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Minimum Sample and Test Requirements

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					                                                                                   SD 419


              Density of Low Slump PCC Bridge Deck Overlays In-Place,
                               Nuclear Gauge Method




1.   Scope:

     This test is for determining the in-place density of plastic portland cement concrete
     by nuclear methods.

     Definitions:

     Unit Weight Determination: Field determination of unit weight using the calibrated
     bucket of an air meter and adjusting the results to an air content of 6% (or otherwise
     specified air content).

     Standard Density: Average of the 3 most recent unit weight determinations.

     Lot: A quantity of material from the same source, using the same mix, placed the
     same day, representing a specific segment of construction.

     Density Measurement: A specific individual measurement of in-place density (one of
     3 measurements made for a lot).

     Percent of Standard Density: Relationship of the Density Measurement to the
     Standard Density.




2.   Apparatus:

     2.1    A nuclear density/moisture gauge capable of determining density by the direct
            transmission method.

     2.2    A manufacturer’s instruction manual for the nuclear gauge.

     2.3    Calibration curves or tables required for the gauge.

     2.4    A reference standard for the purpose of taking standard counts and checking
            equipment operation.

     2.5    A supply of rags, a can of WD-40 for cleaning the base and a can of spray
            lubricant containing Teflon to keep the gauge base and probe lubricated.

            When the gauge base is cleaned with WD-40, all residue must be completely
            wiped from the base before applying the spray lubricant.
                                                                             mso.mat 9-10
SD 419
Page 2

           Note: Silicone spray will not be used.

     2.6   Miscellaneous. A measuring tape, chalk or other marking materials (for
           referencing pre-selected sites), test forms, etc.

     2.7   An apparatus for determining the percent of air, SD 403.

     2.8   An apparatus for determining the unit weight, SD 411.

                   NOTE: Cover plate shall be used for strike off on all unit weight
                   determinations for low slump density concrete.




3.   Procedure:

     3.1   Calibration of the Nuclear Gauge:

           A.     The nuclear gauge shall be calibrated as shown in SD 311, paragraph
                  3.1.

     3.2   Selecting Density Measurement Locations.

           A.     Record the location of the lot to be tested by indicating Sta. to Sta.
                  Record the length, width and quantity represented by the lot in square
                  yards (meters).

           B.     During surface preparation operations, pre-selected sites shall be
                  chipped out as required to provide for a minimum depth of overlay of 3”
                  (75 mm) at the measurement site at least 18” x 18” (450 mm x 450
                  mm) in area. Five such sites should be prepared for each lot to provide
                  standby locations in the event a site cannot be measured for density for
                  some reason or in the event additional density measurements are
                  desired. Ordinarily only three of the sites will be used. The center of
                  each site shall be at least 18” (450 mm) from the edge of the lot.

           C.     The pre-selected sites shall be referenced by measurements in such a
                  manner that they can easily be located for density measurement after
                  placement of the overlay.


     3.3   Standard Density Determination.

           A.     The standard density of the material shall be determined by SD 411,
                  with the following exceptions:
mso.mat 9-10
                                                                                  SD 419
                                                                                  Page 3

                (1)   The bucket of the pressure air meter shall be used as the
                      measure. Immediately after the unit weight determination has
                      been completed, the top shall be placed on the air meter and the
                      percentage of entrained air determined (SD 403). The unit
                      weight shall then be adjusted for an air content of 6.0%. This
                      adjustment is determined by multiplying the unit weight times 94
                      and dividing that result by 100.0% minus the percent of
                      entrained air in the concrete.

                (2)   The moving average concept shall be employed. Two unit
                      weight determinations shall be made on the first pour and then
                      one per pour thereafter. The standard density shall be based on
                      the first two determinations, then on the average of the first 3.
                      After the first 3 tests the average of the 3 most recent unit weight
                      determinations shall be used as the standard density. The
                      moving average may include more than one project when the
                      same source, mix and mixing equipment are being used.

                (3)   The validity of the sample is questionable when the unit weight
                      determination varies by more than 1.5 lbs/ft3 (24 kg/m3 ) from
                      the previous standard density.        Another sample shall be
                      obtained immediately and a unit weight determination made to
                      verify or replace the sample in question.


