Cellular Lightweight Concrete is an increasingly popular material for diverse construction applications, from thermal and acoustic insulation and building elements to mine reinstatement and ground stabilisation. Much of the technical development of the material has taken place in many research centers and universities has led to the successful development structural grade foamed concrete, foamed concrete for use in thermally insulating housing foundations and ground slabs, nuclear decommissioning and the specification for highway applications.
   It is a blend of pre-formed foam, Portland cement, filler (either sand or waste PFA and so on), high range water reducing and set controlling admixtures and water. Foamed concrete can be produced to have any required compressive strength from 1 to 30 N/mm2 at densities from 300 to 1,800 kg/m3. Around 20 to 70% of its volume is made up of closed cell bubbles arising from the pre-formed foam, which provides the insulation properties of the material. Recently completed projects have also shown that foamed concrete is an ideal material through which, the consumption of primary aggregates can be reduced. This is due to the high volume of air and that coarse aggregates are not required in the foamed concrete matrix. It has also been shown that foamed concrete can utilise a wide range of fine recycled and secondary aggregates (RSA), which are otherwise difficult to use in any other application, as partial or full replacement for primary sand, and, therefore, are largely going to landfill.