Enamel paint is made by adding

The specific surface (in cm2/g) of a good Portland cement should not be less than

Sandstone consists of

The silicious sandstone which has been subjected to metamorphic action, is called

The central part of a tree is called

Excess of silica in the clay

The dolomite bricks are

Efflorescence is caused if

The rate of hydration and hydrolysis of cement depends upon its