     3.4   Density Measurements.

           A.   After the concrete has been placed and struck off, prior to final
                texturing and tining, locate the pre-selected site, seat the gauge on the
                plastic concrete, extend the probe to the 2” (50 mm) direct transmission
                position and take a 1 minute density reading. Record the density
                count. Pick up the gauge with the probe still extended and remove to
                an area away from the work. Lay the gauge on its side (with the probe
                pointing away from the operator), do not directly touch the probe, but
                using a rag, quickly clean the probe and then retract it to the shielded
                position. Proceed to thoroughly clean all concrete from the bottom of
                the gauge. After cleaning, lightly coat with the lubricant spray and wipe
                dry.

                NOTE: A 2" snap-on probe protection plate is available from
                Region Materials.

           B.   Repeat the procedure for the other 2 selected sites.


4.   Report:

                                                                           mso.mat 9-10
SD 419
Page 4
     4.1   Calculations.

           A.    Standard Density Determinations.

                 (1)       The unit weight shall be calculated by the following formula:

                           Corrected Unit Wt. =      Unit Wt. x 94.0
                                              100 - Determined Air Content

                 Example:

                           Obtained Unit Wt. = 142.4 lbs/ft3 (2281 kg/m3 )
                           Determined Air Content = 7.4%

                           Corrected Unit Wt. =      142.4 (2281) x 94.0
                                                        100 - 7.4

                                              =     142.4 (2281) x 94.0
                                                          92.6

                                              =    144.6 lbs/ft3 (2315 kg/m3 )

           B.    Density Measurements.

                 (1)       Determine the wet density in lbs/ft3 (kg/m3 ) with the gauge.

                 (2)       If a minus correction factor is required, subtract the factor from
                           the wet density in lbs/ft3 (kg/m3 ).

                           Note: When Limestone aggregate is used in the mix, a
                                 correction factor of minus 3.0 lbs/ft3 (48 kg/m3 ) shall
                                 be applied. No correction factor is required for
                                 quartzite mixes.

                 (3)       The resulting corrected density is the wet density at that site and
                           is the density to be averaged with that of the other two sites to
                           determine the density for the lot. Since the standard density is
                           also a wet density, it is not necessary to determine moisture
                           content or dry density.

                 (4)       Percent of Standard Density for each Density Measurement.

                                         % of Standard =

                           (Wet Density, lbs/ft3 (kg/m3 ) - Correction Factor) x 100
                                        Standard Density


mso.mat 9-10
                                                                                  SD 419
                                                                                  Page 5
                   (5)   Percent of Standard Density for the Lot.

                                       % of Standard =

                                   Sum of % of Standard
                                for 3 Density Measurements
                                              3


     4.2   Report.

           A.      Report the Standard Density to the nearest 0.1 lb/ft 3 (kg/m3 ). (DOT-
                   56)

           B.      Report the percent of Standard Density for each site to the nearest 1%.
                   (DOT-56)

           C.      Report the percent of Standard Density for the lot to the nearest 1%.
                   (DOT-56) Figure 1 & 1A

           D.      Report the test satisfactory when:

                   (1)   The percent of Standard Density obtained for the lot is equal to
                         or greater than that specified for the project.

                   (2)   No more than one of the density measurements is below the
                         specified density.

                   (3)   None of the density measurements are more than 2 percentage
                         points below the specified density.

5.   References:

     SD 311
     SD 403
     SD 411
     DOT-56




                                                                            mso.mat 9-10
     SD 419
     Page 6                                                                                                        DOT-56
                                                                                                                    (09/04)
                                              DENSITY REPORT - PC CONCRETE
                                                     (Bridge Deck Overlay)
                                                File #

PROJECT         IM 185-6(9)111              COUNTY           Armstrong                                     PCN             2186

TEST NO.        1                                   TESTED BY           Marv Clauson           CHECKED BY                  BC

NUCLEAR METER NO. MQ 794                  TEST MODE 2" Direct Trans.                 DAILY STANDARD COUNT                  3175

