B25 (concrete): characteristics and use

Concrete refers to the oldest buildingmaterials. Excavations of ancient human habitation on Earth showed that its use began over 6 thousand years ago. And now it remains, perhaps, the most common of the building materials. Consider in more detail one of its varieties - B25-concrete.

Quality of concrete

The main of the main indicators of the quality of concreteis the compressive strength. This characteristic class of concrete is indicated by the letter "B" (Latin) and the numbers corresponding to (in kg per square cm) the load allowed for it. Thus, the class of concrete B25 can withstand a load of 25 kg / sq. see Construction of concrete of this class, taking into account the coefficients are able to withstand a load of 327 kg / sq. cm, which corresponds to the strength grade M350.

Workmanship

This characteristic defines operationalquality of concrete when using it. In accordance with GOST 7473-94, this characteristic is identified by the letter "P" and the number from 1 to 5, corresponds to mobile concrete with a stiffness less than 4 seconds and is divided by the draft of the cone. In this case, the cone sediment is (in centimeters) 1-4, 5-9, 10-15, 16-20 and over 21 for grades P1 to P5, respectively.

Application area

Concrete B25 (brand M350) in recent years is very popular, thatIt is caused by toughened requirements to projects and increase of the control over their observance. This is the reason for the fact that this brand began to occupy the highest statistical positions in the sales of concrete products.

High strength characteristics providea large amount of quality cement in the composition of the material B25 (concrete). Therefore, this material is most applicable in the field of erecting multi-storey buildings, for the production of heavily loaded reinforced concrete structures (beams, ceilings, columns), including those intended for operation in aggressive conditions.

In its composition, B25-concrete mainly contains,except for cement, granite or gravel crushed stone and washed river sand. In the market of building materials it can be ordered with delivery in mixers-concrete mixers in the form of so-called ready-mixed concrete with mobility P2-P4.

Concrete B25 (grade M350) is characterized by highvalues ​​of frost resistance and water resistance. Therefore, it is widely used for the construction of monolithic foundations (slab, columnar, pile-grill and belt), as well as concrete staircases. From it in private households (and in the industrial sector) are cast basins, monolithic slabs and walls. B25-concrete is very durable and resistant to abrasion. Of this brand, in particular, road airfield slabs are used, operated in extremely severe weather conditions. In commercial construction it is also used widely with the aim of reinsurance and increasing the reliability of buildings and other facilities.

Concrete B25: price

The cost of this brand of concrete in modernconditions varies widely among producers. It depends on such factors as proximity to raw materials and product consumers, availability of own warehouse, transport and sales and sales base, and finally, from the manufacturer's reputation in the building materials market. The cost also depends on the degree of mobility of the concrete: the higher it is, the more expensive the material. The price varies, depending on the filler components. Usually gravel-based concrete is cheaper than a material based on granite rubble. Even cheaper material from secondary crushed stone, obtained by grinding concrete structures. On average, B25-concrete can be purchased (excluding shipping) at a price of 3000 to 3800 rubles. per m³.

Manufacture yourself

In cases of need for small volumesB25-concrete can be made by own strength. To do this, mix cement, sand and filler in the following volume proportions: for cement M500 - 1: 1.9: 3.6; for cement М400 - 1: 1,5: 3,1. Water is added in an amount that provides the required rigidity. In doing so, you must follow certain rules:

• use only clean tools and water;
• it is better to use washed sand, gravel or crushed stone (clay impurities significantly reduce the strength of the material);
• Do not add water after mixing the mortar (if added, the strength of the products is lost);
• Use the solution within one hour of cooking.

As a filler, gravel can be used,rubble of granite rocks, limestone or secondary. To produce concrete grade M350, fillers such as expanded clay, slag and other porous rocks that do not provide the required strength of the material are not used.

Thus, in this article we have consideredinformation about one type of concrete, the most applicable for structural products and buildings of high strength. We hope that the information given in the article will be useful to you.