71.  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 the above

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72. Ilardening 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 these

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73.  ISI has specified the full strength of concrete after
A. 7 days
B. 14 days
C. 21 days
D. 28 days

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74. High 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

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75.  Placing of concrete should preferably be done at temperature of
A. 0?C
B. 10?C
C. 20?C
D. 27 ? 2?C

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76. Water required per bag of cement, is
A. 7 kg
B. 14 kg
C. 21 kg
D. 35 kg

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77.  CRR1 charts are used to obtain a relatioship between strength of concrete and
A. water cement ratio
B. workability
C. grading of aggregate
D. fineness modulus

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