various types of concrete

  Minimum                              Maximum size of aggregate (mm)
dimension of
section (mm)
                      Non reinforced     R.C. walls         Lightly        Heavily
                           wall          beams and      reinforced or     reinforced
                                          columns      non reinforced        slabs
                                                            slabs
      (1)                  (2)               (3)              (4)            (5)
   65 to 130               20              12 to 20        20 to 40        20 to 30
  150 to 280               40              20 to 40        40 to 75          40


                                                                                       77
TECHNICAL SPECIFICATION

  305 to 740              80              40 to 75         75              40 to 75
 750 to above             160             75 to 150     75 to 150          40 to 75



16       MAXIMUM SIZE OF AGGREGATE FOR DAM AND
         APPURTENANT WORKS
                                      TABLE – 6
              Maximum size of Aggregate for Dam and Appurtenant Works

S.No.                        Location of use                           Maximum
                                                                    aggregate size in
                                                                          mm

  (1)                               (2)                                    (3)

  1.      Filling crevices in foundation of non over flow and              40
          over flow section.

  2.      Spillway and training wall sections (except exterior             75
          thickness shown in drawing).

  3.      Spillway crest, glacis, u/s face of spillway, bucket,            75
          divide wall and water face of training wall (60 cm)

  4.      All around galleries, adits, sump well, pump chamber,            40
          contraction joint and other openings.

  5.      Sandwich concrete                                                75

  6.      Deck bridge                                                      20

  7.      Top 60 cm of bucket                                              40

  8.      Bucket teeth                                                     20

  9.      Block out concrete for embaded parts of gates,                   20
          elevators, instrumentations, etc.

 10.      Foundations for divide/training wall                             75

 11.      R.C.C. wall curb, staining and piles.                            40

 12.      P.C.C. well staining                                             63

 13.      Well cap of pile, solid type piers, abutments & wing             40
          walls & their pier caps.


                                                                                      78
TECHNICAL SPECIFICATION


 14.      R.C.C. bearing                                                     20


17       SIZE AND GRADING OF FINE AGGREGATE (SAND)
17.1     The grading of fine aggregate shall be within the limits given in table 7 and
         shall be described as fine aggregate, grading zone II, II, III, IV. Where the
         grading falls out side the limits of any particular zone of sieves other than 600
         micron IS Sieve by a total amount not exceeding 5%, it shall be regarded as
         falling within that grading zone. This tolerance shall not be applied to
         percentage passing the 600 micron IS Sieve or to percentage passing any
         other sieve size on the coarse limit of grading Zone I or the finer limit of
         grading Zone IV.

17.2     Very fine sands as included in Zone IV grading should not be used except
         when the concrete is closely controlled.
                                           TABLE – 7
                                      FINE AGGREGATE

    IS Sieve                                  Percentage passing for
   Designation

                          Grading Zone-   Grading Zone-   Grading Zone–       Grading
                                I               II              III           Zone-IV

       10mm                   100             100              100                100

       4.75mm                90-100          90-100          90-100           95-100

       2.36mm                60-95           75-100          85-100           95-100

       1.18mm                30-70           55-90           75-100           90-100

     600 Micron               5-20            8-30            12-40            15-50

     150 Micron               0-10            0-10             0-10             0-15

Note 1:           For crushed stone sands, the permissible limit on 150 Micron, IS
                  Sieve is increased to 20 percent. This does not affect the 5 percent
                  allowance permitted under Clause 17.1 applying to other sieve sizes.
Note 2:           Fine aggregate complying with the requirements of any grading zone
                  in this table is suitable for concrete but the quality of concrete
                  produced will depend upon a number of factors including proportions.
Note 3:           Where concrete of high strength and good durability is required, fine
                  aggregate conforming to any one of the four grading zones may be
                  used, but the concrete mix should be properly designed. As the fine
                  aggregate grading becomes progressively finer, that is, from Grading
                  Zones I to IV, the ratio of fine aggregate should be progressively
                  reduced. The most suitable fine to coarse ratio to be used for any
                  particular mix will, however, depend upon the actual grading, particle
                  shape and surface texture of both fine and coarse aggregates.




                                                                                        79
TECHNICAL SPECIFICATION

Note 4:           It is recommended that fine aggregate conforming Grading Zone IV
                  should not be used in reinforced concrete unless tests have been
                  made to ascertain the suitability of proposed mix proportions.

18       ALL IN AGGREGATES
18.1      “All in aggregate” are generally not found suitable for making concrete of high
         quality. It shall be used only where specifically permitted by the Engineer-in-
         Charge. If combined aggregate are available they need not be separated into
         the fine and coarse, but necessary adjustments may be made in the grading
         by the addition of single-sized aggregates. The grading of the “all in
         aggregate” shall be in accordance with table 8.
                                        TABLE 8
                                All In Aggregate Grading

IS Sieve                        Percentage passing for all in aggregate of

                                   40mm Nominal size              20mm Nominal size

            80mm                           100
            40mm                        95 to 100                        100
            20mm                         45 to 75                      95 to 100
           4.75mm                        25 to 45                      30 to 50
          600 micron                      8 to 30                      10 to 35
          150 micron                      0 to 6                         0 to 6


19       BULKING OF SAND
19.1     In volume batching, sand is assumed to be dry. Dry and saturated sands
         have almost the same volume, but damp sand increases in volume. Bulking
         depends primarily upon moisture content and marginally on grading of sand.
         Due allowance for bulking of sand shall be made, while preparing the
         concrete mixes based on volume measurement.

19.2     The bulking allowance of any sample of sand shall be determined in
         accordance with procedure given in Appendix – II.

20       HANDLING AND STORAGE
20.1     Aggregates shall be stored on a clean hard surface and maintained free from
         loam and vegetable matter and exposure to dust or any other contamination.
         Aggregates of different types and sizes shall be stored in separate heaps to
         avoid mixing up. On a large job it is desirable to construct dividing walls to
         give each type of aggregate its own compartment. Fine aggregates shall be
         stacked in a place where loss due to the effect of wind is minimum. The
         aggregates shall be handled in such a manner as to minimize the breakage of
         particles. Unless specified otherwise or necessitated by site conditions
         stacking of the aggregate should be carried out in regular stacks. The
         suggested sizes for stacks are given in table 9.
                                        TABLE 9
S.No.                Material                       Size of stack (in metres)


                                                                                      80
TECHNICAL SPECIFICATION


                                           Length           Breadth          Height

(i)        Soling stone                     5.0               2.0             0.50
                                            5.0               1.0             0.50

(ii)       Coarse aggregate                 2.0               2.0             0.50
                                            5.0               5.0             1.00
                                            5.0               1.0             0.50

(iii)      Fine aggregate                   2.0               2.0             0.50
                                            5.0               5.0             1.00
                                            5.0               1.0             0.50


21       SAMPLING AND TESTING
21.1     Samples of aggregates for use on a particular major work shall be sent to the
         laboratory at least 35 days before commencement for use in the works and
         used only after obtaining the approval.

21.2     If during the course of work the source or type of any material be changed the
         samples shall be tested and used only after approval by the competent
         authority.

21.3     The method of sampling shall be in accordance with IS: 2430-1986 and tests
         shall be carried out as described in IS: 2386-1977.

22       PLUMS
22.1     All plums shall be hard, durable, clean and free from soft materials or loose
         places or deleterious substances embedded in them and shall not have sharp
         corners. The plums shall be free from adhering films or coatings and the
         crushing value of plums shall not be less than that specified for coarse
         aggregate.

23       SIZE OF PLUMS
23.1     In mass concrete members, stone plums from 150mm to 300mm size may be
         used. The maximum dimensions of these stones or plums shall not exceed
         1/3rd the least dimension of the member.

24       STORAGE
24.1      Materials shall be so stored as to prevent their deterioration or intrusion of
         foreign matter and to ensure the preservation of their quality and fitness for
         the work.

25       WATER
25.1     Water used for mixing and curing shall be clean and free from injurious
         amounts of oils, acids, alkalis, salts, sugar, organic materials or other
         substances that may be deleterious to concrete or steel. Potable water (the
         exception being water containing sugar) is generally considered satisfactory


                                                                                      81
TECHNICAL SPECIFICATION

         for mixing concrete. As a guide the following concentrations represent the
         maximum permissible values.
                          (a)   To neutralize 200 ml sample of water using
                                phenolphthalein as an indicator, it should not require
                                more than 2ml of 0.1 normal Na OH.
                          (b)   To neutralize 200ml sample of water using methyl
                                orange as an indicator, it should not require more than
                                10ml of 0.1 normal HCL.
                          (c)   Percentage of some impurities and solids shall not
                                exceed the limits given in the table 10 and 11
                                respectively.

25.2     In case of doubt regarding development of strength, the suitability of water for
         making concrete shall be ascertained by the compressive strength and initial
         setting time tests specified in 25.3 and 25.4.

25.3     The sample of water taken for testing shall represent the water proposed to
         be used for concreting, due account being paid to seasonal variation. The
         sample shall not receive any treatment before testing other than that
         envisaged in the regular supply of water proposed for use in concrete. The
         sample shall be stored in a clean container previously rinsed out with similar
         water.

25.4     Average 28 days compressive strength of at least three 15 cm concrete
         cubes prepared with water proposed to be used shall not be less than 90
         percent of the average of strength of three similar concrete cubes prepared
         with distilled water. The cubes shall be prepared, cured and tested in
         accordance with the requirements of IS : 516-1959.

25.5     The initial setting time of test block made with the appropriate cement and the
         water proposed to be used shall not be less than 30 minutes and shall not
         differ by + 30




                                                                                      82
TECHNICAL SPECIFICATION


          minutes from the initial setting time of control test blocks prepared with the
          same cement and distilled water. The test blocks shall be prepared and
          tested in accordance with the requirements of IS: 4031-1988.

25.6      The PH value of water shall generally be not less than 6.
                                        TABLE 10
 CONCENTRATION OF SOME IMPURITIES IN MIXING WATER WHICH CAN BE
                  CONSIDERED AS TOLERABLE

Sl. No.     Impurity                            Maximum Tolerable Concentration

1.          Sodium      and       potassium 1000 ppm (total) (If this is exceeded,
            carbonates and bicarbonates     tests for setting time and 28 days
                                            strength should be made)
2.          Sodium chloride                     20000 ppm
3.          Sodium sulphate                     10000 ppm
4.          Calcium      and       magnesium 400 ppm of bicarbonate ion
            bicarbonates
5.          Calcium chloride                    2 percent by weight of cement in plain
                                                concrete
6.          Iron salts                          40000 ppm
7.          Sodium    iodate,   phosphates, 500 ppm
            arsenate and berate
8.          Sodium sulphide                     Even 100 ppm warrants testing
9.          Hydrochloric and sulphuric and 10000 ppm
            other common inorganic acid.
10.         Sodium hydroxide                    0.5 percent by weight of cement if set
                                                not affected.
11.         Silt and suspended particles.       2000 ppm.
                                       TABLE – 11
                              PERMISSIBLE LIMIT FOR SOLIDS
                     Solids                          Permissible limit, Max mg/L
Organic                                       200
Inorganic                                     30000
Sulphates (as SO)                             500
Chlorides (as C0)                             2000 for plain concrete work
                                              1000 for reinforced concrete work
Suspended matter                              2000

25.7      Storage of Water
 Where water is to be stored for construction purposes this shall be done in proper
storage tanks to prevent any organic impurities getting mixed up with it.



                                                                                     83
TECHNICAL SPECIFICATION

26       ADMIXTURES
26.1     Admixtures may be used with the approval of Engineer-in-Charge for special
         purpose or for imparting special characteristics to the concrete on satisfactory
         evidence that the use of such admixtures does not adversely affect the
         properties of concrete particularly with respect to strength, volumes change,
         durability and has no deleterious effect on reinforcement and wherever so
         permitted the correct proportion and the method of use shall be as fixed by
         laboratory. The admixture shall conform to IS:9103-1979.

26.2     Materials permitted as admixtures shall have estabilished merit for any of the
         following purposes:
                  (i)      Improvement of workability.
                  (ii)     Reduction of heat evolution.
                  (iii)    Decrease in permeability.
                  (iv)     Increase in durability.
                  (v)      Accelerating of hardening, setting or strength.
                  (vi)     Increase in unit weight.
                  (vii)    Retardation of setting time.
                  (viii)   Increase in shear and bond.

26.3     Before using an admixture in concrete its performance should be evaluated
         by comparing the properties of concrete with the admixtures and concrete
         without any admixture. The chloride content of the admixtures shall be
         declared by the manufacturers. The physical requirements of an admixture
         shall be as per Appendix – III.

27       INFORMATIONS ON ADMIXTURES
27.1     To facilitate approval of an admixture the following information is needed:
         (a)      The trade name of the admixture, its source, and the manufacturer’s
                  recommended method of use;
         (b)      Typical dosage rates and possible detrimental effects of under and
                  over dosage;
         (c)      Whether compounds likely to cause corrosion of reinforcement or
                  deterioration of concrete (such as those containing chloride in any
                  form as an active ingredient) are present and if so, the chloride ions by
                  mass or expressed as equivalent anhydrous calcium chloride by mass
                  of admixtures; and
         (d)      The average expected air content of freshly mixed concrete containing
                  an admixture which causes air to be entrained when used at the
                  manufacturer’s recommended rate of dosage.

28       GRADE OF CONCRETE AND TYPE OF MIX
Concrete is composed of sand, gravel, crushed rock, or other aggregates held
together by a hardened paste of hydraulic cement and water. The thoroughly mixed
ingredients, when properly proportioned, make a plastic mass which can be cast or
moulded into a predetermined size and shape. Upon hydration of the cement by the



                                                                                        84
TECHNICAL SPECIFICATION

water, concrete becomes stone like in strength and hardness and has utility for many
purchases.

28.1      Grade of Concrete
The concrete shall be in grades designated as per Table 12.

                             TABLE 12 GRADE OF CONCRETE

             Grade designation                  Specified Characteristic compressive
                                                         strength at 28 days
                                                              (N/mm2)

                      M5                                            5
                     M 7.5                                         7.5
                     M10                                           10
                     M15                                           15
                     M20                                           20
                     M25                                           25
                     M30                                           30
                     M35                                           35
                     M40                                           40
Note 1:           In the designation of a concrete mix, letter M refers to the mix and the
                  number to the specified characteristic compressive strength of 15 cm
                  cube at 28 days, expressed in N/mM2.
Note 2:           M5 and M 7.5 grades of concrete may be used for lean concrete
                  bases and simple foundations for masonry wall. These mixes need not
                  be designed.
Note 3:           Grades of concrete lower than M15 shall not be used in reinforced
                  concrete.
Note 4:           Grades of concrete lower than M30 shall not be used in past
                  prestressed concrete & M40 for pre-tensioned prestressed concrete.

29        CLASSIFICATION OF CONCRETE
29.1      Concrete can be classified either as “Nominal mix concrete” or “Designed mix
          concrete” as specified below:
                  Designed Mix : Where the mix proportion are fixed by designing the
                  concrete mixes is called “Designed Mix”.
                  Nominal Mix : Where nominal concrete mix is adopted, such concrete
                  shall be called “Nominal concrete mixes.

30        CONCRETE MIX PROPORTIONING
30.1      The mix proportions shall be selected to ensure that the workability of the
          fresh concrete is suitable for the conditions of handling and placing, so that
          after compaction it surrounds all reinforcements and completely fills the
          formwork. When concrete is hardened, it shall have the required strength,
          durability and surface finish.




                                                                                       85
TECHNICAL SPECIFICATION

31       DETERMINATION OF PROPORTIONS
31.1     The determination of proportions of cement, aggregates and water to attain
         the required strengths shall be made as follow :
                  (a)     By designing the concrete mix.
                  (b)     By adopting nominal concrete mix.

31.2     Design mix concrete is preferred to nominal mix. The nominal mix concrete
         should be restricted to works of minor nature in which the strength of concrete
         is not critical. If design mix concrete cannot be used for any reason on the
         work for grades of M20 or lower, nominal mixes may be used with the
         permission of Engineer-in-Charge.

32       INFORMATION REQUIRED
32.1     In specifying a particular grade of concrete, the following information shall be
         included.
                  (a)     Type of mix, that is, design mix concrete or nominal mix
                          concrete;
                  (b)     Grade designation as specified in table 12.
                  (c)     Type of cement
                  (d)     Maximum nominal size of aggregate.
                  (e)     Minimum cement content (for design mix concrete);
                  (f)     Maximum water cement ratio;
                  (g)     Workability; and
                  (h)     Mix proportion (for nominal mix concrete).
                  In appropriate circumstances, the following additional information may
                  be specified.
                  (a)     Type of aggregate,
                  (b)     Maximum cement content, and
                  (c)     Whether an admixture shall or shall not be used and the type
                          of admixtures and the conditions of use.

33       DESIGN MIX PROPORTIONING :
33.1     The mix shall be designed to produce the grade of concrete having the
         required workability and a characteristic strength not less than appropriate
         values given in table 12.

33.2     As long as the quality of the materials does not change, a mix design done
         earlier may be considered adequate for later work.

33.3     Nominal Mix Proportioning
         Nominal mix by weight.
33.3.1 The proportions of materials for nominal mix shall be as given in table 13 on
       the basis of weight of cement and aggregates.
                                         TABLE 13


                                                                                      86
TECHNICAL SPECIFICATION

                             Proportions for Nominal Mix Concrete
     Grade of                Total quantity of dry     Proportion of fine      Quantity of
     concrete             aggregates by Mass per         aggregate to         water per 50
                           50 Kg. of cement, to be     coarse aggregate       Kg. of cement
                           taken as the sum of the        (By Mass)               (Max)
                          individual masses of fine
                           and coarse aggregates,
                                    (Max).
                                     Kg.                                           Litre
         1                            2                         3                    4
        M5                           800                     Generally              60
       M7.5                          625                1:2 but subject to          45
       M10                           480                an upper limit of           34
       M15                           350                1:1.5 and a lower           32
       M20                           250                   limit of 1:2.5           30


Note :            The proportions of the fine to coarse aggregates should be adjusted
                  from upper limit to lower limit progressively as the grading of the fine
                  aggregates becomes finer and the maximum size of coarse aggregate
                  becomes larger graded coarse aggregate shall be used.
Example :         For an average grading of fine aggregate (that is, Zone II of Table 6
                  the proportions shall be 1:0.5, 1:2 and 1:2.5 for maximum size of
                  aggregate 10mm, 20mm and 40mm respectively.

33.4     Nominal Mix concrete by volume
Nominal mix proportion by volume under special circumstances, may be permitted by
Engineer-in-Charge. A rough guide for the nominal mix proportions by volume will be
1:4:8, 1:3:6, 1:2:4 and 1:1.5:3 for M7.5, M10, M15 and M20 concrete respectively.
For cement which normally comes in bags and is used by weight, volume shall be
worked out taking 50 kg. of cement as 0.035 cum in volume. The quantity of water
per 50 kg (0.035 cum) of cement shall be as specified in table 13.

34       LIMITATIONS OF NOMINAL MIX PROPORTIONS
34.1     The nominal mix proportion in Clause 33.3 and 33.4 shall be valid, provided
         that:
         (i)      Nominal maximum size of aggregate is 20mm. For other sizes of
                  aggregates, adjustments in the ratio of the weight/volume of coarse
                  and fine aggregates will be necessary as indicated in the note table
                  13.
                             (ii)    The aggregate to be used shall be dry; if not,
                                     corrections for bulking of sand (is required only in case
                                     of nominal mix by volume) and surface water of
                                     aggregate shall apply.
                             (iii)   In all cases of nominal mix, fine aggregates shall
                                     conform to the grading of Zone II or zone III as
                                     described in table 7 of Clause 17.2 “Size and Grading
                                     of Fine Aggregate”.




                                                                                           87
TECHNICAL SPECIFICATION

35       GUIDE LINES FOR NOMINAL MIX PROPORTIONING
         (1)      The cement content of the mix specified in table 13 for any nominal
                  mix shall be proportionate by increased if the quantity of water in a mix
                  has to be increased to overcome the difficulties of placement and
                  compaction, so that the water cement ratio as specified is not
                  exceeded.
                  In case of vibrated concrete, the limit of quantity of water specified in
                  table 13 may be suitably reduced to avoid segregation.
         (2)      Allowance for bulking of sand is necessary only in case of volume
                  batching. However, allowance for surface water carried by aggregate
                  should be made in all cases.
                  In the absence of exact data, only in the case of nominal mixes, the
                  amount of surface water may be estimated from the values given in
                  table 14.
                                        TABLE – 14
                      SURFACE WATER CARIED BY AGGREGATE

               Aggregate                    Approximate quantity of surface water

                                            Percent by Mass               Litre/cum
Very wet sand                                      7.5                      120
Moderately wet sand
Moist sand                                        5.00                       80
*Moist gravel or crushed rock
* Coarser the aggregate, less the                  2.5                       40
water it will carry
                                              1.25 to 2.5               20 to 40
                  (3)    If nominal mix concrete made in accordance with the
                  proportions given for particular grade does not yield the specified
                  strength, such concrete shall be classified as belonging to the
                  appropriate lower grade. Nominal mix concrete proportioned for given
                  grade in accordance with table 13, it shall not, however, be placed in
                  higher grade on the ground that the test strength is higher than the
                  minimum specified.

36       QUALITY OF CONCRETE
After materials have been selected and relative proportions determined, its use
should be controlled to best advantage. Purpose of field control involves correct
procedures of proportioning, mixing, handing, placing and curing. Field control
governs quality, uniformity and ultimate economy of the structure. Much potential
value of first class materials and optimum proportioning may be lost through
ineffective control of these procedures. The poorer the quality of the ingredients, the
greater the need for rigid control to attain satisfactory durability and strength and
therefore maximum servicable life.

37       FIELD CONTROL
37.1     The quality of all concrete shall be strictly controlled throughout the job. The
         optimum proportion of all ingredients will be determined through extensive
         laboratory tests of concrete made from the type of cement and kind of
         aggregates proposed for the work.

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TECHNICAL SPECIFICATION

37.2      In case of specified nominal mix, the proportion of ingredients shall be as
          described under Clause 33.3 “Nominal Mix Proportioning”.

37.3      The preliminary tests shall be completed well before the beginning of
          concreting operations and a complete report on the concrete forming qualities
          and suitability of available aggregates as also recommendations for their use
          at the work shall be made and approved by the Engineer-in-Charge before
          actual concreting is started.

37.4      No substitutions in the materials used on the work or alterations in the
          established proportions (except correction made for bulking of sand in case of
          volume batching and moisture content on surface of aggregate) shall be
          made unless additional tests have been conducted to show that the quality
          and strengths of the resulting concrete are satisfactory.

37.5      The Engineer-in-Charge may carryout check tests and order changes in the
          mix as may be necessary from time to time to maintain the specified quality of
          the work. No radical changes, substitutions and additions in the mix, shall be
          made without such check tests and subsequent approval.

37.6      Workability : From the stage of mixing till it is transported, placed in the
          formwork and compacted, fresh concrete should satisfy a number of
          requirements as mentioned below.
          (a)       The mix should be stable, in that it should not segregate during
                    transportation and placing. The tendency of bleeding should be
                    minimized.
          (b)       The mix should be cohesive and mobile enough to be placed in the
                    form around the reinforcement and should be able to cast into the
                    required shape.
          (c)       The mix should be amenable to proper and through compaction as
                    possible in the situation of placing and with the facilities of
                    compaction.
          (d)       It should be possible to obtain a satisfactory surface finish.
                    The above requirements of stability, mobility, compactability
                    placeability and finishability of fresh concrete mentioned above are
                    collectively referred to as “Workability”. Optimum workability of
                    concrete varies from situation to situation and concrete which can be
                    termed as workable for pouring into large sections with minimum
                    reinforcement may not be equally workable for pouring in thin section
                    with heavier concentration of reinforcement. A concrete may not be
                    workable when compacted by hand but may be satisfactory when
                    mechanical vibration is used.

 Sl.No.                                     Type                                     Slump

1      (a)      Structure with exposed inclined surface requiring low slump          25 mm
                concretes to all for proper compaction

       (b)      Plain cement concrete                                                25 mm

2      RCC structures with widely spaced reinforcement eg., solid                40 - 50 mm
       columns, piers, abutments putting well steining



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TECHNICAL SPECIFICATION


3)     RCC Structures with fair degree of congestion of reinforcement          50-75mm.
       eg., pier and abutment caps box culverts well curbs, and caps,
       walls with thickness greater than 300mm.

4)     RCC and PSC structures with highly congested reinforcement             75- 125 mm
       eg. Deck slab girders, box girder, walls with thickness less than
       300mm

5)     Underwater concreting through tremie eg., bottom plug, cast-in-         100 -200
       situ piling                                                               mm

37.7     Measures of Workability : There are following three methods for measuring
         the workability.
         (a)      Slump test
         (b)      Compacting factor test
         (c)      Vee-Bee consistency test.
               (a) Slump Test : This test is most widely used, primarily because of the
                   simplicity of the apparatus required and the test procedure. Slump test
                   is essentially a measure of “consistency” or “witness” of the mix. This
                   test is suitable for concretes of medium to high workability i.e. slump
                   25 to 125mm. For very stiff mixes having zero, slump, the slump test
                   does not indicate any difference in concretes of difference
                   workabilities.
               (b) Compacting Factor Test : It is the ratio of the weight of partially
                   compacted concrete to the weight of fully compacted concrete. This
                   test is more accurate then slump test and it is suitable for concrete
                   mixes of medium and low workability that is compacting factor of 0.9
                   to 0.8. This test is conducted as per procedure laid down in IS: 1199-
                   1959.
               (c) Vee Bee Test : This test is conducted with the Vee Bee apparatus
                   and is measured in terms of time of vibrations in seconds, required to
                   transform the concrete sample from a truncated cone (remaining after
                   removal of the cone) into a right cylinder; the time is assumed directly
                   proportional to the energy used in compacting sample. This test is
                   preferred for stiff concrete mixes having low or very low workability.
                   Detailed procedure of this test is given in IS:1199-1959.

37.8     The choice of workability depends upon the type of compacting equipment
         available, the size of the section and concentration of reinforcement. For
         heavily reinforce sections or when the sections are narrow or contain
         inaccessible parts or when the spacing of reinforcement makes placing and
         compaction difficult, concrete should be highly workable for full compaction to
         be achieved with a reasonable amount of effort. The table 15 gives ranges of
         workabilities required in term of slump, compacting factor and Vee-Bee time
         for concrete depending upon placing conditions at site. The nominal
         maximum size of aggregates makes a difference in degree of workability that
         may be suitable under a particular placing condition. The values in the table
         are only a guide notwithstanding the situation at hand and should be properly
         assessed to arrive at the desired workability in each case. Insufficient
         workability resulting in incomplete compaction may severely affect the
         strength, durability and surface finish of concrete and be uneconomical in the



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TECHNICAL SPECIFICATION

         long run. The effectiveness of vibration equipment available should also be
         assessed.

37.9     However, for guidance suggested ranges of values of workability of concrete
         to some placing conditions, measured in accordance with IS: 1199-1959 are
         given below:
                                         TABLE : 15
   Placing conditions           Degree of Workability          Value of workability
            (1)                          (2)                            (3)
Concreting of shallow                 Very low              20-10 seconds, vee-bee
sections with vibration                                     time.
                                                                        Or
                                                            0.75-0.80,      compacting
                                                            factor
Concreting   of    lightly                Low               10-15 seconds vee-be
reinforced sections with                                    time.
vibration                                                               Or
                                                            0.80-0.85       compacting
                                                            factor
Concreting     of    lightly            Medium              5-2 seconds, vee-bee time
reinforced sections without                                             or
vibration,   or     heavily                                 0.85-0.92,      compacting
reinforced section with                                     factor
vibration                                                               or
                                                            25-75mm,      slump     for
                                                            20mm aggregate.
Concreting    of    heavily               High              Above 0.92, compacting
reinforced sections without                                 factor
vibration                                                               Or
                                                            75-125mm,       slump   for
                                                            20mm aggregate
         Note : For smaller aggregate the values of slump will be lower.

37.10 Durability
The durability of concrete depends on its resistance to deterioration and the
environment in which it is placed. The resistance of concrete to weathering, chemical
attack, abrasion, frost and fire depends largely upon its quality & constituent
materials. Susceptibility to corrosion of the steel is governed by the cover provided
and the permeability of concrete. The cube-crushing strength alone is not a reliable
guide to the quality and durability of concrete; it must also have an adequate cement
content and a low water cement ratio.
One of the main characteristics influencing the durability of any concrete is its
permeability. With strong, dense aggregates, a suitably low permeability is achieved
by having a sufficiently low water-cement ratio, by ensuring as thorough compaction
of the concrete as possible and by ensuring sufficient hydration of cement through
proper curing methods. Therefore, for given aggregates, the cement content should
be sufficient to provide adequate workability with a low water cement ratio so that
concrete can be completely compacted with the means available.
Appendix IV provides guidance regarding minimum cement content and permissible
limits of chloride and sulphate in concrete.




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TECHNICAL SPECIFICATION

38       PRODUCTION AND CONTROL OF CONCRETE
38.1     Salt, clay powdery coating soluble chemical salts and light weight materials
         are usually removable by washing. Aggregates should be washed before
         batching with clear water free from alkali, salt and other impurities.

39       BATCHING
39.1     Measurement of Materials : The method of measuring materials for concrete
         shall be such that the proportions are controlled and readily checked at any
         time during the progress of the work. Materials shall be measured as per
         procedure given below:-

39.2     Weigh Batchers : All weighing devices shall be subject to approval and weigh
         batchers shall meet the following requirements:-
         (a) The accuracy shall be of the order-set for the purpose and shall be such
             that the indicated weight of any hopper full of material does not vary more
             than one percent from the required weight.
         (b) The weighing equipment shall be designed to permit ready and proper
             adjustment of the proportions of the mix.
         (c) The equipment shall be capable of so controlling the rate of delivery of
             each kind and size of materials that the combined inaccuracy in feeding
             and measuring during normal operations does not exceed 3 percent for all
             aggregates, and 1 percent for water.
         (d) The operating mechanism for measuring the amount of water shall be
             such that no leakage occurs with the valves closed. The filling and
             discharge valves shall not be opened before the filling valve is closed.
         (e) Test scale weight shall be provided and periodic checks made of the
             accuracy of all weighing equipment.

39.3     To avoid confusion and error in batching, consideration should be given to
         using the smallest practical number of different concrete mixes on any site or
         in any one plant.

39.4     A competent person shall supervise all stages of production of concrete.
         Preparation of test specimens and site test shall be properly supervised.

39.5     In proportioning concrete, the quantity of both cement and aggregate should
         be determined by mass. Where the mass of cement is determined on the
         basis of mass of cement per bag, a reasonable number of bags should be
         weighed periodically to check the net mass. Where the cement is weighed on
         the site and not in bags it should be weighed separately from the aggregates.
         Water should be either measured by volume in calibrated tanks or weighed.
         Any solid admixture that may be added, may be measured by mass; liquid
         and paste admixtures by volume or mass. Batching plant where used should
         conform to IS:4925-1968.

39.6     Except where it can be shown to the satisfaction of the Engineer-in-Charge
         that supply of properly graded aggregate of uniform quality can be maintained
         over the period of work, the grading of aggregate should be controlled by
         obtaining the coarse aggregate in different sizes and blending them in the
         right proportions when required, the different sizes being stacked in separate
         stock piles. The material should be stock – piled for several hours preferably


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TECHNICAL SPECIFICATION

         a day before use. The grading of coarse and fine aggregate should be
         checked as frequently as possible, the frequency for a given job being
         determined by the Engineer-in-Charge to ensure that the specified grading is
         maintained.

39.7     In case uniformity in the materials used for concrete making has been
         established over a period of time, the proportioning may be done by volume
         batching, provided periodic checks are made on mass/volume relationships of
         the materials. Where weigh batching is not practicable, the quantities of fine
         and coarse aggregate (but not cement) may be determined by volume with
         the permission of Engineer-in-Charge. If fine aggregate is moist and volume
         batching is adopted, allowance shall be made for bulking in accordance with
         Clause 19 “Bulking of Sand”.

39.8     A detailed note “How to batch concrete by volume” has been appended vide
         Appendix VI”.

39.9     It is important to maintain the water cement ratio constant at its correct value.
         To this end, determination of moisture contents in both fine and coarse
         aggregate shall be made as frequently as possible, the frequency for a given
         job being determined by the Engineer-in-Charge according to weather
         conditions. The amount of the added water shall be adjusted to compensate
         for any observed variations in the moisture contents. For the determination of
         moisture content in the aggregate, IS:2386 (Part III) 1977 may be referred to
         allow for the variation in mass of aggregate due to variation in their moisture
         content, suitable adjustments in the masses of aggregates shall also be
         made.

39.10 Aggregate shall        not be batched when free water is dripping from the
      aggregate.

40       MIXING :
40.1     The mixing of concrete shall be done in a batch mixer of such approved type
         as will ensure the homogeneous distribution of all ingredients. The plant shall
         be so designed and operated that all materials entering the mixer including
         water can be accurately proportioned and readily controlled. The mixing shall
         be continued until there is a uniform distribution of the materials and the
         mass is uniform in colour and consistency. If there is segregation after
         unloading from the mixer, the concrete should be remixed.

40.2     The entire batch within the mixer shall be discharged before recharging. The
         volume of mixed material per batch shall not exceed the manufacturer’s rated
         capacity.
40.3     Batching plant when total quantity is more than 20 cum.

41       EFFICIENCY AND PERFORMANCE OF MIXER
41.1     The efficiency and performance of the mixer shall be periodically checked.
         The mixing efficiency, that is an index of the uniformity of the mixed concrete,
         can be evaluated by finding the percentage variation in quantity of cement,
         fine aggregate and coarse aggregate in freshly mixed batch of concrete. The
         percentage variation between the quantities of cement, fine aggregate and
         coarse aggregate (as found by weighing in water) in the two halves of the
         batch and the average of the two halves of the batch shall not exceed the
         following limits.

                                                                                       93
TECHNICAL SPECIFICATION

             Cement                                           8 percent
             Fine aggregate                                   6 percent
             Coarse aggregate                                 5 percent
             The mixer shall comply with IS: 1791-1985 and its performance should be
             tested according to IS:4634-1968.

41.2     A mixer will be considered unsatisfactory if from three tests of any one batch
         a range in slump exceeding 25mm or a range in air content exceeding one
         percent is given between representative sample taken at different portions of
         the mixer discharge.

41.3     For any one mix, the variation in the air free unit weights of three samples
         taken from the front, centre and back of a batch of concrete in the mixer, shall
         not exceed the following:-
         For one batch                        37.2 Kg. per cum
         Average of 3 batches                 23.9 Kg. per cum
         Average of 20 batches                19.4 Kg. per cum
         Average of 90 batches                14.6 Kg. per cum

42       METHOD OF CHARGING
42.1     The proper sequence of operations for the admission of aggregates into any
         type of mixer shall be ascertained by trial runs conducted in order to
         determine the method giving the best results. The following sequence of
         charging the mixer may be adopted:
             (a) Five to ten percent of the total quantity of water required for mixing,
                 adequate to wet the drum thoroughly, shall be introduced before the
                 other ingredients in order to prevent any caking of cement on the
                 blades or sides of the mixers.
             (b) All dry ingredients (cement and both fine and coarse aggregates) shall
                 be simultaneously rebboned into the mixer in such a manner that the
                 period of flow for each ingredient is about the same. Eighty to Ninety
                 percent of the total quantity of water required for mixing shall be
                 added uniformly along with the dry ingredients.
             (c) The remaining quantity of water shall be added after all the other
                 ingredients are in the mixer.
             (d) Cobbles or a portion of the coarsest aggregate, however, may be
                 added last; this facilitates the clearance of the chutes and removes
                 any fine aggregate or cement adhering to the sides.

43       TIME OF MIXING :
43.1     Unless otherwise permitted, machine mixing of each batch shall continue for
         not less than the period indicated in Table 16. During this period the drum
         shall be rotated at a speed recommended by the manufacturer. The mixing
         period shall be timed after all materials, including water, are in the drum.
                              TABLE – 16 TIME OF MIXING




                                                                                      94
TECHNICAL SPECIFICATION


         Capacity of Mixer                              Time of Mixing

                                        Natural aggregate             Manufactured
                                                                       aggregate
One cubic metre or less               1 ¼ minutes                1 ½ Minutes
Two cubic meters                      1 ½ minutes                2 minutes
Three cubic metres or larger          2 minutes                  2½

43.2     Each mixer shall have a mechanically operated timing device for signalling
         the completion of the required mixing period. The actual time of mixing shall
         be checked at least twice during each shift and the timing device shall be
         adjusted if in error.

43.3     The timing device shall be so interlocked with the discharge gate of the batch
         hopper that timing does not start until the discharge gate is fully closed and all
         ingredients are in the drum. A suitable record shall be kept of the average
         time consumed in charging, mixing and discharging a batch during each run.

43.4     Excessive mixing, necessitating the addition of water to provide workability
         shall be avoided.

44       DISCHARGING
44.1     The full contents of the drum shall be discharged quickly so as to avoid
         segregation.

44.2     When the mixer is stopped and has been out of use for more than 30 minutes
         before placing again any ingredients in the mixer all hardened concrete or
         mortar shall be removed from the inner surface of the mixer.

44.3     The first concrete batch at the start of the day’s work shall be made richer by
         10%, the first batch of concrete from the mixer shall contain only two thirds of
         the normal quantity of coarse aggregates.

45       RETEMPERING
45.1     The retempering of partially hardened concrete or mortar requiring renewed
         mixing, with or without the addition of cement, aggregate or water, shall not
         be permitted.

46       HAND MIXING
46.1     Hand mixing shall be avoided in mass concrete construction. When hand
         mixing is permitted by the Engineer-in-Charge for small jobs or for certain
         other reasons, it shall be done on a smooth water tight platform large enough
         to allow efficient turning over of the ingredients of concrete before and after
         adding water. Mixing platform shall be so arranged that no foreign material
         shall get mixed with concrete nor does the mixing water flow out. Cement in
         required number of bags shall be placed in a uniform layer on top of the
         measured quantity of fine aggregate, which shall also be spread in a layer of
         uniform thickness on the mixing platform. Dry sand and cement shall then be
         mixed thoroughly by turning over to get a mixture of uniform colour. Enough
         water shall then be added gradually through a rose and the mass turned over
         till a mortar of required consistency is obtained. Measured quantity of coarse
         aggregate shall then be placed on the mixing platform and wetted till the


                                                                                        95
TECHNICAL SPECIFICATION

         mortar and mixture obtained is of uniform colour and required consistency. In
         hand mixing quantity of cement shall be increased by 10 percent more than
         the quantity provided in the mix design or nominal mix proportioning.

47       FORM WORK
47.1     General

47.2     Forms shall be used wherever necessary to confine the concrete and shape it
         to the required lines or to ensure against contamination of the concrete by
         material caving or sloughing from adjacent surface left by excavations or
         other features of the work. All exposed concrete surfaces having slopes of 2
         horizontal to 1 vertical or greater shall be formed.

47.3     Form work may be of timber, steel or precast concrete panels or of such other
         suitable materials or combination of such materials. Form work shall be
         substantially and rigidly constructed to the shapes, lines and dimensions
         required, efficiently propped and braced to prevent deformation due to
         placing, vibrating and compacting concrete, other incidental loads or to the
         effect of weather. If settlement or deflection of forms under the load of fresh
         concrete is to be expected allowance should be made in the original
         construction of the forms so that the finished lines and dimensions of the
         structure are in accordance with those specified on the drawings.

47.4     The surfaces of form work shall be made to produce surface finishes as
         specified and form work joints space be tight enough to prevent loss of liquid
         from concrete. Joints between the form work and existing concrete structures
         shall also be grout tight. Form work shall be arranged to facilitate easing and
         removing of the various parts in correct sequence, without jarring or
         damaging the concrete. Fixing blocks, bolts, or similar devices may be
         embedded in the concrete, provided they do not reduce the strength or
         effective cover of any part of the structure below the required standard but the
         use of through bolts shall be avoided wherever possible. Temporary opening
         shall be provided at all points necessary in the forms to facilitate clearing and
         inspection immediately before the placing of the concrete.

47.5     Forms shall overlap the hardened concrete in the lift previously placed by not
         more than 75mm, and shall be tightened smugly against the hardened so that
         when concrete placement is resumed, the forms will not spread and allow
         offsets or loss of mortar at construction joints. Additional bolts or form ties
         shall be used as necessary to hold forms tight against hardened concrete.
         Particular attention shall be paid in setting and tightening the forms for
         construction joints so as to get a smooth joint free from sharp deviations or
         projections.

47.6     Moulding strips shall be placed in the corners of forms so as to produce
         chamfered edges as required on permanently exposed concrete surface.

48       MATERIALS TO BE USED
         Materials used for form sheathing and lining shall conform with the following
         requirements.

         Required         Timber sheathing or lining    Steel sheathing or lining
         finish



                                                                                       96
TECHNICAL SPECIFICATION


         F1               Any type and grade meeting        Steel sheathing permitted, Steel
                          the dimensional requirements      lining permitted except on
                          of surface finish except that     surfaces of internal transverse
                          metal forms shall be used on      and longitudinal joints in the
                          surfaces of internal transverse   dam where steel sheathing is
                          and longitudinal joints in the    required.
                          dam.

         F2               Common grade timber or Steel sheathing permitted. Steel
                          plywood sheathing or lining. lining permitted, if strongly
                                                       supported.

         F3               For plane surfaces, common Steel sheathing permitted. Steel
                          grade timber or better T & S or lining permitted, if strongly
                          plywood.                        supported.

         F4               For warped surfaces timber Steel sheathing permitted. Steel
                          which is free from knots and lining not permitted.
                          other imperfections and which
                          can be cut and bent accurately
                          to the required curvatures
                          without splintering or splitting.

         *        Steel sheathing denotes steel sheats not supported by a backing of
                  timber boards. Steel lining denotes steel sheats supported by a
                  backing of timber boards.

49       MATERIAL
         Timber sheathing or lining shall be of such kind and quality or shall be so
         treated or coated that there will be no chemical deterioration or discoloration
         of the formed concrete surfaces. The type and condition of form sheathing
         and lining and the ability of forms to withstand distortion caused by
         placement, and vibration of the concrete, and the workmanship used in the
         form construction shall be such that the formed surfaces will conform with
         applicable requirements of this specification pertaining to finish of formed
         surfaces.
         Forms for concrete surfaces required to receive F2 and F3 finishes described
         under paras 87.7, 87.8 shall be constructed so as to produce uniform and
         consistent texture and pattern on the concrete faces. Metal patches on forms
         for these faces will not be permitted. The form sheathing or lining shall be so
         placed that all horizontal form marks are continuous across the entire surface.
         Where finish F2 is specified, the sheathing or lining shall be placed so that the
         joint marks on the concrete surfaces will be in general alignment both
         horizontally and vertically and the form sheathing material used for such
         surfaces shall be restricted tone type in any one major feature of the work.
         Forms for surfaces required to receive F4 finish as described under para 87.9
         shall be constructed so as to conform accurately to the required curvature of
         the sections. Where necessary to meet requirements for curvature the from
         sheathing shall be built up of laminated splices cut to make right, smooth form
         surface. The forms shall be so constructed that the joint marks on the
         concrete surface shall in general, follow the line of water flow. After the forms
         have been constructed, all surface imperfection shall be corrected, all the
         nails shall be hidden, and any roughness and all angles on the surface of the
         forms caused by matching the forms material shall be dressed to curvature.

                                                                                         97
TECHNICAL SPECIFICATION

         If temperate hard wood is used as a form lining, it shall be continuously
         supported with timber or plywood.
         Embedded ties for holding forms shall remain embedded and except where
         F1 finish is permitted, shall terminate not less than two diameters or twice the
         minimum dimension of the tie or ten millimeters, whichever is greater, in the
         formed faces of the concrete. Where F1 finish is permitted, ties may be cut
         off flush with formed surface.
         The ties shall be constructed so that removal of the ends or and fasteners can
         be accomplished without causing appreciable spelling at the faces of the
         concrete. Recesses resulting from removal of the ends of the form ties shall
         be filled in accordance with the provisions of para 89 on repairs of concrete.

50       CLEANING AND TREATMENT OF FORMS
         At the time concrete is placed in the forms, the surface of the forms shall be
         free from encrustations of mortar, grout or other foreign material. Before
         concrete is placed, the surfaces of the forms designated to produce F2, F3
         and F4 finishes shall be oiled with a commercial form oil that will effectively
         prevent sticking and will not stain the concrete surfaces. For timber forms,
         form oil should consist of pure refined pale paraffin mineral oil or other
         approved form oil. For steel forms, form oil shall consist of refined mineral oil
         suitably compounded with one or more ingredient which are appropriate for
         the purpose.
         Care shall be taken to keep form oil out of contract with reinforcement.

51       REMOVAL OF FORMS
51.1     Except as otherwise provided in this sub-clause forms shall be removed as
         soon as the concrete has hardened sufficiently to prevent damage by careful
         form removal, thus facilitating satisfactory progress with specified curing and
         earliest practicable repair of surface imperfections.

51.2     Forms on upper sloping faces of concrete, such as forms on the water sides
         of warped transitions, shall be removed as soon as the concrete has attained
         sufficient stiffness to prevent sagging. Any needed repairs or treatment
         required on such sloping surfaces shall be performed at once and be followed
         immediately by the specified curing.

51.3     In order to avoid excessive stresses in the concrete that might result from
         swelling of the forms, timber forms for wall opening shall be loosened as soon
         as this can be accomplished without damage to the concrete.

51.4     Subject to approval, forms on concrete surface close to excavated rock
         surface may be left in place provided that the distance between the concrete
         surface and the rock is less than 400 mm and that the forms are not exposed
         to view after completion of the works.

51.5     Forms shall be removed with care so as to avoid injury to the concrete. Any
         concrete damage in form removal shall be repaired in accordance with the
         provisions of para 89 repair of concrete.

51.6     The following minimum intervals of time as per IS:456-1978 will generally be
         allowed when using ordinary Portland cement between placing concrete and
         striking form work but the period shall be modified in case of wet weather and
         also at the option of the Engineer-in-Charge.

                                                                                       98
TECHNICAL SPECIFICATION


         (a)    Walls columns and vertical faces of all 24 to 40 hours
                structure members
         (b)    Slabs (props left under)                       3 days
         (c)    Beam (Soffits)                                 7 days
         (d)    Removal of prop under :
                (j) Slabs spaning upto 4.5m                    7 days
                (ii) Slabs spanning over 4.5m                  14 days
         (e)    Removal of props under beams and arches :
                (i) Spanning upto 6m                           14 days
                (ii) Spanning over 6 m                         21 days
                (iii) Spanning over 10m                        28 days

         In some case such as while using cements other than ordinary portland
         cement or when conditions are not normal, it may be necessary to estimate
         the strength of concrete at the time of removal of form work. Cubes if they
         are cast to determine the strength of concrete at the time of removal of form
         work, should be cured alongwith the structure and not under standard
         conditions envisaged for sampling and strength tests of concrete. For rapid
         hardening cements 3/7 of the periods given for ordinary Portland cement will
         be normally sufficient, except that a minimum period of 24 hours is required.
         Due regard is to be given to curing methods to be employed before the form
         work is removed.
         When controlled concrete of M20 and more strength is used, the forms of
         slabs may be removed when concrete has generated strength equal to
         double the stresses generated by the dead load plus live load of 200 Kg/m2.
         In any case this period shall not be less than 96 hours on placing last batch
         concrete in the slabs.

52       SEQUENCE OF REMOVAL OF FORMS
52.1     In respect of complicated structure referred to in para 63 the sequence of
         removal of forms may be obtained from design office.

53       HANDLING AND CONVEYING
53.1     The method of transporting and placing concrete shall be approved by the
         Engineer-in-Charge. Concrete shall be so transported and placed that no
         contamination, segregation or loss of constituent materials takes place.
         Concrete shall be transported as rapidly as practicable without any slump loss
         exceeding 25mm or a loss in air content more than 1% before the concrete is
         placed in the works.
53.2     Where the time of haul exceeds 20 minutes, mixed concrete shall be
         transported under cover protected from evaporation.

54       BUCKETS
54.1     Buckets used for conveying concrete shall be capable of prompt discharge of
         low slump, lean mix concrete of controlled quantities without splashing or
         segregation and shall be of such capacity that there is no splitting of batches
         in loading buckets. Buckets shall be of the bottom dump type, permitting an
         even controlled flow into the forms or hopper without undue splashing or


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         segregation. Cars, trucks and ships shall be designed to facilitate uniform
         delivery rather than quick dumping.

55       CHUTES
55.1     Chutes used for conveying concrete shall be of such type and shape as to
         ensure a steady uniform flow of concrete in a compact mass without
         separation or loss of ingredients and shall be protected from wind and such
         where necessary to protect loss of slump by evaporation and shall be
         furnished with a discharge hopper. The free fall or drop of concrete shall be
         limited to 150 cm. The chute sections shall be made of or lined with metal and
         all runs shall have approximately some slopes not flatter than 1 vertical to 2 ½
         horizontal. The required consistency of concrete shall not be changed in
         order to facilitate chuting. If it becomes necessary to change the consistency,
         the concrete mix will be completely redesigned. Wherever there is a free fall
         within the conveying system, suitable baffle plates, splash boards or down
         spouts shall be provided to prevent segregation, splashing or loss of
         ingredients. Whenever it is necessary to hold the discharge of a chute more
         then three metre above the level of the fresh concrete, a flexible down spout
         will be used to break the fall and confine the flow. The lower end of the spout
         shall be held close to the place of deposit wherever depositing is intermittent,
         a discharge hopper will be provided. All chutes shall be thoroughly cleaned
         before and after each run. All wash water and debris shall be washed outside
         the forms.

56       PUMPING
56.1     Where concrete is permitted to be conveyed into place by the application of
         pressure, the pump and piping shall be suitably designed and shall be of
         adequate capacity for the work. Pumping shall be permitted only for
         conveying concrete containing aggregates less than 7.5cm maximum size.
         The operation of the pumping system shall be such that a continues stream of
         concrete, without air pockets or interruptions, is delivered. At the end of the
         run, all concrete remaining in the pipe line shall be rejected in such a manner
         as to avoid any segregation or lack of uniformity. The pump and line shall be
         thoroughly cleaned and all wash water and debris wasted.

57       BELT CONVEYORS
57.1     Where transportation by means of belt conveyors is permitted, a steady,
         uniform flow of concrete shall be maintained without any segregation of piling
         up on steep inclines or at transfer points. The conveyor shall be covered to
         prevent damage by rain, loss of heat during cold weather, evaporation or
         heating by the direct rays of the sun, or other deterioration of the concrete.
         Concrete shall not be discharged directly into the forms, unless the discharge
         end of the conveyor or pipe can be readily moved about with in the forms so
         as to place the concrete in even layers as specified under Clause 61.
         Otherwise, suitable hoppers shall be provided, from which the concrete shall
         be dumped in place by means of buckets and shorts chutes or spouts.

58       CLEANING AND WASHING OF EQUIPMENTS
58.1     Equipment used for transporting concrete from the mixer to the form shall be
         maintained free from deposit of stiff concrete and leakage of mortar. Batch
         containers, transit mixers, chutes, concrete pumps, pipe lines and discharge



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         hoppers shall be thoroughly cleaned after each run and wash water and
         debris wasted outside the forms.

59       PREPARATION FOR PLACING CONCRETE
59.1     Before depositing any concrete for the next lift or pour, the forms shall not be
         retightened. The surface of contact shall be allowed to dry out between
         placing successive lifts of concrete. The top of the previously deposited
         concrete shall be thoroughly cleaned and prepared as specified under para
         65.

60       ROCK FOUNDATION
60.1     All rock surfaces against which concrete is to be placed shall be clean and
         free from mud, dirt, oil, organic deposits, or other foreign material which may
         prevent a tight bond between the rock and concrete. Seams shall be cleaned
         to a suitable depth and to firm rock along the side. Where excavation
         methods or the natural rock strata do not leave a sufficiently rough surface of
         contact, the bed shall be roughened by cutting steps, grooves, trenches, or
         keyways into the solid rock. Scaly coatings, hardened grout or concrete,
         construction debris, and other objectionable materials shall be removed.
         Seepage shall be properly controlled and diverted. The foundation bed and
         sides shall be carefully cleaned with stiff brooms, picks, jets of water and air
         applied at high velocity or other equally effective means, followed by
         thorough washing. After washing and before placing any concrete, water shall
         be removed from depressions and the rock surface shall be left uniformly
         damp. If any drilled hole is left in the foundation surface which is no longer
         needed, the holes shall be cleaned with air water jetting and filled up
         completely with cement slurry.

60.2     All flat surfaces shall then be coated with mortar about 1.5 cm thick in the
         case of concrete surfaces and 2 cm thick on rock surfaces. The water cement
         ratio for the mortar layer shall not exceed that for the regular concrete
         mixture, and the mortar shall be of such consistency that it can be spread
         evenly without flowing. It shall be thoroughly broomed and worked into all
         irregularities, cracks and crevices. The manner of spreading and working
         shall be such as not to cause any segregation, and concrete shall be placed
         immediately upon the fresh mortar before its initial set.

60.3     No concrete shall be deposited until the foundation has been inspected and
         approved. Where the rock is dry enough to absorb water from the mortar
         layer, it shall be soaked for at least 24 hours prior to placing to concrete.
         Detailed instructions shall be issued for preparing scaly or cracked
         foundations requiring special treatment or grouting.

60.4     On very rough or broken surface the first few batches of concrete may, if so
         required, contain only about one half the regular proportion of coarse
         aggregate.

61       EARTH OR SHALE FOUNDATIONS
61.1     In the case of earth or shale foundations, all soft or loose mud and surface
         debris shall be scraped and removed. The surface shall be moistened to a
         depth of about 15 cm to prevent the subgrade from absorbing water from the
         fresh concrete. Just before placing the concrete the surface of the earth shall
         be tamped or otherwise consolidated sufficiently to prevent contamination of


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         concrete during placing. In general, concrete shall be deposited only upon
         material lying in natural undisturbed state.

61.2     Foundations of porous or free draining materials shall be thoroughly
         compacted by flushing and by subsequent tamping or rolling, if necessary.
         The finished foundation surface shall then be blanketed with a layer of tar
         paper or closely woven burlap carefully lapped and fastened down along the
         seams so as to prevent the loss of mortar from the concrete.

61.3     Unless otherwise specified, the under drainage system for all foundations
         shall be blanketed as specified under Clause 61.2.

62       PLACING OF CONCRETE
62.1     No concrete shall be placed until the place of deposit has been thoroughly
         inspected and approved by Engineer-in-Charge, all reinforcement, inserts and
         embedded metal properly secured in position and checked, and forms
         thoroughly wetted (except in freezing weather or oiled). Placing shall be
         continued without avoidable interruption while the section is completed or
         satisfactory construction joint made. The position and arrangement of
         construction joint shall be indicated by the designer.

62.2     If concreting is not started within 24 hours of the approval being given, it shall
         have to be obtained again from the Engineer-in-Charge.

62.3     During cold weather, concreting shall not be done when the temperature falls
         below 4.5o C. The concrete placed shall be protected against frost by
         suitable coverings. Concrete damaged by frost shall be removed and work
         redone. During hot weather, precautions shall be taken to see that
         temperature of wet concrete does not exceed 40o C.

63       SEQUENCE OF CONCRETE
63.1     In respect of complicated structures such as continuous bridges, balanced
         cantilever bridges, cantilevers canopies more than 3m, rigid framed
         structures, box type structures etc, the sequence of concreting must be
         stipulated in drawing. If this is not given in drawing it should be obtained from
         design office and concreting done accordingly.

64       WITHIN FORMS
64.1     Concrete shall be systematically deposited in shallow layers and at such rate
         as to maintain, until the completion of the unit, a plastic surface approximately
         horizontal throughout. Each layer shall be thoroughly compacted before
         placing the succeeding layer. In general, the thickness of layers shall not
         exceed the following limits:
         (a)      Vibrated mass concrete                 45 cm
         (b)      Hard compacted mass concrete           30 cm
         (c)      Reinforced concrete                    25 cm

64.2     The batches shall be deposited vertically in such a manner so as to avoid
         segregation, air pockets, or damage to other recently placed concrete. In so
         far as it is practicable, concrete shall be placed directly in its final position and
         shall not be caused to flow in a manner to permit or cause segregation.


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         Method and equipment employed in placing concrete will ensure that
         aggregate is not separated from the concrete mass.

64.3     In placing mass concrete in a lift, successive batching of concrete shall be
         placed in a systematic arrangement in order to avoid long exposure of parts
         of the live surface of a concrete layer. Wherever necessary, both the forms
         and reinforcement shall be protected shall be protected against splashing,
         and all accumulation of partially set, dried, or caked mortar which may impair
         the bond or show in the finished faces shall be removed and wasted before
         commencing concreting operations.

65       CLEANING JOINTS
65.1     When the work has to be resumed on a surface which has hardened, such
         surface shall be roughened. It shall then be swept clean so as to expose
         sound concrete surface. The method shall be by means of jets of air and
         water applied at high velocity with such additional roughening of the surface
         by means of stiff wire brushes as may be required. Brushing shall be done by
         jabbing and digging into the surface rather than by merely sweeping. The
         whole process shall be conducted in such manner as not to loosen the coarse
         aggregates but vigorously enough to expose a fresh clean cut concrete
         surface.

65.2     Immediately before depositing fresh concrete, the contact surface shall again
         be gone over and thoroughly washed to remove all debris and loose material.
         The final pick-up of loose materials shall be made near the centre of the joint
         and away from the outside edges of the masonry. Dry contact surfaces shall
         be kept saturated with water for not less than 24 hours, but all standing water
         shall be removed from depressions before spreading the layer of mortar or
         cement slurry.

65.3     For horizontal joints the surface shall be covered with a layer of mortar about
         10 to 15 mm thick. The mortar will have the same proportions of water, air
         entraining agent, cement and fine aggregate as the concrete mixture which is
         to be placed upon it. The water cement ratio of the mortar in places shall not
         exceed that of the concrete to be placed upon it, and the consistency of the
         mortar shall be suitable for being spread uniformly and worked thoroughly into
         all irregularities of the surface.

65.4     For vertical and inclined joints (surfaces) which can not be covered with
         mortar shall be given a heavy coat of neat cement grout, vigorously brushed
         into all interstices and hollows or neat cement slurry shall be applied on the
         surface before it is dry so as to provide the best possible conditions for bound
         and applied immediately before placing of the concrete.

65.5     Where the concrete has not fully hardened, all laitance shall be removed by
         scrubbing the wet surface with wire or bristle brush, care being taken to avoid
         dislodgement of particles of aggregate. The surface shall be thoroughly
         wetted and all free water removed. The surface shall then be coated with neat
         cement slurry. On this surface, a layer of concrete not exceeding 150mm in
         thickness shall first be placed and shall be well rammed against old work,
         particular attention being paid to corners and close spots; work thereafter
         shall proceed in the normal way.

65.6     Should the next lift be delayed the contact surface shall be kept wet and
         covered so as to minimize the evaporation of curing water which may cause
         an injurious coating on the joint. Where necessary all defective and

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         undesirable concrete shall be removed by chipping and picking by hand or, if
         so required, by wet sand blasting the top to a depth just sufficient to expose
         afresh, clean cut surface over the entire area, which shall then be thoroughly
         flushed with water. Every precaution shall be taken to afford suitable bond for
         the succeeding lift.

65.7     If from any cause, the working surface is left exposed until it has hardened to
         a considerable extent, it shall be left to set and cure for not less than 56 hours
         or longer if necessary until a strength greater than 35.21 g/cm2 (500 PSI) has
         been attained, before completing the lift. The surface thus, interrupted shall
         be treated in same manner in Clause 65.4.

65.8     Hardened surfaces of old masonry on which new concrete is to be placed,
         shall unless otherwise ordered, be prepared in the same manner as provided
         for rock foundations under Clause 60.

66       RATE OF PLACING
66.1     Concreting shall be continued without avoidable interruption until the structure
         or section is completed or until satisfactory construction joints can be made.
         Concrete shall not be placed faster than the placing crew can compact it
         properly. In placing concrete in thin members and columns precautions shall
         be taken against too rapid a placement which may result in movement or
         failure of the form due to excessive internal pressure. An interval of atleast 4
         and preferably 24 hours should elapse between the completion of columns
         and walls and the placing of slabs, beams or girders supported by them in
         order to avoid cracking due to settlement. All concrete shall be placed in
         approximately horizontal lifts not exceeding 150cm in thickness except to
         expedite the placing of embedded material. The interval between two lifts
         shall also be maintained as constant as possible, and the difference of
         elevation between any two adjacent blocks shall not be more than 900 cm
         and not less than 150 cm. A period of 5 days for 150 cm of concrete laid shall
         be allowed before the next pour unless heat dissipation methods warrant
         otherwise.

67       PLACING “PLUMS IN CONCRETE”
67.1     In mass concrete members, stone plums may be used, with a view to effect
         economy, in zones not subject to tensile stresses upto a maximum limit of 20
         percent by volume of concrete when specifically permitted by the Engineer-in-
         Charge. While placing plums, care shall be taken that clear distance between
         any two plums is not less than either the width or thickness of either of the
         plums of 15 cms whichever is more. No stone shall be closer than 30 cm to
         an exposed surface. The stones shall not be dropped in place, but each stone
         shall be laid and carefully embedded so as to avoid any injury to the forms or
         adjacent masonry and in such a manner that no planes of weakness or
         unnecessary seams occur in the structure.

67.2     During concreting, the first layer of concrete of the specified mix shall be laid
         to a thickness of at least two and a half times the thickness of the maximum
         size of plums to be used. The plums shall then be laid while the top portion of
         this concrete is still green but sufficiently stiff to prevent complete
         submergence of the plums under their own weight. These plums shall be
         about half embedded in the concrete and the remaining part exposed so as to
         form a key with the next layer of concrete. No plums shall be used for
         concrete laid under water.


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67.3     If plums of stratified stone are used, they shall be laid on their natural bed.
         Stones with concave faces shall be laid with the concave face upwards.

67.4     The thickness of the next and successive layers of concrete shall be at least
         twice that of the largest plum.

67.5     In placing mass concrete, the exposed area of fresh concrete shall
         maintained at the practical minimum by first building up the concrete in
         successive approximately horizontal layers to the full width of the block and to
         full height of the lift over a restricted area at the down stream and of the block
         and then continuing upstream in a similar progressive stages to the full area.
         The slopes formed by the unconfined upstream edges of the successive
         layers of concrete shall be kept as steep as practicable in order to keep its
         area minimum. Concrete along these edges shall not be vibrated until
         adjacent concrete in the layer is placed, except that it shall be vibrated
         immediately when weather conditions are such that the concrete will harden
         to an extent the late vibration may not fully consolidate and integrate it with
         more recently placed adjacent concrete.

67.6     In formed work, structural concrete placements shall generally be started with
         an over-sanded mix containing 20mm maximum size aggregate and an extra
         bag of cement per cubic metre and having a 125mm slump placed several
         centimeters deep on the joints at the bottom of the form. Concrete placement
         shall commence immediately thereafter.

67.7     If concrete is placed monolithically around opening having vertical dimensions
         greater than 0.6 metre, or if concrete in decks floor slabs, beams, girders, or
         other similar parts of a structure is placed monolithically with supporting
         concrete, the following instructions shall be strictly observed:
         (i)      Placing of concrete shall be delayed not less than one hour or more
                  than three hours at the top of openings and at the bottom of filets
                  under decks, floor slabs, beams, girders or other similar parts of
                  structures when fillets are specified and at the bottom of such
                  structures, members when fillets are not specified but in no case shall
                  the placing be delayed so long that the vibrating unit will not of its own
                  weight readily penetrate the concrete placed before the delay. When
                  consolidating concrete placed after the delay, the vibrating unit shall
                  penetrate or vibrate the concrete placed before the delay.
         (ii)     The last 0.6 metre or more of concrete placed immediately before the
                  delay shall be placed with as low slump as practicable and shall be
                  thoroughly compacted.
         (iii)    The surfaces of concrete where delays are made shall be clean and
                  free from loose and foreign materials when concrete placing is started
                  after the delay.
         (iv)     Concrete placed over openings and in decks, floors, beams girders
                  and other similar parts of structures shall be placed with as low slump
                  as practicable.
         (v)      Concrete should be deposited at or near to final portion in the
                  placement, eliminating the tendency to segregate when it has to flow
                  laterally into place, sloping surfaces, concrete should be placed at the
                  lower end of the slope first, progressing upward and thereby
                  increasing natural compaction of the concrete. High velocity discharge



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                  of concrete, which may cause segregation of the concrete should be
                  avoided.

68       LARGE BLOCKS
68.1     In placing concrete in large blocks, the work shall in general proceed from
         the low side so that the working face is never excessively steep nor long.
         However, for construction joints in dams/canals, the work shall proceed from
         the high side to the low side so as to maintain in upward slope in the
         downstream direction, unless construction joints are otherwise shown on the
         drawings. Under no condition shall the slope be so steep as to cause the
         concrete to flow without working, or to cause any segregation. The concrete
         shall be deposited as nearly as practicable in final position and shall not be
         piled up in large masses at any point and then pushed, shoveled, or vibrated
         into space for long distances. It shall be brought up evenly around all large
         openings, conduits, or embedded metal so as to minimize unequal pressure
         and avoid displacement. For large blocks of concrete in dams/canals and
         other massive structures, the sequence and rate of casting successive lifts
         and adjacent blocks shall be such as to facilitate the dissipation of the heat of
         hydration.

69       FISSURES
69.1     Where fissures in concrete are necessary to be produced (e.g. in bucket
         invert etc.) the use of fissure reinforcement concrete may be considered by
         the Engineer-in-Charge.

69.2     All concrete construction shall conform to the permissible tolerance and
         technical provisions as described in this section and to the detailed
         requirements of the following paragraphs. All structures shall be built in a
         workman like manner and to the lines, grades and dimensions shown in the
         drawings or prescribed by the Engineer-in-Charge. The location of all
         construction joints shall be subject to the approval of the Engineer-in-Charge.
         The dimension of each structure shown on the drawings will be subject to
         such changes as may be found necessary by the Engineer-in-Charge to
         adopt structures to the conditions disclosed by the excavation or otherwise.

70       REJECTED CONCRETE
70.1     All concrete of inferior quality shall be rejected and removed from the site of
         operations, if possible, before placing fresh concrete; where concrete has
         already been placed if, found inferior, it shall be dug out and removed from
         the forms. Any batch, too stiff for proper placement or in such a condition that
         it cannot be properly compacted, shall be removed.

71       CONCRETING WORK IN EXTREME WEATHER
         CONDITIONS
71.1     During hot or cold weather concreting should be done as per the procedure
         set out in IS:7861 Part I or Part II.

72       CONCRETE WORK UNDER WATER CONCRETING
72.1     When it is necessary to deposit concrete under water, the methods
         equipment, materials and proportions of the mix to be used shall be submitted


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         to and approved by the Engineer-in-Charge before the work is started. In no
         case shall such concrete be considered as “Design mix concrete”.

72.2     The concrete shall contain at least 10 percent more cement than that required
         for the same mix placed in the dry condition, the quantity of extra cement
         varying with conditions of placing. The volume or mass of the coarse
         aggregate shall be not less than one and a half times, nor more than twice
         that of the fine aggregate. The materials shall be so proportioned as to
         produce a concrete having a slump of not less than 100mm, and not more
         than 180mm.

72.3     Coffer-dams or forms shall be sufficiently tight to ensure still water if
         practicable, and in any case to reduce the flow of water to less than 3m per
         minute through the space into which concrete is to be deposited. Coffer dams
         or forms in still water shall be sufficiently tight to prevent loss of mortar
         through the walls. Dewatering by pumping shall not be done while concrete is
         being placed or until 24 hours thereafter.

72.4     Concrete shall be deposited continuously until it is brought to the required
         height. While depositing, the top surface shall be kept as nearly level as
         possible and the formation of seams avoided. The methods to be used for
         depositing concrete under water shall be one of the following;
         (a)      Tremie : When concrete is to be deposited under water by means of a
                  tremie, the top section of the tremie shall have a hopper large enough
                  to hold one entire batch of the mix or the entire contents of the
                  transporting bucket if any. The tremie pipe shall be not less than
                  200mm in diameter and shall be large enough to allow a free flow of
                  concrete and strong enough to withstand the external pressure of the
                  water in which it is suspended, even if a partial vaccum develops
                  inside the pipe. Preferably, flanged steel pipe of adequate strength for
                  the job should be used. A separate lifting device shall be provided for
                  each tremie pipe with its hopper at the upper end. Unless the lower
                  end of the pipe is equipped with an approved automatic check valve,
                  the upper end of the pipe shall be plugged with a wadding of the
                  gunny sacking or other approved material before delivering the
                  concrete to the tremie pipe through the hopper, so that when the
                  concrete is forced down from the hopper to the pipe, it will force the
                  plug (and alongwith it any water in the pipe) down the pipe and out of
                  the bottom end, thus establishing a continuous stream of concrete. It
                  will be necessary to raise slowly the tremie in order to cause a uniform
                  flow of the concrete, but the tremie shall not be emptied so that water
                  enters the pipe. At all times after the placing of concrete is started and
                  until all the concrete is placed, the lower end of the tremie pipe shall
                  be below the top surface of the plastic concrete. This will cause the
                  concrete to build up from below instead of flowing out over the surface
                  and thus avoid formation of laitance layers. If the charge in the tremie
                  is lost while depositing, the tremie shall be raised above the concrete
                  surface, and unless sealed by a check valve, it shall be replugged at
                  the top end, as at the beginning, before refilling for depositing
                  concrete.
         (b)      Drop Bottom Bucket : The top of the bucket shall be covered with a
                  canvas flap. The bottom doors shall open freely downward and
                  outward when tripped. The bucket shall be filled completely and
                  lowered slowly to avoid backwash. The bottom doors shall not be
                  opened until the bucket rests on the surface upon which the concrete


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                  is to be deposited and when discharged, shall be withdrawn slowly
                  until well above the concrete.
         (c)      Bags of at least 0.028 cum capacity of jute or other coarse cloth shall
                  be filled about two thirds full of concrete, the spare end turned under
                  so that bag is square and securely tied. They shall be placed carefully
                  in header and stratcher courses so that the whole mass is inter
                  locked. Bags used for this purpose shall be free from deleterious
                  materials.
         (d)      Grouting : A series of round cages made from 50 mm mesh of 6mm
                  steel and extending over the full height to be concreted shall be
                  prepared and laid vertically over the area to be concreted so that the
                  distance between centres of the cages and also to the faces of the
                  concrete shall not exceed one metre. Stone aggregate of not less than
                  50mm nor more than 200mm size shall be deposited outside the steel
                  cages over the full area and height to be concreted with due care to
                  prevent displacement of the cages.

72.5     A stable 1:2 cement sand grout with a water cement ratio of not less than 0.6
         and not more than 0.8 shall be prepared in a mechanical mixer and sent
         down under pressure (about 0.2 N/mm2) through 38 to 50 mm diameter pipes
         terminating into steel cages, about 50mm above the bottom of the concrete.
         As the grouting proceeds, the pipe shall be raised gradually up to height of
         not more than 600mm above its starting level after which it may be withdrawn
         and placed into the next cage for further grouting by the same procedure.

72.6     After grouting the whole area for a height of about 600mm, the same
         operation shall be repeated, if necessary, for the next layer of 600mm and so
         on.

72.7     The amount of grout to be sent down shall be sufficient to fill all the voids
         which may be either ascertained or assumed as 55 percent of the volume to
         the concreted.

72.8     To minimize the formation of laitance, great care shall be exercised not to
         disturb the concrete as far as possible while it is being deposited.

73       COMPACTING
73.1     Concrete shall be thoroughly compacted by means of suitable tools during
         and immediately after depositing. The concrete shall be worked around all
         reinforcement, embedded fixtures, and into the corners of the forms. Every
         precaution shall be taken to keep the reinforcement and embedded metal in
         proper position and to prevent distortion.

73.2     compacting shall include rodding, spading, tamping, vibrating, treading, and
         such other operations except finishing, as are necessary to consolidate and
         mould the concrete properly. The rate of placing mass concrete or reinforced
         concrete in thin sections, whether mechanically or by manual labour, shall be
         clearly defined.

73.3     Accumulation of water on the surface due to bleeding, or other causes taking
         place during compacting shall be stopped as much as possible by
         adjustments in the mix. All free water on the surface shall be removed by
         sponging or mopping. Under no circumstances shall such accumulation of



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         water be covered up with concrete or dry concrete used to soak up excess
         water.

73.4     Unless other wise permitted, all concrete shall be compacted by mechanical
         vibration. The number and type of vibrators shall be subject to the approval of
         the Engineer-in-Charge. In general, only vibrators of the internal type shall be
         used. However in inaccessible places in the forms, where spading, rodding,
         or forking is impracticable, the concrete may be gently worked into place and
         compacted by light vibrating or hammering the forms.

