Day 31-Oct 20-Btech-worksheet-Mortar

Bulking of sand is maximum when —

• Sand is completely dry

• Moisture content is above 12%

• Moisture is around 5–8%

• Immersed fully in water

Surkhi mortar is unsuitable for plastering mainly because —

• It contains calcareous impurities

• It disintegrates after exposure to weather

• It increases setting too much

• It causes excessive shrinkage

In gauged mortar, lime serves primarily to —

• Increase density

• Improve plasticity

• Reduce water retention

• Increase shrinkage

The manufacturing of lime mortar in small scale is carried out by —

• Pug milling

• Kneading

• Pressing

• None

Fine sand exhibits more bulking compared to coarse sand.

• True

• False

Fat lime mortar is suitable for use in continuously water-logged foundations.

• True

• False

Assertion (A): Surkhi mortar is commonly used in foundation work. Reason (R): Surkhi increases resistance to disintegration under sub-soil moisture conditions.

• Both A and R are true and R is correct explanation

• Both A and R are true but R is NOT the correct explanation

• A true, R false

• A false, R true

The fineness modulus of medium sand should lie between (a)   .

The increase in volume of sand due to surface moisture is called (a)   .

Cement mortar for DPC is generally used in the proportion (a)   .