Aerated Autoclaved Concrete (AAC)

Lime plays a crucial role in the production of aerated autoclaved concrete (AAC). AAC is a lightweight, precast, foam concrete building material that provides structure, insulation, and fire and mold resistance. The primary ingredients in AAC include sand, cement, lime, gypsum, and water, along with an expansion agent, typically aluminum powder.

In the production of aerated autoclaved concrete (AAC), two primary types of lime are used: quicklime (calcium oxide, CaO) and hydrated lime (calcium hydroxide, Ca(OH)₂). Quicklime, produced by heating limestone, is highly reactive and enhances the chemical reactions during autoclaving but requires careful handling. Hydrated lime, formed by adding water to quicklime, is safer and easier to handle. The choice between quicklime and hydrated lime depends on factors like reactivity, handling safety, production efficiency, cost, and local availability. Both types of lime contribute to forming the calcium silicate hydrates (CSH) that give AAC its strength and stability.