74       VIBRATING
74.1     Wherever practicable, concrete shall be internally vibrated within the forms, or
         in the mass, in order to increase the plastically and to compact effectively to
         improve the surface texture and appearance, and to facilitate placing of the
         concrete.

74.2     The intensity and duration of vibration shall be sufficient to cause complete
         settlement and compaction without any stratification of the successive layers
         or separation of ingredients. Preliminary experiments in vibrating shall be
         conducted under actual conditions of mix and placement in order to determine
         the optimum duration and method of vibration, as well as to develop the
         necessary skill.

74.3     Vibration shall be continued until the entire batch melts to a uniform
         appearance and the surface just starts to glisten. A minute film of cement
         paste shall be discernible between the concrete and the forms and around the
         reinforcement. Over vibration causing segregation, unnecessary bleeding or
         formation

75       INTERNAL TYPE VIBRATORS
75.1     Mass concrete shall be thoroughly compacted with the side of high frequency,
         mechanical vibrators of the interval type having not less then 3600 and
         preferably more than 5000 impulses per minute. Immediately after depositing
         the concrete, the vibrators shall be inserted into each pile, operated from 10
         to 20 seconds in one spot and then moved to another not over 90cm (or 3 ft.)
         away. The operation shall be repeated over until the entire mass is thoroughly
         compacted and the pile, levelled down. Equal attention shall be paid to the
         edge of the pile and to the centre. A sufficient number of two man vibrators
         shall be used to compact each batch properly before placing the next one. A
         sufficient number of reserve vibrators in good conditions shall be kept on
         hand at all times so as to assure that there is no slackening or interruption in
         compacting.

75.2     The use of flexible shaft vibrators, if permitted, shall closely follow special
         instructions issued for the purpose.

75.3     Internal vibrators shall be allowed to penetrate as deeply as possible under
         their own weight and shall so consolidate the successive layers as to break
         up effectually all strata or seams. The vibrators shall be inserted and
         withdrawn slowly in such manner as not to leave voids in the plastic concrete.
         The entire operation shall be conducted in a systematic manner and each
         course or layer vibrated uniformly. The method of dumping or depositing the
         loads shall be so arranged as to keep the vibrators working continuously
         during placing operations. The courses shall be kept approximately level, and


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         the concrete even when deposited in thin layers, shall be as stiff as can be
         satisfactorily worked. However, concrete for which a slump greater than 10
         cm is specified shall not be vibrated unless otherwise ordered. Care shall be
         taken not to disturb a set of partially set layer. The vibrators shall be held
         vertical as far as possible.

75.4     Under no conditions shall internal vibrators strike the face of the forms, nor
         shall reinforcement steel or embedded metal be jarred with sufficient force to
         impair the bond between the concrete and the metal.

76       EXTERNAL TYPE VIBRATORS
76.1     Wherever so required, platform vibrators shall be used to embed all large
         stone or cobble projecting above the top of the lift, but such vibrators shall be
         used with caution and operated only in such manner for a depth of about
         30cm shall be thoroughly vibrated. Particular care shall be taken in making
         keyways and shear grooves. Where a raised key is required, the form shall be
         filled to overflowing and a platform vibrator used to compact the concrete and
         bond the key to the body of the lift.

76.2     Form vibrators shall be permitted only for special purpose specified under
         Clause 73.3 and extreme care shall be exercised to avoid pumping air into
         the concrete.

77       SURFACE VOIDS
77.1     Large voids or air pockets, which may be left in the permanently exposed
         faces of the structure by vibration, shall be removed systematically spading
         the face in the following manner. Wherever practicable, a motor driven, slowly
         revolving, square steel rod shall be held in a vertical position and moved
         slowly back and forth in short intervals along the entire face. Care shall be
         taken to avoid prolonging such spading to the point of leaving excess mortar
         in the face.

78       GREEN CUTTING :
78.1     The surface of the respective lift shall be thoroughly green cut with an air
         water jet. Green cutting is usually done 8 to 12 hours after the top surface of a
         concrete lift had been completed and sufficiently hardened. The actual time
         for taking up the green cutting operation shall depend upon the following
         factors.
       a)    Concrete placement temperature
       b)    .Atmospheric temperature.
       c)    Concrete mix, and
       d)    Slump.

78.2     The air water jet will remove the thin surface film of latency and grout to
         expose clean surface.

78.3     Green cutting, if done at the proper time, shall yield very good results. When
         started too early, it shall result in over cutting and removing too much mortar.
         It is also liable to loosen the aggregate particles and leaving too poor a
         surface to bind the fresh concrete. On the other hand, if green-cutting is
         delayed too long, the cutting action of the air and water jet would be


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         ineffective for proper removal of latency. It therefore, requires much greater
         care and judgment for proper use at proper time.

78.4     Skill of jet Operator : Besides determining the proper time for initiating green
         cutting, the process will require constant attention on the part of the air water
         jet operator. By correct manipulation of the high velocity air-water jet, a
         trained operator can ensure the removal of the thin surface film of laitance
         and grout effectively and at the same time, leaving, the aggregate, already
         embedded in the mortar, undisturbed.

78.5     Proper Air-water Gun: In addition to the skill of the jet operator, a proper air
         water gun is also a vital requirement for effective green-cutting, the issuing
         nozzle must be about 460 mm. (18inches) long to ensure the requisite cutting
         force close to the concrete surface.

78.6     Quantum of Compressed Air and Water :- For effective green cutting, it is
         essential that the air pressure should be around 6.33 to 7.03 kg/cm2. It
         should not be allowed to fall below 6.33Kg/cm2. The water pressure, of
         course, should be sufficient to bring the water into effective influence of the air
         pressure. As an approximate estimate, the quantity of compressed air
         required by the green-cutting gun is 2 cubic meters per minute and the
         quantity of water is 60 gallons (273 Liters) per minute.

78.7     An important aspect to be taken note of is that green-cutting as an exclusive
         operation shall be fully useful only if the next lift of concrete is placed within 3
         to 4 days(or a maximum of 5 days of the placement of the previous lift. if
         there be a delay in concrete placement beyond this period, the laitance will
         come up to the concrete surface again at some places removal of such
         laitance shall then be not possible by the ordinary green-cutting operation
         along light sand blasting of even the green-cut lifts shall have to be resorted
         to. However, if there is excessive delay in concrete placement, it will require
         either “Wet sand” blasting of the application of high pressure “water blaster”to
         remove the laitence for effective binding with the fresh concrete. The effect to
         achieve this will be considerably less if green cutting has already been done.

79       SAND BLASTING :
               Sand blasting is the process of roughening and cleaning the surface of
               old and set concrete by means of coarse sand and air applied under
               pressure of 6.33 to 7.03 Kg/Cm2 through a nozzle, so as to erode the
               laitence and grout from the old concrete. Sand blasting of rock is also
               done so that concrete may be placed on or against a clean surface of
               rock as required according to specifications.
               There are two types of sand blasting, namely “wet sand blasting” and
               “dry sand blasting” In wet sand blasting water is also used along with
               sand and air under pressure, while in the later, only sand and air under
               pressure are used. Normally the concrete and rock surface etc., are wet
               sand blasted to keep down the dust.
               The percentage of different sizes of sand particles for efficient sand
               blasting shall be as follows.
       --------------------------------------------------------------------------------------------------
                             Size                                                       Percentage
         --------------------------------------------------------------------------------------------------
         8 mesh per inch (25.40 Millimeters)                                            26
         16 mesh per inch (25.40 Millimeters)                                           30

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TECHNICAL SPECIFICATION

         30 mesh per inch (25.40 Millimeters)                                          23
         50 mesh per inch (25.40 Millimeters)                                          21
       ---------------------------------------------------------------------------------------------------

79.1     For effective sand blasting, it is essential that pressure of air should be
         between 6.33 to 7.03 Kg/cm2. Sand blasting becomes ineffective. if sand
         having large percentage of fines is used, it will not provide the requisite
         cutting power and the whole effort goes waste. A good quality well graded
         sand (sand-blast-sand) is needed for achieving the objective of sand blasting.

79.2     High pressure Water Blasters Green cutting is far cheaper then sand blasting.
         Proper quality sand (Known as sandblast sand ) is most expensive item and
         special efforts are needed to arrange such sand. A high pressure water
         blaster offers a workable alternative to sand blasting.

79.3     Summary : Green cutting offers the most economical methodology in the
         preparation of good construction joints. It has, however, to be initiated at the
         proper time and with a proper air- water gun to yield the best results. It is far
         cheaper than sand blasting. If a delay of more than 3 to 5 days is anticipated
         in placing the concrete over the previous lift the concrete surface of the lift
         should be properly “green cut” and thereafter (say one day prior to placement
         of concrete) it should be light sand blasted or water blasted in order to
         remove the “re-appeared” laitance.

80       OTHER REQUIREMENTS OF CONCRETE
         CONSTRUCTIONS:
80.1     All concrete construction shall conform to the permissible tolerances and
         technical provisions as described in the section. All structures shall be built
         in a workman like manner, to the lines grades and dimensions shown in the
         drawings or as prescribed by the Engineer-in-charge. The location of all the
         construction joints shall be subject to the approval of the Engineer-in-charge.
         The dimensions of each structure shown on the drawings shall be subject to
         such changes as may be found necessary by the Engineer-in-charge. to
         adopt the structure to the conditions disclosed by the excavation.

81       CONCRETE IN VARIOUS COMPONENTS OF BRIDGES,
         UNDER TUNNELS, AQUEDUCTS ETC.,
81.1     Expansion joints shall be constructed as shown on the drawings or as
         directed. Premoulded bituminous fibre type expansion joint material shall be
         placed in the expansion joints. Lighting recesses shall be constructed in the
         parapets as directed by the Engineer-in-charge. Open joints or false joints
         shall be constructed as shown on the drawings or as directed by the
         Engineer-in-charge. Preformed expansion joint filler shall be placed in the
         road way and side walls where shown on the drawings or as directed by the
         Engineer-in-charge.

82       EMBEDMENT IN CONCRETE:
82.1     In some of the locations of structures, a few conduit openings shall have to
         be provided through RCC/PCC as shown in the drawings. Placement of
         concrete shall be suitably carried out around such conduits or openings. No
         extra claim shall be entertained.



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TECHNICAL SPECIFICATION

83       CURING OF CONCRETE
83.1     All concrete shall be cured by water in accordance with the requirement of
         Clause 85 or membrane curing in accordance with the requirements of
         Clause 86 of this clause. Concrete surfaces to be painted shall not be cured
         by membrane curing.

84       CURING OF UNFORMED SURFACES AND PIERS
84.1     The unformed top surfaces of walls and piers shall be moistened by covering
         with water saturated material or by other effective means as soon as the
         concrete has hardened sufficiently to prevent damage by water. These
         surfaces and steeply sloping and vertical formed surfaces shall be kept
         completely and continuously moist, prior to and during from removal, by water
         applied on the unformed top surfaces and allowed to pass down between the
         forms and the formed concrete faces. This procedure shall be followed by the
         specified water curing and membrane curing.

85       WATER CURING
85.1     Concrete cured with water shall be kept wet for at least 14 days immediately
         following placement of the concrete or until covered with fresh concrete by
         covering with water saturated material or by a system of perforated pipes,
         mechanical sprinklers or porous hoses or by any other suitable method, which
         will keep all the surfaces continuously (not periodically) wet. The period of 14
         days specified above shall be increased to 21 days when pozzolana has been
         used in the concrete as part replacement of cement.

86       MEMBRANE CURING
86.1     Membrane curing shall be by application of a suitable type of white pigmented
         curing compound which forms a water retaining membrane on the surface of
         concrete, provided that on concrete surfaces which will be permanently
         exposed to view clear curing compound may be required. Curing compound
         shall be applied to the concrete surfaces by spraying on one coat to provide a
         continuous uniform membrane overall area, with a maximum coverage per
         litre as prescribed by the manufacturer according to the roughness of the
         surface to be covered. If necessary to cover the surface adequately a second
         coat of curing compound shall be applied by spraying at right angles to the
         direction at which first coat was applied. Mortar encrustation and fins on
         surface for which finish F-4 is specified shall be removed prior to application
         of curing compound. Curing compound shall be applied to all areas of
         concrete surfaces except that those parts with surface imperfections shall be
         omitted until repaired.

86.2     When curing compound is to be used on formed concrete surfaces,
         application of the compound shall commence immediately after the finishing
         operations are completed.

86.3     When curing compound is to be used on formed concrete surfaces the
         surface shall be moistened with light spray of water immediately after the
         forms are removed, and shall be kept wet until the surfaces will not absorb
         more moisture. As soon as the surface film of moisture disappears but while
         the surface still has a damp appearance, the curing compound shall be
         applied. There must the ample coverage with the compound at edges,
         corners and rough spot of formed surfaces. After application of curing

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TECHNICAL SPECIFICATION

         compound has been completed and the coating is dry to the touch, any
         required repair of concrete surface shall be performed. Each repair after
         being finished, shall be moistened and coated with curing compound in
         accordance with the foregoing requirements.

86.4     Traffic and other construction operations shall be such as to avoid damage to
         coatings of curing compound for a period of not less than 28 days after
         application of the curing compound. Where it is impossible because of
         construction operations to avoid traffic over surfaces coated with curing
         compound, the membrane shall be protected by a covering of sand or earth
         not less than 25mm in thickness or by other effective means. The protective
         covering shall not be placed until the sealing membrane is completely dry.
         Any sealing membrane that is damaged or that peels from concrete surfaces
         within 28 days after application, shall be repaired without delay.

86.5     Curing compound if used, shall be of approved quality.

87       FINISHING OF CONCRETE SURFACE
87.1     Allowable deviations from plumb or level and from the alignment, profile
         grades and dimensions shown on the drawings are defined as “tolerance” and
         are to be distinguished from the irregularities in finish as described herein.
         The tolerance in concrete construction are specified in para 7.18.

87.2     The classes of finish and requirements for finishing of concrete surface shall
         be as shown on the drawings or as hereinafter specified. In the event of
         finishing not being definitely specified herein or on the drawings the finishes
         to be used shall be as directed. Finishing of concrete surfaces shall be
         performed only by skilled workmen.

87.3     Concrete surfaces will be tested where necessary to determine whether
         surface irregularities are within the limits hereinafter specified.

87.4     Surface irregularities are classified as “abrupt” or “gradual”. Offset caused by
         displaced or misplaced from sheathing or lining or from sections or by loose
         knots or otherwise defective form timber will be considered as abrupt
         irregularities and will be tested by direct measurements. All other irregularities
         will be considered as gradual irregularities and will be tested by use of
         template, consisting of a straight edge or the equivalent thereof for curved
         surfaces. The length of the template will be one and a half metres for testing
         of formed surfaces and three metres for testing unformed surfaces.

87.5     The classes of finish for formed concrete surfaces are designated by one of
         the symbols F1, F2, F3 and F4. Bag rubbing or sand blasting will not be
         required on formed surfaces. Grinding will not be required on formed
         surfaces, other than that necessary for the repair of surface imperfections.
         Unless otherwise specified or indicated on the drawings, the classes of finish
         which will apply are as follows :

87.6     Finish F1 : This finish is applied to surfaces where roughness is not
         objectionable, such as those upon or against which fill material, masonry or
         concrete will be placed, the upstream face of the dam that will permanently be
         under water or surfaces that will otherwise be permanently concealed. The
         surface treatment shall be repaired of defective concrete, correction of
         surface depressions deeper than 25mm and filling of tie rod holes. Form
         sheathing shall not leak mortar when the concrete is vibrated. Forms may be
         built with a minimum of refinement.

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TECHNICAL SPECIFICATION

87.7     Finish F2 : This finish is required on all permanently exposed surface for
         which other finishes F3 and F4 are not specified, such as in outlet works and
         open spillways, bridges and retaining walls not prominently exposed to public
         view and in the galleries and adits in the dam, except whre F1 finishes are
         permitted forms shall be built in a workman like manner to the required
         dimensions and alignment, without conspicuous off sets of bulge surface,
         irregularities, shall not exceed 5mm for abrupt irregularities and 10mm for
         gradual irregularities measured from a 1.5m template.

87.8     Finish F3 : This finish is designated for surfaces of structures prominently
         exposed to public view where appearance is of special importance. This shall
         include parapets, railings and decorative features on the dam and bridge. To
         meet the requirements for the F3 finish, forms shall be built in a skillful,
         workman like manner, accurately to dimensions. There shall be no visible
         offsets, bulges or misalignment of the concrete. At construction joints the
         forms shall be tightly set and securely anchored close to the joint. Surface
         irregularities shall not exceed 3 mm for abrupt irregularities and 5mm for
         gradual irregularities measured from a 1.5 m template.

87.9     Finish F4 : This finish is required for formed concrete surfaces at the spillway
         crest, glacis and bucket and inside sluices where accurate alignment and
         evenness of surface are essential for prevention of destrictive effects of water
         action. The forms must be strong and held rigidly and accurately to the
         prescribed alignment. For warped surfaces, the forms shall be built up in
         sections cut to made right, smooth form surface after which the form surfaces
         are dressed and sanded to the required curvature.

87.10 When measured as described in this clause, gradual irregularities shall not
      exceed 5mm. Abrupt irregularities will not be permitted. The formations of air
      holes on the surface of the concrete designated to receive finish shall be
      minimized and where such air holes are found, they shall be repaired in
      accordance with relevant section.

88       CLASSES OF FINISH FOR UNFORMED SURFACES
88.1     General : The classes of finish for unformed concrete surfaces are
         designated by the symbols U1, U2, U3 and U4. Unless otherwise specified or
         indicated on the drawings these classes of finish shall apply as follows.

88.2     Finish U1 : This finish applies to unformed surfaces that will be covered by fill
         material, masonry or concrete, or where a screeded surface finish meets the
         functional requirements. Finish U1 is also used as the first stage of finishes
         for U2 and U3. Finishing operations shall consist of sufficient leveling and
         screeding to produce even uniform surfaces. Surface irregularities measured
         as described in this section shall not exceed 10 mm.

88.3     Finish U2 : This is a floated finish and applies to all out door unformed
         surfaces not specified to receive finishes U1 or U3. It may be used for such
         surfaces as of spillways and aprons.

88.4     Finish U2 is also used as the second stage of finish for U3. Floating may be
         performed by use of hand or power driven equipment. Floating shall be
         started as soon as the screeded surface has stiffened sufficiently to prevent
         the formation of laitance, and shall be the minimum necessary to produce
         surface that is free from screed marks and is uniform in texture. If finish U3 is
         to be applied floating shall be continued until a small amount of mortar without
         excess water is brought to the surface, so as to permit effective trowelling.

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TECHNICAL SPECIFICATION

         Surface irregularities measured as described in this section shall be tolled
         down where shown on the drawing or as directed.

88.5     Finish U3 : This is a trowelled finish and may be specified for tops of
         parapets prominently exposed to view, and conduit invert immediately
         downstream of regulating gates and valves. When the floated surface has
         hardened sufficiently to prevent excess of fine material from being drawn to
         the surface steel trowelling shall be started. Steel trowelling shall be
         performed with firm pressure such as will be started. Steel trowelling shall be
         performed with firm pressure such as will flatten the sandy texture of the
         floated surface and produce a dense uniform surface free from blemishes and
         trowel marks. Surface irregularities, measured as described in relevant part of
         this section, shall not exceed 5mm. Where a hard steel trowelled finish is
         specified the regular U3 finish shall be trowelled again after the surface has
         nearly hardened using firm pressure and trowelling until the surface is hard
         and has a slightly glossy appearance.

88.6     Finish U4 : This is a steel trowelled finish similar to finish U3 except that light
         surface pitting and light trowel marks such as obtained from the use of
         machine trowelling or lining machines will be acceptable, provided the surface
         irregularities do ot exceed the limits specified for finish U3.

88.7     Unformed surfaces which are nominally level shall be sloped for drainage as
         shown on the drawings or as directed. Unless the use of other slopes or level
         surface is indicated on the drawings, narrow surface such as tops of
         parapets, tops of walls and kerbs shall be sloped approximately one cum per
         30 cm of width, broader surface such roadways, platform and decks shall be
         sloped approximately half centimeter per 30 cm of width.

89       REPAIRS OF CONCRETE
89.1     Repairs of concrete shall be performed by skilled workers and in the presence
         of an Engineer-in-Charge. All imperfections on the concrete surface as
         necessary to produce surfaces that conform with requirements of para 7.15
         on formed concrete shall be completed as soon as practicable after removal
         of forms and within 24 hours after removal of forms. Concrete that is
         damaged from any cause and concrete that is honey combed, fractured or
         otherwise defective and concrete which because of excessive surface
         depressions excavated and built up to bring the surface to the prescribed
         lines, shall be removed and replaced by dry pack mortar or concrete as
         hereinafter specified. Where bulges and abrupt irregularities protrude outside
         the limits specified in the Clause 87 on “Finishes & finishing of concrete
         surface”, the protrusions shall be reduced by chiseling and grinding so that
         the surfaces are within the specified limits.

89.2     Dismantling of a part of hardened concrete of a structural element must not
         be done by hammering since this is likely to crack adjoining good concrete.
         This should be done slowly by pointed chisel or mechanically operated tool
         preferably by a skilled mason.

89.3     Before repairs are commenced, the methods proposed for the repair shall be
         approved by the Engineer-in-Charge. Routine curing should be interrupted
         only in the area of repair operations.




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TECHNICAL SPECIFICATION

90       METHODS OF REPAIRS
90.1     For new works four methods are used.

91       DRY PACK METHOD
91.1     This method should be used for holes having a depth nearly equal to or
         greater than the least surface dimensions; for cone bolt, she bolt and grout
         insert holes and narrow slots cut for the repair of cracks. Dry pack should not
         be used for relatively shallow depressions where lateral restraint can not be
         obtained for filling in back of considerable lengths of exposed reinforcements;
         nor filling holes which extend entirely through the wall, beam, etc.

92       CONCRETE REPLACEMENT METHOD
92.1     Concrete replacement should be used when holes extend entirely through the
         concrete section; when holes in unreinforced concrete are more than 1000
         sq. cm in area and 100 cm or more in depth; and in holes in reinforced
         concrete are more than 500 sq. cm in area and deeper than the reinforcement
         steel.

93       MORTAR REPLACEMENT METHOD
93.1     This should be used for holes too wide to dry pack and too shallow for
         concrete replacement and for all comparatively shallow depressions, large
         and small, which extend more deeper than far side of the reinforcement bars
         nearest the surfaces.

94       EPOXIES METHOD
94.1     A thermosetting plastic known as epoxy can be used as a bonding medium
         wherever long time curing of conventional concrete can not be assured. Also
         epoxy mortars of fine sand as well as plain epoxy are suitable for concrete
         repair work and should be used whenever very thin patches are to be placed
         for immediate re-use of the area is required or where moist curing can not be
         effectively accomplished. Preparation for epoxy bonded repairs should in
         general be identical to that for other concrete repairs except that every effort
         should be made to provide surfaces which are thoroughly dry. Drying of the
         immediate surface for at least 24 hours and warming to temperature between
         18o C to 27o C are essential for proper application of epoxy bonded repaired.
         Preparation for the use of epoxy mortars should include thorough cleaning
         and drying of the areas to be repairs. A wash of dilute 1:4 muriatic acid rinsing
         with clean water and subsequent drying is desirable where feasible, if acid
         wash is not feasible, preparation may be accomplished as for other concrete
         repairs with final clean up being by means of sand blast method, followed by
         air water jet washing and thorough drying. Epoxy repairs shall be carried out
         only by trained personnel.

95       PREPARATION OF CONCRETE FOR REPAIR
95.1     All concrete of questionable quality should be removed. It is better to remove
         too much concrete than too little because affected concrete generally
         continues to disintegrate and while the work is being done it costs but little
         more to dismantle to ample depth. Moistening, cleaning, surface drying and
         complete curing are of utmost importance when making repairs which must


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TECHNICAL SPECIFICATION

         be thoroughly bounded, water tight and permanent. Surface between trimmed
         holes should be kept continuously wet for several hours, preferably overnight
         prior to placing new concrete immediately before placement of the filling, the
         holes should be cleaned so as to leave a surface completely free of chipping
         dust, dried grout and all other foreign materials. A preliminary washing as
         soon as the chipping and trimming are completed is desirable to remove
         loose materials. Washing by water jet is useful to remove loose particles.
         Final cleaning of the surfaces to which the new concrete is to be bonded
         should be done by wet sand blasting followed by washing with air water jet for
         thorough cleaning and drying with an air jet. Care should be taken to remove
         any loose materials embedded in the surface by chisels during the trimming
         and to eliminate all shiny spots indicating free surface moistures. Cleaning of
         steel if necessary should be accomplished by sand blasting. The prepared
         surface shall be approved by the Engineer-in-Charge.

96       DRY PACK OF CONCRETE
96.1     For this method of repairs, the holes should be sharp and square at the
         surface edges but the corners within the holes should be rounded, especially
         when water tightness is required. The interior surfaces of holes left by cone
         bolts, she bolts, etc., should be roughened to develop an effective bond.
         Other holes should be under cut slightly in several places around the
         perimeter. Holes for dry pack should have a minimum depth of 25mm.

97       CONCRETE REPLACEMENT
97.1     Preparation for this method should be as follows :
         (a) Holes should have minimum depth of 100 mm is new concrete and the
             minimum area of repair should be 500 sq. cm for reinforced and 1000 sq.
             cm for unreinforced concrete.
         (b) The reinforcement bars should not be left partially embedded there should
             be clearance of at least 25 mm around each exposed bar.
         (c) The top edge of the holes at the face of the structure should be cut to a
             fairly horizontal line. If the shape of the defect makes it advisable, the top
             of the cut may be stepped down and continued on a horizontal line. The
             top of the hole should be cut to 1 to 3 upward slope from the back towards
             the face of the wall or a beam. It may be necessary to fill the hole from
             both sides in which case the slope of the top of the cut should be modified
             accordingly.
         (d) The bottom and sides of the hole should be cut sharp and approximately
             square with the face of the wall, when the hole goes entirely through
             concrete section spalling or feather edges shall be avoided by having
             chippers worked from both faces. All interior corners should be rounded to
             a minimum radius of 25mm.

98       MORTAR REPLACEMENT – GUNITING
98.1     When mortar gun is used with this method, comparatively shallow holes
         should be flared outwardly at about 1:1 slope to avoid inclusion of rebound.
         Corners within the holes should be rounded. Shallow imperfections in new
         concrete may be repaired by mortar replacement if the work is done promptly
         after removal of the forms and while the concrete is still green for instance,
         when it is considered necessary to repair the peeled areas resulting from


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TECHNICAL SPECIFICATION

         surface materials sticking to steel forms and surface, may be filled using
         mortar guns without further trimming or cutting. Wherever hand placed mortar
         replacement is used, edges of chipped out areas should be squared with the
         surface leaving no feather edges.

99       USE OF DRY PACK MORTAR
99.1     The surface after preparing should be thoroughly brushed with a stiff mortar
         or grout barely wet enough to thoroughly wet the surface after which the dry
         pack material should be immediately packed into place before the bonding
         grout has dried. The mix of bonding grout is to be 1:1 cement and fine sand
         mixed to a consistency like thick cream. Under no circumstances should
         bonding coat be wet enough or applied heavily enough to make dry pack
         material more than very slightly rubbery. Dry pack is usually a mix (dry
         volume of weight) of one part of cement to 1 ½ parts of sand that will pass a
         1.18mm IS sieve. A mortar patch is usually darker than the surrounding
         concrete unless special precautions are taken to match the colours. Where
         uniform colour is important white cement may be used in sufficient amount to
         produce uniform appearance. For packing cone bolt holes a leaner mix of 1:3
         or 1:3 ½ will be sufficiently strong and will blend better with the colour of the
         wall. Only enough water should be used to produce a mortar which when
         used, will stick together on being moulded into a ball by slight pressure of
         hands and will not exclude water but will leave the hands damp. The proper
         amount of mixing water and proper consistency are those which will produce
         a filling which is at the point of rubbery when the material is solidly placed.
         Dry pack material should be placed and packed in layers having a compacted
         thickness of about 10mm. The surface of each layer should be scratched to
         facilitate bonding with next layer. One layer may follow another immediately
         unless appreciable rubberiness develops in which case work on the repair
         should be delayed to 30 to 40 minutes. Under no circumstances should
         alternate layers of wet and dry materials be used. Each layer should be
         solidly compacted over its entire surface by use of a hard wood stick and
         hammer. Much of the tamping should be directed at a slight angle and
         towards the sides of the hole to assure maximum compaction in these areas.
         The holes should not be overfilled and finishing may usually be completed at
         once by laying the flat side of a hardwood placed against the fill and striking it
         several good blows. If necessary, a few light strokes with a rag sometime
         later may improve the appearance. Steel finishing tools should not be used
         and water must not be used in replacement of concrete.

100 PROCEDURE OF REPLACEMENT OF CONCRETE,
    CURING OF REPAIRS ETC
100.1 All procedures for replacement of concrete, mortar replacement, use of
      epoxies and curing of repairs shall be according to the provisions laid down
      herein before.

101 COOLING OF CONCRETE
101.1 Heat release during hydration of cement when large masses of concrete are
      being produced, poses two different problems viz.
                  (i)     The thermal stability of concrete; and
                  (ii)    The cracking of concrete.




                                                                                       119
TECHNICAL SPECIFICATION

101.2 The thermal stability is necessary for normal behavior of the structure. So,
      suitable cooling system is to be adopted in the dam/structure concreting in
      order to rapidly achieve thermal stability.

101.3 In order to control thermal stability arising out of the heat of hydration, the
      placement temperature of concrete should be adopted as directed by the
      Engineer-in-Charge.

102 TOLERANCE FOR CONCRETE CONSTRUCTION
102.1 Permissible surface irregularities for the various classes of concrete surface
      finishes specified in the relevant portion of the section of “finishes and
      finishing of concrete surfaces” are defined finishes and are to be
      distinguished from “tolerances” as described in this section. Deviations from
      the established lines, grades and dimensions will be permitted to the extent
      set-forth in this clause, provided that lesser tolerances than those tolerances
      set-forth in this clause, may be prescribed at site if such tolerances are
      considered to impair the structural action or operational action or operational
      function of the structure.

102.2 Where tolerances are not stated in the specifications or drawings for any
      individual structure or feature thereof, permissible deviations will be
      interpreted in conformity with the provisions of this clause.

102.3 Concrete work that exceeds the tolerance limits specified in this section shall
      be either remedied satisfactorily or removed.

103 LOAD TEST WATER TIGHTNESS OF JOINTS OF
    AQUADUCT THROUGH SYPHON AND UNDER TUNNELS
    (WATER RETAINING STRUCTURES)
103.1       i)   Loading test is to be conducted after the completion of the
         construction of trough duly filled with water to 0.45m. above F.S.L. All the
         joints should also be tested for its effective water tightness. The test is to be
         conducted simultaneously with the load test of superstructure specified.

103.2       ii)  These tests are to be carried at the contractor’s expenses and the
         rate quoted by the contractor are expected to be including all these
         operations. However the withheld amounts by way of deposits will be
         released only after observance of the leakages for one year after release of
         water through the cross drainage works or after one year of the completion of
         the work in all respects and handing over it to the department.

103.3 iii)        Testing of water tightness :
           a) Contractor has to erect cross masonry bunds across canals at both the
              ends of structure upto the full height of side walls to required sections at
              his own cost for testing the water tightness of the trough slab and side
              walls of the structure.
           b) The contractor has to arrange for pumping of the water, once the
              structure is filled with water upto full supply level. It shall be observed
              for the period as desired by the Engineer-in-Charge, during which time
              any leakages are observed, it has to be rectified by the contractor at his
              cost to the full satisfaction of the Engineer-in-Charge.




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TECHNICAL SPECIFICATION

          c)   Once that the observation period satisfactorily over, he has to clear the
               debris, without damaging the concrete work of canal as directed by the
               Engineer-in-Charge.
                  The following tolerances shall apply for concrete in large concrete
                  structures:

(I)     (a)     Variation of the constructed linear In 6 metre           12 mm
                outlines from established position in
                                                      In 12 metres       20mm
                plan.

        (b)     Variations    of    dimension     to In 24 metres or 30 mm
                individual structural features from more
                                                                      Twice     the
                established position.
                                                     in        buried above amount.
                                                     construction.

(II)    (a)     Variations from the plumb, from the    In 3 metres       12mm
                specified batter or from the curved
                                                       In 12 metres      30mm
                surfaces of all structures including
                the lines and surfaces of walls and    or more
                vertical joints.                       In        buried Twice     the
                                                       construction     above amount.

        (b)     Variation from the level or from the In 3 metres         6 mm
                grades indicated on the drawings.
                                                     In 9 metres         12 mm
                                                       or more
                                                       In        buried Twice       the
                                                       construction     above
                                                                        amountl.

(III)   (a)     Variations in cross sectional Minus                      6 mm
                dimensions of columns, beams
                                                      Plus               12 mm
                butteresses, piers and similar
                members and variation in the
                thickness of slabs, walls and similar
                members of concrete of concrete
                upto M 25 strength.

        (b)     For concrete M 35 and above.           Minus             3 mm
                                                       Plus              6 mm

(IV)            Variation from plumb and level for Not         greater
                sills and side walls for radial gates than a rate of 3
                and similar water tight joints.       mm      in     3
                                                      metres.


104 PLACING REINFORCEMENT BAR
104.1 The following tolerances shall apply for placing of reinforcement bars.

(i)     Variation         of   protective Upto 50mm cover             3 mm
        covering
                                         Upto 75 mm. Cover & 13mm
                                         over


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TECHNICAL SPECIFICATION


(ii)   Variation    from    indicated Variation upto 12mm in spacing either way is
       spacing of reinforcement.      acceptable but total area of steel in the
                                      component is not reduced.



105 SAMPLING AND STRENGTH OF CONCRETE
105.1 The sampling shall be done as per the specifications laid down in IS 1199-
      1959-specification for sampling and analysis of concrete and testing of
      concrete shall be carried in accordance with IS : 516-1959 specification for
      testing strength of concrete.

105.2 For relatively small and unimportant buildings and structure in which quantity
      of concrete is less than 15 cum; the strength tests may be waived by the
      Engineer-in-charge.

105.3 The sampling scheme given in clause : 14 and the acceptance criteria given
      in clause 15 of IS 456-1978 are applicable to both design mix and nominal
      mix concrete. In the case of the later, the preliminary tests for establishing the
      mix proportions are not necessary.          Concrete of each grade shall be
      assessed, separately.

105.4 The concrete under acceptance shall be notionally divided into lots for the
      purpose of sampling, before commencement of work. The delimitation of lots
      shall be determined by the following :
                    i)    No individual lot shall be more than 30 cum. in volume.
                   ii)    At least one cube forming an item of the sample representing the
                          lot shall be taken from concrete of the same grade and mix
                          proportions cast any day.
                  iii)    Different grades of mixes of concrete shall be divided into
                          separate lots.
                  iv)     Concrete of a lot shall be used in the same identifiable
                          component of the structures.

106 SAMPLING AND TESTING
                   a) Concrete for making 3 test cubes shall be taken from a batch of
                      concrete at point of delivery into construction according to
                      procedure laid down in IS: 1199.
                   b) A random sampling procedure to ensure that each of the concrete
                      batches forming the lot under acceptance inspection has equal
                      chance of being chosen for taking cubes shall be adopted.
                   c) 150 mm. cubes shall be made, cured and tested at the age of 28
                      days for compressive strength in accordance with IS: 516. The
                      28day test strength result for each cube shall form an item of the
                      sample.
                    d) Three test specimens shall be made from each sample for testing
                       at 28days. Additional cubes may be required for various purposes
                       such as to determine the strength of concrete at 7 days or for any
                       other purpose.




                                                                                      122
TECHNICAL SPECIFICATION

                  e) The test strength of the sample shall be the average of the
                     strength of 3 cubes. The individual variation should not be more
                     than +15% or-15% of average.
                   f) Frequency : The minimum frequency of sampling of concrete of
                      each shall be

                Quantity of concrete in work, cum               No. of samples
                                  1–5                                       1
                                  6 – 15                                    2
                                 16 – 30                                    3
                                 31 – 50                                    4
                              51 – and above           4 + 1 additional sample for each
                                                       additional 50 cum or part thereof

                  At least one sample shall be taken from each shift of work.

107 TEST PROCEDURE
107.1 In order to get a relatively quicker idea of quality of concrete, optional tests
      one beams for modulus of rupture at 72+2 hours or at 7days, or compressive
      strength tests at 7days may be carried out in addition to 28 days compressive
      strength tests. For this purpose, the values given in Table may be taken for
      general guidance in the case of concrete made with ordinary portland cement.
      In all cases, the 28 days compressive strength specified in Table shall alone
      be the criterion for acceptance or rejection of the concrete. If, however, from
      tests carried out in a particular job over a reasonably long period, it has been
      established to the satisfaction of the Engineer-in-Charge that a suitable ratio
      between 28 days compressive strength and the modules of rupture at 72+2
      hours or 7 days or compressive strength at 7 days may be accepted, the
      Engineer-in-Charge may suitably relax           the frequency of 28         days
      compressive strength provided the expected strength values at the specified
      early age are consistently met.


                  OPTIONAL TESTS REQUIREMENTS OF CONCRETE

                   Grade of Compressive Strength on Modules of Rupture                        by
                   concrete 150 mm Cubes, Min. at 7 Beam test, Min.
                            days

                                                              At 72 +2h         at 7 days
                          1            2                          3               4

                                               N/mm2              N/mm2               N/mm2

                   M – 10                       7.0                   1.2              1.7

                   M – 15                      10.0                   1.5              2.1

                   M – 20                      13.5                   1.7              2.4




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TECHNICAL SPECIFICATION

108 7.20 STANDARD OF ACCEPTANCE
108.1 The standard of acceptance will be the same weather it is “Nominal Mix
      Concrete” or Design Mix Concrete. For relatively small and unimportant
      buildings and works in which quantity of concrete is less than 15 cubic metre,
      the strength tests may be waived by Engineer-in-Charge at his discretion.

108.2 Random samples from fresh concrete shall be taken as specified in IS:1199-
      1959 and cubes shall be made, cured and tested as described in IS:516-59. If
      required for some other purposes, for example, to estimate the time when the
      form work can be stripped, tests may be conducted at early ages also but the
      acceptance or otherwise is always on the basis of 28 days strength. The
      average of the strength of three specimens is the test strength of any sample.
      The total number of test results required to constitute an acceptable record for
      calculation of standard deviation shall be not less than 30. Attempts should be
      made to obtain the 30 test results, as early as possible, when a mix is used
      for the first time. The calculation of the standard deviation shall be brought up
      to date after every change of mix design and at least once a month. When
      significant changes are made in the production of concrete batches (for
      example changes in the materials used, mix design, equipment or technical
      control), the standard deviation value shall be separately calculated for such
      batches of concrete.

108.3 Where sufficient test results for a particular grade of concrete are not
      available, the value of standard deviation given in table 17 below may in
      assumed.




                                         TABLE - 17
                           ASSUMED STANDARD OF DEVIATION

                GRADE OF CONCRETE                      ASSUMED S.D. N/mm2

                          M-10                                    3.5
                          M-15                                    3.5
                          M-20                                    4.0
                          M-25                                    4.0
                          M-30                                    5.0
                          M-35                                    5.0
                          M-40                                    5.0



108.4 Concrete of each grade shall be assessed separately.

108.5 Concrete shall be assessed daily for compliance.



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TECHNICAL SPECIFICATION

108.6 Concrete is liable to be rejected if it is porous or honey combed; the
      reinforcement has been displaced beyond the tolerances specified; or
      construction tolerances have not been met. However, the hardened concrete
      may be accepted after carrying out suitable remedial measures to the
      satisfaction of the Engineer-in-Charge.

109 STANDARD DEVIATION
(i) Standard Deviation based on Test results :
                (a) Number of test results : The total number of test results required to
                    constitute as acceptable record for calculation of standard deviation
                    shall be not less than 30.Attempts should be made to obtain in the
                    30 test results, as early as possible, when a mix is used for the first
                    time check additional condition of about 5 samples.
                (b) Standard deviation to be brought up to date. The calculations of the
                    standard deviation shall be brought up to date after every changes
                    of mix design and at least once a month.
(ii) Determination of Standard Deviation
               (a) The standard deviation of concrete of a given grade shall be
                   calculated using the following formula from the results of individuals
                   tests of concrete of that grade.
               (b) Estimated standard deviations =




                                    
                                             Σ (Δ) 2
                               S=              -----------
                                               (n-I)
                          Where
                          Δ = deviation of the individual test strength from the average
                          n = number of sample test results
                (c) When significant changes are made in the production of concrete
                    batches (for example changes in the materials used, mix design,
                    equipment or technical control), the standard deviation value shall
                    be separately calculated for such batches of concrete.



110 ASSUMED STANDARD DEVIATION :
110.1 Where sufficient test results for a particular grade of concrete are not
      available, the value of standard deviation shall be as per the relevant IS
      codes.

111 ACCEPTANCE CRITERIA
111.1 The concrete shall be deemed to comply with the strength requirements if
             a) every sample has a test strength not less than the characteristic value,
                or
             b) The strength of one or more samples less than the characteristic value
                is in each case not less than greater of


                                                                                           125
TECHNICAL SPECIFICATION

             (i)     The characteristic strength minus 1.35 times the standard deviation
                     and

             (ii)    0.80 times the characteristic strength , and the average strength of
                     all the samples is not less than the characteristic plus
                    (1.65 – 1.65/Sqrt. ( number of samples ) times the standard
                    deviations.

111.2 The concrete shall be deemed not to comply with the strength requirements
      if:
         a) the strength of any sample is less than the greater of :
              1)      the characteristic strength minus 1.35 times the standard deviation;
                      and
              2)      O.80 times the characteristic strength :or
        the average strength of all the samples is less than characteristic strength
       Plus                   1.65 -          3               times standard deviation
                                        No.of samples
111.3 Concrete which does not meet the strength requirement as specified but
      111.1 above has a strength greater than that required 111.2 may, at the
      discretion of the designer, be accepted as being structurally adequate without
      further testing.

111.4 If the concrete is deemed not to comply the structural adequacy of the parts
      affected shall be investigated and any consequential action as needed shall
      be taken.

111.5 Concrete of each grade shall be assessed separately.

111.6 Concrete shall be assessed daily for compliance.

111.7 Concrete is liable to be rejected if it is porous or honey combed; its placing
      has been interrupted without providing a proper construction joint (or)
      tolerances have not been met. However, the hardened concrete may be
      accepted after carrying out suitable remedial measures to the satisfaction of
      the Engineer-in-charge

112 CORE AND LOAD TESTS
112.1 Inspection : Immediately after stripping the form work, all concrete shall be
      carefully inspected and any defective work or small defects either removed or
      made good before concrete has thoroughly hardened.

112.2 Incase of doubt regarding the grade of concrete used, either due to poor
      workmanship or based on results of cube strength tests, compressive
      strength tests of concrete core samples and or load test may be carried out.
               a) Core Test The points from which cores are to be taken and the
                  number of cores required shall be at the discretion of the Engineer-
                  in-charge shall be representative of the whole of concrete
                  concerned. In no case, however shall fewer than three cores be
                  tested.
                    Cores shall be prepared and tested as described in IS:516-1959.



                                                                                      126
TECHNICAL SPECIFICATION

                  Concrete in the member represented by a core test shall be
                  considered acceptable if the average equivalent cube strength of the
                  cores is equal at least 85 percent of the cubes strength of the grade of
                  concrete specified for the corresponding age and no individual core
                  has a strength less than 75 percent.
                  In case the core test results do not satisfy the requirements of or
                  where such tests have not been done, load test may be resorted to.
               b) Load tests on parts of structures : Loading tests should be
                  carried out as soon as possible after expiry of 28 days from the time
                  of placing of concrete.
                  The structure should be subjected to a load equal to full dead load of
                  the structure plus 1.25 times the imposed load for a period of 24 hours
                  and then the imposed load shall be removed.
                  NOTE : Dead load includes self weight of the structure members plus
                  weight of finishes and walls or partitions, if any, as considered in the
                  design.
                  The deflection due to imposed load only shall be recorded. If within 24
                  hours of removal of the imposed load, the structure does not recover
                  at least 75 percent of the deflection under superimposed load, the test
                  may be repeated after a lapse of 72 hours. If the recovery less than 80
                  percent, the structures shall be deemed to be un acceptance.

113 ACCEPTANCE CRITERIA
         Two sets of criteria for demonstrating that the concrete as produced and
         casted either complies or does not comply with the IS : 456-1978
         requirements for concrete quality.
         a) requirements of strength, and
         b) requirement of workmanship
         Compressive strength : When both the following conditions are met, the
         concrete complies with the specified compressive strength:
             a) The mean strength determined from any group of four consecutive
                samples should exceed the specified characteristic compressive
                strength.
             b) Strength of any sample is not less than the specified characteristic
                compressive strength minus 3MPs.

114 REJECTION CRITERIA
114.1    Concrete is liable to be rejected if it is.
   a) Porous or honeycombed,(due to incorrect mix proportions or improper
       compaction techniques)
   b) Its placing has been interrupted without providing a proper construction joint.
   c) The reinforcement has been displaced beyond the tolerance limit.
   d) If the core tests/load test does not yield the results.
   e) If the strength of the concrete produced and casted does not yield the strength
        requirements of the code.
   f) If the test results of the test cubes obtained as per IS : 1199 and tested as per
        IS : 516 does not yield the strength requirements of the code acceptance


                                                                                      127
TECHNICAL SPECIFICATION

        criteria, the Engineer-in-charge with the consultation of the Designer will
        consider the technical consequences such as durability, strength,
        serviceability, economic consequences, cost replacement, cost of
        strengthening the weak point etc.,
        However, the hardened concrete shall be accepted only after carrying out
        suitable remedial measures to the satisfaction of the Engineer-in-charge.

115 . UNACCEPTABLE WORK :
115.1 All defective concreting work including but not limited to defects arising out of
      honey combing, under sizing, under strength etc., are liable to be demolished
      and rebuilt by the contractor at his cost. In the event of such work being
      accepted by carrying out repairs etc., as specified by the Engineer-in-charge.
      the cost of repairs shall be borne by the contractor. Acceptance of such works
      will be in accordance with the provisions of IS : 456-1978.

115.2 Visible defects noticed in the workmanship and quality which could be
      rectified through remedial measures, shall be rectified to the satisfaction of
      the Engineer-in-charge.

115.3 Deficiency in workmanship which is considered to be attributable to some
      inadequacy in concrete production or concrete haulage, or concrete
      placement method, or compaction, should be got remedied from the
      contractor by the Engineer-in-charge       through additional inputs and
      upgradation of methodology and work taken up subsequently only when the
      needed augmentation has been done. If the subsequent work is within
      acceptable level, steps should be taken to remedy the defects noted in the
      earlier work through appropriate measure. After the defects have been
      remedied to the satisfaction of Engineer-in-charge and provided that the
      inputs (Cement, aggregates, water etc.,) are within the specified quality
      standards, the concerned work shall be accepted.

115.4 In case the Engineer-in-charge observes basic and serious deficiencies in the
      quality of inputs and outputs as well as in the workmanship, revealed through
      perusal of test records and visual inspection as well including say,
      examination of cores (taken from insitu concrete lining) as also serious in
      adequacies in construction equipment and job facilities in enforcing the
      technical specifications, such portions of works shall be rejected and not
      accepted for any payment. In the absence of any positive measures to
      strengthen these structures/works, the Engineer-in-charge may arrange for
      their demolition and reconstruction.

115.5 There could be portions of works/works, where some sort of slight
      transgression of specifications/ quality levels has taken place and which is not
      feasible of rectification in full. In case it is determined that the integrity of such
      portions of work is not significantly impaired and that the functional capability
      can be assured, consideration may be given by the Engineer-in-charge
      (subject to full satisfaction of the Engineer-in-charge) to accept these at
      reduced payment to the contractor instead of demolishing the concerned
      portion of work and reconstructing it.

116 CONCRETING UNDER HOT WEATHER CONDITIONS:
       When depositing concrete in very hot water, precautions shall be taken so that
       the temperature of wet concrete does not exceed 40 degrees Celsius while
       placing. This shall be achieved by stacking aggregate under the shade and


                                                                                       128
TECHNICAL SPECIFICATION

       keeping them moist, using cold water, reducing the time between mixing and
       placing to the minimum, cooling form work by sprinkling water, starting curing
       before concrete dries out and restricting concreting as for as possible to early
       morning and late evenings. When ice is used to cool mixing water, it will be
       considered a part of the water in design mix. Under no circumstances shall be
       mixing operation be considered complete until all ice in the mixing drum has
       melted.
       The contractor will be required to state his methodology for the approval of
       Engineer -in-charge when temperatures of concrete are likely to exceed 40
       degrees Celsius during the work.

117 INSPECTION AND TESTING OF STRUCTURES :
       Immediately after stripping the form work, all concrete shall be carefully
       inspected and any defective work or small defects either removed or made
       good before concrete has thoroughly hardened. In case of doubt regarding
       grades of concrete used, either due to poor workmanship or based on results
       of CUBE STRENGTH TESTS, Compressive strength tests on concrete
       structural elements shall be done as specified in clause :        16.3 - for
       core test and as specified in clause 16.5- for load tests on the part of the
       structures.

118 FINISHING :
       Immediately after removal of forms exposed bars or bolts, if any, shall be cut
       inside the concrete member to a depth at least 50 mm. below the surface of
       the concrete and the resulting holes filled with cement mortar. All fins caused
       by form joints, all cavities produced by the removal of form ties and all other
       holes and depression honey comb spots, broken edges or corners and other
       defects, shall be thoroughly cleaned, saturated with water, and carefully
       pointed and rendered true with mortar of cement and fine aggregate mixed in
       the proportion used in the grade of concrete that is being finished and of as dry
       a consistency as is possible to use. Considerable pressure shall be applied in
       filling and pointing to ensure thorough filling in all voids. Surfaces which have
       been pointed shall be kept moist for a period of 24 hours. Special pre-packed
       proprietary mortars shall be used where appropriate or where specified in the
       drawing.
       All construction and expansion of joints in the complete work shall be left
       carefully tooled and free from any mortar and concrete. Expansion joint filler
       shall be left exposed for its full length with clean and true edges.
       Immediately on removal of forms, the concrete work will be examined by the
       Engineer-in-charge before any defects are made good.
                          a) The work that has sagged or contains honeycombing to an
                             extent detrimental to structural safety or architectural
                             appearance will be rejected.
                          b) Surface defect of a minor nature shall be made good as
                             directed by the Engineer-in-charge.

119 CONCRETE SURFACE IRREGULARITIES :
 a)    General : Bulges, depressions and offsets are defined as concrete surface
       irregularities Concrete surface irregularities are classified as ‘abrupt’ or
       ‘gradual’ and are measured relative to the actual concrete surface.




                                                                                    129
TECHNICAL SPECIFICATION

  b) Abrupt surface irregularities: Abrupt surface irregularities are defined here-
     in as offsets such as those caused by misplaced or loose forms, loose knots in
     form timber, or other similar forming faults. Abrupt surface irregularities are
     measured using a short straight edge, at least 150 cm. long, held firmly against
     by direct measurement.
  c) Gradual surface irregularities are defined herein as, bulges and depressions
     resulting in gradual changes on the concrete surface. Gradual surface
     irregularities are measured using a template conforming to the design profile of
     the concrete surface being examined. Templates for measuring gradual
     surface irregularities shall be provided by the                     contractor.
     Templates shall be at least 2.5 m. in length. The magnitude of gradual surface
     irregularities is defined herein as a measure of the rate of change in slope of
     the concrete surface.
  d) The magnitude of gradual surface irregularities on concrete surface shall be
     checked by the contractor to ensure that the surfaces are within specified
     tolerances. The Engineer will also make checks of hardened concrete surface
     as deemed necessary to ensure compliance with these specifications.
     Templates for these surface shall be furnished by the contractor free of charge
     and shall be available for use by the Engineer at all times.

120 FILLING FOUNDATIONS WITH EXCAVATED
    MATERIALS, SOIL, SAND OR MOORUM.
Preparation : The ground over which filling has to be done shall be cleared of all
grass, loose, stones, rubbish of all kind as well as tree roots, bushes, etc. if there is
water it shall be pumped or bailed out.
The excavated material if to be used for filling should be properly stacked as per the
direction of Engineer-in-Charge and shall be cleaned of all the rubbish, large stones,
etc. and clods broken down to a size of 50mm or less.
Materials to be brought from out side i.e. sand moorum or yellow soil shall also be
cleaned of all rubbish and shall be used only after the approval of the Engineer-in-
Charge.
Laying : The approved soil, sand or morum shall be laid in 15 to 20 cm thick layers.
Each layer shall be watered and compacted with heavy rammers before the upper
layer is laid, till the required level is reached so as to form a thoroughly compact
base.
For filling in plinth watering and compaction shall be done in such a way as not to
endanger the foundation columns, plinth wall etc. already built up.
Under no circumstances black cotton soil or similar greatly expansive and shrinkable
soil shall be used for filling foundation or under the plinth.




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TECHNICAL SPECIFICATION

                                       APPENDIX – I
       PHYSICAL AND CHEMICAL REQUIREMENTS OF INDIAN STANDARD
                SPECIFICATIONS FOR DIFFERENT CEMENTS

Characteristic       Ordinar    Rapid       Low heat    High       Portland    Portlan
                     y          Hardenin    Portland    strength   Pozzolan    d slag
                     Portland   g           cement      Portland   a cement    cement
                     cement,    Portland    (IS:12600   cement     (IS:1489-   (IS:455-
                     (IS:269-   cement      -1989)      (IS:8112   1976)       1976)
                     1976)      (IS:8041-               -1976)
                                1976)

1                    2          3           4           5          6           7

Physical
Requirement
s

Fineness :
Specific
                     2250       3250        3200        3500       3000        2250
surface
(cm2/g),
minimum

Setting time,
                 30             30          60          30         30          30
vicat    initial
setting    time
(minutes),
minimum

Final setting
              10                10          10          10         10          10
time (hours),
Maximum

Soundness :

Le-Chatelier
                     10a        10a         10a         10a        10a         10a
method,
expansion            5b         5b          5b          5b         5b          5b
(mm),
Maximum

Autoclave
                     0.8        0.8         0.8         0.8        0.8         0.8
expansion,       *
percent,
Maximum

Heat           of
hydration
(cal/g.),
Maximum

7 days               -          -           65          -          -           -




                                                                                     131
TECHNICAL SPECIFICATION


28 days             -          -           75           -          -            -




d        -        Where x is the declared percentage of pozzolana.

e        -        Air-entraining or other agents which have proved not to be harmful.

f        -        Lime saturation factor        =             Cao-0.7SO3

                                                       2.8 SiO2 + 1.2 Al2O3 + 0.65

Fe2O3

X        -        Declared percentage of pozzolana in the given Portland pozzolana

cement.

                  The test is to be performed if MgO>3 percent.




                                                                                    132
TECHNICAL SPECIFICATION

                            APPENDIX – II
     DETERMINATION OF NECESSARY ADJUSTMENT FOR BULKING OF FINE
                     AGGREGATE (FIELD METHOD)
1.       Object :
         This method of test covers the field method for determining the necessary
         adjustment for the bulking of fine aggregate.
2.       General :
         Sand brought on to a building site or other works may contain an amount of
         moisture which will cause it, when loosely filled into a container, to occupy a
         larger volume than it would occupy if dry. If the sand is measured by loose
         volume, it is necessary in such a case to increase the measured volume of
         the sand, in order that the amount of sand put into the concrete may be the
         amount intended for the nominal mix used (based on dry sand), it will be
         necessary to increase the volume of sand by the “percentage” bulking. The
         correction to be made in only a rough approximation, because the system of
         measurement by order volume is a rough method at the best, but a correction
         of the right order can easily be determined and should be applied in order to
         keep the concrete uniform.
3.       Procedure :
3.1      The procedure to be adopted may be varied, but two methods, are suggested
         in 3.2 & 3.3. Both depend on the fact that the volume of inundated sand is the
         same as if the sand were dry.
3.2      Put sufficient quantity of the sand loosely into a container until it is about two
         thirds full. Level off the top of the sand and pushing a steel rule vertically
         down through the sand at the middle to the bottom, measure the height.
         Suppose this is h cm.
3.2.1    Empty the sand out of the container into another container where none of it
         will be lost. Half fill the first container with water. Put back about half the sand
         and rod it with a steel rod, about 6mm in diameter, so that its volume is
         reduced to a minimum. Then add the remainder of the sand and rod it in the
         same way. Smooth and level the top surface of the inundated sand and
         measure its depth at the middle with the steel rule. Suppose this is h’ cm.
3.2.2    The percentage of bulking of the sand due to moisture shall be calculated
         from the formula.
                               Percentage bulking = [ h/h’ – 1] x 100
3.3      In a 250ml measuring cylinder, pour the damp sand (consolidated by shaking)
         until it reaches the 200-ml mark. Then fill the cylinder with water and stir the
         sand well. (The water shall be sufficient to submerge the sand completely). It
         will be seen that the sand surface is now below its original level. Suppose the
         surface is at the mark y ml. The percentage of bulking of the sand due to
         moisture shall be calculated from the formula.
                              Percentage bulking = [200/y - 1] x 100
4.       Reporting of Results : Report the percentage bulking of the sand to the
         nearest whole number.
                                      APPENDIX – III
                              PHYSICAL REQUIREMENTS

 S.No               Requirement             Accelerating     Retarding        Water           Air
                                             Admixture       Admixture       reducing      Entraining


                                                                                        133
TECHNICAL SPECIFICATION

                                                          admixture    admixture

   (i)    Water content, percent of         -       -        95               -
          control sample, Max
  (ii)    Time of setting, allowable
          deviation   from    control
          sample, hours:
          Initial –
          Max                              -3      +3        +1               -
          Min                              -1      +1         -               -
          Final
          Max                              -2      +3        +1               -
          Min                              -1       -         -               -
  (iii)   Compressive       strength,
          percent of control sample,
          Min:
          3 days                          125      90       110              90
          7 days                          100      90       110              90
          28 days                         100      90       110              90
          6 months                         90      90       100              90
          1 year                           90      90       100              90
  (iv)    Flexural strength, percent of
          control sample, min :
          3 days                          110      90       100              90
          7 days                          100      90       100              90
          28 days                          90      90       100              90
  (v)     Length change,       percent
          increase    over      control
          sample, max:
          28 days                         0.010   0.010    0.010            0.010
          6 months                        0.010   0.010    0.010            0.010
          1 year                          0.010   0.010    0.010            0.010
  (vi)    Bleeding, percent increase       5       5         5               2
          over control sample, Max:




                                                                      134
TECHNICAL SPECIFICATION

                                           APPENDIX – IV
       REQUIREMENT FOR CONCRETE EXPOSED TO SULPHATE ATTACK

   Class         Concentration of Sulphates                Type of cement      Requirement for dense,
                    expressed as SO3                                              fully compacted
                                                                                concrete made with
                                                                               aggregates complying
                                                                                 with IS 383-1970
                          In Soil              In                                 Min         Max
                                            Ground                              cement     Free/water
                                             water                              content     cement
                                             (parts                                           ratio
                                              per
                                            100000
             Total SO3        SO3 in 2:1
             (Percent)          water
                               extract
                                g/litre
     1           2                3            4                 5                6            7
     1.      Less than        Less than               Ordinary      Portland   280 kg/m       0.55
                0.2              30                   cement or Portland
                                                      slag     cement     or
                                                      Portland     pozzolana
                                                      cement

     2.      0.2 to 0.5        30 to 120              Ordinary     Portland       330         0.50
                                                      cement or Portland
                                                      slag     cement    or
                                                      Portland    pozzolana
                                                      cement.

                                                      Super        sulphated      310         0.50
                                                      cement

     3.      0.5 to 1.0       120 to 250              Super sulphate cement       330         0.50
             1.9 to 3.1


Note 1 :          This table applies only to concrete made with 20mm aggregates
                  complying with the requirements of IS:383-1970 *placed in near
                  neutral ground waters of pH 6 to pH 9, containing naturally occurring
                  sulphates but not contaminants such as ammonium salts. For 40mm
                  aggregate the value may be reduced by about 15 percent and for
                  12.5mm aggregate the value may be increased by about 15 percent.
                  Concrete prepared from ordinary Portland cement would not be
                  recommended in acidic conditions (pH 6 or less). Super sulphated
                  cement gives an acceptable life provided that the concrete is dense
                  and prepared with a water/cement ratio of 0.4 or less, in mineral acids,
                  down to pH 3.5.
Note 2:           The cement contents given in class 2 are the minimum recommended.
                  For SO3 contents near the upper limit of class 2, cement contents
                  above these minimum are advised.




                                                                                        135
TECHNICAL SPECIFICATION

Note 3:           Where the total SO3 in col. 2 exceeds 0.5 percent, then a 2:1 water
                  extract may result in a lower site classification if much of the sulphate
                  is present as low solubility calcium sulphate.
Note 4:           For severe conditions such as thin sections under hydrostatic
                  pressure on one side only and sections partly immersed,
                  considerations should be given to a further reduction of water/cement
                  ratio, and if necessary an increase in the cement content to ensure the
                  degree of workability needed for full compaction and thus minimum
                  permeability.
Note 5:           Portland slag cement conforming to IS:455-1976 with slag content
                  more than 50 percent exhibits better sulphate resisting properties.
Note 6:           Ordinary Portland cement with the additional requirement that C3A
                  content be not more than 5 percent and 2 C3A + C4AF (or its solid
                  solution 4 CaO, AL2O3, Fe2O3 + 2CaO, Fe2O3) be not more than 20
                  percent may be used in place of supersulphated cement.




                                                                                       136
TECHNICAL SPECIFICATION

                                    APPENDIX – V
                          REQUIREMENTS FOR DURABILITY
MINIMUM CEMENT CONTENT REQUIRED IN CEMENT CONCRETE TO ENSURE
      DURABILITY UNDER SPECIFIED CONDITIONS OF EXPOSURE

             Exposure                   Plain concrete       Reinforcement concrete

                                       Mini        Max          Min      Max water
                                     cement        water      cement      cement
                                     content      cement      content      ratio
                                      Kg/m2        ratio       Kg/m3

                  1                     2            3           4            5
Mild – For example, completely         220          0.7         250         0.65
protected against weather, or
aggressive conditions, except
for a brief period of exposure to
normal weather conditions
during construction
Moderate – For example,                250          0.6         290         0.55
exposed sheltered from heavy
and wind driven rain and
against     freezing,     whilst
saturated with water; buried
concrete in soil and concrete
continuously under water.
Severe     –    For   example,         310          0.5         360         0.45
exposed to sea water, alternate
wetting and drying and to
freezing whilst wet, subject to
heavy       condensation     or
corrosive fumes.


Note 1:           When the maximum water cement ratio can be strictly controlled the
                  cement content in the above table may be reduced by 10 percent.
Note 2:           The minimum cement content is based on 20mm aggregate. For
                  40mm aggregate, it should be reduced by about 10 percent; for
                  12.5mm aggregate, it should be increased by about 10 percent.




                                                                                  137
TECHNICAL SPECIFICATION

                                     APPENDIX – VI
                          HOW TO BATCH CONCRETE BY VOLUME
1.       General
         The proper & accurate measurement of all the materials used in concrete
         making is necessary to ensure uniformity of proportions & aggregate grading
         in succeeding batches. When concrete is batched by volume there is always
         a danger of variation between one batch and another. So if on any job
         batching is specified by volume, a certain amount of extra care is required to
         make sure that quantities are correct.
2.       Gauging Cement
         Cement is often gauged by volume but this is most inadvisable except for
         small or unimportant jobs. The point against measuring cement by vol. (even
         when other materials are measured by vol.) is that it is difficult to secure
         accuracy in as much as actual volume of a given weight of cement depends
         upon how it is filled into the gauge box and whether it is shaken down. The
         density of cement may vary from about 1.12 g per cm 3 if it is lightly poured
         into the container to well over 1.60 gm per cm3 if tamped down sufficiently
         hard. Invariably, therefore, the size of the concrete batch should be so
         determined as to require whole bags of cement, but should a fraction of a bag
         be required it should be weighed into a bucket suspended from an ordinary
         50-kg spring balance.
3.       Gauging Aggregates by volume
         Aggregates can be gauged by vol. and for this purpose wooden batch boxes
         called farmas are used.
         The size of the farmas should be such as to measure the correct quantity of
         aggregates to be used with a whole bag of cement for the required mix. They
         should not be made so large as to be unwieldy; it is preferable to have a
         farma that will contain, say, half the required quantity of material, and to fill
         this twice over for each batch of concrete. Convenient sizes are indicated in
         Table given below:
         The farma should be made of 3 cm thick prepared timber, which gives a good
         strong job. Joints should be tongued & grooved with the tongue on the inside
         of the box. This prevents any dirt getting in if the joints should open through
         shrinkage or rough handling. The faces of the joints should all be painted with
         red lead linseed oil before the farma is assembled.
                                      SIZES OF FARMAS

          Capacity litres                          Inside measure

                                 Length, cm          Breadth, cm          Height, cm
                  25                  25                  25                   40
                  30                  25                  25                   48
                  35                  27                  27                   48
                  40                  29                  29                   48
                  45                  30                  30                   50
                  50                  31                  31                   52
         It is advisable to flash the top edge of the box with sheet metal to keep a
         clean level edge for striking off. The handles should be shaped to provide an
         easy grip.

                                                                                      138
TECHNICAL SPECIFICATION

         When a mixer machine is used on the job it will be convenient to have lips on
         the sides of the farma which can then be rested on the mixer hopper when
         the contents are being tipped in.
         Before concreting operations are started, the farma volumes should be
         checked for specified quantities. When filling the farmas the material should
         be thrown loosely into the box & struck off level; no compacting should be
         allowed. At the end of each day’s work the farma should be stacked upside
         down to prevent any accumulation of rain water.
4.       Calculating Batch Volumes
         A concrete mix is generally specified in parts by volume, as for example 1:1 ½
         :3, 1:2:4, etc. meaning one part of cement to so many parts of sand to so
         many parts of coarse aggregate. Since it is proposed to use only whole bags
         of cement these proportions must be converted to suit this unit.
         Take a mix specified as 1:2 ½ : 4. Now one 50 Kg. bag may be considered to
         hld 35 litres of cement, so above figures should be multiplied by 35. The mix
         will, therefore be : 50 Kg. of cement to 88 litres of sand to 140 litres of coarse
         aggregate.
         As these quantities of sand & aggregate are too large to be conveniently
         handled, the next thing, in this case, would be to have a farma for the sand
         made upto hold half of 88 litres (30x30x49cm) & fill it twice, & for the coarse
         aggregate a 35 litres farma, which would be filled four times. Farmas much
         larger than 50 litres in size are rather inconvenient to use.
5.       The Phenomena of Bulking
         The figures given above are for dry sand but, the sand as delivered and used
         on the job quite frequently contains moisture which causes films of water to
         form on the surface of the particles, fluffing them apart. This is called bulking
         and for a moisture content of about 5 or 6 percent may be as much as 20, 30
         or even 40% depending upon the grading of the sand, fine sands bulk much
         more than coarse sands. Further addition of water tends to flood or pack the
         sand decreasing the amount of bulking, and when the sand is completely
         inundated the volume is approximately the same as when measured dry &
         loose.
         If allowance for bulking is not considered when batching by vol. it will not only
         increase the cost of concrete by reducing the yield per bag of cement, but it
         will also have an under sanded mix which is harsh & difficult to place. An
         example given later will illustrate this point.
6.       Measurement of Water
         Of even greater importance than the accurate measurement of cement &
         aggregates is the proper control of mixing water. The strength & other
         desirable properties of a concrete mix depends entirely upon the quantity of
         water used to the bag of cement, the concrete becoming weaker as more
         water is added just as the cementing property of glue is impaired as it is
         mixed with more & more water.
         The prevailing method of gauging water “by the eye” with any odd tin can,
         direct into the mixer is most inaccurate & cannot be too strongly condemned.
         The mix design gives together with the specified mix, the exact quantity of
         mixing water to be used, as to many litres per 50 Kg. of cement. An exact 5
         litre measure is used to calibrated any other containers. This will ensure that
         the correct amount of mixing water is added to the concrete mix.

                                                                                       139
TECHNICAL SPECIFICATION

         For determining surface moisture, table 15 and for determining absorption by
         aggregate following table can be used.
                                              TABLE

         S.No.                    Aggregate                        Percent by weight

           (i)     Average sand                                          1 Percent
           (ii)    Gravel and crushed lime stone                         1 Percent
           (iii)   Trap rock and granite                                0.5 Percent
          (iv)     Porous sand stone                                    7.0 percent
           (v)     Very light and porous aggregate                     25.0 Percent
         The method of using these tables will be clear from the following example;
         Example :       Materials per batch 50 Kg of cement 88 litres of sand
                         (saturated, surface-dry) 175 litres of coarse aggregate.
         The engineer has pacified 25 litres of water to be used per 50 Kg. of cement.
         Correction for moisture : Suppose the sand used in moderately wet (surface
         water 65 gm per litre see table 15) and the coarse aggregate is also moist
         (surface water 30 g per litre)
         Then the total surface water carried by the aggregate is
         Sand = 65 x 88 = 5,720 g
         Coarse aggregate = 30 x 175 = 5,250 g
                                 10,970 gm say 11 litres
         Since this water is introduced into the mix with the aggregates, it must be
         deducted from the 25 litres specified by the Engineer, that is to say, only 14
         litres must be actually added to the batch at the time of mixing.
         If neglected to make this correction, the concrete mix would have contained
         36 litres per 50 Kg. of cement, causing a considerable reduction in its
         strength.
         Correction for absorption : If not infrequently occurs in our hot climate that the
         sand and coarse aggregate being used is bone-dry & will actually absorb
         water from the concrete, thus reducing the water cement ratio.
         Suppose the sand used weighs 1.60 gm per cm3 when dry (absorption 1.0
         percent by weight, see table on pre-page). The coarse aggregate is trap rock
         and weighs 1.44 g per cm3 (absorption 0.5 percent by weight.).
         Then the total water absorbed by the aggregate is
         Sand =          1 x 88 x 1.60 = 1.41 Kg.
                                  100
         Coarse aggregate = 0.5x175x1.44 = 1.26 Kg.
                                         ………………
                                         2,67 Kg.
                                 Say     2.7 litres
         This quantity must be added to the 25 litres specified by engineer, that is to
         say 27.7 litres must be added to the batch at the time of mixing.
         Loss or Water by Evaporation : In very hot dry weather it often happens
         that some of the water contained in the concrete mix is lost by evaporation
         during transporting & placing. An allowance may be made for this by a
         corresponding increase in the amount added at the mixer, prior approval of
         the engineer having been obtained.


                                                                                       140
TECHNICAL SPECIFICATION

        7. Summary

       The precautions that must be observed in the batching of concrete by volume
       can be summed up in a series of don’ts.
       (i)     Don’t gauge cement by vol. except for the most unimportant jobs.
               Determine the size of your batch so as to require whole bags of
               cement, but should a fraction of a bag be required weigh the cement
               into a bucket suspended from an ordinary 50 kg spring balance.
       (ii)    Don’t gauge aggregate into any old container. Have special farmas
               made on each job, carefully calculating their dimensions to suit the
               field mix proportions.
       (iii)   Don’t make farmas larger than about 50 litres otherwise they become
               unwieldy. It is preferably to use a farma which contains, say, half the
               required quantity & fill it twice over.
       (iv)    Don’t compact aggregates into the farma when filling them in. The
               aggregates should be loosely thrown into the box & struck off level.
       (v)     Don’t neglect to make allowance for bulking of sand, if any. Use the
               bulking test to determine the correct volume of damp sand that should
               be batchd which will be more than the volume of dry sand specified in
               the mix.
       (vi)    Don’t gauge water “by the eye” with any odd tin can direct into the
               mixer. Measure the water carefully into a calibrated container.
Don’t neglect to make allowance for the moisture that may already be present in the
aggregates when gauging mixing water.




