Important Questions About Concrete -2

Posted on by Iyman Faisal
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25. Why steel is preferred as reinforcement in concrete?

    1. Because it is inexpensive and resistant
    2. Because it is easily accessible
    3. Because it adheres well to concrete
    4. Because it has the same coefficient of expansion of the concrete
      (Hint : All are right but u have to choose the best answer)

Because it has the same coefficient of expansion of the concrete

26.  Air-Entrained concrete is used to ……

    1. Freeze thaw resistance
    2. Freeze thaw non resistance
    3. None of these

Freeze thaw resistance

27. What factors influence the compressive strength of concrete?

    1. Resistance is inversely proportional to the water-cement ratio
    2. The resistance is proportional at the cement content
    3. Cracks appears on the surface due to excessive water content
    4. All of the above

All of the above

28.  On relation  to  the  use  of  air-entraining  agents  in         concrete,  which  of  the following statements are true?

    1. Improve the workability
    2. Improving long-term durability
    3. Makes a less dense mixture
    4. All of the above

All of the above

29. Bleeding can be controlled by:

    1. Adding cement
    2. More vibrating concrete
    3. Adding aggregates
    4. Adding fresh concrete

 Adding cement 

30. Increasing concrete strength is affected by:

    1. Increasing water cement ratio in high workability concrete
    2. Vibrating concrete in high water cement ratio
    3. Bad aggregates sieve & gradation
    4. All of the above

All of the above 

31. What is the factor not to be taken consideration in mix design?

    1. Degree of control of concrete
    2. Strength of concrete
    3. Time of first set of cement
    4. Workability

Time of first set of cement

32.  Initial setting time of cement for asbestos cement products should be not less than:

    1. 30 min.
    2. 50 min.
    3. 75 min.
    4. 90 min.

90 min. 

33. Pick up the correct statements regarding low heat cement from the following:

    1. It possesses less compressive strength
    2. Its initial setting time is about 1 hr
    3. Its final setting time is about 10 hrs.
    4. It’s mainly used for mass concrete work
    5. All of the above

All of the above 

34. Name the type of cement rom the following for canal lining :

    1. Sulphate resistance cement
    2. Rapid hardening cement
    3. Quick setting cement
    4. Pozzolans cement

Sulphate resistance cement

35. The weight of 1 m3 of brick earth is about:

    1. 1200 Kg
    2. 1500 Kg
    3. 1800 Kg
    4. 2000 Kg

1800 Kg 

36. The concrete slump recommended for beams & slabs:

    1. 25  – 50 mm
    2. 25  – 75 mm
    3. 30  – 125 mm
    4. 50  – 100 mm
    5. None of the above

30  –  125 mm

37. The concrete slump for foundation is:

    1. 25 → 50 mm
    2. 30 →125 mm
    3. 50 → 100 mm
    4. 75 →125 mm
    5. None of these

 50 → 100 mm 

38. The process of keeping concrete moist for a certain period after its finishing is known as:

    1. Finishing of concrete
    2. Curing of concrete
    3. Placing of concrete
    4. Compaction of concrete
    5. None of these

 Curing of concrete

39. The form work including the props can be removed from beams, only after

    1. 7 days
    2. 14 days
    3. 21 days
    4. 3 days

14 days  

40. The construction joints in buildings are provided after:

    1. 10 m
    2. 15 m
    3. 20 m
    4. 40 m
    5. 60 m
      Should be 40 – 45 m

40 m

41. Pick up the correct statement from the following:

    1. Cracks appear on the plastered surface in the form of hair cracks
    2. In brick work, the efflorescence is removed by applying a solution of Zinc Sulphate and water
    3. Excessive thermal variations in the backing or plaster cause the plaster to fall
    4. All of the above

All of the above 

42. Pick up the correct statement from the following:

    1. Plain cement concrete is equally strong in compression as well as in tension
    2. Slump test is performed to check concrete strength
    3. Curing of concrete is done for proper compaction of cement
    4. Fineness modulus is the index number expressing the relative sizes of both coarse & fine aggregates
    5. Concrete is a mixture of binding material, coarse aggregates and water

Fineness modulus is the index number expressing the relative sizes of both coarse & fine aggregates 

43. For quality control of Portland cement, the test essentially done is:

    1. Setting time
    2. Soundness
    3. Tensile strength
    4. Consistency
    5. All of the above

All of the above 

44. If 1500 g of water is required to have cement paste 1875 g of normal consistency, the percentage of water is: a) 20%

    1. 25%
    2. 30%
    3. 35%
    4. 40%

Ans: Cement = 1875 – 1500 = 375 g
Therefore; 375/1500 = 0.25 =25% 

45. Hydration of cement is due to chemical action of water with:

    1. Tricalcium silicate and dicalcium silicate
    2. Dicalcium silicate and tricalcium aluminate
    3. Tricalcium aluminate and tricalcium alumino ferrite
    4. All of the above

All of the above 

46. Curing

    1. Reduces the shrinkage of concrete
    2. Preserves the properties of concrete
    3. Prevents the loss of water by evaporation
    4. All of the above

All of the above

47. Curing a concrete for long period ensures better

    1. Volume stability
    2. Strength
    3. Water resistance
    4. Water tightness and durability
    5. All of the above

 All of the above

48. Pick up the correct statement from the following:

    1. Insufficient quantity of water makes the concrete mix harsh
    2. Insufficient quantity of water makes the concrete mix unworkable
    3. Excess quantity of water makes the concrete segregated
    4. Excess quantity of water causes bleeding in concrete
    5. All of the above

All of the above


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