Top 151 QnA of Concrete Technology to Crack | MCQ for Concrete Tech.

Top 151 QnA of Concrete Technology to Crack | MCQ for Concrete Tech.

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

a) sand stone                                         b) slate

c) lime stone                                          d) graphite

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

a) 1100°C and 1200°C                        b) 1200°C and 1300°C

c) 1300°C and 1400°C                        d) 1400°C and 1500°C

3. How much cement contained in one bag 

a) 5000 N                                             b) 250 N

c) 500 N                                               d) 300 N

4. The maximum quantity of ingredients present in cement production is

a) lime                                                 b) silica

c) alumina                                          d) iron oxide

5. The minimum percentage of chemical ingredient of cement is 

a) alumuna                                        b) iron oxide

c) silica                                               d) lime

6. The minimum percentage of chemical ingredient of cement is that of

a) magnesium oxide                       b) iron oxide

c) aluminium                                   d) lime 

7. Pick up the correct proportions of chemical ingredients of cement

a) Lime: Silica: Alumina: Iron oxide: 63: 22: 6:3

b) Silica: Lime: Alumina: Iron oxide: 63: 22: 6:3

c) Alumina: Silica: Lime: Iron oxide: 63; 22: 6:3

d) Iron oxide: Alumina: Silica: Lime: 63: 22: 6:3

8. Pick up the correct statement from the following:

a) lime in excess, causes the cement to expand and disintegrate 

b) silica in excess, causes the cement to set slowly

c) alumina in excess, reduces the strength of the cement 

d) magnesium oxide in excess, remains in free state and makes the   cement unsound

