81. Which type of aggregates give maximum strength to concrete?
- Flaky aggregates
- Angular aggregates
- Rounded aggregates
- Mixed aggregates
82. What is the most desirable form of coarse aggregates for developing a Mix Design in Laboratory?
- bone dry aggregates
- wet aggregates
- saturated surface dry aggregates
- saturated aggregates
83. In which of the following, the concrete is dropped from a height to measure its workability
- Vee Bee test
- Slump Test
- Compaction factor test
- Flow test
84. What is the equivalent strength of concrete for the Mix Ratio of 1:2:4?
- M10
- M15
- M20
- M25
85. Use of Sea water in making of concrete results into
- Loss of strength
- Corrosion of reinforcement
- Dampness
- Efflorescence
Which of the following is a correct combination?
- i and ii
- iii and iv
- i, iii and iv
- i, ii, iii and iv
86. Which of following is not a function of sand in mortar?
- Providing strength
- Reducing the consumption of cement
- Reducing shrinkage
- Reducing the setting time
87. Why is super plasticizer added to concrete?
- To reduce the quantity of mixing water
- To increase workability
- To reduce the quantity of cement
- To increase early age strength
- i and iv
- i, ii and iv
- iii and iv
- i, ii, iii and iv
88. An aggregate is termed as flaky if
- its least lateral dimension is less than 0.6 times its mean dimension
- its length is 1.8 times more than its mean dimension
- its least lateral dimension is less than 1.8 times its mean dimension
- its length is 0.6 times more than its mean dimension
89. The size of aggregate, particle shape, colour, surface texture, all of which have influence on the durability of concrete should conform to
- IS 383-1970
- IS 1489-1976
- IS 12269-1987
- IS 456-2000
90. The approximate ratio between the strength of cement concrete at 7 days and at 28 days is
- 1/3
- 1/2
- 2/3
- 3/4