1. The fineness modulus of sand lies in the range:
a) 1-2
b) 0.5-1
c) 2-3
d) 2.5-3.5
Discussion
Explanation: Fineness modulus is an index number which represents average size of sand particles. It is calculated after conducting sieve analysis.
2. An ideal sand should comprise of which of the following grain types?
a) Cubical, fine
b) Angular, coarse
c) Round, coarse
d) Irregular, fine
Discussion
Explanation: For sand to be used in every type of construction, the grains must suit all requirements. Angular, coarse grained sand is the one suitable for all work.
3. Sand in mortar helps in adjusting the strength requirements:
a) True
b) False
Discussion
Explanation: The grade and amount of sane used in making mortar help in adjusting the strength parameter. It also helps in increasing resistance against crushing.
4. A sand is not said to be ideal if:
a) Chemically inert
b) Free from organic salts
c) Is soft
d) Contains silicon dioxide
Discussion
Explanation: An ideal sand should be hard and not soft. It will be difficult to work with if it is soft.
5. Sands should pass through:
a) BIS 480 sieve
b) BIS 8 sieve
c) BIS 5 sieve
d) BIS 6 sieve
Discussion
Explanation: The particle size of sand is between 4.75mm and 75 microns. BIS 480 sieve represents 4.75mm sieve opening.
6. Bulking of sand increase the strength of the mortar
a) True
b) False
Discussion
Explanation: Bulking increases volume of mortar and not the strength. In fact, it decreases the strength, leading to future cracks in the structure.
7. The solution used to test impurities in the sand in field is:
a) Sodium sulphate
b) Sodium hydroxide
c) Sodium nitrate
d) Sodium chloride
Discussion
Explanation: A small amount of sand is added to a solution of sodium hydroxide and stirred. If colour changes to brown, presence of impurity is detected.
8. What is the maximum percentage of silt allowed in sand to be used in concrete?
a) 5%
b) 10%
c) 8%
d) 2%
Discussion
Explanation: If more silt content is present, it will lead to the improper measurement of volume or weight. It should be washed off to bring it to the allowable limit.
9. Which one of the below cannot to be used as a substitute of sand?
a) Surkhi
b) Quarry dust
c) Glass
d) M-sand
Discussion
Explanation: Surkhi is pieces of burned clay, M-sand is manufactured sand, glass can be powdered and these form excellent substitutes for sand. Quarry dust has flaky grains and is not recommended to use in concrete or masonry works, though it can be used for low strength works.
10. The density of wet sand is:
a) 1922 kg/m3
b) 1682 kg/m3
c) 1281 kg/m3
d) 1522 kg/m3
Discussion
Explanation: 1682 kg/m3 is density of rammed sand, 1281 kg/m3 is density of dry sand and 1522 kg/m3 is of silica sand.