e) all of the above

9. Efflorescence in cement is caused due to an excess of

a) alumina                                     b) iron oxide

c) silica                                           d) alkalis

10. 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%

11. Pick up the incorrect statement from the following:

a) gypsum in cement decreases the setting time

b) the first compound of cement which reacts with water, is

c) bulking of sand is less when its particles are fine

d) all of the above

12. Cement used for normal concrete construction, is obtained by burning a mixture of

a) silicious and argillaceous materials  

b) argillaceous and calcareous materials

c) silicious and calcareous materials 

d) silicious, argillaceous and calcareous materials

13 The mixture of different ingredients of cement, is burnt at 

a) 1000°C                                        b) 1200°C

c) 1400°C                                        d) 1600°C

14. The cement whose strength is 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

15. For construction of structures in sea water, the cement generally preferred to, is

a) protland pozzolona cement

b) quick setting cement

c) low heat portland cement 

d) rapid hardening cement

16. For quality control of portland cement, the test essentially done is 

a) setting time                                      b) soundness 

c) tensile strength                               d) consistency 

e) all of the above

17. Sieve analysis of portlad cement is performed on IS sieve No. 

a) 3                                                        b) 5

c) 7                                                        d) 9

18. During manufacturing process of portland cement, gypsum or plaster of Paris is added 

a) to increase the strength of cement 

b) to modify the color of cement 

c) to adjust the setting time of cement  

d) to reduce heat of hydration

19. The percentage of gypsum added to the clinker during manufacturing process is 

a) 0.20                                                   b) 0.25 to 0.35

c) 0.35 to 5.0                                        d) 5 to 10

20. Addition of sugar in concrete results in 

a) increase in setting time by about 1 hour

b) increase in setting time by about 4 hours 

c) decrease in setting time by about 1 hour 

d) decrease in setting time by about 4 hour

21. Setting time of concrete decreases by adding 

a) gypsum                                          b) hydrogen peroxide 

c) calcium chloride                           d) sodium oxide

22. The minimum initial setting time of ordinary portland cement is 

a) 1 hr                                                 b) 2 hrs

c) 15 minutes                                    d) 30 minutes 

23. Addition of pozzolana to ordinary portland cement, causes 

a) decrease in early strength  

b) reduction in chemical action with sulphates 

c) increase inshrinkage 

d) reduction in bleeding 

e) all of the above

24. Addition of pozzolana to cement 

a) decrease workability 

b) increase strength 

c) increase heat of hydration 

d) decrease curing time 

e) none of the above

25. Pozzolana cement is used with confidence for

a) dams                                                 b) massive foundation    

c) abutments                                       d) R.C.C. structures

e) all of the above

26. Slag cement is used is

a) dam                                                   b) abutment 

c) RCC                                                    d) none of the above

27. Pick up the correct statement from the following:

a) insufficient quantity of water makes the concrete mix harsh 

b) insufficient quantity of water makes the concrete unworkable

c) excess quantity of water makes the concrete segregated

d) excess quantity of water cause bleeding in concrete

e) all of the above

28. Pick up the incorrect statement from the following: 

a) Tricalcium silicate (C3S) hydrates rapidly

b) Tricalcium silicate (C3S) generates more heat of hydration

c) Tricalcium silicate (C3S) develops early strength 

d) Tricalcium silicate (C3S) has more resistance to sulphate

attack

29. Di-calcium silicate (C₂S) 

a) hydrates rapidly

b) generates less heat of hydration

c) hardens rapidly

d) provides bad ultimate strength to cement

30. Tri-calcium aluminate (C3A)

a) reacts fast with water

b) generates max heat of hydration

c) hardness rapidly

d) provides bad ultimate strength to cement

31. 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 C₂Scontribute to slow hardening 

d) low percentage of C3S and high percentage of C₂S provide greater resistance to chemical attack

e) all of the above

32.Pick up the incorrect statement from the following: 

a) the degree of grading of cement, is called fineness

b) the process of changing cement paste into hard mass, is known as setting of cement

c) the phenomenon by virtue of which cement does not allow transmission of sound, is known as soundness of cement 

d) the heat generated during chemical reaction of cement with water, is known as heat of hydration

33. When water is added to cement

a) heat is generated 

b) heat is absorbed

c) chemical reaction is absorbed 

d) impurities are washed out

34. The development of strength of cement and its fineness are 

a) directly proportional                               b) inversely proportional

c) randomly related                                     d) not related

35. The increase in the strength of concrete with time is 

a) linear                                                         b) non-linear

c) asympotic                                                 d) all of the above

36. For ordinary portland cement 

a) residual does not exceed 10% when sieved through IS sieve No. 9

b) soundness varies from 5 to 10

c) initial setting time is not less than 30 minutes

d) compressive stress after 7 days, is not less than 175kg/cm² 

e) all of the above 

37. The initial and final setting times of ordinary Portland cement are approximately related are

a) T = 540 + t                                                 b) T = 270+t     

c) T = 90+1.2t                                                d) T = 90+ t

Where T and t are final and initial setting time.

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

a) tricalcium silicate and dicalcium silicate

b) dicalcium silicate and tricalcium aluminate 

c) tricalcium aluminate and tricalcium alumino ferrite

d) all of the above

39. Hardening of cement occurs at

a) rapid rate during the first few days and afterwards it continues to increase at a decreased rate

b) slow rate during the first few days and afterwards it continues to increase at a rapid rate 

