Aerated concrete are stone materials of artificial origin, consisting of a certain binder and having a lot of air
shine cells that are evenly distributed inside. Now there are many types of them. Gradation occurs according to such parameters as the type of binder, scope, hardening conditions and others.
Classification
Depending on the binder, cellular concretes are divided into the following types - foam concrete and aerated concrete, foam gypsum and gas 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, a magnesian component.
According to such a parameter as the scope of use, concretes are divided into heat-insulating and structural-heat-insulating. The last mentioned cellular concrete products (blocks) are characterized by increased strength and can be used for the construction of load-bearing structures.
As for the way of hardening, there is a natural andartificial method. The first type hardens under the influence of atmospheric conditions, and the second - due to steam treatment.
History of Appearance
The first historical information about such building material as cellular concrete dates back to 1889. Then the Czech scientist Hoffman received aerated concrete by d
adding chloride and carbonic s alts to cement mortar. As a result, a chemical reaction occurred, as a result of which gas was released. Over time, the solution hardened, and a porous structure formed inside it. Fifteen years later, the Americans Dyer and Aulsworth used powder as a gas generator, which included impurities of zinc, aluminum and several other metals. As a result of the interaction, hydrogen was released, which played the role of an intumescent additive. It was this invention that laid the foundation for the modern production of aerated concrete.
A great contribution to the development of the production of this building material was made by the Swedish inventor Ericsson. In 1920, he proposed to swell the solution by adding siliceous substances and cement. Hardening in this case should have taken place in an autoclave at a pressure of 8 atmospheres. After that, cellular concretes in a similar way began to be produced in Sweden itself, and then in other states. Over time, two varieties of them were formed at once. The first of these 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, -cos
made of silica 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 with ordinary interior partitions and ending with load-bearing walls. The standard block size is 600x300x200 millimeters. However, others are produced on special order. In the case when the density of the plate is less than five hundred kilograms per cubic meter, it can even be used as a heat-insulating layer.
