Aerated concrete, also called cellular concrete or autoclaved aerated concrete (AAC), is lightweight concrete full of tiny air cells, which makes it light, insulating and easy to work. The material is widely used for interior walls and is popular with DIYers because it can be cut and glued so easily.
How aerated concrete is made
Aerated concrete is made from a mixture of fine sand or fly ash, lime, cement and water. A small amount of aluminium powder is added as a gas-forming agent. The aluminium reacts with the lime to produce hydrogen gas, which makes the mixture rise the way yeast makes dough rise. In the process, millions of small, evenly distributed air cells are formed.
After rising, the mass is cut to size and cured in an autoclave: a large pressure vessel in which the material hardens under high steam pressure. Thanks to this treatment, aerated concrete gains its stable, firm structure. A well-known brand is Ytong.
Properties
- Light in weight — thanks to the air cells, the material weighs far less than ordinary concrete
- Good insulation — the air in the cells slows heat and sound transfer
- Easy to work — sawing, drilling and routing can be done with hand tools
- Fire resistant — aerated concrete is non-combustible and heat resistant
Application
Aerated concrete is supplied as glue blocks or large panels and is used for both non-load-bearing and load-bearing interior walls. The blocks are stacked with a thin glue mortar, producing smooth, accurate walls. The material is ideal for dividing up rooms, building partition walls and constructing storage rooms or extensions. Because it is so light and easy to saw, aerated concrete is a favourite material for home builders.
Related terms
- Concrete
- Bricklaying
- Insulation
- Foundation
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