c) uniform rate throughout its age

d) none of the above

40. Density of ordinary portland cement is

a) 1.2-1.4t/m³                                             b) 1.4-1.5t/m³ 

c) 1-5-1.6t/m³                                             d) none of the above

41. The high strength of rapid hardening cement at early stage, is due to

a) finer grinding

b) burning at high temperature

c) increased lime cement 

d) higher content of tricalcium

42. 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

43. You are asked to construct a massive dam, the type of cement you will use, is

a) ordinary portland cement 

b) rapid hardening cement

c) low heat cement

d) blast furnace slag cement

44. The commercial name of white and coloured cement in India, is

a) colocrete

b) rainbow cement

c) silvicrete, snowcem

d) all of the above

45. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is

a) 30%                                                            b) 40%

c) 50%                                                            d) 60%

46. Pick up the correct statement from the following:

a) calcium chloride acts as a retarder 

b) gypsum (calcium sulphate) acts as an accelerator

c) gypsum (calcium sulphate) acts as a retarder 

d) calcium chloride acts as an accelerator

e) both (c) and (d) of above

47. For the construction of thin R.C.C. structure, the type of

cement to be avoided, is 

a) ordinary portland cement

b) rapid hardening cement

c) low heat cement

d) blast furnace slag cement

48. Sand generally contains salt if it is obtained from

a) nala beds                                         b) river beds

c) sea beds                                           d) all of the above

49. The presence of common salt in sand results in

a) corrosion of reinf

b) scaling

c) pitting

d) all of the above

50. Bulking of sand is

a) mixing of different sizes of sand particles 

b) mixing of lime with sand

c) mixing water with sand

d) swelling of sand when wetted

51. Bulking of coarse aggregate is 

a) less as compared to that of sand

b) more as compared to that of sand 

c) 15% at 4% moisture content

d) negligible

52. San d requiring a high water cement ratio, belongs to

a) zone I                                                 b) zone II

c) zone III                                               d) zone IV

53. Sands of zone I are

a) coarse                                               b) medium

c) medium to fine                               d) fine

54. Fineness modulus modulus of fine aggregate is between 

a) 2-3.5                                                 b) 3.5-5.0

c) 5.0-6.0                                              d) 6.0-7.5

55. The size of fine aggregates does not exceed

a) 2.75 mm                                          b) 3.00 mm

c) 3.75 mm                                          d) 4.75 mm

56. The function of fine aggregate is:

a) to assist in producing workability and uniformity in the Mixture

b) to assist the cement paste to hold the coarse aggregate particles in suspension

c) to promote plasticity in the mixture and prevent possible segregation of paste and coarse aggregate 

d) all of the above

57. An aggregate should

a) be of proper shape and size

b) be clean, hard and well graded

c) possess chemical stability

d) all of the above

58. An aggregate generally should not preferred for use in concrete is one which has the following surface texture 

a) smooth                                                 b) rough

c) glossy                                                    d) granular

59. The rock which is not calcareous, it

a) lime stone                                            b) macl 

c) chalk                                                     d) laterite

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

a) very fine sand                                    b) fine sand

c) medium sand                                     d) coarse sand

61. Pick up the incorrect statement from the following:

a) in properly graded aggregates, bulk density is more 

b) in single size aggregates, bulk density is least 

c) in single size aggregates, bulk density is maximum

d) none of the above

62. The bulk density of aggregates, depends upon

a) shape                                                            b) grading

c) compaction                                                  d) all of the above

63. The bulk density of aggregates, is generally expressed as 

a) tones/cubic metre                                    b) kg/cubic metre

c) kg/litre                                                        d) gm/ cubic cm

64. 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 straight horizontal line on the grading curve 

c) the omission of a certain size of aggregate is shown by straight horizontal line on the grading curve

d) all of the above

65. The type of aggregate of same nominal size, which contain less voids when compacted, are 

a) rounded spherical                                    b) irregular

c) flaky                                                            d) none of these

66. Inert material of a cement concrete mix, is 

a) water                                                         b) cement

c) aggregate                                                  d) none of the above

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

a) chemically inert                                       b) sufficiently strong

c) hard and durable                                     d) all of the above

68. An aggregate is known as cyclopean aggregate if its size is more than

a) 4.75 mm                                                  b) 30 mm

c) 60 mm                                                      d) 75 mm

69. Pick up the correct statement from the following: 

a) the maximum size of a coarse aggregate, is 75mm and minimum 4.75mm 

b) the maximum size of a fine aggregate, is 4.75mm and minimum 0.075mm 

c) the material having particles of size varying from 0.06mm to 0.002mm is known as slit

d) the material having particles of size less than 0.002mm, is known as clay

e) all of the above

70. If the aggregates completely pass through a sieve of size 75mm and are retained on a sieve of size 60mm, 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

71. In Q. be known as elongated aggregate if its length is not less than

a) 91.5mm                                                              b)101.5 mm

c)111.5mm                                                             d) 121.5 mm

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

a) 2/3 mean dimension                                      b) 3/4 mean dimension

c) 3/5 mean dimension                                      d) 5/8 mean dimension

73. A flaky aggregate is said to be elongated if its length is 

a) equal to the mean size

b) twice than the mean size 

c) thrice than the mean size

d) four times than the mean size

74. The minimum percentage of void in round aggregate is

a) 33 %                                                                    b) 53%

b) 43%                                                                    d) 63 %

75. The light weight aggregates may be obtained from 

a) sedimentary rocks                                         b) metamorphic rocks

c) igneous rocks                                                  d) volcanic source

