What is the classification of concrete?

Classification of concrete occurs by class, strength of the material, as well as by brand and purpose, which makes it easier to select buyers.

Concrete mortar is one of the building materials used to build a basic base.

With its application, various supporting structures are being constructed, including foundations and interfloor overlappings.

At the same time, for each concrete object, different types of concrete compositions can be used, which include various additives.

Due to what their classification is carried out according to the index of strength, degree of moisture resistance and frost resistance.

Types and technology of manufacturing of concrete compounds

Consider what are the classes and brandsconcrete and where they find their application:

• Cemented concrete - often used on building sites as a solution, is made on the basis of cement, most often, atPortland. Also for the production of cement concrete, slag-portland cement and portland cement can be used. Additions of decorative cement are not excluded: a tensile and non-shrinking binder;
• A special concrete mix - it is made on the basis of a special binder. Chemically stable and refractory properties of concrete are obtained by adding a mixture of liquid glass. As an astringent, slag, glass-alkaline and nepheline additives are used;
• Silicate concrete - is rarely used on construction sites, is made by adding lime binder. Solidification and the acquisition of strength is due to the use of autoclave technology. The technical properties of the silicate solution depend on the amount and fineness of grinding of quartz sand used in production;
• Slag-alkaline - made on the basis of ground slag, by mixing concrete with alkali solutions. In the construction of this type of concrete began to be applied recently;
• Polymer - for the production of polymer concrete a certain ratio of special resins, cement and latex is used;
• Gypsum - is made on the basis of an astringent - gypsum. Thermal insulating properties of these compositions allow them to be used for interior finishing works, in particular when erecting interior partitions;
• Cellular lightweight materials - classified as a lightweight type of concrete. Cellular concrete is made on the basis of a mineral binder and a siliceous mineral additive. In the construction of lightweight cellular products, most often, they are used for insulation of erected objects.

Classification of concrete solutions for strength

Classification of concrete composition by density or strength is carried out taking into account the type of filler. Additives are light and porous, special purpose and have different levels of density.

In addition, the additives are distinguished by fractions, which are the decisive factor in providing the products with basic technical characteristics.

The final properties of the materials are frost resistance, water resistance and strength. The most commonly used additives and fillers in the form of expanded clay, limestone, gravel, diabase and granite.

Classification of fillers and existing types of concrete density:

1. Lightweight concrete formulations - classified according to density, which can range from 500 kg / m3 to 1800 kg / m3.Lightweight materials are made using claydite, volcanic glass and other fillers that have a porous structure. Classification of lightweight concrete allows them to be divided into light cellular products, foam concrete and aerated concrete blocks;
2. Heavy concretes - when classifying such compositions, their strength indicators are taken into account, which can range from 1800 kg / m3 to 2500 kg / m3.Additives for heavy concrete are mountain rock, for example, granite or diabase;
3. Particularly heavy concretes are made with the addition of iron ore or using small metal waste. Solutions meet the strength index of 2500 kg per m3.

Classification of concrete mortars by grade

Classification of types of concrete mortars by grade is carried out in the interval: from grade 50 to grade 1000.

The specified value is determined taking into account the volume of cement added per unit of concrete solution. The strength of the concrete substance for compression is calculated in kg per cm2.

Based on this, the name of concrete grades is indicated by the letter M, with the numbers following it.

The large numerical designation indicates the high strength of solutions, and therefore, confirms its high quality.

In this case, the higher the grade of concrete, the more difficult it is to work with it, since the composition of high density hardens more quickly.

Therefore, it is very important to choose the right concrete mix according to the density index, which would ideally be suitable for the construction of a concrete object.

For example, in the manufacture of cushions for foundation casting, 100 or 150 concretes are used for road works.

In the process of manufacturing of bridges, paths and screeds, the increase of concrete grades occurs up to the index with strengths of 200 and 350.

At the same time, the M350 grade is considered oneof the common, since its universal properties meet all the necessary requirements for individual construction.

M350 is used in the construction of various types of foundations, during the erection of concrete steps and supporting elements of walls.

In addition, the brand 350 has found its application in commercial construction.

With its help, the foundations of solid construction, monolithic beams and walls, as well as road surfaces, whose properties can withstand large mechanical loads.

As a result, such brands as 250 and 300, quietly leave the construction market.

Technical characteristics of brands with high numerical indexes of 400 and 450 make it possible to use them in the construction of hydraulic facilities, with the expectation of high loads.

Higher concrete grades - M500 and M550, are used for the erection of structures with special technical requirements( metro, dam or dam).

Kinds:

Types of concrete materials in the

class Despite the accurately calculated ratio of the constituent components of the concrete, its strength characteristics may still vary.

This fact can be explained by the quality of the components used.

For example, during the preparation of the solution, water or sand of poor quality was used, which influenced the strength properties of the finished product.

In addition, inaccurate compliance with the production technology of the construction mixture, the characteristics of binding of the composition and technical.the conditions for its laying, also affect the obtaining of the same classification by the material of different strengths.

That's why the classification of concrete mixtures includes such a thing as a class.

This indicator is determined by the permissible error in the quality of the finished mixture, but with the condition that in 95 percent of cases, its density will correspond to the norm.

When labeling the product class, the letter "B" and the subsequent numerical designations indicate it. More common are: B-7.5;AT 10 O'CLOCK;B-15, 20.30.The full range includes classes from 3.5 to 80.

When drawing up project documentation for any construction work, it is correct to specify not the brand of concrete, but its class.

Although some projects still contain a brand designation, the table below shows the ratio of strength of concrete.

In addition, the classification of the material by brand and class is not only due to the constituent components, but also their proportions.

For example, in order to prepare a concrete grade M100 B-7.5 in accordance with existing standards, take cement M400 or 500. In what proportions should these types of cement be used, the table below shows.

Classification of concrete composition for the purpose of

Classification of this type of building materials for functional purposes makes it possible to make the right choice for the construction of a specific object.

As a rule, in the production of special brands of concrete, the problem associated with the operation of future facilities under extreme conditions is solved.

The requirements for their fire resistance, resistance to frost or vibration are usually increased.

The result of this classification is the concrete composition of special and general purpose.

In addition, in the construction market, there are hydraulic solutions and materials designed for the construction of runways of airfields.

Let's consider in detail the classification according to the functional purpose:

1. Concrete composition of general purpose - found its application in the construction of foundations, carrying reinforced concrete structures, slabs for interfloor overlapping, in the construction of columns and beams;
2. Compositions of special purpose - used in the process of erecting objects from which a high resistance to mechanical loads and the influence of the environment, including chemical character, is expected. With the help of special structures, nuclear power plants and other facilities are being built to prevent possible radiation leaks;
3. Hydrotechnical building materials are indispensable for the construction of hydroelectric power stations, construction of dams and water-pressure structures.