”

                                                                  SECTION - 3
                                                   LINING OF CANAL
                                                                         INDEX
         1 General .............................................................................................................................................................. 178
         2 Standards .......................................................................................................................................................... 143
         3 CLEARING SITE: ............................................................................................................................................... 145
         4 PREPARATION OF SUBGRADE ...................................................................................................................... 146
         5 Cohesive Non-swelling Soils (CNS) for Treatment : ...................................................................................... 149
         6 Identification of CNS material .......................................................................................................................... 149
         7 Criteria for fixing the thickness of CNS Layer :.............................................................................................. 151
         8 Construction Procedure ................................................................................................................................... 151


                                                                                                                                                               141
TECHNICAL SPECIFICATION

        9 Pride : ................................................................................................................................................................ 153
        10 ........................................................................................... Use of Polyethylene Sheets Below Concrete Lining                                     153
        11 ........................................................................................... Under Drainage Arrangements and Joints in Lining                                     153
        12 ............................................................................................................................................... Laying of CNS soil :             154
        13 ......................................................................................................... Preparation of Subgrade consisting of soil                             154
        14 ........................................................................................................................................ Tolerance in Excavation                 154
        15 ........................................................................................................................... Under drainage of Lined Canals                       155
        16 ...................................................................................................................... Selection of drainage arrangement                         155
        17 .............................................................................................................................. Pressure Release Valve (PRV)                      156
        18 ................................................................. Use of Polyethylene Film under Rigid Surface Lining or Soil Cover                                              159
        19 ......................................................................................................................................................................... Film   159
        20 .....................................................................................................................................................................Grades      159
        21 ...................................................................................................................................... Preparation of Sub-grade                  160
        22 ...................................................................................................................................................Laying Technique              160
        23 ................................................................................................................... Cast in Situ Cement Concrete Lining                          200
        24 ................................................................................................................................... Laying of Concrete Lining :                  200
        25 ................................................................................. Tolerance in Concrete Thickness, Alignment and Grade :                                         201
        26 ......................................................................................................................................................................Mixing     201
        27 .................................................................................................................................................................... Placing     201
        28 ...................................................................................................................................... Hand Placing of concrete                  202
        29 ........................................................................................................................... Mechanical Placing of Concrete                       203
        30 ................................................................................................................................................................. Finishing      203
        31 ..................................................................................................................................................................... Curing     204
        32 ....................................................................................................................................................Surface Drainage             204
        33 ...................................................................................................................................................................... Joints    204
        34 ....................................................................................................................................................... Safety Ladders           206
        35 .............................................................................................................. PRECAST CEMENT CONCRETE LINING                                    206
        36 ........................................................................................................................MANUFACTURING P.C.C. SLABS:                              207


        37 .................................................................................................................................................................... Curing:     208
        38 .................................................................................................................... Testing of concrete and acceptance                          208
        39 .......................................................................................................................................... LAYING P.C.C. SLABS:                  209
        SPECIFICATION FOR CONCRETE LINING BY PAVER MACHINE ..................................................................... 212




                                                                                                                                                                   142
TECHNICAL SPECIFICATION


                             SECTION - 6 : LINING OF CANAL
1        GENERAL
1.1      Clearing site, preparation of sub grade in soils and rock, providing under
         drainage, pressure relief arrangements, anti salt treatment, placing model
         sections, laying plain cement concrete with machine crushed hard broken
         graded quartzite/ granite/ other than granite metal of 40 mm/ 20 mm.
         maximum nominal size and using cement level of not less than 250 Kgs. per
         cubic meter of concrete to yield a 28 days characteristic compressive strength
         specified based on laboratory tests for bed and sides respectively using
         conventional placement of concrete lining.

1.1      If during construction, it is found necessary to alter the canal sections and
         side slopes without altering the thickness of lining, the contractors shall be
         informed in writing of such changes.

1.2      cope of work also includes the following :
         (i)      Dewatering the canal section for preparing the base for lining and for
                  laying concrete lining.
         (ii)     Providing necessary, under drainage arrangements consisting of
                  longitudinal and  transverse drains, pressure relief valves as per
                  drawings.
         (iii)    Providing filter materials of approved quality as per designs.
         (iv)     Bed and side lining of the cement concrete with machine crushed hard
                  broken graded Quartzite/granite/ other than granite metal of 40 mm./
                  20 mm. nominal size and using cement of not less than 250 Kgs/cum.
                  of concrete to yield a characteristic compressive strength specified
                  based on laboratory tests respectively.
         (v)      Providing grooves for joints by cutting the concrete to the required
                  depth and width as per drawings.
         (vi)     Curing.
         (vii)    Filling joints.

2        STANDARDS
The following listing includes the Bureau of Indian Standards applicable for the
Excavation work
1.       IS : 456 -1978             Code of practice for plain and reinforced concrete
                                    (Second Revision) (Amendment No. 1).
2.       IS : 3873-1978             Code of practice for laying in-situ cement concrete
                                    lining first Revision of canals (First Revision)
3.       IS : 2505-1980             General requirements for concrete vibrators
                                    immersion type.
4.       IS: 2506- 1985             General requirements for screed board concrete
                                    vibrators.
5.       IS :3366-1965              Specification for pan vibrators.



                                                                                          143
TECHNICAL SPECIFICATION

6.       IS : 3558-1983     Code of practice for use of immersion vibrators for
                                  consolidating concrete.
7.       IS : 4558-1983      Code of practice for under drainage of lined canals.
         (First Revision)
8.       IS : 5256-1968      Code of practice for sealing joints in concrete lining
                              on canals
9.       IS : 3085-1965      Methods of test for permeability of cement mortar
                              and concrete.         .
10.      IS : 1199-1959      Method of sampling and analysis of concrete.
11.      IS : 516 -1959     Method of tests for strength of concrete (Amendment
                            No.1)
12.      IS : 5529-1985     Code of practice for in-situpermeability test.
                            (part I&II)
13.      IS: 9103-1979      Specifications for admixtures for concrete.
14.      IS : 2720-1980     Methods of test for soils Determination of water
                            (Part – 7)    content –dry density relation using light
                                    compaction (second revision)
15.      IS : 9451-1985     Guidelines for placing lining for Canals in expansive
                            soils. In addition to the above I.S. codes, the
      16. IS: 2508-1984     Specification for low-density polyethylene films.

      17. IS: 3873-1993     Code of Practice for laying cement concrete/stone slab
         lining             on canals.

      18. IS: 4558-1990     Revised draft for under drainage of lined canals,
         circulated by              BIS vide DOC; RVD 13(63) in Oct, 1993 for
         revision of IS:                    4558-1990.

      19. IS: 5256-1992     Code of Practice for sealing expansion joints in
         concrete lining                    on canals.

      20. IS: 5889-1970     Specification for vibratory plate compactor.

      21. IS: 7246-1974     Recommendation for use of           table vibrators       for
         consolidating              concrete.

      22. IS: 9451-1994     Guidelines for lining of canals in expansive soils.

      23. IS: 9698-1990     Revised draft for lining of canals with low density
         polyethylene               film circulated by BIS vide DOC:RVD 13 (155)
         in Oct. 1993 for                   revision of IS: 9698-1991.

      24. IS: 10430-1991    Criteria for design of lined canals and guidelines for
         selection                  of type of lining.


                                                                                    144
TECHNICAL SPECIFICATION

      25. IS: 10646-1992          Specifications on canal linings-Cement concrete tiles.

      26. IS: 13143-1991          Specification for joints in concrete lining of canals,
         sealing                                 compound.

      27. CWC Report              Lining of canals in Expansive Soils.

      28. June 1987

         Memo No.         Lining of main canals and branch canals of M.P. Composite

         WB-MP-9 of       Irrigation Project.

         WAPCOS

         T.C. 17          Canals in expansive soils-Identification and Treatment.

         T.C. 1/84        Concrete lining.

         T.C. 20          Necessity and type of drainage/arrangements behind Lining.

      29. CSMRS Report            Report of CSMRS on “Guide line for use of CNS soils”
         issued vide No. 8120/R-1/86-CSM/356 dated 18-8-87.


3 CLEARING SITE:
3.1      rea proposed for lining the canal as a whole shall be cleared of all
         objectionable material. Any waste material contained from such site clearance
         shall be disposed off in a manner directed by the Engineer-in-charge. The
         cost of this operation shall be deemed to have been covered under the rates
         quoted for canal lining.

3.2      The provisions of this para shall apply to the preparation of all sub-grade up
         on which concrete lining is to be laid. The work of trimming canal section upto
         the under side of concrete lining and preparing sub-grade for concrete
         placement includes removal of proud section. Proud equivalent to thickness
         of lining on sides and in bed on the underside of lining should be left un-
         excavated and the removal of this proud should be done prior to laying of
         lining but in no case, should the time interval exceed 3 days in normal
         weather and two days in adverse weather conditions.

3.3      It shall be ensured that the subgrade is made thoroughly moist with fine water
         spray, through deployment of proper nozzles, to a depth of about 15 cms to
         prevent it from absorbing water from the freshly laid concrete.

3.4      Soil in all reaches should be tested for salt content before lining is started.
         Where the salt content is over one percent or sodium sulphate is over 0.36
         percent, the sub grade should first be covered with about 2 mm. thick layer of
         bitumen, if ordered by the Engineer-in-charge It shall be treated in
         accordance with para 4.3 I.S. of 3873-1978.

3.5      Preparation of sub grade for concrete lining shall conform to clause 4.1 to
         4.5 of IS:3873-1978.




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TECHNICAL SPECIFICATION

3.6       Wherever rock is over excavated it shall be filled as specified under
          subsequent paras.

3.7       At the end panels of existing lining against which lining is to be placed under
          these specifications, all these materials shall be removed and all voids
          beneath the existing lining shall be refilled and thoroughly compacted.

4 PREPARATION OF SUBGRADE
4.1       ration of subgrade (Back filling) to canal side and bed lining with CNS soils of
          approved quality, obtained from available canal spoil including cost and
          conveyance of soils, Clearing the site, dewatering if necessary, treatment of
          the soil laying moistening compacting to 98% proctor’s density with suitable
          compacting equipment, trimming, all water leads, material leads, lifts, delifts,
          and all the operations necessary to complete the finished item of work to
          specifications, as per drawings or as directed by the Engineer-in-charge.


4.2   reparation of sub grade consisting of earth.
      a)     The sub grade shall be prepared, dressed and rolled true to level and
             according to the required cross- section of the canal to form a firm
             compacted bed for the lining.
      b      The contractor shall place selected bedding material, test profile true to
             the cross section of the canal at times and places designated by the
             Engineer to show the adequacy of his construction procedures for laying
             bedding materials. The test sections shall conform to clause 4.5.2.of I.S.
             3873. - 1978.
      c)     In other than predominantly sandy reaches where the dry density of the
             natural soil is not less than 1.8 gm. per cubic centimeter, initial excavation
             shall be done up to about 300mm. above the final section and the cutting
             to final shape shall be done immediately before lining. The compaction
             shall conform to Clause 4.5.6. of IS 3873-1978.
      d      If at any point material of prepared sub grade has been excavated beyond
             the neat lines required to receive lining, the excess excavation shall be
             filled in horizontal layers with suitable semi pervious soil material
             compatible with the sub grade material moistened and thoroughly
             compacted in accordance with Clause 4.5.5. and 4.5.6of I.S. 3873-1978.
             Where placing and compacting bedding materials is on slopping
             foundation, the layers may be placed parallel to the surface of the
             foundation. If at any point, the foundation. material is disturbed or
             loosened during the excavation process or other wise, it shall be
             moistened if required, and thoroughly compacted by tamping, rolling or
             other approved methods to form firm foundation for placing the concrete
             lining. Slope compactors may also be used for effective compaction of
             subgrade.
      e)     In bed, where the dry density of the natural soil is less than 1.8 gm. per
             cubic centimeter and sub soil water is near the sub grade, the
             consolidation shall be done by under cutting the bed by 7.5cm and then
             ploughing upto 15.0cm. below the subgrade level. The loosened soil shall
             then be recompacted with suitable devices. All along the canal alignment
             the raincuts on the banks shall be filled up with approved soil and shall be
             compacted adequately to required lines, dimensions and levels.



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TECHNICAL SPECIFICATION

       f)    In bed where the sub soil water is low, requiring no dewatering and the
             dry density of the natural soil is less than 1.8 gm. per cubic centimeter, the
             consolidation shall be done by digging the canal up to sub grade level and
             after loosening the earth below subgrade up to 15.0cm. by disc harrows,
             or ploughing and compacting the same to a layer of 11.0cm. After that, the
             second layer of 15.cm. of earth shall be laid over the compacted layer by
             taking earth from lip cutting and compacting this to a depth of 11.00cm.
             The compacted layer of 7.0 cm above the subgrade level. shall be
             removed and the subgrade brought to design profile before laying the
             lining.
      g)     Consolidation on sides shall be done by suitable slope compactors to
             obtain a minimum dry density of not less than 90-98% of the density at
             optimum moisture content obtained in accordance with IS : 2720(part vii)
             1965. Compaction by manual labour shall not be permitted.

4.3      Preparation of subgrade consisting or rock.
  a) The sub grade in rock shall be excavated to the required cross section. Final
     cutting for 450-600 mm. in hard rock shall be carried out by, wedging, barring
     controlled blasting or trimming with the help of suitable equipment. No extra
     payment will be made to this.
  b) The bed and side slopes of the canal excavation profile over which the bedding
     material, under drainage and pressure relief arrangements are to be placed
     and over laid with lining shall be finished accurately to true and even surfaces
     and to the dimensions shown on the drawings.
  c) All excavation including over breakages below the lines of the underside of
     lining shall be back filled as follows:
       In slopes : In slopes, the selected bedding material shall be semi pervious
       material forming, the bulk of back fill with smaller aggregate filling the voids,
       and a layer of gravel as binding material duly compacted with rammers to form
       a firm backing for the lining (IS: 3873-1978).
       In bed : In case of bed, the selected bedding material shall be rock spells and
       chips available from canal cutting duly compacted with Diesel Road Roller to
       form a firm backing to lining (IS: 3873-1978).
       Tolerance in Excavation :- Excavated profile provides the final base for lining
      and tolerances should be comparable to the following :
       Departure from established alignment :
       (+) or (-) 2 mm. on straight section:
       (+) or (-) 50 mm. of tangents, and
       (+) or (-) 100 mm. on curves.
       (+) or (-)20 mm. Departure from established alignment.
       The above tolerances shall be negotiated gradually, through smooth transition
       in a length of 50 m. No over- run in excavation. Filling with the materials as
       directed by the     Engineers-In-Charge shall be executed by the contractor
       without any additional cost.
       The selected bedding material in the cases of bed and sides of canal profile in
       normal soils shall be graded filter material comparable with sub grade material
       and thoroughly compacted.

4.4      Preparation of sub grade consisting of expansive soils. (IS : 9451-1995



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TECHNICAL SPECIFICATION

4.4.1    Expansive soils in side slopes and bed of canal in cutting or embankment
         when in contact with water swell, exerting a swelling pressure which may
         range from 50 to 300 kN/m2 or more. This characteristic of swelling and the
         swelling pressures of black cotton soil is attributed to the pressure of
         montmorinolite or combination of montmorinolite and illite clay minerals. A
         wide range of properties of expansive soils are found in India (See IS:1498:
         1992 for identification and properties)

4.4.2    The swelling pressure and free swell index tests should be done in
         accordance with IS: 2720 (Part 40) 1992 and IS: 2720 (Part 41) : 1992.
         Expansive soil met within the locality has to be analyzed for swelling pressure
         before deciding the type of treatment. For testing the expansive soil for
         determination of swelling pressure the expansive soil specimen should be
         remolded at zero moisture content to the density obtainable at any time in the
         year in the field at a depth beyond 1.0 m (in expansive soil). The swelling
         pressure should be determined under no volume change condition when
         moisture content is increased from zero to fill saturation level.

4.4.3    Identification of expansive soil: Following identifications are generally
         observed in the case of expansive soil:
               (a)    During summer wide deep and map type cracking is normally
                      observed in expansive soils
               (b)    Walking over such soil is rendered difficult during heavy rain.
               (c)    Thorny bushes, thorny trees (Babul) and cactus constitute the
                      normal vegetation in such soil in India.
               (d)    Buildings constructed using conventional methods exhibit heaving
                      of floors, cracking of walls and jamming of doors during rainy
                      season. Retaining structures get tilted and roads get rutted and
                      heaving and side slips and sloughing are noticed in canal.

4.4.4    The expansive soils can be identified by following visual properties
         Colour           -      Black, Grey, Yellow and Yellowish Grey.
         Land Slope       -      Normally 0 to 2.
         Drainage         -      Generally poor.

4.4.5    Physical Properties of Expansive soils: The grain size and index properties of
         such deposit expressed in percentage are in the following range

Grain Size                                      Percentage

                                         Gradation

Clay (Less than 2 micron)                       50 to 70

Silt (0.06 mm to 0.002 mm)                      20 to 35

Sand (2 mm to 0.06 mm)                          30 to 50

Gravel (greater than 2 mm)                      Less than 10%

                                      Index Properties

Liquid limit                                    60 to 100


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TECHNICAL SPECIFICATION


Plastic limit                                30 to 50

Plasticity Index                             30 to 40

Shrinkage limit                              8 to 12




4.4.6    Field and laboratory experiments shall be carried out to determine the
         physical, texture, engineering and chemical properties of the black cotton
         soils/expansive soils and evaluate the swelling pressures of soils in various
         reaches to establish the thickness of CNS. layer required so that the
         determination is within the permissible limit.

4.4.7    In respect of the provision of CNS layer is worked out from the consideration
         of swelling pressure. However, the thickness of CNS layer to be provided on
         slopes shall, in addition, be governed by the construction considerations viz.,
         from rollable width consideration for achieving effective compaction. However
         making due allowance for field controls, variations in the properties of CNS
         materials in the field an optimum thickness of 600 mm. normal to the slope
         shall be used in the channels of discharge more than one cumec. The
         thickness shall be appropriately decreased to 300 mm. (150mm. in small
         section of less discharges) channels. Filling and compaction of CNS material
         in such channels shall be done by pad/file and cut method as specified in the
         drawings.

5 COHESIVE NON-SWELLING SOILS (CNS) FOR
  TREATMENT :
5.1 They are soils possessing the property of cohesion of varying degree and non-
    expanding type clay minerals such as illite and Kaolinite and their combination
    with low plasticity with liquid limit not exceeding 50 percent.

5.2 Some of the soils which may be considered as cohesive non swelling soils are all
    adequately compacted clayey soils, silty clays, sandy clays, gravelly sandy clays,
    etc. exhibiting cohesive properties and containing predominantly non-expanding
    type clay minerals.

5.3 CNS material should be non-swelling with a maximum swelling pressure of 10
    KN/m when tested in accordance with IS:2720 (Part 41) : 1992 at optimum
    moisture content and minimum cohesion (unconfined compression strength on
    saturated compacted soil, remoulded at OMC and compacted to standard proctor
    density) should be 10 KN m2 when tested according to IS:2720 (Part 10) : 1991.

5.4 If given CNS material is not available, designed mix to produce blended CNS
    may be used. The artificial CNS. If stabilized material is to be used, special mix
    design needs to be evolved.

6 IDENTIFICATION OF CNS MATERIAL
6.1 The CNS material can be identified by using –
         (a) Visual properties :


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TECHNICAL SPECIFICATION

             Colour     : Red, Reddish, Yellow, Brown, White, Whitish Grey, Whitish
             yellow, Green and Greenish gray.
             Land Slope        : Normal land slopes are between 2 and 10, though on
             flatter slopes they are many times encountered within 3m below the
             overlaying expansive soil.
             Drainage : Generally good
         (b) Identification using Activity chart –
             This chart (Fig. 1) classifies the soil into Active, Normal and Inactive soils
             based on Plasticity Index and clay fraction present in the soil.
             It is desirable to first check sample on this chart to see that the soil does
             not fall into Active zone. The soil sample identified on this chart as
             suitable, i.e. not falling into Active zone shall only be checked on A-line
             chart (Plasticity Chart) in accordance with the procedure laid down in para
             (c) below.
         (c) Use of line chart (Fig. 2) is made for general identification of the CNS
             material. In this method the data required is only liquid limit (LL) and
             Plasticity Index (PI). The CNS soil has to resist internal erosion due to
             seepage and form suitable base for lining the soil with LL less than 30%
             and PI less than 15% is not considered suitable. The Zone covered
             between LL 30 to 50% and PI 15 to 30% is shown hatched. Soils falling in
             this zone can be considered suitable to be used as CNS material.
             However, it is desirable to have a few representative samples tested for
             swelling pressure as a cross check.
             In case of samples falling in Zone “A” of the chart, it would be necessary
             to ascertain swelling pressure and cohesion of such sample before
             accepting the same as CNS material.
             CNS soil normally should not exhibit swelling pressure, but in exceptional
             cases swelling pressure less than 0.1 kg/cm2 is acceptable. Minimum
             cohesion should be 0.1 kg. cm2 (10 KN/m2).

6.2 Physical Properties of CNS Soils : Most murums of laterite, laterite type and
    siliceous sandy clay exhibit CNS characteristics, however some murums may be
    of swelling type. Unlike swelling soils, they do not exhibit cracking during
    summer, nor heaving and stickiness during rainy season. Structures constructed
    on such soil do not exhibit heave though they may sometimes settle. The CNS
    are generally red, reddish, yellow, brown, yellow, white, whitish gray, whitish
    yellow, green and greenish gray in colour. Although, several soils contining non-
    expanding type clay mineral exhibit CNS properties, the following range helps in
    locating such types :
                                                                 Percent (%)
                  Clay (less than 2 microns)           :         15 to 20
                  Silt (0.06 mm – 0.002mm)             :         30 to 40
                  Sand (2mm – 0.06 mm)                 :         30 to 40
                  Gravel (Greater than 2mm)     :      0 to 10
                  Liquid limit                         :         Greater than 30 but les
                  than 50
                  Plasticity Index                     :         Greater than 15 but less
                  than 30



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TECHNICAL SPECIFICATION

7 CRITERIA FOR FIXING THE THICKNESS OF CNS LAYER :


7.1 Thickness of CNS materials is related to swelling pressure and the resultant
    deformation. The permissible deformation is 2 cm.

7.2 Guidelines for choosing the thickness of CNS materials required for balancing the
    different swelling pressure is given in Table 1A and 1B. Slopes should be in
    accordance with IS : 10430:1982.
   Table 1 –A Thickness of CNS layer, Carrying Capacity less than 2 Cumecs.

  Discharge in cumecs          Thickness of CNS Swell      Layer in cm (Min) Swell
                               Pressure 50-150 KN/m2       Pressure more than 150
                                                                   KN/m2
            1.4 – 2                       60                           75
           0.7 – 1.4                      50                           60
           0.3 – 0.7                      40                           50
          0.03 – 0.3                      30                           40


Table 1 – B Thickness of CNS layer, Carrying Capacity of 2 Cumecs and more.
   Swelling Pressure of Soil KN/m2             Thickness of CNS Materials cm
                                                        (minimum)
                   50 to 150                                   75
                  150 to 300                                   85
                  300 to 500                                   100
Note : However, optimum thickness of CNS material needs to be determined for
different swelling pressures by actual experiments both in field and laboratory, if
required.

8 CONSTRUCTION PROCEDURE
8.1 To counteract the swelling pressure and prevent deformation of the rigid lining
    materials, a CNS material of required thickness depending on the swelling
    pressure of expansive soil, is sandwiched between the soil and the rigid lining
    material. The thickness of CNS layer should be measured perpendicular to the
    surface of expansive soil.

8.2 Canal in Cutting
Long deep cuts in expansive soils should be avoided and where possible a detour
should be considered.
In cutting special care will be necessary to compact the CNS materials against the
excavated surface of the cuts. The material should be spread uniformly in their
horizontal layers of specified thickness (15 cm thick). Care also is necessary in
obtaining a good joint between the two materials, by thoroughly wetting the
excavated surface, so as to avoid slips at the junction plane. The construction should
be carried out in the following steps:
         (a) While excavating provision should be made for accommodating required
             thickness of CNS layer on bed and sides. The sub-grade on which CNS

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TECHNICAL SPECIFICATION

             layer is to be laid should generally not be kept exposed for more than for
             days, prior to the placement of the CNS layer.
         (b) Serrations should be provided in expansive soil to prevent contact sides
             between CNS materials and expansive soil.
         (c) Proper moisture should be added to CNS material.
         (d) CNS materials should be compacted in layer by appropriate equipment to
             ensure proper density.
         (e) CNS on side slopes should be trimmed to the required thickness. The
             thickness is measured perpendicular to the surface of expansive soil.
         (f) Suitable canal lining over CNS material should be provided depending on
             the site and economic condition.
         (g) To avoid slipping and rain cuts during the rainy season, it is advisable to
             provide CNS right up to the ground level.
         (h) In deep cuts CNS material should be provided not only behind the lining
             of the canal but also above the canal prism, all along the excavated
             surface, so as to prevent large scale heaving above the canal level. The
             CNS material above the canal prism may be of lesser thickness say 15 to
             20cm. However, full design thickness behind the lining should be
             continued at least 100 cm above the top level of lining (illustratory
             arrangement shown in Fig. 3).
         (i) The stability of the slopes, particularly in the case of cuts, if very adversely
             affected by rain water finding its way into the tension cracks and exerting
             hydrostatic force on the slipping mass of the soil. Covering the surface of
             the slopes by CNS materials and proper surface drainage will reduce the
             chances of rain water finding its way into the cracks.
         (j) It is necessary to stack the excavated soil away from the cuts to prevent
             in inducing slips by surcharge.

8.3 Canal in Embankment
The construction should be carried out in the following steps :
         (a) Proper moisture should be added to CNS material and expansive soil.
         (b) Expansive soils CNS material above ground level should be composed
             simultaneously in layers with appropriate equipments to ensure proper
             density.
         (c) The CNS material in embankment should be laid and compacted in layers
             simultaneously with the body of the banks, so as to obtain good
             compaction and to avoid any slippage plane being developed between the
             two materials. The compaction of CNS materials should also be to the
             standard proctor density with optimum moisture content. It may be done
             either with sheep foot rollers or 8 to 10 ton ordinary rollers.
         (d) Provision of surface drain and internal drainage filter should be made to
             minimize external/internal erosion. A rock toe with inverted filter may be
             provided at either end of canal bank.
         (e) Special care is required to be taken to provide internal drainage for the
             banks, having bed filling of 2 meters or more. A sand blanket is spread on
             the base of the bank and rock fills with regular inverted filters are also
             necessary at the outer toes.




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TECHNICAL SPECIFICATION

         (f) For both the cuts and banks, paved surface drains should be provided at
             the berms, to avoid erosion of the finished surface. As far as possible,
             water from these drains should be drained away from the canal.
         (g) The drainage properties of the CNS material itself need to be given due
             consideration as water locked up in this saturated layer is likely to cause
             pore pressures on the lining during canal draw-down conditions.
         (h) Murum (gravelly soil) material on outer slopes of canal embankment
             should be trimmed to the required thickness.
         (i) To protect outer slopes from erosion, proper turfing should be used.

8.4 Similar procedure should be followed for canal in partial cutting and embankment.

9 PRIDE :
9.1 The problem of effectively compacting the sub-grade for side lining on slopes is
    very important in case of black cotton expansive soil zone in cutting or
    embankments, where backfill of CNS material is required to be placed for the
    sides and bed, in addition to design thickness. Twenty cm or so (perpendicular to
    side slope) of extra pride may be provided and compacted in horizontal layers to
    the required density. This pride should be removed only just prior to the
    placement of lining, thus making a fresh and well-compacted surface available for
    bedding.

9.2 For cutting in soft material where the CNS backfilling is not required the best
    method is to leave the cutting 20 cm or so undercut (Perpendicular to the canal
    slope) and remove this undercut only just prior to the placement of concrete
    lining. Similar procedure may be adopted in case of cutting in hard strata.

10 USE OF POLYETHYLENE SHEETS BELOW CONCRETE
   LINING
10.1 The use of polyethylene sheet below concrete lining could be either for
   achieving better ultimate imperviousness of the lining as a whole or it may be
   used only for limited purpose as an assistance, during construction, for avoiding
   the cement slurry from concrete escaping in the sub-grade below. Use of LDPE
   sheets 200 gauge (50 microns) is to achieve only the latter limited purpose. If
   overall imperviousness is proposed to be achieved, it would be necessary to use
   HDPE-HM sheet of sufficient thickness, strength, toughness and durability.

11 UNDER DRAINAGE ARRANGEMENTS AND JOINTS IN
   LINING
11.1 The drainage properties of CNS material itself need to be given due
   consideration as water locked up in this saturated layer is likely to cause pore
   pressure on the lining during canal draw down conditions. To release the same if
   holes are provided for drainage in concrete lining, care will have to be taken to
   provide inverted filters at the back of the holes so as to avoid the CNS material
   being washed away by fluctuating water levels in the canal. Such drainage holes
   are, however, not advocated for general adoption.

11.2 It is recommended to provide regular drainage arrangements using porous
   concrete sleeper, 7.7 cm x 20cm with 50mm perforated G.I. Pipes at 3 m centre
   to centre coming out through the sides of the lining. Two porous concrete
   sleepers on either side of the bed, below the side may be provided. A 50 to


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TECHNICAL SPECIFICATION

    75mm thick sand mat below the bed and side cast in situ lining (below the
    polyethylene sheet) should be provided. Where the sand mat is not economically
    feasible additional porous concrete sleepers may instead be provided at right
    angles to the longitudinal rails (along the cross section of the canal) at 3m centre
    to centre. The porous concrete sleepers have to be encased in filter materials.
    (Fig. 4).

12 LAYING OF CNS SOIL :
12.1 The CNS layers should be firmly bonded at the interface of CNS and
   expansive soil through provision of serration in expansive soil base and thorough
   compaction of interface layers.

12.2 Before placement of CNS material the surface of excavation of embankment
   to receive CNS shall be roughened & thoroughly wetted about 15cm so as to
   ensure firm bond between the original surface & CNS layer.

12.3 CNS soil should be compacted in suitable layers so as to obtain the density
   not less than 90% of M.D.D. at its optimum moisture content or slightly on the
   drier side of optimum but not lower than 1 percent.

13 PREPARATION OF SUBGRADE CONSISTING OF SOIL
13.1 The Subgrade should be prepared, dressed and rolled true to level and
   according to the required cross-section of the canal to form a firm compacted
   subgrade for the lining.

13.2 In other than predominantly sandy reaches where the dry bulk density of the
   natural soil is nor less than 1.8g/cm3, initial excavation should be done up to
   about 30 cm above the final section and the cutting to final shape should be done
   immediately before lining.

13.3 Over excavation in hard strata having side slopes flatter than 1:1 beyond the
   profile line may be backfilled with gravel and aggregate, large aggregate forming
   the build of backfill with smaller aggregate filling the voids and a layer of pea
   gravel as binding material. The bed may then be compacted with road roller and
   sides with hammers to form a firm backing for the lining.

13.4 For over excavation in hard strata having side slope steeper than 1:1 beyond
   the profile, the backfilling may be suitably done with chip masonry or lean
   concrete. However, for bed the backfilling may be done with properly compacted
   murum. Over excavation upto 5 cm may be back filled. If over excavation is up to
   10 cm, lean concrete may be used. Beyond 10cm backfilling with chip masonry is
   preferably.

13.5 For slip-form paving, over excavation up to 10 to 15 cm may be required.
   Such over excavation may be backfilled with selected material and compacted at
   optimum moisture. The material selected should be machine trimable and be
   gravel/stone-free earth.

13.6     Tar paper shall be used for placing concrete.

14 TOLERANCE IN EXCAVATION
14.1 Excavated profile provides the final base for the lining and the tolerance
   should be comparable to those required for paving.


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TECHNICAL SPECIFICATION

                  Departure from established alignment :
                  +       20 mm on straight section
                  +       50 mm on tangents, and
                  +       100 mm on curves
                  Departure from established grade : + 20 mm

15 UNDER DRAINAGE OF LINED CANALS
15.1 Where a lined canal crosses areas subject to seasonal high ground water or
   where the soil is sufficiently water tight to prevent the free draining of the
   seepage or leakage from the canal, suitable under drainage shall be provided to
   protect the lining. Where the sub-grade is free draining but the area is subject to
   high ground water, excessive hydrostatic          pressure sufficient to damage the
   lining may develop at its back when the canal is empty or the water level in the
   canal is relatively low and the ground water level is high. A similar situation may
   occur in areas where the canal is lined for reasons other than to prevent seepage
   and soil is sufficiently water tight to prevent free drainage of leakage from the
   canal, the accumulation of water in the soil surrounding the canal may result in
   local high ground water table which during a period of rapid draw down of water
   level in canal may produce damaging hydrostatic back pressure.

         METHOD OF UNDER DRAINAGE
15.2 The under drainage of canal lining for the following types of sub grades may
   be accomplished by the methods specified in Clause 16
       a) Free drainage sandy soil – Soil comprising of gravel and clear sand or
          clear
          sand. This may have a permeability greater than 10-4 and less then 10-3
    cm/sec.

         b) Poor draining – Soil comprising of very fine sand admixture of sand, silt
            and clay or clay. Soil with permeability less then 10-4 cm. sec and grater
            than 10-6 cm/sec;and

         c) Practically impervious – Soil comprising of homogeneous clays below
            zone of weathering. Soil with a permeability less then 10-6 cm/sec.


16 SELECTION OF DRAINAGE ARRANGEMENT
16.1 The drainage arrangements provided to reduce or eliminate hydrostatic
   pressure behind lining usually comprise of longitudinal drains, cross - drains,
   pressure release valves and continuous filters. These are provided singly or in
   combination depending upon classification of sub-grade and position of GWT.
   The type of drainage arrangement to be adopted depending upon discharge of
   canal classification of sub-grade and position of GWT is given in Annexure – I.
   Where extensive lining works are involved, the adequacy of various drainage
   arrangements could be determines on their dimensional Electrical Analogy Model
   at the discretion of Chief Engineer.

16.2 Various components of drainage arrangements are described in following
   paras.



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TECHNICAL SPECIFICATION

17 PRESSURE RELEASE VALVE (PRV)
17.1 Pressure Release Valve (PRV) is a valve provided in a canal lining, which
   opens into the canal to relieve excess hydrostatic pressure behind the lining. The
   PRV shall be such that it will operate a differential pressure less than which will
   be damaging to the lining with factor of safety of two. This should be operative
   generally with a differential head of 100 mm and above. PRV should generally be
   of such material which will be abrasive resistant and which will not be affected
   due to its presence in the water PRVs made of plastic, fibre glass, P.V.C. etc.
   which are strong but have no resale value should be used. This would discourage
   pilferage, which is common with metallic valves. 50mm, 75mm, 100mm and
   150mm diameter valves are generally used for release of pressure behind lining.
   Typical pressure release valve and PRV housed in pocket filter is shown in
   Figure - 5.
The size of PRVs for different conditions of water table/discharge of channel shall be
provided as indicated in table –2.
                                         Table - 2

S.       Water table           Discharge upto 15 cumecs     Discharge    above     15
No.                                                         cumecs

                               Bed            Slope         Bed          Slope

         …………………………Diameter of PRV in mm…………………………..

i.       GWT below CBL         50             50            100          50

ii.      GWT above CBL         75             50            150          50

17.2 Pocket filter: The pressure release valves are provided in pockets filled with
   graded filter or concrete/masonry outlets with graded metal underneath the lining.
   The dimensions of outlet/pocket filters with reference to dimensions of PRV shall
   be as indicated in table –3.
                                         Table - 3

 Category        Size of Pressure release Size of outlet/pocket filter
                 valve

                 Diameter      Length of Length              Width        Depth
                 mm            Strainer  mm                  mm           mm
                               pipe mm

Outlet           150           500 + T       450             450          600

                 100           500 + T       450             450          600

Pocket           75            500 + T       1050            1050         950
Filter
                 50            450 + T       600             600          600

Note: “T” represents thickness of lining in mm




                                                                                  156
TECHNICAL SPECIFICATION

17.3 Rows: Pressure release valves in pocket filter shall be provided in rows in the
   bed and slope of canal. The number of rows depends on bed width, depth,
   drainage media, size of valve and sub-grade.

17.4 However, for general guidance numbers of rows on the bed of canal are to be
   such that for every 10m bed width one row shall be provided. Minimum numbers
   of rows for width. 10m and above shall be two and for less than 10m shall be
   one. The number of rows shall be so arranged as to be symmetrical in plan with
   reference to centre line of canal. On the sides in general, one row at every 4m
   should be provided. The first row should be about 50cm above curve line and top
   row at 50 cm to 100 cm below full supply level. If the water depth is less than 1.5
   m one row should be adequate. Valves in adjacent rows should be staggered.

17.5 Spacing : For general guidance, one pressure relief valve for every 100 m2
   should be provided in the canal bed, while on the sides, one pressure relief for
   every 40m2 should be provided. However, the pracing should be decided on this
   general consideration, keeping in view the site conditions.

17.6 Construction : Pockets shall be excavated (Fig. 6) with their sides as nearly
   vertical as possible. Pockets on slopes shall be excavated with their sides at right
   angles to the slopes. Any material outside the lines or required excavation which
   is disturbed shall be removed.
         Note : The graded filter shall be designated in such a way that there is no loss
         of soil particles. The gradation curve of bed material should be obtained from
         the sieve analysis. The 15 percent size (D15) of the layer (A) should be at
         least four times as large as 15 percent size of the soil and less than 4 times
         85 percent size D85 of the soil. Design of the other layer should be designed
         in a similar way till the requirement of the filter opening is met.

17.7 Graded filter meeting the requirements as sown in the above figure shall be
   carefully placed and compacted to form an even bedding upto the elevation of the
   bottom of canal lining. The gravel shall be clean and well graded.

17.8 Any suitable material such as tar paper shall be placed over the entire surface
   of the broken rock or gravel fill to prevent water from concrete entering the fill.

17.9 Pressure relief valves should be provided on the longitudinal/transverse
   drains (see Fig. 9) and on slopes, if there are no transverse drains. The PRV may
   be provided in pockets filled graded filter underneath the lining. Pockets may be
   square with sides 800 mm or cylindrical with diameter 600 mm.

17.10 Pockets on slopes should be excavated with their sides at right sides at right
   angles to the slope. The PVC perforated housing pipe for the PRV should be 750
   mm long for sides and 430mm long for bed and should conform to Class-2 of IS:
   4985:1988. It should be placed in the centre of the pocket. Graded filter as shown
   in Fig. 6 should then be carefully placed in the pocket and compacted to form an
   even bedding for canal lining. Perforations in the housing pipe should be as
   shown in Fig. 7.

17.11 Longitudinal and Transverse Drains :

         (a) Longitudinal drains : This section of the drain should be trapezoidal with
         bottom width 500mm, depth 525mm and with suitable side slopes. The drain
         should be carefully filled up to the bottom of the lining with graded filter as
         shown in Fig. 8 and properly compacted so as to form an even bedding for
         the lining. The pipe may be Asbestos Cement pipe or PVC pipe. It should be

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TECHNICAL SPECIFICATION

         perforated. Usually 150mm dia pipes are used. The perforations/holes should
         be 12mm in diameter and should be done by drilling. On an average there
         should be minimum of 100 perforations/holes per metre length of pipe and the
         perforations/ holes in adjacent rows should be staggered. The pipe should be
         properly surrounded with suitable filter. Care should be taken that the filter
         does not get clogged during lining.

         (b) Transverse drains : Transverse drains, where necessary, should be
         provided in the bed and on the side slopes upto free board level. Section of
         transverse drains should be same as of longitudinal drains shown in fig. 8.
         The drain should be carefully filled up to the bottom of the lining with graded
         filter as shown in Fig. 8 and properly compacted so as to form an even
         bedding for lining. The pipe may be Asbestos Cement pipe or PVC pipe. It
         should be perforated. Usually 150mm dia pipes are used. The
         perforations/holes should be 12mm in diameter and should be done by
         drilling. On an average there should be a minimum of 100 perforations/holes
         per metre length of pipe and the perforations/holes in adjacent rows should
         be staggered. The pipe should be properly surrounded with suitable filter.

       (c) Spacing of Drains : Spacing of longitudinal drains shall be as indicated in
       Table-4.
                                          Table – 4
Canal Bed width                    No. of Drains
Less than 10m                       One central drain
10m and upto 20 m                  Two toe drains
Above 20m and upto 30m             One central and two toe drains
30 m and above                     One for every 10m width arranged
                                   symmetrically with the centre line of canal.

         The spacing of transverse drains shall be at every 10-15 metres depending
         on sub-grade.

         (d) Rows : Criteria for fixing the number of rows shall be same as given in
         Clause 17.3 and 17.4.

         (e) Outlets : Outlets shall be provided through suitable concrete boxes
         collecting water from drains with pressure relief valves on the top of the boxes
         shown in Fig. 10. These boxes shall be of precast cement concrete, open at
         the top and with a circular cross section. The inner diameter and depth of
         boxes shall be about 450mm and 600 mm respectively. These boxes shall be
         filled with graded filter material.

         (f) Spacing of outlets : On each drain exit, a pressure relief valve shall be
         provided at a spacing of 100m or as specified. Outlets on adjacent drains
         shall be staggered.

         (g) Construction of Under Drains with Open Joints : Trenches for under
         drains shall be excavated to not less than the dimensions specified in para
         17.11 with the sides of the trenches as nearly vertical as practicable. Any
         material outside the lines of required excavation for trenches which is
         disturbed shall be removed.

         (h) Broken rock or gravel shall be carefully placed and compacted to form an
         even bedding, up to the invert level of pipe or drain and so as not to disturb
         the pipe after being laid and to held it securely in position. The pipe or drain
         shall be laid nearly in the centre of trenches with partially open uncemented


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TECHNICAL SPECIFICATION

         joints. The entire trench outside the pipe shall be filled with broken rock or
         gravel graded filter upto the elevation of the bottom of the concrete canal
         lining. Broken rock or gravel used in back filling trenches for under-drains
         shall be clean and well graded with sizes from 4.5mm to 12.5 mm.

         (i) Any suitable material, such as tar paper shall be placed over the entire
         surface of the broken rock and gravel fill to prevent water from concrete
         entering the fill in case of cast in situ concrete lining.

         (j) Under Drains for Clayey Sub-Grade : For clayey soil a 7.5 cm or as
         specified thick layer of sand or suitable filter material shall be provided
         underneath the lining. Rows of pipes with open joints in gravel filled trenches
         with outlets as specified in Clause 17.11(c) shall be provided. Other details of
         drains, outlets and construction shall be according to Clause 17.11(a),
         17.11(f).

         (k) Under drainage for CNS Material : Wherever cohesive non swelling
         (CNS) layer is provided, the permeability of CNS layer will decide drainage
         provisions considering CNS layer as sub-grade. Provisions of CNS layer be
         made in accordance with Clause 7.


18       USE OF POLYETHYLENE FILM UNDER RIGID SURFACE
         LINING OR SOIL COVER
18.1     A plastic membrane of low density polyethylene film of suitable thickness may
         be used below the concrete lining in sides and in beds where the sub-grade
         of the lining is of pervious materials like murum etc., so as to prevent
         absorption of water in subgrade from green concrete, during placement on
         the subgrade. However, the Superintending Engineer shall decide whether
         the polyethylene film shall be used or not in the case of every individual work.

19       FILM
19.1     The low density polyethylene film should conform to IS: 2505:1984 and be of
         nominal thickness not les than 150 microns (thickness to be designed, based
         on type or subgrade and water depth) and should be black in colour.

19.2     The film shall be uniform in colour texture and finish. The material shall be
         substantially free from pin holes and undispersed raw materials, streaks and
         particles of foreign matter. There shall be no other visible defects, such as
         holes, tears or blisters. The edges shall be free from nicks and cuts visible to
         unaided eye.

19.3     The film shall be furnished in the form of flat, sheet or rolls or in the form of
         flat tubing or in any other specified form as agreed to between the suppliers &
         the purchaser. The film shall be free from any objectionable colour.

20       GRADES
20.1     The film shall be classified according to the optical properties, impact strength
         and slip. Each grade shall be designated by a set of 3 numerals.

20.2     The first one will indicate optical property. The second impact strength and
         the third slip property. Wherever numeral “Zero” is used, it shall mean the
         material has not been tested for that particular property.

                                                                                      159
TECHNICAL SPECIFICATION

20.3     For typical properties the numeral 1. shall mean low clarity, numeral 2. normal
         clarity and numeral 3. high clarity. For impact strength 1. shall indicate low
         impact strength, numeral 2. normal impact strength and numeral 3. high
         impact strength. For slip property numeral 1. shall denote low slip, numeral 2.
         medium slip, numeral 3. high slip and numeral 4. shall mean extra high slip.

20.4     Example :-

             Grade 001 –       This shall mean that the film has not been tested of
                               optical properties and impact strength and it is of low
                               slip.
             Grade 210 -       This shall mean that the film is of normal clarity, low
                               impact strength and slip has not be tested.
             Grade 314 -       This shall indicate that the film of high clarity, low
                               impact strength and extra high slip.


21                PREPARATION OF SUB-GRADE
21.1     The subgrade preparation shall be as per provisions under Clause 4
         Additional requirement for this shall be as detailed hereunder.

21.2     Kankar or any sharp angular material shall be removed to provide reasonable
         smooth subgrade. Any weeds roots and vegetation that may damage the film
         shall be removed.

21.3     If the reaches are weed infected suitable anti-weed treatment of the sub-
         grade may be done to discourage weed growth under the film. The
         weedicides should be selected with utmost care specially where the canal
         water is used for drinking/bathing purpose and should not be harmful.

21.4     After completion of the spraying of weedicides and before taking up the next
         activity, a period of 24 hours should be allowed for penetration of chemicals
         into the soil.

21.5     A layer of fine sand of thickness 12mm to 25mm should be provided over the
         subgrade (in bed only) to facilitate working conditions over the film. As there
         is no bound between concrete & LDPE film, the canal profile should not be
         smoothened (with a layer of sand etc.) as the undulations will form keys &
         prevent sliding tendency of concrete.

22       LAYING TECHNIQUE
22.1     The film shall be laid over the sub-grade prepared below the designed bed
         level to the extent of cover thickness in strips perpendicular to water flow
         depending upon the width of the film, width of the bed & perimeter of the
         section. Longitudinal joints should be avoided.

22.2     The film shall be spread loosely over the sub-grade so that it shall attain the
         contours of sub-grade and compensate for thermal variation during the day. It
         is recommended that an extra length of 3.5 percent over the length of the film
         required for spreading over bed and side slopes should be provided to take
         care of thermal variations during the day.

22.3     As polyethylene film is likely to be affected by very high temperature of about
         45oC obtaining in summer days it would be advisable to avoid laying of the


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TECHNICAL SPECIFICATION

         film under such high temperature. In case it is necessary to continue the work
         on hot days as well, working should be restricted to morning hours only.

22.4     Adjacent layers of film sheet should be laid in such a manner that the width of
         an overlap should be adequate and the overlap should point downstream.
         The film sheets should be jointed using of the methods described in 22.4.2 to
         22.4.3.




                                                                                    161
TECHNICAL SPECIFICATION

22.4.1 Jointing of Film Sheet : There are various methods of jointing adjacent
       lengths of film sheet to avoid leakage along the joints. The suitability of a
       particular method depends on prevailing site conditions.

22.4.2 Simple Over lapping : The method of over lapping is shown in Fig. 11(i). The
       simple over lap should not be less than 30 cms for earth cover and 15 cms for
       hard cover. Since the simple overlap is prone to leakage it is least preferred,
       yet it can be adopted for small channels.

22.4.3 Folded overlapping : The methods of folded over laps are generally used in
       practice. The first type is the simple folded over lap as shown in Fig. 11(ii). In
       this the fold should not be less than 7.5 cms. In the second type folded over
       laps are embedded in a trench having a minimum width of 30 cms and depth
       of 15 cms as shown in Fig. 11(iii). After the over lapping the trench should be
       filled with excavated material or cement concrete and coping provided over it.

22.4.4 Jointing by hot bitumen : The film sheet can also be jointed by a coat of
       bitumen. Bitumen of the grades 85/25 and 80/100 in the ratio of 2:1 should be
       heated at a temperature around 100oC. Heated bitumen can be tested on a
       small piece of film sheet so that overheated bitumen may not damage the
       film. After ascertaining the appropriateness of the temperature, apply a thick
       coat of tested bitumen on a 10 cm area along the width of both the sheets
       and fold them as shown in Fig. 11(iv) and cover the same with brick masonry
       profiles (Dhamalies) at a suitable interval depending upon the width of the film
       which should come directly over this joint at a regular intervals, in order to
       ensure a better joint of the film sheet. Using damaged fill sheet is not
       recommended. However, this method has been found convenient for
       repairing punctures in the film at site itself. In case of big holes, pieces of
       sheet should be pasted from both sides.

22.4.5 Sealing by adhesive tapes : Adjacent lengths of film sheet can also be
       jointed with suitable adhesive tapes as shown in fig. 11(v). Hydrostatic
       pressure and the over layer is sufficient to make the over lap practically water
       tight. However, in the areas where high temperature exists (40o – 50oC)
       during summers and with passage of time under submerged conditions, the
       joints may open up. Soil particles creeping into the joint while laying may also
       lead to leakage.

22.4.6 Heat Sealing : As shown in Fig. 11(vi) the overlap joints can be heat sealed
       with a hot iron. The temperature of the iron should be adjusted and
       maintained at 150oC and pressed on the film sheet joint over lap for 4
       seconds for a 150 micron film thickness sheet. For every 50 micron increase
       in the film sheet thickness, the time would be increased by one second. To
       avoid the risk of film/sheet sticking to iron a poly-tetra-fluoroethylene (PTFE)
       impregnated glass cloth or Teflon sheet or Cellophane sheet should be
       placed between the film and the iron.
         Note : Heat sealing is the most effective of all the methods.

22.5     In all type of joints the over lap should be kept normal to the flow and should
         point downstream of the canal.

22.6     Film sheet should be spread on well prepared subgrade and should be held in
         position at two extremities of the bed by placing excavated earth on it, while
         two ends of film sheet are being loosely held over the embankment.




                                                                                     162
TECHNICAL SPECIFICATION

22.7      Extra length of film sheet should be placed in trench at embankment top and
          covered with earth. The embankments may be then raised to designed level.

22.8      Excavated earth should be placed over the film sheet to build up the canal
          section. The earth layer should be compacted by using light rollers and
          manual templates. It may be so arranged that earth from over excavation of
          an adjacent section be used for covering the film sheet in the earlier section.
          Thus, by the time earth cover is provided in one section, the adjacent section
          is ready to receive film sheet lining.

22.9      The film/sheet on the bed should be covered first. To avoid any damage to
          the film/sheet a layer of earth, free from gravel or granular material, should be
          laid and compacted over the film.

22.10 The remainder of the earth cover should be spread in 15 cm layers, watered
      and compacted using light rollers or manual templates.

22.11 Connection to structures : In case of structures in lined channels film
      should be embedded in the solid structure, i.e. R.C.C./Masonry by about 15
      cm to provide impermeable layer. This film should be protected by layer of
      50mm to 100mm thick cement concrete.

22.12 Top Cover : The top cover may be an earth layer of suitable thickness or of
      pre cast concrete tiles, In situ Cement Concrete, Stone Slab (See IS:
      3873:1993), or burnt clay tile (See IS: 3872-1992).

22.13 Earth Cover :
      (a) For canals with velocities less than or equal to 0.6 m/s, minimum
          thickness of cover over the film sheet should not be less than 30 cm in
          bed and 60 cm on the sides.
      (b) For canals with velocities more than 0.6 m/s, the film/sheet on the bed
          should have a rigid cover against possible bed erosion. For sides the
          cover should be of any rigid type.
      (c) Side slopes should be designed in accordance with the stability
          requirements with lining in position. Side slopes not steeper than 1.5:1 are
          recommended.
      (d) If the cover material contains kankar or sharp angular material, a cushion
          layer 7.5 cm thick of sieved earth (free from kankar, etc.) may be provided
          over the film sheet.
      (e) To prevent effect at the water line, kankar or gravel of stone aggregates of
          size 4 to 5 cm may be spread over the cover prior to compacting, using
          light roller or manual ramming.

22.14 In case of cement concrete lining the concrete should be so placed that the
      aggregates do not puncture the film sheet.

22.15 For a better bond between the smooth surface of film sheet and rigid cover
      lining, cement slurry may be sprayed over the film sheet before placing the
      rigid lining.

22.16        Do’s and Don’ts for Geo-membrane for Canal Lining .
   (1)           Keep the rolls in original packing prior to actual use of laying and see
             at the time of delivery that the rolls are packed properly.
    (2)          Apply uniform pressure while thermal welding (heat sealing) the film
             sheet.
    (3)          Don’t leave unpacked rolls exposed to over prolonged periods or
             preferably store them indoors.


                                                                                       163
TECHNICAL SPECIFICATION

    (4)           Don’t rough-handle or drag rolls, as the film sheet may get damaged
             in the process.
    (5)           Don’t let workers walk on the film sheet while the lining operation is in
             progress to avoid puncturing of the film sheet, in case this is unavoidable,
             they should walk bare foot.
    (6)           Don’t slide cover material like bricks etc. on film/sheet to avoid
             damage and displacement.
    (7)      Don’t use hooks for lifting the rolls.

23 CAST IN SITU CEMENT CONCRETE LINING
23.1      Cement Concrete : Cement concrete of specified mix shall be provided at
          places as shown in the drawings. The specifications for cement concrete shall
          be in accordance with the one laid down in relevant specifications.

23.2      Preparation of Sub-Grade : The sub-grade preparation shall be as per
          provisions under Clause 4.4 as applicable.

24 LAYING OF CONCRETE LINING :
24.1 Slump : For hand placing and for placing with the light machines where
   concrete is screeded from bottom to the top of the slope, the consistency shall be
   such that the concrete will barely stay on the slope. A slump of 60 to 70 mm shall
   be generally allowed. For heavier longitudinally operating slip-form machines, a
   slump of 50 mm at the laying point shall be permitted. To have a close control of
   consistency and workability of the concrete the slumps of concrete shall not vary
   by more than 20 mm which would otherwise interfere with the progress and
   quality of the work.

24.2 Thickness : The thickness of lining should be fixed depending upon the
   nature of the canal requirement, namely hydel channel or irrigation channel, full
   supply depth and channel capacity. Hydel channel should have a greater
   thickness than channels meant for irrigation because of draw down effects and
   where closure for repairs may not be useful. Deeper channels should have a
   greater thickness than shallow depth channels. Minimum thickness of canal lining
   based on canal capacities are given in Table 5.
                            Table 5. Thickness of In-Situ Concrete Lining

       Capacity of Canal              Depth of water              Thickness of Lining
               1                            2                             3
          (Cumecs)                         (m)                          (mm)

              0-5                           0.1                          50-60
              5-50                         1.25                          60-75
             50-200                       2.5-4.5                        75-100
            200-300                       4.5-6.5                       100-120
            300-700                       6.5-9.0                       120-150

Note : If surface deterioration in freezing climate is expected, these thicknesses may
       be increased. The lining will not be subjected to external hydrostatic earth
       pressures or uplift caused by expansive clays on frost heave.




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TECHNICAL SPECIFICATION

25 TOLERANCE IN CONCRETE THICKNESS, ALIGNMENT
   AND GRADE :
         (a)      Departure from established     =     + 20mm on straight reaches,
                   alignment                           50mm on partial curves          or
                  tangents
         (b)      Departure from established     =     + 20mm on small canals.
                  Grade.
         (c)      Variation on concrete lining   =     + 10mm provided average
                  thickness                            thickness is not less         than
                  specified
                                                       thickness.

26 MIXING
26.1     Concrete should normally be mixed in a mechanical mixer.

27       PLACING
27.1     Placing of concrete should not be started until all form work, installation of
         parts to be embedded and preparation of surfaces upon which concrete is to
         be laid have been completed. All absorptive surfaces against which concrete
         is to be laid should be moistened thoroughly so that moisture will not be
         withdrawn from freshly placed concrete. The surfaces however, should be
         free from standing water and mud and 1:3 cement slurry shall be spread over
         the moist sub-grade before placing concrete to prevent absorption of water
         from concrete making it spongy. A plastic membrane of low density polythene
         film of suitable thickness may be used below the concrete lining in sides and
         in beds where the sub-grade of the lining is of pervious materials like murum
         etc, so as to prevent absorption of water in sub-grade from green concrete,
         during placement on the subgrade. The approved film is to be laid on the
         neatly well-dressed subgrade, and fixed in the subgrade so as to prevent
         displacement during the placement of the concrete. The use of polythene
         sheets is for achieving better ultimate imperviousness of the lining as a whole.
         The following properties of L.D.P.E. film are given is guidelines with deviation
         to the extent of (plus or mius) 10 percent.
                (1)    Tensile strength      =       17.5 N/mm2
                (2)    Tear resistance       =       9.5 N/mm2
Note : Till better materials are developed, use of LDPE film of appropriate strength
       and resistance against slippage of tunnel may be adopted as a second line of
       defense against embankment failure and as a seepage barrier particularly in
       high capacity channels of relatively bigger depth.

         In case filter material is to be provided over subgrade to take care of different
         hydrostatic pressure and draft down in canals, designs of coarse filter
         material, blanket immediately in contact with lining would be necessary. To
         make such filter blanket effective and to prevent ingress of concrete into it,
         before placement of necessary. To make such filter blanket effective and to
         prevent ingress of concrete into it, before placement of concrete polythene
         sheet should be placed over the filter blanket. All concrete should be placed
         directly in its final position within 20 minutes of mixing. Concrete should not
         be dropped from excessive height and free fall should be kept to a minimum
         to avoid segregation. Construction should be continued until satisfactory
         construction joint is made. Concrete should not be placed faster than the
         placing crew can compact properly.


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TECHNICAL SPECIFICATION

28 HAND PLACING OF CONCRETE
28.1     Hand placing of concrete should normally be adopted where cheap labour is
         available.

28.2     Depending upon the construction method and arrangement of concreting the
         sequence of placing concrete either on the sides or the bed should be
         decided. It is preferable to place concrete on the sides first if the the
         concreting equipment and the construction materials like aggregate, sand etc.
         are kept on the canal bed. This will prevent the bed from getting spoiled by
         the subsequent concreting operations for the sides. Other things being equal
         placement for bed first should be preferred.

28.3     The concreting of the sides and bed should be done in alternate panels. The
         panel width should vary from 2 to 3m. In no case should the panel width
         exceed more than 3m as wider bays require unwieldy vibrators for
         compaction. The construction joints should be either parallel or perpendicular
         to the direction of flow. In case the full supply depth is high, construction joints
         along the direction of flow to divide the length of the panel should be
         provided. For this purpose wooden rafters should be used. The succeeding
         panels should be laid at an interval of one day. If the sloping length is less
         than 2.5 to 3 metres, concrete should be placed in one operation over the
         entire length. In case of deeper canals where the sloping length is more it
         should be suitably divided (say for a length of about 2 metres) in each
         alternate panel so as to prevent appreciable downward flow of concrete.

28.4     The bays/panels should be formed by proper form-work of M.S. channels laid
         all around the bay. The channels should be firmly spiked to the subgrade so
         that no movement takes place at the time of concreting and vibration. The
         depth of the M.S. channels should correspond to the required thickness of
         concrete lining. The concrete should be dumped in the bay from bottom to top
         and then spread all over the bay uniformly and for the required thickness
         guided by the channels. The spread concrete should then be compacted
         properly and thoroughly by means of mechanical or screed vibrators. An
         improved plate vibrator operated by high horse power engine and a which for
         moving the vibrator up the inclined slope should be made use of for proper
         compaction. When width of panel is less i.e. upto 2m manual operation of
         vibrators is possible and may be permitted. In no case the concrete should be
         compacted by tamping. The compacted surface should be true to the required
         side slope. Before re-using the channel forms, they should be thoroughly
         cleaned and well oiled. Care should be taken while placing and vibrating the
         concrete that, the subgrade in the adjacent bays does not get spoiled.

28.5     For bed lining the procedure for laying the concrete on the canal beds should
         be same as that for side lining except the operations specifically required on
         sloping surfaces. The compaction should be done by means of a heavy
         screed vibrator moving on the side channels.

28.6     In order to test the effectiveness of vibration, permeability and strength of
         concrete cores at suitable places from the side as well as from the bed
         concrete should be taken.

28.7     In situ sleeper in case of bed, and precast in case of sides, should be
         provided under the joints. The sleepers should be 20cm wide and 15 cm
         deep. The sleepers should be placed centrally below the joint. Concrete used
         for sleepers should be of the same grade as for lining. Alternatively brick
         sleepers 225 x 150mm with 1:4 mortar may be used. Concreting near the

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TECHNICAL SPECIFICATION

          joints should be done with utmost care so as to avoid segregation and
          collection of loose pieces of aggregate along the form work which may later
          result in honey combing.

28.8      Concreting near the junction of the side concrete and bed concreting should
          be done such that both should rest firmly against each other to resist any
          back kick from external hydrostatic forces (Fig. 12 and 13). The sketches
          indicate the procedure for formation of junction of the sides with bed
          depending upon the sequence laying concrete i.e. sides first and vice-versa.

29 MECHANICAL PLACING OF CONCRETE
29.1      Concrete for slip form should be air entrained to provide a more workable and
          slipable mix. Percentage of air should as follows:-

                      Maximum Aggregate size              Air, Percent by Volume
                              mm                                     %

                                 10                                 8.0
                                12.5                                7.0
                                 20                                 6.0
                                 25                                 5.0
                                 40                                 4.5

          Air entraining agents will always be used in concrete by means of slip form
          paving machine for entraining air.

    (a)      Subgrade guided slip form : This should be used for lining small to
             moderate size canals. The slip form should be supported directly on the
             subgrade and operated longitudinally along it, concrete should be
             screeded on the bed along the canal and on the sides from to top.
    (b)      Rail guided slip form : They are adopted for larger canals of considering
             length. Slip forms supported on rails placed along both berms of the
             canals should be operated longitudinally. Concrete should be spread
             uniformly on the bed longitudinally and on the sides from bottom to top.

          PROCEDURE FOR LAYING CONCRETE IN PANELS :

          The concrete of lining in panels shall be placed in manner prescribed in para
          33.4 as specified.

30 FINISHING
30.1      The surface of concrete finished against forms should be smooth and should
          be free from projections, honey combing and other objectionable defects.
          Immediately on the removal of forms, all unsightly ridges or lips should be
          removed and undesirable local bulging on exposed surfaces should be
          remedied by tooling and rubbing. Repairs to concrete surfaces and additions,
          where required, should be made by cutting regular openings into the concrete
          and placing fresh concrete to the required lines. The chipped openings should
          be sharp and should not be less than 70mm in depth. The fresh concrete
          should be reinforced with wire mesh extending to the full depth of the slab
          and chipped and trowelled to the surface of the opening. The mortar should
          be placed in layers not more than 20 mm in thickness after being compacted
          and each layer should be compacted thoroughly. All exposed concrete


                                                                                   167
TECHNICAL SPECIFICATION

         surface should be cleaned of impurities, humps of mortar or grout and
         unsightly stains.

30.2     The concrete should be finished to an even and smooth surface free from
         pockets, voids or exposed aggregates. This should be obtained by careful
         use of a long handled steel trowel. Any remaining roughness or rough spots
         shall be rendered smooth, without any time interval after laying the concrete,
         with cement mortar of 1:3 proporation.

31       CURING
31.1     Subsequent to laying of concrete lining and after a period of 12 hours or as
         earlier as warranted by site conditions, the lining should be cured for at least
         28 days.

31.2     Bed lining: Twelve hours after laying of concrete, small bunds longitudinal
         and cross wise consisting of earth materials or lean mortar (1:15) should be
         laid for a height of 8 cm for the purpose of curing. Water will be kept always
         ponded in these bunds for 28 days continuously.

31.3     Side lining: The panel in which concreting is done on the previous day
         should be covered with burlap or empty cement gunny bags.

31.4     For the purpose of curing, water tank of 5000 litres capacity should be placed
         on a platform at the edge of service road at the rate of one for 500m length of
         lining, which should be kept filled with water with arrangement of outlet and
         flexible hose of at least 300m length. Water should be continuously sprinkled
         on the curing of side slope may be done by constructing masonry drains with
         weep holes or perforated pipes on the coping at the top of lining or by
         sprinklers.

32       SURFACE DRAINAGE
32.1     The top of the side lining concrete should be keyed into the subgrade both in
         cutting as well as banking by taking it horizontally for a width of about 300mm.
         This key would prevent direct entry of surface rain water behind the lining.
         The top surface of the key should be finished with downward slope of 1 in 10
         or so towards the canal. A day after completion of concreting of all panels
         between two templates, concreting of key slab should be done.

32.2     Concurrently with the curing operation, surface drainage arrangement of the
         bank such as construction of keys, bank surface slope away from the lining
         and construction of longitudinal drain on the outer edge shall be completed.
         This is necessary to prevent surface and subgrade erosion and consequent
         damage to lining.

33 JOINTS
33.1     Expansion Joints: These should not be provided except where a structure
         intersects in the canal. The details are given in relevant Indian Standards
         covering such structures.

33.2     Construction Joints: Construction joints from a work link in the lining and
         deterioration is generally noticed at such joints. Besides joints are potential
         seepage points for the canal water. As such number of joints should be kept
         to the minimum and great care should be taken to obtain well compacted and


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TECHNICAL SPECIFICATION

         smooth concrete surface at joints. To ensure a good surface the shuttering
         should be smooth, cleaned, well oiled and rigidly fixed at site. Besides
         different mechanisms for compaction of concrete in lining, tamping with iron
         bar near the joint surface gives better results.

33.3     To cater for initial shrinkage and cracks, concreting should be done in
         alternate panels or bays. The panel size for the bed and slope of the canal
         should be adopted as given in 25.6.3.6. A 25 cm wide L.D.P.E. film of 150
         micron thickness should be placed on the top of sleepers, provided to support
         construction joint. The top of film and side of panel should be applied with
         primer conforming to IS: 3384-1985. This sheet acts as an intercepter for
         seepage through the joint. In case lining is laid by mechanical paver, PVC
         water stops are placed at joints along with the concreting. The water stops in
         such a case should be provided at a spacing not more than 4 metres centre
         to centre.

33.4     Laying of Precast Concrete Tiles


33.4.1 The tile should conform to IS: 10646:1991).

33.4.2 The lining should be started only when at least 35 m length of canals
       subgrade is properly dressed to receive lining. The arrangement for mortar
       and availability of sufficient number of tiles should be ensured before starting
       the work. Arrangement for proper soaking of the files shall be made.

33.4.3 The subgrade should then be uniformly soaked with water without making it
       slushy to ensure that water penetrates to a depth of about 300 mm in sandy
       soil and about 150 mm in other soils. Wetting of subgrade should continue in
       advance of laying of tiles so that soil does not absorb moisture from the
       mortar laid on the subgrade on laying the layer of tiles.

33.4.4 Single tile profile of lining parallel to central line of the canal should be
       prepared at suitable intervals. Mortar (1:3) should uniformly be spread over
       subgrade for a minimum thickness of 12 mm and the tiles should be properly
       laid in position quickly. It should be ensured that vertical joints are completely
       filled with mortar. The tiles should be laid in bed with their lengths at right
       angles to the central line of the canal while on the other side slopes they
       should be laid parallel to the central line.

33.4.5 Tiles should be firmly embedded in mortar. However, if any, should be
       rectified by relaying defective portion with fresh mortar. The tiles should be
       laid over a minimum of 12 mm thick cement mortar and having aggregate less
       than 6 mm to bring overall fineness modulus less than 2. Hollow joints should
       be raked and pointed with the same mortar. The thickness of joint should not
       exceed 12 mm.

33.4.6 Slab should be firmly embedded in mortar. Hollows if any should be rectified
       by relaying the defective portions with fresh mortar.

33.4.7 On completion of laying lining should be kept wet by sprinkling water over it to
       keep the mortar wet. On the next day, the surface should be kept wet and
       joints should be carefully wetted. Hollow joints should be raked to a depth of
       12 mm, loose mortar removed from sides and top of tiles and the joints
       properly refilled. Loose tiles should be removed and relaid. Curing of Mortar
       joints after laying shall be ensured for 14 days. Satisfactory curing can be


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TECHNICAL SPECIFICATION

         achieved by covering the joints with soaked gunny bags (burlap) & keeping
         the same wet for 14 days.

33.4.8 The complete lining should be checked for level with wooden templates and
       spirit level.

34       SAFETY LADDERS
34.1     Safety ladders should be constructed in canal lining as directed by the
         Engineer-in-Charge.

34.2     Safety ladders consisting of ladder rungs should be constructed in canal lining
         about 30m upstream of the point where the canal enters some underground
         structure. In other reaches safety ladder may be provided at a spacing of
         about 300m; the ladders being provided alternatively on either side.

34.3     Ladder rungs should be smooth, round mild steel bars, galvanized or coated
         with coal tar after installation. Typical details of safety ladder are illustrated in
         Fig. 14.

34.4     As an alternative to safety ladders, steps of rise 150mm, tread 300mm and
         1500mm wide may be provided in plain cement concrete of grade M-10 at a
         spacing of 300 m centre to centre (staggered) on either side of canal. Details
         of the steps are illustrated in figure-15.

35 PRECAST CEMENT CONCRETE LINING
35.1     Scope of work
         The work covered under this section consists of lining the sides including
         manufacturing of PCC slabs including cost of all materials, Construction of
         platforms for manufacturing of PCC slabs, construction of curing ponds,
         curing stacking, conveyance to the site and also laying lining including cost of
         cement mortars, pointing as directed by the Engineer-in-charge.
         Precast lining the sides of the canal with precast cement concrete slabs of
         size 550x550x 50mm. or any other size specified by the Engineer,
         manufacturing the slabs using a cement content of 250kg./cum. giving a
         28days characteristic compressive strength specified based on laboratory
         tests using 20 mm. maximum size hard broken machine crushed metal
         obtained of approved quality including cost and conveyance of all materials,
         form work, machine mixing, air entraining agents, laying, vibrating, curing of
         PCC slabs and conveyance of slabs to work site, handling laying slabs over
         a bed of 12.5mm thick cement mortar (1:5), using not less than 3.75kgs. of
         cement per one square meter for first layer and 10mm. thick cement mortar
         (1:3), using not less than 6kgs. of cement per one square metre for second
         layer and fixing the P.C.C. slabs in 6mm. thick cement mortar (1:3)using not
         less than 3.6 kgs. of cement per one square metre including curing the lining
         and all other operations necessary to complete the finished item of work as
         directed by the Engineer-in-charge, for side lining of canal.

35.2     Slump
         : The amount of water used in the concrete shall be changed as required to
         secure concrete of proper consistency and to adjust for any variation in the
         moisture content or grading the aggregates as they enter the mixture.
         Addition of water to compensate the stiffening of the concrete resulting from
         over mixing or objectionable drying before placing shall not be permitted.


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TECHNICAL SPECIFICATION

         Uniformity in consistency from batch to batch shall be required. To have close
         control of consistency and workability of the concrete, the slump of concrete
         shall not vary more than 20 mm. which would otherwise interfere with the
         aggregate and quality of the work.

36 MANUFACTURING P.C.C. SLABS:
36.1     Construction of platform and curing ponds: P.C.C. Slabs are cast at one or
         more places as directed by the Engineer-in-charge and transported to the site
         of construction after curing as needed. A cement concrete platform shall be
         constructed for manufacturing centres making it into required compartment to
         manufacture the required P.C.C. Slabs per day in a compartment. The other
         compartments shall be used for the other days work by using the same
         moulds used on the 1st day curing pond should be constructed adjacent to
         the platforms for curing the P.C.C. Slabs. The platform and curing ponds shall
         be constructed preferably at a central place of the work site or at a place as
         directed by the Engineer-in-charge. The land required for platform, curing
         ponds, stock yard, manufacture yard shall be acquired by the contractor at his
         cost. Construction of curing ponds and platform shall be at the expense of the
         contractor and no extra payment will be made for their construction. The rates
         quoted by the contractor shall include the cost of construction of curing ponds
         and platform.

36.2     Moulds : Adequate no. of steel moulds shall be procured for casting P.C.C.
         Slabs of sizes 550x550x50mm. as indicated in the drawing or as directed by
         the Engineer-in-charge.

36.3 Casting of P.C.C. Slabs : The edges of the moulds shall be cleaned, and
   burnt oil shall be applied to the inner edges of the moulds and the platform.
         The mould shall be arranged in rows keeping sufficient way for walking and
         working between the moulds and rows. The machine mixed concrete shall be
         placed only in the presence of an authorized representative of Engineer. The
         concrete shall be placed and compacted before setting commences. The
         method of placing should be such as to        preclude segregation. The size
         and shape of the slabs grooved can be varied by the use of different moulds.
         The slabs shall have all sides and faces true and square and shall be at right
         angles to the faces to each other. Proper consolidation of concrete in the
         moulds through provision of “shaking tables” (vibration table) is essential.
         The moulds shall be straight and sufficiently strong so that while concrete is
         laid and vibrated, they retain their shape having neat and straight edges when
         the moulds are removed.
         All exposed concrete surface shall be cleaned of from impurity, lumps of
         mortar of grout and unsightly stains. The finished surface shall be equivalent
         in evenness, smoothness and free from pockets and surface to that
         obtainable by effective use of long handed steel trowel. The P.C.C. slabs thus
         manufactured shall be stacked after curing at the stock yard on edge
         vertically on a level ground over 50mm. saw dust or husk so as to avoid
         damage to edges. Packing not less than 12 mm. thick with saw dust or husk
         shall also be given in between- slabs at stock yard. Stacking and packing
         shall be to the satisfaction of the Engineer-in-charge.
         The slabs shall be provided with tongues and grooves as given below.
            i.    A tongue on one side and groove on the opposite side of the slab shall
                  be provided in the middle of the side running through out the length of
                  that side.


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TECHNICAL SPECIFICATION

            ii.    The tongue shall be a projection with a semi circular cross section of
                   radius 13mm.
           iii.    The grooves shall be a depression with semi circular cross section of
                   radius 12 mm.
           iv.     The position of tongue and grooves shall be similar on all the slabs
                   with respect. to each other.

