AAC Resources

The Basics: Autoclaved Aerated Concrete, also known as AAC, is a lightweight concrete product manufactured by mixing cementitious materials, cement and/or pulverized fuel ash (PFA), lime, sand, water and aluminium oxide powder. The final process involves autoclaving for approximately 10 hours at high temperature and pressure. Hydrogen gas is used to create air bubbles in the mix.AAC is comprised of 60% to 85% of air by volume (70-85% for low density AAC). The solid material part is a crystalline binder, which is called Tobermorite by mineralogists. Besides the binding phase tobermorite, grains of Quartz and some other minerals are found in minor amounts. The chemical composition of tobermorite comprises of silicium dioxide, calcium oxide and water. It is tobermorite, which provides the high compressive strength of AAC in spite of the high proportion of pores in this construction material. Therefore low density is sufficiently strong for the construction of dwellings in spite of its considerably high air content. AAC is generally rated at 8 MPa, with up to 80% of its volume made up of air. Its lightweight nature, which is 20% lighter than standard concrete, makes it easier to work with. AAC materials can be sanded and cut to size using standard power tools and have superior thermal properties to standard concrete. AAC comes in a variety of product types, including blocks and panels. AAC blocks are typically used for domestic wall construction and are available as a 600 mm wide and 200 mm high block in thicknesses ranging from 50 to 300 mm. Blocks can be used for loadbearing walls up to three storeys. Panels are often used for both wall and floor construction in residential and commercial applications. They are 600 mm wide, 75 mm thick and come in lengths ranging from 1800 to 4800 mm..