Civil engineer objective questions – Concrete Technology (Section-3)

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

a) M25

b) M20

c) M15

d) M10

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

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