page_title: Foam concrete
section_title: History
hierarchical_section_title: Foam concrete / History
caption_attribution_description: The rebuilt (1930) Smithy bridge, looking north. The bridge was infilled with foamed concrete to make it stronger, and to preserve the structure and path of the canal should it be restored here.It was also unfilled due to intravenous drug use and needles being left.
context_page_description: Foam concrete, also known as Lightweight Cellular Concrete, Low Density Cellular Concrete, and other terms is defined as a cement-based slurry, with a minimum of 20% foam entrained into the plastic mortar. As mostly no coarse aggregate is used for production of foam concrete the correct term would be called mortar instead of concrete; it may be called "foamed cement" as well. The density of foam concrete usually varies from 400 kg/m³ to 1600 kg/m³. The density is normally controlled by substituting fully or part of the fine aggregate with foam.
context_section_description: The history of foam concrete dates back to the early 1920s and the production of autoclaved aerated concrete, which was used mainly as insulation. A detailed study concerning the composition, physical properties and production of foamed concrete was first carried out in the 1950s and 60s. Following this research, new admixtures were developed in the late 1970s and early 80s, which led to the commercial use of foamed concrete in construction projects. Initially, it was used in the Netherlands for filling voids and for ground stabilisation. Further research carried out in the Netherlands helped bring about the more widespread use of foam concrete as a building material. More recently, foam concrete is being made with a continuous foam generator. The foam is produced by agitating a foaming agent with compressed air to make "aircrete" or "foamcrete". This material is fireproof, insect proof, and waterproof. It offers significant thermal and acoustic insulation and can be cut, carved, drilled and shaped with wood-working tools. This construction material can be used to make foundations, subfloors, building blocks, walls, domes, or even arches that can be reinforced with a construction fabric.
caption: The 1930s-era Smithy bridge used foamed concrete for infilling.
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