76. To obtain a very high strength concrete, use very fine grained

a) granite                                                            b) magnetite

c) barite                                                              d) volcanic scoria

77. Pick up the correct statement from the following: 

a) sands obtained from pits, is washed to remove clay and silt 

b) sands obtained from flooded pits, need not be washed before use

c) sea shore sands contain chloride which cause efflorescence 

d) the chloride in sea shore sand and shingle may cause corrosion of reinforcement if the concrete is porous

e) all of the above

78. Pick up the correct statement from the following:

a) sand stones may be defined into calcareous, siliceous and ferruginous sand stones

b) concrete using sand stones, cracks due to excessive shrinkage 

c) very hard and close grained crystallized lime stones are suitable aggregates but provide low strength 

d) broken bricks produce a concrete having good fire resisting

qualities,

e) all of the above

79. The bulk density of an aggregate 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

80. Workability of concrete for a given water content is good if aggregates used are

a) rounded aggregate                               b) irregular aggregate

c) angular aggregate                                 d) flaky aggregate

81. The aggregate impact value of the aggregate used in

a) building concrete is less than 45 

b) road pavement concrete is less than 30

c) runway concrete is less than 30 

d) all of the above

82. The void ratio of

a) single size coarse aggregate is roughly 0.45

b) graded coarse aggregate is roughly 0.40 

c) fine aggregate is roughly 0.45

d) all of the above

83. The aggregate containing moisture in pores and having its

surface dry, is known as

a) moist aggregates   

b) very dry aggregates 

c) dry aggregates

d) saturated surface dry aggregates

84. Pick up the correct statement from the following:

a) bulking of sand is caused due to formation of a thin film of surface moisture

b) fine sand bulks more than coarse sand 

c) with 10% moisture content by weight, the bulking of sand is increased by 50%

d) the volume of fully saturated sand, is equal to the volume of dry and loose sand

e) all of the above

85. Log Angles machine is used to test the aggregate for 

a) crushing strength

b) impact value

c) abrasion resistance

d) water absorption

86. Pick up the correct statement from the following:

a) the bulk density of fine aggregate is usually about 10 percent more than that of coarse aggregate of similar composition 

b) the specific gravity of aggregate is important for the determination of the moisture content 

c) the absorption and porosity of an aggregate, influence the property of the concrete 

d) a highly absorptive aggregate reduces the workability of concrete considerably

e) all of the above

87. If 20 kg of a coarse aggregate is sieved through 80mm, 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, 5 kg, 6 kg, 4 kg, 3kg respectively, the fineness modulus of the aggregate, is 

a) 7.30

b) 7.35

c) 7.40

d) 7.45

88. The percentage of the aggregate of F.M. 2.6 to be combined with coarse aggregate of F.M. 6.8 for obtaining the aggregates

F.M 5.4 in 

a) 30%

b) 40%

c) 50%

d) 60%

89. IS sieve No. 10 mm and 4.75 mm are generally used for grading of 

a) coarse aggregate

b) fine aggregate

c) neither (a) nor (b) 

d) both (a) and (b) of above

90. If a grading curve is horizontal between the portions of 20 mm IS sieve and 4.75 mm IS sieve, graded aggregates do not contain.

a) 20 mm particles 

b) 10 mm particles

c) 4.75 mm particles

d) all of the above

91. For the construction of cement concrete dams, the maximum permissible size of the aggregates, is

a) 40 mm

b) 50 mm

c) 60 mm

d) 70 mm

92. For the construction of cement concrete floor, the maximum permissible size of the aggregates, is

a) 4 mm                                                   b) 6 mm 

c) 8 mm                                                   d) 10 mm

93.The most useless aggregates is one whose surface texture is

 a) smooth                                              b) granular 

c) glossy                                                  d) honey combed and porous

94. The concrete mainly consists of a) cement

c) aggregate

b) sand

d) all of the above

95. The impurity of mixing water which affects the setting time and strength of concrete, is

a) sodium sulphates

b) sodium chlorides 

c) sodium carbonates and bicarbonates

d) calcium chlorides

96. Water cement ratio is

a) volume of water to that of cement 

b) weight of water to that of cement

c) weight of concrete to that of water 

d) volume of concrete to that of water

e) both (a) and (b) of the above

97. Water cement ratio by weight is

a) higher as compared to that by volume.

