Building Materials
Excess of alumina in brick earth makes the brick

To crack and warp on drying
To lose cohesion
Impermeable
Brittle and weak

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Building Materials
When a brick is immersed in water for 24 hours and then dried, if

50 percent surface is covered with grey or white deposits, the brick has serious efflorescence
All listed here
No grey or white deposits appear on the surface, the brick is free from soluble salts
10 percent surface is covered with grey or white deposits, the brick has slight efflorescence

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