Air contents in concrete

As per IS 456 air contents in concrete should not exceed 5 +-1% for 20 mm aggregate and 4+-1% for 40 mm aggregate concrete. It can be checked theoretically by dividing density of concrete from batching plant to the density as per mix design multiplying by 100. or it can be checked by air pressure method. the decrees in volume in container give the %age of air by giving pressure.

However concrete being impermeable there should be 0% air voids ar as taken in mix design.

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