Quiznetik

Concrete Technology | Set 3

1. If the aggregate completely passes through a 50 mm sieve and retained on 40 mm sieve, then the particular aggregate is said to be flaky if its least dimension is less than

Correct : A. 27 mm

2. Which of the following statement is correct?

Correct : D. all of the above

3. For highly loaded columns, the concrete mix used is of proportion

Correct : A. 1 ; 1 : 2

4. The importance of batching is to obtain

Correct : D. all of these

5. Harshness in concrete is due to the excess of

Correct : C. middle sized particle

6. Bulking of sand is

Correct : C. increase in volume of sand due to presence of moisture upto certain extent

7. If the fineness modulus of sand is 3, then the sand is graded as

Correct : D. coarse sand

8. More water should not be added in the concrete mix, as to increase

Correct : C. water-cement ratio

9. The concrete mix is said to be workable if it has

Correct : D. all of these

10. The maximum particle size of fine aggregate is

Correct : B. 4.75 mm

11. The size of an aggregate is determined by length gauge.

Correct : B. No

12. The aggregate is said to be flaky when

Correct : A. its least dimension is three-fifth of its mean dimension

13. In designing a ware-house, it is assumed that

Correct : D. all of the above

14. The concrete

Correct : A. should

15. The strength of concrete using air entraining cement gets reduced by

Correct : B. 10 to 15%

16. A compaction factor of 0.88 indictes that the workability of concrete mix is

Correct : C. medium

17. In order to prepare a test specimen, it is necessary to

Correct : D. all of the above

18. In the manufacture of possolana cement, the amount of pozzolana material added to ordinary Portland cement clinkers is about

Correct : B. 30%

19. The usual proportion of ingredients in plain cement concrete is

Correct : A. Portland cement (1 part), clean sand (1

20. The arbitrary mix method, the coarse aggregates are taken twice the fine aggregates.

Correct : A. True

21. At freezing point, the concrete sets easily.

Correct : B. Wrong

22. Too much finencess of cement

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

23. In making precast structural units for partition and wall lining purposes, the concrete should be

Correct : C. light-weight concrete

24. Calcareous material used in the manufacture of cement consists of

Correct : D. all of these

25. Los Angeles machine is used to perform the abrasion resistance test of an aggregate.

Correct : A. Right

26. The workability of concrete mix increases with the increase in moisture content.

Correct : A. Agree

27. Ordinary Portland cement should not be used for construction work exposed to sulphates in the soil.

Correct : A. Agree

28. According to IS : 269 - 1976, the requirement of an ordinary Portland cement is that

Correct : D. all of the above

29. The 'first-in, first-out' rule should eb applied when cement hags are to be removed from the ware-house.

Correct : A. True

30. The placement of concrete should be discontinued during rainy periods

Correct : A. Yes

31. The mixer, which produces a steady stream of concrete as long as it is in operation, is known as

Correct : C. continuous mixer

32. The cement concrete, from which entrained air and excess water are removed after placing it in position, is called

Correct : A. vacuum concrete

33. Which of the following statement is wrong?

Correct : D. none of the above

34. In the slump test, the maximum size of the aggregate should not exceed 38 mm.

Correct : A. Correct

35. Hydration of cement evolves heat.

Correct : A. True

36. Pezzolana is essentially a silicious material containing clay upto

Correct : D. 80%

37. An aggregate is said to be

Correct : C. cyclopean

38. When the sand is fully saturated, its volume is

Correct : A. equal to

39. The resistance of an aggregate to sudden compressive forces is called impact value.

Correct : A. Correct

40. The controlled concrete is used for

Correct : D. all the seven grades of concrete mix

41. The admixtures are added in concrete to

Correct : D. all of the above

42. The aggregate is said to be elongated when

Correct : D. its length is equal to 1.8 times its mean dimension

43. The maximum particle size of coarse aggregate is

Correct : D. 75 mm

44. The cement, widely used in retaining walls, is

Correct : B. low heat cement

45. The presence of tricalcium silicate in cement

Correct : A. hydrates the cement rapidly

46. If sea water is used for preparing concrete mix, it

Correct : D. all of these

47. Which of the following statement is correct?

Correct : D. all of the above

48. Vibrated concrete needs

Correct : A. less

49. Alumina in the cement lowers the clinkering temperature.

Correct : A. Agree

50. The concrete can be lifted by pumps through a maximum vertical distance of

Correct : D. 50 m

51. The diameter of the pipe line used for transportation of concrete by pumps should not exceed

Correct : C. 30 cm

52. The inert mineral material used for the manufacture of mortars and concretes is

Correct : C. aggregate

53. Which of the following cements is expected to have the highest compressive strength after 3 days.

Correct : C. high alumina cement

54. In the manufacture of cement, the dry or wet mixture of calcareous and argillaceous materials is burnt in a

Correct : C. rotary kiln

55. The knowledge of a standard consistency of a cement paste is essential to perform

Correct : D. all of these

56. The placing of concrete should start width-wide in reinforced cement concrete slabs from one end.

Correct : A. True

57. The separation of water or water-cement mixture from the freshly mixed concrete is known as bleeding.

Correct : A. True

58. The phenomenon by virtue of which the cement does not undergo large change in volume when treated with water, is known as