STRUCTURE NO.            64-165-405                                                            DATE              8-8-96

                                            UNIT WEIGHT DETERMINATION
     Test Number                              1      2    ______    Test Number                        1             2
A.   Wt. of Concrete & Measure               47.0   47.3  ______ G. Slump                             1/2"          3/8"
B.   Wt. of Measure                          10.4   10.4  ______ H. Mix. Temp.                        60°           61°
C.   Wt. of Concrete (A - B)                 36.6   36.9  ______    (0F) (0C)
D.   Factor of Measure                       3.95   3.95  ______ I. Air Temp.                         50°           52°
E.   Unit wt. PCF or kg/m3 (C x D)          144.6  145.8  ______    (0F) (0C)
F.   Adjusted Unit Wt. *                    144.3  145.3  ______ J. % Air                             5.8           5.7
     (E X 94) ÷ (100 - J)
                                                     STANDARD DENSITY
K. Compute standard Density:                             144.3     : Line F. from Test No.                          1
      (Average of 3**)                                   145.3     : Line F. from Test No.                          2
   **(Average may be based                                         : Line F. from Test No.
      on 2 tests for first pour)
L. Total                                              289.6
M. Standard Density (Average)                         144.8
                                           IN PLACE DENSITY MEASUREMENTS

Lot Location: Begin Station                100+00             End Station             102+50              Rt. or Lt. of Centerline

Length          250                feet or meters; Width            12         feet or meters; Quantity          333.3        yd2 or m2

  Site     Distance from      Distance from     Wet Density           Correction      Corrected Wet Density            % of
  No.      Lot Beginning       Outer Edge       PCF or kg/m3       (If Applicable)        PCF or kg/m3               Standard
   1            113'                7'             145.8                N/A                                            101
     2          163'                 8'              145.5               N/A                                              100
     3          193'                 2'              146.0               N/A                                              101
     4
     5


Percent of Standard Density Required                98        Average Obtained        101

* If the adjusted unit weight for the most current test is not within 1.5 Lbs/Cu. Ft. (24 kg/m3) of the previous test, a check test
  must be run.


                                                             Figure 1


     mso.mat 9-10
                                                                                                                               SD 419
                                                                                                                               Page 7
                                                                                                                 DOT-56
                                                                                                                  (09/04)
                                              DENSITY REPORT - PC CONCRETE
                                                     (Bridge Deck Overlay)
                                                File #

PROJECT         F 0014(4)347               COUNTY          Armstrong                                      PCN             8836

TEST NO.        1                                 TESTED BY            Marv Clauson           CHECKED BY                  BC

NUCLEAR METER NO. MQ 711 TEST MODE 2" Direct Trans.                                DAILY STANDARD COUNT                   3175

STRUCTURE NO.            10-309-289                                                          DATE               8-8-95


                                            UNIT WEIGHT DETERMINATION
     Test Number                              1      2             Test Number                       1             2
A.   Wt. of Concrete & Measure             21,319 21,500        G. Slump                          12 mm         10 mm
B.   Wt. of Measure                         4717   4717         H. Mix. Temp.                      15.6°         15.8
C.   Wt. of Concrete (A - B)                                       (0F) (0C)
     Metric: (A - B) ÷ 1000                16.602 16.783        I. Air Temp.                        10.0°        11.0
D.   Factor of Measure                      139.5  139.5           (0F) (0C)
E.   Unit wt. PCF or kg/m3 (C x D)          2316   2341         J. % Air                            5.8            5.7
F.   Adjusted Unit Wt. *                    2311   2334
     (E X 94) ÷ (100 - J)
                                                    STANDARD DENSITY
K. Compute standard Density:                            2311      : Line F. from Test No.                         1
      (Average of 3**)                                  2334      : Line F. from Test No.                         2
   **(Average may be based                                        : Line F. from Test No.
      on 2 tests for first pour)
L. Total                                            4645
M. Standard Density (Average)                       2323
                                         IN PLACE DENSITY MEASUREMENTS

Lot Location: Begin Station               1+614             End Station              1+691              Rt. or Lt. of Centerline

Length          77                 feet or meters; Width           3.66      feet or meters; Quantity           2881.8 yd2 or m2

  Site     Distance from      Distance from     Wet Density         Correction      Corrected Wet Density            % of
  No.      Lot Beginning       Outer Edge       PCF or kg/m3     (If Applicable)        PCF or kg/m3               Standard
   1            34                  2              2336               N/A                                            101
     2           50                2.4              2331               N/A                                               100
     3           59                0.6              2339               N/A                                               101
     4
     5


Percent of Standard Density Required              98                         Average Obtained        101

* If the adjusted unit weight for the most current test is not within 1.5 Lbs/Cu. Ft. (24 kg/m3) of the previous test, a check test
  must be run.

                                                           Figure 1A
                                                                                                                   mso.mat 9-10

				
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