Aerated concrete is a stone material of artificial origin, consisting of a certain binder and having a lot of air
cells that are evenly distributed inside. Now there are many types of them. Gradation occurs according to such parameters as the type of binder, the scope, hardening conditions and others.
Classification
Depending on the binder, cellular concrete is divided into the following types - foam concrete and aerated concrete, foam gypsum and gypsum, foam silicate and gas silicate, as well as foam magnesite and gas magnesite. In the first case, the binder is cement, in the second - gypsum of increased strength, in the third - limestone, and in the fourth - magnesian component.
According to such a parameter as the scope of use, concrete is divided into heat-insulating and structural-heat-insulating. The last mentioned products from cellular concrete (blocks) are characterized by increased strength and can be used for the erection of load-bearing structures.
As for the method of hardening, there is a natural and artificial method. The first type hardens under the influence of atmospheric conditions, and the second - due to the treatment with water vapor.
Appearance story
The first historical information about such building materials as cellular concrete dates back to 1889. Then the Czech scientist Hoffman got aerated concrete by
the addition of chloride and carbon salts to the
cement mortar. As a result of this, a chemical reaction occurred, as a result of which gas was released. Over time, the solution solidified, and a porous structure formed inside it. Fifteen years later, the Americans Dyer and Aulsworth used a powder, which included impurities of zinc, aluminum and several other metals, as a gas generator. As a result of the interaction, hydrogen was released, which played the role of an intumescent additive. This invention laid the foundation for the modern
manufacture of aerated concrete.The Swedish inventor Ericsson made a great contribution to the development of the production of this building material. In 1920, he proposed to expand the solution by adding siliceous substances and cement. Hardening in this case should have occurred in an autoclave at a pressure of 8 atmospheres. After this, cellular concrete in a similar way began to be produced in Sweden itself, and then in other states. Over time, two of their varieties formed at once. The first of them was gas silicate, which was concrete with a porous structure, which included a mixture of lime and silica additives. In 1934, a second species appeared - siporex -
consisting of siliceous elements and Portland cement.
Modern production and scope
Most often, cellular concrete (GOST 21520-89) is now produced in the form of blocks. They are considered one of the most common building materials (along with ceramic bricks). As for the scope, it is quite extensive, because everything is built from such blocks, starting from ordinary interior partitions and ending with load-bearing walls. The standard size of the blocks is 600x300x200 millimeters. However, others are also available on special order. In the case when the density of the slab is less than five hundred kilograms per cubic meter, it can even be used as a heat-insulating layer.