37 CURING:
37.1     After 24 hours of casting the P.C.C. slabs, the moulds shall be removed and
         the slabs shall be kept in the curing ponds for atleast 28 days for curing. After
         curing P.C.C. slabs shall be taken out of curing ponds, stacked carefully for
         use as directed by the Engineer. After about four to six hours of casting, the
         moulds shall be properly covered by the Hessian cloth rolls which are to be
         kept continuously wet till the moulds are removed and P.C.C. slabs are put in
         the curing tanks (moulds to be placed in shed).

38       TESTING OF CONCRETE AND ACCEPTANCE
38.1     The permissible tolerance on the length and width shall be as follows:
                                      for Slabs                                     for Slabs
                                       550x550x50mm.
550x275x50mm.
         In the length                   + 3mm                                                    + 3mm.
         In the width                    + 3mm                                                   +1.5mm.
         In the diagonals              + 4.50mm.                                                 +2.25mm.
         In the thickness              + 2mm.                                                     + 2mm.
-------------------------------------------------------------------------------------------------------------
         The contractor shall provide all facilities and cooperation towards collection of
         samples, cores etc., and shall be present at the time when samples, cores
         etc., are taken. The tests shall be carried out at the testing laboratories setup
         at the site or any other laboratory that the Engineer-in-charge may decide and
         the result given there shall be. considered correct and authentic by the
         contractor. The contractor shall be given access to all operations and tests
         that may be carried out as aforesaid so that he satisfied himself regarding
         procedure and methods adopted.

39       LAYING P.C.C. SLABS:
39.1     Special care shall be taken while transporting P.C.C. Slabs from stock yard
         to work site and stacked near P.C.C. slabs either damaged or cracked or
         broken shall not be used for lining. Compacted canal slope shall be wetted
         and first layer of 12.5 mm. thick cement mortar (1:5) shall be applied, leveled,
         and compacted using wooden, steel or any approved screed board to form
         uniform surface. The second layer of 10 mm. thick with cement mortar (1:3)
         shall be applied when the first layer of mortar is used for one day. The surface
         of second layer of mortar shall be leveled and P.C.C. slabs are fixed in 6
         mm. thick cement mortar (1:3). The slabs shall be pressed gently so that the
         mortar squeezes thorough joints. These joints are neatly finished flush with
         top surface of the slab. The P.C.C. Slab lining shall be done from bottom to
         the top in a stretch not more than 10.Mts.length and vertical break joints shall


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TECHNICAL SPECIFICATION

         be ensured in P.C.C. Slabs. The lining surface shall be uniform and smooth.
         After completion of P.C.C. lining in a length of not less than 100 meters, the in
         situ-bed lining and top lug shall be laid in the next 100M. reach cast in situ
         cement concrete with a cement level of not less than 250 kgs/cum. The line
         surface shall be even true to the face smooth to give designed coefficient of
         rugosity.
                          Tolerance in alignment and grade

           a)     Departure from established + 20 mm on straight reaches
                  alignment

                                                  + 50 mm on curve or tangents

           b)     Departure from established + 20 mm on small canal
                  grade




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TECHNICAL SPECIFICATION

                              Annexure – 1
             NECESSITY AND TYPE OF DRAINAGE ARRANGEMENT

                                                                              GWT ABOVE CANAL
                              GWT BELOW CANAL BED LEVEL
                                                                                 BED LEVEL
                               CUTTING
      SUB-GRADE                                   FILLING REACHES               CUTTING REACHES
                               REACHES
          1.                                              3.                           4.
                                  2.
I. Discharge less than
0.3 cumec.
i) Free draining          --------              No drainage                 ------------
                                                arrangement is
                                                necessary
ii) Poorly draining       --------              No drainage                 ------------
                                                arrangement is
                                                necessary
iii) Impervious/rocky     --------              No drainage                 ------------
                                                arrangement is
                                                necessary
II. Discharge between
0.3 cumec to 3.0
cumecs
i) Free draining          -------- no drainage arrangement is necessary     Bed : Longitudinal drain
                          ----------                                        (LD) with pressure release
                                                                            valve (PRV) in pocket filter
                                                                            (PF) at 15m interval.
                                                                            Slope : PRV in PF at 15 m
                                                                            interval
ii) Poorly draining       -------- no drainage arrangement is necessary     Bed : LD with PRV in PF at
                          ----------                                        10m interval.
                                                                            Slope : PRV in PF at 10m
                                                                            interval
iii) Impervious/rocky     -------- no drainage arrangement is necessary     Bed : Sand filter and LD
                          ----------                                        with PRV in PF at 10m.
                                                                            interval.
                                                                            Slope : Sand filter from FSL
                                                                            extended upto Bed.
III. Discharge between
3.0 cumec to 15 cumecs
i) Free draining          -------- no drainage arrangement is necessary     Bed : LD with PRV in PF at
                          ----------                                        10m interval.
                                                                            Slope : PRV in PF at 10m
                                                                            interval.
ii) Poorly draining       Bed : LD with PRV     Bed : Sand filter with      Bed : LD with PRV in PF at
                          in PF at 15m          PRV in PF at 15m            10m interval.
                          interval.             interval.                   Slope : TD from FSL
                          Slope : TD from       Slope : (i) Cutting         connecting to LD at 10m
                          FSL connecting to     portions-sand filter from   interval.
                          LD in bed at 15m      FSL extending upto
                          interval.             bed.
                                                (ii) Filling portions :
                                                (a) Draining – No
                                                     arrangement
                                                (b) Poorly draining – TD
                                                     from FSL at 15m
                                                     interval.
iii) Impervious/Rocky     Bed : Sand filter     Same arrangement as         Bed : Sand filter and LD
                          and LD with PRV       indicated in III(ii)        with PRV in PF at 10m
                          in PF at 15m          column-3.                   interval.
                          interval.                                         Slope : Sand filter from FSL
                          Slope : Sand filter                               extended upto bed.
                          from FSL
                          extending upto
                          bed.
IV. Discharge above 15
cumecs :



                                                                                                   174
TECHNICAL SPECIFICATION

i) Free draining           -------- no drainage arrangement is necessary       Bed : Longitudinal pipe
                           ----------                                          drain (LPD) with PRV in
                                                                               outlet at 10m interval.
                                                                               Slope : Transverse drain
                                                                               (TD) from FSL connected to
                                                                               LPD at 10m interval.

ii) Poorly draining        Bed : LPD with        Bed : LPD with PRV in         Bed : LPD with PRV in
                           PRV in outlet at      outlet at 15m interval.       outlet at 10m interval.
                           15m interval.         Slope : TD from FSL           Slope : TD from FSL
                           Slope: TD from        connected to LPD at           connected to LPD at 10m
                           FSL connected to      15m interval.                 interval.
                           LPD at 15m
                           interval.
iii) Impervious/Rocky      Bed : Sand filter     Same arrangement as           Bed : Sand filter and LPD
                           and LPD with PRV      indicated in IV(ii)           with PRV in outlet at 10m
                           in outlet at 15m      column-3.                     interval.
                           interval.                                           Slope : Sand filter from FSL
                           Slope : Sand filter                                 extended upto bed.
                           from FSL
                           extending upto
                           bed.

Notes :

(i)       Incase canal is passing through bunded paddy field the operative rainy season water level may
          cause hydrostatic pressure to build up against the lining in canal slopes. Therefore, if the
          hydraulic gradient line with an assumed 6:1 slope from the field adjoining the canal cuts the
          canal side slope more than 30 cms above the canal bed, drainage arrangement applicable for
          WT above CBL shall be provided even though GWT may be below CBL.
(ii)      Highest ground water table (GWT) available in a year shall be considered for providing
          drainage behind lining.
(iii)     In case of GWT below CBL but perched ground water table above CBL, drainage arrangement
          as indicated in deep cutting for impervious/rocky subgrade shall be provided.
(iv)      PRV in slope shall be staggered with reference to bed.
(v)       Explanation of abbreviations: -
(i)       GWT      -        Ground Water Table.         (ii)     CBL      -        Canal bed level.

(iii)     PRV         -    Pressure Release Value. (iv)        PF          -        Pocket filter
(v)       LD          -    Longitudinal drain.     (vi)        TD          -        Transverse drain.

(vii)     LPD         -    Longitudinal Pipe Drain.   (viii)   FSL         -        Full Supply Level


2.0 Clearing Site :

          The area proposed for lining the canal as a whole shall have to be cleared of
          all objectionable material. Any waste material obtained from such site
          clearance shall be disposed off in a manner directed by the Engineer-in-
          Charge.

3.0       Trimming the Canal Section and Preparation of Sub-grade for concrete
          lining :-




3.1       General :

          (a) The provisions of this paragraph applies to the preparation of sub grade
              upon which concrete lining is to be placed.



                                                                                                        175
TECHNICAL SPECIFICATION

         (b) The work of trimming the canal section up to the underside of concrete
             lining and preparing sub grade for concrete lining includes excavation,
             preparing the base for lining shall be carried out by machine (trimmer) of
             adequate capacity to match with the paving machine used for lining with
             insertion of PVC strip immediately prior to laying of the lining but in no
             case the time interval should exceed 3 days in normal weather and 2 days
             in adverse weather conditions. Wherever, rock is over excavated the item
             of trimming and preparation of Sub grades includes, filling the over
             excavated portion with suitable semi previous material, watering,
             compaction and its trimming up to underside of the concrete lining. All
             along the canal alignment the raincuts on the banks shall be filled up with
             approved excavated material and shall be compacted adequately to
             required line and level. The material required for filling the over excavation
             in rock and raincuts if not available during excavation in soils to be done
             under this item shall be hauled from stockpiles and placed in position. The
             bed and side slopes shall be trimmed to the required section by using
             trimmer machine. The canal bed and slopes shall be dressed, watered
             and compacted by suitable rollers and slope compactors.

         (c) If at any point material has been excavated beyond the pay line required
             to receive the concrete lining the excess excavated shall be refilled in
             horizontal layers with selected material moistened. If required and
             compacted using rollers and slope compactors. Where placing and
             compacting bedding material is on a sloping foundation. The layer may be
             placed parallel to the surface of the foundation. If at any point the
             foundation material is disturbed or loosened during the excavation
             process or otherwise it shall be moistened, if required and thoroughly
             compacted by tamping, rolling or other approved methods to form firm
             foundation for placing the concrete lining.

         (d) Immediately prior to placing the first lift of bedding material, the surface of
             the excavation and embankment to receive the material shall be
             adequately wetted to a depth of 15 cm or to impermeable material
             whichever is less as approved by the Engineer-in-Charge.

         (e) After the canal prism has been shapped to a reasonable true and even
             surface as described above, bedding material shall be placed on
             adequately wet surface in layers of 15 cm maximum thickness to bring the
             bedding material to a height where it can be trimmed to form a true and
             even surface upon which the concrete for lining is to be placed. Each
             layer of bedding material shall be moistened and thoroughly compacted.

         (f) At the end panels of existing lining against which lining is to be placed
             under these specifications, all loose material shall be removed and all
             voids beneath the existing lining shall be refilled and thoroughly
             compacted.

         (g) Suitable material trimmed from the canal shall be used to complete canal
             embankment or to construct road embankment or for back fill around
             structures or to deposit bedding, material. Where material suitable fro
             bedding determined by the Engineer-in-Charge is encountered during
             trimming operations and can not be placed in one continuous operation,
             such material shall be stockpiled along the right-of way where designated
             by the Engineer-in-Charge.




                                                                                        176
TECHNICAL SPECIFICATION




3.2      Tolerances

         Excavated profile provides the final base for lining and tolerances i.e.
         departure from establishment alignment shall be as indicated.

                  +       20 mm on straight section.
                  +       50 mm on tangents.
                  +       100 mm on curves.

         Departure from established grade.

                  +       20 mm

         The above tolerance shall be negotiated gradually through smooth transition
         in a length of 50 m.

4.0      Cost in situ Concrete Lining :
4.1      General :
         The work shall conform to IS : 3873-1978. The concrete shall be of controlled
         grade with suitable admixtures of approved air entraining agents, using well
         graded aggregates with maximum size of aggregate of 40 mm. Ordinary
         Portland Cement or Portland Pozzolana Cement shall be used at the rate of
         221-75 Kg/m3 concrete. However due to change in design mix, if it becomes
         obligatory to use leaner/richer mix the Contractor shall comply the same
         without any extra cost. In case of leaner mix, the deptt. shall deduct the cost
         of cement from the bill at the base price of Rs. 2400/- (Rs. Two thousand four
         hundred only) per tonne of cement at worksite including handling etc. for short
         consumption of OPC/PPC. Design mix and actual cement level required shall
         be communicated from time to time by the Contractor in writing to the
         Engineer-in-Charge.

4.2      Batching :

         (a) The contractor shall provide such means and equipments as are required
             to accurately determine and control the relative amounts of the various
             materials including water, cement, admixture, sand and each specified
             size of coarse aggregate required for the concrete. Such means and the
             equipment and its operation shall be subject, at all times, to the approval
             of the Engineer-in-Charge. The quantity of cement, fly ash (if required),
             sand and each size of coarse aggregate entering each batch of concrete
             shall be determined by weighing and the quantity of water required shall
             be determined by volumetric measurement.

         (b) The measuring and test weighing equipment shall operate within the limit
             of accuracy specified. Standard weight and other auxiliary equipments
             required for checking their satisfactory performance shall be provided by
             the Contractor.

         (c) The equipment shall be capable of controlling the delivery of material for
             weighing or volumetric measurement so that combined in accuracies in
             feeding and measuring during normal operation do not exceed 1% for
             water and 3% for all aggregate. Periodical tests shall be made at least
             once in every two weeks in the case of equipments for measuring water,
             cement, and admixtures and at least once in every month in case of


                                                                                    177
TECHNICAL SPECIFICATION

             equipment measuring sand and coarse aggregate. However this shall not
             obviate any surprise checking and testing at any time as desired by the
             Engineer-in-Charge. Repairs, replacement, or adjustments of equipment
             shall be made as necessary in order to secure satisfactory performance.

         (d) The weighing equipment shall conform to the requirement of IS: 2722-
             1964 and the batching and mixing plant to the requirement of IS: 4925-
             1968.

4.3      Mixing :

         (a) Concrete shall be mixed in a mechanical mixer and shall be as a dense
             as a dense as possible plastic enough to consolidate well and stiff enough
             to stay in place on the slopes.

         (b) Mixing shall be continued until there is uniform distribution of the materials
             and the concrete is uniform in colour and consistency. The mixing shall be
             as shown in table 1 of IS : 457-1957 reproduced below :

      Capacity of Mixer                    Minimum time of mixing
                                Natural Aggregates Manufactured Aggregates

          3 m3 or larger              2 Minutes                  2 ½ Minutes

               2 m3                 1 ½ Minutes                    2 Minutes

         1 m3 or smaller            1 ¼ Minutes                  1 ½ Minutes


4.4      Consistency

         The quantity of water to be used in the concrete shall be determined from to
         time to time during of course of concreting work in order to secure concrete of
         proper consistency and also adjust for any variation in the moisture content or
         grading of the aggregates as they enter the mixer. Addition of water to
         compensate the stiffening of the concrete resulting from over mixing or
         objectionable drying before placing shall not be permitted. Uniformity in
         concrete consistency from batch to batch shall be required where concrete is
         laid from the bottom to the top of the slope the consistency shall be such that
         the concrete will just stay place on the slope A slump of 60mm to 70mm shall
         generally be allowed. For heavier longitudinally operating slip from machines,
         a slump of 50 mm shall be permitted. To have a close control of consistency
         and work ability of concrete. The slump of concrete shall not very more than
         20mm from the one specified above as it would otherwise interfere with the
         progress and quality of the work.

4.5      Transporting :

         (a) Concrete shall be handled from the place of mixing to the place of final
             depositing as rapidly as practicable by use of equipments such as transit
             mixers which will prevent initial setting, segregation or loss of any of the
             ingredients. It shall be transported and compacted in its final position
             within 30 minutes of its discharge from the mixer unless carried in
             property designed agitators operating continuously when this time shall be
             within 2 hours of the addition of cement to mix and within 30 minutes of its
             discharge from the agitator.


                                                                                       178
TECHNICAL SPECIFICATION



         (b) If segregation occurs during transport, the concrete shall be remixed
             before being placed, after observing the time requirements as above.

4.6      Placing and Compaction :

         (a) Concrete shall be placed only in the presence of a duly authorized
             representative of the Deptt. Concrete shall be placed and compacted
             before initial setting time and shall not be subsequently disturbed.
         (b) Placing of concrete shall not be started until all from work, installation of
             part to be embedded, if any, and preparation of surface upon which
             concrete is to be laid, have been completely inspected and than so
             directed by the Engineer-in-charge. All absorptive surface against which
             concrete is to be laid shall be moistened adequately so that moisture
             shall not be with drawn from freshly placed concrete. The surface,
             however shall be free from standing water and mud.
         (c) Concrete shall be deposited in all cases as neatly as practicable directly
             from mechanized paver of adequate capacity provided PVC strips if
             provided in its final position and shall not be caused to flow in manner to
             permit segregation. Excessive separation of the coarse aggregate
             caused by allowing concrete to fall freely from too great a height or at too
             great an angle from the vertical shall not be permitted and where such
             separation would otherwise occur the contractor shall provide suitable
             means to convey the concrete without allowing such separation.

4.7      Hand Placing :

         (a) Hand placing of the concrete shall not be permitted under any
             circumstances.

4.8      Mechanical Placing

         (a) For efficient placing and finishing of the concrete lining on slopes and in
             bed, concrete lining machines such as slip from paver or concrete paver
             finisher approved quality and design shall be used. Rated capacity of
             each lining machine and associated support equipment utilized under this
             contract shall place canal lining at an average sustained rate of
             advancement of not less than 10 meters per hours. This minimum rate
             shall be obtained fro paving operations on the side slope and on the
             bottom of the canal while also meeting the requirements for the lapsed
             time following trimming, consolidation of concrete thickness, tolerances,
             finishes, joints and other requirement specified herein. The equipment
             and operations for foundation trimming, sub grade preparation concrete
             production, concrete delivery, joint production, curing compound
             placement and other associated activities supporting the placement of the
             canal lining shall be matched with the lining equipment capability so as
             not to impede the specified placement rate of each lining operation. The
             overall equipment deployment shall be such as to ensure the completion
             of canal lining within schedule period specified in the contract.

         (b) Concrete when deposited shall unless other wise specified have a
             placement temperature not less than 4.5o C and not more than 32o C.

         (c) Concrete shall be deposited and spread on the bed and sides or the canal
             as indicated on the drawings. Concrete may be so laid as to facilitate
             placing, vibrating, finishing and curing operation. The side lining concrete


                                                                                      179
TECHNICAL SPECIFICATION

               on side of canals shall be screeded up the slope, while the concrete is
               being vibrated a head of the screed concrete required for keys as shown
               on the drawings shall be laid integrally along with the side lining.

         (d) Alternately, the Contractor can select to use longitudinally operating self
             aligning slip form machine with built in vibrators attached to the side forms
             so as to effectively compact and finish the slope and bed concrete.

         (e) The joints shall be formed by inserting PVC strips if provided in green
             concrete.

4.9      Finishing

         (a)      All exposed concrete surfaces shall be cleaned of impurities, lumps of
                  mortar or grout and unsightly stains. The finished surface shall be
                  even, smooth and free from pockets and equivalent to that obtainable
                  by effective use of a long handle steel trowel. Where the surface
                  produced by lining machine meet the specified requirement, no further
                  finishing operation will be required. Surface irregularities, when tested
                  with a straight edge of 1.5 meter length shall not exceed 6 mm in
                  canal bed for bottom slab and 12mm in that laid on side slopes.

         (b)      Concrete of canal lining on slopes & bed including key at the top and
                  curved portion at the bottom the slope of canal shall be cured with
                  liquid membrane forming while pigmented curing compound which
                  shall form water retaining surface to achieve the desired effect of
                  water curing of 28 days. The curing compound shall be white
                  pigmented of approved quality conforming to ASIM-C-309-81.

         (c)      Repairs to concrete surface and additions where required shall be
                  made by cutting regular openings into the concrete and placing fresh
                  concrete to the required lines chipped openings shall be sharp and
                  shall not be less than 75 mm in depth.

4.10     Curing

4.10.1 General

         The concrete lining on slopes including curvatures portion at junction of slope
         and bed lining shall be cured with liquid membrane forming curing compound
         in accordance with specifications given in para 4.10.2. The concrete lining in
         canal bed shall be cured with water in accordance with the specifications
         given in para 4.10.3. If water curing of lining in the canal bed is not carried out
         to the satisfaction of the Engineer-in-Charge as per specifications. The
         Contractor shall be directed to switch over to liquid membrane forming curing
         compound for curing for which no extra payment shall be made to the
         Contractor.

         All equipment, material, etc. needed for curing and protection of concrete
         shall be at hand and ready for installing before actual concreting begins.
         Detailed plans, methods and procedures whereby the various phases of
         curing and protection shall be firmly established, shall be settled and got
         approved in writing from the Engineer-in-Charge sufficiently in advance of the
         actual concreting. The equipment and method proposed to be utilized shall
         provide for adequate control and avoid interruption or damage to the work of
         other agencies.


                                                                                       180
TECHNICAL SPECIFICATION




4.10.2 Membrane Curing

(a)      These specifications cover curing of concrete using membrane forming
         compound to retard the loss of water during the early hardening period and to
         reduce the temperature rise in concrete exposed to radiation from the sun.
         This compound shall be suitable for use as curing media for fresh concrete
         and for further curing of concrete after removal of forms or after initial moist
         curing.
(b)      White pigmented compound (Type 2) shall consist of finely divided white
         pigments and vehicle solids, ready mixed for immediate use without
         alteration. The compound shall present a uniform white appearance when
         applied uniformly to a fresh concrete surface at a specified rate of application.
         It shall be of such consistency that it can be readily applied by spraying to
         provide uniform coating at temperatures above 4oC. If two coat are to be
         applied then it should be applied at an interval of approximately one hour.
         They shall adhere to freshly placed concrete that has stiffened or sufficient to
         resist marking during the application and to damp hardened concrete and
         shall form a continuous film when applied at the specified rate of application.
         When dry, the covering shall be continuous, fixible and without visible breaks
         or pin holes and shall remain as unbroken film at least 28 days after
         application. It shall not react deleteriously with the concrete.
(c)      The compound shall meet with the requirement of water retention test as per
         ASTM designation C-156-80.The loss of water in this test shall be restricted
         too not more than 0.55 Kg/m2 of exposed surface in 72 hours.
(d)      The white pigmented compound type - 2, when tested as specified in
         accordance with method E-97 of ASTM shall exhibit a day light reflectance of
         not less than 60% of that of magnesium oxide.
(e)      It shall fulfill the requirement of drying time when tested in accordance with
         ASTM C-309-81. The compound applied shall be dry to touch in not more
         than 4 hours. After 12 hours it shall neither be tacky nor tack off (peel off)
         concrete when walked upon nor it shall impart a slippery surface.
(f)      Testing ;
         (i)      The liquid membrane forming curing compound to be brought in the
                  manufactures original clear containers. Each container shall be legibly
                  marked with the name of the manufacturer, the trade name of the
                  compound, the type of compound and class of vehicle, solids, the
                  nominal percentage of volatile material.
         (ii)     The surface of concrete finished against form shall be smooth and
                  free from projections, honeycombing and other objectionable defects.
                  Immediately on removal of forms all unsightly ridges or dips shall be
                  removed and undesirable local bulging on exposed surfaces shall be
                  remedied by tooling and rubbing.


                          Quantity of concrete m3            Number of Samples
                                                                     1
                                  1 to 5
                                                                       2
                                  6 to 15
                                                                       3
                                 16 to 30
                                                                       4
                                 31 to 50


                                                                                      181
TECHNICAL SPECIFICATION

                                                        4 plus one additional sample for
                            51 and above                 each additional 50 m3 or part
                                                                    thereof.

                  Note : At least one sample shall be taken during each shift.

5.3      Test Specimen

         Three test specimen shall be made from each sample for testing at 28 days.
         Additional cubes may be required for various purposes, such as to determine
         the strength of concrete at 7 days or at the time of striking formwork or to
         determine the duration of curing on to check the testing cube cured by the
         accelerated methods as described in IS: 9018-1978. The specimen shall be
         tested as described in IS: 516-1959.

5.4      Test strength of samples

         (a)      The test strength of the sample shall be the average of three
                  specimen. Individual variation shall not be more than 15% of the
                  average.

         (b)      Contractor shall provide necessary unskilled labour and facilities for
                  transport for collection of samples, cores etc. and shall remain present
                  at the time when the samples, cores etc are taken. Testing shall be
                  carried out at the testing laboratories setup at the site or at any other
                  laboratory that the Engineer-in-Charge may decide upon and the
                  results given there by shall be considered as correct and authentic
                  and acceptable to the contractor. The contractor shall be given access
                  to all operation and tests that may be carried out as aforesaid. All
                  testing charges are to borne by the SSNNL.

5.5      Acceptance Criteria

         (a)      The average strength of the group of cubes cast for each days shall
                  not be less than the specified cubes strength for the work. About 20%
                  of the cubes cast for each day may have values less than the
                  specified strength provided the lowest value is not less than 85% of
                  the specified strength.

         (b)      In case the concrete does not conform to the accepted criteria for
                  strength as specified above, the Engineer-in-Charge reserves the right
                  to reject the work or accept the same at a reduced rate derived from
                  tendered rate and as approved by him. Whenever necessary for the
                  purpose of obtaining economy, workability, density, impermeability,
                  durability or strength on account of variation in the quality and
                  gradation of aggregates or other materials the Engineer-in-Charge, in
                  consultation with Laboratory Division, shall after testing make
                  necessary changes in the proportion of mix. Contractor shall have to
                  effect these changes and will not be entitled to any compensation on
                  account of such changes.

6.0      Joints

         In canal lining construction joints shall be provided to accommodate
         expansion and contraction of the concrete or to provide continuity between
         the breaks in construction work. Joint shall be provided as shown on the


                                                                                       182
TECHNICAL SPECIFICATION

         drawings or as directed by Engineer-in-Charge. Normally in plain cement
         concrete lining joints shall be provided at 4 meters center, where as incase of
         RCC lining joints shall be provided in longitudinal direction only at 8 meters
         center to center. The detailed specification for PVC joints in plain cement
         concrete lining shall be as per para 12.0. The reinforcement shall discontinue
         at joint.



7.0      Tolerance

         (a)      The intent of this paragraph is to establish tolerance that are
                  consistent with modern construction practice and yet be governed by
                  the effect that permissible deviations will have upon the structural
                  action or operational function of the structure. Deviations from the
                  establish lines, grades and dimensions shall be permitted to the extent
                  set fourth herein below provided that the Department reserves the
                  right to diminish the tolerance set forth herein if such tolerance impairs
                  the structural action or operational function of the lining.

         (b)      Tolerance for lining shall be permitted within the following limits
                  :-

(i) Departure from established alignment.       20mm on straight reaches
                                                50mm on tangents.

(ii) Departure from established grade           100mm on curves
                                                20mm on straight reaches.

(iii) Variation in concrete lining thickness.   10% of lining thickness provided average
                                                thickness of each day’s placement is not
                                                less than specified thickness.

         Any departure from alignment or grade shall be uniform and no corrections in
         alignment be made in less than 50 meter. No over run in concrete quantity
         shall be paid to the contractors.

8.0      Dewatering

         In canal reaches where subsoil water is met with above, the canal bed level
         dewatering shall be resorted to and continued during preparation of sub
         grades providing under drainage arrangement and placing of concrete for
         lining till such period the concrete attains necessary strength. No separate
         payment shall be made for dewatering operations, as the same is deemed to
         have been included in rate related item in schedule “G”.

10.0     Safety Ladders

10.1     General :

         The contractor shall construct the concrete steps along the canal near the
         structures. Steps shall be constructed in concrete M-10 grade as shown in the
         drawing or as directed by the Engineer-in-Charge.

11.0     Pressure Relief Values:



                                                                                        183
TECHNICAL SPECIFICATION

11.1     General

         (a) Vertical non metallic (PVC) pressure relief valves of 50mm dia and
             150mm dia as shown on the drawing shall be provided and fixed in
             position. The item include excavating pits and refilling the same with filter
             materials, where necessary as per drawing or as directed by the
             Engineer-in-Charge.

         (b) The vertical pressure relief valve shall be procured by the Contractor at
             his own cost as per requirements. The valves shall be procured only after
             the make is got approved. These valves shall be fixed in bed as well as in
             slopes as per the drawings supplied by the deptt. or as per the
             instructions of the Engineer-in-Charge. Filter material to be used shall be
             of approved quality of sand gravel in required gradation. Graded filter as
             shown on the relevant drawings shall be carefully placed and compacted
             to form an even bedding upto the elevation of bottom of canal lining. Tar
             paper or any other suitable material, approved by the Engineer-in-Charge
             shall be placed over the entire surface of the gravel fill to prevent water
             from concrete entering the fill. The under drainage arrangement shall be
             is conform it with IS: 4558-1983 in general.

         (c) As an alternative to graded filter around PRV, geo-fabric of approved
             quality and design shall be used without any extra cost to the Deptt.

12.0     Insertion of PVC Crank Inducing Joints :

12.1     (a)      The transverse and longitudinal PVC (Poyvinyl Chloride) strips shall
         be provided with the shapes conforming to dimension shown on the drawing
         and off white in colour. The finished PVC strips shall be extruded from virgin
         pigmented, plasticized polyvinyl chloride (PVC). The PVC strips shall be
         dense, homogeneous, free from holes and other imperfections. The cross
         section of the PVC strips shall be uniform along its length and thickness shall
         be symmetrical transversely. Tolerance for dimensions in overall length and
         width shall be 5% and in thickness 10%. The finished PVC strips shall meet
         the following requirements.

         No.              Characteristic                           Values
         1.     Tensile strength                       Kg/cm2       116        Minimum
         2.     Ultimate Elongation                      %          300        Minimum
         3.     Tear Resistance                        Kg/cm2        49        Minimum
         4.     Stiffness if flexure                   Kg/cm2       24.6       Minimum
         5.     Accelerated extraction

                     (a) Tensile Strenght              Kg/cm2        105       Minimum
                     (b) Ultimate elongation             %           250       Minimum

                Effect of alkali at 7 days
                    (a) weight increase
                    (b) weight decrease                  %           0.10      Maximum
                    (c) Hardness change point            +5          0.10      Maximum

         6.     Effect of alkali at 28 days
                    (a) weight increase                  %           0.4       Maximum
                    (b) weight decrease                  %           0.3       Maximum
                    (c) Dimension                        %           +1        Maximum



                                                                                      184
TECHNICAL SPECIFICATION

                  Weight of PVC strip shall be a minimum of 460 g/m for the longitudinal
                  strip and a minimum of 420 g/m for the transverse strip.

         (b)      The above determination shall be made in accordance with the
                  specifications of Central Water Commission, Govt. of India in vogue.
                  The surface finish of PVC strips shall be mat finish, and off white in
                  colour.

         (c)      Contractor shall arrange for getting the finished PVC strips tested in
                  recognized testing Government Test Houses. The Contractor shall
                  furnish test samples of PVC strips in 30 cm length reel and free of cost
                  and also shall bear testing cost. Each sample shall be marked with the
                  number of the reel from which sample is obtained and with certification
                  that the samples are from the reels to be furnished.

         (d)      It is mandatory for the manufacturer of the PVC strips, from whom the
                  contractors procure PVC strips, to have a full-fledged testing
                  laboratory in the factory to enable pre-despatch testing of the
                  products, as in the event of laboratory test reports being received after
                  a few weeks, showing substandard values. It would not be possible to
                  remove the material embedded in concrete. Test reports from
                  Government test houses shall also be binding on the manufacturer
                  based on sample drawn by the Engineer-in-Charge and sent for
                  testing to Government test house, from consignments received at site.
                  The Contractor will get the sample of PVC strip approved by the
                  Engineer-in-Charge. He will furnish the name of manufacturer, the
                  detail of the in house testing arrangements with the manufacturer and
                  will also furnish a test report from the inhouse testing facilities along
                  with the sample.

12.2              (a)      The PVC strips shall be inserted in the concrete lining when
                  concrete is plastic. The longitudinal PVC strip shall be inserted before
                  the transverse PVC strips is inserted. The PVC strips at edges shall
                  be placed in position fixed with longitudinal channels by clips or such
                  other arrangement prior to lying of concrete. The PVC for crack
                  inducing joints shall be inserted in position in concrete lining as shown
                  in the drawing. The insertion of the longitudinal and / or transverse
                  PVC for crack inducing joints at the predetermined locations of joints
                  requires special attention to ensure proper location (depth is
                  especially important), plumb installation and consolidated concrete
                  around the PVC for crack inducing joint. The longitudinal PVC strips
                  including cellular upper fin. The inspection fin shown on the plate shall
                  be comparatively thin and shall remain above the top surface of lining.
                  It is important that top of the upper fin be at or near the concrete
                  surface. The manner of installation shall include mechanical vibration
                  that produces thorough consolidation of the concrete around the
                  cracks inducing joint and provides a continuous contact between the
                  concrete and all surfaces of the cracks inducing joint. The longitudinal
                  crack inducing joint shall be fed into the fresh concrete from reels
                  mounted in front of the paver through guides and tension relises so
                  placed as to ensure proper depth and orientation of the crack inducing
                  joint, installation of PVC for transverse crack inducing joint shall be
                  made by suitable joint inserter contrivance capable to insert into
                  freshly placed concrete lining.




                                                                                       185
TECHNICAL SPECIFICATION

    (b)         At intersections between longitudinal and transverse joint containing PVC
                strips, the top vertical member of the PVC of the longitudinal crack
                inducing joints, shall be cut or plucked and removed for 10 to 15 cm in
                width without putting the PVC from the concrete lining and transverse
                crack inducing joint shall be placed within the notch so formed.
                Depression of the PVC of the longitudinal cracks inducing joint from the
                concrete lining and transverse crack inducing joint shall be placed within
                the notch so formed. Depression of the PVC of the longitudinal cracks
                inducing joint below the specified positions in the concrete will be
                permitted at intersection only to the extent necessary to place the PVC of
                the transverse crack inducing joint to the specified depth. However,
                tolerances and concrete consolidation requirements of the preceding
                paragraph shall apply at intersections.


          (a)         The manner of making the intersection shall produce reasonably close
                      fit between transverse and longitudinal crack including joints and
                      provide a nearly continuous weekend plane normal to the lining
                      surface in both direction through the intersection.
13.0      Strip drain and under drainage arrangements
          13.1        General
                (a)      Excavation of strip drains longitudinal and transverse drains shall
                         be done to the correct line grades and sections as shown in the
                         drawings. The excavated material shall be disposed off as per
                         instructions of the Engineer-in-Charge.
                (b)      Open jointed stone ware pipe shall be placed in position in the
                         longitudinal and transverse drains and connected to pressure relief
                         valve chambers (kundies) as per layout shown on the relevant
                         drawing.
                (c)      Graded filter shall be provided as shown on the drawing,
                         compacted to form an even bedding upto the elevation of the
                         bottom of canal lining. Tar paper or any other suitable materials
                         approved by the Engineer-in-Charge shall be placed over the
                         entire surface of the filter to prevent water from concrete entering
                         the filter.




                                                                                         186
TECHNICAL SPECIFICATION

                           CHAPTER – 6 MORTARS
6.1 REFERENCES :

       IS: 269-1989        - OrdinaryPortland cement, 33 Grade (fourth revision).
       IS: 455-1976        - Portland slag cement (third revision) (with
                             mendments 1to6).
       IS: 456-1978        - Plain and Reinforced concrete (third revision).
       IS: 457-1957        - General construction of Plain and Reinforced
                             concrete for dams and other massive structures.
       IS: 460(Pt.I&II)    - Test sieves (third revision).
              -1985
       IS: 712-1984        - Building Limes (second revision).
       IS: 1290-1973       - Mineral G ypsum (second revision).
       IS: 1344-1981       - Calcinated clay Pozzolana (second revision) (with
                             amendments 1to6).
       IS: 1489-1976       - Portland Pozzolana cement (second revision).
       IS: 1514-1959       - Methods of sampling and test for quick lime and hydrated
                             lime (Reaffirmed 1978).
       IS: 1542-1977       - Sand for plaster (first revision) (Reaffirmed 1987).
       IS: 1635-1975       - Field slaking of building Lime and preparation of putty (first
                             revision).
       IS: 1727-1967       - Methods of test for pozzolanic materials (first
                             revision).
       IS: 2116-1980       - Sand for masonry mortar (first revision) (reaffirmed
               1987).
       IS: 2250-1981       - Preparation and use of masonry mortar                    (first
                             revision).
       IS: 2386 (Pt.I to   - Methods of test for aggregates for concrete.
             VIII)-1963
       IS: 3466-1988       - Masonry cement (second revision).
       IS: 4082-1977       - Stacking and storage of construction material at site (first
                             revision).
       IS: 4098-1983       - Lime Pozzolana mixture (first revision)
                             W ith mendment No.1).
       IS: 5512-1969       - Flow table for use in tests of hydraulic cement
                             and pozzolanic meterials.
       IS: 6508-1988       - Glossary of terms relating to building lime (first
                             revision).
       IS: 6932(Pt.1 to    - Methods of test for building limes.
           10) - 1973
       IS: 6932 (Pt.11)    - Methods of test for building limes.
            - 1984
       IS: 7969-1975       - Handling   and    storage     of  building  materials
                             (Reaffirmed 1987).
       IS: 8041-1978       - Rapid hardening Portland cement (first revision) (with
                             Amendment Nos. 1to3).
       IS: 9103-1979       - Admixtures for concrete.
                           - Engineer-in-Chief, Irrigation Department Publication
                            No.21."Central      Public      W orks     Department"
                           Specification of 1977.Specifications 77 of " National
                           Building Organisation".




                                                                                       187
TECHNICAL SPECIFICATION




Volume I –Sec..III             Specifications For Irrigation Projects Nov. 1991   6/2




6.2 TERMINOLOGY :
      Admixture - A Material other than water, aggregates, and hydraulic
cement, used as an ingredient of concrete or mortar and added to the
batch immediately before or during its mixing to modify one or more of the
properties of concrete in the plastic or hardened state.
      Air-Entraining Admixture - An admixture for concrete or mortar
which causes air to be incorporated in the form of minute bubbles in the
concrete or mortar during mixing, usually to increase workability and
resistance to freezing and thawing and disruptive action of deicing salts.
      Composite Mortar - A mortar containing cement and lime in
addition to other ingredients.
      Consistency - The working consistency of a mortar or plastering
mix as judged by the working from its behaviour during application. Its
assessment includes characteristics, such as initial fluidity, water
retentivity, etc.
       Granulated Slag - Slag in granulated form is used for the
manufacture of hydraulic cement. Slag is a non -metallic product
consisting, essentially of glass containing silicat es of lime and other
bases, in the case of blast furnace slag which is developed
simultaneously with iron and blast furnace or electric pig iron furnace.
Granulated slag is obtained by further processing a molten slag by rapidly
chilling or quenching it with water or steam and air.
      Hardening - The physic-chemical changes observed in a mortar
due to the effect of one or more of the following phenomena: -
           (a)       Absorption of carbon,
           (b)       Recrystallization, and
           (c)       Chemical reaction.
      Lime - A general term which includes the various chemical and
physical forms of quick lime, and hydraulic lime commonly obtained by
calcination or calcination and hydration from one or other calcarious
materials.
      Building Lime - A lime whose chemical and physical
characteristics and methods of processing make it suitable for
construction purposes, also known as “Construction lime”.
       Eminently Hydraulic Lime - Lime containing some quantities of
silica and alumina (and/or iron oxide) which are in chemical combination
with some of the calcium oxide content. This gives a putty or mortar which
has the property of setting and hardening under water.
      Fat Lime - Connotes a pure non-hydraulic lime. It may be in quick
hydrated or putty form.
       Hydrated Lime - A dry powder obtained by treating quick lime with
water enough to satisfy its chemical affinity for water under the condition
of its hydration.


                                                                                  188
TECHNICAL SPECIFICATION

      Hydrated Lime - Containing small quantities of silica and clumina
(with or without iron Oxide) which are in chemical combination with some
of the calcium oxide content giving a putty or mortar which has the
property of setting and hardening under water.
     Kankar Lime - The calcinate of Kankar. It may be hydraulic or
semi-hydraulic in nature. Kankar is the impure earthy stone rich in
concretious and nodules of calcium carbonate.
      Lime Putty - A wet plastic paste consisting of hydrated lime and
free water.


     Lime Slurry - A suspension of hydrated lime in considerable
amount of free water, with a consistency similar to cream.
Volume I –Sec..III        Specifications For Irrigation Projects Nov. 1991       6/3




      Milk of Lime - A suspension of lime in a large amount of water with a
consistenc y similar to milk.


       Megnesium Lime - Lime obtained from magnesium and dolomitic lime
stones or dolo stones which may contain more than 5 percent magnesium oxide
(ignited basis).


       Semi-hydraulic Lime - LIme containing small quantities of silica (with or
without iron oxide) which are in chemic al combination with some of the calcium
oxide content, and therefore, shows the property of setting and hardening under
water. This is intermediate in composition between eminently hydraulic and fat
limes.
        Slaking - Slaking usually means addition of the re quisite amount of water to
quick lime so as to form dry slaked lime, putty or slurry.


      Unslaked Lime (Quick lime) - A calcined material, the major part of
which is calcium oxide or calcium oxide in natural association with a lesser
amount of magnesium oxide, capable of slaking with water.


       Popping and Pitting - A type of unsoundness caused by particles of
unhydrated or incompletely hydrated lime which hydrates and expands at some
period subsequent to actual use. It manifests itself in the form of craters o r
blisters on plaster surfaces.


       Portland Clinker - Clinker consisting mostly of fusion - a predetermined
and homogeneous mixture of materials principally containing lime (Cao) and
silica (SiO 2 ) with a smaller proportion of alumina (Al 2 O 3 ) and iron oxide
(Fe 2 O 3 ).

       Portland Slag Cement - An intimately interground mixture of portland
cement clinker and granulated slag with addition of gypsum and permitted
additives or an intimate and uniform blend of portland cement and finely ground
granulated slag.




                                                                                 189
TECHNICAL SPECIFICATION

      Pozzolana - An essential silicious material which, while in itself
possessing no cementitious properties will, in finely divided form and in the
presence of water, react with calcium hydroxide at ordinary temperature to form
componuds possessing cementitio us properties.


       Calcined Clay Pozzolana - The calcined clay pozzolana is a reactive
pozzolanic material manufactured under controlled conditions by calcination of
clay at suitable temperature and grinding the resulting product to the required
fineness. This material can be used for manufacture of portland pozzolana
cement for blending with hydrated lime to produce ready to use lime pozzolana
mixture, and for part replacement of cement in unblended cement mortar and
concrete and for use as an admixture.


         Sand - A fine aggregate which iseither natural sand or crushed gravel
sand.
       Crushed Gravel Sand - Fine aggregates produced by crushing natural
gravel.


Crushed Stone Sand - Fine aggregates produced by crushing hard stone.


       Natural Sand - Fine aggregates resulting from the natural disintigration of rock and
which have been deposited by streams or glacial agencies.


        Water Retentivity - The ability of mortars to retain water against suction and
evaporation in general. It is indirectly a measure of the workability of mortars. It is measured
by the flow of mortar when tested on a standard flow table before and after application of a
specified suction.
Volume I –Sec..III            Specifications For Irrigation Projects Nov. 1991              6/4



6.3 MATERIALS :

      6.3.1 Cement :
      6.3.1.1 General - Unless otherwise specified Cement shall conform to
any of the Indian Standards, IS:269 -1989, IS: 455-1976, IS: 1489-1976,
IS:3466-1988, IS: 8041-1978, and IS:8112-1976 (amended from time to time).

     6.3.1.2 Stacking and Storage - As far as practicable, no consignment of
cement shall be received and transpor ted during the monsoon period.

       Cement shall be stored in dry and water proof sheds and on a platform
raised about 20 cm above ground level, and about 30 cm clear off the walls.
Cement bags shall be stacked in such a manner as to facilitate their removal
and use in the order in which they are received. W hen removing bags for use,
apply the “First in First out “ rule, that is take the oldest cement out first. For
this purpose each consignment as it comes in, shall be stacked separately and
playcard bearing the date of arrival shall be pinned into the pile. Each
consignment of cement shall also be stacked separately therein to permit eas y
access for inspection and facilitate removal. Cement bags shall not be stacked
more than 12 bags high to avoid lumping up u nder pressure.

       Cement shall be stored at the work site in such a manner as to prevent
deterioration due to moisture. The number of bags shall be kept to a minimum
preferably just sufficient for the day’s consumption. This manner of temporary
storage shall not be adopted in wet weather.



                                                                                           190
TECHNICAL SPECIFICATION

      Handling and storage facilities shall be such that no cement is stored
before use for more than 120 days, counted from the date of despatch by the
manufacturer. Cement stored beyond 120 days but not exceeding 180 days,
shall be tested and rejected if found defective in any way. Cement stored
beyond 120 days shall not be used for dams and that beyond 180 days shall not
be used for structural members and hydraulic stuctures.

         6.3.2 Building Lime - Lime shall conform to IS: 712-1984.

         6.3.2.1 Classification - Building lime shall be classified as follows: -

          Class-A Eminently hydraulic lime used for structural purposes.

          Class-B Semi-hydraulic lime used for masonry mortars, lime concrete and
                  plaster undercoat.

          Class-C Fat lime used for finishing coat in plastering, white - washing,
                 composite mortars, etc. and with addition of pozzolanic materials
                 for masonr y mortar.

          Class-D Magnesium/Dolomitic lime used for finishing coat in plastering,
                 whitewashing, etc.

          Class-E Kankar lime u sed for masonry mortars.

          Class-F Siliceous dolomitic lime used for under coat & finishing coat of
                  plaster.

          Note 1-         Lime shall be available either in hydrated or quick form,
                     except that of Class A and Class E which shall be supplied in
                     hydrated form.

          Note 2-         Applications indicated are only suggestive.

      6.3.2.2 Chemical requirements of building lime shall be as given in Table 1 of
IS:712-1984.
Volume I –Sec..III            Specifications For Irrigation Projects Nov. 1991      6/5



       6.3.2.3 Physical requirements of building lime shall be as given in Table
2 of IS : 712-1984.
      6.3.2.4 Supply and Storage - The lime packages shall bear the type and
class of lime, brand, name of manufacturer, da te of manufacture and the net
weight; in case of quick lime the slaking temperature shall also be indicated.
       6.3.2.4.1 Hydrated Lime - Hydrated lime shall be supplied in suitable
containers such as jute bags lined with polythene of HDPE woven bags lined
with polythene or craft paper bags. Preferably containing 50 Kg of lime. It shall
be stored in a building to protect the lime from dampness and to minimise ware -
house deterioration.
      6.3.2.4.2 Quick Lime Before Slaking - Quick lime shall be supplied in
containers like metal container or similar suitable containers preferably
containing 50 Kg of lime. Quick lime deteriorates rapidly on exposure by taking
up moisture and carbon dioxide from atmosphere.
      It shall be slaked as soon as possible before deteriorati on sets in. If
unavoidable, it may be stored in compact heaps having only the minimum of
exposed area. The heaps shall be stored on a suitable platform and covered to
avoid direct contact with rain or being blown away by wind. In case quick lime is
stored in a covered shed, a minimum space of 300 mm shall be provided
alround the heaps to avoid bulging of walls. Unslaked lime shall be stored in a



                                                                                    191
TECHNICAL SPECIFICATION

place inaccessible to water and because of the fire hazard shall be segregated
from the combustible materials.

         6.3.2.4.3 Dry Slaked Lime - If the lime is to be used within a few days it
may be stored on a platform suitably covered for protection from rain and wind.
If it is required to be stored for a longer period not exceeding 2 months it may
be kept in a dr y and closed godown.

       6.3.2.4.4 Putty - The lime putty shall be stored under water. The putty of
class C and D lime may be stored upto 15 days and putty of class B and E lime
shall be used as soon as after preparation.

         6.3.2.5 Slaking Quick Lime and Preparation of Putty:

        6.3.2.5.1 Preliminary Cleaning - The slaking receptacle or platform shall
first be cleaned of all unslaked stones of lime and other materials left over from
previous slaking.
        6.3.2.5.2 Slaking Procedure - The slaking shall be done either in tan ks
by adding ‘lime to water’ or on platform by adding ‘water to lime’ as described
below :-
        Tank slaking - This method directly results in lime putty and is thus
suitable when the end product is required in this form. The tank shall be water
tight and large enough to permit stirring of the mix. Its sides and bottom shall be
lined with a material which is not at tacked by lime. Brick lining is recommended.
For providing continous slaking operation, two tanks may be used, one 40 cm
deep at a lower level above ground and the other about 74 cm deep at a lower
level below ground. The slaking of the quick lime is done continously in the
higher tank and resultant milk of lime allowed to flow, through a sieve if desired,
into the lower tank where it will settle and mature into putty. To obtain a
continous supply of putty, two tanks instead of one may be provided at the lo wer
level and used alternately so that when putty is being used from one, fresh putty
may be formed in the other. The tank shall be filled with water to a depth of 25
to 30 cm. Quick lime shall be gradually added to it so as to cover the entire
bottom of the tank to about half the depth of water. W hile quick lime is being
added to water it shall be constantly stirred so as to break up the lumps and aid
the slaking process with minimum cooling of the mix. No part of the lime shall
be allowed to get exposed above water. As lime slakes with the evolution of
heat, the temperature of water will begin to increase. W hen a temperature near
boiling point is reached, addition of lime and water shall be made


Volume I –Sec..III        Specifications For Irrigation Projects Nov. 1991      6/6



in small quantites with constant stirring so as to maintain the required
temperature. The operation shall be continuous until the requisite quantity of
lime has been slaked. After the slaking is apparently over, the stirring shall be
continued for some more time to ensure that all the lime has been fully slaked.
The lime shall be allowed to stand undisturbed in the tank, where only one tank
is used, or run into a lower tank whe re one is provided, and allowed to mature
into lime putty. The maturing period shall not be less than 3 days in the case of
Class C and D lime and not more the 2 days in case of class B and E lime.


       Platform Slaking - This method provides dry slaked lime which can be
used as it is or after converting it into putty (See para 6.3.2.5.3 below). Quick
lime is spread in 15 cm thick layer on a water tight masonry platform and water
sprinkled over it in small quantities thro ugh a rose cane or with a hose pipe until
the lime disintegrates into fine powder. Care shall be taken to see that only the
minimum quantity of water required for complete and uniform slaking is added. It
shall be periodically turned over. Slaking shall be allowed to continue further by




                                                                                192
TECHNICAL SPECIFICATION

itself for a period of atleast 24 hours. The slaked lime shall then be screened
through 250 micron IS : Sieve.


       6.3.2.5.3 Preparation of Putty - The putty shall be obtained by adding
dry slaked lime to water and stirring to the consistenc y of thick cream, and
allowing it to stand and mature for a period which shall not be less than 16
hours in the case of Class C and D limes, and not more than 12 hours in the
case of Class B and E before using it as slaked lime.


         6.3.3 Calcined Clay Pozzolana (SURKHI).


      The calcined clay pozzolana is a reactive pozzolanic material, shall conform to
IS:1344-1981.


       6.3.3.1 Calcined clay pozzolana shall conform to the physical
requirements given in Table 1 below when tested in accordance with IS: 1727 -
1967.


      Notwithstanding the strength requirements specified in Table 1, mixes in
which calcined clay is incorporated shall sho w a progressive increase in
strength.


                                 TABLE I - Physical Requirements


S.No.                CHARACTERISTIC                                            REQUIREMENT
                                                                         Grade I         Grade II
(1)                        (2)                                              (3)                 (4)


(i)     Fineness - Specific surface in m 2/Kg by Blaine's                    320             250
        permeability method, Min.


(ii)    Lime reactivity - Average compressive strength in                    40              3.0

        N/mm2, Min.


(iii)   Compressive strength at 28 days, Min. (Applicable in   Not less than 80 percent
        of the case of pozzolana to be used for manufacture of strength              of
        corresponding plain Portland pozzolana cement only).   cement mortar cubes.


(iv)    Drying shrinkage, Max.                                               0.15        0.10


6.3.3.2 Supply and Storage - The calcined clay pozzolana may be supplied in
bags (jute, jute laminated, multiply paper or polythelene lined) bearing the
manufacturer’s name or registered trade marks, and the net mass of each bag
shall be 50 kg. The permissible tolerance on the mass of calcined clay


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                                                                                             193
TECHNICAL SPECIFICATION



pozzolana shall be protected from rain and dampness and shall be stored in
such manner as to permit eas y access for proper inspection and identification of
each consignment. It shall be stored at site on a ha rd dry and level patch of
ground. If such a surface is not available , a platform of planks or old corrugated
iron sheets, or a floor of bricks, or a thin layer of lean concrete shall be made
so as to prevent the admixture of clay, dust, vegetable and othe r foreign matter.


6.3.4 Sand :


6.3.4.1 Quality of Sand :


       6.3.4.1.1 General - The sand shall consist of natural sand, crushed stone
sand or crushed gravel sand or a combination of any of these. The sand shall be
hard, durable, clean and free from adherent coatings and organic matter and
shall not contain the amount of clay, silt and fine dust more than the limits
specified under para 6.3.4.1.3 below.


       6.3.4.1.2 Deleterious Material - The sand shall not contain any harmful
impurities, such as Iron pyrites, alkalies, salts, coal or other organic impurities,
mica, shale or similar laminated materials, soft fragments, sea shells in such
form or in such quantities as to affect adversely the hardening, strength or
durability of the mortar, or the appeara nce in case of plaster or applied
decoration or to cause corrosion of metal lathing or the other metal in contact
with the plaster.


         6.3.4.1.3 Limits of Deleterious Materials and other Impurities - Unless found
satisfactory as a result of further tests as may be specified by the Engineer-in-charge, or
unless evidence of such performance is offered which is satisfactory to him. The maximum
quantities of clay, fine silt, fine dust and organic impurities in the natural and crushed stone
sand shall not exceed the following limits,when determined in accordance with IS:2386 (Part
ll) - 1963.
          (a)    Clay, fine silt and fine dust not more than 5% by mass when
                 determined in    accordance with the procedure at Appendix -l;


          (b)    Organic impurities when determined in acc ordance with IS:
                 2386(Part ll) 1963. Colour of the liquid shall be lighter than that
                 indicated by the standard solution specified in IS: 2386(Part ll) -
                 1963.


          Note- In particular cases, crushed stone sand with even higher
               proportions of fine dust than specified above may be satisfactory
               and the limit so permitted may be subject to approval of Engineer -
               in-charge.
6.3.4.2 Grading of Sand:


        6.3.4.2.1 The particle size grading of sand shall be as specified in Table
ll for masonr y mortars and for plaster wor k for external as well as internal walls
and ceiling.


             Table ll - Grading of Sand for use in Masonry and Plaster Mortars



                                                                                           194
TECHNICAL SPECIFICATION

               IS:Sieve                   For use in masonry               For internal and external
               Designation                mortar, percentage               wall and ceilling plaster,
                                          passing by mass                  percentage passing by mass


                     9.5 mm                     -                                    100
                     4.75 mm                    100                                  95 to 100
                     2.36 mm                    90 to 100                            95 to 100
                     1.18 mm                    70 to 100                            90 to 100
                     600 micron                 40 to 100                            80 to 100
                     300 micron                     5 to 70                          20 to 65
                     150 micron                     0 to 15                           0 to 15


Volume I –Sec..III                Specifications For Irrigation Projects Nov. 1991                     6/8



       6.3.4.2.2 The various sizes of particles of which the sand is composed
shall be uniformly distributed through out the mass.


       6.3.4.2.3 The required grading may often be obtained by screening and/or
by blending together either natural sand or crushed stone screenings, which
are, by themselves usuitable.


       6.3.4.2.4 The sand for masonry mortars whose grading falls outside the
specified limits due to excess or deficienc y of coarse or fine particles may be
processed to comply with the standard by screening through a suitable sizes of
sand particles. Based on test results and in the light of pr actical experience with
the use of local materials, deviation in grading of sand given in para 6.3.4.2.1
above may be considered by the Engineer -in-charge.


       6.3.4.2.5 Sand for plaster where the grading falls outside the limits of
grading zones of sieves ot her than 600 micron IS Sieve, by a total amount not
exceeding 5 percent, it shall be regarded as falling within the grading. This
tolerance shall not be applied to percentage passing the 600 micron IS Sieve or
to percentage passing any other sieve size on the finer limit.


       6.3.4.2.6 For crushed stone sands for plaster, the permissible limit on
150 micron nominal aperture size sieve increased to 20 percent. This does not
affect the 5 percent allowance permitted in para 6.3.4.2.5 applying the other
sieve sizes.


       6.3.4.3 Bulking of Sand - In the nominal mortar mixes specified by
volume, sand is assumed to be dry. Dry and saturated sands have almost the
same volume, but damp sand increase in volume. Bulking depends primarily
upon moisture content and margin ally on grading of sand. Due allowance for
bulking of sand also be made, while preparing the mortar mixes based on
volume measurements.


      The bulking allowance for any sample of sand shall be got determined in
accordance with procedure given in Appendix -ll. The following Table lll gives the



                                                                                                       195
TECHNICAL SPECIFICATION

relation between the moisture content and percentage of bulking, which may be
used as a rough guidance.


                                                  TABLE III


                              Moisture content                                   Bulking percent
                              percentage by weight                                  (Volume)


                                    2                    ...            ...            15


                                    3                    ...            ...            20


                                    4                    ...            ...            25


                                    5                    ...            ...            30




       6.3.5 Soil : Soil for making mud mortar shall have suitable plasticity. The
soil shall be free from vegetable roots, stone, gravel (particle size greater than
2 mm) kankar; coarse sand and harmful and efflorescent salts. Soil shall not be
collected from locality aff ected by white ants. The plasticity index of soil shall
be between 6 and 10. The sulphate content shall not exceed 0.1 percent.
Coarse material (coarser than 3.35 mm) in soil shall not exceed 10 percent by
weight.


       6.3.6 Water : W ater used for making masonry mortars shall be clean and
free from injurious quantities of deleterious materials. Potable water is generally
considered satisfactor y for use in masonry mortar.
Volume I –Sec..III                  Specifications For Irrigation Projects Nov. 1991                     6/9



         6.3.6.1 Permissible limits for solids shall be as given in Table IV below : -


                                                  TABLE IV


                     Solids                                                   Permissible Limit (Max.)


                     Organic                       ...            ...            200 mg/L
                     Inorganic                     ...            ...            3000 mg/L
                     Sulphates(as SO4)             ...            ...            500 mg/L

                     Chloride (as Cl)              ...            ...            2000 mg/L
                     Suspended Matter              ...            ...            2000 mg/L


6.4 GRADE OF MORTAR :




                                                                                                         196
TECHNICAL SPECIFICATION

      6.4.1 Masonr y mortars shall preferably be sp ecified by the grade in terms
of their minimum compressive strength as given in Appendix -lll. Masonry
mortars in terms of mix proportion which gives the range of compressive
strength (at the age of 28 days) values are also given in Appendix -lll for
guidance.


6.5 CRITERIA FOR SELECTION OF MASONRY MORTARS:
       6.5.1 The selection of masonry mortars from durability considerations will
have to cover both the loading and exposure conditions of the masonry. The
requirements for masonr y mortar shall be as specified i n para 8 B.3 of Chapter-
8 B for “Dam and Apurtenant W orks” and para 6.5.1.1 to 6.5.1.6 below for other
works.


       6.5.1.1 In the case of masonry exposed frequently to rains and where
there is further protection by way of plastering or rendering or other finis hes,
the grade of mortar shall not be less than MM 0.7 but shall preferably be of
grade MM 2. W here no protection is provided, the grade of mortar for external
walls shall not be less than MM 2.


       6.5.1.2 In the case of load bearing internal walls, the grad e of mortar
shall preferably be MM 0.7 or more for high durability but in no case less than
MM 0.5.


      6.5.1.3 In the case of masonry of foundations laid below damp proof
course, the grades of mortar for use in masonry shall be as specified below.


           (a)       W here soil has little moisture, masonry mortar of grade not less
                     than MM 0.7 shall be used.


           (b)       W here soil is ver y damp, masonry mortar of grade preferbly MM 2
                     or more shall be used. But in no case shall the grade of mortar be
                     less than MM 0.7; and


           (c)       W here soil is saturated with water, masonry mortar of grade MM 3
                     shall be used but in no case shall the grade of mortar be less than
                     MM 2.


      6.5.1.4 For masonr y in buildings subject to vibration of machinery the
grade of mortar shall not be less than MM 3.


       6.5.1.5 For parapets, where the height is greater than thrice the
thickness, the grade of masonry mortar used shall not be less than MM 3. In the
case of low parapets, the grade of mortar shall be the same as used in the wall
masonry below.


      6.5.1.6 The grade of mortar for bedding joints in masonry with large
concrete blocks shall not be less than MM 3.
Volume I –Sec..III              Specifications For Irrigation Projects Nov. 1991    6/10



6.6 PREPARATION OF MASONRY MORTARS :


                                                                                    197
TECHNICAL SPECIFICATION

6.6.1 Proportioning :

         The mortar mix will be preferably specified by volume. W here the mix
design is prescribed on weight basis but weigh batching is not practicable, the
batching may be done by converting the design mix into equivalent volume on
basis of unit weight of materials in loosely placed condition which shall be found
by actual field measurement. Loosely placed condition is achieved by pouring or
filling the material in the container loosely, that is without giving an y jerk to the
container.
6.6.2 Cement Mortar :

       6.6.2.1 Proportioning - Cement shall be proportioned only by full bags.
Sand in specified proportion shall be measured in boxes of suitable size on the
basis of dry volume. In case of damp sand its quantity s hall be increased
suitably to allow for bulkage which shall be determined as per para 6.3.4.3.

       6.6.2.2 Preparation - Mixing shall be done preferably in a mechanical
mixer. If done by hand, the operation shall be carried out on a clean water tight
platform . Cement and sand shall be mixed dry in the required proportions to
obtain uniform colour. The required quantity of water shall then be added and
the mortar mixed for atleast three minutes after addition pf water. In the case of
hand mixing, the mortar sha ll be hoed back and forth for 5 to 10 minutes with
addition of water.

        6.6.2.3 Generally, only as much quantity of cement mortar as would be
sufficient for 30 minutes work shall be mixed at a time.

       6.6.2.3 The Engineer-in-charge shall if necessary specify the use of
suitable air-entraining agents to improve the quality and workability of mortar.
The amounts of air entraining agents used shall be such as will affect the
entrainment of 8 percent to 12 percent of air by volume of mortar.

6.6.3 Lime Mortar :

      6.6.3.1 Proportioning - The ingredients in specified proportions shall be
measured in boxes of suitable size. Sand shall be measured on the basis of dry
volume and in accordance with para 6.6.2.1

6.6.3.2 Preparation:

       6.6.3.2.1 If lime is supplied in the form of quick lime it shall be slaked
and run into putty in accordance with para 6.3.2.5. Putty and sand in the
specified proportions shall be mixed with or without addition of water on a dry
water proof platform or in a mixer. The mix shall then be fed i nto a mortar mill
with the required addition of water to the required working consistenc y. The
mortar shall be raked continuously during grinding, particularly in the angular
edges of the mortar mill. The mixing shall be done for 180 revolutions or for
minimum of 3 hours, till ever y particle of aggregate is coated uniformly with the
cementitious material. Alternatively, a mechanical mortar mill may be used for
grinding for 3 minutes.

       6.6.3.2.2 If dr y hydrated lime is used, the sand and lime in specified
proportions shall be mixed dr y first, and shall then be fed into mortar mill with
required additions of water to the required working consistenc y. The mixing
shall be done in accordance with para 6.6.3.2.1 above.

        6.6.3.2.3 Generally, only as much quantity of lime mortar (except made
with class A lime) as would be sufficient for a day’s work shall be mixed at a
time. If eminently hydraulic lime (class A) is present as an ingredient, the mortar shall be
used within 4 hours after grinding.

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                                                                                        198
TECHNICAL SPECIFICATION


6.6.4 Lime Pozzolana Mixture Mortar :

       6.6.4.1 Proportioning - The ingredients in specified proportions shall be
measured in boxes of suitable size. Sand shall be measured on the basis of its
dry volume as indicated in para 6.6.2.1.

      6.6.4.2 Preparation - Mortar using lime pozzolana mixture shall be
prepared in the same manner as described in para 6.6.2.2.

       6.6.4.3. Mortar with lime pozzolana mixture of type LP 20 and LP 40 as
binder shall be used within 4 hours from the time of mixing of the mortar,
whereas mortars which have hydraulic lime (Class B) or fat lime (Class C) and
pozzolana or lime pozzolana mixture of type LP7 as ingredients , but do not have
either portland cement or eminently hydraulic lime (Class A) shall be used
within 12 to 24 hours from the time of mixing of the mortar.

6.6.5 Cement Lime Mortar :

       6.6.5.1 Proportioning - Cement, lime putty/dry hydrated lime and sand
shall be taken in proportions as specified in the item of work. The unit of
measurement for cement is a bag. Lime in the form of putty in specified
proportion shall be measured in accordance with para 6.6.3.1. Sand shall be
measured on the basis of its dry vo lume in accordance with para 6.6.2.1.

6.6.5.2 Preparation :

       6.6.5.2.1 W here coarse sand is used, the lime putty and sand in the
required proportions shall; after preliminary mixing on a watertight platform, with
necessar y addition of water, be ground in a mortar mill to the required working
consistenc y taking care to rake up continuously the mortar particularly at the
corners. The mixing shall be done for 180 revolutions or for minimum 3 hours till
every particle of aggregate is coated uniformly with the cementitious material.
This mix shall then be transferred to a mechanical mixer to which the required
quantity of cement is added and the content mixed for at least 3 minutes.

       6.6.5.2.2 W here fine sand is used the mixing operation shall be done in
same manner as in 6.6.5.2.1, except that grinding may be omitted for
preliminar y mixing of lime putty and sand. W hen factory made dry hydrated lime
conforming to IS: 712-1984 is used, grinding of lime and sand in the mortar mill
is not necessar y.

      6.6.5.2.3 If the mixture of lime putty and sand is not used immediately for
mixing with cement, it shall be kept protected from drying out till the time of use.

       6.6.5.2.4 W here hand mixing is necessary cement and sand shall be
mixed dr y thoroughly on clean tight masonr y platform or in troughs. Lime putty
shall be mixed with water to make milk of lime,. it shall be added to mixture of
cement and sand. The mixture shall be kneaded back and forth for about 10
minutes with addition of milk of lime to obtain mortar of workab le consistenc y.
       6.6.5.3 Mortar shall be used as soon as possible after mixing and
maximum within 2 hours. Mortar unused for more than 2 hours shall be rejected
and removed from the site of work. Mixture of lime putty and sand can be kept
for 72 hours for preparation of lime cement mortar in respect of class B and C
lime and for 6 hours in case of class A lime provided it is kept damp and not
allowed to dr y.
6.6.6 Mud Mortar :
       6.6.6.1 Preparation - Mortar shall be prepared from none but well
tempered clay or good brick earth free from vegetation, gravel, kanker,
efflorescencing salts, white ants and other rubbish etc. The dry soil shall be
reduced to fine powdered state and mixed with water in a pit. Fibrous
reinforcing material such as chopped straw not lo nger than 20 mm, in the


                                                                                199
TECHNICAL SPECIFICATION



Volume I –Sec..III            Specifications For Irrigation Projects Nov. 1991          6/12



preparation of 30 to 35 Kg./cu.m soil , shall be added while mixing. the mixture
shall be allowed to mature for a period of not less than seven days. During this
period, it shall be worked up at intervals with feet and spades so as to get
pugged into a homogenous mass free from lumps and clods.
       The mortar when ready shall be for such a consiste nc y that it will readily
slide off the face of trowel but shall not be so wet that the mortar parts into
large drops while falling.


         Normally the mortar made on a day shall be used as soon as possible.


        6.6.6.2 At site of the work, normally pits shall not be dug at or near the
site of work for obtaining the soil. However, if under special circumstances, pits
are allowed to be dug by the Engineer -in-charge, these shall not be deeper than
1.50 metres and shall be filled and dressed properly as soon as possibl e. The
top 60 cm shall be filled with good soil in 20 cm layers with clods broken,
watered, rammed and consolidated. The bottom layers may be filled with
building rubbish mixed with soil laid in 20 cm layers watered, rammed and
consolidated.


       6.7 RETEMPERING OF MORTARS: In the case of the mortar using
cement, the mortar that has stiffened because of evaporation of water from the
mortar may be retempered by adding water as frequently as needed to restore
the requirementsof consistenc y, but this retempering s hall be permitted only
within 60 minutes from the time of addition of cement. Mud mortar can be
retempered by addition of water and kneading any time if it dries up.


6.8 CONSISTENCY OF MASONRY MORTARS:


       6.8.1 The water shall be enough to maintain the flui dity of the mortar
during application, but at the same time it shall not be excessive leading to
segregation of aggregates from the cementitious material. The quantity of water
needed for maintaining consistenc y or fluidity will also depend upon the
masonry to which the mortar is used; for example, thinner joints will require
greater fluidity; bed joints subject to heavy pressure may require stiffer mortar,
also the mortar shall be able to hold the water against suction by the masonry
unit, particularly in the case of burnt clay and concrete products.


      6.8.1.1 The consistency of mortar shall be measured in accordance with
the procedure given in Appendix -IV and the following values of penetration are
recommended.


           For laying walls with solid bricks             ...          90 to 130 mm


           For laying perforated bricks.                  ...          70 to 80 mm


           For filling cavities.                          ...          130 to 150 mm.




                                                                                        200
TECHNICAL SPECIFICATION




                                                  -------------




Volume I –Sec..III               Specifications For Irrigation Projects Nov. 1991      6/13

                                             APPENDIX - I


                      Determination of Clay, Fine Silt and Fine Dust in Sand
                                      (Sedimentation Method)
                                            (Para 6.3.4.1.3)


       1. OBJECT : This is a gravimetric method for determining the clay, fine
silt and fine dust, which inc ludes particles upto 20 micron. Differences in the
nature and density of materials or in the temperature at the time of testing may
vary the separation point.


         2. APPARATUS : The apparatus shall consist of the following:


           (a)       A water tight screw-topped glass jar of dimensions similar to a 1
                     kg fruit preserving jar.


           (b)       A device for rotating the jar about its long axis, with this axis
                     horizontal, at a speed of 80  20 rev/min.


           (c)       A sedimentation pipette of the Andresson type of approximately 25
                     ml capacity and of the general form as indicated in figure 1*. This
                     consists mainly of a pipette fitted at the top with a two -way tap
                     and held rigidly in a clamp which can be raised or lower ed as
                     required, and which is fitted with a scale from which the changes
                     in height of the pipette can be read.


                     The volume of the pipette A, including the connecting bore of the
                     tap B, is determined by filling with distilled water; by reversing the


                                                                                       201
TECHNICAL SPECIFICATION

                     tap, the water is run out into a bottle, weighed and the volume
                     calculated.


           (d)       A 1000-ml measuring cylinder.


           (e)       A scale or balance of capacity not less than 10 kg, readable and accurate to one gram.


            (f)      A scale or balance of capacity not less than 250 g, readable and
                     accurate to 0.001 g.


           (g)       A well-ventilated oven, thermostatically controlled, to maintain a
                     temperature of 100 o to 110 o C.


        3. CHEMICALS : A solution containing 8 g of sodium oxalate per litre of
distilled water shall be taken. For u se, this stock solution is diluted with distilled
water to one tenth (that is 100,ml diluted with distilled water to one litre).


      4.TEST SAM PLE: The sample for test shall be prepared from the main
sample taking particular care that the test sample contains a correct proportion
of the finer material. The amount of sample taken for test shall be in a
accordance with Table below:-
                                                     TABLE :
             W eight of Sample for Determination of Clay, Fine Silt and Fine Dust


                           Maximum Size present in                    Approximate Weight of
                       Substantial Proportions(mm.)                      Sample for Test(kg.)


                                        63 to 25                             6
                                        20 to 12.5                           1
                                        10 to 6.3                            0.5
                                        4.75 or smaller                      0.3


 * For figure see Specifications published by E-in-C.
Volume I –Sec..III                  Specifications For Irrigation Projects Nov. 1991                          6/14



       4.1 All in aggregates shall be separated into fine and coarse fractions by
sieving on a 4.75 mm IS Sieve and the two samples so obtained shall be tested
separately.


5. TEST PROCEDURE :


       5.1 Method for Fine Aggregate - Approximately 300 g of the sample in
the air-dr y condition, passing the 4.75 mm IS Sieve, shall be weighed and
placed in the screw topped glass jar, together with 300 ml of the diluted sodium
oxalate solution. The rubber washer and cap shall be fixed, care being taken to



                                                                                                              202
TECHNICAL SPECIFICATION

ensure water tightness. The jar shall then be rotated about its long axis, with
this axis horizontal , at a speed of 80 + 20 rev/min. for a period of 15 minutes.


