Quiznetik

Concrete Technology and Design | Set 3

1. Shrinkage in concrete can be reduced by using

Correct : D. all the above

2. The shuttering of a hall measuring 4 m × 5 m, can be removed after

Correct : B. 7 days

3. The approximate value of the ratio between direct tensile strength and flexural strength is

Correct : B. 0.5

4. An aggregate is said to be flaky if its least dimension is less than

Correct : C. 3/5th of mean dimension

5. Workability improved by adding

Correct : D. all the above

6. Workability of concrete is inversely proportional to

Correct : A. time of transit

7. Inert material of a cement concrete mix, is

Correct : C. aggregate

8. If a beam fails in bond, then its bond strength can be increased most economically by

Correct : B. using thinner bars but more in number

9. Pick up the incorrect statement from the following:

Correct : A. a rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive quantity of water

10. Ordinary Portland cement is manufactured from

Correct : B. gypsum and lime

11. The percentage of reinforcement in case of slabs, when high strength deformed bars are used is not less than

Correct : B. 0.12

12. Addition of pozzolana to cement

Correct : D. none of these

13. If 50 kg of fine aggregates and 100 kg of coarse aggregates are mixed in a concrete whose water cement ratio is 0.6, the weight of water required for harsh mix, is

Correct : C. 12 kg

14. The minimum cover to the ties or spirals should not be less than

Correct : C. 25 mm

15. According to Water-Cement Ratio Law, the strength of workable plastic concrete

Correct : D. all the above

16. Sands of zone I are:

Correct : A. course

17. According to Whitney's theory, ultimate strain of concrete is assumed to be

Correct : C. 0.3 %

18. The condition not applicable to water cement ratio law, is

Correct : B. concrete specimens may be tested at any temperature

19. If the slump of a concrete mix is 60 mm, its workability is

Correct : C. medium

20. Cube strength of controlled concrete to be used for pre-tensioned and post-tensioned work respectively should not be less than

Correct : B. 42 mpa and 35 mpa

21. The void ratio of

Correct : D. all the above

22. According to IS : 382-1963, a good aggregate should be

Correct : D. all the above

23. The compressive strength of 100 mm cube as compared to 150 mm cube is always

Correct : B. more

24. The diameter of the Vicat plunger is 10 mm and its length varies from

Correct : C. 40 mm to 50 mm

25. Gypsum is added for

Correct : C. controlling setting time

26. Modulus of elasticity of steel as per IS: 4561978 shall be taken as

Correct : C. 200 kn/mm²

27. The grade of concrete M 150 means that compressive strength of a 15 cm cube after 28 days, is

Correct : B. 150 kg/cm2

28. The cement becomes useless if its absorbed moisture content exceeds

Correct : D. 5 %

29. In reinforced concrete footing on soil, the minimum thickness at edge should not be less than

Correct : B. 150 mm

30. For preparing a test-specimen, it is necessary

Correct : D. all the above

31. For a good concrete

Correct : D. all the above

32. The process of hardening the concrete by keeping its surface moist is known

Correct : C. curing

33. For the construction of the retaining structures, the type of concrete mix to be used, is

Correct : C. 1 : 1½ : 3

34. The produce impermeable concrete

Correct : D. all the above

35. Pozzolanic properties exist in

Correct : D. all the above

36. A continuous beam is deemed to be a deep beam when the ratio of effective span to overall depth (1/D) is less than

Correct : C. 2.5

37. Pick up the correct statement from the following:

Correct : D. all the above

38. If fineness modulus of sand is 2.5, it is graded as

Correct : B. fine sand

39. Maximum quantity of water needed per 50 kg of cement for M 15 grade of concrete is

Correct : C. 32 liters

40. The increased cohesiveness of concrete, makes it

Correct : A. less liable to segregation

41. Concrete is unsuitable for compaction by a vibrator if it is

Correct : D. plastic

42. In order to obtain the best workability of concrete, the preferred shape of aggregate is

Correct : A. rounded

43. Hydration of cement is due to chemical action of water with

Correct : D. all the above

44. An aggregate which passes through 25 mm I.S. sieve and is retained on 20 mm sieve, is said to be flaky if its least dimension is less than

Correct : D. 13.5 mm

45. Approximate value of shrinkage strain in concrete, is

Correct : B. 0.0003

46. For quality control of Portland cement, the test essentially done is

Correct : D. all the above

47. Strength of concrete with passage of time

Correct : A. increases

48. Which of the following statements is incorrect?

Correct : D. none of the above

49. To obtain cement dry powder, lime stones and shales or their slurry, is burnt in a rotary kiln at a temperature between

