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

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

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Building Materials
The thermosetting plastic

Chars at 343°C
Becomes rigid when moulded at suitable pressure and temperature
All listed here
At 127°C to 177°C permanently set and further application of heat does not soften it

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