Composition of Good Brick Earth and its Properties that affect the Bricks

Composition of Good Brick Earth and its Properties thats effect on bricks

Composition of good  Brick Earth

composition	in percent	properties contribution	property on excess
Silica	50-60%	retaining the shape of brick prevent cracking, shrinkage, warping of raw brick	destroy the cohession between particles and make brick brittle
Alumina	20-30%	plasticity to brick	weak and warp on drying of brick
Lime	10%	prevent shrinkage on drying	melt and brick loose  its shape
Iron Oxide	<7%	gives red color helps lime to fuse with sand	dark blue color
manganese oxide	<1%	yellow tint color decrease shrinkage	decay of brick
sulphur oxide carbon dioxide	very small		spongy, swollen structure in the brick decolored by white  blotches
water	very small
Note	good clay for making the brick is weathered clay.
Alkalies		very small	melt and loose their shape
Organic matter		none	after burning leaving pores and make brick porous
Pebbles, Gravels, Grits		lesser	weak and porous not give uniformity  during mixture