Air-entrained concrete

Autoclaved aerated concrete (AAC), also known as autoclaved cellular concrete or autoclaved concrete, is a lightweight, precast building material that is used as an alternative to traditional concrete blocks and clay bricks. It was developed in the mid-1920s by Johan Axel Eriksson. Unlike cellular concrete, which is typically mixed and poured on-site, AAC products are manufactured in a factory under controlled conditions. The composition of AAC includes a mixture of quartz sand, gypsum, lime, Portland cement, water, fly ash and aluminium powder. Following partial curing in a mould, the AAC mixture undergoes additional curing under heat and pressure in an autoclave. AAC is used in various forms including blocks, wall panels and lintels. Shaping and cutting AAC can be done with a handsaw. When used externally, AAC products need a protective finish to prevent water absorption and damage.