Concrete Technology and Design

101. How long will it take for the concrete to achieve 100% of its strength?

1. 7 days
2. 14 days
3. 21 days
4. 28 days

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

1. Tricalcium silicate and dicalcium silicate
2. Dicalcium silicate and tricalcium aluminate
3. Tricalcium aluminate and tricalcium alumino ferrite
4. All the above

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103. I.S. Sieve Nos. 10 mm and 4.75 mm are generally used for grading of

1. Coarse aggregates
2. Fine aggregates
3. Neither (a) nor (b)
4. Both (a) and (b)

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

1. 20 %
2. 25 %
3. 30 %
4. 35 %

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105. If 20 kg of coarse aggregate is sieved through 80 mm, 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, 8 kg, 6 kg, 4 kg respectively, the fineness modulus of the aggregate, is

1. 7.3
2. 7.35
3. 7.4
4. 7.45

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106. 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

1. 8 kg
2. 10 kg
3. 12 kg
4. 14 kg

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

1. Increasing the depth of beam
2. Using thinner bars but more in number
3. Using thicker bars but less in number
4. Providing vertical stirrups

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108. If a grading curve is horizontal between the portions of 20 mm I.S. Sieve and 4.75 mm I.S. Sieve, the graded aggregates do not contain

1. 20 mm particles
2. 10 mm particles
3. 4.75 mm particles
4. All the above

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109. If aggregates completely pass through a sieve of size 75 mm and are retained on a sieve of size 60 mm, the particular aggregate will be flaky if its minimum dimension is less than

1. 20.5 mm
2. 30.5 mm
3. 40.5 mm
4. 50.5 mm

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

1. Very fine sand
2. Fine sand
3. Medium sand
4. Coarse sand

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