M250 concrete - composition, properties, scope of

Concrete M250, or rather concrete B20 M250 refers to structural solutions for concreting civil and industrial objects. We will tell you what the concrete grade M250 means, what are its composition and properties, and also show where this building material can be used.

Concrete marks М250

Definition and characteristics

Concrete is one of the most popular building materials, especially in terms of modern technologies, where the proportion of solid construction is constantly growing. In addition, the demand for prefabricated reinforced concrete products is constantly increasing, where the composition of concrete M250 is also used.

As is known, concrete is a stone-like material of artificial origin, which is obtained after hardening of a dry mixture, which consists of cement, crushed stone, sand, and some additives. One of the main characteristics of such a material is its compressive strength.

To determine this strength of concrete, a cube of frozen concrete with a side of 150 mm is subjected to a press test, as a result of which the average value of the force applied per square centimeter of the product surface, which this cube can withstand without serious damage, is determined. The value of the applied force is indicated in the marking with some approximation.

In our case, the brand M250 means that we have a material with compressive strength in the range of 250 kgf / sq. cm, or to be more precise, then 262 kgf / sq. cm.

Note! It must be said that this is rather scant information indicating the general class of material and its compressive strength. To clarify additional parameters, such as water resistance, frost resistance, tensile and flexural strength, bulk density, mobility, etc. knowledge of other indicators is required.

According to the classification of St SEV M250 corresponds to the class B20, which is considered the main step of this classification, whereas M250 in our country belongs to intermediate brands and therefore is used infrequently, which explains the low popularity and low demand for this product.

The main technical characteristics of the material can be represented in the form of such a list:

• Brand - M250;
• Class - B20;
• Compressive strength - 262 kgf / cm2;
• Frost resistance - F100 - F150, when using crushed granite - F The use of special additives can increase this figure to the desired value;
• Water resistance - W The use of granite rubble can increase the water resistance to W6, a further increase is possible with the use of special additives - water repellents, plasticizers and pozzolans;
• The density of concrete M250 is about 2350 kg / m3, which allows it to be classified as heavy grades. However, the specific gravity of concrete М250 may vary depending on the aggregates used, the water-cement ratio and the method of compaction of the solution, as well as on the sealing additives;
• The mobility of the finished ready-mixed concrete named brand varies depending on the requirements of casting and composition and may take values ​​of P2, P3, P4.

Note! Based on the list of characteristics, it is possible to define this type of concrete as a heavy material of medium strength and frost resistance, medium waterproofness and normal mobility, which makes it absolutely acceptable for civil engineering.

Composition

We consider the classic case of cement concrete, so its composition does not differ from other similar materials.

For the preparation of this type of concrete solution using the following components:

1. Binder. Portland cement of grades M400 - M500 is used here, which allows to achieve the most optimal water-cement ratio, while the price of the solution remains acceptable;
2. Fine aggregate. Use different types of natural sand, previously washed from clay and dust particles. There are no special requirements for it, it is enough to comply with GOST 8736-93;
3. Coarse aggregate. They use gravel, limestone and granite rubble, the first type being the most common, limestone is considered less durable and cold-resistant, and granite is considered too expensive. Crushed stone must be tested for strength, frost resistance and water resistance, it is desirable that these indicators exceed standards for concrete of this brand about two times;
4. Special supplements. The content of plasticizers in the production of ready-mixed concrete must be at least 5.8 kg / m3 according to GOST 8736-93. In addition, air-entraining, sealing, water-repellent, antiseptic and other targeted additives are added to the composition.

Note! If cutting of reinforced concrete with diamond circles, grinding or diamond drilling of holes in concrete is planned, then it is better to use limestone crushed stone, since it is better amenable to such processing.

Composition и пропорции бетона М250 на 1м3 согласно государственному стандарту принимается 1:2.1:3.9 по массе и 1:1.9:3.4 по объему для цемента марки М400.

If you are using cement grade M500, then this ratio will be 1: 2.6: 4.5 by weight and 1: 2.4: 3.9 by volume.

Note! If you need compliance with the project, where exactly such a grade is indicated, you should order delivery of ready-mixed concrete to the object. In the manufacture of the solution with their own hands, the instruction requires mandatory testing of the finished product in the laboratory, otherwise it is impossible to assign a brand to it.

Conclusion

Concrete mortar brand M250 is used for the construction of monolithic, strip and pile foundations, reinforced belts and bases, mauerlatov, lightly loaded floor slabs, platforms and paths, wall partitions and supporting walls in low-rise construction. The video in this article will show the process of applying and manufacturing this type of building materials.