Correct : D. 1400° and 1500°c

50. In a pile of length , the points of suspension from ends for lifting it are located at

Correct : A. 0.207 l

51. Curing a concrete for long period ensures better

Correct : D. all the above

52. Batching error means inaccuracy in the quantity of

Correct : D. all the above

53. If the storey height is equal to length of RCC wall, the percentage increase in strength is

Correct : B. 10

54. 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

Correct : B. p = [(x - z)/(z - y)] × 100

55. If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called

Correct : C. over-reinforced beam

56. Proper proportioning of concrete, ensures

Correct : D. all the above

57. The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by

Correct : B. fcr > fcs > fcl

58. Air entrainment in the concrete increases

Correct : A. workability

59. Construction joints are provided

Correct : D. all the above

60. Maximum distance between expansion joints in structures as per IS: 456 1978 is

Correct : C. 45 m

61. Ordinary concrete is not used for concrete grade

Correct : D. m 400

62. In a spherical dome subjected to concentrated load at crown or uniformly distributed load, the meridional force is always

Correct : C. compressive

63. An aggregate is said to be flaky, if its least dimension is less than

Correct : C. 3/5 mean dimension

64. While designing an air entrained concrete

Correct : D. all the above

65. Minimum thickness of load bearing RCC wall should be

Correct : B. 100 mm

66. M 150 grade of concrete approximates

Correct : B. 1 : 1 :2 mix

67. Permissible compressive strength of M 300 concrete grade is

Correct : D. 300 kg/cm2

68. Strength of concrete increases with

Correct : B. increase in fineness of cement

69. For ensuring quality of concrete, use

Correct : C. graded aggregates

70. In working stress design, permissible bond stress in the case of deformed bars is more than that in plain bars by

Correct : D. 40 %

71. Workability improved by adding

Correct : D. all the above

72. The rock which is not calcareous, is:

Correct : D. none of these

73. A T-shaped retaining wall mainly consists of

Correct : C. three cantilevers

74. Pick up the correct statement from the following:

Correct : D. all the above

75. The fineness modulus of fine aggregate is in the range of

Correct : A. 2.0 to 3.5

76. After casting, an ordinary cement concrete on drying

Correct : C. shrinks

77. The most commonly used admixture which prolongs the setting and hardening time is

Correct : A. gypsum

78. For given water content, workability decreases if the concrete aggregates contain an excess of

Correct : D. all the above

79. The process of proper and accurate measurement of concrete ingredients for uniformity of proportion, is known

Correct : D. batching

80. The load factors for live load and dead load are taken respectively as

Correct : B. 2.2 and 1.5

81. The mixture of different ingredients of cement, is burnt at

Correct : C. 1400°c

82. In case of hand mixing of concrete, the extra cement to be added is

Correct : B. 10 %

83. If 1500 g of water is required to have a cement paste 1875 g of normal consistency, the percentage of water is,

Correct : B. 25 %

84. The percentage of voids in cement is approximately

Correct : B. 40 %

85. Water required per bag of cement, is

Correct : D. 35 kg

86. The recommended value of modular ratio for reinforced brick work is

Correct : C. 40

87. For an ordinary Portland cement

Correct : C. initial setting time is not less than 30 minutes

88. The ratio of the diameter of reinforcing bars and the slab thickness is

Correct : D. 1/8

89. Pozzolana cement is used with confidence for construction of

Correct : D. all the above

90. Pick up the correct statement from the following:

Correct : D. both (b) and (c)

91. The operation of removing humps and hollows of uniform concrete surface, is known as

Correct : B. screeding

92. 1% of voids in a concrete mix would reduce its strength by about

Correct : A. 5 %

93. For a continuous slab of 3 m × 3.5 m size, the minimum overall depth of slab to satisfy vertical deflection limits is

Correct : B. 75 mm

94. The most useless aggregate is one whose surface texture is

Correct : C. glassy

95. The shrinkage of concrete

Correct : D. all the above

96. The maximum thickness of concrete floor of a cement warehouse, is

Correct : D. 25 cm

97. Too wet concrete may cause

Correct : D. all the above

98. Maximum percentage reinforcement in case of slabs is limited to

Correct : B. 4

99. The commonly used material in the manufacture of cement is

Correct : C. lime stone

100. According to I.S. : 456, the number of grades of concrete mixes, is

Correct : D. 7