       At the end of 15 minutes, the suspension shall be poured into the 100 ml
measuring c ylinder and the residue washed by gentle swirling and decantation
of successive 150 ml portions of sodium oxalate solution, the washing being
added to the cylinder until the volumes is made upto 1000 ml. The determination
shall be completed as described in after para below.


       5.2 Method fo r Coarse Aggregate - The weighed sample shall be placed
in a suitable container, covered with a measured volume of sodium oxalate
solution (0.8 g per litre), agitated vigorously to remove all adherent fine material
and the liquid suspension transferred to the 1000-ml measuring c ylinder. This
process shall be repeated as necessary until all clayey material has been
transferred to the c ylinder. The volume shall be made upto 1000 ml with sodium
oxalate solution and the determination completed as described in p ara after
below.
        The suspension in the measuring c ylinder shall be thoroughly mixed by
inversion and the tube and contents immediately placed in position under the
pipette. The pipette A shall then be gently lowered until the tip touches the
surface of the liquid, and then lowered a further 10 cm into the liquid. Three
minutes after placing the tube in position, the pipette A and the bore of a tap B
shall be filled by opening B and applying gentle suction at C. A small surplus
may be drawn up into the bulb between tap B and tube C. This shall be allowed
to run away and solid matter shall be washed out with distilled water from E.
The pipette shall t hen be removed from the measuring cylinder and its contents run to a
weighed container, any adherent solids being washed into the container by distilled water
from E through the tap B.

      The contents of the container shall be dried 100 o to 110 o C to constant
weight, cooled and weighed.
      6. CALCULATION: The proportion of fine silt and clay or fine dust shall
then be calculated from the following formula


        Percentage of clay and fine silt or fine dust = 100        1000W 2 -0.8


                                                              W1      V

        W here,


        W1        = W eight of the original sample in gram,

        W2        = W eight of the dried residue in gram,

         V        = Volume in ml of the pipette, and
        0.8       = W eight of sodium oxalate in one litre of the diluted solution in
                     gram.


        Note :-      No correction is made for water soluble salts which may be
                  present in the sand, since the amount of such salts shall be
                  small.
       7. REPORTING OF RESULTS : The Clay, fine silt and fine dust content
shall be reported to the nearest 0.1 %.



                                                                                     203
TECHNICAL SPECIFICATION

                                                                              
Volume I –Sec..III               Specifications For Irrigation Projects Nov. 1991             6/15



                                             APPENDIX -II


                         Field Method for determination of Bulking of Sand


      1.OBJECT :This method of test covers the field method for determining
the necessar y adjustment for bulking of fine aggregate.


       2.GENERAL : Sand brought on to a building site or other works may
contain an amount of moisture which will cause it, when loosely filled into a
container, to occupy a large volume than it would occupy if dry. If the sand is
measured by loose volume of the sand, in order that the amount of sand put into
the concrete may be the amount intended for the nominal mix used (based on
dry sand). It will be necessary to increase the volume of sand by the
‘precentage’ bulking. The correction to be mad e is only a rough approximation,
because the s ystem of measurement by loose volume is a rough method at the
best, but a correction of the right order can easily be determined and should be
applied in order to keep the concrete uniform.


3. PROCEDURE :


       3.1 The procedure to be adopted may be varied, but two methods are
suggested in 3.2 and 3.3. Both depend on the fact that the volume of inundated
sand is the same as if the sand were dry.


       3.2 Put sufficient quantity of the sand loosely into a container until it is
about two-thirds full. Level off the top of the sand and pushing a steel rule
vertically down through the sand at the middle to the bottom, measure the
height. Suppose this is h cm.


      3.2.1 Empty the sand out of the container into another container w here
none of it will be lost. Half fill the container with water. Put back about half the
sand and rod it with a steel rod, about 6 mm in diameter, so that its volume is
reduced to a minimum. Then add the remainder of the sand and rod in the same
way. Smooth and level the top surface of the inundated sand and measure its
depth at the middle with the steel rule suppose this is h’cm.


       3.2.2 The percentage of bulking of the sand due to moisture shall be
calculated from the formula.


                 Percentage bulking = (h/h’ -1) x 100


        3.3 In a 250 ml measuring c ylinder, pour the damp sand (cosolidated by
shaking) until it reaches the 200 ml mark. Then fill the c ylinder with water and
stir the sand well; the water shall be sufficient to submerge the sand completely.
It will be seen that the sand surface is not below its original level. Suppose the
surface is at the mark of Y ml. The percentage of bulking of sand due to
moisture shall be calculated from the formula.


                                                                                              204
TECHNICAL SPECIFICATION



                     Percentage bulking = (200/Y -1) x 100


4. REPORT OF RESULTS : Report of percentage bulking of the sand to the
nearest whole number.




Volume I –Sec..III               Specifications For Irrigation Projects Nov. 1991                        6/16




                                               APPENDIX - III


                                         Grade of Masonry Mortars
                                                  (Para 6.4)


Sl.    Grade                             Mortar Mix (By Loose Volume)                      Compressive
No.                     Cement       Lime     Pozzolana    Lime Pozzolana       Sand          Strength
                                                              Mixture                      st 28 Days

                                                                                            (N/mm2)


1      2                3            4           5                6                 7           8




1      MM 0.5           0        1 B or E        0                0                 3
2                       0        0               0                1                 1.25      0.5 to 0.7
                                                                  (LP-7)
3                       0        1 C or D        1                0                 2
4      MM 0.7           0        0               0                1                 1.5
                                                                  (LP-20)
5                       0        0               0                1                 2.25
                                                                  (LP-40)




                                                                                                         205
TECHNICAL SPECIFICATION

6                    1    3 C or D      0                  0                 12         0.7 to 1.5
7                    1    0             0                  0                 8
8                    1    0             0.4*               0                 10
9      MM 1.5        0    0             0                  1                 1.25
                                                           (LP-20)
10                   0    0             0                  1                 2
                                                           (LP-40)


11                   1    0             0                  0                 7           1.5 to 2
12                   1    0             0.4*               0                 8.75
13                   0    1A            0                  0                 3
14     MM 2          0    1A            0                  0                 2


15                   0    1 C or D      3*                 0                 0              2 to 3
16                   0    2 C or D      0                  0                 9
17                   0    0             0                  1                 1
                                                           (LP-20)
18                   0    0             0                  1                 1.75
                                                           (LP-40)
19     MM3           0    1 C or D      2*                 0                 0
20                   1    1 C or D      0                  0                 0
21                   1    0             0                  0                 6
22                   0    1A            0                  0                 1


23                   1@   0             0.21*              0                 4.2            3 to 5
24                   0    0             0                  1                 1.5
                                                           (LP-40)




Volume I –Sec..III        Specifications For Irrigation Projects Nov. 1991                     6/17




Sl.    Grade                   Mortar Mix (By Loose Volume)                         Compressive




                                                                                               206
TECHNICAL SPECIFICATION

No.                  Cement       Lime   Pozzolana   Lime Pozzolana   Sand      Strength
                                                        Mixture              st 28 Days

                                                                              (N/mm2)


1      2             3        4             5             6           7              8




25                   1        0             0.4*          0           7.5            3 to 5
26                   1        0             0             2           12
                                                          (LP-20)
27     MM 2          1        0 to 1/4 B,   0             0           4
                              C,D or E


28                   1        0             0             0           5             5 to 7.5
29                   0        0             0             1           1
                                                          (LP-40)
30                   1        0             0.4           0           6.25
31                   1        0             0.4           0           5
32     MM 7.5        1        1/4 C or D    0             0           3
33                   1        1/2 C or D    0             0           4.5


34                   1        0             0             0           4           7.5 and above
35                   1@       0             0.2*          0           2.1
36                   1        0             0             0           3
37                   1        0             0.4           0           3.75
38     MM 7.5        1        0             0             1           8
                                                          (LP-20)




Note 1 -         A,B,C,D and F denote the classes of limits to be used (see para
                 6.3.2.1).


                 2 - The strength values of lime mortars given in the table are after
                 wet grinding of the mortar ingredients.


       3 -       The compressive strength shall be determined in accordance with
                 the procedure given in Appendix -A of IS: 2250-1981.


       4 -       LP 7, LP 20 and LP 40 are three types of pozzolana mixture
                 conforming to requirements specified in para 5 of IS: 4098 -1983.


        * -      Pozzolana of minimum lime reactivity of 4N/mm 2 .

                                                                                           207
TECHNICAL SPECIFICATION




Volume I –Sec..III               Specifications For Irrigation Projects Nov. 1991   6/18




                                             APPENDX-IV


                          Determination of Consistency of Masonry Mortar


1. OBJECT :


         To determine the consistency of masonry mortar.


2. APPARATUS* :


       2.1 This shall consist of the standard cone weighing 300  2g, 150 mm in
height and a diameter at a base of 75 mm. The cone is mounted on a vertical
shaft fastened to the adjustable holder. The holder has a mechanism which
releases the shaft. The apparatus has also an instrument dial which records the
depth of penetration of the cone inverted mortar mix kept in a conical container
below. The conical container for mortar be 180 mm deep with a diameter at top
of 150 mm.


           2.2 Flow Table - This shall be as given in IS: 5512 -1969.


           2.3 Tamping Rod - A metal bar 25 mm square and 200 mm long.


3. PROCEDURE :


                                                                                    208
TECHNICAL SPECIFICATION



       The conical container shall be fixed with mortar mix to a level that is 1 cm
below its rim. Mortar mix shall be placed in a conical mould in one continuous
operation shall be compacted by tamping rod. The mould fill ed with mortar mix
is bumped 5 or 6 times over a flow table so as to level the surface of the mortar.
The container shall be placed over the base below the penetration cone of the
apparatus. The apex of the penetrating cone shall be brought first in contac t
with the surface of the mortar and the cone clamped in position. The instrument
dial is set to be in contact with a cone at this position. The cone is then
released and allowed to sink into the mortar mix. After the cone has stopped
penetrating into the mortar, the dial is once more set to record the position of
the cone and the difference between dial readings before and after penetration
gives the depth of penetration of the cone into the mortar.


4. REPORT :


      The average of the           two    determination         shall    be    reported   as   the
consistenc y of the mortar.


5. FIELD TEST :


       For qucik field determination, the procedure may be further simplified.
The shaft of the cone shall be held by hand in a perpendicular position so as to
be in contact with the surface of the m ortar and gently released to sink into the
mortar taking care that the shaft remains vertical during penetration. The depth
of penetration may be computed from the measurement of the wetted depth
along the surface of the cone.




        * For figures see Specifica tions published by E-in-C.




                                                                                               




Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991                   7/1




                           CHAPTER 7 - Filling Foundations,
                                             and
                          CHAPTER 16 - R.C.C. and Form Work




                                                                                               209
TECHNICAL SPECIFICATION

7.1 REFERENCES :


       IS : 269-1989          -   Specification for 33 Grade Ordinary Portland Cement (Fourth
                                  revision).

       IS : 383-1970          -   Specification for coarse & fine aggregate from natural source
                                  for concrete (second revision)

       IS : 455-1976          -   Specification     for      Portland    slag     cement      (third
                                  revision)(amendment Nos.1,2,3,4,5,6 & 7).

       IS : 456-1978          -   Code of practice for Plain & Reinforced concrete (second
                                  revision)(Amendment No.1).

       IS : 457-1957          -   Code of practice for general construction of Plain and
                                  Reinforced Concrete for dams and other massive structures.

       IS: 516-1959           -   Method of test for strength of concrete (Amendment No.1).

       IS: 1199-1959          -   Code of sampling & analysis of concrete.

       IS: 1343-1980          -   Code of practice for Prestress concrete (first revision).

       IS: 1489-1976          -   Specification   for     Portland   pozzolana    cement   (second
                                  revision)(Amendment Nos. 1,2,3,4,5,6&7).

       IS: 1791-1985          -   Specification for batch type concrete mixer (second revision).

       IS: 2386(Pt.1)-1977    -   Method of test for aggregates for concrete Part-1, Particle
                                  size and shape (Amdt.No.1)

       IS:2386(Pt.2)-1977     -   Method of test for aggregates for concrete Part-2, Estimation
                                  of deleterious material and organic impurities (Amdt. No. 1).

       IS: 2386(Pt.3)-1977    -   Method of test for aggregates for concrete part-3, Specific
                                  gravity, density voids, absorption & bulking.

       IS:2386(Pt.4)-1977     -   Methods of test for aggregates for concrete Part-4,
                                  Mechanical properties (Amdt. Nos. 1,2&3).

       IS:2386(Pt.5)-1977     - Methods of tests for aggregates for concrete Part-5,
                                  Soundness.

       IS:2386(Pt.6)-1977     -   Methods of test for aggregates for concrete Part-6, Measuring
                                  mortar making properties of fine aggregates (Amdt.No.1).

       IS:2386(Pt.7)-1977     -   Methods of test for aggregate for concrete Part-7, Alkali
                                  aggregate reactivity.

       IS:2386(Pt.8)-1977 -       Methods of test for aggregates for concrete Part-8,
                                  petrigraphic examination.

       IS:2405(Pt.ll)-1980    -   Specification for Industrial Sieves Part-2, Perforated plants.

       IS:2430-1986           -   Method for sampling of aggregates for concrete.

       IS: 2505-1980          -   General requirements for concrete vibretors immersion type.

       IS: 2506-1985          -   General requirements for screed board concrete vibrators.



                                                                                               210
TECHNICAL SPECIFICATION




Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991                   7/2



       IS: 2514-1963        -   Specification for concrete vibrating tables.

       IS: 3535-1986        -   Methods of sampling, hydraulic cements (first revision).

       IS: 3812-1981        -   Specification for fly ash for pozzolana and admixture (first
                                revision).

       IS: 4031-1988        -   Methods of physical tests for hydraulic cement.

       (Part 1 to Pt.13)

       IS: 4032-1985        -   Method of chemical analysis of hydraulic cement (first
                                revision).

       IS: 4082-1977        -   Recommendation on stacking and storage of construction
                                materials at site (first revision).

       IS:4634-1968         -   Methods of testing, performance of batch type concrete
                                mixers.

       IS: 4656-1968        -   Specification for form vibrators for concrete.

       IS: 4925-1968        -   Specification for concrete batching and mixing plant.

       IS: 6452-1972        -   Specification for high alumina cement for structural use
                                (Amendment Nos.1,2 & 3).

       IS: 6461-1972        -   Glossary of terms relating to cement concrete.

       (Pat 1 to 7)

       IS: 6461-1973        -   Glossary of terms relating to cement concrete.

       (Part 8 to 12)

       IS: 6909-1973        -   Specification for super sulphate cement (Amendment Nos.
                                1,2,3 & 4).

       IS: 7861 (Pt.1)-1975 -   Code of practice for extreme weather concreting Part, 1 Hot
                                weather.

       IS: 8041-1978        -   Specification for rapid hardening portland cement (first
                                revision) (Amendment Nos. 1,2,3&4).

       IS: 8112-1976        -   Specification    for   43   grade     ordinary   portland   cement
                                (Amendment Nos.1,2,3,4,5&6).

       IS: 9103-1979        -   Specification for admixtures for concrete.

       IRC:21-1972          -   Standard specifications and Code of practice for road
                                bridges.




                                                                                              211
TECHNICAL SPECIFICATION

       SP:23-1982         -   Hand    book     of   concrete      mixes      (based   on   Indian
                              Standard)(with amendment No.1).

       SP:24-1983         -   Explanatory hand book on Indian Standard code for plain &
                              reinforced concrete (IS:456-1978).

                          -   Specification for Road & Bridge Work (By Ministry of Shipping
                              & Transport) (Road wing).

                          -   Gandhi Sagar Dam Specifications.

                          -   Concrete Manual (US Department of the Interior Water &
                              Power Resources Service).

                          -   Report of committee on cost control, River valley projects,
                              Vol-lll Jan. 1981(Govt. of India Ministry of irrigation).




Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991                   7/3



7.2 TERMINOLOGY:
        Abrahams Law - A rule stating that with given concrete materials and
conditions of test, the ratio of the amount of water to the amount of cement in
the mixture determines the strength of concrete provided that mixture is of a
workable consistenc y.
        Absorbed Moisture - Moisture that has entered a solid material by
absorption and has physical properties not substantially different from ordinary
water at the same temperature and pressure.
        Accelerator- A substance which when added to concrete, mortar or
grout, increases the rate of hydration of the hydraulic cement, shortens the time
of setting, or increases the rate of hardening or strength development.
        Addition/Additive - A material that is inter-ground or blended in limited
amounts into a hydraulic cement during manufacture either as a “processing
addition” to aid in manufacturing and handling the cement or as a “functional
addition” to modif y the use properties of the finished product.
        Absorbed Water-       W ater held on surface of a material by electro
chemical forces and having physical properties substantially different from tho se
of absorbed water or chemically combined water at the same temperature and
pressure.

      Absorption - Development at the surface of a liquid or solid of a higher
concentration of a substance than exists in the bulk of the medium; especially
formation of one or more layers of molecules of gases, or dissloved substances,
or of liquids at the surface of a solid, such as cement, cement paste, or
aggregate, or of air entraining agents at the air -water interfaces; also the
process by which a substance is absorbed .

      Aggregate - Granular material, generally inert, such as manufactured
sand, gravel, crushed gravel, crushed stone, and air cooled iron blast furnace
slag which when bound together into a conglomerated mass by a matrix forms
concrete or mortar.


                                                                                            212
TECHNICAL SPECIFICATION


       Aggregate, All in - Material composed of a mixture of coarse aggregate and fine
aggregate.

       Aggregate, Coarse - Aggregate most of which is retained on 4.75mm, IS:
Sieve and containing only so much of finer material, as is permitted by the
specifications or alternatively (under differing circumstances). The portion of an
aggregate retained on the 4.75mm, IS:Sieve.

      Aggregate, Dense Graded - Aggregates graded to produce low void
content and maximum weight when compacted.

      Aggregate(Fine) - Aggregates most of which passes 4.75mm IS: Sieve
and containing only so much coarser material as is permitted for various grading
zones in the specifications.

      Aggregates, Gap Graded - Aggregates having a particle size distribution
where one or more sizes are missing.

       Aggregate, Graded - Aggregate comprising of a portion of all sizes from
a given nominal maximum to 4.25 mm. W hen these sizes are so proportioned as
to give a definite grading, it is a well graded aggregate.

       Aggregate, Heavy Weight - Aggregate of high spec ific gravity such as
barite, magnetite, limonite, liemenite iron, or steel used to produce heavy
concrete of high density concrete specially for shielding against nuclear
radiation.

       Aggregate, Light Weight - Aggregate of low bulk specific gravity, such
as expanded or sintered clay, slate, slag, fly ash verniculite, or pumice or
natural pumice and scoria used to produce light weight concrete.
Volume I –Sec..IV          Specifications For Irrigation Projects Nov. 1991       7/4



      Aggregate, Maximum Size of - The largest size of aggregate particles
present in sufficient quantity to influence the physical properties of concrete,
generally designated by the stadard sieve nearest to the sieve size on which
over 10 percent weight is retained.

       Aggregate, Reactive - Aggregate containing substances capable of
reacting chemically with the products of solution or hydration of the portland
cement in concrete or mortar under ordinary conditions of exposure, resulting in
some cases in harmful expansion, cracking or staining.

      Aggregate, Blending - The process of inter-mixing two or more
aggregates to produce a different set of properties; generally but not
exclusively, to improve grading.

      Air Content - The volume of air voids in cement paste, mortar, or
concrete, exclusive of pore space in aggregate particles, usually expressed as a
percentage of total volume of the paste, mortar or concrete.

       Alkali - Salts of alkali metals, principally sodium and potassium
specifically sodium and potassium occuring in constituents of concrete or
mortar, usually expressed in chemical anlysis as the oxides Na 2 O and K 2 O.

       Alkali - Aggregate Reaction- Chemical reaction in mortar or concrete
between alkalies (sodium and potassium) from por tland cement or other sources
and certain constituents of some aggregates; under certain conditions,
deleterious expansion of the concrete or mortar may result.




                                                                                  213
TECHNICAL SPECIFICATION

        Alkali Reactivity(of aggregate) - Succeptibility of aggregate to alkali aggregate
reaction.
        Anchor - In prestressed concrete, to lock the stressed tendon in position
so that it will retain its stressed condition; in precast concrete construction, to
attach the precast units to the building frame; in slabs on grade or walls, to
fasten to rock or adjacent structures to prevent movement of the slab or wall with
respect to the foundation, adjacent structure or rock.
        Arenaceous - Composed primarily of sand; sandy.
        Argillaceous - Composed primarily of clay or shales; clayey.

      Ball Test - A test to determine the consistency of freshly mixed concrete
by measuring the depth of penetration of a cylindrical metal weight with a
hemispherical bottom.
      Batch - Quantity of concrete or mortar mixed at one time.

      Batch Box - Container of known volum e used to measure constituents of
a batch of concrete or mortar in proper proportions.

       Batch Mixer - A concrete mixer for c yclic operation in which the
ingredients for concrete are changed in batches; each new batch is charged into
drum of the mixer only when the preceeding batch has been discharged.

      Batching Plant - An operating installation of equipment including
batchers and mixers as required for batching or for batching and mixing
concrete materials; also called mixing plant when mixing equipment is included.

       Batching - W eighing or volumetrically measuring and introducing into the
mixer the ingredients for a batch of concrete or mortar.

        Blinding - The application of a layer of weak concrete or other suitable
material to reduce surface voids, or to p rovide a clean working surface, also the
filling or plugging of the openings in a screen or sieve by the material being
separated.

Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991         7/5




      Bulking of Sand - Increase in the bulk volume of a quantity of sand in a
moist condition over the volume of the same quantity, dry or completely
inundated.

       Centering - Specialized form work used in the construction of arches,
shell, space structures, or any continuous structure where the entire false work
is lowered (struck or decentered) as a unit to avoid the introduction of injurious
stress in any part of the structure.
       Chipping - Treatment of a hardened concrete surface by chiselling.
       Chute - A sloping trough or tube for conducting concrete, cement,
aggregate, or other free flowing materials from a higher to a lower point.

      Coarse Aggregate Factor (b/bo) - Dry rodded bulk volume of                 coarse
aggregate per unit volume of concrete; the ratio of the solid volume of          coarse
aggregate particle per unit volume of freshly mixed concrete to the solid        volume
of the coarse aggregate particle per unit volume of dry rodded                   coarse
aggregate.

      Cold Joint - A joint or discontinuity formed when a concrete s urface
hardens before the next batch is placed against it, characterized by poor bond
unless necessar y procedures are observed.

      Compacting Factor - The ratio obtained by dividing the observed weight
of concrete which fills a container size and shape when allowed to fall into it


                                                                                     214
TECHNICAL SPECIFICATION

under standard condition of test by the weight of fully compacted concrete which
fills the same container.

      Consistency - The relative mobility or ability of freshly mixed concrete or
mortar to flow, the usual measurements are, slump for concrete and flow for
mortar, cement paste or grout.

      Cube Strength - The load per unit area at which a standard cube fails
when tested in a a specified manner.

      Curing - Maintenance of humidity and temperature of freshly placed
concrete during some definite period following placing, casting or finishing to
assure satisfactor y hydration of the cementitious materials and proper
hardening of the concrete.

       Durability - The ability of concrete to resist weathering action, chemical
attack, abrasion, and other conditions of service.

      Early Strength - Strength of concrete or mortar developed soon after
placement usually during the first 72 hours.

        Expansion Joint - A separation between adjoining parts of a concrete structure which
is provided to allow small relative movements such as those caused by thermal changes to
allow small relative movements such as those caused by thermal changes to occur
independently.

      False work - (a) False work is the temporary structure erected to support
work in the process of construction. It is composed of shores, formwork for
beams (or both), and lateral bracing .

       (b) That part of form work which supports the forms u sually for a large
structure, such as bridge.
       Final Set - A degree of stiffening of a mixture of cement and water
greater than initial set, generally stated as an empirical value indicating the time
in hours and minutes required for a cement paste to stiff en sufficiently to resist
to an established degree, the penetration of a weighed test needle; also
applicable to concrete and mortar mixtures with use of suitable test procedures.
Volume I –Sec..IV            Specifications For Irrigation Projects Nov. 1991           7/6




      Final Setting time - The time required for a freshly mixed cement paste,
mortar or concrete to achieve final set.

        Flakiness Index - The flakiness index of an aggregate is the percentage of weight of
particles in it whose least dimensions (thickness) is less than three fifth of their mean
dimension.

       Form (Shutter) - (a) That part of form work which consists of sheeting
and its immediate supporting or stiffening members.

       (b) A temporar y structure or mould for the support of concrete while it is
setting and gaining sufficient strength to be self supporting.

       Form Work - Complete system of temporary structure built to contain
fresh concrete so as to form it to the required shape and dimension and to
support it until it hardens sufficiently to become, self supporting. Form work
includes the surface in contact with the conc rete and all necessary supporting
structure.
       Grading (Particle size distribution) - The distribution of particles of
granular material among various sizes; usually expressed in terms of cumulative



                                                                                        215
TECHNICAL SPECIFICATION

percentage larger or smaller than each of a series of sizes (sieve openings) or
the percentage between certain ranges of sizes (sieve openings).

       Grout-Mixture of cementitious material and aggregate to which sufficient
water is added to produce pouring consistenc y without segregation of the
constituents, or mixtur es of other compositions, such as containing PVC or
epox y resin or sodium silicate, but of similar consistenc y.
       Grouting - The process of filling with grout.

       Honeycomb - Voids left in concrete due to failure of the mortar to
effectively fill the spaces am ong coarse aggregate particles.

     Hydration - Formation of a compound by the combining of water with
some other substance, in concrete, the chemical reaction between hydraulic
cement and water.

       Hydraulic Cement - A cement that sets and hardens by chemical inter-
action with water and that is capable of doing so under water.

       Initial Set - A degree of stiffening of a mixture of cement and water less
than final set, generally stated as an empirical value indicating the time in hours
and minutes required for cement paste to stiffen sufficiently to resist to an
established degree, the penetration of a weighted test needle; also applicable to
concrete or mortar with use of suitable test procedures.

       Initial Setting Time - The time required for a freshly mixed ceme nt
paste, mortar or concrete to achieve initial set.

       Laitance - A layer of weak and non-durable material containing cement
fines from aggregates brought by bleeding water to the top of over -wet
concrete the amount of which is generally increased by o verworking or over
manipulating concrete at the surface by improper finishing or by job traffic.

       Lift - The concrete placed between two consecutive horizontal
construction joints, usually consisting of several layers or courses.
       Mass Concrete - Any volume of concrete cast in place (generally as a
monolithic structure usually incorporating a high proportion of large coarse
aggregate and a low cement content) and intended to resist applied load by
virtue of its mass; it is distinct from other types of concre te because its
dimensions are of such magnitude as to require that, measures be taken to cope
with the generation of heat and attendant volume changes.
Volume I –Sec..IV            Specifications For Irrigation Projects Nov. 1991   7/7


       Mix - A colloquial term designating a particular type of concrete mixture
also commonly called mixture.

      Mixing Speed - Rotation rate of a mixer drum or of the paddles in an
open top, pan, or trough mixer, when m ixing a batch expressed as revolutions
per minute (rpm), or in peripheral feet per minute of a point on the
circumference at maximum diameter.

      Mixing Time - The period during which the constituents of a batch of
concrete are mixed by a mixer for a stationary mixer, time is given in minutes
from the completion of mixer charging until the beginning of surcharge; for a
truck mixer, time is given in total minutes at a specified mixing speed or
expressed in terms of total revolutions at a specified mixing speed.
      Mould - (a)   A device containing a cavity into which neat cement, mortar
                    or concrete test specimens are cast; and

                    (b)    A form used in the fabrication of precast mortar or
                          concrete units.


                                                                                216
TECHNICAL SPECIFICATION


      No Fine Concrete - A concrete mixture containing little or no fine
aggregate.

        No-Slump Concrete - Concrete with slump of 25 mm or less.

       Nominal Mix - The proportions of the constituents of a proposed concrete
mixture.
       Peeling - A process in which thin flakes of mortar are broken away from a concrete
surface, such as by deterioration or by adherence of surface mortar to forms as forms are
removed.
       Penetration Resistance - The resistance, usually expressed in kg/mm 2
of mortar or cement paste to penetration by a plunger or needle under
standardized conditions.

        Plum  - A large random -shaped stone dropped into freshly placed mass
               concrete.
      Plumb - Vertical or to make vertical.
      Prestressed Concrete - Concrete in which internal stresses of such
magnitude and distribution are introduced that the tensile stresses resulting
from the service loads are counteracted to a desired degree. In reinforced
concrete the prestress is commonly introduced by tensioning the tendons.

      Proportioning - Selection of proportioning of ingredients for mortar or
concrete to make the most economical use of available materials to produce
mortar or concrete of the required properties.
      Ramming - A form of heavy tamping of concrete, grout, or the like by
means of a blunt tool forcibly applied.
      Retarder- An admixture which delays the setting of cement paste, and
hence of mixtures, such as mortar or concrete containing cement.
      Retempering - Addition of water and remixing of concrete or mortar
which has started to stiffen.
      Rod Tamping (Rodding) - A round, straight, steel rod, having one end
rounded to a hemispherical tip.
      Sand Blast - A s ystem of cutting or abrading a surface, such as concret e
by a stream of sand ejected from a nozzle at high speed by compressed air;
often used for clean up of horizontal construction joints or for architectural
exposure of aggregate.
      Scaffolding - A temporar y structure for gaining access to higher levels of
the permanent structure during construction.




Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991         7/8




Scaling - Local flaking or peeling away of the near surface portion of hardened
concrete or mortar.

Scour- Erosion of a concrete surface, exposing the aggregate.

Segregation - The differential concentration of the components of mixed
concrete, aggregate, or the l ike, resulting in non uniform proportions in the
mass.
Separation - The tendenc y as concrete is caused to pass from the un -confined
ends of chutes or conveyor belts, or similar arrangements for coarse aggregates
to separate from the concrete and accumlulat e at one side; the tendenc y as
processed aggregate leaves the ends of conveyor belts, chutes, or similar
devices with confining sides, for the large aggregate to separate from the mass




                                                                                     217
TECHNICAL SPECIFICATION

and accumulate at one side; or the tendency for the solids to separate from the
water by gravitational settlement.
Set - The condition reached by a cement paste, mortar, or concrete when it has lost plasticity
to an arbitrary degree usually measured in form of resistance to penetration or deformation;
initial set refers to first stiffening; final set refers to attainment of significant rigidity.
Shotcrete (Pneumatically applied Mortar) - Mortar or concrete pneumatically
projected at high velocity into a surface; also known as air -blown mortar, also
pneumatically applied mortar or concrete, sprayed mortar and gunned concrete.

Shoulder- An unintentional offset in a formed concrete surface usually caused
by bulging or movement of form work.

Sieve Analysis - Determination of the proportions of particles lying within
certain size ranges in a granular material by separation on sieves of different
size openings.
Slipform (Moving or Sliding Form Work) - A form which moves, usually
continuously during placing of the concrete. Movement may be either horizontal
or vertical.
Slump - A measure of consistenc y of freshly mixed concrete, mortar, or stucco
equal to the subsidence measured to the nearest 6 mm of the moulded
truncated cone immediately after removal of the slump cone.
Slump Cone - A mould in the form of a truncated cone with a base diameter of
20 cm, top diameter 10 cm, and height 30 cm, used to fabricate a specimen of
freshly mixed concrete for the slump test.
Slump Test - The procedure for measuring slump.

Slurry - A mixture of water and any finely divided insoluble materials, such as
portland cement, slag or soil, in suspension.

Soundness - The freedom of a solid from cracks, flaws, fissures, or variations
from an accepted standard; in the case of cement, freedom from excessive
volume change after setting; in the case of aggregate, the ability to withstand
the aggressive action to which conc rete containing it might be exposed
particularly that due to weather.

Spacer - Device which maintains reinforcement in proper position, or wall forms
at a given distance apart before and during concreting.

Spall - A fragment, usually in the shape of a fl ake, detached from a large mass
by a blow, by the action of weather, by pressure, or by expansion within the
larger mass.

Specific Gravity - The ratio of the mass of a unit volume of a material at a
stated temperature to the mass of the same volume of a g as free distilled water
at a stated temperature.




Volume I –Sec..IV            Specifications For Irrigation Projects Nov. 1991              7/9




       Steam Curing - Curing of concrete or mortar in water vapour at
atmospheric or high pressures and at temperatures between 30 o and 215 o
centigrade.

       Subgrade - The soil prepared and compacted to support a structure or pavement
system.




                                                                                          218
TECHNICAL SPECIFICATION

      Surface Water - Free water retained on surfaces of aggregate particles
and considered to be part of the mixing water in concrete, as distinguished from
absorbed moisture.

       Swelling - Volume increase caused by wetting or chemical changes or
both; a function of times but not of temperature or of stress due to external load.

       Tamper - A hand operated device for compacting floor topping or other
unformed concrete by the impact caused by dropping it repeatedly from a small
height; in preparation for strike off and finishing; contact surface often consists
of open-mesh screen or a grid of bars to force coarse aggregates below the surface to
prevent interference with floating or trowelling.

        Tamping - The operation of compacting freshly placed concrete by
repeated blows.
        Temperature Cracking - Cracking due to tensile failure, caused by
temperature drop in members subjected to external restraints or temperature
differential in members subjected to internal restraints.
        Test Strength Sample - The test strength of the sample shall be the average of the
strength of three specimens. The individual variation should not be  15 percent of the
average.
        Texture - The pattern of configuration apparent in an exposed surface, as
of concrete or mortar, including roughness, streaking, striation, or departure
from flatness.
        Tolerance - The permitted variation from a given dimension or quantity.
        Tremie - A pipe or tube through which concrete is deposited under water,
having at its upper end a hopper for filling and a bail by means of which the
assembly can be handled by a derrick.
        Triaxial Compression Test - A test in which a specimen is subjected to
a confining hydrostatic pressure and then loaded axially to failure.
        Vibrator- An oscillating machine used to agitate fresh concrete so as to
eliminate gross voids, including entrapped air bu t not entrained air, and produce
intimate contact with form surfaces and embedded materials.
        Water Cement Ratio - The ratio of the amount of water, exclusive only of
that absorbed by the aggregates, to the amount of cement in a concrete or
mortar mixture; preferably stated as a decimal by weight.
        Wearing Course -       A topping or surface treatment to increase the
resistance of a concrete pavement or slab to abrasion.

      Weathering - Changes in colour, texture, strength, chemical composition
of other properties of a natural or artificial material due to the action of the
weather.

      Workability - That property of freshly mixed concrete or mortar which
determines the cause and homogeneity with which it can be mixed, placed,
compacted, and finished. It is the amount o f energy to overcome friction and
cause full consolidation.

       Yield - The volume of freshly mixed concrete produced from a known
quantity of ingredients; to total weight of ingredients divided by the net weight of
the freshly mixed concrete; also the number of product limit; such as block,
produced per bag of cement or per batch of concrete.

Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991          7/10



7.3 MATERIALS:


        7.3.1 Cement :




                                                                                      219
TECHNICAL SPECIFICATION

       7.3.1.1 Unless otherwise specified cement shall conform to the following
Indian Standard Specifications.


          (a)    Ordinar y portland cement 33 grade conforming to IS: 269 -1989

          (b)    Low heat portland cement conforming to IS: 12600 -1989.

          (c)    Rapid hardening portland cement conforming to IS: 8041 -1978.

          (d)    Portland slag cement conforming to IS: 455 -1976.

          (e)    Portland pozzolana cement conforming to IS: 1489 -1976.

          (f)    Ordinar y portland cement 43 grade conforming to IS: 8112 -1989.


       7.3.1.2 Precautions and Gu ide lines for use of Cement - The type of
cement to be used shall be specified by the Engineer -in-charge. Following guide
lines are given for use of different types of cement.


       (i) Low heat portland cement conforming to IS: 12600 -1989 shall be used
with adequate precautions with regard to removal of form work etc.


      (ii) High alumina cement conforming to IS: 6452 -1972 shall be used only
under special circumstances when directed by the Engineer -in-charge.


      (iii) Super sulphate cement conforming to IS: 6909 -1973 shall be used
only under special circumstances when directed by the Engineer -in-charge.
Option to use this type of cement should be taken with caution.


       (iv) The use of portland pozzolana cement is recommended as substitute
for ordinar y portland cem ent for plain and reinforced concrete work in general
building construction. In addition to 7 days compressive strength, IS: 1486 -
1976 specifies the minimum 28 days compressive strength of portland
pozzolana cement. However, for the reasons cited the rate of development of
early strength may be some what lower and concrete made with portland
pozzolana cement may need some what longer curing period under field
conditions, delayed removal of form work, etc. Portland pozzolana cement also
has the advantage of lower heat of hydration and better sulphate resistance.


       (v) Portland pozzolana cement is not allowed for RCC work of bridges
and prestress concrete. Portland slag cement to be used for prestress concrete,
the slag content should not be more than 50%.


      7.3.1.3 Stacking and Storage - Other specifications for cement such as
‘Supply”,”Stacking and Storage” shall be as described under para 7.3.1.2 of
Ch.6 “Mortars”.


       7.3.1.4 Test on Cement - The usual tests made on cement are fineness,
setting time, soundness, heat of hydration, compressive strength and chemical
composition. All physical and chemical composition tests are carried out in
accordance with the procedur es described in IS: 4031-1988 and IS: 4032-1985
and the results may be compared with standard as given in Appendix l for
guidance.


                                                                                  220
TECHNICAL SPECIFICATION



       The cement shall be tested also for adulteration. The frequencies of each
of these test shall be one per every 50 tonnes.


      The number of test specimen and the method of sampling shall be in
accordance with the specification for the type of cement being tested and IS:
3538-1986.


Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991                     7/11



7.3.2 Aggregate :


       7.3.2.1 General - Natural sands and gravels are by far the most common
and are used whenever they are of satisfactory quality and can be obtained
economically in sufficient quantity. Crushed r ock is widely used for coarse
aggregate and occassionally for sand when suitable material from natural
deposits are not economically available, although production of workable
concrete with sharp angular crushed fragments usually requires more vibration
and cement than that of concrete made with well rounded sand and gravel. It
shall consist of coarse aggregates most of which are retained on 4.75 mm IS
Sieve, but the actual size shall be in accordance with the provisions of the
following clauses.


      7.3.2.2 Quality of Aggregate - Aggregates shall consist of naturall y
occuring (crushed or uncrushed) stone, gravels and sand or combination
thereof. Aggregates shall be hard, strong, dense, durable, clean and free from
veins and adherent coating, and free from in jurious amounts of disintegrated
pieces, alkali, vegetable, matter and other deleterious substances. As far as
possible, flak y, scoriaceous and elongated pieces should be avoided.


       7.3.2.3 Deleterious materials - Aggregates shall not contain any harmful
materials such as pyrites, coal, lignite, mica, shale or similar laminated
material, clay, alkali, soft fragments, sea shells and organic impurities in such
quantity as to affect the strength or durability of the concrete. Aggregates to be
used for reinforced concrete shall not contain any material liable to attack the
steel reinforcement. Aggregates which are chemically reactive with alkalies of
cement are harmful as cracking of concrete may take place.
       The maximum quantity of deleterious materials shall not exceed the limits
specified in table l as given below, when tested in accordance with IS: 2386 -
1977. However the Engineer-in-charge at his discretion, may relax some of the
limits as a result of some further tests and evidence of satisfactory performance
of the aggregates.

                                        TABLE - I
                           Limits of Deleterious Materials
                                      (Para 7.3.2.3)


Sl.   Deleterious           Method            Fine aggregate                          Coarse      aggregate
No.   Substance             of test           percentage by                  percentage by
                                              weight, maximum                weight, maximum
                                             Uncrushed      Crushed          Uncrushed Crushed



                                                                                               221
TECHNICAL SPECIFICATION



1.          2.                           3.                4.                5.        6.      7.


 i)    Coal and lignite.              IS:2386               1.00             1.00      1.00   1.00
                                      (Pt.II) 1977

 ii)   Clay lumps.                    -do-                  1.00             1.00      1.00   1.00
iii)   Materials finer than.          IS:2386               3.00             15.00     3.00   3.00
       75-micron IS Sieve.            (Pt.I) 1977


iv)    Soft fragments.                IS:2386                   -                 -    3.00     -
                                      (Pt.II) 1977
v)     Shale.                            -do-               1.00                  -     -       -

vi)    Total percentage of                -                 5.00             2.00      5.00   5.00
       all deleterious materials
       (except mica) including
       Sl.No. (i) to (v) for Col.
       4,6 and 7 and Sl.No. (i) and
       (ii) for Col.5 only.


Volume I –Sec..IV                   Specifications For Irrigation Projects Nov. 1991           7/12



       Note 1 - The presence of mica in the fine aggregate has been found to reduce
                considerably the durability and compressive strength of concrete and further
                investigations are under way to determine the extent of the deleterious effect
                of mica. It is advisable, therefore, to investigate the mica content of fine
                aggregate and make suitable allowances for the possible reduction in the
                strength of concrete or mortar.


       Note 2 - The aggregate shall not contain harmful organic impurities (tested in
                accordance with IS: 2386 ( Part ll - 1977) in sufficient quantities to affect
                adversely the strength or durability of concrete. A fine aggregate which fails in
                the test for organic impurities may be used ; provided that, when tested for
                the effect of organic impurities on the strength of mortar, the relative strength
                at 7 and 28 days, reported in accordance with para 7 of IS: 2386 (Part VI) -
                1977 is not less than 95 percent.


      7.3.2.4 Mechanical and Physical Properties - Mechanical and Physical
properties shall be as described in table 2 below : -
                                                   TABLE - 2
                               Mechanical and Physical Properties


                                                Specified limits of result




                                                                                              222
TECHNICAL SPECIFICATION

S.No.     Test result                  Concrete other than        Concrete for
                                       wearing surfaces           wearing surfaces


(1)             (2)                           (3)                        (4)

1.        Crushing value.              shall not exceed 45%       shall not exceed 30%
2.        Ten percent fines value.     shall not be less than     shall not be less than
                                       5 tonnes                   10 tonnes

3.        Impact value by weight.      shall not exceed 45%       shall not exceed 30%
4.        Abrasion value by            shall not exceed 50%       shall not exceed 30%
          losangles machine.

5.        Flakiness Index.             Not greater than 25%       As per col.3


       Soundness of Aggregate - For concrete liable to be exposed to the
actions of frost, coarse and fine aggregates shall pass a sodium or magnesium
sulphate accelerated soundness test specified in IS: 2386(PartV) -1977, the
limits being set by agreement betwee n the purchaser and supplier, except that
aggregates failing in the accelerated soundness test may be used if they pass a
specified freezing and thawing test as described in IS: 2386 (Pt -V)-1977,
satisfactory to the user.


        As a general quide it may be tak en that the average loss of weight after
5 c ycles shall not exceed the following: -


          (a)     For fine aggregate     ... 10 percent when tested with sodium
                                             sulphate (Na 2 SO 4 ) and 15 percent when
                                            tested with magnesium sulphate (MgSO 4 ).


          (b)     For coarse aggregate ...   12 percent when tested with sodium
                                         sulphate (Na 2 SO 4 ), and 18 percent when
                                            tested with magnesium sulphate (MgSO 4 ).




                                                                                     223
TECHNICAL SPECIFICATION




Volume I –Sec..IV                                                       Specifications For Irrigation Projects Nov. 1991                      7/13



                                                                                    Table - 3


IS sieve            Percentage passing for single-sized aggregate                           Percentage passing for graded

                                 of nominal size                                                      aggregate


Designation         63mm           40mm            20mm        16mm       12.5mm 10mm                   40mm               20mm     16mm        12.5mm

1                   2               3              4            5           6           7                 8                9         10                11


80mm                100             ...            ...          ...        ...         ...              100                ...       ...         ...



63mm          85to 100             100             ...          ...        ...         ...               ...               ...       ...         ...



40mm           0 to 30          85 to 100          100          ...        ...         ...           95 to 100             100       ...         ...



20mm            0 to 5            0 to 20      85 to 100       100         ...         ...            30 to 70         95 to 10     100          ...



16 mm               ...             ...            ...      85 to 100     100          ...               ...               ...    90 to 100      ...



12.5mm              ...             ...            ...          ...     85 to 100     100                ...               ...       ...   90 to 100




                                                                                                                                                            224
TECHNICAL SPECIFICATION




10 mm           0 to 5    0 to 5   0 to 20   0 to 30   0 to 45 85 to 100   10 to 35   25 to 55   30 to 70 40 to 85



4.75mm            ...       ...    0 to 5    0 to 5    0 to 10   0 to 20    0 to 5    0 to 10    0 to 10   0 to 5

2.36mm            ...       ...      ...       ...       ...     0 to 5       ...        ...        ...      ...




                                                                                                                     225
TECHNICAL SPECIFICATION


Volume I –Sec..IV          Specifications For Irrigation Projects Nov. 1991                       7/14



.3.2.5 Size and Grading of Aggregates :


       7.3.2.5.1 Size and Grading of Coarse Aggregate - Nominal maximum size of
coarse aggregate shall be as specified in approved drawing of work. For any one of the
nominal sizes, the proportion of other sizes shall be in accordance with table 4. Graded
coarse aggregate may be used in the nominal sizes of 40 sizes shall be in accordance
with table 4. Graded coarse aggregate may be used in the nominal sizes 40 mm, 20 mm,
16 mm, 12.5 mm. Grading of graded coarse aggregate shall be also in accordance with
table 3.


      For any one of the nominal sizes of coarse aggregate for mass concrete works, the
proportions of other sizes shall be as specified in table 4.


                                               TABLE - 4
                          Sizes of Coarse Aggregate for Mass Concrete


Class and size                           IS Sieve designation                 Percentage passing


       1.                                       2.                                           3.


       Very large 120 to 80 mm.                 160m*                              90 to 100
                                                80 mm                             0 to 100


       Large, 80 to 40 mm.                      80 mm                             90 to 100
                                                40 mm                             0 to 10


       Medium, 40 to 20 mm.                     40 mm                             90to100
                                                20 mm                             0to 10


       Small 20 to 4.75 mm.                     20 mm                             90 to 10
                                                4.75 mm                           0 to 10
                                                2.36 m                            0 to 2


      * There being no IS Sieve having an aperture larger than 100 mm a p erforated plate
complying with IS : 2405-1980 and having a square aperture of 160 mm may be used .




                                                                                                         226
TECHNICAL SPECIFICATION



      However, if nominal maximum size of aggregate is not specified in drawing, it may
be adopted with the permission of Engineer-in-charge on basis of some guidelines given below :-


7.3.2.5.2 Guide Lines -


       (i) The nominal maximum size of aggregate shall be as large as possible within the
limits specified but in no case greater than one -fourth of the minimum thickness of the
member, provided that the concrete can be placed without difficulty so as to surround all
reinforcement thoroughly and filling corners of the form. For reinforced concrete work,
aggregates having nominal size of 20 mm are generally considered satisfactory.


       (ii) For heavily reinforced concrete members as in case of ribs of main beams, the
nominal maximum size of the aggregate should usually be restricted to 5 mm less than the
minimum clear distance between the main bars or 5 mm less than the minimum cover to
the reinforcement whichever is smaller. W here the reinforcement is widely spaced as in
solid slabs, limitations of the size may sometimes be as great as, or greater than the
minimum cover.




Volume I –Sec..IV               Specifications For Irrigation Projects Nov. 1991                      7/15


      (iii) Following maximum nomina size of aggregate for different size of section and
zone are given in table 5&6.


                                                    TABLE - 5

            Maximum Size of Aggregate Recommended for Various Types of Construction.

                                                     Maximum size of aggregate (mm)

Minimum              Non rein-           R.C. walls,            Lightly reinforced         Heavily
dimensions of        forced walls        beams and              or non reinforced          reinforced
section (mm)                             columns.               slabs.                     slabs.

(1)                       (2)               (3)                        (4)                      (5)

65 to 130                 20             12 to 20               20 to 40                   20 to 30
150 to 280                40             20 to 40               40 to 75                   40
305 to 740                80             40 to 75               75                         40 to 75
750 to above         160                 75 to 150              75 to 150                  40 to 75


                                                    TABLE - 6

                      Maximum Size of Aggregate for Dam and Appurtenant Works

S.No.                           Location of use                                      Maximum aggregate



                                                                                                             227
TECHNICAL SPECIFICATION


                                                                                    size in mm
(1)                                     (2)                                             (3)

1.            Filling Crevices in foundation of non over
              flow and over flow section.                                             ... 40

2.            Spillway and training wall sections (except
              exterior thicknessshown in drawing).                                    ... 75

3.            Spillway crest, glacis, u/s face of spillway bucket,
              divide wall and water face of training wall (60 cm).                    ... 75

4.            All around galleries, adits, sump well, pump
              chamber, contraction joint and other openings.                          ... 40

5.            Sandwich concrete.                                                      ... 75
6.            Deck bridge.                                                            ... 20
7.            Top 60 cm of bucket.                                                    ... 40
8.            Bucket teeth.                                                           ... 20
9.            Block out concrete for embeded parts of gates,
              elevators, instrumentations, etc.                                       ... 20

10.           Foundations for divide/training wall.                                   ... 75
11.           R.C.C. Well curb, steining and piles.                                   ... 40
12.           P.C.C. well steining.                                                   ... 63
13.           Well cap of pile, solid type piers, abutments
              & wing walls & their pier caps.                                         ... 40
14.           R.C.C. bearings.                                                        ... 20



Volume I –Sec..IV                Specifications For Irrigation Projects Nov. 1991                7/16



       7.3.2.5.3 Size and Grading of Fine Aggregate (Sand) - The grading of fine
aggregate shall be within the limits giv en in table 7 and shall be described as fine
aggregate, grading zone l, ll, lll, lV. W here the grading falls out side the limits of any
particular zone of sieves other than 600 micron IS Sieve by a total amount not exceeding
5%, it shall be regarded as fal ling within that grading zone. This tolerence shall not be
applied to percentage passing the 600 micron IS Sieve or to percentage passing an y
other sieve size on the coarse limit of grading Zone l or the finer limit of grading Zone lV.

      Very fine sands as included in Zone lV grading should not be used except when the
concrete is closely controlled.
                                        TABLE - 7
                                      Fine Aggregate

                                                    Percentage passing for

       IS Sieve                    Grading                Grading               Grading          Grading
       Designation                 Zone-I                 Zone-II               Zone-III         Zone-IV




                                                                                                           228
TECHNICAL SPECIFICATION



       10   mm.             100                   100                        100       100
       4.75 mm.             90-100                 90-100                95-100        90-100
       2.36 mm.             60-95                  75-100                85-100        95-100
       1.18 mm.             30-70                  55-90                 75-100        90-100
       600 Micron.            5-20                  8-30                 12-40         15-50    150 Micron.
                              0-10                  0-10                     0-10       0-15

      Note 1 :- For crushed stone sands, the permissible limit on 150 ‘micron’ IS Sieve is
increased to 20 percent. This does not affect the 5 percent allowance permitted under
para 7.3.2.5.3 applying to other sieve sizes.

       Note 2 :- Fine aggregate complying with the requirements of any grading zone in
the tables is suitable for concrete but the quality of concrete produced will depend upon a
number of factors including proportions.

       Note 3 :- W here concrete of high strength and good durability is required, fine
aggregate conforming at any one of the four grading zones may be used, but the concrete
mix should be properly designed. As the fine aggregate grading becomes progressively
finer, that is, from Grading Zones l to lV, the ratio of fine aggregate should be
progressively reduced. The most suitable fine to coarse ratio to be used for any particular
mix will, however, depend upon the actual grading, particle shape and surface texture of
both the fine and coarse aggregates.

       Note 4 :- It is recommended that fine aggregate conforming to Grading Zone lV
should not be used in reinforced concrete unless tests have been made to ascertain the
suitability of proposed Mix proportions.

       7.3.2.5.4 All-in-aggregates - “All in Aggregate” are generally not found suitable for
making concrete of high quality. It shall be used only where specifically permitted by the
Engineer-in-charge. If combined aggregate are available they need not be separated into
the fine and coarse, but necessary adjustments may be made in the grading by the
addition of single sized aggregates. The grading of the “all -in-aggregate” shall be in
accordance with table 8.




Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991             7/17



                                             TABLE - 8
                                     All-in Aggregate Grading

         IS Sieve                     Percentage passing for All-in-Aggregate of

                                     40 mm Nominal size            20mm Nominal size

       80   mm                             100                           ...
       40   mm                             95 to 100                     100
       20   mm                             45 to 75                      95 to 100



                                                                                                229
TECHNICAL SPECIFICATION



       4.75 mm                                      25 to 45                    30 to 50
       600 micron                                    8 to 30                    10 to 35
       150 micron                                    0 to 6                         0 to 6

      7.3.2.6 Bulking of Sand - In volume batching, sand is assumed to be dry. Dry and
saturated sands have almost the same volume, but da mp sand increases in volume.
Bulking depends primarily upon moisture content and marginally on grading of sand. Due
allowance for bulking of sand shall be made, while preparing the concrete mixes based on
volume measurement.

       The bulking allowance of any sample of sand shall be determined in accordance
with procedure given in Appendix ll.

       7.3.2.7 Handling and Storage - Aggregates shall be stored on a clean hard surface
and maintained free from loam and vegetable matter and exposure to dust or any other
contamination. Aggregates of different types and sizes shall be stored in separate heaps
to avoid mixing up. On a large job it is desirable to construct dividing walls to give each
type of aggregate its own compartment. Fine aggregates shall be stacked in a place where
loss due to the effect of wind is minimum. The aggregates shall be handled in such a
manner as to minimise the breakage of particles. Unless specified otherwise or
necessitated by site conditions, stacking of the aggregate should be carried out in regular
stacks. The suggested sizes for stacks are given in table 9.

                                                       Table - 9

          S No.           Material                                 Size of stack (in metres)
                                                    Length               Breadth             Height

            (i)      Solling stone                   5.0                       2.0            0.50
                                              or,    5.0                       1.0            0.50
            (ii)     Coarse aggregate                2.0                       2.0            0.50
                                              or,    5.0                       5.0            1.00
                                              or,    5.0                       1.0            0.50


            (iii)    Fine aggregate                  2.0                       2.0            0.50
                                              or,    5.0                       5.0            1.00
                                              or,    5.0                       1.0            0.50




Volume I –Sec..IV                Specifications For Irrigation Projects Nov. 1991                     7/18



       7.3.2.8 Sampling and Testing - Samples of aggregates for use on a particular
major work shall be sent to the laboratory at least 35 days before commencement for use
in the works and used only after obtaining the approval.



                                                                                                             230
TECHNICAL SPECIFICATION


      If during the course of work the source or type of any material be changed the
samples shall be tested and used only after approval by the competent authority.

       The method of sampling shall be in accordance with IS: 2430 -1986 and tests shall
be carried out as described in IS: 2386 -1977.
       7.3.3 Plums :
       7.3.3.1 All plums shall be hard, durable, clean and free from soft materials or loose
pieces or deleterious substances embedded in them and shall not have sharp corners. The
plums shall be free from adhering films or coatings and the crushing value of plums shall
not be less than that specified for coarse aggregate.
       7.3.3.2 Size of Plums - In mass concrete members, stone plums from 150 mm to
300 mm size may be used. The maximum dimensions of these stones or plums shall not
exceed 1/3rd the least dimension of the member.
       7.3.3.3 Storage - Materials shall be so stored as to prevent their deterioration on
infusion of foreign matter and to ensure the preservation of their quality and fitness for the work.
       7.3.4 Water- W ater used for mixing and curing shall be clean and free from
injurious amounts of oils, acids, alkalis, salts, sugar, organic materials or other
substances that may be deleterious to concrete or steel. Potable water (the exception
being water containing sugar) is generally considered satisfactory for mixing concret e. As
a guide the following concentrations represent the maximum permissible values.

      (a) To neutralize 200 ml sample of water using phenolphthalein as an indicator, it
should not require more than 2 ml of 0.1 normal NaOH.

      (b) To neutralize 200 ml sample of water using methyl orange as an indicator, it
should not require more than 10 ml of 0.1 normal HCl.

      (c) Percentage of some impurities and solids shall not exceed the limits given in
Table 10 and 11 respectively.

       7.3.4.1 In case of doubt regarding dev elopment of strength, the suitability of water
for making concrete shall be ascertained by the compressive strength and initial setting
time tests specified in 7.3.4.1.2 and 7.3.4.1.3.

       7.3.4.1.1 The sample of water taken for testing shall represent the wa ter proposed
to be used for concreting, due account being paid to seasonal variation. The sample shall
not receive any treatment before testing other than that envisaged in the regular supply of
water proposed for use in concrete. The sample shall be stor ed in a clean container
previously rinsed out with similar water.
       7.3.4.1.2 Average 28 days compressive strength of at least three 15 cm concrete
cubes prepared with water proposed to be used shall not be less than 90 percent of the
average strength of three similar concrete cubes prepared with distilled water. The cubes
shall be prepared, cured and tested in accordance with the requirement of IS: 516 -1959.

      7.3.4.1.3 The initial setting time of test block made with the appropriate cement and
the water proposed to be used shall not be less than 30 minutes and shall not differ by ±
30 minutes from the initial setting time of control test blocks prepared with the same
cement and distilled water. The test blocks shall be prepared and tested in accordance
with the requirements of IS: 4031 -1988.


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        7.3.4.2 The PH value of water shall generally be not less than 6.




                                                                                                231
TECHNICAL SPECIFICATION




                                                TABLE - 10

        Concentration of some Impurities in Mixing Water which can be considered as tolerable


S.No.              Impurity                                       Maximum tolerable Concentration


1)         Sodium and potassium carbonates          ...           1000 ppm (total) (if this is exceeded

           and bicarbonates.                                      tests for setting time and 28 days

                                                                  strength should be made).

2)         Sodium chloride.                         ...           20,000 ppm.

3)         Sodium sulphate.                         ...           10,000 ppm.
4)         Calcium and Magnesium                    ...           400 ppm of bicarbonate Ion.
           bicarbonates.

5)         Calcium chloride.                        ...           2 percent by weight of cement in

                                                                  plain concrete.

6)         Iron salts.                              ...           40,000 ppm.

7)         Sodium iodate, phosphats,                ...           500 ppm.

           arsenate and berate.

8)         Sodium sulphide.                         ...           Even 100 ppm warrants testing.

9)         Hydrochloric and sulphuric and           ...           10,000 ppm.

           other common inorganic acids.

10)        Sodium hydroxide.                        ...           0.5 percent by weight of cement

                                                                  if set not affected.

11)        Silt and suspended particles.            ...           2,000 ppm.




                                                TABLE - 11
                                  Permissible Limit for Solids (Para 7.3.4)


                  Solids                            Permissible Limit, Max
                                                           mg/1

                  Organic.                                 200

                  Inorganic.                               30,000



                                                                                                          232
TECHNICAL SPECIFICATION



                    Sulphates (as SO).                            500

                    Chlorides (as Cl).                            2,000 for plain concrete work, &

                                                                  1,000 for reinforced concrete work

                    Suspended matter.                             2,000


       7.3.4.3 Storage of Water - W here water is to be stored for construction purposes
this shall be done in proper storage tanks to prevent any organic impurities getting mixed up with it.


        7.3.5 Admixtures :


      7.3.5.1 Admixtures may be used with the approval of the Engineer -in-charge for
special purpose or for imparting special characteristics to the concrete on satisfactory
evidence that the use of such admixtures does not adversely affect the properties of
concrete particularly




Volume I –Sec..IV                 Specifications For Irrigation Projects Nov. 1991                   7/20



 with respect to strength, volumes change, durability and has no deleterious effect on
reinforcement and wherever so permitted the correct proportion and the method of use
shall be as fixed by laborator y. The admixture shall conform to IS: 9103 -1979.


       Materials permitted as admixtures shall have established merit for any of the
following purpose:-


          (i)       Improvement of workability.

          (ii)      Reduction of heat evolution.

          (iii)     Decrease in permeability.

          (iv)      Increase in durability.

          (v)       Accelerating of hardening, setting or strength.

          (vi)      Increase in unit weight.

          (vii) Retardation of setting time.

          (viii) Increase in shear and bond.




                                                                                                            233
TECHNICAL SPECIFICATION


      7.3.5.2 Before using an admixture in concre te its performance should be evaluated
by comparing the properties of concrete with the admixtures and concrete without any
admixture. The chloride content of the admixtures shall be declared by the manufacturers.
The physical requirements of an admixture shall be as per Appendix - lll.


       7.3.5.3 Informations on Admixture - To facilitate approval of an admixture the
following information is needed: -


     (a)   The trade name of the admixture, its source, and the manufacturer’s
recommended method of use;


     (b)            Typical dosage rates and possible detrimental effects of under and over
dosage;


       (c)     W hether compounds, likely to cause corrosion of reinforcement or
deterioration of concrete(such as those containing chloride in any form as in active
ingredient) are present and if so, the chloride ions by mass or expressed as equivalent
anhydrous calcium chloride by mass of admixtures; and


      (d)   The average expected air content of freshly mixed concrete containing an
admixture which causes air to be entrained when used at the manufacturer’s
recommended rate of dosage.


       7.3.6 Pozzolana - Pozzolanic materials conforming to relevant Indian Standards
may be used with permission of the Engineer -in-charge. Calcined pozzolana shall conform
to IS:1344-1981.


       7.3.7 Fly Ash - Fly ash may be used as an admixture or part replacement of fine
aggregate or unblended cements(provided uniform blending with the cement is ensured)
with the permission of Engineer -in-charge. Fly ash shall conform to IS: 3812 -1981.


       7.3.8 Reinforcement - Quality and other specifications of reinforcement shall be as
laid down under Ch. 13 “Steel and Iron W ork”.


        7.4 GRADE OF CONCRETE AND TYPE OF MIX :
       7.4.1 General - :Concrete is composed of sand, gravel, crushed rock, or other
aggregates held together by a hardened paste of hydraulic cement and water. The
thoroughly mixed ingredients, when properly proportioned, make a plastic mass which can
be cast or moulded into a predetermined size and shape. Upon hydration of the cement
by the water
Volume I –Sec..IV             Specifications For Irrigation Projects Nov. 1991   7/21



concrete becomes stone like in strength and hardness, and has utility for many purposes.




                                                                                        234
TECHNICAL SPECIFICATION


        7.4.2 Grade of Concrete - The concrete shall be in grades designated as per Table 12.


                                              TABLE - 12
                                           Grade of Concrete


                     Grade                              Specified characteristic Comp-
                     designation                        ressive Strength at 28 days

                                                               (N/mm2)


                     M5              ...                            5

                     M 7.5           ...                            7.5

                     M 10            ...                            10

                     M 15            ...                            15

                     M 20            ...                            20

                     M 25            ...                            25

                     M 30            ...                            30

                     M 35            ...                            35

                     M 40            ...                            40


        Note 1 :- In the designation of a concrete mix, letter M refers to the mix and the
                  number to the specified characteristics compressive strength of 15 cm
                  cube at 28 days, expressed in N/mm 2 .


        Note 2 :- M 5 and M 7.5 grades of concrete may be used for lean concrete bases
                  and simple foundations for masonry walls. These mixes need not be
                  designed.


        Note 3 :- Grades of concrete lower than M 15 shall not be used in reinforced
                  concrete.


        Note 4 :- Grades of concrete lower than M 30 shall not be used in past -tensioned
                  prestressed concrete & M 40 for pretensioned pre -stressed concrete.


      7.4.3 Classification of Concrete - Concrete can be classified either as “Nominal
Mix Concrete” or “Designed Mix Concrete” as specified below:-


          Designed Mix - W here the mix proportions are fixed by designing the concrete
                       mixes is called “Designed Mix”.



                                                                                                235
TECHNICAL SPECIFICATION




          Nominal Mix - W here nominal concrete mix is adopted, such concrete shall be
                       called “Nominal Concrete Mixes”.


7.5 CONCRETE MIX PROPORTIONING :
        7.5.1 Mix Proportion - The mix proportions shall be selected to ensure that the
workability of the fresh concrete is suitable for the conditions of handling and placing, so
that after compaction it surrounds all reinforcements and comple tely fills the formwork.
W hen concrete is hardened, it shall have the required strength, durability and surface
finish.
        7.5.2 Determination of Proportions :


       7.5.2.1 The detremination of proportions of cement, aggregates and water to attain
the required strengths shall be made as follow: -

          (a)       By designing the concrete mix.

          (b)       By adopting nominal concrete mix.
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       Design mix concrete is preferred to Nominal mix. The Nominal mix concrete should
be restricted to works of minor nature in which the strength of concrete is not critical. If
design mix concrete cannot be used for any reason on the work for grades of M 20 or
lower, nominal mixes may be used with the permission of Engineer -in-charge.


       7.5.2.2 Information required - In specif ying a particular grade of concrete, the
following information shall be included.


          (a)       Type of Mix, that is, design mix concrete or nominal mi x concrete;

          (b)       Grade designation as specified in tabel 12;

          (c)       Type of cement;

          (d)       Maximum nominal size of aggregate;

          (e)       Minimum cement content (for design mix concrete);

          (f)       Maximum water cement ratio;

          (g)       W orkability ; and

          (h)       Mix proposition (f or nominal mix concrete).


        In appropriate circumstances, the following additional information may be specified.


          (a)       Type of aggregate;
          (b)       Maximum cement content; and



                                                                                            236
TECHNICAL SPECIFICATION



           (c)      W hether an admixture shall or shall not be used and the type of admixtures
                    and the conditions of use.


       7.5.2.3 Design Mix Proportioning - The mix shall be designed to produce the
grade of concrete having the required workability and a characteristic strength not less
than the appropriate values given in Table 12.


      As long as the quality of the materials does not change, a mix design done earlier
may be considered adequate for later work.


        7.5.2.4 Nominal Mix Proportioning:


       7.5.2.4.1 Nominal Mix by weights - The proportions of materials for nominal mix
shall be as given in Table 13 on the basis of weight of cement and aggregates.


                                                      TABLE - 13
                                     Proportions for Nominal Mix Concrete


Grade of              Total quantity of dry aggregates         Proportion of                Quantity of
concrete              by Mass per 50 kg of cement, to         fine aggregate to             water per
                      be taken as the sum of the              coarse aggregate              50 kg of
                      individual masses of fine and           (By Mass)                     cement (Max)
                      coarse aggregates (Max).                                                 Litre)
                              (Kg)
   1                             2                                   3                        4



   M5                            800                                 Generally 1:2            60

   M 7.5                         625                                 but subject to an        45

   M 10                          480                                 upper limit of 1:1.5     34

   M 15                          350                                 and a lower limit if     32

   M 20                          250                                 1:2.5                    30




Volume I –Sec..IV                Specifications For Irrigation Projects Nov. 1991                       7/23




                                                                                                               237
TECHNICAL SPECIFICATION


       Note - The proportions of the fine to coarse aggregate should be adjusted from
upper limit to lower limit progressively as the grading of the fine aggregates becomes finer
and the maximum size of coarse aggregate becomes larger. Graded coarse aggregate
shall be used.


      Example - For an average grading of fine aggregate (that is, zone ll of Table 6 the
proportions shall be 1:1-1/2, 1:2 and 1:2-1/2 for maximum size of aggregate 10 mm, 20
mm and 40 mm respectively.


      7.5.2.4.2 Nominal Mix Concrete by Volume - Nominal mix proportion by volume
under special circumstances, may be permitted by Engineer -in-charge. A rough guide for
the nominal mix proportions by volume will be 1:4:8, 1:3:6, 1:2:4 and 1:1/2:3 for M 7.5m M
10, M 15 and M 20 concrete respectively.


       For cement which normally comes in bags and is used by weight, volumes shall be
worked out taking 50 kg of cement as 0.035 cu.m in volume. The quantity of water per 50
kg (0.035 cu.m) of cement shall be as specified in Table 13.
       7.5.2.4.3 Limitations of Nominal Mix P roportions - The nominal mix proportions
in para 7.5.2.4.1 and 7.5.2.4.2 shall be valid, provided that: -


       (i)    Nominal maximum size of aggregate is 20 mm. For other sizes of
aggregates, adjustments in the ratio of the weight/volume of coarse and fine aggre gates
will be necessar y as indicated in the note below Table 13.


       (ii)   The aggregate to be used shall be dry, if not, corrections for bulking of sand
(is required only in case of nominal mix by volume) and surface water of aggregate shall
apply.


      (iii)  In all cases of nominal mix, fine aggregates shall conform to the grading of
Zone ll or Zone lll as described in Table 7 of para 7.3.2.5.2. “:Size and Grading of Fine
Aggregate”.


        7.5.2.4.4 Guide lines for Nominal Mix Proportioning :


       (1) The cement content of the mix specified in Table 13 for any nominal mix shall be
proportionately increased if the quantity of water in a mix has to be increased to overcome
the difficulties of placement and compaction, so that the water cement ratio as specified is
not exceeded.
       In case of vibrated concrete, the limit of quantity of water specified in Table 13 ma y
be suitably reduced to avoid segregation.
      (2) Allowance for bulking of sand is necessary only in case of volume batching as
described in para 7.3.2.6. However, al lowance for surface water carried by aggregate
should be made in all cases.




                                                                                          238
TECHNICAL SPECIFICATION


      In the absence of exact data, only in the case of nominal mixes, the amount of
surface water may be estimated from the values given in Table 14.


                                                     TABLE - 14
                                     Surface Water carried by Aggregate


              Aggregate                                 Approximate quantity of surface water
                                              Percent by Mass                       Litre/cu.m


       Very wet sand.                             7.5                                  120
       Moderately wet sand.                       5.00                                 80
       Moist sand.                                2.5                                  40
       *Moist gravel or crushed rock.             1.25 to 2.5                          20 to 40

                          *Coarser the aggregate, less the water it will carry.


Volume I –Sec..IV                Specifications For Irrigation Projects Nov. 1991                 7/24



        (3) If nominal mix concrete made in accordance with the proportions given for
particular grade does not yield the specified strength, such concrete shall be classified as
belonging to the appropriate lower grade. Nominal mix concrete proportioned for given
grade in accordance with Table 13. It shall not, however, be placed in higher grade on the
ground that the test strength is higher than the minimum specified.
7.6 QUALITY OF CONCRETE:
       7.6.1 General - After materials have been selected and relative proportio ns
determined, its use should be controlled to best advantage. Purpose of field control
involves correct procedures of proportioning, mixing, handling, placing and curing. Field
control governs quality, uniformity and ultimate econom y of the structure. Much potential
value of first class materials and optimum proportioning may be lost through ineffective
control of these procedures. The poorer the quality of the ingredients, the need for rigid
control to attain satisfactory durability and strength and there fore, maximum serviceable
life.
       7.6.2 Field Control - The quality of all concrete shall be stictly controlled through out the job. The
optimum proportion of all ingredients will be determined through extensive laboratory tests of concrete
made from the type of cement and kind of aggregates proposed for the work.
      In case of specified nominal mix, the proportion of ingredients shall be as described
under para 7.5.2.4 “Nominal Mix Proportioning”.
       The preliminar y tests shall be completed well before the begining of concreting
operations and a complete report on the concrete forming qualities and suitablility of
available aggregates as also recommendations for their use at the work shall be made and
approved by the Engineer-in-charge before actual concreti ng is started.
      No substitution in the materials used on the work or alterations in the established
proportions (except correction made for bulking of sand incase of volume batching and
moisture content on surface of aggregate) shall be made unless addition al tests have




                                                                                                         239
TECHNICAL SPECIFICATION


been conducted to show that the quality and strengths of the resulting concrete are
satisfactory.
       The Engineer-in-charge may carry out check tests and order changes in the mix as
may be necessar y from time to time to maintain the specified qu ality of the work. No
radical changes, substitutions and additions in the mix, shall be made without such check
tests and subsequent approval.


      Workability - From the stage of mixing till it is transported, placed in the form work
and compacted, fresh conc rete should satisfy a number of requirements as mentioned
below:-


          (a)       The mix should be stable, in that it should not segregate during
                    transportation and placing. The tendenc y of bleeding should be minimized.


          (b)       The mix should be cohesive and mobile e nough to be placed in the form
                    work around the reinforcement and should be able to cast into the required
                    shape.
          (c)       The mix should be amenable to proper and thorough compaction as possible
                    in the situation of placing and with the facilities of compaction .
          (d)       It should be possible to obtain a satisfactory surface finish.


       The above requirements of stability, mobility, compactibility, placeability, and
finishability of fresh concrete mentioned above are collectively referred to as “workability”.
Optimum workability of concrete varies from situation to situation and concrete which can
be termed as workable for pouring into large sections with minimum reinforcement may not
be equally workable for pouring in thin section with heavier concentration of
reinforcement. A concrete may not be workable when compacted by hand but may be
satisfactory when mechanical vibration is used.


Volume I –Sec..IV               Specifications For Irrigation Projects Nov. 1991     7/25



     7.6.3.1 Measures for Workability - There are following three methods for
measuring the workability.


          (a) Slump test.          (b) Compacting factor test. (c) Vee -Bee consistency test.


       Slump Test- This test is most widely used, primarily because of the sim plicity of the
apparatus required and the test procedure. Slump test is essentially a measure of
‘consistenc y’ or ‘witness’ of the mix. This test is suitable for concretes of medium to high
workability i.e. slump 25 to 125 mm. For very stiff mixes having zero slump, the slump test
does not indicate any difference in concretes of different workabilities.


