(1) basic composition materials;
The basic composition of aerated concrete consists of two kinds: calcareous material and siliceous material. Calcareous materials are mainly composed of calcium oxide (CaO) materials, such as cement, lime, water quenched slag, volcanic ash and so on. Silica material is mainly composed of silica (SiO2) material, such as silica, sand, fly ash, tailings powder.
In the process of production, the aerated concrete equipment has certain technical requirements for the chemical composition, physical properties and fineness of the basic composition materials, so as to ensure the quality of the products.
(two) gas material and bubble stabilizer
The gas generating material reacts with some substance in a hot alkaline slurry to produce gas. In principle, some metal powder (such as aluminum, zinc) or chemicals (such as hydrogen peroxide, bleaching powder, etc.) can be made of gas material, but from the comprehensive evaluation of several aspects of material sources and the cost and effect of gas, using aluminum powder as materials for most gas. The aluminum powder produces chemical reaction in the aerated concrete slurry and emits hydrogen. Hydrogen bubbles in approximately spherical form are uniformly distributed in the slurry, so that the volume of the slurry is expanded, and the porous silicate products are formed after hardening. When the aluminum hydrogen in the slurry system, internal surface area increases rapidly, the free energy increases, the system is very unstable, bubbles easily broken; therefore, in slurry is a surfactant added, namely bubble stabilizer.
(three) regulator
In some aerated concrete mixture slurry, the mixing agent should be added into the slurry. The purpose is to make the slurry pouring normally, accelerate the hardening of the body, improve the strength of the products and eliminate the cracks in the products. The regulator and selection of raw materials and product types and other factors, regulators are commonly used: soda ash, water glass, borax, magnesite and gypsum etc.. Some regulators such as sodium carbonate (Na2CO3) will bring some unfavorable factors to building applications in buildings often damp parts (such as window, eaves etc.), easy to salting out, make product surface spalling. Therefore, when we apply such products, proper measures should be taken in the construction, construction and decoration. And as in cement, slag and sand aerated concrete reinforcement plate, the body and the reinforced steel bar in high pressure in the maintenance of thermal expansion is consistent to avoid transverse cracks, the cracks are in use in the process of gradually exposed. So the amount of doped magnesia must be appropriate. It should be pointed out that due to the cracks caused by overload, will make the plate sag increase, because magnesite incorporation amount of cracks caused by improper distribution, more uniform, the vertical degree did not increase.
(four) steel bars and reinforcing bars preservatives
In reinforced concrete slab products, 3 steel reinforcement is adopted. The aerated concrete is a porous structure, high permeability, reinforcement in slabs susceptible to atmospheric corrosion and rust, corrosion, reinforced surface volume expansion will lead to expansion of concrete protective layer off, not only greatly reduce the durability of the reinforced plate, but also may be the occurrence of safety accidents, therefore, the steel surface aerated concrete plate must be coated with preservative. The preservative used in addition to the atmospheric corrosion of the steel bar, but also to ensure that with the aerated concrete has a good grip force.
