1000+ Concrete Technology and Design MCQ for NDA [Solved]

1. The maximum thickness of concrete floor of a cement warehouse, is
A. 10 cm
B. 15 cm
C. 20 cm
D. 25 cm
Answer : D

2. An excess of flaky particles in concrete aggregates
A. Decreases the workability
B. Increases the quantity of water and sand
C. More than 15% are not desirable
D. All the above
Answer : D

3. A continuous beam is deemed to be a deep beam when the ratio of effective span to overall depth (1/D) is less than
A. 1.5
B. 2.0
C. 2.5
D. 3.0
Answer : C

4. Poisson's ratio for concrete
A. Remains constant
B. Increases with richer mixes
C. Decreases with richer mixes
D. None of the above
Answer : B

5. 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

6. To prevent segregation, the maximum height for placing concrete, is
A. 100 cm
B. 125 cm
C. 150 cm
D. 200 cm
Answer : A

7. Pick up the correct statement from the following:
A. Higher workability indicates unexpected increase in the moisture content
B. Higher workability indicates deficiency of sand
C. If the concrete mix is dry, the slump is zero
D. All the above
Answer : D

8. A flaky aggregate is said to be elongated if its length is
A. Equal to the mean size
B. Twice the mean size
C. Thrice the mean size
D. Four times the mean size
Answer : B

9. 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

10. Hydration of cement is due to chemical action of water with
A. Tricalcium silicate and dicalcium silicate
B. Dicalcium silicate and tricalcium aluminate
C. Tricalcium aluminate and tricalcium alumino ferrite
D. All the above
Answer : D

11. The percentage of voids in cement is approximately
A. 25 %
B. 40 %
C. 60 %
D. 80 %
Answer : B

12. 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

13. After casting, an ordinary cement concrete on drying
A. Expands
B. Mix
C. Shrinks
D. None of these
Answer : C

14. Approximate value of shrinkage strain in concrete, is
A. 0.003
B. 0.0003
C. 0.00003
D. 0.03
Answer : B

15. Pick up the incorrect statement from the following:
A. The bottom and top ends of slump mould are parallel to each other
B. The axis of the mould is perpendicular to the end faces
C. The internal surface of the mould is kept clean and free from set cement
D. The mould is in the form of a frustum of hexagonal pyramid
Answer : D

16. 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

17. Which of the following has high tensile strength?
A. Plain hot rolled wires
B. Cold drawn wires
C. Heat treated rolled wires
D. All have same tensile strength
Answer : B

18. The final operation of finishing floors, is known as
A. Screeding
B. Floating
C. Trowelling
D. Finishing
Answer : C

19. For a simply supported beam of span 15 m, the minimum effective depth to satisfy the vertical deflection limits should be
A. 600 mm
B. 750 mm
C. 900 mm
D. More than 1 m
Answer : B

20. For a longitudinal reinforcing bar in a column, the minimum cover shall neither be less than the diameter of bar nor less than
A. 15 mm
B. 25 mm
C. 30 mm
D. 40 mm
Answer : D

21. Grading of sand causes great variation in
A. Workability of concrete
B. Strength of concrete
C. Durability of concrete
D. All the above
Answer : D

22. High temperature
A. Increases the strength of concrete
B. Decreases the strength of concrete
C. Has no effect on the strength of concrete
D. None of these
Answer : B

23. According to IS : 382-1963, a good aggregate should be
A. Chemically inert
B. Sufficiently strong
C. Hard and durable
D. All the above
Answer : D

24. The slab is designed as one way if the ratio of long span to short span is
A. Less than 1
B. Between 1 and 1.5
C. Between 1.5 and 2
D. Greater than 2
Answer : D

25. Minimum pitch of transverse reinforcement in a column is
A. The least lateral dimension of the member
B. Sixteen times the smallest diameter of longitudinal reinforcement bar to be tied
C. Forty-eight times the diameter of transverse reinforcement
D. Lesser of the above three values
Answer : D