      (b) Compacting Factor Test - It is the ratio of the weight of partially compacted
concrete to the weight of fully compacted concrete. This test is more a ccurate than slump




                                                                                                240
TECHNICAL SPECIFICATION


test and it is suitable for concrete mixes of medium and low workability that is compacting
factor of 0.9 to 0.8. This test is conducted as per procedure laid down in IS: 1199 -1959.


       (c) Vee-Bee Test - This test is conducted with the Vee-Bee apparatus and is measured in terms
of time of vibrations in seconds, required to transform the concrete sample from a truncated cone
(remaining after removal of the cone) into a right cylinder; the time is assumed directly proportional to the
energy used in compacting sample. This test is preferred for stiff concrete mixes having low or very low
workability. Detailed procedure of this test is given in IS: 1199-1959.


       7.6.3.3 The choice of workability depends upon the type of compacting equipment
available, the size of the section of concentration of reinforcement. For heavily reinforced
sections or when the sections are narrow or contain in -accessable parts or when the
spacing of reinforcement makes placing and compaction diffucult, concrete should be
highly workable for full compaction to be achieved with a reasonable amount of effort. The
Table 15 gives ranges of workabilities required in term of slump, compacting factor and
Vee-Bee time for concrete depending upon placing conditions at site. The nom inal
maximum size of aggregates makes a difference in degree of workability that may be
suitable under a particular placing condition. The values in the table are only a guide not
withstanding the situation at hand and should be properly assessed to arrive at the
desired workability in each case. Insufficient workability resulting in incomplete
compaction may severely affect the strength, durability and surface finish of concrete and
be uneconomical in the long run. The effectiveness of vibration equipment available
should also be assessed.
     However, for guidance suggested ranges of values of workability of concrete to
some placing conditions, measured in accordance with IS: 1199 -1959 are given below :-


                                                    TABLE - 15
  Placing conditions                                 Degree of                 Value of Workability
                                                     Workability
        (1)                                              (2)                           (3)
Concreting of shallow sections with                  Very low       20-10 seconds, Vee-Bee time, OR        vibration.
                                                                    0.75-0.80 compacting factor.


Concreting of lightly reinforced sections            Low            10-15 seconds Vee-Bee time, OR
with vibration.                                                     0.80-0.85 compacting factor.


Concreting of lightly reinforced sections            Medium         5-2 seconds, Vee-Bee time, OR
without vibration, or heavily                                       0.85-0.92, compacting factor, OR
reinforced section with vibration.                                  25-75 mm, slump for 20 mm aggregate.
Concreting of heavily reinforced sections            High           Above 0.92, compacting factor, OR
without vibration.                                                  75-125 mm, slump for 20 mm aggregate

           Note :- For smaller aggregate the values of slump will be lower.
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TECHNICAL SPECIFICATION


        7.6.4 Durability - The durability of concrete depends on its resistance to
deterioration and the environment in which it is placed. The resistance of concrete to
weathering, chemical attack, abrasion, frost and fire depends largely upon its quality &
constituent materials. Succeptibility to corrosion of the steel is governed by the cover
provided and the permeability of concrete. The cube-crushing strength alone is not a reliable guide
to the quality and durability of concrete;it must also have an adequate cement content and a low water
cement ratio.


       One of the main characteristics influencing the durability of any concrete is its
permeability. W ith strong, dense aggregates, a suitably low permeability is achieved by
having a sufficiently low water -cement ratio, by ensuring as thorough compaction of the
concrete as possible and by ensuring sufficient hydration of the cement through proper
curing methods. Therefore, for given aggregates, the cement content should be sufficient
to provide adequate workability with a low water c ement ratio so that concrete can be
completely compacted with the means available.


        Appendix IV provides guidance regarding minimum cement content and permissible
limits of chloride and sulphate in concrete.


7.7 PRODUCTION AND CONTROL OF CONCRETE:


      7.7.1 General - Salt, clay, powdery coating, soluble chemical salts and light weight
materials are usually removable by washing. Aggregates should be washed before
batching with clear water free from alkali, salt and other impurities.


        7.7.2 Batching :


       7.7.2.1 Measurement of Materials - The method of measuring materials for
concrete shall be such that the proportions are controlled and readily checked at any time
during the progress of the work. Materials shall be measured as per procedure given
below.


      Weigh Batchers- All weighing devices shall be subject to approval and weigh
batchers shall meet the following requirements : -


       (a)    The accuracy shall be of the order - set for the purpose and shall be such
that the indicated weight of any hopper full of material does not vary more than one
percent from the required weight.


      (b)     The weighing equipment shall be designed to permit ready and proper
adjustment of the proportions of the mix.


      (c)     The equipment shall be capable of so controlling the rate of delivery of each
kind and size of materials that the combined inaccurac y in feeding and measuring during
normal operations does not exceed 3 percent for all aggregates and 1 percent for water.



                                                                                                  242
TECHNICAL SPECIFICATION




       (d)   The operating mechanism for measuring the amount of water shall be such
that no leakage occurs with the valves closed. The filling and discharge valves shall not
be opened before the filling valve is closed.


      (e)     Test scale weight shall be provided and periodic checks made of the
accuracy of all weighing equipment.


       7.7.2.2 To avoid confusion and error in batching, consideration should be given to
using the smallest practical number of different concrete mixes on any site or in any one
plant.
      A competent person shall supervise all stages of production                     of     concrete.
Preparation of test specimens and site test shall be properly supervised.


Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991          7/27



       7.7.2.3 In proportioning concrete, the quantity of both cement and aggregate should
be determined by mass. W here the mass of cement is determined on the basis of mass of
cement per bag, a reasonable number of bags should be weighed periodically to check the
net mass. W here the cement is weighed on the site and not in bags it should be weighed
separately from aggregates. W ater should be either measured by volume in calibrated
tanks or weighed. Any solid admixture that may be added, may be measured by mass;
liquid and paste admixtures by volume or mass. Batching plant where used should
conform to IS: 4925-1968.


       7.7.2.4 Except where it can be shown to the satisfaction of the Engineer -in-charge
that supply of properly graded aggregate of uniform quality can be mainta ined over the
period of work, the gradingof aggregate should be controlled by obtaining the coarse
aggregate in different sizes and blending them in the right proportions when required, the
different sizes being stacked in separate stock piles. The materi al should be stock -piled
for several hours preferably a day before use. The grading of coarse and fine aggregate
should be checked as frequently as possible, the frequenc y for a given job being
determined by the Engineer-in-charge to ensure that the specified grading is maintained.


       7.7.2.5 In case uniformity in the materials used for concrete making has been
established over a period of time, the proportioning may be done by volume batching,
provided periodic checks are made on mass/volume relationships of the materials. W here
weigh-batching is not practicable, the quantities of fine and coarse aggregate (but not
cement) may be determined by volume with the permission of Engineer -in-charge. If fine
aggregate is moist and volume batching is adopted, allow ance shall be made for bulking in
accordance with para 7.3.2.6 “Bulking of Sand”.


        A detailed note “How to batch concrete by volume” has been appended vide Appendix-VI.
       7.7.2.6 It is important to maintain the water cement ratio constant at its correct
value. To this end, determination of moisture contents in both fine and coarse aggregate
shall be made as frequently as possible, the frequenc y for a given job being determined by
the Engineer-in-charge according to weather conditions. The amount of the added water



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TECHNICAL SPECIFICATION


shall be adjusted to compensate for any observed variations in the moisture contents. For
the determination of moisture content in the aggregate, IS: 2386(Part lll)1977 may be
reffered to. To allow for the variation in mass of aggregate due to varia tion in their
moisture content, suitable adjustments in the masses of aggregates shall also be made.


        Aggregate shall not be batched when free water is dripping from the aggregate.
        7.7.3 Mixing :
        7.7.3.1 The mixing of concrete shall be done in a batch mixe r of such approved type
as will ensure the homogeneous distribution of all ingredients. The plant shall be so
designed and operated that all materials entering the mixer including water can be
accurately proportioned and readily controlled. The mixing shal l be continued until there is
a uniform distribution of the materials and the mass is uniform in colour and consistenc y.
If there is segregation after unloading from the mixer, the concrete should be remixed.
      The entire batch within the mixer shall be disc harged before recharging. The
volume of mixed material per batch shall not exceed the manufacturer’s rated capacity.
        7.7.3.2 Efficiency and Performance of Mixer:
      7.7.3.2.1 The efficienc y and performance of the mixer shall be periodically checked.
The mixing efficienc y, that is an index of the uniformity of the mixed concrete, can be
evaluated by finding the percentage variation in


      quantity of cement, fine aggregate and coarse aggregate in freshly mixed batch of
concrete. The percentage variation between the quantites of cement,
Volume I –Sec..IV               Specifications For Irrigation Projects Nov. 1991   7/28



fine aggregate (as found by weighing in water) in the two halves of the batch and the
average of the two halves of the batch shall not exceed the following limits : -


                          Cement.                ...            8 percent.

                          Fine aggregate.        ...            6 percent.

                          Coarse aggregate.      ...            5 percent.


      The mixer shall comply with IS: 1791 -1985 and its performance should be tested
according to IS: 4634-1968.


       7.7.3.2.2 A mixer will be considered unsatisfactory if from three tests of any one
batch a range in slump exceeding 25 mm or a range in air content exceeding one percent
is given between representative sample taken at differe nt portions of the mixer discharge.


      7.7.3.2.3 For any one mix, the variation in the air free unit weights of three
samples taken from the front, centre and back of a batch of concrete in the mixer, shall
not exceed the following :-




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TECHNICAL SPECIFICATION


                     For one batch                 ...        37.2 Kg per cu.m

                     Average of 3 batches          ...        23.9 Kg per cu.m

                     Average of 20 batches         ...        19.4 Kg per cu.m

                     Average of 90 batches         ...        14.6 Kg per cu.m


       7.7.3.3 Method of Charging - The proper sequence of operations for the admission
of aggregates into any type of mixer shall be ascertained by trial runs conducted in order
to determine the method giving the best results. The following sequence of charging the
mixer may be adopted : -


       (a)    Five to Ten percent of the total quantity of water required for mixing,
adequate to wet the drum thoroughly, shall be introduced before the other ingredients in
order to prevent any caking of cement on the blades or sides of the mixers.


       (b)    All dr y ingredients (cement and both fine and coarse aggregate) shall be
simultaneously ribboned into the mixer in such a manner that the period of flow for each
ingredient is about the same. Eighty to ninety percent of the total quantity of water
required for mixing shall be added uniformly along with the dry ingredients.


       (c)    The remaining quantity of water shall be added after all the other ingredients
are in the mixer.


       (d)      Cobbles or a portion of the coarsest aggregate, however, may be added last;
this facilitates the clearance of the chutes and removes any fine aggregate or cement
adhering to the sides.


       7.7.3.4 Time of     Mixing - Unless otherwise permitted, machine mixing of each batch
shall continue for not     less than the period indicated in Table 16. During this period the
drum shall be rotated      at a speed recommended by the manufacturer. The mixing period
shall be timed after all   materials, including water, are in the drum.




Volume I –Sec..IV             Specifications For Irrigation Projects Nov. 1991                  7/29


                                                 TABLE - 16
                                               Time of Mixing

       Capacity of Mixer                                       Time of Mixing

                                                   Natural                       Manufactured



                                                                                                       245
TECHNICAL SPECIFICATION


                                                   aggregate                     aggregate
       One cubic metre or less.                    1-1/4 minutes                 1-1/2 minutes
       Two cubic metres.                           1-1/2 minutes                 2 minutes
       Three cubic metres or larger.               2 minutes 2-1/2 minutes.

       7.7.3.5 Each mixer shall have a mechanically operated timing device for signalling
the completion of the required mixing period. The actual time of mixing shall be checked at
least twice during each shift and the timing device shall be adjusted if in error.

       The timing device shall be so interlocked with the discharge gate of the batch
hopper that timing does not start until the discharge gate is ful ly closed and all ingredients
are in drum. A suitable record shall be kept of the average time consumed in charging,
mixing and discharging a batch during each run.

        Excessive mixing, necessitating the addition of water to provide workability shall be avoided.

       7.7.3.6 Discharging - The full contents of the drum shall be discharged quickly so
as to avoid segregation.

      W hen the mixer is stopped and has been out of use for more than 30 minutes
before placing again any ingredients in the mixer, all hardened concrete or mortar shall be
removed from the inner surface of the mixer.

       The first concrete batch at the start of the day’s work shall be made richer by 10%,
the first batch of concrete from the mixer shall contain only two thirds of the normal
quantity of coarse aggregates.

       7.7.3.7 Retempering - The retempering of partially hardened concrete or mortar
requiring renewed mixing, with or without the addition of cement, aggregate or water, shall
not be permitted.

        7.7.4 Hand Mixing - Hand mixing shall be avoided in mass concrete construction. When hand
mixing is permitted by the Engineer-in-charge for small jobs or for certain other reasons, it shall be done
on a smooth watertight platform large enough to allow efficient turning over of the ingredients of concrete
before and after adding water. Mixing platform shall be so arranged that no foreign material shall get
mixed with concrete nor does the mixing water flow out. Cement in required number of bags shall be
placed in a uniform layer on top of the measured quantity of fine aggregate, which shall also be spread in
a layer of uniform thickness on the mixing platform. Dry sand and cement shall then be mixed thoroughly
by turning over to get a mixture of uniform colour. Enough water shall then be added gradually through a
rose and the mass turned over till a mortar of required consistency is obtained. Measured quantity of
coarse aggregate shall then be placed on the mixing platform and wetted till the mortar and mixture
obtained is of uniform colour and required consistency. In hand mixing quantity of cement shall be
increased by 10 percent more than the quantity provided in the mix design or nominal mix proportioning.
7.8 FORM WORK:
        7.8.1 Forms shall be used wherever necessary to continu e the concrete and shape
it to the required lines or to ensure against contamination of the concrete by material
caving or sloughing from adjacent surface left by excavations or other features of the
work. All exposed concrete surfaces having slopes of 2 h orizontal to 1 vertical or greater
shall be formed.
Volume I –Sec..IV             Specifications For Irrigation Projects Nov. 1991               7/30


       7.8.1.2 Form work may be of timber, steel or precast concrete panels, or of such other suitable
materials or combination of such materials. Form work shall be substantially and rigidly constructed to the
shapes, lines and dimensions required, efficiently propped and braced to prevent deformation due to



                                                                                                         246
TECHNICAL SPECIFICATION


placing, vibrating and compacting concrete, other incidental loads or to the effect of weather. If settlement
or deflection of forms under the load of fresh concrete is to be expected, allowance should be made in the
original construction of the forms so that, the finished lines and dimensions of the structure are in accordance with
those specified on the drawing.

        7.8.1.3 The surfaces of form work shall be made to produce surface finishes as specified and
form work joints space be tight enough to prevent loss of liquid from concrete. Joints between the form
work and existing concrete structures shall also be ‘grout tight’. Form work shall be arranged to facilitate
easing and removing of the various parts in correct sequence, without jarring or damaging the concrete.
Fixing blocks, bolts or similar devices may be embedded in the concrete, provided they do not reduce the
strength or effective cover of any part of the structure below the required standard but the use of through
bolts shall be avoided wherever possible. Temporary opening shall be provided at all points necessary in
the forms to facilitate clearing and inspection immediately before the placing of the concrete.

        7.8.1.4 Forms shall overlap the hardened concrete in the lift previously placed by not more than
75 mm, and shall be tightened smugly against the hardened concrete so that when concrete placement is
resumed, the forms will not spread and allow offsets or loss of mortar at construction joints. Additional
bolts or forms ties shall be used as necessary to hold forms tight against hardened concrete. Particular
attention shall be paid in setting the forms and tightening for construction joints so as get a smooth joint,
free from sharp deviations or projections.

     7.8.1.5 Moulding strips shall be placed in the corners of forms so as to produce
chamfered edges as required on permanently exposed concrete surface.

7.8.2 Materials to be used :

       7.8.2.1 Materials used for form sheathing and lining shall conform with the following
requirements :-

Required             Timber Sheathing or Lining                                Steel Sheathing or Lining
Finish
  1.                                  2.                                                   3.

 F1       Any type and grade meeting the dimensional                  Steel sheathing permitted, Steel
          requirements of surface finish except that                  lining permitted except on surfaces
          metal forms shall be used on surfaces of                    of internal transverse and logitudinal
          internal transverse and longitudinal joints                 joints in the dam where steel
          in the dam.                                                 sheathing is required.

 F2       Common grade timber or plywood sheathing Steel sheathing permitted. Steel
          or lining.                               lining permitted, if strongly supported.

 F3       For plane surfaces, common grade timber or Steel sheathing permitted, Steel
          better T & S or plywood.                   lining permitted, if strongly supported.

 F-4      For warped surfaces, timber which is free   Steel sheathing permitted. Steel
          from knots and other imperfections and      lining not permitted.
          which can be cut and bent accurately to the
          required curvatures without splintering or
          splitting.

        * Steel sheathing denotes steel sheaths not supported by a backing of timber
boards.Steel lining denotes steel sheaths supported by a backing of timber boards.
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                                                                                                                247
TECHNICAL SPECIFICATION




        7.8.2.2 Timber sheathing or lining shall be of such kind and quality or shall be so
treated or coated that there will be no chemical deterioration or discolouration of the
formed concrete surfaces. The type and condition of form sheathing and lining and the
ability of forms to withstand distortion caused by placement, and vibration of the concrete,
and the workmanship used in the form construction shall be such that the formed surfaces
will conform with applicable requirements of this specification pertaining to f inish of
formed surfaces.
        Forms for concrete surfaces required to receive F2 and F3 finishes described under
para 7.15.1.3.2, 7.15.1.3.3 shall be constructed so as to produce uniform and consistent
texture and pattern on the concrete faces. Metal patches o n forms for these faces will not
be permitted. The form sheathing or lining shall be so placed that all horizontal form
marks are contiuous across the entire surface. W here finish F2 is specified, the sheathing
or lining shall be placed so that, the joint marks on the concrete surfaces will be in general
alignment both horizontally and vertically and the form sheathing material used for such
surfaces shall be restricted to one type in any one major feature of the work.
       Forms for surfaces required to receive F4 finish as described under para 7.15.1.3.4
shall be constructed so as to conform accurately to the required curvature of the sections.
W here necessar y to meet requirements for curvature the form sheathing shall be built up
of laminated splices cut to make right, smooth form surface. The forms shall be so
constructed that the joint marks on the concrete surface shall, in general, follow the line of
water flow. After the forms have been constructed, all surface imperfections shall be
corrected, all the nails shall be hidden, and any roughness and all angles on the surface
of the forms caused by matching the forms material shall be dressed to curvature.
       If temperate hard wood is used as a form lining, it shall be continuously supported
with timber or plywood.
       7.8.2.3 Embedded ties for holding forms shall remain embedded and except where
F1 finish is permitted, shall terminate not less than two diametres or twice the minimum
dimension of the tie or ten millimetres, whichever is greater, in the formed faces of the
concrete. W here F1 finish is permitted, ties may be cut off flush with formed surface.
       The ties shall be constructed so that, removal of the ends or end fasteners can be
accomplished without causing appreciable spalling at the faces of the concrete. Re cesses
resulting from removal of the ends of the form ties shall be filled in accordance with the
provisions of para 7.16 on ‘Repairs of Concrete’.


        7.8.3 Cleaning and Treatment of Forms :


       At the time concrete is placed in the forms, the surface of the forms shall be free
from encrustations of mortar, grout or other foreign material. Before concrete is placed,
the surfaces of the forms designated to produce F2, F3 and F4 finishes shall be oiled with
a commercial form oil that will effectively prevent sti cking and will not stain the concrete
surfaces. For timber forms, form oil should consist of pure refined pale paraffin mineral oil
or other approved form oil. For steel forms, form oil shall consist of refined mineral oil
suitably compounded with one or m ore ingredient which are appropriate for the purpose.


        Care shall be taken to keep form oil out of contact with reinforcement.


        7.8.4 Removal of forms :



                                                                                          248
TECHNICAL SPECIFICATION




       7.8.4.1 Except as otherwise provided in this sub -clause forms shall be removed as
soon as the concrete has hardened sufficiently to prevent damage by careful form
removal, thus facilitating satisfactory progress with specified curing and earliest
practicable repair of surface imperfections.


       7.8.4.2 Forms on upper sloping faces of concrete, such as forms o n the water sides
of warped transitions, shall be removed as soon as the concrete has attained sufficient
stiffness
Volume I –Sec..IV              Specifications For Irrigation Projects Nov. 1991                 7/32



to prevent sagging. Any needed repairs or treatment required on such sloping surfaces
shall be performed at once and be followed immediately by the specified curing.
       7.8.4.3 In order to avoid excessive stresses in the concrete that might result from
swelling of the forms, timber forms for wall opening shall be loosened as soon as his can
be accomplished without damage to the concrete.
       7.8.4.4 Subject to approval, forms on concrete surface close to excavated rock
surface may be left in place provided that t he distance between the concrete surface and
the rock is less than 400 mm and that forms are not exposed to view after completion of
the works.
      7.8.4.5 Forms shall be removed with care so as to avoid injury to the concrete. An y
concrete damage in form removal shall be repaired in accordance with the provisions of
para 7.16, ‘Repair of Concrete’.
       7.8.4.6 The following minimum intervals of time as per IS: 456 -1978 will generally
be allowed when using ordinar y portland cement between placing concrete and str iking
form work but the period shall be modified in case of wet weather and also at the option of
the Engineer-in-charge.


          (a)        W alls columns and vertical faces of
                     all structural members.                           ...    24 to 40 hours.


          (b)        Slabs (props left under).                         ...    3 days.

          (c)        Beam (soffits).                                   ...    7 days.

          (d)        Removal of prop under :-


                     (i)    Slabs spaning upto 4.5 m.                  ...    7 days.

                     (ii)   Slabs spaning over 4.5 m.                  ...    14 days.


          (e)        Removal of props under beams and arches : -


                     (i)    Spaning upto 6 m.                          ...    14 days.




                                                                                                       249
TECHNICAL SPECIFICATION



                     (ii)    Spaning over 6 m.                          ...    21 days.

                     (iii)   Spaning over 10 m.                         ...    28 days.


       In some cases such as while using cement other than ordinary portland cement or
when conditions are not normal, it may be necessary to estimate the strength of concrete
at the time of removal of form work. Cubes if they are cast to determine the strength of
concrete at the time or removal of form work, should be cured along with the structure and
not under standard conditions envisaged for sampling and strength test of concrete. For
rapid hardening cements, 3/7 of the periods given for ordinary portland cement will be
normally sufficient, except that a minimum period of 24 hours is required.


     Due regard is to be given to curing methods to be employed before the form work is
removed.


      W hen controlled concrete of M 20 and more strength is used, the forms of slabs
may be removed when concrete has generated strength equal to double the stresses
generated by the dead load plus live load of 200 kg/m 2 .


      In any case this period shall not be less than 96 hours on placing last batch of
concrete in the slabs.




        7.8.4.7 Sequence of Removal of Forms - In respect of complicated structure
reffered to in para 7.11.2, the sequence of removal of forms may be obtained from design
office.




Volume I –Sec..IV               Specifications For Irrigation Projects Nov. 1991          7/33



7.9 HANDLING AND CONVEYING :

       7.9.1 General - The method of transporting and placing concrete shall be approved
by the Engineer-in-charge. Concrete shall be so transported and placed that no
contamination, segregation or loss of constituent materials takes place. Concrete shall be
transported as rapidly as practicable without any slump loss exceeding 25 mm or a loss in
air content more than 1% before the concrete is placed in the works.

      W here the time of haul exceeds 20 minutes, mixed concrete shall be transported
under cover protected from evaporation.

       7.9.2 Buckets - Buckets used for conveying concrete shall be capable of prompt
discharge of low slump, lean mix concrete of controlled quantities without splashing or
segregation and shall be of such capacity that there is no spliting of batches in loading
buckets. Buckets shall be of the bottom dump type, permitting an even controlled flow into
the forms or hopper without undue splashing or segregation. Cars, trucks and ships shall
be designed to facilitate uniform delivery rather than quick dumping .


                                                                                                 250
TECHNICAL SPECIFICATION




        7.9.3 Chutes - Chutes used for conveying concrete shall be of such type and shape
as to ensure a steady uniform flow of concrete in a compact mass without separation or
loss of ingredients and shall be protected from wind and such where necessary to pro tect
loss of slump by evaporation and shall be furnished with a discharge hopper. The free fall
or drop of concrete shall be limited to 150 cm. The chute sections shall be made of or
lined with metal and all runs shall have approximately same slopes not fl atter than 1
vertical to 2-1/2 horizontal. The required consistenc y of concrete shall not be changed in
order to facilitate chuting. If it becomes necessary to change the consistenc y, the concrete
mix will be completely redesigned. W herever there is a free fall within the conveying
system, suitable baffle plates, splash boards or down spouts shall be provided to prevent
segregation, splashing or loss of ingredients. W henever it is necessary to hold the
discharge of a chute more than three metre above the le vel of the fresh concrete, a
flexible down spout will be used to break the fall and confine the flow. The lower end of
the spout shall be held close to the place of deposit. W herever depositing is intermittent, a
discharge hopper will be provided. All chutes shall be thoroughly cleaned before and after each run. All
wash water and debris shall be washed outside the forms.

        7.9.4 Pumping - W here concrete is permitted to be conveyed into place by the
application of pressure, the pump and piping shall be suit ably designed and shall be of
adequate capacity for the work. Pumping shall be permitted only for conveying concrete
containing aggregates less than 7.5 cm maximum size. The operation of the pumping
system shall be such that a continous stream of concrete, without air pockets or
interruptions, is delivered. At the end of the run, all concrete remaining in the pipe line
shall be rejected in such a manner as to avoid any segregation or lack of uniformity. The
pump and line shall be thoroughly cleaned and all wash water and debris wasted.
        7.9.5 Belt Conveyors - W here transportation by means of belt conveyors is
permitted, a steady, uniform flow of concrete shall be maintained without any segregation
or pilling up on steep inclines or at transfer points. The con veyor shall be covered to
prevent damage by rain, loss of heat during cold weather, evaporation or heating by the
direct rays of sun, or other deterioration of the concrete. Concrete shall not be discharged
directly into the forms, unless the discharge end of the conveyor or pipe can be readily
moved about within the forms so as to place the concrete in even layers as specified
under7.10.3 and 7.10.11. Otherwise, suitable hoppers shall be provided, from which the
concrete shall be dumped in place by means o f buckets and short chutes or spouts.
        7.9.6 Cleaning and Washing of Equipments - Equipment used for transporting
concrete from the mixer to the form shall be maintained free from deposit of stiff concrete
and leakage of mortar. Batch containers, transit mixers, chutes, concrete pumps, pipe
lines and
Volume I –Sec..IV            Specifications For Irrigation Projects Nov. 1991          7/34


discharge hoppers shall be thoroughly cleaned after each run and wash water and debris
wasted outside the forms.

7.10 PREPARATIONS FOR PLACING CONCRETE :

      7.10.1 Before depositing any concrete for the next lift or pour, the forms shall not
be retightened. The surface of contact shall be allowed to dry out between placing
successive lifts of concrete. The top of the previously deposited concrete shall be
thoroughly cleaned and prepared as specified under para 7.10.4.

        7.10.2 Rock Foundations :

       7.10.2.1 All rock surfaces against which concrete is to be placed shall be clean and
free from mud, dirt, oil, organic deposits, or other foreign material which ma y prevent a



                                                                                                   251
TECHNICAL SPECIFICATION


tight bond between the rock and concrete. Seams shall be cleaned to a suitable depth and
to firm rock along the sides. W here excavation methods or the natural rock strata do not
leave a sufficiently rough surface of contact, the bed shall be ro ughened by cutting steps,
grooves, trenches, or keyways into the solid rock. Scaly coatings, hardened grout or
concrete, construction debris, and other objectionable materials shall be removed.
Seepage shall be properly controlled and diverted. The foundat ion bed and sides shall be
carefully cleaned with stiff brooms, picks, jets of water and air applied at high velocity or
other equally effective means, followed by thoroughly washing. After washing and before
placing any concrete, water shall be removed fr om depressions and the rock surface shall
be left uniformly damp. If any drilled hole is left in the foundation surface which is no
longer needed, the holes shall be cleaned with air water jetting and filled up completely
with cement slurr y.

      7.10.2.2 All flat surface shall then be coated with mortar about 1.5 cm thick in the
case of concrete surfaces and 2 cm thick on rock surfaces. The water cement ratio for the
mortar layer shall not exceed that for the regular concrete mixture, and the mortar shall be
of such consistenc y that it can be spread evenly without flowing. It shall be thoroughly
broomed and worked into all irregularities, cracks and crevices. The manner of spreading
and working shall be such as not to cause any segregation, and concrete shall be placed
immediately upon the fresh mortar before its initial set.

      7.10.2.3 No concrete shall be deposited until the foundation has been inspected
and approved. W here the rock is dr y enough to absorb water from the mortar layer, it shall
be soaked for at least 24 hours prior to placing the concrete. Detailed instructions shall be
issued for preparing scaly or cracked foundations requiring special treatment or grouting.

        7.10.2.4 On ver y rough or broken surface the first few batches of concrete may, if
so required, contain only about one half the regular proportion of coarse aggregate.
        7.10.3 Earth or Shale Foundation :
        7.10.3.1 In the case of shale foundation, all soft or loose mud and surface debris
shall be scraped and removed. The surface shall be moist ened to a depth of about 15 cm
to prevent the subgrade from absorbing water from the fresh concrete. Just before placing
the concrete the surface of the earth shall be tamped or otherwise consolidated
sufficiently to prevent contamination of concrete durin g placing. In general, concrete shall
be deposited only upon material lying in natural undisturbed state.
        7.10.3.2 Foundations of porous or free draining materials shall be thoroughly compacted by
flushing and by subsequent tamping or rolling, if necessary. The finished foundation surface shall then be
blanketed with a layer of tar paper or closely woven burlap, carefully lapped and fastened down along the
seams so as to prevent the loss of mortar from the concrete.
        7.10.3.3 Unless otherwise specified, the under-drainage system for all foundations shall be
blanketed as specified under para 7.10.3.2
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7.11 PLACING OF CONCRETE :


       7.11.1 General - No concrete shall be placed until the place of deposit has been
thoroughly inspected and approved by Engineer-in-charge, all reinforcement, inserts and
embedded metal properly secured in position and checked, and forms thoroughly wetted
(except in freezing weather or oiled). Placing shall be continued without avoidable
interruption while the section is completed or satisfactory constructed joint made. The
position and arrangement of construction joint shall be indicated by the designer.




                                                                                                     252
TECHNICAL SPECIFICATION


       If concreting is not started within 24 hours of the approval being given, it shall have
to be obtained again from the Engineer-in-charge.


        During cold weather, concreting shall not be done when the temperature falls below
4.5 o C. The concrete placed shall be protected against frost by suitable coverings.
concrete damaged by frost shall be removed and work redone. During hot weather,
precautions shall be taken to see that temperature of wet concrete does not exceed 40 o C.
      7.11.2 Sequence of Concrete - In respect of complicated structures such as
continuous bridges, balanced cantilever bridges, cantilever canopies mo re than 3 m, rigid
framed structures, box type structures etc., the sequence of concreting must be stipulated
in drawing. If this is not given in drawing it should be obtained from design office and
concreting done accordingly.
       7.11.3 Within Forms - Concrete shall be s ystematically deposited in shallow layers
and at such rate as to maintain, until the completion of the unit, a plastic surface
approximately horizontal throughout. Each layer shall be thoroughly compacted before
placing the succeeding layer. In general, the thickness of layers shall not exceed the
following limits.


          (a)    Vibrated mass concrete.           ...     45 cm.

          (b)    Hard compacted mass concrete.     ...     30 cm.

          (c)    Reinforced concrete.              ...     25 cm.


       The batches shall be deposited vertically in suc h a manner so as to avoid
segregation, air pockets, or damage to other recently placed concrete. In so far as it is
practicable, concrete shall be placed directly in its final position and shall not be caused
to flow in a manner to permit or cause segregat ion. Method and equipment employed in
placing concrete will ensure that aggregate is not separated from the concrete mass.
        In placing mass concrete in a lift, successive batching of concrete shall be placed
in a s ystematic arrangement in order to avoid long exposure of parts of the live surface of
a concrete layer. W herever necessary, both the forms and reinforcement shall be
protected against splashing, and all accumulations or partially set, dried, or caked mortar
which may impair the bond or show in t he finished faces, shall be removed and wasted
before commencing concreting operations.
7.11.4 Cleaning Joints :
      7.11.4.1 W hen the work has to be             resumed on a surface which has
hardened, such surface shall be roughened. It shall then be swept clean so as to expose
sound concrete surface. The method shall be by means of jets of air and water applied at
high velocity with such additional roughening of the surface by means of stiff wire brushes
as may be required. Brushing shall be done by jabbing and digging into the surface rather
than by merely sweeping. The whole process shall be conducted in such manner as not to
loosen the coarse aggregates but vigorously enough to expose a fresh clean -cut concrete
surface.
      Immediately before depositing fresh concrete, the contact surface shall again be
gone over and thoroughly washed to remove all debris and loose material. Th e final pick -
up of




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TECHNICAL SPECIFICATION


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loose materials shall be made near the centre of the joint and away from the outside
edges of the masonr y. Dry contact surface shall be kept saturated with water for not less
than 24 hours, but all satnding water shall be removed from depressions before spreading
the layer of mortar or cement slurry.
      For horizontal joints the surface shall be covered w ith a layer of mortar about 10 to
15 mm thick. The mortar will have the same proportions of water, air entraining agent,
cement and fine aggregate as the concrete mixture which is to be placed upon it. The
water cement ratio of the mortar in places shall n ot exceed that of the concrete to be
placed upon it, and the consistency of the mortar shall be suitable for being spread
uniformly and worked thoroughly into all irregularities of the surface.
       For vertical and inclined joints (surfaces) which cannot be co vered with mortar shall
be given a heavy coat of neat cement grout, vigorously brushed into all interstices and
hollows or neat cement slurr y shall be applied on the surface before it is dry so as to
provide the best possible conditions for bond and imperm eability. This layer of cement
slurry or mortar shall be freshly mixed and applied immediately before placing of the
concrete.


       7.11.4.2 W here the concrete has not fully hardened, all laitance shall be removed
by scrubbing the wet surface with wire or bristle brushes, care being taken to avoid
dislodgement of particles of aggregate. The surface shall be thoroughly wetted and all free
water removed. The surface shall then be coated with neat cement slurry. On this surface,
a layer of concrete not exceeding 150 mm in thickness shall first be placed and shall be
well rammed against old work, particular attention being paid to corners and close spots;
work thereafter shall proceed in the normal way.


       7.11.4.3 Should the next lift be delayed the contact surface shall be kept wet and
covered so as to minimise the evaporation of curing water which may cause an injurious
coating on the joint. W here necessary all defective and undesirable concrete shall be
removed by chipping and picking by hand or, if so required, by wet sand blasting the top,
to a depth just sufficient to expose a fresh, clean -cut surface over the entire area, which
shall then be thoroughly flushed with water. Every precaution shall be taken to afford
suitable bond for the succeeding lift.
      7.11.4.4    If from any cause, the working surface is left exposed until it has
hardened to a considerable extent, it shall be left to set and cure for not less than 56
hours or longer of necessary until a strength greater than 35.21 g/cm 2 (500 PSI) has been
attained, before completing the lift. The surface thus, interrupted shall be treated in same
manner as described in para 7.11.4.1.
      Hardened surfaces of old masonry on which new concrete is to be placed, shall
unless otherwise ordered, be prepared in the same manner as provided for rock
foundations under para 7.10.2.
       7.11.5 Rate of Placing - Concreting shall be continued without avoidable
interruption until the structure or section is completed or until satisfactory constr uction
joints can be made. Concrete shall not be placed faster than the placing crew can compact
it properly. In placing concrete in thin members and columns, precautions shall be taken
against too rapid a placement which may result in movement or failure of the form due to
excessive internal pressure. An interval of atleast 4 and preferably 24 hours should
elapse between the completion of columns and walls and the placing of the slabs, beams
or girders supported by them in order to avoid cracking due to s ettlement. All concrete



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TECHNICAL SPECIFICATION


shall be placed in approximately horizontal lifts not exceeding 150 cm in thickness except
to expedite the placing of embedded material. The interval between two lifts shall also be
maintained as constant as possible, and the differ ence of elevation between any two
adjacent blocks shall not be more than 900 cm and not less than 150 cm. A period of 5
days for 150 cm of concrete laid shall be allowed before the next pour unless heat
dissipation methods warrant otherwise.




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        7.11.6 Placing “Plums in Concrete” :


       7.11.6.1 In mass concrete members, stone plums may be used, with a view to effect
econom y, in zones not subject to tensile stresses upto a maximum limit of 20 percent by
volume of concrete when specifically permitted by the Engineer -in-charge. W hile placing
plums, care shall be taken that clear distance between any two plums is not less than
either the width or thickness of either of the plums or 15 cms whichever is more. No stone
shall be closer than 30 cm to an exposed surface. The stones shall not be dropped in
place, but each stone shall be laid and carefully embedded so as to avoid any injury to the
forms or adjacent masonr y and in such a manner that no planes of weakness or necessary
seams occur in the structure.


       7.11.6.2 During concreting, the first layer o f concrete of the specified mix shall be
laid to a thickness of atleast two and a half times the thickness of the maximum size of
plums to be used. The plums shall then be laid while the top portion of this concrete is still
green but sufficiently stiff to prevent complete submergence of the plums under their own
weight. These plums shall be about half embedded in the concrete and the remaining part
exposed so as to form a key with the next layer of concrete. No plums shall be used for
concrete laid under water.


      7.11.6.3 If plums of stratified stone are used, they shall be laid on their natural
bed. Stones with concave faces shall be laid with the concave face upwards.


       7.11.6.4 The thickness of the next and successive layers of concrete shall be at
least twice that of the largest plum.


       7.11.7 In placing mass concrete, the exposed area of fresh concrete shall be
maintained at the practical minimum by first building up the concrete in successive
approximately horizontal layers to the full width of the blo ck and to full height of the lift
over a restricted area at the down stream end of the block and then continuing upstream
in a similar progressive stages to the full area. The slopes formed by the unconfined
upstream edges of the successive layers of concr ete shall be kept as steep as practicable
in order to keep its area minimum. Concrete along these edges shall not be vibrated until
adjacent concrete in the layer is placed, except that it is shall be vibrated immediately
when weather conditions are such t hat the concrete will harden to an extent later vibration
may not fully consolidate and integrate it with more recently placed adjacent concrete.
      7.11.8 In formed work, structural concrete placements shall generally be started
with an over-sanded mix containing 20 mm maximum size aggregate and an extra bag of


                                                                                          255
TECHNICAL SPECIFICATION


cement per cubic metre and having a 125 mm slump placed several centimetres deep on
the joints at the bottom of the form. Concrete placement shall commence immediately
thereafter.
       7.11.9    If concrete is placed monolithically around opening having vertical
dimensions greater than 0.6 metre, or if concrete in decks floor slabs, beams, girders, or
other similar parts of a structure is placed monolithically with supporting concrete, the
following instructions shall be strictly observed.
       (i) Placing of concrete shall be delayed not less than one hour nor more than three
hours at the top of openings and at the bottom of fillets under decks, floor slabs, beams,
girders or other similar parts of structures when fillets are specified and at the bottom of
such structures, members when fillets are not specified but in no case shall the placing be
delayed so long that, the vibrating until will not of its weight readily penetrate the concrete
placed before the delay. W hen consolidating concrete placed after the delay, the vibrating
unit shall penetrate or vibrate the concrete placed before the delay.


      (ii) The last 0.6 metre or more of concrete placed immediately before the delay shall
be placed with as low slump as p raticable and shall be thoroughly compacted.
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      (iii) The surfaces of concrete where delays are made shall be clean and f ree from
loose and foreign materials when concrete placing is started after the delay.


       (iv) Concrete placed over openings and in decks, floors, beams, girders and other
similar parts of structures shall be placed with as low slump as practicable.


       (v) Concrete should be deposited at or near to final position in the placement,
eliminating the tendency to segregate when it has to flow laterally into place, at sloping
surfaces, concrete should be placed at the lower end of the slopes first, progressing
upward and thereby increasing natural compaction of the concrete. High velocity
discharge of concrete, which may cause segregation of the concrete should be avoided.
       7.11.10 Large Blocks - In placing concrete in large blocks, the work shall in
general proceed from the low side so that the working face is never excessively steep nor
long. However, for construction joints in dams, the work shall proceed from the high side
to the low side so as to maintain in upward slope in the downstream direction unless
construction joints are otherwise shown on the drawings. Under no condition shall the
slope be so steep as to cause the concrete to flow without working or to cause any
segregation. The concrete shall be deposited as nearly as practicable in final position and
shall not be piled up in large masses at any point and then pushed, shovelled, or vibrated
into space for long distances. It shall be brought up evenly around all large openings,
conduits, or embedded metal so as to minimize unequal pressure and avoid displace ment.
For large blocks of concrete in dams and other massive structures, the sequence and rate
of casting successive lifts and adjacent blocks shall be such as to facilitate the dissipation
of the heat of hydration.
      7.11.11 Fissures - W here fissures in concrete are necessary to be produced (e.g.
in bucket invert etc.) the use of fissure reinforcement concrete may be considered by the
Engineer-in-charge.
       All concrete construction shall conform to the permissible tolerance and technical
provisions as described in this section and to the detailed requirements of the following
paragraphs. All structures shall be built in a workman like manner and to the lines, grades


                                                                                           256
TECHNICAL SPECIFICATION


and dimensions shown in the drawings or prescribed by the Engineer -in-charge. The
location of all construction joints shall be subject to the approval of the Engineer -in-
charge. The dimension of each structure shown on the drawings will be subject to such
changes as may be found necessary by the Engineer -in-charge to adopt structures to the
conditions disclosed by the excavation or otherwise.


       7.11.12    Concrete in the Dam (upto Crest Level including Concrete in
Bucket/Stilling Basin)- This item of the schedule for concrete in dam includes all
concrete in the main structure of the dam between the normal upstream and downstream
faces of the dam upto crest level, including concrete in block outs but excludes concrete
in spillway bridge piers (above crest level), elevator shaft (above crest level), training
walls (above crest level), concrete in side walls, kerbs and parapets and concrete in
shafts in foundation faults and seams. Concrete in upstream and downstream faces of the
dam to a thickness to be prescribed by the Engineer -in-charge may differ in mix
proportions from the concrete in the interior of the dam and may contain more cement per
unit volume of concrete. The concrete in the dam also includes the foundation of the
trash rack structure, river sluices and irrigation sluices. All concrete in the dam shall be
placed in horizontal lifts not exceeding 150 cm in thickness and shall be placed and built
up to the full height of the lift in accordance with the provisions of relevant part of this
section.
       The forms of surfaces between adjacent blocks may be removed as soon as th e
concrete has hardened sufficiently to prevent the surface damage. Except as provided
below, the placing of concrete in the dam shall be so regulated that the maximum
differential height between adjacent blocks shall not exceed 9 m; unless relaxed by the
Engineer-in-charge.
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        The rate of placing concrete in any block of the dam shall be such that not more
than one lift shall be placed in 72 hours. Every efforts shall be made to obtain a regular
periodic placement of successive lifts throughout the dam. All concrete in the dam shall be
cooled as provided in the relevant part of this section. All outlets/galleries and other
sizeable opening within mass concrete shall be closed or bulk headed at the faces of the
dam and other exposed surfaces from the time, concrete is placed around the openings
until the concrete surrounding the openings is completely cooled.


       Plumb line walls shall be formed in the concrete where shown on the drawings or
directed and plumb shall be maintained within 12 mm.


       7.11.13 Concrete in Dam (above Crest Level) - The item of schedule for concrete
in dam includes all concrete above crest level in piers, a butments, elevator shaft, taining
walls, non-overflow portion of dam, power dam and block outs.


       7.11.14 Concrete in Spillway Bridge, Side Walls, Kerbs and Parapets - The item
of the schedule for concrete in spillway bridge, kerbs and parapets include all concrete in
the spillway bridge, kerbs and parapets in full length of the masonry dam block outs.


      Pre-moulded bitumeneous fibre type expansion joint material, shall be placed in the
expansion joints.




                                                                                        257
TECHNICAL SPECIFICATION




       Lighting recesses shall be constructed in the parapets as directed by the Engineer-
in-charge. Open joints or false joints shall be constructed as shown on the drawings or as
directed by the Engineer-in-charge. Preformed expansion joint filler shall be placed in the
road way and side walks where shown on the d rawings or as directed by the Engineer -in-
charge.


       7.11.15 Concrete in Blockouts - All concrete required to be placed in blockouts to
permit the installation and adjustment of mechanical and other equipments shall be
included in the respective concrete as described above. The concrete surfaces of the
blockouts shall be chipped and roughened as described hereinafter before the concrete is
placed in the blockouts.


      Exceptional care shall be taken in placing the concrete in blockouts in order to
ensure satisfactor y bond with the concrete previously placed and to secure complete
contact with all metal work in blockouts.


       The roughening of the concrete surface of the blockouts shall be performed by
chipping or sand blasting as approved by the Engineer -in-charge and in such a manner as
not to loosen, crack or shatter any part of the concrete beyond the roughened surface.
After being roughened, the surface of the concrete shall be cleaned thoroughly of loose
fragments, dirt and other objectionable substances and sha ll be sound and hard to ensure
good mechanical bond between the existing and new concrete.


       All concrete which is not hard, dense and durable shall be removed to the depth
required to assure its surface satisfactory to the Engineer -in-charge.
       7.11.16 Rejected Concrete - All concrete of inferior quality shall be rejected and
removed from the site of operations, if possible, before placing fresh concrete; where
concrete has already been placed, if found inferior, it shall be dug out and removed f rom
the forms. Any batch, too stiff for proper placement or in such a condition that it cannot be
properly compacted, shall be removed.
7.12 CONCRETING UNDER SPECIAL CONDITIONS :


      7.12.1 Work in Extreme Weather Conditions - During hot or cold weather
concreting should be done as per the procedure set out in IS: 7861, Part l or Part ll.
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       7.12.2 Under Water Concreting - W hen it is necessary to deposit concrete under
water, the methods,equipment, material and proportions of the mix to be used shall be
submitted to and approved by the Engineer -in-charge before the work is started. In no
case shall such concrete be consider ed as ‘Design mix concrete’.
       The concrete shall contain at least 10 percent more cement than that required for
the same mix placed in the dr y condition, the quantity of extra cement varying with
conditions of placing. The volume or mass of the coarse aggre gate shall be not less than
one and a half times, nor more than twice that of the fine aggregate. The materials shall
be so proportioned as to produce a concrete having a slump of not less than 100 mm, and not more
than 180 mm.



                                                                                            258
TECHNICAL SPECIFICATION


        Coffer dams or forms shall b e sufficiently tight to ensure still water if practicable,
and in any case to reduce the flow of water to less than 3 m per minute through the space
into which concrete is to be deposited. Coffer dams or forms in still water shall be
sufficiently tight to prevent loss of mortar through the walls. Dewatering by pumping shall
not be done while concrete is being placed or until 24 hours thereafter.
       Concrete shall be deposited continously until it is brought to the required height.
W hile depositing, the top s urface shall be kept as nearly level as possible and the
formation of seems avoided. The methods to be used for depositing concrete under water
shall be one of the following : -
       (a) Tremie - W hen concrete is to be deposited under water by means of a tre mie,
the top section of the tremie shall have a hopper large enough to hold one entire batch of
the mix or the entire contents of the transporting bucket if any. The tremie pipe shall be
not less than 200 mm in diameter and shall be large enough to allow a free flow of
concrete and strong enough to withstand the external pressure of the water in which it is
suspended, even if a partial vaccum develops inside the pipe. Preferably, flanged steel
pipe of adequate strength for the job should be used. A separate lifting device shall be
provided for each tremie pipe with its hopper at the upper end. Unless the lower end of the
pipe is equipped with an approved automatic check valve, the upper end of the pipe shall
be plugged with a wadding of the gunny sacking or other approved material before
delivering the concrete to the tremie pipe through the hopper, so that when the concrete is
forced down from the hopper to the pipe, it will force the plug (and along with it any water
in the pipe) down the pipe and out of th e bottom end, thus establishing a continuous
stream of concrete. It will be necessary to raise slowly the tremie in order to cause a
uniform flow of the concrete, but the tremie shall not be emptied so that water enters the
pipe. At all times after the pla cing of concrete is started and until all the concrete is
placed, the lower end of the tremie pipe shall be below the top surface of the plastic
concrete. This will cause the concrete to build up from below instead of flowing out over
the surface and thus avoid formation of laitance layers. If the charge in the tremie is lost
while depositing, the tremie shall be raised above the concrete surface, and unless sealed
by a check valve, it shall be replugged at the top end, as at the begining, before refilling
for depositing concrete.
       (b) Drop Bottom Bucket - The top of the bucket shall be covered with a canvas
flap. The bottom doors shall open freely downward and outward when tripped. The
bucket shall be filled completely and lowered slowly to avoid backwash . The bottom doors
shall not be opened until the bucket rests on the surface upon which the concrete is to be
deposited and when discharged, shall be withdrawn slowly until well above the concrete.
      (c) Bags of at least 0.028 cu.m capacity of jute or other coarse cloth shall be filled
about two thirds full of concrete, the spare end turned under so that bag is square and
securely tied. They shall be placed carefully in header and stretcher courses so that the
whole mass in interlocked. Bags used for this pur pose shall be free from deleterious
materials.


 (d) Grouting - A series of round cages made from 50 mm mesh of 6 mm steel and
extending over the full height to be concreted shall be prepared and laid vertically over the




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area to be concreted so that the distance between centres of the cages and also to the
faces of the concrete shall not exceed one metre. Stone aggregate of not less than 50 mm



                                                                                           259
TECHNICAL SPECIFICATION


not more than 200 mm size shall be deposited outside the steel cages over the full area
and height to be concreted with due care to prevent displacement of the cages.
       A stable 1:2 cement - Sand grout with a water cement ratio of not less than 0.6 and
not more than 0.8 shall be prepared in a mechanical mixer and sent down under pressure
(about 0.2 N/mm 2 ) through 38 to 50 mm diameter pipes terminating into steel cages, about
50 mm above the bottom of the concrete. As the grouting proceeds, the pipe shall be
raised gradually upto height not more than 600 mm above its starting level after which it
may be withdrawn and placed into the next cage for further grouting by the same
procedure.
       After grouting the whole area for a he ight of about 600 mm, the same operation
shall be repeated, if necessar y, for the next layer of 600 mm and so on.
      The amount of grout to be sent down shall be sufficient to fill all the voids which
may be either ascertained or assumed as 55 percent of the volume to the concreted.
      To minimise the formation of laitance, great care shall be exercised not to disturb
the concrete as far as possible while it is being deposited.


7.13 COMPACTING :
        7.13.1 Method - Concrete shall be thoroughly compacted by means of suitable tools
during and immediately after depositing. The concrete shall be worked around all
reinforcement, the reinforcement and embedded metal in proper position and to prevent
distortion.
       7.13.1.1 Compacting shall include rodding, spading,     tamping, v ibrating, treading,
and such other operations except finishing, as are necessary   to consolidate and mould the
concrete properly. The rate of placing mass concrete or         reinforced concrete in thin
sections, whether mechanically or by manual labour shall be    c learly defined.


       7.13.1.2 Accumulation of water on the surface due to bleeding, or other causes
taking place during compacting shall be stopped as much as possible by adjustments in
the mix. All free water on the surface shall be removed by sponging or mop ping. Under no
circumstances shall such accumulation of water be on the surface shall be sponging or
mopping. Under no circumstances shall such accumulation of water be covered up with
concrete or dr y concrete used to soak up excess water.
       7.13.1.3 Unless otherwise permitted, all concrete shall be compacted by mechanical
vibration. The number and type of vibrators shall be subject to the approval of the
Engineer-in-charge. In general, only vibrators of the internal type shall be used. However,
in inaccessible places in the forms, where spading, rodding, or forking is impracticable,
the concrete may be gently worked into place and compacted by light vibrating or
hammering the forms.
7.13.2 Vibrating :
      7.13.2.1 W herever practicable, concrete shall be internall y vibrated within the
forms, or in the mass, in order to increase the plasticity and to compact effectively to
improve the surface texture and appearance, and to facilitate placing of the concrete.
       7.13.2.2 The intensity and duration of vibration shall be sufficient to cause complete
settlement and compaction without any stratification of the successive layers or separation
of ingredients. Preliminar y experiments in vibrating shall be conducted under actual
conditions of mix and placement in
order to determine the optimum duration and method of vibration, as well as to develop
the necessar y skill.


                                                                                         260
TECHNICAL SPECIFICATION




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       7.13.2.3 Vibration shall be continued until the entire batch melts to a uniform
appearance and the surface just starts to glisten. A minute film of cement paste shall be
discernible between the concrete and the forms and around the reinforcement. Over
vibration causing segregation, unnecessary bleeding or formation of laitance shall be
avoided.
        7.13.3 Inernal Type Vibrators :


       7.13.3.1 Mass concrete shall be thoroughly compacted with the side of high
frequenc y, mechanical vibrators of the internal type, having not less than 3,600 and
preferably more than 5,000 impulses per minute. Immediately after depositing the
concrete, the vibrators shall be inserted into each pile, operated for 10 to 20 seconds in
one spot and then moved to another not over 90 cm (or 3 ft) away. The oper ation shall be
repeated over until the entire mass is thoroughly compacted and the pile, levelled down.
Equal attention shall be paid to the edge of the pile and to the centre. A sufficient number
of two-man vibrators shall be used to compact each batch pr operly before placing the next
one. A sufficient number of reserve vibrators in good conditions shall be kept on hand at
all times so as to assure that there is no slackening or interruption in compacting.


       7.13.3.2 The use of flexible shaft vibrators, if permitted, shall closely follow special
instructions issued for the purpose.


        7.13.3.3 Internal vibrators shall be allowed to penetrate as deeply as possible under
their own weight and shall so consolidate the successive layers as to break up effectually
all strata or seams. The vibrators shall be inserted and withdrawn slowly in such manner
as not to leave voids in the plastic concrete. The entire operation shall be conducted in a
systematic manner and each course or layer vibrated uniformly. The method of dumping or
depositing the loads shall be so arranged so as to keep the vibrators working continuously
during palcing operations. The courses shall be kept approximately level, and the concrete
even when deposited in thin layers, shall be as stiff as can b e satisfactorily worked.
However, concrete for which a slump greater than 10 cm is specified shall not be vibrated
unless otherwise ordered. Care shall be taken not to disturb a set of partially set layer.
The vibrators shall be held vertical as far as pos sible.


       7.13.3.4 Under no conditions shall internal vibrators strike the face of the forms, nor
shall reinforcement steel or embedded metal be jarred with sufficient force to impair the
bond between the concrete and the metal.


        7.13.4 External Type Vibrat ors :




                                                                                           261
TECHNICAL SPECIFICATION


       7.13.4.1 W herever so required, platform vibrators shall be used to embed all large
stone or cobble projecting above the top of the lift, but such vibrators shall be used with
caution and operated only in such manner that a depth of about 30 cm shall be thoroughly
vibrated. Particular care shall be taken in making keyways and shear grooves. W here a
raised key is required, the form shall be filled to overflowing and a platform vibrator used
to compact the concrete and bond the key to the body of the li ft.


      7.13.4.2 Form vibrators shall be permitted only for special purposes specified
under 7.13.1.3 and extreme care shall be exercised to avoid pumping air into the concrete.


        7.13.5 Surface Voids - Large voids or air pockets, which may be left in the
permanently exposed faces of the structure by vibration, shall be removed s ystematically
spading the face in the following manner. W henever practicable, a motor -driven slowly
revolving, square steel rod shall be held in a vertical position and moved slowly ba ck and
forth in short intervals along the entire face. Care shall be taken to avoid prolonging such
spading to the point of leaving excess mortar in the face.
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        7.14 CURING OF CONCRETE :
       7.14.1 General - All concrete shall be cured by water in accordance with the
requirement of para 7.14.3 of this clause or membrane curing in accordance with the
requirements of 7.14.4 of this clause. Concrete surfaces to be painted shall not be cured
by membrane curing.
       7.14.2 Curing of Unformed Surfaces and Piers - The unformed top surfaces of
walls and piers shall be moistened by covering with water saturated material or by other
effective means as soon as the concrete has hardened sufficiently to prevent damage by
water. These surfaces and steeply sloping and vertical formed surface shall be kept
completely and continuously moist, prior to and during form removal, by water applied on
the unformed top surfaces and allowed to pass down between the forms and the formed
concrete faces. This procedure shall be followed by the specified water curing and
membrane curing.


       7.14.3 Water Curing - Concrete cured with water shall be kept wet for at least 14
days. Immediately following placement of the concrete or until covered with f resh concrete
by covering with water saturated material or by a s ystem of perforated pipes, mechanical
sprinklers or porous hoses or by any other suitable method, which will keep all the surface
continuously (not periodically) wet. The period of 14 days, s pecified above shall be
increased to 21 days when pozzolana has been used in the concrete as part replacement
of cement.
        7.14.4 Membrane Curing :
       7.14.4.1 Membrane curing shall be done by application of a suitable type of white
pigmented curing compound wh ich forms a water retaining membrane on the surface of
concrete provided that on concrete surfaces which will be permanently exposed to view
clear curing compound may be required. Curing compound shall be applied to the concrete
surfaces by spraying on one coat to provide a continuous uniform membrane over all area,
with a maximum coverage per litre as prescribed by the manufacturer according to the
roughness of the surface to be covered. If necessary to cover the surface adequately a
second coat of curing compound shall be applied by spraying at right angles to the


                                                                                        262
TECHNICAL SPECIFICATION


direction at which first coat was applied. Mortar encrustation and fins on surface for which
finish F4 is specified shall be removed prior to application of curing compound. Curing
compound shall be applied to all areas of concrete surfaces except that those parts with
surface imperfections shall be omitted until repaired.
       7.14.4.2 W hen curing compound is to be used on formed concrete surfaces,
application of the compound shall commence immediate ly after the finishing operations
are completed.


      7.14.4.3 W hen curing compound is to be used on formed concrete surfaces, the
surface shall be moistened with light spray of water immediately after the forms are
removed, and shall be kept wet until the su rfaces will not absorb more moisture. As soon
as the surface film of moisture disappears but while the surface still has a damp
appearance the curing compound shall be applied. There must be ample coverage with the
compound at edges, corners and rough spot of formed surfaces. After application of curing
compound has been completed and the coating is dry to the touch, any required repair of
concrete surface shall be performed. Each repair after being finished shall be moistened
and coated with curing compound in accordance with the foregoing requirements.
        7.14.4.4 Traffic and other construction operations shall be such as to avoid damage
to coatings of curing compound for a period of not less than 28 days after application of
the curing compound. W here it is impossible because of construction operations to avoid
traffic over surfaces coated with curing compound, the membrane shall be protected by a
covering of sand or earth not less than 25 mm in thickness or by other effective means.
The protective covering shall not be placed until the sealing membrane is completely dry.
Any sealing



Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991    7/44



membrane that is damaged or that peels from concrete surfaces within 28 days after
application, shall be repaired without delay.
        7.14.4.5 Curing compound if used, shall be of approved quality.
        7.15 FINISHING OF CONCRETE SURFACE :
        7.15.1 Classes of Finish for Formed Surface :
       7.15.1.1 Allowable deviations from plumb or level and from the alignment, profile
grades and dimensions shown on the drawings are defined as “tolerance” and are to be
distinguished from the irregularities in finish as described herein. The tolerance in
concrete construction are specified in para 7.18.


       The classes of finish and requirements for finishing of concrete surface shall be as
shown on the drawings or as hereinafter specified. In the event of finishing not being
definitely specified herein or on the drawings th e finishes to be used shall be as directed.
Finishing of concrete surface shall be performed only by skilled workmen.


       Concrete surfaces will be tested where necessary to determine whether surface
irregularities are within the limits hereinafter specified.




                                                                                         263
TECHNICAL SPECIFICATION


       7.15.1.2 Surface irregularities are classified as “abrupt” or "gradual". Offset caused
by displaced or misplaced from sheathing or lining or form sections or by loose knots or
otherwise defective form timber will be considered as abrupt irregularities and will be
tested by direct measurements. All other irregularities will be considered as gradual
irregularities and will be tested by use of template, consisting of a straight edge or the
equivalent thereof for curved surfaces. The length of the template will be one and a half
metres for testing of formed surfaces and three metres for testing unformed surfaces.


       7.15.1.3 The classes of finish for formed concrete surfaces are designated by one
of the s ymbols F1, F2, F3, and F4. Bag rubbing or sand blasting will not be required on
formed surfaces. Grinding will not be required on formed surfaces, other than that
necessary for the repair of surface imperfections. Unless otherwise specified or indicated
on the drawings, the classes of finish which will apply are as follows .


       7.15.1.3.1 Finish F1- This finish is applied to surfaces where roughness is not
objectionable, such as those upon or against which fill material, masonry or concrete will
be placed, the upstream face of the dam that will permanently be under water or su rfaces
that will otherwise be permanenetly concealed. The surface treatment shall be repaired of
defective concrete, correction of surface depressions deeper than 25 mm and filling of tie
rod holes. Form sheathing shall not leak mortar when the concrete is vibrated. Forms may
be built with a minimum of refinement.


       7.15.1.3.2 Finish F2 - This finish is required on all permanently exposed surface for
which other finishes F3 and F4 are not specified; such as in outlet works and open
spillways, bridges and ret aining walls not prominently exposed to public view and in the
gallaries and adits in the dam, except where F1 finishes are permitted forms shall be built
in workmanlike manner to the required dimensions and alignment without conspicious
offsets of bulge s urface, irregularities, shall not exceed 5 mm for abrupt irregularities and
10 mm for gradual irregularities measured from a 1.5 m template.


       7.15.1.3.3 Finish F3 - This finish is designated for surfaces of structures
prominently exposed to public view whe re appearance is of special importance. This shall
include parapets, railings and decorative features on the dam and on the bridge. To meet
the requirements for the F3 finish, forms shall be built in a skillful, workmanlike manner,
accurately to dimensions . There shall be no visible offsets, bulges or misalignment of the
concrete. At construction




Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991     7/45



joints the forms shall be tightly set and securely anchored close to the joint. Surface
irregularities shall not exceed 3 mm for abrupt irregularities and 5mm for gradual
irregularities measured from a 1.5 m template.


       7.15.1.3.4 Finish F4 - This finish is required for for med concrete surfaces at the
spillway crest, glacis and bucket and inside sluices where accurate alignment and eveness
of surface are essential for prevention of destructive effects of water action. The forms


                                                                                          264
TECHNICAL SPECIFICATION


must be strong and held rigidly and accurately to the prescribed alignment. For warped
surfaces, the forms shall be built up in sections cut to made right, smooth form surface
after which the form surfaces are dressed and sanded to the required curvature.


      W hen measured as described in this clause, gra dual irregularities shall not exceed
5 mm. Abrupt irregularities will not be permitted. The formations of air holes on the
surface of the concrete designated to receive finish shall be minimised and where such air
holes are found, they shall be repaired in accordance with relevent section.


        7.15.2 Classes of Finish for Unformed Surfaces :


       7.15.2.1 General - The classes of finish for unformed concerte surfaces are
designated by the s ym bols U1, U2, U3 and U4. Unless otherwise specified or indicated on
the drawings these classes of finish shall apply as follows.


       7.15.2.2 Finish U1 - This finish applies to unformed surfaces that will be covered
by fill material, masonr y or concrete, or where a screeded surface finish meets the
functional requirements. Finish U1 is also used as the first stage of the Finishes for U2
and U3. Finishing operations shall consist of sufficient levelling and secreeding to produce
even uniform surfaces. Surface irregularities measured as described in this section shall not exceed
10 mm.


      7.15.2.3 Finish U2 - This is a floated finish and applies to all out door unformed
surface not specified to receive finishes U1 or U3. It may be used for such surfaces as of
spilways and aprons.


       Finish U2 is also used as the second stage of finish fo r U3. Floating may be
performed by use of hand or power driven equipment. Floating shall be started as soon as
the screeded surface has stiffened sufficiently to prevent the formation of laitence, and
shall be the minimum necessary to produce surface that is free from screed marks and is
uniform in texture. If finish U3 is to be applied floating shall be continued until a small
amount of mortar without excess water is brought to the surface, so as to permit effective
trowelling. Surface irregularities meas ured as described in this section shall be tolled
down where shown on the drawing or as directed.


       7.15.2.4 Finish U3 - This is a trowelled finish and may be specified for tops of
parapets prominently exposed to view, and conduit invert immediately d ownstream or
regulating gates and valves. W hen the floated surface has hardened sufficiently to prevent
excess of fine material from being drawn to the surface steel trowelling shall be started.
Steel trowelling shall be performed with firm pressure such a s will flatten the sandy
texture of the floated surface and produce a dense uniform surface free from blemishes
and trowel marks. Surface irregularities, measured as described in relevant part of this
section, shall not exceed 5mm.


W here a hard steel tro welled finish is specified the regular U3 finish shall be trowelled
again after the surface has nearly hardened using firm pressure and trowelling until the
surface is hard and has a slightly glossy appearance.



                                                                                                265
TECHNICAL SPECIFICATION


7.15.2.5 Finish U4 - This is a steel trowelle d finish similar to finish U3 except that light
surface pitting and light trowel marks such as obtained from the use of machine trowelling
or lining machines will be acceptable, provided the surface irregularities do not exceed the
limits specified for fin ish U3.
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       7.15.2.6 Unformed surfaces which are nominally level shall be sloped for drainage
as shown on the drawings or as directed. Unless the use of other slopes or level surface is
indicated on the drawings, narrow surface such as tops of parapets, tops of walls and
kerbs shall be sloped approximately one cm per 30 cm of width, broader surface such as
roadways, platform and decks shall be sloped approximately half centimetre per 30 cm of
width.
        7.16 REPAIRS OF CONCRETE :
       7.16.1 Genera l- Repairs of concrete shall be performed by skilled workers and in
the presence of the Engineer-in-charge. All imperfections on the concer te surface as
necessary to produce surfaces that conform with requirements of para 7.15 on formed
concrete shall be completed as soon as practicable after removal of forms and within 24
hours after removal of forms. Concrete that is damaged from any cause and concrete that
is honey-combed, fractured or otherwise defective and concrete which because of
excessive surface depressions excavated and built up to bring the surface to the
prescribed lines, shall be removed and replaced by dry pack mortar or concret e as
hereinafter specified. W here bulges and abrupt irregularities protrude outside the limits
specified in the para 7.15 “Finisies & finished of Concrete Surface”, the protrusions shall
be reduced by chiselling and grinding so that the surfaces are within the specified limits
       Dimantling of a part of hardened concrete of a structural element must not be done
by hammering since this is likely to crack adjoining good concrete. This should be done
slowly by pointed chisel or mechanically operated tool preferab ly by a skilled mason.
       Before repairs are commenced, the methods proposed for the repair shall be
approved by the Engineer-in-charge. Routine curing should be interrupted only on the area
of repair operations.
        7.16.2 Methods of Repairs - For new works four methods are used.
        7.16.2.1 Dry Pack Method - This method should be used for holes having a depth
nearly equal to or greater than the least surface dimensions; for cone bolt, she bolt and
grout insert holes and narrow slots cut for the repair of cracks. D ry packs should not be
used for relatively shallow depressions where lateral restraint cannot be obtained for
filling in back of considerable lengths of exposed reinforcements; nor filling holes which
extend entirely through the wall, beam, etc.
       7.16.2.2 Concrete Replacement Method - Concrete replacement should be used
when holes extend entirely through the concrete sections; when holes in unreinforced
concrete are more than 1000 sq.cm in area and 100 cm or more in depth; and the holes in
reinforced concrete are more than 500 sq.cm in area and deeper than the reinforcement
steel.
      7.16.2.3 Mortar Replacement Method -This should be used for holes too wide to
dry pack and too shallow for concrete replacement, and for all comparatively shallow
depressions, large and small which extend more deeper than far side of the reinforcement
bars nearest the surface.
      7.16.2.4 Epoxies Method - A thermosetting plastic known as epox y can be used as
a bonding medium wherever long time curing of conventional concrete cannot be assured.
Also epox y mortars of fine sand as well as plain epox y are suitable for concrete repair
work and should be used wh enever very thin patches are suitable for concrete repair work



                                                                                         266
TECHNICAL SPECIFICATION


and should be used whenever ver y thin pathes are to be placed for immediate re -use of
the area is required or where moist curing cannot be effectively accomplished. Preparation
for epox y bonded repairs should is general, be identical to that for other concrete repairs
except that ever y effort should be made to provide surfaces which are thoroughly dry.
Drying of the immediate surface for at least 24 hours and

warming to temperature between 18 o C to 27 o C are essential for proper application of
epox y bonded repairs. Preparation for the use of epox y




Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991   7/47



mortars should include thorough cleaning and drying of the areas to be repaired. A wash
of dilute 1:4 muriatic acid rinsing with clean water and subsequent drying is desirable
where feasible, if acid wash is not feasible, preparation may be accomplished as for other
concrete repairs with final clean up being by means of sand blast method, followed by air
water jet washing and thorough dr ying. Epox y repairs shall be carried out only by trained
personnel.


        7.16.3 Preparation of Concrete for Repair - All concrete of ques tionable quality
should be removed. It is better to remove too much concrete than too little because
affected concrete generally continues to disintegrate and while the work is being done it
costs but little more to dismantle to ample depth. Moistening, cl eaning, surface drying and
complete curing are of ulmost importance when making repairs which must be thoroughly
bonded, water tight and permanent. Surface between trimmed holes should be kept
continously wet for several hours preferably over night before placement of the filling, the
holes should be cleaned so as to leave a surface completely free of chipping dust, dried
grout and all other foreign materials. A preliminary washing as soon as the chipping and
trimming are completed is desirable to remove lo ose materials. W ashing by water jet is
useful to remove loose particles. Final cleaning of the surfaces to which the new concrete
is to be bonded should be done by wet sand blasting followed by washing with air -water
jet for thorough cleaning and dr ying wi th an air jet. Care should be taken to remove any
loose materials embedded in the surface by chissels during the trimming and to eliminate
all shiny spots indicating free surface moistures. Cleaning of steel if necessary should be
accomplished be sand blasting. The prepared surface shall be approved by the Engineer -
in-charge.
       7.16.3.1 Dry Pack of Concrete - For this method of repairs, the holes should be
sharp and square at the surface edges but the corners within the holes should be rounded,
especially when water tightness is required. The interior surfaces of holes left by cone
bolts, she bolts, etc., should be roughened to develop an effective bond. Other holes
should be under cut slightly in several places around the perimeter. Holes for dry pack
should have a minimum depth of 25 mm.
        7.16.3.2 Concrete Replacement - Preparation for this method should be as follows: -
      (a) Holes should have minimum depth of 100 mm in new concrete and the minimum
area of repair should 500 sq.cm for reinforced and 1000 sq.cm for unreinforced concrete.



                                                                                        267
TECHNICAL SPECIFICATION


      (b) The reinforcement bars should not be left partially embedded, there should be
clearance of atleast 25 mm around each exposed bar.
       (c) The top edge of the holes at the face of the structure should be cut to a fairly
horizontal line. If the shape of the defect makes it advisable, the top of the cut may be
stepped down and continued on a horizontal line. The top of the hole should be cut to 1 to
3 upward slope from the back towards the face of the wall or a beam. It may be necessary to fill the hole
from both sides in which case the slope of the top of the cut should be modified accordingly.
       (d) The bottom and sides of the hole should be cut sharp and approximately square
with the face of the wall, when the hole goes entirely through concrete section spalling or
feather edges shall be avoided by having chippers worked from both faces. All interior
corners should be rounded to a minimum radius of 25 mm.
       7.16.3.3 Mortar replacement -Guniting - W hen mortar gun is used with this
method, comparatively shallow holes should be flared outwardly at about 1:1 slope to
avoid inclusion of rebound. Corners within the holes should be rounded. Shallow
imperfections in new concrete may be repaired by mortar r eplacement if the work is done
promptly after removal of the forms and while the concrete is still green for instance, when
it is considered necessary to repair the peeled areas resulting from surface materials
sticking to steel forms and surface may be fi lled using mortar guns without further
trimming or cutting. W henever hand placed
Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991               7/48



mortar replacement is used, edges of chip ped out areas should be squared with the
surface leaving no feather edges.


