Autoclaved Aerated Concrete (AAC) is a precast building material made from natural raw materials. It is also known as Autoclaved Cellular Concrete (ACC). This solid concrete block is economical, energy-efficient and environment friendly. It is fire and termite resistant. In addition, it also provides sound and thermal insulation.
A combination of silica sand or recycled fly ash, lime, water and aluminum paste or powder is mixed with Portland cement. This mixture is poured into a mold. The aluminum and the concrete give rise to microscopic hydrogen bubbles. These bubbles help in expanding the concrete to around five times its original size. After the hydrogen evaporates the aerated concrete is cut into the desired size and steamed in a pressurized chamber known as an autoclave.