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

1. 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

2. 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

3. 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

4. In a pile of length l, the points of suspension from ends for lifting it are located at
A. 0.207 l
B. 0.25 l
C. 0.293 l
D. 0.333 l
Answer : A

5. The bulk density of aggregates, depends upon
A. Shape
B. Grading
C. Compaction
D. All the above
Answer : D

6. Pick up the correct statement from the following:
A. Sand obtained from pits, is washed to remove clay and silt
B. Sand obtained from flooded pits, need not be washed before use
C. The chloride in sea shore sand and shingle may cause corrosion of reinforcement if the concrete is porous
D. All the above
Answer : D

7. 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

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

9. If a grading curve is horizontal between the portions of 20 mm I.S. Sieve and 4.75 mm I.S. Sieve, the graded aggregates do not contain
A. 20 mm particles
B. 10 mm particles
C. 4.75 mm particles
D. All the above
Answer : D

10. 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

11. If the permissible stress in steel in tension is 140 N/mm², then the depth of neutral axis for a singly reinforced rectangular balanced section will be
A. 0.35 d
B. 0.40 d
C. 0.45 d
D. Dependent on grade of concrete also
Answer : B

12. 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

13. The process of hardening the concrete by keeping its surface moist is known
A. Placing
B. Wetting
C. Curing
D. Compacting
Answer : C

14. 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

15. If the engineer-in-charge approves, the 10 cm cubes may be used for the work test of concrete provided maximum nominal size of aggregate, does not exceed
A. 10 cm
B. 15 cm
C. 20 cm
D. 25 cm
Answer : C

16. In the method of voids for determination of the quantity of cement paste, it is assumed that
A. Voids in coarse aggregates are filled by fine aggregates
B. Voids in fine aggregates are filled by the cement paste
C. Volume of fine aggregates is equal to total voids in coarse aggregates plus 10% extra
D. All the above
Answer : D

17. 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

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

19. Efflorescence in cement is caused due to an excess of
A. Alumina
B. Iron oxide
C. Silica
D. Alkalis
Answer : D

20. 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

21. 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 o these
Answer : A

22. 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

23. The main reinforcement in the heel of a T-shaped R.C. retaining wall is provided on
A. Top face perpendicular to wall
B. Bottom face perpendicular to wall
C. Both top and bottom faces perpendicular to wall
D. None of the above
Answer : A

24. During erection, the pile of length l is supported by a crane at a distance of
A. 0.207 l
B. 0.293 l
C. 0.707 l
D. 0.793 l From the driving end of pile which rests on the ground
Answer : C

25. 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

26. 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

27. A construction joint is provided where
A. Bending moment is small
B. Shear force is small
C. The member is supported by other member
D. All the above
Answer : D

28. In order to obtain the best workability of concrete, the preferred shape of aggregate is
A. Rounded
B. Elongated
C. Angular
D. All of the above
Answer : A

29. According to IS: 4561978, the flexural strength of concrete is
A. Directly proportional to compressive strength
B. Inversely proportional to compressive strength
C. Directly proportional to square root of compressive strength
D. Inversely proportional to square root of compressive strength
Answer : C

30. Slump test is done for
A. Clay
B. Sand
C. Lime
D. Concrete
Answer : D

31. The rock which is not calcareous, is:
A. Lime stone
B. Chalk
C. Laterite
D. None of these
Answer : D

32. 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

33. Ultimate strength of cold drawn high steel wires
A. Increases with increase in diameter of bar
B. Decreases with increase in diameter of bar
C. Does not depend on diameter of bar
D. None of the above
Answer : B

34. A concrete using an air entrained cement
A. Has strength less than 10% to 15%
B. Has more resistance to weathering
C. Is more plastic and workable
D. Is free from segregation and bleeding
Answer : C

35. 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

36. Strength of concrete with passage of time
A. Increases
B. Decreases
C. Fluctuates
D. Remains constant
Answer : A

37. If the slump of a concrete mix is 60 mm, its workability is
A. Very low
B. Low
C. Medium
D. High
Answer : C

38. According to Water-Cement Ratio Law, the strength of workable plastic concrete
A. Depends upon the amount of water used in the mix
B. Does not depend upon the quality of cement mixed with aggregates
C. Does not depend upon the quantity of cement mixed with aggregates
D. All the above
Answer : D

39. 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

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

41. 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

42. For an ordinary Portland cement
A. Residual does not exceed 10% when sieved through IS Sieve No. 9
B. Soundness varies from 5 to 10 mm
C. Initial setting time is not less than 30 minutes
D. Compressive stress after 7 days, is not less than 175 kg/cm²
Answer : C

43. 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 times; 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

44. If the average compressive strength is 4000 kg/cm2 and standard deviation is 500, the co-efficient of variation is
A. 10 %
B. 12.5 %
C. 15 %
D. 18.5 %
Answer : B

45. If aggregates completely pass through a sieve of size 75 mm and are retained on a sieve of size 60 mm, the particular aggregate will be flaky if its minimum dimension is less than
A. 20.5 mm
B. 30.5 mm
C. 40.5 mm
D. 50.5 mm
Answer : C

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

47. The size of fine aggregates does not exceed
A. 2.75 mm
B. 3.00 mm
C. 3.75 mm
D. 4.75 mm
Answer : D

48. 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

49. 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

50. When shear stress exceeds the permissible limit in a slab, then it is reduced by
A. Increasing the depth
B. Providing shear reinforcement
C. Using high strength steel
D. Using thinner bars but more in number
Answer : A