         7.16.3.4 Use of Dry Pack Mortar - The surface after preparing should be thoroughly brushed with
a stiff mortar or grout-barely wet enough to thoroughly wet the surface after which the dry pack material
should be immediately packed into place before the bonding grout has dried. The mix of bonding grout is
to be 1:1 cement and fine sand mixed to a consistency like thick cream. Under no circumstances should
bonding coat be wet enough or applied heavily enough to make dry pack material more than very slightly
rubbery. Dry pack is usually a mix (dry volume of weight) of one part of cement to 1-1/2 parts of sand that
will pass a 1.18 mm IS Sieve. A mortar patch is usually darker than the surrounding concrete unless
special precautions are taken to match the colours. Where uniform colour is important white cement may
be used in sufficient amount to produce uniform appearance. For packing cone bolt holes a leaner mix of
1:3 or 1:3-1/2 will be sufficiently strong and will blend better with the colour of the wall. Only enough water
should be used to produce a mortar which when used, will stick together on being moulded into a ball by
slight pressure of hands and will not exclude water but will leave the hands damp. The proper amount of
mixing water and proper consistency are those which will produce a filling which is at point of rubbery
when the material is solidly placed. Dr y pack material should be placed and packed in layers
having a compacted thickness of about 10 mm. The surface of each layer should be
scratched to facilitate bonding with next la yer. One layer may follow another immediately
unless appreciable rubberiness developes, in which case work on the repair should be
delayed by 30 to 40 minutes. Under no circumstances should alternate layers of wet and
dry materials be used. Each layer shou ld be solidly compacted over its entire surface by
use of a hard wood stick and hammer. Much of the tamping should be directed at a slight
angle and towards the sides of the hole to assure maximum compaction in these areas.
The holes should not be overfilled and finishing may usually be completed at once by laying the flat side
of a hardwood pieced against the fill and striking it several good blows. If necessary, a few light strokes
with a rag sometime later may improve the appearance. Steel finishing tools should not be used and
water must not be used in replacement of concrete.




                                                                                                          268
TECHNICAL SPECIFICATION


       7.16.4 Procedure of Replacement of Concrete, Curing of Repairs etc. - All
procedures for replacement, use of epoxies and curing of repairs shall be according to the
provisions laid down herein before.


     7.17 Cooling of Concrete - Heat release during hydration of cement when large
masses of concrete are being produced, poses two different problems viz.


           (i)      The thermal stability of concrete; and

           (ii)     The cracking of concrete.


       The thermal stability is necessary for normal behaviour of the structure. So, suitable cooling
system is to be adopted in the dam concreting in order to rapidly achieve thermal stability.


      In order to control thermal stability arising out of the heat of hydra tion, the
placement temperature of concrete should be adopted as directed by the Engineer -in-
charge.


7.18 TOLERANCES FOR CONCRETE CONSTRUCTION :
        7.18.1 General - (i) Permissible surface irregularities for the various clsses of
concrete surface finishes sp ecified in the relevent portion of the section of “Finishes and
finishing of Concrete surfaces” are defined finishes and are to be distinguished from
“Tolerances” as described in this section. Deviations from the established lines, grades
and dimensions will be permitted to the extent set -forth in this clause, provided that lesser
tolerances than those tolerances set -forth in this clause, may be prescribed at site if such
tolerances are considered to impair the structural action or operational action or
operational function of the structure.
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       (ii) W here tolerances are not stated in the specifications or drawingsfor any
individual structure or feature thereof , permissible deviations will be interpreted in
conformity with the provisions of this clause.


       (iii) Concrete work that exceeds the tolerance limits specified in this section shall
be either remedied satisfactorily or removed.


       7.18.2    Mass Concrete in Dams and Appurtenant Works - The following
tolerances shall apply for concrete in dam and other larger mass concrete structures.


(i) (a)    Variation of the constructed linear out-       ...   In 6 metres.           ...   12 mm
           lines from established position in plan.       ...   In 12 metres.          ...   20 mm


     (b)   Variations of dimension to individual          ...   In 24 metres or more   ...   30 mm




                                                                                                     269
TECHNICAL SPECIFICATION



              structural feature for established            ...   In burried              ...   Twice the
              position.                                           construction.                 above amount.


(ii) (a)      Variations from the plumb, from the           ...   In 3 metres.            ...   12 mm
              specified batter or from the curved           ...   In 12 metres or more    ...   30 mm
              surfaces of all structures including          ...   In burried.             ...   Twice the
              the lines and surfaces of walls and                 construction.                 above amount.
              vertical joints.


       (b)    Variations from the level or from the         ...   In 3 metres.            ...   6 mm
              grades indicated on the drawings.             ...   In 9 metres or more     ...   12 mm
                                                            ...   In burried              ...   Twice the
                                                                  construction.                 above amount.


(iii) (a)     Variations in cross sectional dimensions...         Minus.                  ...   6 mm
              of columns, beams, butteresses,               ...   Plus.                   ...   12 mm
              piers and similar members and
              variation in the thickness of slabs,
              wall and similar members of concrete
              upto M25 strength.


       (b)    For concrete M35 and above                    ...   Minus.                  ...   3 mm
                                                            ...   Plus.                   ...   6 mm


(iv)          Variation from plumb and level for sills      ...   Not greater than a rate of
              and side walls for radial gates and           ...   3 mm in 3 metres.
              similar water tight joints.


             7.18.3 Placing Reinforcement Bars :


             The following tolerances shall apply for placing of reinforcement bars.


(i)           Variation of protective covering.             ...   Upto 50 mm cover        ...   3 mm

                                                            ...   Upto 75 mm, cover

                                                                  and over                ...   12 mm




                                                                                                                270
TECHNICAL SPECIFICATION



(ii)      Variation from indicated spacing of           ...   Variation upto 13 mm in spacing

          reinforcement.                                ...   either way is acceptable but total

                                                              area of steel in the component

                                                              is not reduced.




Volume I –Sec..IV          Specifications For Irrigation Projects Nov. 1991            7/50



       7.19 POROUS CONCRETE - Porous concrete shall be used at locations shown on
the drawings or as directed. Porous concrete shall be composed of one part of cement to
five and half part of aggregate by weight. The fines in the aggregate (viz. sand) may be
permitted upto ten percent of the total aggregate. Only so much water shall be used in the
concrete as is required to produce paste which will coat the particles and not fill the voids.
In placing porous concrete, care shall be taken to ensure that it is not over tamped or
compacted. The porous concerte as laid shall be pervious and free draining when it
hardens. As soon as the concrete hardens (so that, paste cannot be washed away) it
should be kept moist for a minimum of fourteen days. The compressive strength of porous
concrete at 7 days as determined by test on 15 cm by 30 cm cylinder should not be less
than 70 kg/cm2 and the porocity at 7 days be such that water shall pass through a slab of
the concrete 30 cm thick at a minimum rate of 500 litre/mm/sq. metres of the slab wit h a
constant 10 cm depth of water standing on the slab. The porous concrete blocks shall be
laid as shown in the drwaings or as directed by the Engineer -in-charge to form porous
drains in the masonr y dam.
        7.20 ST ANDARD OF ACCEPTANCE :


      7.20.1 General -The standard of acceptance will be the same whether it is “Nominal
Mix Concrete” or “Design Mix Concrete”. For relatively small and unimportant buildings
and works in which quantity of concrete is less than 15 cubic metre, the strength tests may
be waived by Engineer-in-charge at his discretion.
       Random samples from fresh concrete shall be taken as specified in IS: 1199 -1959
and cubes shall be made, cured and tested as described in IS: 516 -1959. If required for
some other purposes, for example, to estimate the t ime when the form work can be
stripped, tests may be conducted at early ages also but the acceptance or otherwise is
always on the basis of 28 days strength. The average of the strength of three specimens
is the test strength of any sample. The total numbe r of test results required to constitute
an acceptable record for calculation of standard deviation shall be not less than 30.
Attempts should be made to obtain the 30 test results, as early as possible, when a mix is
used for the first time. The calculati on of the standard deviation shall be brought uptodate
after every change of mix design and atleast once a month. W hen significant changes are
made in the production of concrete batches (for example changes in the materials used,
mix design, equipment or technical control), the standard deviation value shall be
separately calculated for such batches of concrete.


      W here sufficient test results for a particular grade of concrete are not available, the
value of standard deviation given in Table 17 may be assum ed.




                                                                                                   271
TECHNICAL SPECIFICATION




                                                   TABLE - 17
                                       Assumed Standard Deviation


                     Grade of Concrete                                  Assumed S.D. N / mm


                           M 10                       ...                      2.3

                           M15                        ...                      3.5

                           M20                        ...                      4.6

                           M25                        ...                      5.3

                           M30                        ...                      6.0

                           M35                        ...                      6.3

                           M40                        ...                      6.6




Volume I –Sec..IV           Specifications For Irrigation Projects Nov. 1991              7/51



       7.20.2 Determination of Standard Deviation - The Standard deviation of concrete
of a given grade shall be calculated using the following formula from the results of
individual tests of concrete of that grade obtained.

        Estimated standard deviation S            =          2
                                                       √ n-1
        W here,
         = Deviation of the individual test strength from the average strength of `n' samples, and


         n = Number of sample test results.


        7.20.3 ACCEPT ANCE CRITERIA :


        7.20.3.1 The concrete shall be deemed to comply with the strength requirements if:
         a)   Ever y sample has a test strength not less than the characteristic value; or




                                                                                                      272
TECHNICAL SPECIFICATION


         b)     The strength of one or more samples though less than the characteristic value,
               is in each case not less than the greater of : -


               (1) The characteristic strength minus 1.35 times the standard deviation; and


               (2) 0.80 times the characteristic strength, and the average strength of all the
                   samples is not less than the characteristic strength plus,


                       1.65                times the standard deviations

                (    no. of samples   )

        7.20.3.2 The concrete shall be deemed not to comply with the strength requirement
if.


        (a) the strength of any sample is les s than the greater of;


              (i)    the characteristic strength minus 1.35 times the standard deviation; and
              (ii) 0.80 times the characteristic strength; or


        (b)    the average strength of all the samples is less than the characteristic strengt
               plus;
                (1.65- 3          ) times the standard deviation.
                      no. of samples


       Concrete which does not meet the strength requirement as specified in 7.20.3.1
above but has a strength greater than that required by 7.20.3.2 may at the discretion of
designer, be accepted as being structurally adequate without further tests. If the concrete
is deemed not to comply persuant to 7.20.3.2, structural adequac y of the parts affected
shall be investigated and consequential action as n eeded shall be taken.


        7.20.3.3 Concrete of each grade shall be assessed separately.
        7.20.3.4 Concrete shall be assessed daily for compliance.
      7.20.3.5 Concrete is liable to be rejected if it is porous or honey combed; its placing
has been interrupted without providing a proper construction joint; the reinforcement has
been displaced beyond the tolerances specified; or construction tolerances have not b een
met. However, the hardened concrete may be accepted after carrying out suitable
remedial measures to the satisfaction of the Engineer -in-charge.
Volume I –Sec..IV             Specifications For Irrigation Projects Nov. 1991   7/5123



        7.21        FILLING FOUNDATIONS WITH M ATERIALS OTHER THAN



                                                                                                273
TECHNICAL SPECIFICATION


                    CEMENT CONCRET:
        7.21.1 Filling foundations with lime Concrete :


      7.21.1.1 Proportioning - The proportion of lime mortar shall be as specified in the
item of work and proportion of lime mortar and coarse aggregate shall be one of lime
mortar and two of the coarse aggregate, all by volume and measured in measuring boxes.
       7.21.1.2 Lime Mortar preparation - Lime mortar shall be prepared in accordance
with the specifications laid down under para 6.6.3 of Chapter 6 ‘Mortar’.
       7.21.1.3 Mixing - Coarse aggregate shall be free from all impurtities and if dirty or
dusty, should be thoroughly washed before being mixed with mortar. Concrete shall be
mixed on a level and impervious platf orm, with tight and close joints. Dimensions of the
platform shall be as directed by Engineer -in-charge.
       The coarse aggregate shall be spread on the platform in a heap of uniform depth . It
shall be wetted before mixing. The required quantity of mortar sha ll be spread over the
whole surface of the coarse aggregate also to a uniform depth. The material shall then be
thoroughly incorporated by being turned over and over, backwards and forwards not less
than three times, until ever y particle of the coarse aggr egate is fully coated with mortar.
Measuring boxes must be used for measuring both the aggregate and the mortar to ensure
use of the required proportion of mortar.


       No more concrete shall be mixed than can be laid to place and rammed the same
day. W hen it is necessary to give fluidity to concrete, this shall be effected by adding
water to mortar and to the mixed concrete.


      7.21.1.4 Form Work - Form work if necessary shall be as specified under para 7.8
and shall be removed only after concrete is set.


      7.21.1.5 Laying - Before placing the concrete the bed of the concrete shall be
cleaned of all loose stuff, moistened and rammed if necessary. Form work if used shall be
approved by the Engineer-in-charge before laying.


      Concrete shall be used while fresh. It shall be laid (and not thrown) in layers not
exceeding 15 cm to 20 cm in thickness.


       7.21.1.6 Compaction - Concrete shall be well compacted by ramming with wooden
or iron rammers with area or ramming not exceeding 320 sq.cm and weighing not less than
4.50 kg, before the next layer is laid. The consolidation shall continue for each layer until
the mortar creams upto the surface. No water or mortar shall be added during laying or
ramming. If after adequate ramming, the mortar does not fill the interstices of the
aggregate and creams upto the surface, the top surface should be groued with thin mortar.
No ramming shall be done after the concrete has begun to set. Ramming shall be done by
one or more lines of men, ranged across the width of concrete with a lat eral space of not
more than 45 cm per man. After consolidation the surface must be kept damp.


      If appreciable time passes between laying consecutive layers, the lower course
should be made rough, cleaned and watered before the upper layer is laid.



                                                                                         274
TECHNICAL SPECIFICATION




      After form work is removed, honey combed spots shall be finished with the lime
mortar of the type used in the concrete.


      7.21.1.7 Curing - All lime concrete is to be kept continuously wet for atleast 14
days after it has been deposited in position or until it is built over. The wetting shall be
done initially on signs of dr yness by spreading hessein or straw and watering very
frequently from
Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991   7/53




a watering can through a perforated rose in moderate quantity and later directly on
concrete after the mortar has set. All water used in mixing and curing of concrete shall be
clean and free for any injurious materials.


        7.21.2 Filling foundations with Excavated materials, Soil, Sand or Moorum :


       7.21.2.1 Preparation - The ground over which filling has to be done shall be
cleared of all grass, loose, stones, rubbish of all kind as well as tree roots, bushes etc. If
there is water it shall be pumped or bailed out.


       The excavated material if to be used for filling should be properly stacked as per
the direction of Engineer-in-charge and shall be cleaned of all the rubbish, large stones,
etc. and clods broken down to a size of 50 mm or less.


      Materials to be brought from out side i.e. sand, moorum or yellow soil shall also be
cleaned of all rubbish and shall be used only after the approval of the Engineer -in-charge.


       7.21.2.2 Laying - The approved soil, sand or moorum shall be laid in 15 to 20 cm
thick layers. Each layer shall be watered and compacted with heavy rammers before the
upper layer is laid, till the required level is reached so as to form a thoroughly compact
base.


     For filling in plinth, watering and compaction shall be done in such a way as not to
endanger the foundation columns, plinth wall etc., already built up.


      Under no circumstances black cotton soil or similar greatly expansive and
shrinkable soil shall be used for filling foundation or under the plinth.




                                                                                         




                                                                                          275
TECHNICAL SPECIFICATION




Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991           7/54




                                               APPENDIX - I


                                                (Para 7.3.1.4)


   Physical and Chemical requirements of Indian Standard Specifications for Different Cements


 Characteristic             Ordinary       Rapid          Low heat      High   Portland     Portland



                                                                                                       276
TECHNICAL SPECIFICATION



                              Portland    Hardening    Portland      strength      Pozzolana Slag
                              Cement,     Portland     Cement        Portland      Cement    Cement
                              (IS:269-    Cement       (IS:12600-    Cement        (IS:1489- (IS:455-
                              1976)       (IS:8041-    1989)         (IS:8112-     1976)      1976)
                                          1976)                      1976)
         1.                      2.         3.               4.        5.             6.          7.


Physical Requirements :

Fineness :


Specific surface (Cm 2/g.).   2,250      3,250        3,200         3,500        3,000      2,250

Setting time, vicat

Initial setting time (minutes), 30        30           60            30            30       30

Minimum


Final setting time (hours),      10       10           10            10            10       10

Maximum


Soundness :

Le-Chatelier method,            10a,      10a,         10a,          10a,          10a,     10a Expansion (mm),
Maximum                          5b,      5b,          5b,           5b,           5b,      5b,


Autoclave expansion,*

Percent, Maximum                0.8       0.8          0.8           0.8           0.8      0.8

Heat of hydration (cal/g).


Maximum


7 days                          ...       ...          65            ...           ......

28 days                         ...       ...          75            ...           ......


              d- where X is the declared percentage of pozzolana.
              e- Air- entraining or other agents which have proved not to be harmful.




                                                                                                        277
TECHNICAL SPECIFICATION


               f- Lime saturation factor = CaO - 0.7 SO3


                                             2.8 SiO2 + 1.2Al2O3 + 0.65 Fe2O3

               X- Declared percentage of pozzolana in the given Portland Pozzolana Cement.

               *- The test is to be performed if MgO>3 percent

                                                
                                      •••




Volume I –Sec..IV             Specifications For Irrigation Projects Nov. 1991      7/55




                                                   APPENDIX - II


                    Determination of Necessary Adjustment for Bulking of Fine Aggregate
                                                   (Field Method)


      1. Object - This method of test covers the field method for determining the
necessary adjustment for the bulking of fine aggregate.


       2. General - Sand brought on to a building site or other works may contain an
amount of moisture which will cause it, when loosely filled into a container, to occupy a
larger volume than it would occupy if dry. If the sand is measured by loose volume, it is
necessary in such a case to increase the measured volume of the sand, in order that the
amount of sand put into the concrete may be the amount intended for the nominal mix
used (based on dr y sand), it will be necessary to increase the volume of sand by the
“percentage” bulking. The correction to be made in only a rough approximation, because
the system of measurement by order volume is a rough method at the best, but a
correction of the right order can easily be determined and should be applied in order to
keep the concrete uniform.


        3. Procedure :




                                                                                             278
TECHNICAL SPECIFICATION


      3.1 The procedure to be adopted may be varied, but two methods, are suggested in
3.2 & 3.3. Both depend on the fact that the volume of inundated sand is the same as if the
sand were dr y.


       3.2 Put sufficient quantity of the sand loosely into a container until it is about two
thirds full. Level off the top of the sand and pushing a steel rule vertically down through
the sand at the middle to the bottom, measure the height suppose this is h cm.


       3.2.1 Empty the sand out of the container into another container where none of it
will be lost. Half fill the first container with water. Put back about half the sand and rod it
with a steel rod, about 6 m in diametre so that its volume is reduced to a minimum. Then
add the remainder of the sand and rod it in the same way. S mooth and level the top
surface of the inundated sand and measure its depth at the middle with the steel rule. Suppose this is
h” cm.


       3.2.2 The percentage of bulking of the sand due to moisture shall be calculated
from the formula.


                             Percentage bulking = (h / h” -1) x 100


        3.3 In a 250 ml measuring c ylinder, pour the damp sand (consolidated by shaking)
until it reaches the 200 ml mark. Then fill the cylinder with water and stir the sand well.
(The water shall be sufficient to submerge the sand completely). It will be seen that the
sand surface is now below its original level. Suppose the surface is at the mark Y ml. The
percentage of bulking of the sand due to moisture shall be calculated from the formula.


                          Percentage bulking = (200 / y - 1) x 100


      4. Reporting of Results - Report the percentage bulking of the sand to the nearest
whole number.



•••
Volume I –Sec..IV              Specifications For Irrigation Projects Nov. 1991             7/56




                                                    APPENDIX - III
                                              Physical Requirements
                                                      (Para 7.3.5)


Sl. No.   Requirement                                  Accelerating     Retarding   Water    Air-Entraining




                                                                                                              279
TECHNICAL SPECIFICATION



                                                  Admixture   Admixture   Reducing    Admixture
                                                                          Admixture
      1.       2.                                      3.       4.         5.           6.


i)         Water content, percent of control           -         -         95               -
           sample, Max.


ii)        Time of setting, allowable deviation from
           control sample, hours. Initial


                    Max.                               -3      +3           +1          -
                    Min.                               -1      +1
                    Final
                    Max.                               -2      +3           +1          -
                    Min.                               -1


iii)       Compressive strength, percent of
           control sample, Min :-


                    3 days.                            125     90           110         90
                    7 days.                            100     90           110         90
                    28 days.                           100     90           110         90
                    6 months.                          90      90           100         90
                    1 year.                            90      90           100         90


iv)        Flexural strength, percent of
           control sample Min.


                    3 days.                            110     90           100         90
                    7 days.                            100     90           100         90
                    28 days.                           90      90           100         90


v)         Length change, percent increase
           over control sample, Max :-




                                                                                                  280
TECHNICAL SPECIFICATION


                     28 days.                                  0.010             0.010               0.010            0.010
                     6 months.                                 0.010             0.010               0.010            0.010
                     1 year.                                   0.010             0.010               0.010            0.010


vi)           Bleeding, percent increase
              over control sample, Max :-                      5                 5                   5                2




                                                                                                                  •••




Volume I –Sec..IV                 Specifications For Irrigation Projects Nov. 1991                             7/57




                                                       APPENDIX - IV
                               Requirement for Concrete Exposed to Sulphate Attack


Class                Concentration of Sulphates                        Type of            Requirement for densefully
                     expressed as SO3                                  cement             compacted concrete made

                  In Soil                  In ground                                          with           aggregates             complying
          Total SO3 SO3 in 2:1             water (parts                                              with IS: 383-1970

        (percent)       Water extract per million)                                   Min. Cement                Max. Free /

        g / litre                                                                     content            water cement ratio


1.          2.               3.            4.             5.                             6.                      7.


1.      Less than       Less than           ...   Ordinary Portland Cement               280kg/m                0.55
        0.2             30                        or Portland Slag Cement
                                                  or Portland Pozzolana
                                                  Cement.


2.      0.2 to 0.5      30 to 120           ...   Ordinary Portland Cement               330                    0.50
                                                  or Portland Slag Cement



                                                                                                                              281
TECHNICAL SPECIFICATION



                                               or Portland Pozzolana
                                               Cement.


                                               Super Sulphated Cement             310   0.50


3.     0.5 to 1.0    120 to 250          ...   Super Sulphated                    330   0.50
       1.9 to 3.1                              Cement.


       Note 1- This table applies only to concrete made with 20 mm aggregate complying
with the requirements of IS: 383 - 1970* placed in near neutral grou nd waters of pH 6 to
pH9, containing naturally occuring sulphates but not contaminants such as ammonium
salts. For 40 mm aggregate the value may be reduced by about 15 percent and for 12.5
mm aggregate the value may be increased by about 15 percent. Concre te prepared from
ordinary portland cement would not be recommended in acidic conditions (pH6 or less).
Supersulphated cement gives an acceptable life provided that the concrete is dense and
prepared with a water/cement ratio of 0.4 or less, in mineral acid s, down to pH 3.5.
       Note 2 - The cement contents given in Class 2 are the minimum recommended. For SO 3
contents near the upper limit of Class 2, cement contents above these minimum are advised.
      Note 3 - W here the total SO 3 in col 2 exceeds 0.5 percent, then a 2:1 water extract
may result in a lower site classification if much of the sulphate is present as low solubility
calcium sulphate.


       Note 4 - For severe conditions such as thin sections under hydrostatic pressure on
one side only and sections partly immersed, considerations should be given to a further
reduction of water/cement ratio, and if necessary an increase in the cement to ensure the
degree of workability needed for full compaction and thus minimum permeability.
      Note 5 - Portland slag cement conforming to IS: 455 -1976 with slag content more
than 50 percent exhibits better sulphate resisting properties.
         Note 6 - Ordinar y portland cement with the additional requirement that C 3 A content
be not more than 5 percent and 2 C 3 A + C 4 AF (or its solid solution 4CaO, Al 2 O 3 ,
Fe 2 O 3 +2CaO, Fe 2 O 3 ) be not more than 20 percent may be used in place of
supersulphated cement.


Volume I –Sec..IV              Specifications For Irrigation Projects Nov. 1991         7/58




                                                    APPENDIX - V


                                       REQUIREMENTS FOR DURABILITY
                          Minimum Cement Content Required in Cement Concrete to
                          Ensure Durability Under Specified Conditions of Exposure


                                                                                               282
TECHNICAL SPECIFICATION




         Exposure                                          Plain concrete       Reinforced concrete


                                                           Mini.       Max.     Min.        Max.
                                                           cement      water    cement      water
                                                           content     cement   content     cement

                                                           Kg / m3     ratio    Kg / m3     ratio
         (1)                                                 (2)        (3)      (4)         (5)




Mild -     For example, completely protected against       220         0.7      250        0.65
           weather, or aggressive conditions, except
           for a brief period of exposure to normal
           weather conditions during construction.


Moderate - For example, exposed sheltered from             250         0.6      290        0.55
           heavy and wind driven rain and against
           freezing, whilst saturated with water; buried
           concrete in soil and concrete continuously
           under water.


Severe - For example, exposed to sea water, alter          310         0.5      360        0.45
           nate wetting and drying and to freezing
           whilst wet, subject to heavy condensation
          or corrosive fumes.




     Note-1 - W hen the maximum water-cement ratio can be strictly controlled the
cement content in the above table may be reduced by 10 percent.


      Note-2 - The minimum cement content is based on 20 mm aggregate. For 40 mm
aggregate, it should be reduced by about 10 percent; for 12.5 mm aggregate, it should be
increased by about 10 percent.



          •••




                                                                                                      283
TECHNICAL SPECIFICATION




Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991   7/59




                                              APPENDIX - VI
                             HOW TO BATCH CONCRETE BY VOLUME


       1. General - The proper & accurate measurement of all the materials used in
concrete making is necessar y to ensure uniformity of proportions & aggregate gra ding in
succeeding batches. W hen concrete is batched by volume there is always a danger of
variation between one batch and another. So if on any job batching is specified by volume,
a certain amount of extra care is required to make sure that quantities ar e correct.


        2. Gauging Cement - Cement is often gauged by volume but this is most
inadvisable except for small or unimportant jobs. The point against measuring cement by
volume (even when other materials are measured by vol.) is that it is difficult to sec ure
accuracy in as much as actual volume of a given weight of cement depends upon how it is
filled into the gauge box and whether it is shaken down. The density of cement may vary
from about 1.12 gm per cm 3 if it is lightly poured into the container to wel l over 160 gm
per cm 3 if tamped down sufficiently hard. Invariably, therefore, the size of the concrete
batch should be so determined as to require whole bags of cement, but should a fraction
of a bag be required it should be weighed into bucket suspended from an ordinary 50 kg
spring balance.


       3. Gauging Aggregates By Volume - Aggregate can be gauged by volume and for
this wooden batch boxes called ‘farmas’ are used.
      The size of the farmas should be such as to measure the correct quantity of
aggregates to be used with a whole bag of cement for the required mix. They should not


                                                                                       284
TECHNICAL SPECIFICATION


be made so large as to be unwieldy; it is preferable to have a farma that will contain, say,
half the required quantity of material, and to fill this twice over for each batch of concrete.
Convenient sizes are indicated in Table given below.
       The farma should made of 3 cm thick prepared timber, which gives a good strong
job. Joints should be tongued & grooved with the tongue on the inside of the box. This
prevents any dirt getting in if the joints should o pen through shrinkage or rough handing.
The faces of the joints should all be painted with red linseed oil before the farma is
assembled.


                                                    Sizes of Farmas


          Capacity litres                                     Inside measure
                                               Length                    Breadth   Height


                     litres                    cm                        cm        cm
                     25                        25                        25        40
                     30                        25                        25        48
                     35                        27                        27        48
                     40                        29                        29        48
                     45                        30                        30        50
                     50                        31                        31        52


       It is advisable to flash the top edge of the box with sheet metal to keep a clean
level edge for striking off. The handles should be shaped to provide an eas y grip.
       W hen a mixer machine is used on the job it will be convenient to have lips on the
sides of the farma which can then be rested on the mixer hopper when the contents are
being tipped in.


       Before concreting operations are started, the farma volumes should be checked
for specified quantities. W hen filling the farmas the material should be thrown loosely
into
Volume I –Sec..IV             Specifications For Irrigation Projects Nov. 1991          7/60



the box & struck off level; no compacting should be allowed. At the end of each day’s work
the farma should be stacked upside down to prevent any accumulation of rain water.


      4. Calculating Batch Volumes - A concrete mix is generally speci fied in parts by
volume, as for example 1:1-1/2:3, 1:2:4, etc. meaning one part of cement to so many part
of coarse aggregate. Since it is proposed to use only whole bags of cement these
proportions must be converted to suit this unit.




                                                                                               285
TECHNICAL SPECIFICATION


        Take a mix specified as 1:2-1/2:4. Now one 50 kg bag may be considered to hold 35
litres of cement, so above figures should be multipled by 35. The mix will therefore, be 50
kg of cement to 88 litres of sand to 140 litres of coarse aggregate.


        As these quantities of sand & aggregate are too large to be conveniently handled,
the next thing, in this case, would be to have a farma for the sand made up to hold half of
88 litres (30x30x49 cm) & fill it twice, & for the coarse aggregate a 35 litres farma, would
be filled four tim es. Farmas much larger than 50 litres in size are rather incovenient to
use.


        5. The Phenomena of Bulking - The figures given above are for dry sand but, the
sand as delivered and used on the job quite frequently contains moisture which causes
films of water to form on the surface of the particles, fluffing them apart. This is called
bulking and for a moisture c ontent of about 5 or 6 percent may be as much as 20,30 or
even 40% depending upon the grading of the sand, fine sands bulk much more than
coarse sands. Further addition of water tends to flood or pack the sand decreasing the amount of
bulking, and when the sand is completely inundated the volume is approximately the same as when
measured dry & loose.


        If allowance for bulking is not considered when batching by volume it will not only increase the
cost of concrete by reducing the yield per bag of cement, but it will also have an under sanded mix which
is harsh & difficult to place. An example given later will illustrate this point.


      6. Measurement of Water - Of even greater importance than the accurate
measurement of cement & aggregate is the proper control o f mixing water. The strength &
other desirable properties of a concrete mix depends entirely upon the quantity of water
used to the bag of cement, the concrete becoming weaker as more water is added just as
the cementing property of glue is impaired as it is mixed with more & more water.
       The prevalling method of gauging water “by the eye” with any odd tin can, direct
into the mixer is most inaccurate & can not be too strongly condemned.
       The mix design gives together with the specified mix, the exact quantit y of mixing
water to be used, as to many litres per 50 kg of cement. An exact 5 litre measure is used
to calibrated any other containers. This will ensure that the correct amount of mixing water
is added to the concrete mix.
      For determining surface moistur e, table 15 and for determining absorption by
aggregate following table can be used : -
                                                    TABLE
                                Approximately Absorption of Aggretate


       S.No        Aggregate.                                  Percent by weight


       (i)         Average sand.                       ...     1 Percent


       (ii)        Gravel and crushed lime stone.      ...     1 Percent




                                                                                                    286
TECHNICAL SPECIFICATION


       (iii)        Trap rock and granite.                     ...        0.5 Percent


       (iv)         Porous sand stone.                         ...        7.0
       (v)          Very light and porous aggregate.           ...        25.0
Volume I –Sec..IV              Specifications For Irrigation Projects Nov. 1991         7/61




         The method of using these tables will be vler from the following example :

         Example : Materials per batch

                          50 kg of cement

                            88 litres of sand (saturated, surface -dry).

                          175 litres of coarse aggregate.


         The Engineer has specified 25 litres of water to be used per 50 kg of cement.


      Correction for moisture - Suppose the sand used is moderately wet (surfac e
water 65 gm per litre See table 15) and the coarse aggregate is also moist (surface water
30 gm per litre).


         Then total surface water carried by the aggregate is ;


                            sand = 65 x 88        = 5,720 gm,


         Coarse aggregate = 30 x 175 = 5,250 gm,


                                                     = 10,970 gm say 11 litres.


       Since this water is introduced into the mix with the aggregates, it must be deducted
from the 25 litres specified by the E ngineer, that, is to say, only 14 litres must be actually
added to the batch at the time of mixing.


        If neglected to make this correction, the concrete mix would have contained 36
litres per 50 kg of cement, causing a considerable reduction in its strength .


      Correction for absorption - It not infrequently occurs in our hot climate that the
sand and coarse aggregate being used is bone -dry & will actually absorb water from the
concrete, thus reducing the water cement ratio.




                                                                                               287
TECHNICAL SPECIFICATION



      Suppose the sand used weighes 1.60 gm per cm 3 when dry (absorption 1.0 percent
by weights, see Table on pre-page). The coarse aggregate is trap rock and weighs 1.44
gm per cm 3 (absorption 0.5 percent by weight).


        Then the total water absorbed by the aggregate is;


                          Sand = 1 x 88 x 1.60     = 1.41 kg
                                      100


         Coarse aggregate = 0.5 x 175 x 1.44 = 1.26 kg
                                            100
                                                    Total = 2.67 Kg say 2.7 litres
        This quantity must be added to the 25 litres specified by the Engineer, that is to say
27.7 litres must be added to the batch at the time of mixing.


       Loss of water by Evaporation - In very hot dry weather it often happens tha t some
of the water contained in the concrete mix is lost by evaporation during transporting &
placing. An allowance may be made for this by a corresponding increase in the amount
added at the mixer, prior approval of the Engineer having been obtained.


      Summary - The precautions that must be observed in the batching of concrete by
volume can be summed up in a series of don’ts.




Volume I –Sec..IV          Specifications For Irrigation Projects Nov. 1991          7/62




       (i) Don’t gauge cement by volume except for the most unimportant jobs. Determine
the size of your batch so as to require whole bags of cement, but should a fraction of a
bag be required weigh the cement into a bucket suspended from an ordinary 50 kg spring
balance.


      (ii) Don’t gauge aggregates into any old container. Have special farmas made on
each job, carefully calculating their dimensions to suit the field mix proportions.


        (iii) Don’t make farmas larger than about 50 litres otherwise they become unwieldy.
It is preferable to use a farma which contains, say, half the required quantity & fill it twice
over.




                                                                                            288
TECHNICAL SPECIFICATION


      (iv) Don’t compact aggregate into the farma when filling them in. The aggregates
should be loosely thrown into the box & struck off level.


       (v) Don’t neglect to make allowance for bulking of sand, if any. Use the bulking test
to determine the correct volume of damp sand that should be batched., which will be more
than the volume of dr y sand specified in the mix.


     (vi) Don’t gauge water “by the eye” with any odd tin can direct into the mixer.
Measure the water carefully into a calibrated container.


       (vii) Don’t neglect to make allowance for the moisture that may already be present
in aggregates when gauging mixing water.

•••




                                                                                        289
TECHNICAL SPECIFICATION




Volume I –Sec..V              Specifications For Irrigation Projects Nov. 1991           8A/1



                                                   CHAPTER - 8A
                              Stone Masonry and Precast Block Masonry Work
                                         (Other than Masonry in Dams)
8A.1 SCOPE:
        8A.1.1 This chapter covers the specifications for construction of stone masonry for:
          (i)      Building
          (ii)     Hydraulic structures with maximum height 10 m (from lowest foundation level, and
          (iii)    Precast block masonry.
       8.A.2 This chapter does not cover the specifications for masonry for dams and
hydraulic structures more than 10 m height for which specifications of Chapter 8B shall
apply.
8A.2 REFERENCES :
       IS : 269-1989              - Ordinary portland cement, 33 Grade (fourth revision).


       IS : 383-1970              - Coarse and fine aggregates from natural sources for concrete (second
                                    revision) (Reaffirmed 1980).


       IS : 455-1976              - Portland slag cement (third revision) with amendment nos. 1 to 6).


       IS : 456-1976              - Code of practice for plain and reinforced concrete (third revision)
                                    (with amendment no.1).


       IS : 1121                  - Methods of test for determination of strength properties of natural
                                    building stones.


       IS : 1121 (Pt.l)-1974      - Compressive strength (first Revision (with amendment no.1) Reaffirmed
                                    1987.


       IS : 1121 (Pt.ll)-1974     - Transverse strength (first Revision) (Reaffirmed 1987).




                                                                                                         290
TECHNICAL SPECIFICATION


       IS : 1124-1974           - Method of test for determination of water absorption apparent specific
                                  gravity and porosity of natural building stones (first revision).
       IS : 1127-1970           - Recommendations for dimensions and workmanship of natural building
                                  stones for masonry work (first revision) (Reaffirmed 1987).
       IS : 1129-1972           - Recommendations for dimensions and workmanship of natural building
                                  stones for masonry work (first revision) (Reaffirmed 1987).


       IS : 1489-1976           - Portland pozzolana cement (second revision) (with amendment nos. 1to
                                  6).


       IS : 1597-1967           - Code of practice for constructiom of stone masonry.


       IS : 1957 (Pt.l)-1967    - Rubble stone masonry.


       IS : 1597 (Pt.ll)-1967   - Ashlar masonry (Reaffirmed 1987).


       IS : 1805-1973           - Glossary of terms relating to stones : Quarrying and dressing (first
                                  revision) (Reaffirmed 1987).


       IS : 2185                - Concrete masonry units.


       IS : 2185 (Pt l.)-1979   - Hollow and solid concrete (second revision) (with amendment no.1)
                                  (Reaffirmed 1987).


Volume I –Sec.V            Specifications For Irrigation Projects Nov. 1991              8A/2




       IS : 2185 (Pt.ll)1983    - Hollow and solid lightweight concrete blocks (first revision).


       IS : 2402-1963           - Code of practice for external rendered finishes.


       IS : 2645-1975           - Integral cement water proofing compounds (first revision) (with
                                  amendment no. 1) (Reaffirmed 1987).


       IS : 3812-1981           - Fly ash for use as pozzolana and admixture (first revision).


       IS : 6042-1969           - Code of practice for construction of light weight concrete block masonry.


       IS : 6909-1973           - Supersulphated cement (with aendment nos. 1 to 3 ).




                                                                                                       291
TECHNICAL SPECIFICATION




       IS : 8041-1978        - Rapid hardening portland cement (first revision) (with amendment nos 1
                               to 3).


       IS : 8042-1978        - White portland cement (first revision with ammendment nos.1 to 5).


       IS : 8043-1978        - Hydrophobic portland cement (first revision (with amendment nos. 1 to
                               3).


       IS : 9103-1979        - Admixtures for concrete.


       IS : 9394-1979        - Stone lintels (reaffirmed 1987).
                             - C.P.W.D. Specifications 1977, Volume l.
                             - All India standard schedule of Rates - 1977.
                               1. Standard Specification of National Building Organisation.
                                2. Building Research Note no. 7 of Central Building Research
                          Institute, India “Precast Stones Masonry Block Walliing Scheme”.
                                    - Maharashtra Specifications.
8A.3 TERMINOLOGY :


      Ashlar - Stone masonry using dressed square stone blocks of given dimensions
having faces perpendicular to each and laid in courses.


        Bed joint - The joint where one stone presses on another for example, a horizontal
joint in a wall or a radiating joint between the voussoirs of an arch (see Figure 8 -A/1)*.
        Bond - An interlocking arrangement of structural units in a wall to ensure stability.
      Bond Stone (Through Stone) - Selected long stones used to hold a wall together
transversally (See Figure 8-A/2)*.
       Corbel - Stone bonded well into the wall with part of it projecting out of the face of
wall to form a bearing surface.
      Cornice - A horizontal moulded projection which crowns or finishes either a wall,
any horizontal division of wall, or any architectural feature (See Figure 8 -A/3A)*.
        Courses - A layer of stones in a wall including the bed mortar.
       Cramp - A small piece of metal or the hardest or toughes t stone procurable, sunk in
mortices and fixed across joints as additional ties. The ends of metal cramps are bent at
right angles and stone cramps are dovetailed (See Figure 8 -A/3B)*.
       Dowels - Dowels are small sections of metal, stone or pebbles bedded wi th mortar
in corresponding mortice in bed or side joints of adjacent stones (See Figures 8 -A/3C)*.




                                                                                                    292
TECHNICAL SPECIFICATION


Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991   8A/3



        Hammer Dressing - Rough surfacing to a stone by means of a small hammer.


        Jamb - The part of the wall at the side of an opening.


      Joggle - A key between the stones by providing a groove in one stone to take a
corresponding concealed projection in the edges on the other sto ne (See Figure 8-A/3B)*.


        Natural Bed - The plane of stratification that occurs in sedimentary rocks.


      Parapet - A solid or pierced guard wall to flat terrace or a balcony (or a bridge) or a
curb wall at the lower part of a pitched roof, which is exposed to atmosphere on face, back
and top (See Figure 8-A/3A)*.


       Quoin - A quoin is the external angle of a wall of bui lding. The term is also applied
to a stone specially selected and neatly dressed for forming such angle.


        Random - Of irregular sizes and shapes.


        Reveal - The part of the jamp between the frame and the arris.


      Rubble Masonry - Masonr y built of stones eith er irregular in shape as quarried or
squared and only hammer dressed and having comparatively thick joints. Stones for rubble
masonry are, as for as possible, angular.


       String Course - A horizontal band, plain or moulded, usually projecting slightly
from the face of a wall (See Figure 8 -A/3A)*.


       Template or Bed Block - A block of stone or concrete bedded on a wall to
distribute the pressure from a concrete load.


      Plum Stone (Pin-Header) - Selected long stones embedded vertically in the interior
of masonry wall to form a bond between successive courses.


       Efflorescence - A powder y encrustment of salt left by evaporation. This may be
visible on the surface or may be below surface.


        Hearting - The infilling which forms the core of a rubble wall.




                                                                                         293
TECHNICAL SPECIFICATION


8A.4 Uncoursed Rubble Masonry / Random Rubble / Polygonal Faced Masonry:
8A.4.1 Materials.
        8A.4.1.1 Stone - The stone shall be of the specified variety (such as granite,
trapstone, sand stone, quartzite etc). The stone shall be obtained only from an approved
quarry and shall be hard, sound, durable and free from defects like cavities, cracks, sand
holes, flaws, injurious veins, patches of loose or soft materials etc. Stone with round
surface shall not be used. The stone should not contain crypto-crystalline silica or chert, mica or any
other deleterious material like iron oxide, organic impurities, etc. The water absorption shall not be more
than 5 percent when tested in accordance with Appendix -A. The minimum crushing strength of stone
shall be 200 kg/sq.cm unless higher minimum strength is specified in any particular case. All stone shall
be obtained by quarrying large massive rock unless otherwise specified.
       8A.4.1.1.1 Size of Stone - Normally stones used in rubble masonry should be small
enough to be lifted and placed by hand. The length of the stone shall not be less than its
height and shall not exceed three times the height; and the breadth on base shall not be
less than its height and shall not be greater than three -fourths of the thickness of the wall
nor less than 15 cm. The height of stone of Rubble masonry may be upto 30 cm and shall
not be less than 22.5 cm for hydraulic structures and 15 cm in other cases
Volume I –Sec.V           Specifications For Irrigation Projects Nov. 1991            8A/4

        .
      8A.4.1.2 Mortar - The mortar used shall be cement mortar/lime morta r/lime
pozzolana mortar/cement lime mortar/cement surkhi mortar of specified proportion or mud
mortar. The detailed specifications for mortar given under chapter 6 “Mortar” shall apply.


        8A.4.2 Dressing of Stones - Face stones used for uncoursed or random rubble
masonry work shall be hammer dressed on the sides and beds in such a way as to close
up with th e adjacent stone in the masonry work as strongly as possible. The face stones
shall be dressed in such a manner as to give specified pattern such as polygonal facing,
etc. The face of stones shall be so dressed that bushing on the exposed face shall not
project by more than 40 mm from the general wall surface and on the face to be plastered
it shall not project by more than 10 mm nor shall it have depressions more than 10 mm for
the average wall surface. The hearting or interior filling shall be constructed of stones as
they come from the quarr y and no dressing shall be done except cutting of the stones to
the removal of inconvenient corners with a scabbling of spalling hammer.
8A-4.3 Laying :
       8A.4.3.1 All stones shall be sufficiently wetted before laying to prevent absorption
of water from mortar. The wall shall be built truly plumb (or true to required batter when so
specified). All connected walls in a structure shall normally be raised up uniformly and
regularly. However, if for any specified reason, one part of the masonry is required to be
left behind, the wall shall be raked back at and angle not steeper than 45 degrees.
Toothed joints in masonr y shall not be allowed.
      The work shall be carried up regularly and masonry on any day shall not be raised
by more than one metre in height.
        8A.4.3.2 Stones shall be laid in an uncoursed fashion, or to produce specified
pattern such as polygonal facing, random facing etc. However, the masonry is required to
be brought to level at various stages viz. plinth level, window sill level, lintel level, roof
level and any other level specifically shown in the drawing. This may be done by firstly
adjusting the laying of stones to one level and then by providing a 40 mm thick levelling
course of cement 1:6:12 (1 cement:6 sand:12 graded stone aggregate of 20 mm nominal
size). If more thickness of levelling course is required, then richer mix shall be used as specified by the
Engineer-in-charge.


                                                                                                      294
TECHNICAL SPECIFICATION


        8A.4.3.3 Proper bonding shall be achieved by closely filling in adjacent stones as
well as by using bond stones as described herein below. Face stones shall extend back
sufficiently and bond wel l with the masonry. The stones shall be carefully set so as to
break joints and avoid formation of vertical joints. The depth of stone from the face of the
wall inward shall not be less than the height or the breadth at the face.
        8A.4.3.4 All stones shall be carefully laid, hammered down by a wooden mallet into
position and solidly embedded in mortar, chips of stone may be used wherever necessary
to avoid thick mortar beds or joints, at the same time ensuring that no hollow space is left
anywhere in the masonr y. The chips shall not be used below hearting stones to bring
these upto the level of face stones. The use of chips shall be restricted to the filling of
interstices between the adjacent stones in hearting. The chips used shall not be more than
20% by volume of masonr y, and in the case of random rubble masonry or polygonal faced
masonry no spalls or chips shall be seen on the exposed face. The hearting shall be laid
nearly level with face stones except that at about one metre intervals vertical band ston es
or plums projecting about 150 to 200 mm shall be firmly embedded to form vertical
bonding in masonr y.
       8A.4.3.5 Bond Stones - Bond stones or through stones running right across the
thickness of the wall shall be provided in walls upto 600 mm thick. In th icker walls upto 2
m bond stones of length not less than 2.5 times the height of the course shall be provided
over lapping each other by at least 150 mm. There shall be at least one bond stone for
every 0.5 sq.m of wall surface. The bond stones shall be ma rked by a distinguishing letter
during


Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991   8A/5



       construction for subsequent verification; and shall be laid staggered in subsequent
layers. In walls thicker than 2 m through bond stones are not required to be provided.
However bond stones as specified above are required to be provided for face masonry.
W here bond stones of suitable length are not available cement concrete block of 1:3:6
(1cement:3 coarse sand:6 graded metal 20 mm size) conforming to size mentioned above
shall be used.
       8A.4.3.6 Plum Stones - Plum stones 45 cm long or depth of two courses which
ever is more shall be provided in hearting at the rate of one for every square metre of area
in plan. For every course a new set of headers shall be introduced at this rate in a
staggered pattern. The average sectional area of each should not be les s than 0.03 sq.m.
       8A.4.3.7.Quoins - The quoins or corner stones shall be selected stones neatly
dressed with hammer and/or chisel to form the required corner angle and laid header and
stretcher alternately. No quoin stone shall be smaller than 0.03 cu.m in volume and it shall
not be less than 300 mm in length; 25% of them being not less than 500 mm in length.
       8A.4.3.8 Jamb Stones - The jambs shall be made with stones specified for quoins
except that the stones provided on the jambs shall have their equal to the thickness of the
wall for walls upto 600 mm and a line of headers shall be provided for walls thicker than
600 mm as specified for bond.
       8A.4.3.9 Joints - All joints shall be conmpletely filled with mortar and their width
shall not exceed 20 mm in fac e masonry, and 35 mm in hearting masonry. W hen plastering
or pointing is not required to be done the joints shall be struck flush and finished
simultaneouly while laying the stones. Otherwise the joints shall be raked to a minimum
depth of 20 mm by a raking tool during the progress of laying while the mortar is still
green.
        This type of masonr y is illustrated in Figure No. 8 -A/2*



                                                                                        295
TECHNICAL SPECIFICATION


        8A.4.4 Scaffolding - Single or double scaffolding shall be used. The scaffolding
shall be strong and sound. The holes left in masonry for supporting scaffolding shall be
filled and made good before plastering.


       8A.4.5 Curing and Protection - Green work shall be protected from rains by
suitably covering the same. Masonry in cement mortar or composite mortar shall be kept
constantly moist on all the faces for a period of at least seven days. The top of masonry
shall be flooded at the close of the day. In case of fat lime mortar (with or without
pozzolana) curing shall commence two days after laying of masonry and shall continue for
seven days.
8A.5 COURSED RUBBLE MASONRY FIRST SORT/COURSED RUBBLE MASONRY                                      SECOND
     SORT:
      8A.5.1 Materials - Same as for uncoursed rubble masonry/random rubble/polygonal
faced masonr y described under paras 8A 4.1.1 and 8A 4.1.2.
        8A.5.2 Dressing of Stones:
        8A.5.2.1 For first sort coursed rubble masonry face stones shall be hammer
dressed on all beds and joints so as to give them approximately rectangular shape. These
shall be square on bed and side joints. The bed joints shall be rough chisel dressed for a
depth of at least 75 mm back from the face, and the side joints shall be dressed to a depth
of at least 40 mm back from the face, such that no portion of the dressed surface is more
than 6 mm from a straight edge held against the surface. The remaining porti ons of the
respective surfaces shall not project above the chisel dressed bed and side joints. The
bushing on the face shall not project by more than 40 mm on an exposed face and 10 mm
on a face to be plastered.


* For Figure please           refer    to    the    original     Specifications   published   by   E-in-C,
W .R.Deptt.,Bhopal.




Volume I –Sec.V           Specifications For Irrigation Projects Nov. 1991             8A/6



       8A.5.2.2 For second sort coursed rubble masonry the stones shall be dressed as for
first sort masonr y described in para 8A.5.2.1 above except that no portion of dressed
surface shall show a depression of more than 10 mm (as against 6 mm for first sort) from
the straight edge placed against the dressed surface.
        8A.5.3.1 Laying:
        8A.5.3.1 Coursed Rubble Masonry First Sort:
       8A.5.3.1.1 All stones shall be wetted before laying. The wall shall be built up truly
plumb (or to required batter where so specified). All connected masonry in a structure
shall normally be raised up uniformly and regularly . However, if for any specific reasons
one part of wall is required to be left behind such wall shall be raked back at an angle not
steeper than 45 degrees, toothed joints in masonry shall not be allowed. The work shall be


                                                                                                      296
TECHNICAL SPECIFICATION


carried up regularly and masonr y on any day will not be raised by more than 1 metre in
height.


       8A.5.3.1.2 All courses shall be laid truly horizontal. The height of course shall not
be less than 150 mm nor more than 300 mm. However, the course height shall be uniform
throughout the height of masonr y. Face stones shall be laid in alternate header and
stretcher fashion. They shall be so arranged as to break joints by at least 75 mm. Stones
shall be laid with grains horizontal so that the load is transmitted along the direction of
their maximum crushing strength. The depth of stone from the face of wall inwards shall
not be less than the height. The breadth of a face stone shall also be not less than the
height. Each face stones shall be of the same height in any given course.


       The courses shall be built in perpendicular to the pressure which the masonry will
bear. In case of battered walls, (such as retaining walls) the beds of stone and the plane
of course shall be laid with their bed perpendicluar to the battered face.


        8A.5.3.1.3 The hearting or the interior filling of the wall shall consist of flat bedded stones carefully
laid on their proper beds in mortar, chips and spalls of stone being used where necessary to avoid
excessive use of mortar, care being taken to see that no hollow space is left any where in the masonry.
Chips shall not be used below the hearting stone to bring these upto the level of face stones. The use of
chips shall be restricted to filling of interstices between the hearting stones but the volume of chips shall
be limited to 10% of the total volume of masonry.
      8A.5.3.1.4 Bond Stones - Bond stones shall be provided in the same manner as in
the case of uncoursed rubble masonry described in para 8A.4.3.5 above except that in this
case there shall be at least one bond stone for 1.5 m to 1.8 m length of every course.
      8A.5.3.1.5 Plum Stones (Pin Headers) - Specifications shall be the same as
described in para 8A.4.3.6.
       8A.5.3.1.6 Quions - The quions, which shall be of the same height as the course to
which it belongs shall be formed from selected stone at least 450 mm length. They shall
be laid square on bed as stretchers and headers alternatively. The beds shall be rough
chisel dressed to a depth of at least 100 mm. These stones shall have a minimum uniform
chisel drafts of 25 mm width at four edges, all the edges being in the same plane.
        8A.5.3.1.7 Joints - Except in case of battered wall all bed joints shall be horizontal and all side
joints shall be vertical. Face joints shall not be more than 10 mm thick for first sort and 15 mm for second
sort masonry. All joints shall be properly and completely filled with mortar. On faces where no plastering
nor pointing is required to be done, the joints shall be struck flush and finished simultaneously while
laying the stones. In other case, the joints shall be raked to minimum depth of 20 mm by raking tool
during the progess of work while the mortar is still green.
        This type of masonr y is illustrated F igure No. 8-A/ *


* For Figure please            refer     to   the    original     Specifications   published       by   E -in-C,
W .R.Deptt.,Bhopal.




Volume I –Sec..V            Specifications For Irrigation Projects Nov. 1991                8A/7




                                                                                                            297
TECHNICAL SPECIFICATION


       8A.5.3.2 Coursed Rubble Masonry Second Sort - This type of masonry shall be
constructed in the same manner as first sort masonry described above, except that no
portion of dressed surface of joint shall show a depth of gap more than 1 cm from a
straight edge placed on it and the use of chips for fill ing of interstices shall be limited to
15% of the total volume of masonr y and that it is permissible to have courses of varying
heights. A course may be made up of single stones or two stones.


        8A.5.4 Other Details - The specification for curing, protection and scaffolding shall be the same
as for uncoursed rubble/random rubble masonry described in para 8A.4.4 and 8A4.5.


8A.6 Hammer Dressed Coursed Rubble Masonry :


      8A.6.1 Materials - Same as for uncoursed rubble masonry as described in para
8A.4.1.1 and 8A.4.1.2.


       8A.6.2. Dressing of Stones - Face stones shall be hammer dressed on all beds
and joints so as to give them approximately rectangular shape. The bed and side joints
shall be hammer dressed for 75 mm from the face. The bushing on the face shall no t be
more than 4 cm on the exposed face.


        8A.6.3 Laying - For laying provision under para 8A.5.3.1 shall be followed.


        8A.6.4 Bond Stones - These shall be provided as specified in para 8A.5.3.1.4.


        8A.6.5 Plum Stones (Pin Header) - These shall be provided as specified in para 8A.4.3.6.


        8A.6.6 Quions - These shall be provided as specified in para 8A.5.3.1.6.


       8A.6.7 Joints - Provisions as specified in para 8A.5.3.1.7. shall be followed except
the thickness of face joint shall be 20 mm.


      8A.6.8 Scaffolding, Curing and Protection - The provisions made in para 8A .4.4.
and 8A. 4.5 shall be followed.


8A.7 STONE WORK IN PLAIN ASHLAR MASONRY:


      8A.7.1 Materials - Materials to be used for ashlar masonry shall be the same as
provided in para 8A.4.1.1 and 8A. 4.1.2.
        8A.7.2 Dressing of Stones:
      8A.7.2.1 Dressing - Ever y stone shall be cut to the required size and shape, chisel
dressed on all beds and joints so as to be free from bushing. Dressed surface, shall not
show a depth of gap of more than 3 mm from straight edge placed on it. The exposed



                                                                                                    298
TECHNICAL SPECIFICATION


faces and joints, 6 mm from the face shall be fine tooled so that a straight edge can be
laid along the face of the stone in contact with every point. All visible angles and edges
shall be true and square and free from chippings. The corner stones (quions) shall be
dressed square and corner shall be straight and vertical.
      8A.7.2.2.2 A sample of dressed stone shall be prepared & kept on the work after
approval from the Engineer-in-Charge.
        8A.7.3 Laying :
      8A.7.3.1. Stones shall be wetted before placing in position. They shall be floated on
mortar and bedded properly and solidly in position with a wooden mallet.
       8A.7.3.2 The wall shall be built truly vertical (or true to required batter as
specified). Stones shall be laid in alterna te header- stretcher fashion. The headers shall
be arranged in such a fashion so as to bring them centrally over the stretchers below
and above stones


Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991           8A/8



shall break joints on the face for at least half the height of the course and the bond shall
be carefully maintained throughout. The work shall be carried up regularly and masonry
on any day will not be raised by more than one metre in height.
         8A.7.3.3 The height of courses in a masonry work shall be uniform and shall not be less than 300
mm unless otherwise specified. The width of stone shall not be less than height or less in length than
twice its height unless otherwise directed by the Engineer-in-charge.
      8A.7.3.4. All connected masonry shall be raised uniformly and regularly throughout
but when a break is inevitable the joint shall be made in good long steps to avoid cracks.
       8A.7.3.5 W hen necessar y, jib crane or other mechanical appliances shall be used
to hoist heavy pieces of stones and place them in correct position. They shall be handled
carefully to avoid damage to edges and corners (which are more vulnerable to damage).
No damaged stone shall be allowed t o be used in work.
       8A.7.3.6 A masonr y work may be a composite one consisting of ashlar stone facing
with backing of either brick work, uncoursed rubble/coursed rubble masonry etc. In such
cases the two portions shall be carefully bonded. The above specifi cation shall apply to
face work and the backing shall be governed by the appropriate specifications applicable
to the type of backing used.
        This type of masonr y is illustrated in Figure No. 8 -A/4*.
       8A.7.3.7 Bond Stones - Bond stone shall be provided in the same manner as in
para 8A.5.4. In case of composite masonry (8A.7.3.6 above), the bond stones shall run
right across the combined thickness of the wall.
       8A.7.3.8 Joints - All joint shall be uniform throughout and not more than 6 mm
wide. A uniform recess of 15 mm depth from the face shall be made with the help of a
steel plate to receive pointing to be done later.
        8A.7.4 Pointing - All exposed joints shall be pointed using mortar with admixture of pigment to
match the shade of stone as specified. The pointing when finished shall be sunk from stone face by 5 mm
or as specified. The depth of mortar in pointing shall not be less than 10 mm.
      8A.7.5. Curing and Protection - The masonry shall be cured in the same manner
as described in para 8A.4.5. The work shall be suitably protected from damage during construction.




                                                                                                    299
TECHNICAL SPECIFICATION


       8A.7.6 Scaffolding - Double scaffolding shall be adopted. Single scaffolding shall
not be allowed. The scaffolding shall be built sufficiently strong and sound keeping in view
the heavy load of solid stones and other materials likely to be carried by it.
8A.8 ASHLAR ROUGH TOOLED OR PUNCHED MASONRY:
       8A.8.1 Dressing of Stone - The dressing of stone blocks shall be similar to plain
ashlar except that face exposed in view shall have a fine chisel draft 2.5 cm wide round
the edges and shall be rough tooled between the draft such that the dressed surface shall
not deviate more than 3 mm from the straight edge placed over it.
      8A.8.2. The requirements regarding laying, pointing, curing and scaffolding shall be
the same as for plain ashlar masonry.
8A.9 ASHLAR ROCK OR QUARRY FACED MASONRY:
       8A.9.1. Dressing of Stone - The dressing of stone blocks in case of ashlar rock
shall be similar to ashlar rough tooled except that the exposed faces of the stone
between the


* For Figure please          refer     to   the    original     Specifications   published    by   E -in-C,
W .R.Deptt.,Bhopal.




Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991             8A/9



drafts shall be left rough as the stone comes from the quarry; but no rock face or
“bushing” shall project more than 7.5 cm, from plane of drafts.




      8A.9.2. The requirements regarding laying, pointing, curing and scaffolding shall be
the same as for plain ashlar masonr y.


8A.10 DRY RANDOM RUBBLE MASONRY :


8A.10.1. Materials:


      8A.10.1.1 Stone - The stone shall conform in all respects to specifications under
para 8A.4.1.1. The stone shall not be less than 15 cm in any direction except the packing
stone. The face stones average breadth shall not be less than the height and average




                                                                                                       300
TECHNICAL SPECIFICATION


length not less than one and a half times the height for stones upto 20cm height & not less than one and
one third times the height or 30 cm whichever is more, for stones exceeding 20 cm in height.


      8A.10.1.2 Bond Stones - The bond stones shall run right across the wall a nd shall
not be less than 300 sq.cm in cross section at any point. In masonry wall thicker than 60
cm two bond stones over lapping each other by at least 150 mm may be used in
conjunction. The bond stones shall be provided @ 2 per square metre of front fac e area.
      8A.10.1.3 The stones shall be knocked off so as to obtain as large bedding surface
as possible.
      8A.10.1.4 The thickness of joint of the front and rear face shall not be more than 30
mm at any point.
8A.10.2 Laying :
       8A.10.2.1 The stones in the fou ndations shall be the longest available and shall be
laid close to each other and packed by hand. The front and back stones shall be laid
alternately as headers and stretchers as far as possible. The stones in the hearting shall
be laid interlocking each other. The stones shall break joints with the stones below.


      8A.10.2.2 The bond stones shall be in a line from front to back over lapping each
other at least 20 cm. The courses shall be built perpendicular to the pressure which the
masonry will bear. In cas e of battered (such retaining walls), the beds of stone and the
plane of course shall be laid with their bed at right angles to the battered face.
8A.11 PRECAST CEMENT CONCRETE BLOCK MASONRY :
        8A.11.1 Material :
      8A.11.1.1 Cement - Cement complying with any of the Indian Standards, IS:269 -
1989,    IS:455-1976 IS:1489-1976, IS:6909-1973, IS:8041-1978, IS:8042-1978 and
IS:8043-1978 (amended from time to time) may be used at the discretion of the
manufacturer.
       W hen cement conforming to IS:269-1989 is used, replacement of cement by fly ash
conforming to IS:3812 (Part 1) -1981 may be permitted upto a limit of 20%. However, it
shall be ensured that blending of fly ash with cement is as intimate as possible, to achieve
maximum uniformity.
      8A.11.1.2. Aggregates - The aggregates used in the manufacture of blocks at the
mixer or the mixing platform shall be clean and free from deleterious matter and shall
conform to the requirements of IS:383 -1970.


       The grading of the combined aggregates shall conform as near as possible t o the
requirements indicated in IS:383-1970. It is recommended that the fineness modulus of
the combined aggregates shall be between 3.6 and 4.0.




Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991          8A/10



                                                                                                    301
TECHNICAL SPECIFICATION




       Fly ash conforming to IS:3812 (Part lll) -1981 may be used for part replacement of
fine aggregate upto a limit of 20%.
       8A.11.1.3 Water - The water used in the manufacture of concrete masonry units
shall be free from matter harmful to concrete or reinforcement, or matter likely to cause
efflorescence in the units and shall conform to the requirements of IS:456 -1978.


       8A.11.1.4 Additives or Admixtures - Additives or admixtures may be added either
as additives to the cement during manufacture, or as admixtures to the concrete mix.
Additives or admixtures used in the manufacture of concrete masonry units may be :


          a)     accelarating, water-reducing and air-entraining admixtures conforming to
                 IS:9103-1979.


          b)     fly ash conforming to IS:3812(part-ll)-1981.


          c)     waterproofing agents conforming to IS:2645 -1975, and


          d)     colouring pigments.


       W here no Indian Standards apply, the additives or admixtures shall be shown b y
test or experience, to be not detrimental to the durabili ty of the concrete.
        8A.11.2 Dimensions :
       8A.11.2.1 Concrete masonr y building units shall be made in sizes and shapes to fit
different construction needs. They include stretcher, corners, double corner or pier, jamb,
header, bull nose, partition block and c oncrete floor units.
       8A.11.2.2 Concrete Block - Concrete block, hollow (open or closed cavity) or solid
shall be refered to by its nominal dimensions. The term “nominal” means that the
dimensions includes the thickness of the mortar joint. Actual dimensions shall be 10 mm
short of the nominal dimensions (or 6mm short in special cases where finer jointing is
specified).
        The nominal dimensions of concrete block shall be as follows :
        Length = 400,500 or 600 mm.
        Height = 200 or 100 mm.
        W idth = 50, 75, 100, 150, 200, 250 or 300 mm.
      In addition, block shal l be manufactured in half lengths of 200, 250 or 300 mm to
correspond to the full lengths.
       The nominal dimensions of the units are so designed that taking account of the
thickness of mortar joints, they will produce wall lengths and heights which will conf orm to
the principles of the modular coordination.
8A.11.3 Classification :




                                                                                         302
TECHNICAL SPECIFICATION


      8A.11.3.1 Hollow (Open and Closed Cavity) Concrete Blocks - The hollow (open
and closed cavity) concrete blocks shall conform to the following three grades.
       (a) Grade A - These are used as load bearing units and shall have a minimum block
density 1500 kg/m 3 . These shall be manufactured for minimum, average compressive
strengths of 3.5, 4.5, 5.5 and 7.0 N/mm 2 respectively at 28 days.


        (b) Grade B - These are also used as load bearing units and shall have a block




Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991   8A/11



density less than 1500 kg/m 3 , but not less than 1000 kg/m 3 . These shall be manufactured
for minimum average compressive strength of 2.0, 3.0, 5.1 N/mm 2 respectively at 28 days.


       (c) Grade C - These are used as non-load bearing units and shall have a block
density less than 1500 kg/m 3 , but not less than 1000 kg/m 3 . These shall be manufactured
for minimum average compressive strength of 1.5 N/mm 2 at 28 days.
      8A.11.3.2. Solid Concrete Blocks - Grade D The solid concrete blocks are used as
load bearing units and shall have a block density not less than 1800 kg/m 3 . These shall be
manufactured for minimum average compressive strengths of 4.0 and 5.0 N/mm 2
respectively.


8A.11.4 Manufacture:
        8A.11.4.1 Mix.
      8A.11.4.1.1 The concrete mix used for blocks shall not be richer than one part by
volume of cement to six parts by volume of combined aggregates before mixing.
       8A.11.4.1.2 In case of hand-moulded blocks where compaction is done manually,
concrete mix should be sufficiently consistent to enable demoulding immediately after
casting. The consistency of mix should be such that it may cohere when compressed in
the hand without free water being visible. Too little water causes the mix to be friable,
while too much water causes difficulty in the immediate withdrawal of the mould.
      8A.11.4.1.3 In case of machine-moulded blocks, the web markings on the units as
they come from the machine give a good indication as to whether the proper consistenc y
of concrete has been used. In addition to the grading of the aggregate and the quantity of
cement, the amount of water required for mix will depend to an e xtent on the type of
machine on which blocks are produced. It is possible to judge the proper consistenc y by
squeezing a handful of concrete mixture. W hen traces of moisture show on the outside of
the squeezed mass it is usually considered to be suitable.




                                                                                         303
TECHNICAL SPECIFICATION


        8A.11.4.2 Mixing :


        8A.11.4.2.1 Concrete shall normally be mixed in a mechanical mixture.


      (a) Mixing shall be continued until there is a uniform distribution of the materials,
and the mass is uniform in colour and consistenc y.


        (b) W hen hand mixing is permitted by the Engineer-in-charge, it shall be carried
out on a water-tight platform and care shal l be taken to ensure that mixing is continued
until the mass is uniform in colour and consistency. 10% extra cement may be added when hand-
mixing is restored to.


        8A.11.4.3 Placing and Compaction :


      8A.11.4.3.1 In the case of manual compaction, the mixture shall be placed into the
mould in layers of about 50 to 75 mm and each layer thoroughly tamped with suitable
tamper until the whole mould is filled up and struck off level with a trowel.
       8A.11.4.3.2 In the case of mechanical compaction, the mould shall be filled up to
overflow, vibrated or mechanically tamped and struck off level.
        8A.11.4.3.3 After demoulding, the blocks shall be protected until they are
sufficiently hardened to permit handling without damage.
        8A.11.4.4 Curing :


      8A.11.4.4.1 The blocks hardened in accordance with para 8A.11.4.3.3 shall then be
cured in curing water tank or curing yard, and shall be kept continuously moist for at least
14
Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991   8A/12



days. W hen the blocks are cured in immersion tank, the water of the tank shall be
changed at least ever y four days.


       8A.11.4.4.2 Steam curing of blocks hardened in accordance wit h para 8A.11.4.3.3
may be adopted instead of methods specified in para 8A.11.4.4.1 provided the
requirements of pressure or non-pressure steam curing are fulfilled.


      8A.11.4.5 Drying - After curing, the blocks shall be dried for a period of four weeks
before being used on the work. They shall be stacked with voids horizontal to facilitate
through passage of air. The blocks shall be allowed to complete their initial shrinkage
before they are laid in a wall.


        8A.11.5 Surface Texture and Finish:




                                                                                         304
TECHNICAL SPECIFICATION


        8A.11.5.1 Concerte masonr y units can be given a variety of surface textures
ranging from a very fine close texture to a coarse open texture by the proper selection,
grading, and proportioning of aggregate at the time of manufacture. Texture may also be
developed by treating the face of the units, while still green, by wire brushing or combing,
by slightly eroding the surface, by placing a fine spray of water upon it, and by splitting
(split block). Colour may be introduced by incorporating non -fading mineral pigments in
the facing concrete, or by applying a coloured cement grout or paint to the face of the
units soon after they are removed from the moulds. Selected coloured aggregates may
also be used in the facing and exposed by washing with water or dilute hydrochlori c acid.


        8A.11.5.2 W ell made concrete masonry may not require plaster in case of
unimportant buildings in low rainfall areas; two or three coats of a cement paint being
sufficient to render it resistant to rain water.If, However, it is intended to plaster concrete
masonry, the block shall have a sufficiently rough surface to afford a good key to the
plaster. W ater proofing admixtures may be used for preparing the plaster.
        8A.11.6 Mortar :
      8A.11.6.1 Cement lime sand mortar, cement sand mortar or lime pozzolana sand
mortar etc., as specified shall be used. Detailed specifications for mortars given under
Chapter-6 “Mortars” shall apply.


       8A.11.6.2 Mortar shall not be spread so much ahead of the actual laying of the
units that it tends to stiffen and loose its plasticity, thereby resulting in poor bond. For
most of the work, the joints, both horizontal and vertical shall be 10 mm thick. Except in
case of extruded joint construction, the mortar joints s hall be struck off flush with wall
surface and when the mortar has started stiffening, it shall be compressed with a rounded
or U-shaped tool. This compaction is important, since mortar, while hardening, has a
tendenc y to shrink slightly and thus pull away from the edges of the block. The mortar
shall be pressed against the units with a jointing tool after the mortar has stiffened to
effect intimate contact between the mortar and the masonry unit and obtain a water tight
joint.
        8A.11.7 Laying :
       8A.11.7.1 The blocks need be wetted before or during laying in the walls. In case
climatic conditions so require, the top and the sides of block may only be slightly
moistened so as to prevent absorption of water from the mortar and ensure the
development of the required bond with the mortar.
       8A.11.7.2 Operations of laying of precast cement concrete block masonry shall be
carried out as under.
       8A.11.7.2.1 First Course - The first course of concrete block masonry shall be laid
with great care, making sure that it is p roperly aligned, levelled and plumbed, as this may
assist the mason in laying succeeding courses to obtain a straight and truly vertical wall


Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991   8A/13.



       8A.11.7.2.1.1 Before laying the first course, the alignment of the wall shall be
marked on the damp-proof course. The blocks for this course shall first be laid dry, that is
without mortar along a string streched between properly located corner of the wall in order
to determine the correct position of the blocks including those of the cross walls jointing it
and also adjust their spacing. W hen the blocks are set in proper position, the two corner
blocks shall be removed, mortar bed spread and these blocks laid back in p lace truly level


                                                                                           305
TECHNICAL SPECIFICATION


and plumb. The string shall then be stretched tightly along the faces of the two corner
block and the faces of the intermediate ones adjusted to coincide with the line. Thereafter,
each block shall be removed and relaid over a bed of morta r. After every three or four
blocks have been laid, their correct alignment, level and verticality shall be carefully
checked.


        8A..11.7.2.2 The construction of walls may be started either at the corners first or
started from one end proceeding in the othe r direction. If the corners of the wall are built
first, they shall be built four or five courses higher than the centre of the wall. As each
course is laid at the corner, it shall be checked for alignment and level and for being
plumb. Each block shall be carefully checked with a level or straight edge to make certain
that the faces of the block are all in the same plane. This precaution is necessry to ensure
truly straight and vertical walls.


      8A.11.7.2.2.1 The use of a storey-rod or course pole which is simply a board with
markings 200 mm apart, provides an accurate method of finding the top of the masonry for
each course. Each course, in building the corners, shall be stepped back by a half -block
and the horizontal spacing of the block shall be checked b y placing a mason’s level
diagonally across the corners of the block.


       8A.11.7.2.3. W hen filling in the wall between the corners, a mason’s line shall be
streched from corner to corner for each course and the top outside edge of each block
shall be laid to this line. The manner of handling or gripping the blocks shall be such as
position the block properly with minimum adjustment.


