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Cellular or aerated concrete


     Cellular or aerated concrete :- It is prepared by mixing aluminium in the cement concrete. It is light in weight and spongy in structure. It is used for roof slab and precast unit in partition for heat and sound insulation. It also called air-entrained concrete.

Ø Advantages:-

a)    Workability of concrete increases.
b)    Use of air entraining agent reduces the effect of freezing and thawing.
c)    Bleeding, segregation and laitance in concrete reduces.
d)    Entrained air improves the sulphate resisting capacity of concrete.
e)    Reduces the possibility of shrinkage and crack formation in the concrete surface.

Ø Disadvantages:-

a)    The strength of concrete decreases.
b)    The use of air entraining agent increases the porosity of concrete thereby reducing the unit weight.
c)    Air-entrainment in concrete must not be done if the site control is not good. This is due to the fact that the air entrained in a concrete varies with the change in sand grading, errors in proportioning and workability of the mix and temperatures.

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