Density of concrete

Concrete is an artificial building material obtained by the formation and further solidification of a rationally selected and compacted mixture. It consists of cement or other astringents, as well as small and large aggregates with the addition of water. In some cases, where special density of concrete is needed, for example, in asphalt concrete technology, water is not added, but special additives are used.

Its main advantages are ecological compatibility, as well as the availability of a huge raw material base. It is possible to use it in different operating conditions. It can be called a universal material, which is intensively used in all areas and sectors of construction. It is chemically and heat-resistant, sound-absorbing and does not conduct nuclear radiation.

Mixing sand, cement, water and rubble allows you to get the required density of concrete. The ratio will depend on the moisture content of the rubble and sand, cement grade and fractions. In some cases, it will affect the amount and composition of additives: water repellents, plasticizers, etc. For example, to obtain a density of concrete M200, apply cement grade 400.

One of the important characteristics of this material is the water-cement ratio. There is a direct dependence of water / cement. That is, the lower this ratio, the stronger the concrete. A material having a density of 200 has a considerable mass (this is its only "minus"). It reaches 2,400 kg / m3. This concrete is excellent for load-bearing structures, columns, crossbars, etc. With too little water, the density of concrete is high and has low ductility. It is used as a basis for equipment, a blind area around the house , etc.

There is one mistake that is often allowed when kneading a solution. In cottage industry, too much water is often added, which reduces the density of concrete and increases its mobility. This in turn significantly reduces its strength.

For concrete, there is a classification that is made for the purpose, types of aggregates and binders, the conditions of hardening and its structure. By appointment, it is possible to distinguish the usual (for civil and industrial buildings) and special (road construction, heat-insulating, hydraulic engineering and decorating works) concrete.

By types of binding agent it can be plaster, silicate, cement, slag-alkaline (asphalt concrete, plastic or polymer concrete). Types of its fillers are also different: porous, dense and special, and its content is lean, fat and commodity. Also, the structure of concrete can be dense, porous, cellular and large-porous. The conditions for hardening are as follows: natural, heat and moisture treatment at atmospheric or autoclave pressure.

The main indicator in the characteristics of concrete is its compressive strength. It determines the class of concrete. For example, the density of concrete B25. This means that in 95% of cases this class will withstand a pressure of 25 MPa. That is, the letter "B" and the numbers indicate the pressure that concrete can sustain in megapascals. When calculating the strength index, it is required to take into account the coefficients of the normative compressive strength. This is suitable for the density of concrete B25. Age of concrete, based on its class, will be determined by the compressive strength and axial tension, which is assigned at the design stage. The possible methods of erection and design loads on the structure, as well as the conditions for hardening the concrete, are taken into account.

The density of concrete B 25 is ideal for floor slabs, monolithic foundations, pool basins. This is the material most often used for these purposes. In addition, builders use this material for other structures of responsible use. The density of concrete В 25 allows to guarantee the excellent quality of finished structures, provided, of course, that the purchased goods fully comply with the declared characteristics.