169.  An excess of flaky particles in concrete aggregates
A. decreases the workability
B. increases the quantity of water and sand
C. affects the durability of concrete
D. all the above

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170.  A flaky aggregate is said to be elongated if its length is
A. equal to the mean size
B. twice the mean size
C. thrice the mean size
D. four times the mean size

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171.  An aggregate is said to be flaky if its least dimension is less than
A. 1/5th of mean dimension
B. 2/5th of mean dimension
C. 3/5th of mean dimension
D. 4/5th of mean dimension

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172.  For given water content, workability decreases if the concrete aggregates contain an excess of
A. thin particles
B. flat particles
C. elongated particles
D. all the above

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173.  Grading of sand causes great variation in
A. workability of concrete
B. strength of concrete
C. durability of concrete
D. all the above

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174.  On a grading curve, the gap grading is represented' by
A. a horizontal line
B. a vertical line
C. NW inclined line
D. NE inclined line

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175.  IS Sieve Nos 10 mm and 475 mm are geneally used for grading of
A. coarse aggregates
B. fine aggregates
C. neither A nor B
D. both A and B

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