RRB NTPC - Concrete Technology and Design 1000+ MCQ [Solved] PDF Download

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

2. Pick up the correct statement from the following:
A. The weight of ingredients of concrete mix, is taken in kilograms
B. Water and aggregates are measured in litres
C. 20 bags of cement make one tonne
D. All the above
Answer : D

3. 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

4. Increase in the moisture content in concrete
A. Reduces the strength
B. Increases the strength
C. Does not change the strength
D. All of the above
Answer : A

5. 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

6. Too wet concrete may cause
A. Weakness of concrete
B. Excessive laitance
C. Segregation
D. All the above
Answer : D

7. Stress strain curve of high tensile steel
A. Has a definite yield point
B. Does not show definite yield point but yield point is defined by 0.1% proof stress
C. Does not show definite yield point but yield point is defined by 0.2% proof stress
D. Does not show definite yield point but yield point is defined by 2% proof stress,
Answer : C

8. 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

9. 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

10. The load factors for live load and dead load are taken respectively as
A. 1.5 and 2.2
B. 2.2 and 1.5
C. 1.5 and 1.5
D. 2.2 and 2.2
Answer : B

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

12. If 20 kg of coarse aggregate is sieved through 80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron and 150 micron standard sieves and the weights retained are 0 kg, 2 kg, 8 kg, 6 kg, 4 kg respectively, the fineness modulus of the aggregate, is
A. 7.30
B. 7.35
C. 7.40
D. 7.45
Answer : C

13. The bulk density of aggregates does not depend upon:
A. Size and shape of aggregates
B. Specific gravity of aggregates
C. Grading of aggregates
D. Size and shape of the container
Answer : D

14. The load carrying capacity of a helically reinforced column as compared to that of a tied column is about
A. 5 % less
B. 10 % less
C. 5 % more
D. 10 % more
Answer : C

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

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

17. Strength of concrete increases with
A. Increase in water-cement ratio
B. Increase in fineness of cement
C. Decrease in curing time
D. Decrease in size of aggregate
Answer : B

18. The entrained air in concrete
A. Increases workability
B. Decreases workability
C. Decreases resistance to weathering
D. Increases strength
Answer : A

19. Most common method of pre-stressing used for factory production is
A. Long line method
B. Freyssinet system
C. Magnel-Blaton system
D. Lee-Macall system
Answer : A

20. For a reinforced concrete section, the shape of shear stress diagram is
A. Wholly parabolic
B. Wholly rectangular
C. Parabolic above neutral axis and rectangular below neutral axis
D. Rectangular above neutral axis and parabolic below neutral axis
Answer : C

21. 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

22. 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

23. In T-shaped R C. retaining walls, the main reinforcement in the stem is provided on
A. The front face in one direction
B. The front face in both directions
C. The inner face in one direction
D. The inner face in both directions
Answer : C

24. 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

25. The grade of concrete not recommended by I.S. : 456, is
A. M 100
B. M 200
C. M 300
D. M 500
Answer : D

26. An aggregate is said to be flaky if its least dimension is less than
A. 1/5th of mean dimension
B. 2/5th of mean dimension
C. 3/5th of mean dimension
D. 4/5th of mean dimension
Answer : C

27. 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

28. Vicat's apparatus is used for
A. Fineness test
B. Consistency test
C. Setting time test
D. Soundness test
Answer : B

29. 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

30. 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

31. Pick up the incorrect statement from the following:
A. Concrete for which preliminary tests are conducted, is called controlled concrete
B. Bulking of sand depends upon the fineness of grains
C. Concrete mix 1 : 6 : 12, is used for mass concrete in piers
D. All the above
Answer : D

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

33. 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

34. 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

35. 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

36. Minimum pitch of transverse reinforcement in a column is
A. The least lateral dimension of the member
B. Sixteen times the smallest diameter of longitudinal reinforcement bar to be tied
C. Forty-eight times the diameter of transverse reinforcement
D. Lesser of the above three values
Answer : D

37. 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

38. 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

39. 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

40. 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

41. Concrete mainly consists of
A. Cement
B. Aggregates
C. Water
D. All the above
Answer : D

42. 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

43. 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

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

45. 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

46. 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

47. Workability of concrete is inversely proportional to
A. Time of transit
B. Water-cement ratio
C. The air in the mix
D. Size of aggregate
Answer : A

48. 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

49. If the size of panel in a flat slab is 6 m × 6 m, then as per Indian Standard Code, the widths of column strip and middle strip are
A. 3.0 m and 1.5 m
B. 1.5 m and 3.0 m
C. 3.0 m and 3.0 m
D. 1.5 m and 1.5 m
Answer : C

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