concrete classification is based on three main criteria: by appointment, at an average density, as well as by type of binder in the mixture.According to the purpose, this material is actually divided into a plurality of subclasses.For example, in some conditions you need higher heat resistance, in other - resistance to shock and others. In each case, select the optimum composition, which does not allow the construction to collapse during operation.
In general, the following classification is built on concrete purpose:
- special purpose materials (used in high radiation, in acidic environments, etc.);
- mix for sidewalks, roads, airfields;
- normal concrete (it is made foundations, floors, a variety of concrete structures);
- hydraulic engineering samples (used for creating drainage, dams, canals, etc.).
Classification concrete density depends on which coarse aggregates introduced into the composition.If there is a mixture of pumice, tuff, and other porous constituents, it may weigh from 0.5 to 1.8 tonnes per cubic meter (lightweight concrete, including slag concrete, pumice concrete, expanded clay).In order to obtain the most severe of samples (more than 2.5 tons / cu. Meter) is introduced into the concrete, steel filings.Such mixtures are used in the creation of protective structures.Heavy concrete (1.8-2.5 t / cu. Meter) are composed of diabase, granite or limestone.
Classification also provides ultra-lightweight concrete mixture, such as aerated concrete, foam or foamed silicate.Their weight per cubic meter is less than half a ton.Concretes that class because of the increased cellularity have low thermal conductivity but simultaneously lower strength.So basically, they are used as facing materials.
concrete Classification by type of binding agents more than extensive.Most materials today are the Non-Proliferation of silicates by curing in an autoclave.Also, rarely are found on the basis of a mixture of liquid glass, stekloschelochnyh components that are necessary for the formation of heat-resistant concrete.
most common are materials based on gypsum, of which make trims, interior partitions, as well as mixtures for waterproof coating.In addition, there are widely used in cement concrete (such as Portland cement), slag-alkaline (a relatively new product in the construction market), polymer composition.
Classification and properties of concrete are needed in order to define the basic parameters of the mixture and the future design.In particular, such compositions release characteristics such as mobility (ability to flow under its own weight), water resistance (pressure at which a sample of 0.15 meters is water), and that is very important for Russia, frost.For example, concrete labeled F1000 can withstand thousands of cycles of thaw-thaw, which is particularly important in regions with unstable weather, and the sample F50 - only 50 of these cycles.
