Gypsum is added in the manufacture of Portland cement

A good quality cement should have higher percentage of

The process of mixing clay, water and other ingredients to make bricks, is known as

The lime which consists almost entirely of calcium oxide, is called

A first class brick should not absorb water more than

Efflorescence is caused if

The rate of hydration and hydrolysis of cement depends upon its

Seasoning of tunber

Gneiss is chemically classified as