26. Minimum thickness of load bearing RCC wall should be
A. 50 mm
B. 100 mm
C. 150 mm
D. 200 mm
Answer : B

27. Saw dust can be rendered chemically inert by boiling it in water containing
A. Ferrous sulphate
B. Potassium chloride
C. Ammonia
D. Nitric acid
Answer : A

28. An ordinary Portland cement when tested for its fineness, should not leave any residue on I.S. sieve No. 9, more than
A. 5 %
B. 10 %
C. 15 %
D. 20 %
Answer : B

29. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is
A. 30 %
B. 40 %
C. 50 %
D. 60 %
Answer : A

30. Select the correct statement
A. Elastic modulus of high tensile steel is nearly the same as that of mild steel
B. Elastic modulus of high tensile steel is more than that of mild steel
C. Carbon percentage in high carbon steel is less than that in mild steel
D. High tensile steel is cheaper than mild steel
Answer : A

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

32. C.R.R.I. charts are used to obtain a relationship between strength of concrete and
A. Water cement ratio
B. Workability
C. Grading of aggregate
D. Fineness modulus
Answer : A

33. Pick up the correct statement from the following:
A. The concrete gains strength due to hydration of cement
B. The concrete does not set at freezing point
C. The strength of concrete increases with its age
D. All the above
Answer : D

34. Di-calcium silicate (C₂S)
A. Hydrates rapidly
B. Generates less heat of hydration
C. Hardens rapidly
D. Provides less ultimate strength to cement
Answer : B

35. Modulus of elasticity of steel as per IS: 4561978 shall be taken as
A. 20 kN/cm²
B. 200 kN/cm²
C. 200 kN/mm²
D. 2 × 106 N/cm²
Answer : C

36. The operation of removing humps and hollows of uniform concrete surface, is known as
A. Floating
B. Screeding
C. Trowelling
D. Finishing
Answer : B

37. 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

38. Pick up the correct statement from the following:
A. Construction joints are necessarily planned for their locations
B. Expansion joints are provided to accommodate thermal expansion
C. Construction joints are provided to control shrinkage cracks
D. All the above
Answer : D

39. Workability of concrete for a given water content is good if the aggregates, are
A. Rounded aggregate
B. Irregular aggregate
C. Angular aggregate
D. Flaky aggregates
Answer : A

40. '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

41. Due to shrinkage stresses, a simply supported beam having reinforcement only at bottom tends to
A. Deflect downward
B. Deflect upward
C. Deflect downward or upward
D. None of the above
Answer : A

42. The purpose of reinforcement in pre-stressed concrete is
A. To provide adequate bond stress
B. To resist tensile stresses
C. To impart initial compressive stress in concrete
D. All of the above
Answer : C

43. 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

44. The minimum cover to the ties or spirals should not be less than
A. 15 mm
B. 20 mm
C. 25 mm
D. 50 mm
Answer : C

45. Separation of water or water sand cement from a freshly concrete, is known
A. Bleeding
B. Creeping
C. Segregation
D. Flooding
Answer : A

46. According to IS: 4561978, the maximum reinforcement in a column is
A. 2 %
B. 4 %
C. 6 %
D. 8 %
Answer : C

47. 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

48. Which of the following statements is incorrect?
A. Higher Vee-Bee time shows lower workability
B. Higher slump shows higher workability
C. Higher compacting factor shows higher workability
D. None of the above
Answer : D

49. Pick up the incorrect statement applicable to the field test of good cement.
A. When one thrusts one's hand into a bag of cement, one should feel warm
B. The colour of the cement is bluish
C. By rubbing cement in between fingers, one should feed rough
D. All the above
Answer : D

50. For the construction of cement concrete dams, the maximum permissible size of the aggregates, is
A. 40 mm
B. 50 mm
C. 60 mm
D. 70 mm
Answer : A