b) lower as compared to volume

c) same as that by volume 

d) none of the above

98. Water cement ratio is generally expressed in volume of water required per

a) 10 kg

b) 20 kg 

c) 30 kg

d) 50 kg

99. Water cement ratio is normally used

a) 0.4-0.5 

b) 0.5-0.6

c) 0.6-0.65

d) 0.05-0.70

100. How much water read for M₂0 mix concrete of cement 50kg? 

a) 30 lit

b) 35 lit

c) 35 lit

d) 40 lit

101. The maximum water required for w/c ratio is

a) M₂5 

b) M20

c) Mis

d) MIO

102. Pick up the incorrect statement from the following:

a) a rich mix of concrete possesses lesser 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) if the water cement ratio is less that 0.45, the concrete is not workable and causes honey-combed structure 

d) good compaction by mechanical vibrations, increases the strength of concrete

103. 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 of the above

104. The minimum amount of water cement ratio for complete hydration of cement is

a) 0.40

b) 0.45

c) 0.50

d) 0.55

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

a) internal moisture conditions on hydration continue till complete strength is gained 

b) concrete specimens may be tested at any temperature

c) concrete specimens need be of same age

d) none of the above

106. Water required for M₂5 concrete per bag of cement, is

a) 7 kg

b) 14 kg

c) 21 kg

d) 35 kg

107. 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

108. Pick up the correct statement from the following: Internal friction between the ingredients of concrete, is decreasing by using

a) less water

b) fine aggregates

c) rich mix

d) more water and coarse aggregates

109. The strength and quality of concrete, depends upon

a) grading of the aggregates

b) surface area of the aggregates

c) shape of the aggregates

d) surface texture of the aggregates 

e) all of the above

110. After casting, an ordinary cement concrete

a) expands when dried 

b) shrinks when wet 

c) shrinks when dried

d) none of the above

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

a) 1%                                                              b) 2%

c) 3%                                                              d) 5%

112. Concrete containing

a) silícate aggregates, has higher co-efficient of expansion 

b) igneous aggregates, has intermediate co-efficient of expansion 

c) lime stones, has lowest co-efficient of expansion

d) all of the above

113. To hydrate 500 kg cement fully, weight of water needed, is

a) 100 kg                                                      b) 110 kg

c) 120 kg                                                       d) 130 kg

114. Gap grading is one 

a) in which one or more intermediate fractions are absent

b) in which the particles fall within a narrow limit of size fractions

c) in which combines different fractions of fine and coarse aggregate

d) in which all the particles are of uniform size

115. On a grading curve, gap grading is represented by a

a) a horizontal line 

b) a vertical line

c) NW inclined line

d) NE inclined line

116. Concrete mainly consist of

a) cement

b) aggregates

c) water

d) all of the above

117. The increased cohesiveness of concrete, makes it

a) less liable to segregation 

b) more liable to segregation

c) more liable to bleeding

d) more liable for surface scaling in frosty 

118. To produce impermeable concrete

a) thorough mixing of concrete is required 

b) proper compaction of concrete is required

c) proper curing of concrete is required 

d) properly graded and non-porous aggregates are required

e) all of the above

119. Pick up the correct statement from the following:

a) water cement paste hardens due to hydration 

b) during hardening cement binds the aggregates together 

c) cement provides strength, durability and water tightness to the concrete

d) all of the above

120. 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

121. Vicat’s apparatus is used for

a) fineness test

b) consistency test

c) compressive st. test

d) soundness test

122. 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

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

a) 20%                                                            b) 25%

c) 30%                                                            d) 35%

124. Pick up the incorrect statement from the following. For performing compressive strength test of cement 

a) cement and standard sand mortar are used in the ratio of 1:3

b) water is added at the rate of P/4 +3.0 percentage of water where P is the percentage of water for standard consistency 

