GRE - Concrete Technology and Design 1000+ MCQ [Solved] PDF Download

1. Bulking of sand is
A. Mixing of different sizes of sand particles
B. Mixing of lime with sand
C. Maximum water with sand
D. Swelling of sand when wetted
Answer : D

2. Pick up the correct statement from the following:
A. Continuous grading is not necessary for obtaining a minimum of air voids
B. The omission of a certain size of aggregate is shown by a straight horizontal line on the grading curve
C. The omission of a certain size of aggregate in concrete increases the workability but also increases the liability to segregation
D. All the above
Answer : D

3. While compacting the concrete by a mechanical vibrator, the slump should not exceed
A. 2.5 cm
B. 5.0 cm
C. 7.5 cm
D. 10 cm
Answer : B

4. For batching 1:3:6 concrete mix by volume, the ingredients required per bag of 50 kg cement, are:
A. 70 litres of sand and 120 litres of aggregates
B. 70 kg of sand and 140 litres of aggregates
C. 105 litres of sand and 140 litres of aggregates
D. 105 litres of sand and 210 litres of aggregates
Answer : D

5. The process of hardening the concrete by keeping its surface moist is known
A. Placing
B. Wetting
C. Curing
D. Compacting
Answer : C

6. The aggregate containing moisture in pores and having its surface dry, is known as
A. Moist aggregates
B. Very dry aggregates
C. Dry aggregates
D. Saturated surface dry aggregate
Answer : D

7. Air entrainment in the concrete increases
A. Workability
B. Strength
C. The effects of temperature variations
D. The unit weight
Answer : A

8. Addition of pozzolana to cement
A. Decreases workability
B. Increases strength
C. Increases heat of hydration
D. None of these
Answer : D

9. A construction joint is provided where
A. Bending moment is small
B. Shear force is small
C. The member is supported by other member
D. All the above
Answer : D

10. The recommended value of modular ratio for reinforced brick work is
A. 18
B. 30
C. 40
D. 58
Answer : C

11. The load carrying capacity of a helically reinforced column as compared to that of a tied column is about
A. 5 % less
B. 10 % less
C. 5 % more
D. 10 % more
Answer : C

12. The produce impermeable concrete
A. Thorough mixing of concrete is required
B. Proper compaction of concrete is required
C. Proper curing of concrete is required
D. All the above
Answer : D

13. The main reason for providing number of reinforcing bars at a support in a simply supported beam is to resist in that zone
A. Compressive stress
B. Shear stress
C. Bond stress
D. Tensile stress
Answer : C

14. Permissible compressive strength of M 200 concrete grade is
A. 100 kg/cm2
B. 150 kg/cm2
C. 200 kg/cm2
D. 250 kg/cm2
Answer : C

15. The high strength of rapid hardening cement at early stage, is due to its
A. Finer grinding
B. Burning at high temperature
C. Increased lime cement
D. Higher content of tricalcium
Answer : C

16. For the design of retaining walls, the minimum factor of safety against overturning is taken as
A. 1.5
B. 2.0
C. 2.5
D. 3.0
Answer : B

17. Water cement ratio is
A. Volume of water to that of cement
B. Weight of water to that of cement
C. Weight of concrete to that of water
D. Both (a) and (b) of the above
Answer : D

18. The relation between modulus of rupture f_cr, splitting strength f_cs and direct tensile strength f_cl is given by
A. f_cr - f_cs = f_cl
B. f_cr > f_cs > f_cl
C. f_cr < f_cs < f_cl
D. f_cs > f_cr > f_cl
Answer : B

19. Slump test of concrete is a measure of its
A. Consistency
B. Compressive strength
C. Tensile strength
D. Impact value
Answer : A

20. W_p and W_f are the weights of a cylinder containing partially compacted and fully compacted concrete. If the compaction factor (W_p/W_f) is 0.95, the workability of concrete is
A. Extremely low
B. Very low
C. Low
D. High
Answer : D

21. The effect of creep on modular ratio is
A. To decrease it
B. To increase it
C. Either to decrease or to increase it
D. To keep it unchanged
Answer : B

22. Too wet concrete may cause
A. Weakness of concrete
B. Excessive laitance
C. Segregation
D. All the above
Answer : D

23. The risk of segregation is more for
A. Wetter mix
B. Larger proportion of maximum size aggregate
C. Coarser grading
D. All the above
Answer : D

24. High carbon content in the steel causes
A. Decrease in tensile strength but increase in ductility
B. Increase in tensile strength but decrease in ductility
C. Decrease in both tensile strength and ductility
D. Increase in both tensile strength and ductility
Answer : B

25. Pick up the correct statement from the following:
A. The free water is the amount of water added while mixing and the amount of water held on the surface of the aggregates prior to mixing
B. The total water is the free water and the amount actually absorbed by the aggregates
C. Neither (a) nor (b)
D. Both (a) and (b)
Answer : D

