What does the brand of concrete mean: interpretation of

There are many indicators by which the quality of the concrete mix is ​​determined. These include frost resistance, water permeability, mobility and others. But the most significant parameter is its brand or class. This is what this article will be about.

Brand и класс бетона

These two parameters, denoting almost the same, are the main indicator of the quality of the mixture. They need to pay attention first. What kind of mortar is advisable to use, determines the instruction containing the engineering parameters of the constructed project. In the case of building a house with your own hands, you can focus on the recommendations of an experienced specialist.

The figure designating the brand of the mixture, determines its strength after pouring and solidification of concrete. This parameter, among other things, strongly depends on compliance with the technological process of manufacturing, supply and hardening of concrete. For example, the strength of a structure after three days or a week will be different.

The monolith reaches its design value only on the 28th day after the beginning of the process, but further its strength continues to increase.

The numerical values ​​of the grade and grade of concrete indicate the following:

1. Brand. Фиксируется цифрами от M50 до M1000. Установлена ГОСТ 26633. Показывает предел прочности на сжатие, то есть максимальное количество килограмм-сил, которое может выдержать 1 кв. см конструкции.
2. Class. It is denoted by numbers from B3.5 to B80 (according to GOST 26633) or from C8 / 10 to C90 / 105 (according to SNB 5.03.01-02 or STB 1544-2005). Reflects the number of megapascals that can affect the finished monolith without destroying it.

These two parameters can be compared. For example, C8-10 grade concrete and B10 grade concrete are about the same kind of mortar. The difference between the strength values ​​does not exceed 13.5%.

Determining the quality of concrete

In order to accurately determine the brand and (or) class of concrete, it is necessary to conduct a study in the engineering laboratory. A special press produces an effect on cubes or cylinders cast from the tested mixture, frozen for 28 days.

The value of the load that the sample withstood without the appearance of defects will be equal to the mark of the used mortar. For example, concrete grade 800 withstands exposure of at least 800 kgf / sq. cm, and concrete M 400 - respectively 400 kgf / sq. cm.

According to the regulatory documentation of the ST SEV 1406, the difference between the brand and its class is as follows:

• for the mark, the average value of concrete strength is taken (for example, M700 concrete is the averaged value plus or minus tolerance);
• For the class, guaranteed strength is used (for example, concrete of grade B 15 must withstand a pressure of at least 15 MPa).

Note! Despite the confusion in marking the construction sweep, most suppliers indicate the brand. The price is determined by it.

To make it easier for you to navigate, below is a table of the ratio of concrete markings.

Applications of some brands of concrete

Concrete M100

Low strength mortar is used for preparatory processes prior to casting monoliths and strip foundations. This is a well-known technology of concrete preparation.

For its implementation, a special sand pad is prepared, which is poured with the lowest grade solution - M100. After its solidification, iron fittings are laid.

Despite the importance of this event, many homegrown builders neglect it when they build summer houses and private houses, and block the vertical reinforcement bars directly into the soil. As a result, these parts are subject to corrosion, which could have been easily avoided.

In addition, lightweight concrete is used in the construction of roads for fixing curbstone. The filler here is limestone, granite or gravel rubble.

Бетон M350

This kind of construction is used to sweep away:

• castings of the monolithic foundations of residential buildings;
• construction of pile concrete structures;
• manufacture of floor slabs;
• child basseynov;
• beams and similar structures, the quality of which are increased demands.

Concrete brand 350 is great for the airfield plates from which aircraft taxiways are made. They are able to withstand extreme loads, including the effects of large masses.

Эта смесь, которая соответствует классу В25, повсеместно используется в современном строительстве. Большинство современных архитектурных проектов предусматривает использование бетона M350, так как готовые конструкции из него получаются более прочными и дешевыми.

For the production of this brand of building material, gravel or granite rubble is commonly used as a filler.

Concrete M400

This material is well suited for the manufacture of bridge structures, hydraulic structures, cash vaults and buildings with specific strength requirements.

Concrete brand 400 is used rarely enough. It is used only in cases where it is required by the relevant regulatory documents in the field of construction. For example, if it is intended to operate the constructed structure under rather difficult conditions, the controlling organizations often overestimate safety requirements.

In addition, during the construction of supporting structures of large shopping centers, water parks, parking lots and similar structures, which will contain a large number of people, concrete 400 can also be used. This will prevent the building from being destroyed as a result of possible resonant vibrations.

In the construction of private houses and small buildings, this construction brand does not apply.

This is due to the following reasons:

• стоимость марки M400 выше, чем M350, а прочность для большинства задач избыточна, что неоправданно завышает смету строительства;
• the mixture has a short setting time, as a result of which it cannot be transported over long distances;
• violation of the technological process may lead to hardening of concrete in vehicles or pumps, which will lead to additional costs for the restoration of equipment.

For the filler is used exclusively granite rubble. It is possible to add plasticizers that improve certain properties of the solution.

Heavy concrete

The brands of building concrete mixes are larger than M450, for example, M600 concrete belongs to the class of so-called heavy solutions. They are used exclusively for the casting of finished reinforced concrete structures.

An even greater value of strength, which is possessed by concrete M800 and higher, is used only in pre-stressed products.

When using them, it is imperative to take into account that the dense aggregate used in this mixture produces less shrinkage and creep, unlike the previously considered varieties. This leads to a decrease in the prestressing losses of metal reinforcement in the concrete product.

In addition, these types of mixtures protect the iron parts from corrosion, which is important in the case when it is supposed to use the produced elements in an aggressive environment.

Note! Do not confuse the labeling of the concrete mix and cement powder used in construction. These two values ​​are not related to each other, as other factors influence the density and strength of concrete, in addition to the brand of cement.

Cementing of concrete

As mentioned above, the strength of a concrete solution becomes as a result of its interaction with water. Builders to refer to this process use a special term - hydration. When it deviates from the norm, the concrete monolith will not be able to acquire the strength indicated in the regulatory documentation.

Negative effect on hydration:

• high temperature - as a result, moisture from concrete evaporates faster than required by the process;
• low temperature - moisture removal also occurs, but due to its freezing.

It is necessary to protect young concrete by covering it with sacking or polyethylene, as well as to apply various additives and plasticizers that prevent the formation of ice in winter.

Note! Young people consider concrete, from the moment of casting which 14 days have not passed.

Conclusion

Using this or that brand of concrete during construction, do not forget to observe the production technology. This is the only way to achieve the design value of the structural strength indicated in the marking of the building mixture.

The video in this article will provide more information on this topic.