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  CONCRETE ENGINEERING EXAMINATION
     Module/SubCourse: EN5466 Edition: A

   Situation: Unless otherwise stated, use the following
   information in answering questions 1 and 2.

   Initial Mix Proportions

      Cement = 8.4 sacks
      Water = 33 gallons
      Sand = 8.1 cf or 893 lb
      Gravel = 20.8 cf or 1,971 lb

   Tests on the aggregates reveal that the sand has a 5.4
   percent free surface moisture and the gravel an
   absorption of 0.3 percent The fineness modulus of the
   sand is 2.73.

1. Calculate the net amount of water added by the aggregate
   per cubic yard of concrete (in pounds).

       49.9
       37.5
       54.1
       42.3

2. You are going to batch your concrete by volume. Calculate
   how much sand you should measure out for each cubic
   yard of concrete.

       8.1 cf
       9.5 cf
       11.1 cf
       10.3 cf


   Situation: The maximum concrete pressure is 875 psf.
   You are using 1- by 10-inch board sheathing, 2- by 4-
   inch single studs spaced at 12 inches and double 2- by
   4-inch wales spaced at 20 inches. This situation pertains
   to questions 3 through 5.

3. You are going to use wire ties and have determined the tie
   spacing based on the wale size to be 18 inches and the tie
   spacing based on the wire strength to be 14 inches.
   Determine the final tie spacing, in inches.

       20
       18
       12
       14

4. Calculate the uniform load on the wale.

       900 lb/ft
       875 lb/ft
       875 lb/st
       1,458 lb/ft

5. Calculate the uniform load on the studs.

       900 lb/ft
       875 lb/ft
       875 lb/st
       1,458 lb/ft


   Situation: Unless otherwise specified, use the following
   information to answer questions 6 through 11:

      •Required compressive strength, fc = 3,500 psi

      •Fine aggregate:

     •Fineness modulus = 2.80; specific gravity = 2.71;
   bulk unit weight = 106 pcf

      •Coarse aggregate:

      •Maximum size = 3 inches; specific gravity = 2.66;
   bulk unit weight = 90 pcf

      •Type of structure: reinforced-concrete seawall

      •Climate: severe

      •Design slump = 4 inches

6. The partial volume--the summation of the absolute
   volumes of the cement, water, coarse aggregate, and air--
   18.7 cf. Calculate the loose volume for the fine aggregate.

        140.4 cf
        13.2 cf
        15.3 cf
        1,378 cf

7. Using Type V cement, determine your design water and
   cement ratio.

        0.40
        0.58
        0.50
        0.45

8. Determine the pounds of water to be used per cubic yard of
   concrete.

        275
        250
        300
        265

9. Calculate the pounds of coarse aggregate in the seawall
   mix.

        56.1
        1,899
        21.1
        2,237

10. What is the absolute volume of 1,500 pounds of this coarse
    aggregate?

        8.87 cf
        8.59 cf
        7.63 cf
        9.04 cf

11. Calculate the pounds of cement in a concrete mix
    containing 35 gallons of water and a water and cement
    ratio of 0.50.

        1,092
        583.1
        145.8
        70

12. What is the best type of cement to use in mass concrete
    structures such as concrete dams or bridge abutments?

        III
        IV
        V
        I

13. This cement is a very special cement. It has a low heat of
    hydration intended for applications requiring a minimal
    rate and amount of heat hydration. Its strength also
    develops at a slower rate than the other types. This cement
    will reach its design strength in 90 days. What type of
    cement is described?

        IV
        I
        IS-A
        IIA

14. If the project volume was 5,400 cubic feet, calculate how
    many gallons of water you should take to the job site.

        14,784
        14,112
        6,930
        7,260

15. What is the first step in designing wooden forms for a
    concrete wall or column?

        Determine the production rate and rate of placing
        Determine the concrete placing temperature
        Determine the time required to place the concrete
        Determine the materials to b used in the project

16. What is the workability of a concrete sample measured to?

        The field test for moisture
        The slump test
        The cement/water ratio
        The ASTM test C123 and C142

17. So that completed concrete work is consistent throughout,
    you must--

       Carefully prepare rock, clay, gravel, and sand
   subgrades before mixing the concrete
       Carefully control each handling and transportation step
   to maintain concrete uniformity within a batch
       Carefully control the types and sizes of equipment
   used in the batching process
       Carefully control reconnaissance, site preparation, and
   excavation procedures
18. Water has two functions in the concrete mix. What do the
    functions affect?

          Hydration and workability
          Durability and non-air-entrained properties
          Strength of admixtures and plasticity
      Binding characteristics of the aggregates and
   homogeneity

19. What does the basis of form design do?

          Produces forms that hold plastic concrete
          Saves time
       Offsets the maximum pressure developed during
   placing
          Reduces the effort needed for excavation

20. What does the ratio of the density of aggregate to the
    density of water define?

          Air content of concrete mixes
          Bulk unit weight
          Specific gravity
          Absolute volume weight

21. What do hot-weather concreting techniques include?

          The need to employ insulation blankets
          The need to employ accelerators
          The need to employ high early-strength cement
          The need to employ wet burlap to prevent moisture
   loss

22. As a rule, wall forms should not be removed until--

          Inspection procedures have been determined
       Repair procedures have been thoroughly discussed
       The concrete has thoroughly hardened to support itself
       A minimum of five test specimens of the concrete
   have been analyzed

23. What is the strength of concrete determined by?

       The proper proportioning of admixtures
       The amount of entrained air
       The fine and coarse aggregates
       The basic ratio of water to cement

24. What is the rated production rate for the M919 concrete
    mobile?

       10 cy/hr
       16 cy/hr
       Dependent on the maximum size of the aggregate used
       8 cy/hr

25. To design forms, you must know the strength of the
    forming materials and the loads they must support. The
    following information describes one of four forms. These
    are used for added strength or when a construction will be
    duplicated at more than one location. Initially, they are
    more expensive to use but are more economical in the long
    run if reused often enough. What type of forms are being
    described?

