Basic classification of concrete

Classification of concrete is carried out by three main features: by design, by average density, and by the type of binding agent in the mixture. In its purpose, this material is actually divided into many subclasses. For example, in some conditions, higher heat resistance is needed, in others - resistance to shocks, etc. In each specific case, the optimal composition is selected, which will not allow the structure to collapse during operation.

In general, the following classification of concrete is designed according to purpose:

- special purpose materials (used in high radiation, acid environments, etc.);

- mixtures for sidewalks, roads, airfields;

- ordinary concrete (it is made of foundations, floors, various reinforced concrete structures);

- Hydrotechnical samples (used for sewerage, dams, canals, etc.).

Classification of concrete in density depends on which large aggregates are introduced into the composition. If the mixture contains pumice, tuff and other porous components, it can weigh from 0.5 to 1.8 tons per cubic meter (light concretes, including cinder, pumice, expanded clay). In order to produce particularly heavy samples (more than 2.5 tons / cubic meter), steel sawdust is introduced into the concrete. Such mixtures are used to create protective structures. Heavy concrete (1.8-2.5 tons / cubic meter) have in their composition diabase, granite or limestone.

Classification of concrete also gives off ultra-light mixtures, such as aerated concrete, foam concrete or foam silicate. Their weight per cubic meter is less than a semitone. Concretes of this class because of the increased cellularity have a low thermal conductivity, but at the same time low strength. Therefore, they are mainly used as facing materials.

The classification of concrete according to the types of binders is more than extensive. The most common substances today are silicates with the method of curing in an autoclave. Also, mixtures based on liquid glass, glass-alkaline components that are necessary for the formation of heat-resistant concrete are infrequent.

The most common are gypsum-based materials, from which are made elements of decoration, internal partitions, as well as mixtures for the production of waterproof coatings. In addition, there are widely used cement concretes (such as portland cement), slag-alkali (a relatively new product in the construction market), polymer-cement compositions.

Classification and properties of concrete are necessary in order to determine the main characteristics of the mixture and the future design. In particular, such characteristics as mobility (ability to spread under own weight), water resistance (at what pressure the sample in 0,15 meter does not pass water) are allocated for such compositions and, that is very actual for Russia, frost resistance. For example, concrete labeled F1000 can withstand a thousand cycles of thawing and thawing, which is especially important in regions with unstable weather, and sample F50 - only 50 such cycles.