Building Materials Questions & Answers - Page 9

41.

In cement, the compound quickest to react with water is

A.

Tricalcium aluminate

B.

Tetra-calcium alumino-ferrite

C.

Tricalcium silicate

D.

Dicalcium silicate

Correct answer is A

No explanation has been provided for this answer.

42.

In the method of condensation polymerization,

A.

low-molecular substances are removed from the high molecular substance

B.

the reaction proceeds with an evolution of ammonia

C.

the reaction proceeds with an evolution of hydrogen chloride

D.

all the above

Correct answer is D

No explanation has been provided for this answer.

43.

Bitumen felt

A.

is used as water proofing material

B.

is used as damp proofing material

C.

is made from bitumen and hessian fibres

D.

all the above

Correct answer is D

Bitumen felt is a type of building material that is used for water proofing and damp proofing. It is made from bitumen, a sticky, black, semi-solid form of petroleum, and hessian fibres, which are made from jute or other natural fibres. Bitumen felt is typically used to protect roofs, walls, and other structures from water damage by providing a barrier that prevents water from penetrating the surface. It is also used to prevent dampness and condensation from forming inside buildings by allowing moisture to escape from the structure. Bitumen felt is typically applied in thin layers using a hot asphalt or tar application process, which helps it bond to the surface and form a watertight seal.

44.

Elastomers can extend upto

A.

five times their original dimensions

B.

seven times their original dimensions

C.

ten times their original dimensions

D.

three times their original dimensions

Correct answer is C

Elastomers are a type of polymer that are known for their ability to stretch and deform under stress and then return to their original shape when the stress is removed. This property, called elasticity, is what gives elastomers their name. Elastomers can stretch to great lengths, often up to ten times their original dimensions, without breaking or permanently deforming. This makes them useful in a variety of applications, such as seals, gaskets, and shock absorbers, where a flexible and durable material is needed.

45.

Ultimate strength of cement is provided by

A.

Tricalcium silicate

B.

Di-calcium silicate

C.

Tri-calcium aluminate

D.

Tetra calcium alumino ferrite

Correct answer is B

Dicalcium Silicate (C2S): This compound will undergo reaction slowly. It is responsible for the ultimate strength of concrete. This is also called as Belite. The heat of hydration is 260 J/Cal. Its proportion is 25 - 40%.