Bricks MCQ with answer and solution

Concept

Effect of excess silica in brick clay

Formula

NONE

Step-by-step solution

1. Silica is a primary constituent of good brick earth, providing strength and durability. 2. Excess silica destroys cohesion between soil particles and causes the brick to become brittle and weak upon burning. 3. It also causes bricks to crack and warp during drying if present in incorrect proportions without proper binder. Answer: A

Explanation

Silica is a primary constituent of brick earth that prevents shrinkage, warping, and cracking during drying and burning. However, an excessive proportion of silica destroys cohesion between clay particles and renders the brick brittle upon firing. Consequently, the brick loses its structural toughness and breaks easily under load.

Why the other options are wrong

B) Excess lime or alkalis cause bricks to melt and lose shape on burning. C) Excess alumina causes bricks to shrink and crack on drying. D) Excess alumina or uneven drying causes bricks to warp.

Shortcut

Excess Silica makes bricks brittle and weak on burning; excess Alumina causes shrinkage/warping.

Common mistake

Confusing the effect of excess silica, which causes brittleness, with excess alumina, which causes cracking and warping.