       8A.11.7.2.3.1 To assure satisfactory bond, mortar shall not be spread too far ahead
of actual laying of the block as it will st iffen and lose its plasticity. As each block is laid,
excess mortar extruding from the joints shall be cut off with the trowel and thrown back on
the mortar board to be reworked into the fresh mortar. If the work is progressing rapidly,
the extruded mortar cut from the joints may be applied to the vertical face shells of the
block just laid. If there be any delay long enough for the mortar to stiffen on the block the
mortar shall be removed to the mortar board and reworked. Dead mortar which has been
picked up from the scaffold or from the floor shall not be used.
       8A.11.7.2.4 Closer Block - W hen installing the closer block, all edges of the
opening and all four edges of the closer block shall be buttered with mortar. The closer
block shall be carefully lower ed into place. If any mortar falls leaving an open joint, the
closer block shall be removed, fresh mortar applied and the operation repeated.
       8A.11.7.3 Quions and Closers - Special quion blocks (with a return face equal to
length to half the normal face) s hall be cast for all building and slabs for external work.
Proper half length closers shall be cast and not cut from full size blocks. The returned
ends of blocks for door and window reveals and quions shall be finished with a fair face in
the moulds.
       8A.11.8 Scaffolding - Only double scaffolding shall be used. The scaffolding shall
be strong and sound. No holes in the masonry for supporting shall be allowed.
        8A.11.9 Finishing :
       8A.11.9.1 The precast concrete block walls shall be suitably finished or pointed as
explained in Chapter 11 “Plastering and Pointing”.




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TECHNICAL SPECIFICATION




Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991          8A/14



      8A.11.9.2 Rendering and other finishes for different types of concrete blocks shall
be carried as under:-


        8A.11.9.2.1 External Renderings - Lightweight concrete blocks are alamost
invariably not impervious and will become damp when exposed to rain. T he exterior
surface of all lightweight concrete blocks shall, therefore, be made waterproof by treating
the wall with different types of renderings as explained below depending upon the intensity of rainfall,
nature of exposure of other seasons. Some other points that should be considered are given below:-
     (a) Renderings shall not be applied to the walls when these are wet or in monsoon.
The walls shall be treated only after they are dried.


        (b) Satisfactor y performance of any rendering depends entirely on the efficienc y of
the bond developed between the rendering and the wall surface. Extreme care shall,
therefore, be taken to ensure effective bond with the wall by preparing the surface,
cleaning the surface of all loose particles and dust, and lightly mois tening it with water
just prior to applying the rendering to prevent absorption of water from it.


        (c) The plaster finishes shall be applied in accordance with IS:2402 -1963.


        (d) The sand used for the plaster finish shall be graded from 3 mm downwards. The plaster shall
not be finished smooth, but provided with a coarse finish by means of a wooden float.
       8A.11.9.2.1.1 In localities where rainfall is heavy or the walls are exposed to sea
weather concrete block masonr y shall be rendered with two coats of plas ter. First coat
(backing coat)shall be of 15 mm thickness of 1:1:6 cement lime sand mortar or 1:6 cement
sand mortar. Second coat (finishing coat) shall be of 5 to 10 mm thickness of 1:1:6 to
1:2:9 cement lime sand mortar or 1:6 Cement Sand mortar.


       8A.11.9.2.1.2 In moderate rainfall areas, concrete block masonry shall be rendered
with at least one coat of 10 to 15 mm thickness of 1:1:6 cement lime sand mortar (or 1:6
cement sand mortar) or two coats of cement paint may be applied directly on concrete
block masonr y to provide a reasonable impervious surface to withstand rain.
       8A.11.9.2.1.3   In areas of scarce rainfall, where it is desired from aesthetic
considerations, the exterior surface of concrete block masonry need only be pointed with
1:1:6 cement lim e sand mortar or 1:6 cement sand mortar.
       8A.11.9.2.1.4 W here for architectural or other reasons it is necessary to have the
concrete block surface exposed, the walls shall either be built with block having richer
facing mixture or treated with two -coats of approved quality of cement based paint. In
either case the walls in heavy or moderate rainfall areas shall be pointed with 1:3 cement
mortar.
       8A.11.9.2.2 Internal Renderings - As machine made concrete block are of uniform
size, walls built with them prov ide an even surface. W here it is desired to have the block
surface exposed, the walls may only be flush pointed and painted with an approved quality
of cement paint, emulsion paint or chlorinated rubber paint. Oil based paints are liable to
be attacked by alkali from the blocks and mortar. Otherwise the interior surface on walls


                                                                                                    307
TECHNICAL SPECIFICATION


shall be plastered with one coat of 6 to 12 mm thickness of 1:2:9 cement lime sand mortar
or 1:6 cement sand mortar. W here a very smooth finish is desired, a second, coat of 2 to 3
mm thickness of lime finish may be applied.
8A.12 PRECAST STONE BLOCK MASONRY:
       8A.12.1 Materials- Stone Masonry Blocks - These shall be precast with concrete
of specified mix and stone 5 to 15 cm in size. Care should be taken that stone content in
the block is around 30% by volume.


        The stones shall be of specified variety such as granite, trap stone, sand stone,


Volume I –Sec.V           Specifications For Irrigation Projects Nov. 1991                    8A/15



quartzite, etc. These shall be obtained only from an approved quarry or approved river
boulders and shall be hard, sound, durable and free from all defects.


      The materials used for concrete shall conform to relevant specifications given in
para 8A.11.1 The size of blocks shall be as follows:


                                     Nominal Size (cm.)                      Actual Size (cm.)


                                        L      B        C                      L     B   H


        For Load Bearing walls.         30     20      15                      29    19 14


        For Partitions.                 30     10      15                      29    9   14


      Blocks of one-third and two-third of above sizes shall be used for bond purposes.
The minimum average compressive strength of blocks shall be 50 kg/cm 2 .


       The blocks shall be cast as per CBRI Technical Note No.7. The various steps in
casting are as follows:


      (i) Apply oil (grease and kerosene oil 1:4 ratio) on casting platform and place the
moulds in row.


       (ii) Arrange large size stone 12 cm size or so inside the mould, generally two or
three stones will be laid.
      (iii) Fill up the gaps between the stone pieces in the lower portion of the mould up
to a height of about 5 cm with cement concrete of mix 1:5:8 (1 cement : 5 sand : 8 stone
aggregate 20mm nominal gauge)/cement concrete:1:5:10 (1 cement:5 sand:10 stone
aggregate 20 mm nominal gauge) and compacted by trowel. The cement concrete should
have low water cement ratio so as to give a stiff mix.


                                                                                                      308
TECHNICAL SPECIFICATION


       (iv) Fill up the remaining portion by placing 60 to 75 mm pieces in gaps and again
pour the same cement concrete mix upto top and compact by/roding/tamping/vibrating.
     (v) The demoulding is done after 3 to 4 minutes of casting the block by butting a
wooden piece on top of the block cast and pulling th e mould up.
       (vi) The next day of casting, the block are turned upside down and stone texture
kept exposed. The blocks are removed and cured with water for two weeks and air dried
for 3 weeks before using in masonr y.


      8A.12.2 Mortar - The cement lime sand m ortar, cement sand mortar, lime
pozzolana sand mortar etc. as specified shall be used. Detailed specifications for mortars
given under relevant Chapter 6"Mortars” shall apply.


       8A.12.3 Laying - The blocks shall be slightly wetted before or during laying in the
wall, one-third and two-third size blocks shall be used for completing the bond. The
thickness of joints shall be 1 cm and it shall be ensured that all horizontal and vertical
joints are completely filled with mortar without any void left in the mason ry. The face joints
shall be raked to a depth of 1 cm by raking tool during the process of the work while the
mortar is still green so as to provide proper key for plaster or to facilitate pointing to be
done later. W here plaster or pointing is not require d, the joint shall be struck flush and
finished side by side.
      8A.12.4 Curing - Green work shall be protected from rains by suitable covering.
Masonry work in cement or composite mortar shall be kept constantly moist on all the
faces for a minimum period of seven days. In case of fat lime mortar curing shall
commence two days after the laying of masonry and shall continue for seven days.


Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991      8A/16



        8A.12.5 Scaffolding - Single or double scaffolding may be used. The scaffolding
shall be strong and sound. In case if single scaffolding is used, the holes shall be carefully
made good as per directions of the Engineer -in-charge.


        8A.13. Stone Shelves, Plain Copings, Cornices, String Courses and Sills :


       8A.13.1 Stone used for shelves, copings, cornices, String courses, shall be of the
specified variety and shall be hard, sound, durable and of uniform colour and texture.


        8A.13.2 Dressing - All exposed plane surfaces and sides shall be chisel dressed
such that the dressed surface shall not vary by more than 1 mm at any point from a 600
mm long straight edge placed against it except in the case of shelves where a variation of
3 mm shall be allowed. All visible angles and edges shall be free from chippings. The
surface to be burried in masonr y shall be rough chisel dressed. Copings, cornices and
sills shall be finished
to the shape as shown in the drawing. The finished thickness of stone shelves shall be as
specified with a permissible tolerance of 2 mm.




                                                                                           309
TECHNICAL SPECIFICATION


      8A.13.3 Laying and Fixing - Laying and fixing of these items shall be done in
cement mortar of specified mix, in the manner shown in the drawing and as directed by the
Engineer-in-charge.


      8A.13.4 Other Details - Pointing, curing, protection, scaffolding etc., shall be done
as specified for plain ashlar masonry work vide para 8A. 7.4, 8A.7.5 and 8A.7.6.


8A.14 STONE LINTELS :


      8A.14.1 Lintels are important structural part of a building. The strength of the stone
used for lintels is of considerable importance, and therefore, due care should be taken
while making their selection.


       8A.14.1.1 General Requirements - The stone for the lintels shall be reasonably
fine grained, hard and shall h ave a uniform texture and colour. They shall be free from
weathering and decay. The stone shall be without any cracks, vents, fissures, clay holes
or other similar source of weakness.


       The lintel shall be so cut that when set in the building, the stone is laid on its
natural bed or with the bed in the same direction as it was when the test for transverse
strength was carried out.


      8A.14.2 Physical Properties - The physical properties of the stones used for lintels
shall conform to the requirements given in Col. 3 of Table below, when tested in
accordance with provisions of Indian Standards given in Col. 4.


                                                     TABLE
                            Physical Properties of stones used for lintels


   Sl.No.     Characteristics                  Requirements                  Method ofTest(Ref.to IS)
         1         2                                    3                            4

   (i)        Specific gravity.                ...    2.6 Min       ...   IS:1124-1974
  (ii)        W ater absorption,precent, ...          1.0 Max. ...        IS:1124-1974

   (iii)      Transverse strength, N/mm 2 ... 11.00 Min.... IS:1121(Part ll) - 1974


       8A.14.3 Dimensions and Tolerance - The stone lintels shall be of rectangular
cross-section. The width shall be equal to the thickness of the wall and the depth shall not
be less than 100 mm. The length shall be limited to a maximum cl ear span of 2.65 metres.
A tolerance of ±1.5 mm shall be allowed on all dimensions of 1.2 m or less and ±3 on all
dimensions more than 1.2 m.


Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991                  8A/17



                                                                                                        310
TECHNICAL SPECIFICATION




       8A.14.4 Lintel Bearing - Stone lintels shall be well bonded into the masonry on
either side of the opening. The bearing length on either side shall not be less than the
depth of the supporting masonr y whichever is more. The beari ng length shall be increased
for exceptionally heavy loads and for long spans. Bed blocks shall be provided if the clear
span exceeds 2 m.


       8A.14.5 Workmanship - The edges of the stone lintels shall be dressed as
specified in respective masonries. The expo sed surface of the lintel shall be finished as
specified.


        8A.15 STONE CHAJJA :


       8A.15.1 Stone Slabs - Stone slabs shall be of specified variety and shall be hard,
sound and durable. They shall be chisel dressed on all faces which are exposed to view
and rough dressed at other surfaces. Angles shall be true and edge lines straight. The
finished thickness shall be as stipulated with a permissible tolerance of 2 mm. The length
of stone slabs shall not be less than 60 cm unless otherwise specified.


       8A.15.2 Slopping Chajja - The slope, projection etc. shall be as indicated in
drawing. The bearing on the wall being similarly sloped. The chajja shall have a minimum
bearing of 20 cm on the wall, measured horizontally. Each slab shall be anchored down by
means of a steel bar 12 mm in diameter and 450 mm long, the lower end being bent for
mixing into the masonry joint. The steel bar shall pass through the hole drilled in the
centre of the stone slab.


       8A.15.3 Horizontal Chajja - The stone shall be fixed horizontally with a slight outer
slope of about 1:20. Holding down bolt shall be provided where so specified. The stone
chajja shall have a minimum bearing of 20 cm.


       8A.15.4 Other Details - The specification for curing, protection, scaffolding,
pointing etc.shall be t he same as for stone work in plain ashlar masonry detailed under
paras 8A.7.4, 8A.7.5 and/or as specified in the work.




                                   -------------------------------




                                                                                        311
TECHNICAL SPECIFICATION




Volume I –Sec V           Specifications For Irrigation Projects Nov. 1991   8A/18



                                                 APPENDIX-A
                             TEST FOR WATER ABSORPTION OF STONE
                                                (Para 8A.4.1.1)


       1.Selection of Samples - The sample shall be selected to represent a true average
of the type or grade of stones under consideration.


      The sample shall be selected from the quarried stone or taken from the natural rock
as described below and shall be of adequate size to permit the preparation of the requisite
number of test pieces.


       Stone from ledge or quarr y face of the stone shall be inspec ted to determine an y
variation in different strata. Differences in colour and structure shall be observed.
Separate samples of stone weighing at least 25 kg each of unweathered specimens shall
be obtained from all strata that appear to vary in colour and s tructure. Pieces that have
been damaged by blasting shall not be included in the sample.


       Field Stone and Boulders - A detailed inspection shall be made of the deposits of
field and boulders over the area where the supply is to be obtained. The different k inds of
stone and their conditions in the various deposits shall be recorded. Separate samples
shall be selected of classes of stone that would be considered for use in construction as
indicated by visual inspection.



                                                                                        312
TECHNICAL SPECIFICATION




     W hen perceptible variations occur in t he quality of rock, the purchaser shall select
as many samples as are necessar y for determining the range in properties.


       2. Test Pieces - The test pieces selected as above shall be crushed or broken and
the material passing 20 mm IS Sieve and retained on 10 mm IS Sieve shall be used for the test.


        3. Apparatus :


        Cylindrical Measuring - A jar of 1000 ml and 100 ml capacity shall be used.
        Glass Jars                    The 100 ml capacity jar shall have graduation mark of 1 ml.


        Glass Vessel                  - A vessel of about 1.5 litre capacity and two dry
                                         absorbent clothes of 0.5 sq.m area each.


        Balance                       - of capacity 3 kg with an accurac y of 1 gm.


        Desiccator :
        Oven:
       4. Procedure - The test piece weighing about 1 kg shall be washed to rem ove
particles of dust and immersed in distilled water in a glass vessel at room temperature 20 o
to 30 o C for 24 hours. Soon after immersion and again at the end of soaking period,
entrapped air shall be removed by gentle agitation achieved by rapid clock -wise and anti-
clock-wise rotation of the vessel. The vessel shall then be emptied and the test piece be
allowed to drain. The test piece shall then be placed on a dry cloth and gently surface
dried with the cloth. It shall be transferred to a second dry clo th when the first one
removes no further moisture. It shall be spread out not more than one stone deep on the
second cloth and left exposed to atmosphere away from direct sunlight or any other
sources of heat for not less than 10 min until it appears to be completely surface dry. The
sample shall then be weighed (B).
       The water in the larger cylinder shall be drained and the sample shall be carefully
taken out and dried in an oven at 100° to 110° c for not less than 24 hours. It shall then be
cooled in a disiccator to room temperature and weighed (A). The room temperature during
the test shall be recorded.


Volume I –Sec..IV         Specifications For Irrigation Projects Nov. 1991       8A/19




       5. Evaluation and Report of Test Results - The water absorption shall be
calculated from the following formula.




                                                                                            313
TECHNICAL SPECIFICATION


                                    B-A
                  Water absorption=         x 100
                                      A


         Where A = Weight of oven dry test piece in gm, and


                  B = Weight of saturated surface dry test piece in gm.


      The water absorption shall be expressed as percentage by weight of oven dry
sample and shall be the average of three determinations.


       Identification of the sample, date when sample was taken and type of stone shall be
reported.


        The size and shape of t est pieces used in the tests shall be indicated.


        A description of the way in which the test pieces were prepared shall be included.




         •••




                                                                                         314
TECHNICAL SPECIFICATION




Volume I –Sec.V           Specifications For Irrigation Projects Nov. 1991   8A/20



                                                APPENDIX - B


                  TEST FOR COMPRESSIVE STRENGTH OF NATURAL BUILDING STONE


       1. Selection of Samples - The sample shall be selected to represent a true
average of the type of grade of stone under consideration. The sample shall be selected
from the quarried stone or taken from the natural rock, as described below and shall be of
adequate size to permit the preparation of the requisite number of test pieces.
       Stone from Ledges or Quarries - The ledge or quarry face of the stone shall be
inspected to determine any variation in different strata. Differences in colour, texture and
structure shall be observed. Separate samples of stone weighing at least 25 kg each of
the unweathered specimens shall be obtained from all strata that appear to vary in colour,
texture and structure. Pieces that have been damaged by blasting, driving, wedges,
heating, etc. shall not be included in the sample.
      Field Stones and Boulders - A detailed inspection of the stones and boulders over
the area shall be made where the supply is to be obtained. The different kinds of stones
and their conditions at various quarry sites shall be recorded. Separate samples for each
class of stone that would be considered for use in c onstruction as indicated by visual
inspection shall be selected.


       2. Test Pieces and Conditioning - Test pieces shall be made from samples
selected in accordance with above and shall be in the form of cubes or c ylinders. They
shall be cut or drilled from the samples. The diameter or lateral dimension (distance



                                                                                        315
TECHNICAL SPECIFICATION


between opposite vertical faces) of a test piece shall not be less than 50 mm and the ratio
of height to diameter or lateral dimensions shall not be less than 1:1 (as shown later).


      The load bearing surfaces shall be finished to as nearly true, parallel and
perpendicular planes as possible by using rock cutting saws, grinding polishing wheels or
abrasive powder. The dimensions of the faces under loading shall be measured to the
nearest 0.2 mm.


      The load-bearing surface and the direction of the rift shall be carefully marked on
each test piece after finishing.
      Three test pieces shall be used for conducting the test in each of the conditions
mentioned below. In each of these conditions, separate tests shall be made for the
specimen when the load is parallel to the rift and perpendicular to the rift. In all twelve test
pieces shall be used.

      The test pieces shall be immersed in water maintained at 20 o to 30 o C for 72 hours,
before testing and shall be tested in saturated condition.


        The test piecesshall also be tested in a dry condition and shall be dried in an oven
of 105 o ±5 o C for 24 hours and cooled in a desiccator to room temperature (20 o to 30 o C).
       3. Apparatus - A testing machine of sufficient capacity for the tests and capable of
applying load at the specified rate shall be used. The machine shall be equipped with two
steel bearing plates with hardened faces. One of the plates (preferably the one that
normally bears on the upper surface of the test pieces) shall be fitted with a ball seating in
the form of a portion of a sphere, the centre of which coincides with the central point of
the face of plate. The other compression plate shall be plain rigid b earing block. The
bearing faces of both plates shall be preferably larger than the normal size of the test
piece to which load is applied. The bearing surface of the plates when new, shall not
depart from a plane be more than 0.0125 mm at any point. The mo vable portion of
spherically seated compression plate shall be held on spherical seat, but the design shall
be such that it is possible to rotate the bearing face freely and tilt it through small angles
in any direction.




Volume I –Sec..V          Specifications For Irrigation Projects Nov. 1991    8A/21



       4. Procedure - The load shall be applied without shock and increased continuously
at a rate of approximately 140 kg/cm 2 of the area per minute until the resistance of the
test piece to the increasing load breaks down and no greater load is sustained. The
maximum load applied to the test piece shall be recorded and the appearance of the stone
and many unusual features in the type of failure shall be noted.


      5. Evaluation and Report of Test Results - The maximum load in kg supported by
the test piece before failure occurs, divided by the area of the bearing face of the
specimen in square cm shall be taken as the compressive strength of the specimen.




                                                                                            316
TECHNICAL SPECIFICATION


      W hen the ratio of height to diameter (or lateral dimension) differs from unity by 25
percent or more, the result shall be calculated to that standard test piece as follows.


                      Cp
         Cc =     0.778+0.222 (b+h)




         Where Cc = Compressive strength of standard test piece.


                           Cp = Compressive strength of the specimen having a height greater
                                than the diameter or lateral dimension,


                           b = diameter or lateral dimension, and


                           h = height.


       The average of the three results in each condition separately above s hall be taken
for purposes of reporting the compressive strength of the sample.


        The compressive strength shall be expressed in kg/cm 2 .


      Identification of the sample, date, when sample was taken and type of stone shall
be reported.


        Size and shape of test pieces used in the tests shall be indicated.


        A description of the way in which the test pieces were prepared shall be included.




•••




                                                                                               317
TECHNICAL SPECIFICATION




Volume I –Sec..VI         Specifications For Irrigation Projects Nov. 1991              9/1



                                    CHAPTER 9 - BRICK MASONRY
9.1 REFERENCES:


       IS:1077-1986          - Specification for common burnt Clay bricks (third revision).


       IS:1081-1960          - Code of practice for fixing and glazing of metal (Steel and Aluminium)
                               doors, windows and ventilators (reaffirmed 1979).


       IS:1905-1985          - Code of practice for structural safety of buildings, Masonry walls (second
                               revision).


       IS:2212-1962          - Code of practice for brick work (with amendment No. 1).


       IS:3495-(Pt.l         - Methods of tests of burnt clay building bricks (second revision) (with
                               amendment No. 1).


       IS:5454-1978          - Methods for sampling of clay building bricks (first revision).


       IS:10440-1983         - Code of practice for design of RB & RBC floors and roofs.


       SP 20(S&T)-1981       - Explanatory Hand Book on Masonry Code.


       SP 25(S&T)-1984       - Hand Book on causes and prevention of cracks in buildings.
                             - Specifications - 77 of Central Public Works Department.
                             - Standard specification - 77 of National Building Organisation.


9.2 DEFINITIONS:



                                                                                                     318
TECHNICAL SPECIFICATION




      Arch - A form of structure having a curved shape, used to support loads or to resist
pressure (See Fig. of PLATE:1/CH -9).*


      Cavity wall - A wall comprising two leaves, each leaf being built of structural units
and separated by a cavity and tied together with met al ties or bonding units to ensure that
the space between the leaves being either left a continuous cavity or filled with non -load
bearing insulating and water proofing material (See Fig. A of Plate: 1/CH -9).*


        Corbel - Bricks projecting from a wall to support a load (See Fig. D of PLATE: 2/CH-9).*


       Cornice - A horizontal projecting moulding decorating the top of building, window
etc. (See Fig. D of PLATE:2/CH -9).*


       Closer - Any portion of a brick used in constructing a wall, to close up the bond
next to the end brick of a course (See Fig. of PLATE 4 & 5/CH -9).*


      Over sailing course - Brick course projecting from a wall for the sake of
appearance only as distinct from corbels, which are load carrying (See Fig. D of
PLATE:2/CH-9).*


       Pier - A thickened section forming integral part of the wall placed at intervals along
the wall primarily to increase the stiffness of the wall or to carry a vertical concentrated
load. The thickness of a pier is the overall thickness of the wall or when bonded into one
leaf of a cavity wall the thickness obtained by treating this leaf as an independent wall
(See Fig B of PLATE:2/CH-9).*


 Pillar - Pillar means a detached masonry support. This can be rectangular, circular,
elliptical etc. In case of rectangular pillars, the breadth shall not exceed more than three
times the thickness and itself shall not exceed more than three bricks. (See Fig C of
PLATE:2/CH-9 and PLATE:3/CH-9).*
* For Figures please refer to the original Specifications published by E-in-C., W.R. Deptt., Bhopal.
Volume I –Sec..VI            Specifications For Irrigation Projects Nov. 1991                      9/2



        Retaining Wall - A wall built to support earth at a higher level on the one side than on the other.


       Scaffolding - A temporar y erection of timber or steel work used in the construction,
alteration, demolition or repairs of a building to support or to allow of the hoisting or
lowering of workmen, their tools and materials.


       Sill - A brick work forming the lower boundary of a door or window opening (See
Fig. D of PLATE:2/CH-9).*




                                                                                                              319
TECHNICAL SPECIFICATION


       Spandrel - The space between the haunches and the road decking of an arch (See
Fig. of PLATE:1/CH-9).*


      String Course - A horizontal course projecting from a wall (usually introduced at
every floor level or under windows or below parapets) for imparting architectural
appearance to the structure and also keeping off the rain water (See Fig. D of
PLATE:2/CH-9).*


9.3 MATERIALS:


        9.3.1 Bricks :


         9.3.1.1 Bricks shall be hand-moulded or machine-moulded and shall be made from
suitable soil. They shall be free from cracks and flaws and nodules of free lime. Hand
moulded bricks of 9 cm height, shall be moulded with a frog 10 to 20 mm deep on one of
its flat sides; the shape and size of the frog shall conform to eithe r Fig. 1 A or Fig. l B.*


        Each brick shall be marked (in the frog where provided) with the manufacturer’s
identification mark or initials.


     9.3.1.2 Bricks used shall be of the specified class and size. The standard sizes of
common building bricks shall be as follows:-


         Type of Bricks ...      Nominal size      ...           Actual size.


         Modular bricks ...      20x10x10 cm       ...           19x9x9 cm


     9.3.1.3 The common clay bricks shall be classified on the basis of average
compressive strength as given in Table 1.




                                                 TABLE : 1
                                           Classification of Bricks


              S.No.       Type of Bricks                 Class          Average Compressive strength

                                                  designation                         (N/mm2)
                                                                        Not less than       Not more than
   1.   First class table moulded (TM) Chimney             5                    5.0              7.5
        kiln burnt brick/Grog or Ghol bricks.
   2.   Second class T.M. Chimney                          3.5                  3.5              5.0



                                                                                                            320
TECHNICAL SPECIFICATION


        kiln burnt bricks.
   3.   Second class T.M. open bhatta or                       3                  3.0          3.5
        Pajawa burnt bricks.
   4.   Kumhar bricks burnt in Pajawa.                         2                  2.0          3.0


The bricks shall have smooth rectangular faces with sharp corners and shall be uniform in colour.
* For Figure please refer to the original Specifications published by E-in-C, W.R. Deptt.,Bhopal.




Volume I –Sec..VI              Specifications For Irrigation Projects Nov. 1991          9/3



       9.3.1.4 Dimensional Tolerances - The scale of sampling for dimensional tolerance
shall be as under:


                    No. of bricks in the lot             No. of bricks to be selected.
                      2,001 to 10,000                                40
                     10,001 to 34,000                                60
                     35,001 to 50,000                                80


        The dimension of bricks when tested in accordance with para 9.3.1.5 shall be within
the following limits per 20 bricks selected at random from the lot.


         (i)        For Bricks of Class Designation 5 and 3.5

                    Length            372 to 388 cm (388 8 cm)

                    Width & height 176 to 184 cm (1886 cm)


         (ii)       For Bricks of Class Designation 3.
                    Length            368 to 392 cm (380 12 cm)

                    Width & Height 174 to 186 cm (180  6 cm)


         (iii)      For Bricks of Class Designation 2.

                    Length            350 to 410 cm (380  30 cm)

                    Width & Height 165 to 195 cm (180  15 cm)


        9.3.1.5 Testing for Physical Characteristics:




                                                                                                     321
TECHNICAL SPECIFICATION


       9.3.1.5.1 Sampling - For carrying out compressive strength, water absorption and
efforescence tests the samples of the bricks shall be taken at random according to the
size of lot as given in Table 2.


                                                  TABLE : 2
                           Scale of Sampling for Physical Characteristics


       Lot Size             Sample size for compressive                      Permissible No. of
                            strength, Water absorption                       defectives for
                            and efflorescence                                efflorescence.


       2,001 to 1,000       ...            5                  ...                  0

       10,001 to 35,000     ...            10                 ...                  0

       35,001 to 50,000     ...            15                 ...                  1


      9.3.1.5.2 Compressive Strength - The bricks when tested in accordance with the
procedure laid down in IS:3495 (Part l) -1976 and given at Appendix -1 shall have a
minimum average compressive strength for various classes as given in Table 1.


      The compressive strength of any individual brick shall not fall below the minimum
average compressive strength specified for the corresponding class of brick by more than
20 per cent.


        In case if the test results for compressive strength exceed the upper limit of the
class for the purpose, the upper limit of t he class should be taken while averaging the
result.


       9.3.1.5.3 Water Absorption - The bricks when tested in accordance with procedure
laid down in IS:3495 (Part II)-1976 and given at Appendix - II after immersion in cold water
for 24 hours the, average water absorption shall not be more than 20 percent by weight.




Volume I –Sec..VI         Specifications For Irrigation Projects Nov. 1991                        9/4



        9.3.1.5.3 Effloresence - The bricks shall be tested for efflo rescence when
specifically so desired by the Engineer-in-charge. The bricks when tested in accordance
with the procedure laid down in IS:3495 (Part lll) -1976 and given at Appendix lll, the rating
of efflorescence shall not be more than “moderate”.


        9.3.1.6 Brick Bats - Brick bats shall be obtained from well burnt bricks.




                                                                                                        322
TECHNICAL SPECIFICATION


       9.3.2 Mortar - Mortar as specified in the respective items shall be used. For
specifications for mortars, refer Chapter 6 -”Mortars”.
9.4 BRICK WORK - GENERAL :
      9.4.1 Bricks - The bricks shall be classified according to class designation of bricks
used. Only Kumhar bricks shall be used for brick masonry in mud mortar.
      9.4.2 Laying - Bricks used for masonry in cement mortar or composite mortar shall
be thoroughly soaked in clean water for a t least an hour immediately before use. (The
absence of bubbling when the soaked brick is immersed in water is the test for thorough
soaking). The soaked bricks shall be kept on a platform free from dirt, mud or any foreign
element. Bricks required for mas onry in mud mortar/fat lime mortar are not to be soaked.


       Bricks shall be laid in English bond (with frogs upwards normally) as shown in Fig.
of PLATE: 5/CH-9* and PLATE:6/CH-9* unless otherwise specified. Half or cut bricks shall
not be used except for closers which may be required to complete the bond it shall be
ensured that all horizontal and vertical joints are completely filled with mortars without any
void in brick work.


       Brickwork shall be raised truely plumb (or true to required batter where so
specified). All courses shall be in the same vertical line. The thickness of brick courses
shall be uniform (slight difference in dimension of bricks being             adjusted in joint
thickness). The levels of window sills, soffit level of lintels and such other impor tant levels
shall be kept as shown in the drawing or otherwise specified and the course shall be so
adjusted as to get complete number of courses upto these levels.


        In case of one brick thick or half brick thick wall at least one face should be kept smooth and plain
even if the other side is slightly rough (due to variation in size of brick). In case of walls of thickness
greater than that of one brick, both the sides shall be smooth and plain.


       All connected brickwork shall be raised uniformly and no portion of brick work shall
be left more than one metre below the rest of the work. Where this is not possible the work shall
be raked back according to bond (and not left toothed) at an angle not steeper than 45 degrees.


      At least one set of tools comprising of wooden straight edges, mason’s spirit level,
square, half metre rule, line and pins, string and plumb line shall be available for each
group of three (or less number of) masons working on a job for regular checking as the
work progresses.


        All iron fixtures, pipes, outlets of water, holdfasts of doors and windows, etc. which
are required to be built into the wall, shall be embedded in cement mortar or in cement
concrete as specified, in their correct position as the brick work is raised. Metal doors,
windows or ventilaors shall however be fixed into prepared openings. They shall not be
built in as the wall go up as this practice often results in brick work, being brou ght right
upto the frame with no clearance allowed and usually distorts the units and increases the
likelihood of damage being done to the unit during subsequent building work. Iron hold
fasts shall be given a protective coat of bitumen to avoid rust ing. W ood-work faces in
contact with brick work shall be treated with wood preservative to prevent attack from
insects and termites.




                                                                                                        323
TECHNICAL SPECIFICATION


* For Figure please refer to the original Specifications published by E-in-C, W.R. Deptt.,Bhopal.
Volume I –Sec..VI          Specifications For Irrigation Projects Nov. 1991             9/5



        9.4.3 Joints :


        9.4.3.1 Bricks shall be so laid that all joints are full of mortar.


      9.4.3.1.1 In brick work the cross -joints in any course shall not be nearer than a
quarter of a brick length from those in the course below or above it.


        9.4.3.1.2 The thickness of a bed joints shall be such that four courses and three
joints taken consecutively sha ll measure equal to 39cm.


       9.4.3.1.3 The thickness of vertical joints shall not exceed 1.0 cm for brick work of
any class designation.


        9.4.3.2 Finishing of Joints :


      9.4.3.2.1 The face joints of brick work may be finished by “jointing” or by “pointing”
as may be specified in the drawing.


        9.4.3.2.2 In jointing either the face joints of the mortar shall be worked out while
still green to give a finished surface flush with the face of the brickwork, or the joints shall
be squarely raked out to a depth of 1 cm, while the mortar is still green for subsequent
plastering. The faces of the brickwork shall be cleaned with wire brush so as to remove
any splashes of mortar during the co urse of raising the brickwork.


       9.4.3.2.3 In pointing, the joints shall be squarely raked out to a depth of 1.5cm
while the mortar is still green and the raked joints shall be well brushed to remove dust
and loose particles and well wetted, and shall be la ter refilled with mortar to give the
required finished e.g. “flush”, “tucked”, “ruled” etc.


      9.4.4 Precaution to prevent cracks - The precautions to be taken to prevent
cracks in the brickwork are given at Appendix - IV and shall be observed.


      9.4.5 Protection and curing - Green work shall be protected from rain by suitable
covering. For proper setting up of mortar the brickwork shall also be protected from drying
up by keeping it constantly wet for at least seven days, except in the case of brickwork
with mud mortar for which no such curing shall be done.


        9.4.6. Scaffolding :




                                                                                                    324
TECHNICAL SPECIFICATION


      For exposed brickwork double scaffolding having two sets of vertical supports shall
be provided. Only minimum number of holes (such holes shall be formed by omitting a
header brick) shall be left in the brickwork for supporting horizontal scaffolding poles. No
hole shall be permitted in pillars under one metre in width, or near the skew backs of
arches. The holes left in the masonry shall be made good by fixing full bricks into t he
holes before plastering. The scaffolding shall be sound and strong and shall be properly
maintained during construction.


      Note - In case of special type of brick work scaffolding shall be got approved from
Engineer-in-charge in advance.


       Note - Paragraphes 9.5.1 (Arches), 9.5.2. (Half brickwork), 9.5.3 (Honey comb
work), 9.5.4 (Mouldings & Cornices), 9.5.5. (Drip course), 9.5.6. (Joining old & New work),
9.5.7 (Cavity walls), Appendix IV (Precautions to prevent cracks) alongwith PLATES 1 to
15/CH-9 have not been included being relevant exclusively to Building work.




Volume I –Sec..VI         Specifications For Irrigation Projects Nov. 1991            9/6



                                                APPENDIX - l

                                TEST FOR COMPRESSIVE STRENGTH

                             (Para 9.3.1.5.2) [Refer IS : 3495 (Part l)-1976]
          1. No. of Specimen - The numbers of specimen as prescribed in table 2 of para 9.3.1.5.1 shall be
taken at random from a lot to be tested. The dimensions shall be measured correct to 1 mm.
       2. Apparatus - A compression testing machine, the compression plate of which
shall have a ball seating in the form of portion of a sphere the centre of which coincides
with the centre of the plate, shall be used.
       3. Preconditioning - Remove unevenness observed in the bed faces to provide two
smooth and parallel faces by grinding. Immerse in water at room temperature for 24 hours.
Remove the specimen and drain out surplus moisture at room temperature. Fill the frog
(where provided) and all voids in the bed face flush with cement mo rtar (1 cement, 1 clean
coarse sand of grade 3 mm and down). Store under the damp jute bags for 24 hours
followed by immersion in clean water for 3 days. Remove, and wipe out any traces of
moisture.
       4. Procedure - Place the specimen with flat faces horizo ntal, and mortar filled face
facing upwards between two 3 -plywood sheets each of 3 mm thickness and carefully
centred between plates of the testing machine. Apply load axially at a uniform rate of 140
kg/cm 2 per minute till failure occurs and note down th e maximum load at failure. The load
at failure shall be the maximum load at which the specimen fails to produce any further
increase in the indicator reading on the testing machine.
        Note - In place of plywood sheets plaster of Paris may be used to ensure a uniform surface for
application of load.
        5. Report - The report shall be as given below :




                                                                                                     325
TECHNICAL SPECIFICATION




                                                     Maximum load at failure in kg.

               Compressive strength in kg/cm2 = Average area of the bed faces in cm2


        6. The average of results shall be reported.


        N.B. - While averaging the results in case if the test results for compressive strength exceed the
               upper limit of the class for the purpose, the upper limit of the class should be taken while
               averaging the results.
                                                                                                      
                                                 APPENDIX - ll
                                    TEST FOR WATER ABSORPTION
                             (Para 9.3.1.5.3) [Refer IS : 3496 (Part ll) - 1976]
       1. No. of Specimen - The number of specimen as prescribed in table 2 of para
9.3.1.5.1 shall be taken at random from a lot to be tested.
      2. Apparatus - A sensitive balance capable of weighing within 0.1 percent o f the
mass of specimen; and a ventilated oven.
      3. Preconditioning - Dry the specimen in a ventilated oven at a temperature of
105 O to 115 O C till it attains substantially constant mass. Cool the specimen to room
temperture and obtain its weight ( M 1 ). Specimen warm to touch shall not be used for the
purpose.
       4. Procedure - Immerse completely dried specimen in clean water at a temperature
27 O  2 O C for 24 hours. Remove the specimen and wipe out any traces of water with a
damp cloth and weigh the specimen. Co mplete the weighing 3 minutes after the specimen
has been removed from water (M 2 ).

      5.W ater absorption, percent by mass, after 24 hours immersion in cold water is
given by the following formula : M 2 - M 1 x 100

                                                         M1


        6. The average of results shall be reported.
                                                                                    
Volume I –Sec..VI          Specifications For Irrigation Projects Nov. 1991            9/7



                                                APPENDIX - lll
                                              EFFLORESCENCE
                             (Para 9.3.1.5.4) [Refer IS : 3495 (Part lll) - 1976]


       1.No. of Specimen - The number of specimen as prescribed in table 2 of para
9.3.1.5.1 shall be taken at random from a lot to be tested.



                                                                                                      326
TECHNICAL SPECIFICATION




       2. Apparatus - A shallow flat bottom dish containing sufficient distilled water to
completely saturate the specimen. The dish shall be made of glass, porcelain, or glazed
stoneware and of size 180 mm x 180 mm x 40 mm depth for square shaped and 200 mm
dia x 40 mm depth for cylindrical shaped.


        3. Procedures - Place the end of the bricks in the dish, the depth of immersion in
water being 25 mm. Place the whole arrangement in a warm (for example, 20 o to 30 o C)
well ventilated room until all the water in the dish is ab sorbed by the specimen & the
surplus water evaporates. Cover the dish containing the brick with suitable glass c ylinder
so that excessive evaporation from the dish may not occur . When the water has been absorbed
and bricks appear to be dry, place a similar quantity of water in the dish and allow it to evaporate as
before. Examine the bricks for efflorescence after the second evaporation and report the results.


            4. Report         - The liability to efflorescence shall be reported as ‘nil’, ‘slight’,
                                  ‘moderate’, ‘heavy’, or ‘seroius’ in accordance with the
                                following          definitions.


             (a) Nil      -     W hen there is no perceptible deposit of efflorence.


             (b) Slight   -      W hen not more than 10 percent of the exposed area of the
                                brick        is covered with a thin deposit of salts.


            (c) Moderate        -        W hen there is a heavy deposit, than under ‘slight’, and
                                covering upto          50 percent of the exposed area of the
                                brick surface but unaccompained      by powdering or flaking of
                                the surface.


            (d) Heavy     -       W hen there is a heavy deposit of salts covering 50 percent or
                                         more of the exposed area of the brick surface but
                                unaccompained               by powdering or flaking of the
                                surface.


            (e) Serious   -     W hen there is heavy deposit of salt accompanied by powdering
                                 and/or flaking of the exposed surfaces.


                                                                                                 




                                                                                                   327
TECHNICAL SPECIFICATION




Volume II –Sec..I          Specifications For Irrigation Projects Nov. 1991                11/1



                                                 CHPATER - 11
                                        PLASTERING AND POINTING
11.1 REFERENCES :


       IS : 383 - 1970    -   Coarse and fine aggregate from natural sources of concrete (Second
                              revision reaffirmed 1980).


       IS : 1661-1972     -   Code of practice for application of cement and lime plaster finishes (First
                              revision)(Reaffirmed 1987).


       IS : 2394 - 1984   -   Code of practice for application of lime plaster finishes (First revision).


       IS : 2402 -1963    -   Code of pratice for external rendered finishes.


       IS : 2645 - 1975   -   Integral cement water proofing compound (first revision) (with amendment
                              No. 1)( Reaffirmed 1987).


       IS : 2750-1964     -   Steel scaffolding (with amendment numbers 1 to 3).


       IS : 3696 (Pt.l)   -   Safety code for scaffolds and ladders : Part l-Scaffolds.
               - 1987
       IS : 8605 - 1977   -   Construction of masonry in dams.
                          -   Specifications - 1977 of “Central Public Works Department”.
                          -   Standard Specification 77 of “National Building Organisation”.
11.2 TERMINOLOGY


         Blistering - The development of one or more local swellings on the finished plaster surface.


                                                                                                            328
TECHNICAL SPECIFICATION




         Cracking - The development of one or more fissures not assignable to structural cause.


       Crazing - The development of series of hair cracks on the finished plaster surface.
Known as ‘map crazing’, when it forms an haphazard pattern over the wall surface
affected.


       Dubbing Out - The operation of attaching pieces of slate, tile, etc., to a wall with
plaster, and then likewise covering them in order to fill out hollows or to form projections.


      Hacking - The roughening of solid backgrounds, by hand or mechanical methods, to
provide a suitable key.


       Raking - Removing mortar from masonry joints to provide suitable key for the
plastering and pointing.


      Rendering - A mix which is applied while plastic, to building surface and which
hardens after application.


       Spatterdash - A mix of cement and fairly coarse sand, prepared as a thick slurry. It
is thrown on as initial coating to provide a key on dense backgrounds having poor suction,
or to reduce or even-out suction of other types of background.


         Suctions - The property of background which determines its rate of absorption of water.


11.3 MATERIALS :


       11.3.1 Cement - This shall conform to specification as given in para 6.3.1 under Chapter 6
“Mortars”.
         11.3.2 Lime Class B and C :
Volume II –Sec..I         Specifications For Irrigation Projects Nov. 1991            11/2



      11.3.2.1 Lime shall conform to specification as given in para 6.3.2. under Chapter 6
“Mortars”.


      11.3.2.2 Lime putty - This shall be obtained by slaking lime water. This shall
conform to specification as given Chapter 6 “Mortar”.


      11.3.3 Neeru - This shall be obtained by mixing lime putty and sand in equal
proportion and chopped jute @4 kg per cu. m of mortar. The mixture shall be properly
ground to a fine paste between two stones.




                                                                                                   329
TECHNICAL SPECIFICATION




      11.3.4 Sand - This shall conform to specification as given in para 6.3.4 under
Chapter 6 “Mortar”. For white or coloured renderings, only quartz or silica sand shall be
used.


        11.3.5 - Aggregates - All aggregates other than sand conform to IS : 383 -1970. For
rough cast, crushed stone or fine gravel upto 12 mm maximum may be used in the
finishing coat. The grading and maximum size will vary according to the texture required
and the type of stone; an aggregate of the desired grading may be obtained either by
using a mixture of sto ne or gravel with sand or by using crushed stone graded from the
maximum down to dust. The proportion of coarse material (over 4.75 mm IS sieve) to
fines shall be between 1:1 and 1:2 by volume.
     11.3.6 Pebbles - These shall be either small pebbles or crush ed stones of size 6 to
12 mm and well washed.
      11.3.7 Water - This shall conform to specification as given in para      6.3.6 under
Chapter 6 “Mortars”.


       11.3.8 Integral Water Proofing Compound - IS:2645 - 1975 shall be followed.
W ater proofing liquid shall be “AZROK” or other equal of approved make.


      11.3.9 Soil - This shall conform to specification as given in para 6.3.5 under
Chapter 6 “Mortars”.


       11.3.10 Chopped Straw (Bhoosa) - Chopped straw for mixing with mud mortar or
plastering shall be clean, thin fib res not longer than 20 mm.


11.4 Care of Tools and Accessories :


       11.4.1 Tools - All tools shall be cleaned by scraping and washing at the end of
each day’s work or after use with different materials. Metal tools shall be cleaned and
greased after operation. The tools shall be examined and thoroughly cleaned before
plastering is begun. Cleanliness is particularly important with cement plaster, where
contamination with set material may seriously affect the performance as well as     the
effective of the tools.


       11.4.2 Scaffolding (staging) - W ooden ballies, bamboos, planks, trestles and other
scaffolding materials shall be sound and in accordance with local building regulations.
These shall be properly examined before erection and use. Steel scaffoldin g, if used shall
conform IS:2750-1964 and used as in IS:3696 (Part l) - 1987.
11.5 Cement and Cement Lime Plaster :
       11.5.1 Suitability of Cement Lime Mixes - The weaker mixes of cement lime
plaster containing small proportions of cement, shall not be used in conjunction with a
strong finishing coat. W eaker mixes offer certain advantages over the stronger (richer)
mixes when applied to non-rigid backgrounds, such as lathing. For trowel finishes (very
smooth surfaces), mixes of lime and cement shall not, in g eneral, be used for finishing
coats as their shrinkage on dr ying creates a tendenc y for surface crazing.



                                                                                       330
TECHNICAL SPECIFICATION


      11.5.2 Number of Plaster Coats - The number of plaster coats to be adopted shall
be as under:


Volume II –Sec..I           Specifications For Irrigation Projects Nov. 1991               11/3



      (i)       Reasonably plain backgrounds of brick, concrete, building blocks and timber
materials.


                    (a) Thickness of plaster - upto 15 mm.                     ...     Single coat.


                    (b) Thickness of plaster - greater than 15 mm.             ...     Two coats.


         (ii) Ver y rough plaster, such as rough stone masonry.                 ... Three coats.


         (iii) Metal lathing.                                                  ...   Three coats


         (iv) Rennovation works on W ood lathes.                               ...   Three coats.


         11.5.3 Thickness of Plastering :


      11.5.3.1 Finishes coats (and single-coat work where employed) shall be of such
minimum thickness as just to provide a sufficient body of materials to harden satisfactorily
under the site conditions in any particular case.


       11.5.3.2 The total thickness of two-coat work exclusive of keys or dubbing out shall
be generally about, but shall not normally exceed 20 mm and it shall not exceed 15 mm in
the case of in situ concrete soffits. The thickness of two -coat work shall be about, but
shall not normally exceed 25 mm.


     11.5.3.3         The thickness of individual coat shall generally be as recommended in
Appendix-l.


         11.5.4 Recommended Plaster Specifications :


       11.5.4.1 A list of specification for mixes suitable for various situations is give n in
Appendix-l which covers single - coat work is used generally and also two and three -coat
works suitable for special situations. The lime in the mixes specified in Appendix -l and in
11.5.4.2 is assumed to be measured as lime putty, but if it is measure d as dry hydrate
lime, the proportion of lime in any mix shall be slightly higher than is indicated and a
suitable adjustment shall be made as indicated in 11.5.4.1.1
      11.5.4.1.1 The actual weight of hydrated                      lime which a putty contains may be
determined b y using the following formula.



                                                                                                      331
TECHNICAL SPECIFICATION


                    Wh = [G/G-1] [Wp-1000]
   Where,

                    Wh = Weight of dry hydrate in kg/m 3,


                    G   = Specified gravity of hydrate usually 2.25, and


                    Wp = weight of putty in kg/m 3,


       11.5.4.2 The mix for the finishing coat shall depend on the texture and colour
of the surface desired. If the surface is to have a lime -putty finish, then it is advisable to
have rich mix of l part of cement, l part of lime and 3 parts of sand. For any roug h finish a
mix of l part of cement to 3 to 4 parts of sand is recommended.
11.5.5 General Precautions in Plastering:
       11.5.5.1 Cleanlines and Protection of Existing work - Cleanlines is essential in
carrying out plaster work. Adequate protection shall be given to all existing operations, but
also in the approaches thereto by covering up with boards, dust sheets, etc., as
necessary. On completion, all work affected by plaste ring operations shall be left clean.
Special care is necessar y when removing set plaster from glass to avoid damaging its
surface.




Volume II –Sec..I            Specifications For Irrigation Projects Nov. 1991   11/4



       11.5.5.2 Suction Adjustment - The careful adjustment of suction is very necessary
for good plastering, and may be done either by wetting the backing suitably if it is dry, or
by sprinkling with a cement-mix as in the case of a concrete sur face with low suction.
W ithout the aid of suction, plaster would creep and slide down due to its own weight. On
the other hand, high rate of suction withdraws all moisture from the plaster and makes it
weak, porous and friable. Too much water makes it imp ossible to keep the mortar in
position till it sets. A failure in bond due to excessive water leads to further failures as the
pocket formed may hold water and break up the plaster when the water freezes; or if the
water is salt-laden the same results will be produced on evaporation by crystal formation.
The wall shall not be soaked but only damped evenly before applying the plaster. If the
surface becomes dr y in spots, such areas shall be moistened again to restore uniform
suction. A fogspray is recommende d for this work.
       11.5.5.3 Adjustment of Working to the Setting Porperties of Plaster - Cement
plasters and cement-lime plasters contain materials which set when brought into contact
with water, and the fullest use of their strength producing properties is not made unless
the mix is applied before the setting process has started. If retempering of such mixes is
carried out after the set has commenced, an inevitable loss in strength and efficienc y will
result. In the case of cement plasters, the commencement of the set is accompanied by a
noticable stiffening of the mix. In the case of cement plaster heavily gauged with lime,
however, it is not always obvious to the operator when the set has started and it is with
this type of mix that the retention of the fu ll measure of strength afforded by the
cementitious material is particularly important. Such plasters may be overworked both
before and after application with resultant impairment of the set of the gauging plaster.
This not only reduces the strength of the material, but also gives it the shrinkage



                                                                                            332
TECHNICAL SPECIFICATION


characteristics of a pure-lime plaster with its liable accompaniment of the surface crazing.
It is essential, therefore, that mixes shall be used as soon as possible after water has
been added and that following w orking periods recommended shall not be exceeded.
          (a) Cement mortar                         ...          30 minutes.
          (b) Cement lime mortar                    ...          2 hours.
         11.5.5.4 Control of Cracking :
       11.5.5.4.1 In the case of discontinuity backgrounds, the best treat ment would be to
separate the two portions by a neat cut through the plaster at the junction. In the case of
discontinuity from wall to ceiling, a cornice that would permit slight movement without
cracking may advantageously be introduced. If it is not pro posed to provide a cornice, A
straight cut through the plaster or a groove joint at the junction may be provided.


       11.5.5.4.2 In load bearing construction, cracks are also in the top floor partitions
due to roof movement by variation in temperature. Develo pment of such cracks shall be
prevented by isolating the top of portion from the roof slab. To achieve this, plastering
shall not be carried over the junctions of partition wall with roof slab.


       11.5.5.4.3 W hen plaster is applied to provide an unbroken surface over board or
slab background, the plaster coat bridging the joints is subject to higher stresses and any
movement in the background will show by cracks along the joints. To avoid this, the
plaster is reinforced at the joints by fixing jute scrim or suitable wire gauge. This treatment
may still be ineffective if large changes in humidity take place and if thin board
background with high moisture movement are used.
       11.5.5.5 Avoidance of Surface Crazing - Surface crazing is due to excessive
shrinkage caused by drying. The shrinkage causes tensile stress in the plaster which is
maximum at the skin. If the shrinkage is great these failures develop into cracks which
exist through the whole depth of the plaster. Attention to the following points will redu ce
surface crazing to a minimum :




Volume II –Sec..I            Specifications For Irrigation Projects Nov. 1991             11/5



           (a)      Use of well-graded sand and suitable proportion of various ingredients for mortar;


           (b)      Thorough grinding of mortar and thorough mixing of different constituents;


           (c)      Proper addition of solutions and other materials to improve the binding
                    properties of mortar;


           (d)      Observance of adequate time intervals between successive coats so tha t
                    each successive coat undergoes a portion of its shrinkage before the next
                    coat is applied and thus reduces the skin tension in the proceeding coat;


           (e)      Proper workmanship as regards application of different coats; and



                                                                                                         333
TECHNICAL SPECIFICATION




           (f)      Avoidance of quick dr ying in the initial stages.


         11.5.6 Preliminary Programming of Work :


        11.5.6.1 All materials necessary for plastering shall be kept readily available at the
site. In cases where lime putty is to be used, it shall be run sufficiently in advance so as
to mature before use. An adequate supply of water suitable for mixing the plaster and for
curing purposes shall be available.


       11.5.6.2 In building operations, such as construction of brick and block walls, the
encasement of steel columns, and beams with concrete, etc ., requiring plastering shall be
so programmed that they are sufficient matured to recieve the plaster without subsequent
damage to plaster or decoration. Careful programming and avoidance of last minute
alterations in the design or in the sequence of work can avoid serious damage to the
plaster finish. W here such alterations are unavoidable the permanent decoration shall be
postponed.
      11.5.6.3 Plastering operations shall not be started until all necessary fixing, such
as door and window frames, mantlepieces are completed and all pipes and conduits to be
embedded in the wall or plaster are installed.
       11.5.6.4 A preliminar y inspection shall be m ade to ensure that the surface are in a
suitable condition for plastering particularly as regards their planeness and dryness. If
dubbing out is necessary, it should be done in advance, so that an adequate time interval
may be permitted before the applicat ion of the first undercoat. Plastering operations shall
be so scheduled as to allow sufficient interval between undercoats and finishing coats.


         11.5.7 Preparation of Background for application of Plaster :
       11.5.7.1 For the durability of the plaster or re ndering, it is vital to obtain a
satisfactory bond between the background and the first plaster coat and also to ensure
that the bond is maintained subsequently. The requirements of good background in this
respect are explained in 11.5.7.1.1 to 11.5.7.1.7. Necessary preparation of the
background is individually dealt with in 11.5.7.2 to 11.5.7.4.
       11.5.7.1.1 Cleanliness - The loose layer of dust on masonry shall be removed
either by watering or by brushing as required. A freshly cast concrete surface is ofte n
covered by laittance and this shall be removed. A concrete surface may also often be
contaminated by the soap which is formed with calcium hydroxide and the oils in the
moulds. The contaminated layer shall be removed by brush. Special care shall be taken in
repairing for rendering an old plaster coat. Old layers of the plaster coat shall be
completely removed and made good.
      Crumbled and frost-damage parts shall be cut out and patched. Any trace of algee
or mass formation shall be removed. If the backgroun d contains soluble salts, particularly
sulphates, application of the plaster shall be done only after the effloresence of the salts
is complete, and the efflorescence is thoroughly removed from the surface.
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      11.5.7.1.2 Roughness - The roughness of the background may generally improve
the bond of the plaster. A smooth surface may be roughened by wire brushing, if it is not



                                                                                          334
TECHNICAL SPECIFICATION


hard; or by hacking or brush-hammering if it is hard. Alternatively; to obtain a rough
surface, a mortar 1 cement : 1.5 to 3 coarse sand by volume, prepared to a wet
consistenc y may be forcibly dashed on to the surface (spattereddash treatment) by
suitable means on to a hard surface like concrete. After roughening the surface, care shall
be taken to moisten the sur face sufficiently before plastering. In addition to general
roughness in the masonr y, the joints shall also be raked to a depth of above 1 centimetre
for providing key to the plaster. On a soft smooth surface after hacking a thin coat of cement slurry
(1:1 = cement : fine sand) may be applied. In special cases wire netting, etc., may be fixed to improve
further the key to the plaster.
       11.5.7.1.3 Suitable Suction - The adjustment of suction of the background during
the application of the plaster is already d ealt with in 11.5.5.2. The amount of water
introduced in the background during its construction has an important bearing and
adequate dr ying intervals shall be allowed between erection and plastering to bring the
surface suitable for suction adjustment.
       11.5.7.1.4 Evenness - The background shall be even in order to avoid variation in
the thickness of the plaster. Any unevenness must be levelled before the plaster is
applied. Local projections in brick work are serious from the point of view of plastering. F or
three coat plaster work, the local projection shall not exceed 1.2 cm of the general surface
as determined by the peripher y of the surface concerned and local depression shall not
exceed 2.0 cm. For two-coat plaster,a local projection shall not exceed 0 .6 cm and local
depression 1.2 cm.
      11.5.7.1.5 Strength and Elasticity - The strength and elasticity of the plaster shall
be compatible with that of the background.
       11.5.7.1.6 Immobility - The background must be immobile at the time of application
of the plaster or subsequently the movements of the background shall be in step with and
in the same direction as those of the plaster. Differential movements between the
background and plaster due to moisture change, temperature change, structural
settlement, deflection etc., will cause cracking of the plaster. The major part of such
movements shall be allowed to set in before the plaster is applied, as for example, by
giving in the case of moisture movement sufficient drying interval to the background.


       11.5.7.1.7 Precaution against discontinuity in Backgrounds - Cracking of walls
or of plaster is often caused by discontinuity, for instance changing from concrete to
brick work, from clay brickwork to lightweight concrete blockwork or even changing from
one type of brick to another. Differential drying shrinkage is probable the main cause but
difference in thermal movements may also contribute Reinforcement of the plaster by
metal lathing or scrim (fabric) over the junction is not always successful. The treatment
shall be as specified under para 11.5.5.4.1 and 11.5.5.4.3.


        11.5.7.2 Surface Preparation for Brickwork or Hollow Block Masonry - The
masonry shall be allowed to dr yout for sufficient period so that initial drying shrinkage is
fairly complete, and suction adj ustment is possible during plastering (see 11.5.7.1.3 and
11.5.7.1.6).


       11.5.7.2.1 Joints of new brickwork or block masonry, if particularly the bricks or
blocks are smooth shall be raked out as the work proceeds (see 11.5.7.1.2). Projecting
bricks shall be trimmed off where necessary (see 11.5.7.1.4).


      11.5.7.2.2 Old brick work shall be considered on its merits with the object of
securing adequate key. The surface shall be thoroughly brushed down to remove dust and


                                                                                                   335
TECHNICAL SPECIFICATION


loose particles for efflorescence where it has occured. Low spots may, where necessary,
be dubbed out at this stage by means of a mix similar to that intended for the first coat of
plaster but stronger (richer) and coarser.
Volume II –Sec..I         Specifications For Irrigation Projects Nov. 1991   11/7




         11.5.7.3 Surface preparation for in -situ concrete :


      11.5.7.3.1 The surface shall be clean and roughened as in 11.5.7.1.1 and
11.5.7.1.2.


       11.5.7.3.2 Concrete surfaces shall have sufficient roughness to provide proper
adhesion (see 11.5.7.1.2). The surface shall be evenly wetted (not saturated) to provide
correct suction (see 11.5.7.1.3). If a chemical retarder has been applied to the formwork,a
roughened surface may be formed by wire-brushing and all the resulting dust and loose
particles cleaned off and care shall be taken that none of the retarders is left on the
concrete or on other surfaces, as it may interfere with the set of the plaster or with o ther
building operations. W here mechanical key-forming devices have been used in the
concrete, these shall be stripped off if still adhering and the resulting surface cleaned
down. Ridges or fins left on soffits or on the sides of concrete beams by shutter ing
imperfactions shall be removed before cleaning down, to be compatible with the plaster
finish particularly when it is not thicker than one centimetre.


      11.5.7.4 Boards and Slabs - W hen the boards or slabs are fixed in accordance with
relevant Indian Standard for fixing wall coverings and fixing ceiling coverings, ‘Scrimming’
(see 11.5.7.1.7) is all the preparation that is necessary.
         11.5.8 Sequence of Operations :


       11.5.8.1 Scaffolding - For all exposed masonry work, double scaffolding having two
sets of vertical supports shall be provided. The supports shall be sound and strong, tied
together with horizontal pieces over which scaffolding planks shall be fixed. For all other
masonry work in buildings, single scaffolding shall be permitted. In such cases, the inner
end of the horizontal scaffolding pole shall rest in a hole provided only in the header
course for the purpose. Only one header for each pole shall be left out. Such holes for
scaffolding shall, however, not be allowed in pillars/columns less t han one metre in width,
or immediately near the skew backs of arches.
         Note - In case of special type of masonry work, scaffolding shall be got approved
                from Engineer-in-charge in advance.


       11.5.8.2 For external plaster, the plastering operations may be st arted from the top
floor and carried downwards. For internal plaster, the plastering operations may be started
wherever the building frame and cladding work are ready and the temporary supports of
the ceiling resting on the wall or the floor have been remo ved.
       11.5.8.3 The surfaces to be plastered shall first be prepared as described in para
11.5.7.



                                                                                         336
TECHNICAL SPECIFICATION


      11.5.8.4 W hen the preparation has been done, arrangements may be made for a
constant supply of plastering material prepared as described in 11.5.9.
       11.5.8.5 The first undercoat is then applied to cellings and walls. It is an advantage
to plaster the ceilings first to permit removal of scaffolding before plastering the wall. In
the case of high rooms, the same scaffolding may be needed for plastering the top
portions of the walls.
       11.5.8.6 The second coat shall be applied after the undercoat has sufficiently set
but not dried in any case within 5 days (not before 2 days and not later than 5 days of the
application of undercoat). Surface of the first undercoat shal l be adjusted and screeds laid
to serve as guides in bringing the work to an even surface. After a further suitable time
interval the finishing coat may be applied first to the ceilings and then to the walls.


      11.5.8.7 Plastering of cornices, decorative                             fe atures,      etc.   shall     normally be
completed before the finishing coat is applied.
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       11.5.8.8 Some times, ends of scaffolding ballies have to be housed in the wall
which is being treated with plaster. In such cases after the ballies are taken out, the hole
of holes left in the wall shall be filled up with brick and mortar, and the patch plastered up
true, even and smooth in conformity with the rest of the wall, so that no sign of any batch work shows
out.


        11.5.8.9 Rendering or chamfering corners, arises, angles and junctions shall be
carried out with proper templates to the sizes as required and shall be completed with the
finishing coat to prevent any joint marks showing out later.
         11.5.9 Mortar for Plaster :
         This shall conform to specification as described in para 6.6.2 and 6.6.5 of Chapter 6 “Mortars”.
         11.5.10 Application of Plaster :
         11.5.10.1 One Coat Plaster Work :
       11.5.10.1.1 Surface on which plaster is to be applied directly, shall be made clean
as per para 11.5.7.1 and dried. The background as per the type of surface, shall be
suitably roughened by raking, wire brushing, bush hammering or by hacking and by
spatterdash treatment in case of relatively smooth background, as described in para
11.5.7.1.2. After roughening the surface, care shall be taken to moisten the surface
sufficeintly and evenly to control suction. For all other types of surfaces where such
plaster is not to be applied directly the precedure and specification as laid down under
para 11.5.5, 11.5.6, 11.5.7 and 11.5.8 shall be followed.


        11.5.10.1.2 The plaster shall be of specified thickness and carried out to the full
length of wall on the natural breaking points like doors and windows. The mortar used
shall be stiff enough to cling and hold when laid. For ceilings the mix is required to be
stiffer than that used for walls. On soffits, the mortar shall be laid in long even spreads
outwards from the operator overlapping each trowel full and using sufficient pressure to
force it into intimate contact with the background. On wa lls the mortar shall be laid on long
even spreads upwards and across, overlapping each trowel full, using sufficient pressure
to force it into intimate contact with the background.




                                                                                                                       337
TECHNICAL SPECIFICATION


       11.5.10.1.3 The plaster shall be laid in a little more than the required t hickness and
levelled with a wooden float. The plaster shall be travelled hard and tight forcing it into
joints to obtain a good bond and surface rubbed smooth with a plaster’s trowel. For
wooden and metal latching, the mortar shall be applied by laying an d spreading diagonally
across the lath work over lapping each trowel full and using sufficient pressure to force it
through the lath work to enable it to lap on the other side. The material shall be laid as
uniformly as possible. The average thickness shal l not exceed 10 mm. This coat shall be
allowed to stand to get firm before denting.


         11.5.10.1.4 The plaster shall be cured as per para 11.5.10.5.


         11.5.10.2 Two Coat Plaster Work :


        11.5.10.2.1 First Coat - The first coat of the specified thickness shall be applied in
a manner similar to one coat plaster mentioned in 11.5.10.1. Before the first coat hardens
its surface shall be beaten up by the edges of wooden tapers and close dents shall be
made on the surface. This helps the plaster in several ways; the cracks are closed, the
mortar is compacted and driven home into the joints and the dents serve as a key to the subsequent coat.
The subsequent coat shall be applied, after this coat has been allowed to set for 2 to 5 days depending
upon weather conditions. The surface shall not be allowed to dry during this period.


       11.5.10.2.2 Second Coat - The second coat shall be completed to the specified
thickness in exactly the same manner as for the first coat. The finishing coat shall be laid
down with a mason’s tro wel to an average thickness of 5 mm.


Volume II –Sec..I         Specifications For Irrigation Projects Nov. 1991          11/9




         11.5.10.2.3 Curing shall be done as described in 11.5.10.5.


      11.5.10.3 Three Coat Plaster Work - The first two coats shall be applied in a
manner as explained in 11.5.10.1 and 11.5.10.2. Before starting to apply the third coat,
the second coat shall be damped evenly as described in 11.5.5.2. The third coat shall be
completed to the spec ified thickness in the same manner as for second coat and shall be
cured as described in 11.5.10.5.


      11.5.10.4 Trueness of Plastering System - The finished plaster surface shall not
show deviation more than 4 mm when checked with a straight edge of 2 m len gth placed
against the surface.


         11.5.10.5 Curing :


      11.5.10.5.1 To develope maximum strength and density in the plaster, it is
necessary to cure cement and cement lime plaster properly. Each coat shall be kept damp
continuously till the next coat is appli ed or for a maximum period of 7 days. Moistening



                                                                                                   338
TECHNICAL SPECIFICATION


shall commence as soon as the plaster has hardened sufficiently and is not succeptible to
injury. The water shall be applied by using a fine fog spray. Soaking of wall shall be
avoided and only as much water as can be readily absorbed shall be used. Excessive
evaporation on the sunny or wind ward sides of buildings in hot dry weather, may be
prevented by hanging mattings or gunny bags on the outside of the plaster and keeping
them wet.


       11.5.10.5.2 After the completion of the finishing coat, the plaster shall be kept wet
for at least seven days, and shall be protected during that period from extremes of
temperature and weather.


         11.5.10.6 Cement Water Proofing Compound :


       11.5.10.6.1 It may be used for cement mortar for plastering           to render it water
proof. It shall be measured by weight.


       11.5.10.6.2 The materials shall be brought to the site in their original packing. The
containers will be opened and the material mixed with dry cement in the proportion by
weight, recommended by the manufacturers or as specially described in the proportion by
weight, recommended by the manufacturers or as specially described in the description of
the item. Care shall be taken in mixing to see that the water proofing materials gets well
and integrally mixed with the cement and does not run out separately when water is
added.


         11.5.11 Coloured Cement Work :


         11.5.11.1 This work may be classified under two categories as follows : -


         (a) In which the coloured cement used in the work is made by intimately grinding
             mineral pigments with the cement clinker, and


         (b) W here mineral pigments are added to white or ordinary (grey) cement to get
             the required shade.


      The former method has the advantage that the work can be carried out in the
absence of skilled workman. The mineral pigment added shall not in any way interfere with
the physical and chemical properties of cement.
      11.5.11.2 In the case of coloured cement plastering, it is necessary to add integral
waterproofer in the undercoats to minimise the risk of efflorescence. W here a coloured
cement plastering is to be done on an already existing mortar base, it is recommended to
apply a surface water proofer on the base and also mix an integral water -proofer with the
coloured cement plaster for the finishing coat.


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                                                                                           339
TECHNICAL SPECIFICATION




11.6 LIME PLASTER :


        11.6.1 Suitability of Lime Plaster :


       11.6.1.1 Lime plasters are characterized by high workability and are generally
suited for internal surfaces. Lime mixes have a long working time, a slow rate of strength
development and reasonable strength.


      11.6.1.2 Lime plastered finishes are not suitable for ex ternal surface in areas of
heavy rainfall, ver y damp places and in places where extreme water tightness is required.


       11.6.1.3 Plastering mixes, based on hydraulic, semi -hydraulic or fat limes may be
successfully used both for under coats and finishing coa ts, provided proper attention is
paid to proportion of various ingredients and workmanship. The plaster hardens by drying
and by recarbonation. This is a slow process and during the early stages after application
the plaster is rather sensitive to shock an d vibration.


       11.6.2 Number of Plaster Coats - Specification given in para 11.5.2 shall be
followed.


      11.6.3 Thickness of Plastering - The thickness for plaster work exclusive of key or
dubbing out shall generally be as given in Table below : -


                                       Thickness for Lime Plaster Work


       S.No.         Type of work                 First coat    Second coat   Third coat
                                                    mm            mm            mm

      (i)            Brick masonry
                     (a) Single coat work            15            ...            ...
                     (b) Double coat work            10            10             ...
      (ii)           Stone masonry                   15            10             ...
      (iii)          Stone masonry (very             15            10             10
                     rough surface).


   11.6.4 Recommended Plaster Specifications :


      11.6.4.1 The recommended mix proportions for lime mortars for plaster work shall
be as given in Appendix - ll. The lime in mortar mixes is assumed to be measured as lime



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TECHNICAL SPECIFICATION


putty. If it is measured as hydrated dry slaked lime, the proportion of lime in any mix shall
be slightly higher than that is indicated and a suitable adjustment shall be made as
indicated in para 11.5.4.1.1.


         11.6.5 General Precautions in Plastering :
       11.6.5.1 Cleanlines and Protection of Existing Work - The specification as given
in para 11.5.5.1 shall be followed.
       11.6.5.2 Suction Adjustment - The specification as given in para 11.5.5.2 shall be
followed.
       11.6.5.3 Adjustment of Working to the Setting Properties of Plaster - Plastering
work shall be completed before the setting process for the mo rtar has started. All mortars
shall be used as soon as possible after grinding, preferably on the same day. If eminently
hydraulic lime (Class A) is present as an ingredient the mortar shall be used within 4
hours after grinding. Lime pozzolana mortar shal l be used within 24 hours of grinding.


       11.6.5.4 Control of Cracking - The specification as given in para 11.5.5.4 shall be
followed.
Volume II –Sec..I             Specifications For Irrigation Projects Nov. 1991                        11/11



      11.6.5.5 Avoidance of Surface Crazing - The specification as given in para
11.5.5.5 shall be followed.


       11.6.6 Preliminary Programming of Work - The specification as given in para
11.5.6 shall be followed.


      11.6.7 Preparation of Backgroun d for Application - The specification as given in
para 11.5.7 shall be followed.


       11.6.8 Sequence of Operations                     - The specification as given in para 11.5.8 shall
be followed.


         11.6.9 Mortar for Plaster - This shall conform to specification as described under Chapter 6"Mortars”.


         11.6.10 Application of Lime Plaster :


         11.6.10.1 To ensure even thickness and a true surface, plaster about 150 mm x 150
mm shall be first applied, horizontally and vertically, at nor more than 2.0 m intervals over
the entire surface to serve as gauges. The surface of these gauged areas shall be applied
in a uniform surfaces slightly more than the specified thickness. This shall be beaten with
thapies to ensure thorough filling of the joints and then brought to a true surface by
working a wooden straight edge reaching across the gauges with small upward and
sideways movements at a time. Finally the surface shall be finished off true with a trowel or wooden
float to a smooth or a sandy granular texture. Excessive trowelling or over working the float shall be




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TECHNICAL SPECIFICATION


avoided. During this process a solution of lime putty shall be applied on the surface to make the latter
workable.
       11.6.10.1.1 In suspending work at the end of the day, the plaster shall be left cut
clean to line both horizontally and vertically, when recommencing the plastering the edge
of the old work shall be scrapped clean and wetted with lime putty before plaster is
applied to the adjacent areas to enable the two to properly join together. Plastering work
shall be closed at the end of the day on the body of wall and not nearer than 150 mm to
any corner or arises. It shall not be closed on the body of feature such as plaster bands
and cornices not at the corners or arises. There shall be no horizontal joints in plaster
work on parapet tops and copings, as these invariably lead to leakages. No portion of the
surface shall be left out initially to be patched up later on.


         11.6.10.2 One Coat Plaster Work :


       11.6.10.2.1 The specification as given in para 11.5.10.1.1 to 11.5.10.1.3 shall be
followed.


      11.6.10.2.2 Trueness of Plastering Systems - Specification as