Behaviour and assessment of foamed concrete for fill and highway applications

Foamed concrete is used in a wide range of construction applications, e.g. void filling, trench reinstatement, bridge abutments and arch infills, road sub-bases, soil stabilisation, thermal and acoustic insulation, floor and roof screeds. However, despite the attractive material attributes (flowability, self-compacting and self-levelling nature, low dimensional change and ultra-low density and excellent thermal insulation properties), only limited data exists on foamed concrete performance and guidance on its use and quality control is scarce. This keynote paper reviews the history of use of foamed concrete, its typical construction applications and some projects carried out worldwide. The current state of knowledge is assessed and focuses on the constituent materials used in its production, mix proportioning methods and foamed concrete properties. Two example applications of foamed concrete are reported using a case study, where the production, placement and performance of two foamed concrete mixes in trench fill housing foundations and ground-supported slab was examined. Finally, the future potential for the material is considered.