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Building Materials - Engineering

Q1:

For making fly-ash building bricks, the following mix of fly-ash, sand and lime, is

A 80 : 13 : 7

B 70 : 20 : 10

C 60 : 35 : 5

D none of these.

ANS:A - 80 : 13 : 7

The raw materials for Fly Ash Bricks are:

Material ------ Mass
Fly ash ------ 60%
Sand/Stone dust ------ 30%
Ordinary Portland Cement/(Lime+Gypsum) ------10%
Total formula of material ------100%

The strength of fly ash brick manufactured with the above compositions is normally of the order of 7.5 N/mm2 to 10 N/mm2.

Fly ash bricks are lighter and stronger than clay bricks.