Concrete brands - composition, features, characteristics.

Are you going to build a house, or did you start a large -scale repair? Have you decided to ennoble the personal plot with a bathhouse or a gazebo? Wonderful! But, the joy of the result is still so far and practical issues are not at all romantic, however, there is nowhere to get away from this. Although, it is possible to entrust the construction of a completely group of pros. But, after all, this will not save you from all problems, and control in such a case, far from superfluous! As they say, trust, but check. There are, to put it mildly, unscrupulous performers who seek to save a penny of another. So, knowledge is the power of the Lord!

We devote this review to issues related to labeling and concrete classes. After all, this is, in fact, the basis of any construction site. For example, a brand of concrete for the foundation is not at all similar to the characteristics of skinny concrete. And getting into trouble is quite simple.

Content:

1. The composition of concrete.
2. Characteristics of concrete mixtures. Indices and indicators.
3. Features of use and determination of the brand of concrete.

The composition of concrete.

The finished concrete mixture is a mixture of four components mixed in certain proportions.

• cement;
• sand;
• water;
• crushed stone

The class and brand of concrete is determined by the proportions of the components, the use of plasticizers, chemical. additives, etc. It should be understood that concrete marking is regulated by GOST.

A reasonable question arises why sand and crushed stone are added to the concrete mixture? Indeed, when a cement contact with water, the so -called cement stone is formed, which in itself has a phenomenal strength. However, this mixture is very easily cracking and sags, therefore, sand and crushed stone play the role of a structural skeleton, which arises the main load, amortizing and softening stress. In addition to the working characteristics, the aggregates significantly reduce the cost of the concrete mixture.

The inclusion of a large aggregate of crushed stone is spelled out in detail in the GOST-26633-91. Please note that the strength of crushed stone should be 2 times higher than the concrete brand itself. What is explained? While the concrete will gain its strength, usually this process lasts up to six months, the strength of crushed stone is enough to preserve the mixture, and prevent severe deformation. The ratio of concrete brands can be traced on the aggregates used. Consider its types:

- limestone, with a strength of 500 -600, is respectively used in the production of concrete, brands from M100 to M350.

- gravel is an average strength of 800-1000, a very practical and strong aggregate, so it is most often used to make a concrete mix. It is he who is chosen for private housing, because it costs significantly less granite aggregate, and also has a lower level of radioactivity. It can be found as part of concrete brands to M450.

- Granite, a unique aggregate strength, it is used to make heavy concrete. GOST, for example, obliges to build roads, a lush using concrete mixture based on granite.

Cement and water bind all components, create a homogeneous mass, the marking and classes depend on the components of these components no less. The brand of concrete cement determines its strength, for domestic needs, the use of the M300-M 500 brand is quite enough. The approximate ratio of the components is as follows: a large aggregate 4 \\ 10, sand 6 \\ 10, water 1 \\ 10, cement 3/10. However, all this is very approximate.

Characteristics of concrete mixtures. Indices and indicators.

Choosing concrete brands, characteristics play a major role. After all, you are looking for an offer that is optimal for your needs. Let us give an explanatory note that will help you navigate the sentences of a concrete mixture.

In any price, you will find a digital and letter index, which indicates a class and brand, the main parameters of concrete. What do they mean? Let's try to figure it out.

Brand of concrete m 100 m800. What is the number is the limiting strength of kgf \\ sq.cm. Near the brand in brackets, concrete class (at 3.5- B60) is a guaranteed strength coefficient +- 13%. By the way, a note to the owners, if you accepted the finished project from the developer, according to STS 1406, the classes of the necessary concrete mixture must indicate. Therefore, your knowledge is a guarantee of reliability and construction safety.

Concrete brands by frost resistance can easily be determined by marking. The letter F (25-1000) indicates the number of cycles of freezing, which withstands the mixture without succumbing to deformation. Manufacturers often use various additives to increase the resistance of the mixture by temperature differences. . Hydrophobic cement is often used. However, remember that the use of such materials negatively affects the strength of concrete. For our climatic belt, the use of a mixture with F100-200 indicators is quite enough.

Here, water permeability indicators have a deep connection, because Water, getting into microcracks, breaks out when freezing. In the concrete mixture passport, the coefficient of water resistance is indicated by the letter Wo (2 - 20). This index indicates the ability to resist the penetration of water under pressure. The parameters are strictly regulated by the current GOST 12730.584. Again, it is necessary to mention hydrophobic cement, it is often added to the mixture for higher rates. The higher the hydraulic flow indicator, the less you have to spend money on waterproofing, look for a place with a minimum level of groundwater. But, remember that the cost is this concrete is much higher! If you are trying to press the unique mixture at the lowest price, think about how would you not have to suffer in the future from such dubious savings.

But, no one prevents you from using various additives individually. If you find a qualified specialist, you can make an optimal solution in artisanal conditions!

The letter P in the passport of the mixture indicates the level of concrete mobility. The coefficient of 1 to 5. For example, the ideal brand of concrete for the foundation M 350 (in 25) has a level (P2-P4). It is this indicator that is rational for conducting standard monolithic work.

You can familiarize yourself with the ratio of indicators in the table below. Here you will find concrete brands, composition and proportions.

Features of the use and determination of the brand of concrete.

The simplest and most affordable brands of concrete M100 m 250 are usually used as an auxiliary material, in preparation for pouring a monolith, laying reinforcement, etc. The minimum strength indicators, and you will not find special additives in such brands.

The concrete mixtures of brands M 300-m 400 will be the ideal option for IZHS. They have excellent practical indicators, and their price is quite affordable. The brands of heavy concrete from M 500 can be found on sale very rarely. This is super -duty, and also moody material. Work with which requires professional high -level skill. Such a mixture is used in the construction of specific social use facilities.

How to determine the brand of concrete yourself? After all, our capitalist age makes you save not only buyers spend a little time. After the concrete is delivered to you, pour a couple of cubes. Moisten the wooden forms before that. Pierce the mixture with reinforcement in several places to form voids. And a week later, feel free to bring your masterpiece to any laboratory, there you will find out how conscientious the supplier turned out to be!

Good luck and success!