Lightweight concrete, also known as foamed cement, foam concrete, etc., is a new energy-saving building material with advantages of waste, environmental protection, energy saving, low-cost and non-combustibility. Foamed concrete is a kind of concrete product that contains a lot of small closed stomata and has considerable strength through the rational maintenance and molding of concrete or air, such as air or nitrogen, carbon dioxide gas and oxygen, through chemical or physical means. Foamed concrete is usually made by foaming the foam solution with mechanical method, adding foam into the slurry containing siliceous materials, calcareous materials, water and various admixtures. It is a porous material made by mixing stirring, pouring and curing.
The density of foam concrete is small, and the density grade of commonly used foamed concrete is 300 - 1200kg/m3, which is equivalent to the 1/5 - 1/10 of regular concrete. And the compressive strength is greater than 0.25Mpa, the foamed concrete products with different strength can be produced according to the design requirements of buildings. Generally, the weight of buildings can be reduced by about 25%, and some of them can reach 30% - 40% of the total weight of structures when this material is used in building structures such as internal and external walls, layers, exposed surfaces and columns, In recent years, ultra-light foam concrete with a density of 160 kg/m3 has also been applied in construction projects. Because the density of foam concrete is low, so it could reduce the weight of buildings significantly, improve the bearing capacity of buildings, and enhance the seismic capacity of buildings. Therefore, the use of foam concrete in construction projects has significant economic benefits.
The thermal performance is great because the foam concrete contains a lot of closed small pores. The foam concrete with a density range of 300 to 1200kg/m3 has a thermal conductivity of 0.06 to 0.3W (M.K). Foam concrete is used as the building wall and roof material. It has good thermal insulation and energy saving effect.
Foamed concrete is a porous material with attraction power of 0.09-0.19%. It has good soundproofing properties. It can be used as a sound insulation layer in building floors, baffle board and underground buildings. Unlike traditional sound insulation materials, Foam concrete is inorganic and non-flammable, thus providing good fire resistance and improving the safety and fire performance of buildings.
The porosity of foam concrete has a low elastic modulus, so that it has good absorption and dispersion effect on impact load. Meanwhile, the characteristics of foamed concrete is lightweight and high-strength, it can reduce the load of buildings effectively in the range of 20%-40%. The smaller the building load, the more resilient it is to earthquakes.
On-site pouring and mechanized construction make the speed of construction 1/3 faster than polystyrene foam board.