       Wooden
       Fiber
       Metal
       Earth

26. What primary guideline is to be followed during
    concreting operations?

       Test all formwork after plastic cement has been poured
       Test cement, aggregates, and water before beginning
   operations
       Follow the job specification during all phases of the
   operation
       Follow quality-control-assurance guidelines only as
   needed

27. The water and cement ratio is determined by the required
    strength, durability, and watertightness requirements of
    the--

       Flexural strength of concrete
       Hardened concrete
       Compressive strength of concrete
       Plastic cement

28. You are going to construct five vehicle parking pads which
    are to be 12 feet wide, 20 feet long, and 8 inches thick.
    Calculate how many sacks of cement you should order for
    this project.

       55
       274
       273.8
       54.8

29. The maximum concrete pressure is 420 psf and you are
    using 1-inch plywood and 2- by 4-inch single studs.
    Determine the maximum stud spacing, in inches.

       18
       19
       16
       28

30. What do concrete components refer to?

       Hydration, compressive strength, and flexural strength
        Strength, durability, and watertightness
        Workability, homogeneity, and uniformity
        Cement, water, aggregates, and air

31. What is fine aggregate used for in a concrete mixture?

        To protect concrete exposed to freezing and thawing
        To increase compressive and flexural strength
       To decrease the amount of paste (water and cement)
   required for a given concrete quality
       To fill spaces between coarse-aggregate particles and
   increase the workability of the mix

32. What is the first step in any construction procedure?

       Make a thorough and efficient reconnaissance of the
   construction site
        Build approach roads to deliver materials to the site
        Plan and construct the safety facilities needed on site
        Clear, drain, and excavate the construction site

33. What is the chemical reaction between portland cement
    and water which causes concrete to harden to a stonelike
    condition called?

        Hydraulic
        Hydration
        Hydrolysis
        Bleeding

34. You are using three 16S mixers, each producing 16 cubic
    feet of concrete every 4 minutes. Calculate the mixer
    output you should use to design your wall formwork.

        960 cf/hr
        12 cy/hr
        720 cf/hr
        240 cf/hr

35. What desirable properties do plastic concrete include?

        Strength, durability, and watertightness
        Plasticity, slump, and nonsegregation
        Workability, homogeneity, and uniformity
        Uniformity, workability, and durability

36. In materials estimation, when does the determination of the
    total amount of cement come?

        Before the determination of an extra amount of waste
       Before the determination of the required amount of
   water needed for the job
       Before the determination of the total volume of
   concrete to be poured
       After the determination of the required amount of
   water needed for the job

37. By definition, the absolute volume of a material is
    essentially the--

        Sphere occupied by all particles of the material
        Area occupied by the solid particles
       Volume occupied by all particles of the material,
   including voids
        Volume occupied by the solid particles

38. Given a compressive strength of 4,000 psi, using a non-air-
    entrained concrete based on strength, what is the w/c ratio
    by weight?

        0.44
        0.51
        0.40
        0.38
39. What are all aggregates and inert filler materials screened
    to?

        Ensure proper volume
        Ensure proper size gradation
        Ensure that they are all the same size
        Ensure proper weight

40. What is used in the trial-batch method of a mix design?

        Actual job materials to obtain mix proportions
        The M919 concrete mobile to obtain mix proportions
        The absolute volume method to obtain mix proportions
       Laboratory prepared job materials to obtain mix
   proportions

41. What does chemical stability of aggregates influence?

        Strength and durability of all types of structures
        Construction procedures for warehouse floors
        Design of form work
        Water and cement ratio

42. You are going to place concrete into the formwork for a
    wall which is to be 120 feet long, 20 inches wide, and 8
    feet high using a concrete mobile which can produce 1
    cubic yard of concrete every 8 minutes. Calculate the rate
    of placement for which you should design your forms.

        1 foot per hour
        1.5 feet per hour
        8 feet per hour
        5 feet per hour

43. What do admixtures usually cause?
       A physical change within plastic and hardened
   concrete
       A mild reaction in concrete during cold-weather
   operations
       A radical change in the mixing water requirements of
   concrete
        A chemical reaction within the concrete

44. What is the maximum concrete pressure on wall forms
    developed by concrete having a temperature of 80°F and a
    rate of placing of 5 feet per hour?

        700 lbs/sf
        71 lbs/sf
        700 lbs/cf
        71 lbs/cf

45. The finishing process provides the desired final concrete
    surface. What is an example of a finishing process?

        Troweling
        Curing
        Vibration
        Application of wet coverings

46. What is the absolute volume of 700 pounds of cement?

        3.56 cf
        11.22 cf
        7.45 cf
        4.30 cf

47. What is the maximum height a stud can extend upwards
    before walers must be used?

        4 to 5 feet
        5 to 6 feet
       2 to 3 feet
       3 to 4 feet

48. What do the concrete temperature, mixing action, and
    vibration affect?

       Transportation of concrete mixes
       Air content of concrete mixture
       Finishing of hardened concrete
       Homogeneity of hardened concrete

				
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