Foam concrete is made of inorganic materials. It has simple process, low cost and good thermal insulation performance. It is often used for building thermal insulation. It is an ideal substitute for thermal insulation materials in agricultural production system and becomes a major turning point from thermal insulation to inorganic thermal insulation in agricultural production system. At present, the application status of foam concrete in China is not ideal, and its development is restricted by factors such as single production variety and non-standard production. This paper summarizes the characteristics and application status of foam concrete, and puts forward several suggestions.
In recent years benzene The problems such as fire hazard, falling hazard, durability, and huge amount of garbage generated after the service period of the building thermal insulation system with board as the main material are exposed one by one, and the industry calls for the elimination of foamed polystyrene and foam polyurethane The sound wave of thermal insulation materials for agricultural production systems is increasing day by day. It was found in the study of new thermal insulation materials that foaming agent Foam concrete, a microporous lightweight material formed by mechanical foaming, adding the foam to the cementitious material slurry to make foam slurry, forming or cast-in-place, natural curing or autoclaved curing, has the characteristics of light weight, heat insulation, sound absorption and shock resistance, and is a new type of heat insulation material with waste utilization, environmental protection, energy conservation, low price and good performance, It is an ideal substitute for building thermal insulation materials of agricultural production system mainly based on polystyrene board. However, due to various reasons, the development of foam concrete industry has been restricted, which requires the joint efforts of the majority of colleagues in the concrete industry to analyze in detail many factors affecting the application of foam concrete, sort out a set of feasible solutions, and make contributions to the rapid development of China's construction industry [1].
1. Characteristics of foam concrete
1.1 Lightweight
The density of foam concrete is small, between 300~1800 kg/m3. Because of the small density of foam concrete wall , roof, floor, column and other building structures can generally reduce the dead weight of buildings by about 25%. Therefore, the use of foam concrete in construction projects has significant economic benefits.
1.2 High flow regime
Since the mixed foam is water film cement When mixing (sand) mortar, part of the foam will break into water. Therefore, foam concrete is a material with a large water cement ratio, generally more than 0.6, with high fluidity and self compacting characteristics.
1.3 Good sound insulation
Foam concrete is a porous material, so it is also a good sound insulation material. It can be used as a sound insulation layer on the floors of buildings, the sound insulation boards of highways, the top floors of underground buildings, etc; Foam concrete contains a large number of closed small pores, so it has good thermal performance, that is, good thermal insulation performance; It is an inorganic material and will not burn, so it has good fire resistance and can improve the fire resistance of buildings.
1.4 Foam concrete
Because of its small density and light weight, it can reduce the weight of the building itself and improve the seismic performance when used in building structures. In addition, it is a special porous structure with low elastic modulus, and the transmission speed of vibration waves is much slower than that of ordinary concrete structures. Therefore, it has good shock absorption effect.
1.5 Long service life
The design life of the building is generally 50~100 years, and the materials of general agricultural production system are not resistant to aging, so it is difficult to live with them. The durability of foam concrete is more than 50 years. One time thermal insulation construction can make the building lifelong thermal insulation, avoiding the shortage of multiple thermal insulation construction. In addition, foam concrete is mostly self insulated for walls, and there is no problem of external insulation layer falling off, which is incomparable to the insulation materials of agricultural production system.
1.6 Green and environmental protection
The use of insulation materials in agricultural production system will produce large toxic and harmful gases, which is harmful to health. Foam concrete is mainly made of inorganic materials, which will not produce task gases or toxic substances, and is green and environmentally friendly.
2. Application status of foam concrete in China
As the relevant departments in China not only pay more attention to building energy conservation, but also make remarkable achievements in the change of wall materials. Foam concrete, with its unique pore structure, gradually shows its important role in the field of thermal insulation, and is very popular. The application of foam concrete in building energy conservation is as follows:
1.1 Foam concrete compensation foundation
Modern architectural design and construction pay more and more attention to the free settlement of buildings during construction. Due to the different deadweight of each part of the building group, there will be free settlement difference during the construction process. During the design process of the building, it is required that the foundation of the part with lower deadweight of the building must be filled with soft materials as compensation foundation. Foam concrete can better meet the requirements of compensation foundation materials.
1.2 Real filling of road and bridge cavities
Filling foam concrete behind the pier can reduce the lateral pressure on the structure and also reduce the risk of settlement. Foam concrete can also be used for bridge facing, filling holes between bridge arch structures and bridge deck. Moreover, in bridge engineering, the bridge structure is very heavy, and foundation settlement often occurs at the junction of the bridge embankment. There is a high and low section between the bridge embankment and the bridge body, and vehicles will bump when driving on it. Therefore, some projects also use foam concrete backfill to balance the settlement of the foundation.
1.3 Application of housing construction
Foam concrete is often used for roof insulation and slope making, ground insulation, function transfer layer, garage, foundation pit, indoor stage, toilet, hotel decoration pipeline and other backfill works.
1.4 Application of road works
Abutment back backfilling, high-speed widening, soft foundation treatment, load reduction and replacement, cavity filling and other fields.
1.5 Application on subway
Construction road backfilling, roof load reduction and foundation pit backfilling.
