Autoclaved aerated concrete

Autoclaved aerated concrete (AAC) also referred to as autoclaved cellular concrete (ACC) or simply autoclaved concrete is a lightweight, prefabricated concrete building material. Developed in the mid-1920s, it is an alternative to traditional concrete blocks and clay bricks. AAC products are factory-prefabricated, in contrast to cellular concrete, which is typically mixed and poured on-site.

AAC is a combination of quartz sand, gypsum, lime, Portland cement, water, fly ash, and aluminium powder. After the aerated mixture is partially cured in a mould, the material is further cured under heat and pressure in an autoclave. AAC can be made into blocks, wall panels, floor and roof panels, cladding (façade) panels, and lintels.

AAC materials are typically cut using standard power tools equipped with carbon steel cutters. AAC products may be used in various construction projects similarly to cellular concrete. For any exterior use, they may require an applied finish to guard against weathering. A polymer-modified stucco or plaster compound can be used for this purpose, as well as a covering of siding materials such as natural or manufactured stone, veneer brick, metal, or vinyl siding.