Concrete Technology and Design

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

1. 2/3 mean dimension
2. 3/4 mean dimension
3. 3/5 mean dimension
4. 5/8 mean dimension

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32. An aggregate which passes through 25 mm I.S. sieve and is retained on 20 mm sieve, is said to be flaky if its least dimension is less than

1. 22.5 mm
2. 18.5 mm
3. 16.5 mm
4. 13.5 mm

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33. An excess of flaky particles in concrete aggregates

1. Decreases the workability
2. Increases the quantity of water and sand
3. More than 15% are not desirable
4. All the above

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34. An ideal ware house, is provided

1. Water proof masonry walls
2. Water proof roof
3. Few windows which remain generally closed
4. All the above

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35. An ordinary Portland cement when tested for its fineness, should not leave any residue on I.S. sieve No. 9, more than

1. 5 %
2. 10 %
3. 15 %
4. 20 %

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36. Approximate value of shrinkage strain in concrete, is

1. 0.003
2. 0.0003
3. 0.00003
4. 0.03

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37. As compared to ordinary Portland cement, high alumina cement has

1. Higher initial setting time but lower final setting time
2. Lower initial setting time but higher final setting time
3. Higher initial and final setting times
4. Lower initial and final setting times

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38. As compared to ordinary Portland cement, use of pozzolana cement

1. Reduces workability
2. Increases bleeding
3. Increases shrinkage
4. Increases strength

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39. Assertion A : The load factor for live load is greater than that for dead load. Reason R : The live loads are more uncertain than dead loads. Select your answer based on the coding system given below:

1. Both A and R is true and R is the correct explanation of A
2. Both A and R is true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true

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40. Batching error means inaccuracy in the quantity of

1. Aggregates
2. Cement
3. Water
4. All the above

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