Quiznetik

Concrete Technology | Set 4

1. The sum of the percentage of tricalcium silicate and dicalcium silicate for Portland cement varies from

Correct : C. 70 to 80%

2. The percentage of water for making a cement paste of normal consistency varies from

Correct : B. 25 to 35%

3. Vertical sides of columns may be stripped after

Correct : A. 1 to 2 days

4. Rapid hardening cement is used

Correct : D. all of the above

5. If 30% excess water is added, the strength of concrete is reduced by

Correct : C. 50%

6. Which of the following statement is correct while compacting concrete with vibrators?

Correct : C. The vibrator should not touch the form surface.

7. The slump test of concrete is used to mesure its

Correct : A. consistency

8. The importance of storing the various ingredients of concrete is

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

9. The resistance of an aggregate to wear is known as

Correct : C. abrasion value

10. The magnesium oxide and sulphur dioxide when added in excess quantity makes the cement unsound.

Correct : A. Correct

11. The minimum quantity of cement to be used in controlled concrete is specified as

Correct : C. 220 kg / cm3

12. The aggregates of rounded shape require minimum cement paste to make good concrete.

Correct : A. True

13. For performing the compressive strength test of cement, the size of cube mould should be 7.06 cm side.

Correct : A. Right

14. The value of finencess modulus for fine sand may range between

Correct : D. 2.2 to 2.6

15. The final operation of finishing the concrete surface is called

Correct : C. trowelling

16. Segregation of concrete increases the strength of concrete.

Correct : B. No

17. The resistance of an aggregate to compressive forces is known as

Correct : A. crushing value

18. According to the rule of water cement ratio, the strength of concrete wholly depends upon

Correct : C. the amount of water used in preparation of concrete mix

19. The process of proper and accurate measurement of all concrete materials for uniformity of proportions and aggregate grading is called

Correct : D. batching

20. The minimum particle size of coarse aggregate is

Correct : B. 4.75 mm

21. The concrete without any reinforcement has

Correct : A. low

22. A mix with water-cement ratio of 0.78 is termed as wet mix.

Correct : A. Yes

23. Cement concrete is

Correct : B. impermeable

24. Vicat's apparatus is used to perform

Correct : C. consistency test

25. The presence of lime in cement

Correct : B. provides strength to the cement

26. The construction joints in cement concrete

Correct : C. should not be provided at the corners

27. During field test, the cement is said to be pure and of good quality when

Correct : D. all of the above

28. A good concrete should have minimum thermal expansion.

Correct : A. Yes

29. Workability of concrete mix having very low water-cement ratio should be obtained by

Correct : C. compaction factor test

30. The process of removing the irregularities from the surface of concrete left after screeding is called floating.

Correct : A. Correct

31. Each layer of concrete placed in the mould, in preliminary test, is compacted 25 times with a 20 mm diameter rod and 60 cm in length

Correct : B. Wrong

32. "Colocrete" is the commercial term for

Correct : B. coloured cement

33. In transportation of concrete by pumps

Correct : D. all of the above

34. When the batching of material is done by weight

Correct : D. all of the above

35. The workability of concrete can be improved by adding

Correct : D. all of these

36. In order to provide colour, hardness and strength to the cement, the ingredient used is

Correct : D. iron oxide

37. In performing the works test

Correct : D. all of the above

38. The proportion of lime, silica, alumina and iron oxide in a good Portland cement should be

Correct : A. 63 : 22 : 6 : 3

39. The process of consolidating concrete mix after placing it in position is termed as

Correct : C. compaction

40. The main object of proportioning concrete is to obtain

Correct : D. all of these

41. If the water cement ratio is more, then the

Correct : D. all of the above

42. After the final grinding, the cement is sieved through IS sieve number

Correct : A. 9

43. Blast furnace slag cement

Correct : E. Both (a) and (b)

44. The change of state of cement paste from fluid to solid is called hardening.

Correct : B. Wrong

45. The compaction factor is the ratio of weight of partially compacted concrete to the weight of fully compacted concrete.

Correct : A. Yes

46. Argillaceous materials contain

Correct : C. alumina

47. If the proportions of different ingredients (cement, sand and aggregate) are in the ratio of 1 : 2 : 4, then the grade of concrete is

Correct : B. M 15

48. The rule of water cement ratio was established by

Correct : A. Duff Abram

49. The impact value of an aggregate is generally used as an alternative to its crushing value, to know the quality of aggregate.

