Aerated concrete is produced by the incorporation of a gas or air in a base mortar mix, it is categorised in two groups.
Gas formed within the mass of the fresh mortar by means of a chemical reaction. These units are factory manufactured in steel moulds and autoclaved. They can be reinforced and have high thermal insulation properties. Block types include Thermalite and Celcon.
Foamed concrete is where air is introduced to the base mix by an addition of a preformed foam. Excellent as a trench fill material, it is generally unreinforced and air cured.