Foamed concrete, also known as foam concrete or lightweight concrete, is foamed through concrete foaming system. The foaming agent is fully foamed by mechanical means, and the foam is mixed with cement slurry evenly. Then, a new lightweight thermal insulation material, which contains a large number of closed pores, has been formed through the pumping system of the foaming machine and the molding of the cast-in-place or mould. Foamed concrete is a kind of polymer with double continuous structure, which is composed of foaming agent, cement, fly ash, stone powder and other organic cementitious materials, and contains uniform air holes; foam concrete is used for roof insulation and slope making, ground insulation cushion, foundation pit filling of upper turnover beam, wall pouring and other energy-saving materials.
Due to the large number of closed pores in foamed concrete, it has the following good physical and mechanical properties.
1. Light weight
The density of foamed concrete is small, and its density is generally 300-1800kg/m3. The density of commonly used foamed concrete is 300-1200 kg/m3. In recent years, ultra light foam concrete with density of 160 kg/m3 has been applied in construction projects. Because of the low density of foam concrete, the building material can be reduced by about 25% by using the material in the building's internal and external walls, floors, floors and columns. For structural members, if foamed concrete is used instead of ordinary concrete, the bearing capacity of members can be improved.
2. Good thermal insulation performance
Because there are a large number of small closed pores in foamed concrete, it has good thermal performance, that is, good thermal insulation performance. The thermal conductivity of foamed concrete is 0.08-0.3w / (m · K), and the thermal resistance is about 10-20 times of that of ordinary concrete.
3. Good sound insulation and fire resistance
Foamed concrete is a porous material, so it is also a good sound insulation material. It can be used as a sound insulation layer in the floors of buildings, sound insulation boards of expressways and the top floor of underground buildings. Foamed concrete is inorganic material. It will not burn, so it has good fire resistance. It can improve the fire resistance of buildings.
4. Low elasticity and good shock absorption
The porosity of foamed concrete makes it have low elastic modulus, so it has good absorption and dispersion effect on impact load.
5. Strong waterproof performance
The low water absorption, relatively independent closed bubbles and good integrity make the cast-in-place foamed concrete have certain waterproof performance.
6. Good durability
It has the same service life as the main project.
7. Convenient production and processing
Foamed concrete can not only be produced into a variety of products in the factory, but also can be directly cast-in-place into roof, floor and wall.
8. Good environmental performance
The raw materials of foamed concrete are cement and foaming agent. The foaming agent is neutral and does not contain harmful substances such as benzene and formaldehyde, so as to avoid environmental pollution and fire hazards.