The brand and class of concrete are one of the main parameters when choosing a concrete mix. They indicate the strength of the composition after the final secretion of the composition. It also defines the final value of concrete.
What is the difference between a brand from the class of concrete?
Mark - average strength indicator. Denoted by the letter "M" with a number. Strength is measured in kg / cm2. For example, the M150 brand will withstand the load of about 150kg / cm2. This parameter is not always applicable in the calculations during construction, since the level of accuracy is almost half different from the actual characteristics.
Class - load guaranteed by compressive strength. Denotes the letter "B" with indexes from 3.5 to 40. It is measured in MPa (megapascals). It is the most accurate indicator, as it is confirmed in 95% of cases. About 5% of the entire batch of mixture may not correspond to the stated strength. In addition, the concrete mixture with the same brand can have a different class. Production technology also affects this indicator. It may vary depending on whether concrete is made by manual concrete mixing or automated plant equipment. Class weakly for builders.
The classification is used when they talk about concrete, and the brand for solutions.
To prevent errors in the construction and determination of the appointment of concrete, tables of the ratio of stamps and classes are used. They may take into account the water permeability, frost, and other properties of concrete mixes.
An important role is played by the water permeability and frost resistance of concrete.
The frost resistance of the concrete mix is denoted by the letter "F". This indicator plays a role in cold climates or places with frequent temperature drop. Also, this parameter can be changed, but the price of concrete for 1 cube will also change.
The most sought-after stamps in Russia from the F50 to F150. They showed themselves well in our climate.
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The water resistance is indicated by the letter "w". This indicator directly depends on the porosity of the material. Dense heavy concrete have the smallest water permeability.
To increase the frost and moisture resistance of the concrete mixture, plasticizers and modifiers use.
It is an additional classification of concrete concrete along the axis and bending. These indicators are important in building in difficult conditions when it is necessary to avoid damage to the surface from the outside.
Usually concrete products are not intended for stretching. Nevertheless, the degree of stretching is taken into account at the stage of the project. This is done in order to correctly assess the load on the design. If this parameter is not taken into account, chips and cracks may occur. And also is the risk of premature destruction of the design.
The axial stretch parameter is important in the construction of pools, hydrostations, fountains and other water structures.
The stretching for bending is taken into account when laying roads, aircraft traps, etc.
