1000+ Concrete Technology and Design Multiple Choice Question Answer [Solved]

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

2. The minimum cover in a slab should neither be less than the diameter of bar nor less than
A. 10 mm
B. 15 mm
C. 25 mm
D. 13 mm
Answer : B

3. 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

4. As compared to ordinary Portland cement, use of pozzolana cement
A. Reduces workability
B. Increases bleeding
C. Increases shrinkage
D. Increases strength
Answer : C

5. A beam curved in plan is designed for
A. Bending moment and shear
B. Bending moment and torsion
C. Shear and torsion
D. Bending moment, shear and torsion
Answer : D

6. Sands of zone I are:
A. Course
B. Medium
C. Medium to fine
D. Fine
Answer : A

7. Due to circumferential action of the spiral in a spirally reinforced column
A. Capacity of column is decreased
B. Ductility of column reduces
C. Capacity of column is decreased but ductility of column increases
D. Both the capacity of column and ductility of column increase
Answer : D

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

9. In a counterfort retaining wall, the main reinforcement in the stem at mid span is provided on
A. Front face only
B. Inner face only
C. Both front face and inner face
D. None of the above
Answer : A

10. For the construction of R.C.C. slabs, columns, beams, walls, etc. the grade of concrete mix used, is
A. 1 : 3 : 6
B. 1 : 1 ½ : 3
C. 1 : 2 : 4
D. 1 : 1 : 2
Answer : C

11. Pick up the incorrect statement from the following. While performing preliminary test on concrete
A. Proportions of the material and water should be the same as to be used at the work site
B. Cement should be mixed by hand in order to maintain uniformity
C. Concrete mix should be stored in air-tight containers
D. Concrete ingredients should be kept at a temperature of 37° ± 2°C
Answer : D

12. 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

13. 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

14. Maximum quantity of water needed per 50 kg of cement for M 15 grade of concrete is
A. 28 liters
B. 30 liters
C. 32 liters
D. 34 liters
Answer : C

15. Sand generally contains salt if it is obtained from:
A. Nala beds
B. River beds
C. Sea beds
D. None of these
Answer : C

16. Setting time of cement increases by adding
A. Gypsum
B. Hydrogen peroxide
C. Calcium chloride
D. Sodium oxide
Answer : A

17. 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

18. The specifications of a cement bag for storage, are
A. Weight 50 kg
B. Height 18 cm
C. Plan area 3000 sq. cm
D. All the above
Answer : D

19. 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

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. A higher modular ratio shows
A. Higher compressive strength of concrete
B. Lower compressive strength of concrete
C. Higher tensile strength of steel
D. Lower tensile strength of steel
Answer : B

22. 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

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

24. The effect of adding calcium chloride in concrete is (i) To increase shrinkage (ii) To decrease shrinkage (iii) To increase setting time (iv) To decrease setting time The correct answer is
A. (i) and (iii)
B. (i) and (iv)
C. (ii) and (iii)
D. (ii) and (iv)
Answer : B

25. 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

26. If the storey height is equal to length of RCC wall, the percentage increase in strength is
A. 0
B. 10
C. 20
D. 30
Answer : B

27. 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

28. Pick up the correct statement from the following:
A. Calcium chloride acts as a retarder
B. Calcium chloride acts as an accelerator
C. Gypsum (calcium sulphate) acts as a retarder
D. Both (b) and (c)
Answer : D

29. Modulus of rupture of concrete is a measure of
A. Flexural tensile strength
B. Direct tensile strength
C. Compressive strength
D. Split tensile strength
Answer : A

30. 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

31. For a concrete mix 1:3:6 and water cement ratio 0.6 both by weight, the quantity of water required per bag, is
A. 10 kg
B. 12 kg
C. 14 kg
D. 16 kg
Answer : C

32. Pick up the correct statement from the following:
A. Sand stones may be divided into calcareous, siliceous and ferruginous sand stones
B. Concrete using sand stones, cracks due to excessive shrinkage
C. Broken bricks produce a concrete having good fire resisting qualities
D. All the above
Answer : D

33. For walls, columns and vertical faces of all structural members, the form work is generally removed after
A. 24 to 48 hours
B. 3 days
C. 7 days
D. 14 days
Answer : A

34. 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

35. For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be
A. 0.75 - 0.80
B. 0.80 - 0.85
C. 0.85 - 0.92
D. Above 0.92
Answer : D

36. The cement whose strength is a little lower than the ordinary cement during the first three months but attains afterwards the same strength, is known as
A. Low-heat Portland cement
B. Rapid hardening Portland cement
C. Portland blast slag cement
D. Portland pozzolana cement
Answer : A

37. Curing
A. Reduces the shrinkage of concrete
B. Preserves the properties of concrete
C. Prevents the loss of water by evaporation
D. All of the above
Answer : D

38. Higher workability of concrete is required if the structure is
A. Made with cement concrete
B. Thick and reinforced
C. Thin and heavily reinforced
D. Thick and heavily reinforced
Answer : D

39. The impurity of mixing water which affects the setting time and strength of concrete, is
A. Sodium sulphates
B. Sodium chlorides
C. Sodium carbonates and bicarbonates
D. Calcium bicarbonates
Answer : C

40. The strength and quality of concrete, depend upon:
A. Grading of aggregates
B. Surface area of aggregates
C. Shape of aggregates
D. All the above
Answer : D

41. The preliminary test is repeated if the difference of compressive strength of three test specimens, exceeds
A. 5 kg/cm²
B. 8 kg/cm²
C. 10 kg/cm²
D. 15 kg/cm²
Answer : D

42. Non-uniform compaction may cause the concrete
A. Porous
B. Non-homogeneous
C. Reduced strength
D. All the above
Answer : D

43. In a spherical dome subjected to concentrated load at crown or uniformly distributed load, the meridional force is always
A. Zero
B. Tensile
C. Compressive
D. Tensile or compressive
Answer : C

44. Maximum distance between expansion joints in structures as per IS: 456 1978 is
A. 20 m
B. 30 m
C. 45 m
D. 60 m
Answer : C

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

46. The datum temperature for maturity by Plowman, is
A. 23°C
B. 0°
C. - 5.6°C
D. - 11.7°C
Answer : D

47. Workability improved by adding
A. Fly ash
B. Hydrated lime
C. Calcium chloride
D. All the above
Answer : D

48. 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

49. 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

50. 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