Concrete Technology and Design 1000+ MCQ with answer for DRDO

1. The minimum diameter of longitudinal bars in a column is
A. 6 mm
B. 8 mm
C. 12 mm
D. 16 mm
Answer : C

2. Which of the following R.C. retaining walls is suitable for heights beyond 6 m?
A. L-shaped wall
B. T-shaped wall
C. Counterfort type
D. All of the above
Answer : C

3. The design yield stress of steel according to IS: 4561978 is: (Where f_y is the characteristic yield strength of steel)
A. 0.37 f_y
B. 0.57 f_y
C. 0.67 f_y
D. 0.87 f_y
Answer : D

4. 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

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

6. '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

7. 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

8. 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

9. The diameter of the Vicat plunger is 10 mm and its length varies from
A. 20 mm to 30 mm
B. 30 mm to 40 mm
C. 40 mm to 50 mm
D. 50 mm to 60 mm
Answer : C

10. The bulk density of aggregates, is generally expressed as
A. Tonnes/cubic metre
B. kg/cubic metre
C. kg/litre
D. g/cm3
Answer : C

11. Pick up the correct statement from the following:
A. A highly absorptive aggregate reduces the workability of concrete considerably
B. The specific gravity of aggregate is important for the determination of the moisture content
C. The absorption and porosity of an aggregate influence the property of the concrete
D. All the above
Answer : D

12. M10 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 : A

13. The property of the ingredients to separate from each other while placing the concrete is called
A. Segregation
B. Compaction
C. Shrinkage
D. Bulking
Answer : A

14. Proper proportioning of concrete, ensures
A. Desired strength and workability
B. Desired durability
C. Water tightness of the structure
D. All the above
Answer : D

15. Pick up the correct statement from the following:
A. According to the petrological characteristics, concrete aggregates are classified as heavy weight, normal weight and light weight
B. According to the shape of the particles, concrete aggregates are classified as rounded irregular, angular and flaky
C. According to the surface texture of the particles, the concrete aggregates are classified as glassy, smooth, granular, rough, crystalline, honey combed and porous
D. All the above
Answer : D

16. A T-shaped retaining wall mainly consists of
A. One cantilever
B. Two cantilevers
C. Three cantilevers
D. Four cantilevers
Answer : C

17. 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

18. 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

19. 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

20. The lower water cement ratio in concrete, introduces
A. Smaller creep and shrinkage
B. Greater density and smaller permeability
C. Improved frost resistance
D. All the above
Answer : D

21. 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

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

23. The compaction of concrete, improves
A. Density
B. Strength
C. Durability
D. All the above
Answer : D

24. For a slab supported on its four edges with corners held down and loaded uniformly, the Marcus correction factor to the moments obtained by Grashoff Rankine's theory
A. Is always less than 1
B. Is always greater than 1
C. Can be more than 1
D. Can be less than 1
Answer : A

25. The internal dimensions of a ware house are 15 m × 5.6 m, and the maximum height of piles is 2.70 m, the maximum number of bags to be stored in two piles, are
A. 1500 bags
B. 2000 bags
C. 2500 bags
D. 3000 bags
Answer : D

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

27. The ratio of various ingredients (cement, sand, aggregates) in concrete of grade M 200, is
A. 1 : 2 : 4
B. 1 : 3 : 6
C. 1 : 1 ½ : 3
D. 1 : 1 : 2
Answer : C

28. 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

29. 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

30. 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

31. Addition of pozzolana to ordinary port land cement, causes
A. Decrease in early strength
B. Reduction in chemical action with sulphates
C. Increase in shrinkage
D. All the above
Answer : D

32. 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

33. 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

34. 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

35. Pick up the incorrect statement from the following:
A. In properly graded aggregates, bulk density is more
B. In single size aggregates, bulk density is least
C. In single size aggregates, bulk density is maximum
D. None of these
Answer : C

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

37. 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

38. Segregation is responsible for
A. Honey-combed concrete
B. Porous layers in concrete
C. Surface scaling in concrete
D. All the above
Answer : D

39. For the construction of the retaining structures, the type of concrete mix to be used, is
A. 1 : 3 : 6
B. 1 : 2 : 4
C. 1 : 1 ½ : 3
D. 1 : 4 : 8
Answer : C

40. The factor which affects workability, is
A. Water content and its temperature
B. Shape and size of the aggregates
C. Air entraining agents
D. All the above
Answer : D

41. 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

42. The commercial name of white and coloured cement in India, is
A. Colorcrete
B. Silvicrete
C. Snowcem
D. All the above
Answer : D

43. The 28 days cube strength of mass concrete using aggregates of maximum size 5 cm for gravity dams should be
A. Between 150 to 300 kg/cm²
B. Between 350 to 600 kg/cm²
C. Between 150 to 500 kg/cm²
D. Below 200 kg/cm²
Answer : D

44. In a spherical dome the hoop stress due to a concentrated load at crown is
A. Compressive everywhere
B. Tensile everywhere
C. Partly compressive and partly tensile
D. Zero
Answer : B

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

46. 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

47. Pick up the correct statement from the following:
A. The maximum size of a coarse aggregate, is 75 mm and minimum 4.75 mm
B. The maximum size of the fine aggregate, is 4.75 mm and minimum 0.075 mm
C. The material having particles of size varying from 0.06 mm to 0.002 mm, is known as silt
D. All the above
Answer : D

48. The maximum amount of dust which may be permitted in aggregates is
A. 5% of the total aggregates for low workability with a coarse grading
B. 10% of the total aggregates for low workability with a fine grading
C. 20% of the total aggregates for a mix having high workability with fine grading
D. All the above
Answer : D

49. 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

50. 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