26. If X, Y and Z are the fineness modulli of coarse, fine and combined aggregates, the percentage (P) of fine aggregates to combined aggregates, is
A. P = [(Z - X)/(Z - Y)] × 100
B. P = [(X - Z)/(Z - Y)] × 100
C. P = [(X - Z)/(Z + Y)] × 100
D. P = [(Z + X)/(Z - Y)] × 100
Answer : B

27. If the average compressive strength is 4000 kg/cm2 and standard deviation is 500, the co-efficient of variation is
A. 10 %
B. 12.5 %
C. 15 %
D. 18.5 %
Answer : B

28. The bulk density of aggregates does not depend upon:
A. Size and shape of aggregates
B. Specific gravity of aggregates
C. Grading of aggregates
D. Size and shape of the container
Answer : D

29. The process of mixing, transporting, placing and compacting concrete using Ordinary Port land Cement should not take more than
A. 30 minutes
B. 40 minutes
C. 60 minutes
D. 90 minutes
Answer : A

30. If the various concrete ingredients i.e. cement, sand and aggregates are in the ratio of 1:3:6, the grade of concrete, is
A. M 100
B. M 150
C. M 200
D. M 250
Answer : A

31. In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively
A. Compressive and tensile
B. Tensile and compressive
C. Both compressive
D. Both tensile
Answer : B

32. Inert material of a cement concrete mix, is
A. Water
B. Cement
C. Aggregate
D. None of these
Answer : C

33. In a ring beam subjected to uniformly distributed load (i) Shear force at mid span is zero (ii) Shear force at mid span is maximum (iii) Torsion at mid span is zero (iv) Torsion at mid span is maximum The correct answer is
A. (i) and (iii)
B. (i) and (iv)
C. (ii) and (iii)
D. (ii) and (iv)
Answer : A

34. In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mm diameter for
A. 20 times
B. 25 times
C. 30 times
D. 50 times
Answer : B

35. Pick up the correct statement from the following:
A. High percentage of C₃S and low percentage of C₂S cause rapid hardening
B. High percentage of C₃S and low percentage of C₂S make the cement less resistive to chemical attack
C. Low percentage of C₃S and high percentage of C₂S contribute to slow hardening
D. All the above
Answer : D

36. If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called
A. Balanced beam
B. Under-reinforced beam
C. Over-reinforced beam
D. None of the above
Answer : C

37. 'Ware house pack' of cement means
A. Full capacity of the ware house
B. Pressure exertion of the bags of upper layers
C. Pressure compaction of the bags on lower layers
D. Packing the ware house
Answer : C

38. Pick up the correct statement from the following:
A. The weight of ingredients of concrete mix, is taken in kilograms
B. Water and aggregates are measured in litres
C. 20 bags of cement make one tonne
D. All the above
Answer : D

39. Transport of concrete by pumps, is done for a distance of
A. 100 m
B. 200 m
C. 300 m
D. 400 m
Answer : D

40. Tricalcium aluminate (C₃A)
A. Reacts fast with water
B. Generates less heat of hydration
C. Causes initial setting and early strength of cement
D. Does not contribute to develop ultimate strength
Answer : B

41. The type of aggregates of same nominal size, which contain less voids when compacted, are
A. Rounded spherical
B. Irregular
C. Flaky
D. None of these
Answer : A

42. Workability improved by adding
A. Air-entraining agent
B. Foaming agent
C. Oily-agent
D. All the above
Answer : D

43. The approximate value of the ratio between direct tensile strength and flexural strength is
A. 0.33
B. 0.5
C. 0.75
D. 1.0
Answer : B

44. Stress strain curve of high tensile steel
A. Has a definite yield point
B. Does not show definite yield point but yield point is defined by 0.1% proof stress
C. Does not show definite yield point but yield point is defined by 0.2% proof stress
D. Does not show definite yield point but yield point is defined by 2% proof stress,
Answer : C

45. The depth of footing for an isolated column is governed by (i) Maximum bending moment (ii) Shear force (iii) Punching shear The correct answer is
A. Only (i)
B. (i) and (ii)
C. (i) and (iii)
D. All (i), (ii) and (iii)
Answer : D

46. According to ISI recommendations, the maximum depth of stress block for balanced section of a beam of effective depth d is
A. 0.43 d
B. 0.55 d
C. 0.68 d
D. 0.85 d
Answer : A

47. Pick up the correct statement from the following:
A. Insufficient quantity of water makes the concrete mix harsh
B. Insufficient quantity of water makes the concrete unworkable
C. Excess quantity of water makes the concrete segregated
D. All the above
Answer : D

48. Le-Chatelier's apparatus is used for testing
A. Soundness of cement
B. Hardness of cement
C. Strength of cement
D. Durability of cement
Answer : A

49. Proper batching ensures
A. Economy
B. Durability
C. Workability
D. All the above
Answer : D

50. The type of aggregates not suitable for high strength concrete and for pavements subjected to tension, is
A. Rounded aggregate
B. Irregular aggregate
C. Angular aggregate
D. Flaky aggregate
Answer : A