c) a cube mould of 10cmx 10cm x 10cm is used

d) the prepared moulds are kept in an atmosphere of 50% relative humidity

125. Pick up the incorrect statement applicable to the field test of good cement

a) when one thrusts one’s hand into a bag of cement, one should feel warm 

b) the colour of the cement is bluish

c) a handful of cement thrown into a bucket of water should sink immediately

d) by rubbing the cement in between fingers, one should feel rough

e) all of the above

126. Pick up the correct statement from the following:

a) the concrete gains strength due to hydration of cement 

b) the concrete cured at a temperature below 23°C, gains strength up     to 28 days

c) the concrete does not set at freezing point

d) the strength of concrete increases with its age 

e) all of the above

127. At freezing point of water, concrete 

a) sets freely

b) sets slowly

c) sets rapidly 

d) does not set 

128. The datum temperature for maturity by Plowman, is

a) 23°C

b) 0°C 

c)-5.6°C

d)-11.7°C

129.I.S.I. has specified the full strength of concrete after

a) 7 days 

b) 14 days

c) 21 days

d) 28 days

130. The strength of concrete is directly proportional to

a) cement water ratio                        b) water cement ratio

c) sand cement ratio                          d) water aggregate ratio

131. The approximate ratio of strength of cement concrete at 3 months to that of 28 days of curing

a) 1.0                                                    b) 1.15

c) 1.20                                                  d) 1.30

132. The percentage of compressive strength of concrete at 7 days to that of 28 days  

a) 40%                                                  b) 65%

c) 100%                                                d) 115%

133. The approximate ratio of direct tensile strength to direct  compressive strength test of concrete

a) 0.65                                                  b) 0.40

c) 0.15                                                  d) 0.10

134. Gypsum is added for 

a) colour

b) strength

c) controlling setting time

d) none of these

135. High increase in temperature 

a) increases the strength of concrete

b) decreases the strength of concrete

c) has no effect on the strength of concrete 

d) none of these

136. Segregation is responsible for 

a) honey-combed concrete

b) porous layers in concrete

c) surface scaling in concrete

d) sand streaks in concrete 

e) all of the above

137. Separation of coarse aggregates from cement concrete during transportation, is known

a) bleeding                                                    b) creeping

c) segregation                                               d) shrinkage

138. Separation of water or water sand cement from a freshly mixed concrete, is known

a) bleeding

b) creeping

c) segregation 

d) shrinkage

139. The specific surface of cement is expressed in

a) mm²

b) mm/g

c) g/mm²

d) mm²/g mm

140. A setting of cement or concrete which occurs suddenly while being mixed and placed and prevents further working of the materials is called 

a) quick set 

b) flash set

c) initial setting 

d) knocking

141. Adding a thin layer of cement mortar to the surface of concrete

is known as

a) punning                                                     b) admixing

c) rodding                                                      d) rendering

142. The breaking up and remixing of concrete that has layers to set is called 

a) resetting

b) double setting

c) knocking 

d) time setting

143. A concrete mix that causes difficulty in obtaining a smooth or good contact with forms which may be due to excess of middle sized particles or a deficiency of lime materials is called

a) uneven mix

b) harsh mix

c) heterogeneous

d) none of the above

144. A watery scum that is formed on top of concrete due to excessive water or excessive use of trowel or float is called

a) laitance

b) flashing

c) punning

d) water facing

145. For protection from frost, concrete should be

a) dense

b) free from cracks

c)adhesion between mortar and aggregate should be perfect

d) all of the above

146. The lower water cement ratio in concrete, introduces 

a) smaller creep and shrinkage 

b) greater density and smaller permeability

c) improved frost resistance 

d) greater wear resistance and improved bond strength

e) all of the above

147. The entrained air in concrete 

a) increases workability

b) decrease workability

c) decrease resistance to weathering

d) increase strength

148. The concrete mix which causes difficulty in obtaining a smooth finish, is known to possess

a) segregation                                      b) internal friction

c) hardness                                           d) bleeding

149. The factor which affects workability, is

a) water content and its temperature

b) shape and size of the aggregates

c) grading and surface textures of the aggregates

d) air entraining agents 

e) all of the above

150. Pick up the correct statement from the following: 

a) an increase in water content must be accompanied by an increase in cement content

b) angular and rough aggregates reduce the workability of the concrete

c) large size aggregates increase the workability due to lesser surface area 

d) the slump of the concrete mix decreases due to an increase in temperature

e) all of the above