Correct : A. Yes

50. The workability of concrete is expressed by

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

51. The most useless aggregate is, whose surface texture is

Correct : B. glossy

52. High temperature

Correct : B. decreases

53. A suitable admixture added at the time of preparing the concrete mix, makes the concrete.

Correct : D. all of these

54. A moist aggregate is one

Correct : A. whose all the pores are filled with water and also having its surface wet

55. The finer the sand, greater is the bulkage.

Correct : A. Correct

56. The fineness of cement is measured in terms of

Correct : C. either (a) or (b)

57. For the manufacture of concrete of low density, the aggregate used is

Correct : D. all of these

58. The value of bulk density of the aggregate depends upon

Correct : D. all of these

59. High percentage of tricalcium silicate and low percentage of dicalcium silicate in cement results in

Correct : D. none of these

60. When vibrators are used for compaction, the consistency of concrete depends upon the

Correct : D. all of these

61. Reinforced cement concrete is equally strong in taking

Correct : C. tensile, compressive and shear stresses

62. The process of mixing, transporting, placing and compacting the cement concrete should not take more than

Correct : A. 30 minutes

63. The material having particle size varying from 0.002 to 0.06 mm is termed as

Correct : A. silt

64. The strength of cement concrete increases with the increase of water cement ratio.

Correct : A. Agree

65. The bulk density of aggregates depends upon its

Correct : D. all of these

66. The main requirement, which a ware-house should fulfil is that

Correct : E. Both (a) and (b)

67. If the slump of the concrete mix is less than 50 mm, then while compacting it with vibratiors, the segregation will not take place.

Correct : A. Right

68. The compressive strength of an ordinary Portland cement (1 : 3 cement mortar cube) after 7 days test should not be less than

Correct : B. 17.5 N/mm2

69. If mineral oil is present in mixing water for concrete, it increases strength for a concentration upto 2 percent.

Correct : A. Yes

70. Concrete with higher compaction factor has less workability.

Correct : A. True

71. The aggregates of

Correct : C. rounded

72. The Indian standard code specifies that the crushing strength for which the mix should be designed in the laboratory should be

Correct : A. 1.25

73. For batching 1 : 2 : 4 concrete mix by volume, the ingredients required per bag of cement are

Correct : B. 50 kg of cement : 70 litres of fine aggregate : 140 litres of coarse aggregate

74. For heat and sound insulation purposes, we shall use

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

75. The strength and durability of concrete depends upon

Correct : D. all of these

76. Which of the following statement is wrong?

Correct : B. An admixture cannot increase the workability of concrete without increasing water content.

77. Insufficient quantity of water

Correct : B. makes the concrete mix unworkable

78. In the manufacture of cement, the dry or wet mixture of calcareous and argillaceous materials is burnt at a temperature between

Correct : D. 1500?C to 1600?C

79. The practical utility of concrete technology for civil engineers is to

Correct : D. all of the above

80. Water-cement ratio is, usually, expressed in

Correct : A. litres of water required per bag of cement

81. With the moisture content of 5 to 10% by weight, the bulking of sand is increased by

Correct : D. 50%

82. For continuous transportation of concrete, the method used is

Correct : C. transport of concrete by belt concrete conveyors

83. Which of the following statement is correct?

Correct : A. Duff Abram's law is valid only when the concrete is of workable plasticity.

84. The function of aggregates in concrete is to serve as

Correct : B. filler

85. The breaking up of cohesion in a mass of concrete is called

Correct : C. segregation

86. The Vee-Bee test is suitable for concrete mixes of low and very low workabilities.

Correct : A. True

87. The aggregate which pass through 4.75 mm IS sieve and entirely retain on 75 micron IS sieve is called

Correct : C. fine aggregate

88. Efflorescence in cement is caused due to the excess of

Correct : C. alkalies

89. Which of the following grade is not recommended by IS 456-1978?

Correct : D. M 55

90. The deleterious materials present in the aggregate

Correct : D. all of the above

91. Ferro-concrete is another name given to

Correct : B. reinforced cement concrete

92. The use of air-entraining agents in concrete

Correct : D. all of these

93. The characteristic, which makes the concrete a versatile and widely used material of modern consturction, is the possibility of

Correct : D. all of the above

94. The concrete in which no preliminary tests are performed for designing the mix is called

Correct : D. ordinary concrete

95. The cement concrete having water-cement ratio less than 0.45 by weight, causes honey-comb structure.

Correct : B. Incorrect

96. The workability of concrete is defined as the

Correct : A. ease with which it can be mixed, transported and placed in position in a homogeneous state

97. Low heat cement is used in

Correct : B. thick

98. The removal of excess air after placing concrete helps in increasing the strength of concrete by

Correct : A. 15 to 20%

99. In voids method of determining the quantity of cement paste, it is assumed that the

Correct : D. all of the above

100. The mass concrete in piers and abutments, the grade of concrete mix used, is

Correct : D. 1 ; 3 : 6