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

1. In the design of a front counterfort in a counterfort retaining wall, the main reinforcement is provided on (i) Bottom face near counterfort (ii) Top face near counterfort (iii) Bottom face near centre of span (iv) Top face near centre of span The correct answer is
A. Only (i)
B. Only (ii)
C. Both (i) and (iv)
D. Both (ii) and (iii)
Answer : C

2. For compacting plain concrete road surface of thickness less than 20 cm, we use
A. Internal vibrator
B. Screed vibrator
C. Form vibrator
D. None of these
Answer : B

3. 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

4. Pick up the incorrect statement from the following:
A. Space between the exterior walls of a warehouse and bag piles should be 30 cm
B. Cement bags should preferably be piled on wooden planks
C. Width and height of the pile should not exceed 3 m and 2.70 m respectively
D. None of these
Answer : D

5. Workability of concrete mix with low water cement ratio is determined by
A. Tensile strength test
B. Slump test
C. Compaction factor test
D. Flexural strength test
Answer : C

6. 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

7. 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

8. Curing a concrete for long period ensures better
A. Volume stability
B. Strength
C. Water resistance
D. All the above
Answer : D

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

10. The process of proper and accurate measurement of concrete ingredients for uniformity of proportion, is known
A. Grading
B. Curing
C. Mixing
D. Batching
Answer : D

11. The following proportion of the ingredients of concrete mix, is not in conformation to arbitrary method of proportioning
A. 1 : 1 : 2
B. 1 : 2 : 4
C. 1 : 3 : 6
D. 1 : 4 : 10
Answer : D

12. The main reinforcement in the toe of a T-shaped R C. retaining wall is provided on
(i) Top face parallel to the wall
(ii) Top face perpendicular to the wall
(iii) Bottom face parallel to the wall
(iv) Bottom face perpendicular to the wall The correct answer is
A. Only (ii) is correct
B. (i) and (ii) are correct
C. (iii) and (iv) are correct
D. Only (iv) is correct
Answer : D

13. 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

14. For road pavements, the cement generally used, is
A. Ordinary Portland cement
B. Rapid hardening cement
C. Low heat cement
D. Blast furnace slag cement
Answer : B

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. For preparing ordinary concrete, the quantity of water used, is
A. 5% by weight of aggregates plus 20% of weight of cement
B. 10% by weight of aggregates plus 10% of weight of cement
C. 5% by weight of aggregates plus 30% of weight of cement
D. 30% by weight of aggregates plus 10% of weight of cement
Answer : C

23. To obtain cement dry powder, lime stones and shales or their slurry, is burnt in a rotary kiln at a temperature between
A. 1100° and 1200°C
B. 1200° and 1300°C
C. 1300° and 1400°C
D. 1400° and 1500°C
Answer : D

24. If the foundations of all the columns of a structure are designed on the total live and dead load basis, then
A. There will be no settlement of columns
B. There will be no differential settlement
C. The settlement of exterior columns will be more than interior columns
D. The settlement of interior columns will be more than exterior columns
Answer : C

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

26. Batching error means inaccuracy in the quantity of
A. Aggregates
B. Cement
C. Water
D. All the above
Answer : D

27. 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

28. 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

29. 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

30. The maximum percentage of chemical ingredient of cement is that of
A. Magnesium oxide
B. Iron oxide
C. Silica
D. Lime
Answer : D

31. 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

32. Water cement ratio is generally expressed in volume of water required per
A. 10 kg
B. 20 kg
C. 30 kg
D. 50 kg
Answer : D

33. 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

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. 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

36. 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

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. According to I.S. : 456, the number of grades of concrete mixes, is
A. 3
B. 4
C. 5
D. 7
Answer : D

39. 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

40. Pick up the correct statement from the following:
A. Cement should be mixed for at least one minute
B. 10% of water is placed in the rotating drum before adding dry material
C. 10% of water is added after placing the other ingredients in the drum
D. All the above
Answer : D

41. Admixtures which cause early setting and hardening of concrete are called
A. Workability admixtures
B. Accelerators
C. Retarders
D. Air entraining agents
Answer : B

42. 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

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

44. Bulking of sand is maximum if moisture content is about
A. 2 %
B. 4 %
C. 6 %
D. 10 %
Answer : B

45. The grade of concrete M 150 means that compressive strength of a 15 cm cube after 28 days, is
A. 100 kg/cm2
B. 150 kg/cm2
C. 200 kg/cm2
D. 250 kg/cm2
Answer : B

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

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

48. Select the incorrect statement
A. Lean mixes bleed more as compared to rich ones.
B. Bleeding can be minimized by adding pozzolana finer aggregate
C. Bleeding can be increased by addition 'of calcium chloride
D. None of the above
Answer : D

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

50. 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