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

1. I.S. Sieve Nos. 10 mm and 4.75 mm are generally used for grading of
A. Coarse aggregates
B. Fine aggregates
C. Neither (a) nor (b)
D. Both (a) and (b)
Answer : D

2. Minimum grade of concrete to be used in reinforced concrete as per IS: 4561978 is
A. M 15
B. M 20
C. M 10
D. M 25
Answer : A

3. The individual variation between test strength of sample should not be more than
A. ± 5 % of average
B. ± 10 % of average
C. ± 15 % of average
D. ± 20 % of average
Answer : C

4. 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

5. 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

6. The top diameter, bottom diameter and the height of a slump mould are:
A. 10 cm, 20 cm, 30 cm
B. 10 cm, 30 cm, 20 cm
C. 20 cm, 10 cm, 30 cm
D. 20 cm, 30 cm, 10 cm
Answer : A

7. The centroid of compressive force, from the extreme compression fiber, in limit state design lies at a distance of (Where x_u is the depth of neutral axis at the limit state of collapse)
A. 0.367 x_u
B. 0.416 x_u
C. 0.446 x_u
D. 0.573 x_u
Answer : B

8. 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

9. If the effective plan area of a warehouse is 54 sq. m, and maximum height of piles permitted is 270 cm, the number of cement bags to be stored, is
A. 2000 bags
B. 2200 bags
C. 2400 bags
D. 2700 bags
Answer : D

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

11. 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

12. 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

13. 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

14. A concrete having a slump of 6.5 cm, is said to be
A. Dry
B. Earth moist
C. Semi-plastic
D. Plastic
Answer : D

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

16. The shuttering of a hall measuring 4 m × 5 m, can be removed after
A. 5 days
B. 7 days
C. 10 days
D. 14 days
Answer : B

17. 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

18. In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively
A. Compressive and tensile
B. Tensile and compressive
C. Both compressive
D. Both tensile
Answer : B

19. 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

20. 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

21. 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

22. For given water content, workability decreases if the concrete aggregates contain an excess of
A. Thin particles
B. Flat particles
C. Elongated particles
D. All the above
Answer : D

23. 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

24. 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

25. Maximum percentage reinforcement in case of slabs is limited to
A. 2
B. 4
C. 6
D. 8
Answer : B

26. Diagonal tension in a beam
A. Is maximum at neutral axis
B. Decreases below the neutral axis and increases above the neutral axis
C. Increases below the neutral axis and decreases above the neutral axis
D. Remains same
Answer : C

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

28. 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

29. 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

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

31. The temperature reinforcement in the vertical slab of a T-shaped R.C. retaining wall is
A. Not needed
B. Provided equally on inner and front faces
C. Provided more on inner face than on front face
D. Provided more on front face than on inner face
Answer : D

32. 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

33. For ensuring quality of concrete, use
A. Single sized aggregates
B. Two sized aggregate
C. Graded aggregates
D. Coarse aggregates
Answer : C

34. 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

35. Particles of 0.002 mm size are that of
A. Clay
B. Sand
C. Gravel
D. None of these
Answer : A

36. The compressive strength of 100 mm cube as compared to 150 mm cube is always
A. Less
B. More
C. Equal
D. None of the above
Answer : B

37. 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

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

39. Ordinary concrete is not used for concrete grade
A. M 100
B. M 150
C. M 250
D. M 400
Answer : D

40. The commonly used material in the manufacture of cement is
A. Sand stone
B. Slate
C. Lime stone
D. Graphite
Answer : C

41. Water required per bag of cement, is
A. 7 kg
B. 14 kg
C. 21 kg
D. 35 kg
Answer : D

42. If P, Y and Z are the weights of cement, fine aggregates and coarse aggregates respectively and W/C is the water cement ratio, the minimum quantity of water to be added to first batch, is obtained by the equation
A. 0.1P + 0.3Y + 0.1Z = W/C × P
B. 0.3P + 0.1Y + 0.01Z = W/C × P
C. 0.4P + 0.2Y + 0.01Z = W/C × P
D. 0.5P + 0.3Y + 0.01Z = W/C × P
Answer : B

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

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

45. Critical section for shear in case of flat slabs is at a distance of
A. Effective depth of slab from periphery of column/drop panel
B. d/2 from periphery of column/capital/ drop panel
C. At the drop panel of slab
D. At the periphery of column
Answer : B

46. 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

47. For the construction of thin R.C.C. structures, the type of cement to be avoided, is
A. Ordinary Portland cement
B. Rapid hardening cement
C. Low heat cement
D. Blast furnace slag cement
Answer : D

48. 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

49. The most commonly used admixture which prolongs the setting and hardening time is
A. Gypsum
B. Calcium chloride
C. Sodium silicate
D. All of the above
Answer : A

50. 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