Everyone knows what cement is, however, not everyone knows what it is like. Cement is a powdered substance of white, most often gray, and refers to the astringent substances. For the manufacture of cement, calcium silicate or clay is used. These substances are thoroughly grinded and firing, which leads to a cement cliner. The quality will directly depend on the quality of the grinding of these substances – the thinner the grinders, the better the cement. Then it goes into implementation and is actively used in the construction, manufacture of building materials and mixtures. Several types of cement are known in the country, however, Portland cement is the most popular and common. This type is simply not replaced in the manufacture of reinforced concrete structures. In addition, cements may vary in marking. The labeling indicates what maximum weight can withstand 1 cubic meter. cm., That is, if the marking is M400, then the cement is able to withstand weight up to 400 kg. Based on this, it follows: in order for the solution to be stronger, it is necessary to use the cement of the highest brand. As a rule, it is advisable to use the cement of the highest brand to fill the foundation, since the foundation is in a more humid environment. And for the construction of walls you can use cement of lower brands. Also, it varies in the number of existing additives indicated by the letter D. The number near the letter D will indicate the number of additives. This means – if the packaging is the cement of the M400 D 20, then the cement will contain 20% of the additives. Both the strength and the elasticity of the solution may depend on the quantity and quality of additives. Cement m 400 d 20, for example, will have the qualities of water resistance and frost resistance. This shows the number of additives. Such cement is actively used in various construction and production of railway products, as well as in the filling of the foundation. But cement M 400 D 0 is also well used in construction, but in cases where moisture will constantly affect the solution. The process of hardening this does not last long, the start of hardening occurs after 40 minutes, and the end occurs after 12 hours. But cement m 500 d 20, has a low corrosion resistance. Its use is carried out in masonry and plastering, and is also added to construction solutions. And if you add cement m 500 D 0 in the composition of the concrete mixture, then concrete will acquire the qualities of durability, water resistance and frost resistance. Such cement is used in the implementation of emergency and recovery work. In addition to these brands, there are other varieties of cement. For example, sulfate, fast -hardening, cement made with standardization of the clinker composition. Quick -hardening has the ability to intensively increase strength already at the first stage of hardening. Such opportunities are of great importance in the manufacture of prefabricated structures from reinforced concrete. Sulfate cement has increased resistance from the exposure of mineralized waters. It includes sulfates, as a result of which the solution hardens a little longer. Such cement is very actively used in the construction of reinforced concrete structures, for example, at the bottom of the sea. Cement, with a normalized clinker, is used for road surfaces, airfield coatings, high -voltage supports, etc. D. No matter what marking is cement, it must be stored in dry places where neither snow, nor rain, nor groundwater falls. Most rational to pack cement in plastic bags. It is not recommended to mix cements of different brands, as well as with gypsum and other plaster mixtures.