Concrete Technology and Design MCQ Solved Paper for IBPS RRB

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

2. Specified compressive strength of concrete is obtained from cube tests at the end of
A. 3 days
B. 7 days
C. 21 days
D. 28 days
Answer : D

3. To obtain a very high strength concrete, use very fine grained
A. Granite
B. Magnetite
C. Barite
D. Volcanic scoria
Answer : A

4. Construction joints are provided
A. Where B.M. and S.F. are small
B. Where the member is supported by other member
C. At 18 m apart in huge structures
D. All the above
Answer : D

5. Which of the following losses of pre-stress occurs only in pretensioning and not in post-tensioning?
A. Elastic shortening of concrete
B. Shrinkage of concrete
C. Creep of concrete
D. Loss due to friction
Answer : A

6. 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

7. According to IS: 4561978, minimum slenderness ratio for a short column is
A. Less than 12
B. Less than 18
C. Between 18 and 24
D. More than 24
Answer : A

8. Slump test is done for
A. Clay
B. Sand
C. Lime
D. Concrete
Answer : D

9. 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

10. '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

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

12. Pick up the incorrect statement from the following:
A. Tricalcium silicate (C3S) hydrates rapidly
B. Tricalcium silicate (C3S) generates more heat of hydration
C. Tricalcium silicate (C3S) develops early strength
D. Tricalcium silicate (C3S) has more resistance to sulphate attack
Answer : D

13. The permissible diagonal tensile stress in reinforced brick work is
A. About 0.1 N/mm²
B. Zero
C. 0.3 N/mm² to 0.7 N/mm²
D. About 1.0 N/mm²
Answer : A

14. 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

15. Hardening of cement occurs at
A. Rapid rate during the first few days and afterwards it continues to increase at a decreased rate
B. Slow rate during the first few days and afterwards it continues to increase at a rapid rate
C. Uniform rate throughout its age
D. None of these
Answer : D

16. 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

17. Pick up the incorrect statement from the following:
A. A rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive quantity of water
B. The strength of concrete decreases as the water cement ratio increases
C. Good compaction by mechanical vibrations, increases the strength of concrete
D. None of these
Answer : A

18. Pick up the correct statement from the following:
A. Segregation is necessary for a workable concrete
B. Consistency does not affect the workability of concrete
C. If the concrete mix is dry, the slump is maximum
D. None of these
Answer : D

19. 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

20. Pick up the incorrect statement from the following:
A. Concrete for which preliminary tests are conducted, is called controlled concrete
B. Bulking of sand depends upon the fineness of grains
C. Concrete mix 1 : 6 : 12, is used for mass concrete in piers
D. All the above
Answer : D

21. For given workability the grading requiring the least amount of water is one that gives
A. Greatest surface area for the given cement and aggregates
B. Least surface area for the given cement and aggregates
C. Least weight for the given cement and aggregates
D. Greatest weight for the given cement and aggregates
Answer : A

22. Select the incorrect statement
A. The loss of pre-stress is more in pre-tensioning system than in posttensioning system.
B. Pre-tensioning system has greater certainty about its durability.
C. For heavy loads and large spans in buildings or bridges, posttensioning system is cheaper than pre-tensioning system
D. None of the above
Answer : D

23. To ensure constant moisture content in aggregates
A. Area of each aggregate pile should be large
B. Height of each aggregate pile should not exceed 1.50 m
C. Aggregate pile should be left for 24 hours before aggregates are used
D. All the above
Answer : D

24. While designing an air entrained concrete
A. Water cement ratio is reduced
B. Proportion of aggregates is reduced
C. An allowance for the entrained air is made
D. All the above
Answer : D

25. The strength of concrete after one year as compared to 28 days strength is about
A. 10 to 15% more
B. 15 to 20% more
C. 20 to 25% more
D. 25 to 50% more
Answer : C

26. The ratio of the diameter of reinforcing bars and the slab thickness is
A. 1/4
B. 1/5
C. 1/6
D. 1/8
Answer : D

27. Pre-stress loss due to friction occurs
A. Only in post-tensioned beams
B. Only in pre-tensioned beams
C. In both post-tensioned and pre-tensioned beams
D. None of the above
Answer : A

28. The critical section for finding maximum bending moment for footing under masonry wall is located
A. At the middle of the wall
B. At the edge of the wall
C. Halfway between the middle and edge of the wall
D. At a distance equal to effective depth of footing from the edge of the wall
Answer : C

29. Pozzolanic properties exist in
A. Shales
B. Fly ash
C. Pumicite
D. All the above
Answer : D

30. Normally pre-stressing wires are arranged in the
A. Upper part of the beam
B. Lower part of the beam
C. Center
D. Anywhere
Answer : B

31. If the slump of a concrete mix is 60 mm, its workability is
A. Very low
B. Low
C. Medium
D. High
Answer : C

32. 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

33. 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

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

35. Log Angles machine is used to test the aggregate for
A. Crushing strength
B. Impact value
C. Abrasion resistance
D. Water absorption
Answer : C

36. Concrete gains strength due to
A. Chemical reaction of cement with sand and coarse aggregates
B. Evaporation of water from concrete
C. Hydration of cement
D. All the above
Answer : C

37. The light weight aggregates are obtained from
A. Sedimentary rocks
B. Metamorphic rocks
C. Igneous rocks
D. Volcanic source
Answer : D

38. To minimise the effect of differential settlement, the area of a footing should be designed for
A. Dead load only
B. Dead load + live load
C. Dead load + fraction of live load
D. Live load + fraction of dead load
Answer : C

39. The most useless aggregate is one whose surface texture is
A. Smooth
B. Granular
C. Glassy
D. Honey combed and porous
Answer : C

40. The concrete mix which causes difficulty in obtaining a smooth finish, possess
A. Segregation
B. Internal friction
C. Hardness
D. Bleeding
Answer : C

41. According to the recommendations of IS : 456-1978, the expansion joints
A. Are provided where plane changes abruptly
B. Are provided to ensure minimum resistance
C. Do not carry reinforcement across them
D. All the above
Answer : D

42. 1% of voids in a concrete mix would reduce its strength by about
A. 5 %
B. 10 %
C. 15 %
D. 20 %
Answer : A

43. 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

44. M 150 grade of concrete approximates
A. 1 : 3 : 6 mix
B. 1 : 1 :2 mix
C. 1 : 2 : 4 mix
D. 1 : 1.5 : 3 mix
Answer : B

45. Sand requiring a high water cement ratio, belongs to
A. Zone I
B. Zone II
C. Zone III
D. Zone IV
Answer : A

46. The limits of percentage p of the longitudinal reinforcement in a column is given by
A. 0.15% to 2%
B. 0.8% to 4%
C. 0.8% to 6%
D. 0.8% to 8%
Answer : C

47. The property of fresh concrete, in which the water in the mix tends to rise to the surface while placing and compacting, is called
A. Segregation
B. Bleeding
C. Bulking
D. Creep
Answer : B

48. Which of the following statements is incorrect?
A. Minimum cross sectional area of longitudinal reinforcement in a column is 0.8%
B. Spacing of longitudinal bars measured along the periphery of column should not exceed 300 mm
C. Reinforcing bars in a column should not be less than 12 mm in diameter
D. The number of longitudinal bars provided in a circular column should not be less than four
Answer : D

49. To hydrate 500kg of cement full water needed, is
A. 100 kg
B. 110 kg
C. 120 kg
D. 130 kg
Answer : D

50. 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