Effect of fineness and dosage of aluminium powder on the properties of moist-cured aerated concrete

• Behaviour of different fineness of aluminium powder were studied.
• Assessing the rate of aeration with respect to change in fresh density.
• Variation in dosage of aluminium powder and water–cement/solids ratio affects the fresh and hardened properties.

The influence of fineness of aluminium powder through an evaluation of variation in the workability of the mix, rate of aeration and fresh density with time, dry density, compressive strength and water absorption of aerated cement paste and mortar were studied. Flow table test clearly distinguishes variation in initial workability of the mixes for the variations in water–cement ratio, whereas the Marsh cone test is suitable for reflecting the reduction in workability of the mix with time caused by aeration. The dosage of aluminium powder required to achieve a desired density reduces with an increase in its fineness. Inconsistent with the dosage of aluminium powder required, for a given dry density or compressive strength of aerated cement paste or mortar, the water absorption increases with fineness of aluminium powder. For a given fineness of aluminium powder, appropriate dosage and water–cement ratio required has to be identified based on the desired density and strength, or strength to density ratio.