Correct : B. soundness

59. The concrete in which preliminary tests are performed for designing the mix is called

Correct : B. controlled concrete

60. The type of lime used in lime concrete is

Correct : D. hydraulic lime

61. Segregation in concrete results in

Correct : D. all of these

62. The sum of percentages of all deleterious materials in the aggregate shall not exceed

Correct : A. 5%

63. In Vicat's apparatus, the diameter of Vicat plunger is

Correct : B. 10 mm

64. Tricalcium silicate develops strength in cement for first 7 days.

Correct : A. Yes

65. Which of the following statement is correct?

Correct : D. all of the above

66. The presence of dicalcium silicate in cement

Correct : D. all of these

67. The usual proportion of ingredients in reinforced cement concrete is

Correct : B. Portland cement (1 part), clean sand (1 to 2 parts) and coarse aggregate (2 to 4 parts)

68. Trowelling should be finished on the same day of its laying operation.

Correct : A. Yes

69. The continuous strain, which the concrete undergoes due to application of external loads, is called

Correct : D. creep

70. The value of bulk density for angular and flaky aggregates is

Correct : B. less

71. The development of first 28 days strength is on account of the hydration of

Correct : B. tricalcium silicate

72. The resistance of an aggregate to the effect of hydration of cement and weather is called

Correct : D. soundness

73. For reinforced cement concrete lintels and slabs, the nominal size of coarse aggregate should not exceed.

Correct : B. 15 mm

74. The slump whould not exceed 50 mm when compacting concrete with vibrators.

Correct : A. Agree

75. The bulk density of an aggregate is the weight required to fill a container of unit volume.

Correct : A. Agree

76. Which of following proportion of different ingredient of concrete mix confirm to the arbitrary mothod of mixing?

Correct : C. 1 : 4 ; 8

77. The levelling operation that removes humps and hollows and give a true, uniform concrete surface is called

Correct : A. screeding

78. The apparent specific gravity of an aggregate is defined as

Correct : A. the weight of oven dry aggregate divided by its absolute volume, excluding the natural pores in the aggregate particles

79. In concrete walls, construction joints should be provided at the

Correct : D. all of these

80. According to IS : 383 - 1970, a good a aggregate for concrete construction should be

Correct : D. all of these

81. If the effective plan area of a warehouse is 54 m2, and the maximum height of pile permitted is 2.7 m, then the number of cement bags to be stord is

Correct : D. 2700

82. A good concrete should be subjected to

Correct : B. minimum

83. The hardening is the phenomenon by virtue of which

Correct : C. the cement paste sets and develops strength

84. Under normal circumstances, the beam soffits may be removed after

Correct : B. 7 days

85. The ratio of different ingredients (cement, sand and aggregate) in concrete mix of grade M 20 is

Correct : B. 1 ; 1.5 : 3

86. The concrete mix of grade M 25 means that the compressive strength of 15 cm cubes at 28 days after mixing is

Correct : C. 25 N/mm2

87. The measuring 50 litres of aggregate, the inner dimensions of a farma should be

Correct : D. 31 cm x 31 cm x 52 cm

88. The test conducted in the laboratory on the specimen made out of trial concrete mix is called

Correct : A. preliminary test

89. The capcity of a ware-house depends upon the

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

90. For high degree of workability, the compaction factor is

Correct : D. 0.95

91. The ratio of the volume of moist sand to the volume of dry sand is known as

Correct : C. bulking factor

92. The object of curing is to

Correct : D. all of these

93. The process of hardening the concrete mixes by keeping its surface moist for a certain period is called

Correct : B. curing

94. The prevent the cement bags from any possible contact with moisture, the main point that should be kept in mind is that the

Correct : D. all of the above

95. According to Indian standard specifications for the compressive strength test of cement, the cement and standard sand mortar in the ratio of

Correct : C. 1 ; 3

96. Which of the following statement is correct?

Correct : D. all of the above

97. Lime when added in excess quantity

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

98. The standard sand now used in India is obtained from

Correct : A. Ennore (Chennai)

99. Initial setting time of ordinary Portland cement is

Correct : B. 30 min

100. The preliminary test should be repeated if the difference of compressive strength of three test specimens exceeds

Correct : C. 1.5 N / mm2