Foam Concrete

Foam concrete is a cement paste or mortar in which air-voids are entrapped by the foaming agent and has excellent thermal and insulation properties with a very low density. It can be used as non-structural or structural void filler in buildings and can reduce construction costs. It also resists cracking and shrinkage much better than standard concrete. It is often used as a precast concrete block and can be poured into walls, floors and roofs to produce an insulating layer. It can also be used for filling ducts, basements, cellars, underground pipes and culverts.

Foamed concrete is made by mixing the foaming agent with sand and water. The agent can either be protein-based or synthetic. The synthetic foam agents are easier to handle and require less energy. They can be stored for a longer time and are cheaper than the protein-based foams. The protein-based foams create a more stable and dense bubble structure.

The main disadvantage of foam concrete is that it has a lower density than traditional concrete and therefore has less strength and durability. It can however be used as a building material because it is very light and is able to resist earthquakes and temperature changes.

The base mix for foam concrete consists of sand, cement and water. It has to have a high cement content of at least 350 kg/m3. In addition, pulverised fuel ash and ground granulated blast-furnace slag can be added in varying quantities depending on their availability and reaction level with the foaming agent. Aerogel is also incorporated into the mixture to decrease the density of the mixture while enhancing its performance.