Cement, Dry Mixtures, Mortar

Cement is an artificial astringent of inorganic nature. One of the basic and primary building materials. When adding liquid, or aqueous solutions of salts, or other liquids, forms a plastic mixture, which later hardens to form a solid body. It is used such a building material for the purpose of manufacturing concrete and various mortars. It is fundamentally different from other mineral binding materials (lime or gypsum), which freeze solely in the open air. The strength of this material is divided into grades, which are expressed in numbers from 100 to 600, meaning the compressive strength of 10 - 60 MPa. The material of the 600 mark is called "military" because of its own strength and area of use (for the erection of military buildings), and it costs much more than 500. Today this material is also divided into classes (from 30 to 60), which denote strength When compressed (MPa). The main difference from brands is that stamina is not as average, but asks for at least 95% quality, that is, 95 standards out of 100 must meet the class.

With regard to production, the cement is produced by a very fine grinding process of gypsum and clinker. Brick in this case is the outcome of a uniform firing until the sintering of a homogeneous mixture that consists of clay with superiority in the composition of calcium silicates and lime. When grinding clinker, cast gypsum in order to adjust the pour point, up to 15% of the functional mineral additives (pyrite, cinder, dust, sands, etc.) in order to improve some properties and lower the cost of the initial material. The firing of the initial mixture is carried out at a temperature of 1470 ° C for 2-4 hours in special long furnaces with built-in heat exchangers designed to facilitate the synthesis of suitable minerals of cement stone.

As you know, cement is such a material, without which none of today's construction can do. Only, how good the course of construction will be, it depends directly on the amount of interest given by the manufacturers to the quality of the building material. Despite the very possible misconceptions that a high-quality cement mix should be valued insanely expensive, it does not have to have a high price. Now, at a crucial time, manufacturers and implementers are trying to make a pricing system more profitable for both sides, in order to keep demand and competition, and quality is sometimes in no way inferior to European counterparts, although in the conditions of decline high-tech production is even more expensive. There are also variations of the cement mixture, which have special features. Such a mixture is indicated by separate signs: B - fast-hardening; C is sulphate-resistant and H is a mixture based on a normalized stone (normalized).

Fast-hardening cement is characterized by an active build-up of resistance during the initial period of hardening. It is used mainly for the manufacture of prefabricated reinforced concrete installations and products. The high mechanical reliability at the beginning of hardening is due to the proper mineral composition and texture of the clinker, the size of the additives and the fineness of the grinding. Sulphate-resistant mixture or sulfate-resistant Portland cement in relation to ordinary Portland cement has the highest resistance to the action of mineralized water, slowed-down adhesion and high cold resistance. For the concrete of track and airfield coatings, bridge structures, it is necessary to use a cement mixture, which is made on the basis of a normalized clinker.

The author is "www.ps24.by".