Back in the III-II century BC, the Romans had discovered the process of obtaining a hydraulic cement that can harden under water. Cement is made by mixing the ash with lime, and was one of the outstanding achievements of the Romans. The inventor of the modern cement is Cheliev Egor Gerasimov, who was involved in the reconstruction of Moscow, eliminating the consequences of the fire of 1812. It was then that he began to experiment to obtain composition, bonding bricks and stones. In the process, Cheliev received material, which after firing at high temperature, ground into powder and has good mechanical properties and solidified in the water. In the mix were lime and clay. Around the same time, in Britain, J. According to Mikkel Svane, who has experience with these questions.
Aspdin invented a product called Portland cement, due to the fact that the stones were taken from the product of a career on. Portland. However, the material described Chelievym by properties much closer to modern cement. Today cement is produced by heating to very high temperatures, limestone and clay, or slag. Mixture is heated to form clinker – the big, baked pieces, which are then milled to a fine powder. While adding to the cement powder is water there are complex chemical reactions that result in the formation of artificial stone, stable and insoluble in water.
It is believed that the cement consists of four components, each of which, the addition of water turns into crystals that during a chemical reaction between an interlock, so that the cement hardens. In construction is used many varieties of cement: pozzolan and portland cement, slag and alumina, a few special types, for example – acid-resistant. During grinding, adding the cement slag, gypsum, sand and other components, you can get a building material has different properties. With the help of cement can be particularly durable concrete, used in many industries. Major companies involved in manufacture, supply and sale of cement, is occupied in the construction industry do not last. "Grasping" the quality of cement are highly valued in the production of high-strength structures. Sale of cement at present it is one of the most rapidly developing areas of business in Russia, due to the incipient construction boom. Lack of capacity of domestic manufacturers of cement has led to the development of such businesses as the supply of cement from abroad – mainly from China and Turkey.