Concrete is a mass that is well compacted and mixed. It is obtained from a special material with the addition of water and other ingredients. The first is cement. During the production process, you should be guided by exact proportions, only then will the solution harden to a stone state and show durability and strength.
Currently, there are several types of concrete mixtures known, which are especially common in construction. Costs for concrete materials quite often exceed 20% of the cost of the building. This does not take into account the cost of concrete for the walls. This allows us to conclude that the choice of concrete is an important component of construction.
A significant factor is the processes of preparing and applying the solution. However, first you need to familiarize yourself with the main types and properties of concrete. Before hardening, the mixture of water, sand, gravel and cement has a liquid consistency. Among the main advantages finished design- resistance to stress, as well as durability. But under extremely high loads, the material can become cracked. In order to eliminate this, the prestressing method should be used.
Its essence is that the concrete mass is compressed with tensioned reinforcement. All tensile forces that act on the structure will be absorbed by the reinforcement. This allows you to increase the strength of the structure and the building itself, reducing the cost of reinforcement.
Classification of concrete
Considering the types of concrete and their classification, you can identify several types of this material. Among other factors that allow us to divide the composition into separate groups, the average density should be mentioned. One of the options for concrete is super-heavy, the average density of which is more than 2450 kg/m 3. Hematite and magnetite are used in the production process. These rocks are ore. They are first crushed into scale, shavings or sawdust. The material is used in the construction of nuclear power plants and when it is necessary to protect premises from radiation.
Another type of heavy concrete is the material of the same name, the density of which reaches 2400 kg/m 3. Whereas the minimum value is 1700 kg/m 3. This material is the most common type of mixture, because it is suitable for the construction of load-bearing and underground structures, as well as the construction of simple walls, foundations and partitions. The main component of the solution is crushed rock, among them:
- granite;
- diabasite;
- limestone.
Considering the types of lightweight concrete, we should highlight the composition of the same name, the density of which reaches 1700 kg/m 3. This mixture may have porous aggregates that are sometimes not even used. Aggregates may be artificial or natural. The structure inside has closed pores. Such concretes have good thermal insulation properties and are used in private homes.
Among the types of lightweight concrete is an ultra-light material, the density of which does not exceed 450 kg/m 3. Such mixtures are used as a heat-insulating cellular material, which has a large number of pores based on light porous fillers. Such structures are popular for their high thermal insulation and can be used not only for insulating floors, walls and ceilings, but also as an integral structure.
Types of concrete regarding structure
The modern market of concrete mixtures offers solutions that are also classified by structure. In this way, the material can be compacted. With this mixture, you can achieve maximum space filling; there are practically no free zones, which contributes to hardness and density. This material is made from fine and coarse aggregates, as well as a dense binder.
In construction, porous concrete is also actively used, which has an appropriate structure and is used in the construction of walls and facades. Cellular concrete is a mixture that does not contain aggregates. Instead, artificial rocks are added to the ingredients in the form of closed cells that are filled with air. This solution is common in the construction of one-story houses.
One of the most popular materials in construction today is concrete. A type of concrete that cannot be ignored is super-porous. Its structure is formed by coarse aggregate, which is not supplemented by sand rocks.
Types of concrete regarding binder and purpose of mixtures
Considering the classes of concrete, we can subdivide the material according to internal fillers. Sometimes the solution is made from cement. Such a mixture may include the following types cements:
- clinker;
- Portland slag cement;
- Portland cement;
- pozzolanic cement.
The resulting mixture is used in the construction of multi-story buildings. You can’t ignore silicate solutions that are obtained from limestone. During the production process, autoclaves are used, where the material is subjected to heat treatment, which increases its strength. If you decide to use concrete in construction, you should definitely study the types of concrete.
Among others, it is necessary to highlight gypsum mixtures, which have an impressive ability to absorb water. Such solutions are used in the construction interior walls and installation of ceilings. This material is widespread because of its budget. The mixture can also be slag-alkaline. Slag alkali acts as a binder. This solution is resistant to aggressive external factors.
But polymer mixtures are made from components of the same name, in which resins act as the main binder:
- furan;
- polyester;
- epoxy.
It is rational to use compositions on this basis for office or residential buildings. Excellent polymer mixtures have proven themselves in factories whose activities are aimed at chemical production and metal processing. This is due to the fact that concrete has high stability and wear resistance in relation to thermal conditions.
Special concretes
Special types of concrete are mixtures that are made with the addition of components water based. Polymers are used as a hardening ingredient. Moreover, they are binder and strengthen the fastening of elements in concrete. The mixtures have good tensile strength, are frost-resistant and have water-repellent properties.
Classification of concrete according to purpose
The concretes described in the article can also be classified according to their intended purpose. Thus, the compositions can be structural. They are intended for the construction of load-bearing structures and floors. Such solutions perfectly withstand force loads. The main advantages are resistance to deformation, strength and the ability to use at low temperatures.
Structural and thermal insulation compositions are solutions that are widely used in external structures, in the construction of facades and fences. The main feature of these concretes is their ability to provide thermal protection. Considering the main types of concrete, you will pay attention to thermal insulation mixtures. They are used to provide high thermal resistance, which is why they are used for building envelopes. The material allows you to form a small layer, but it can be used as load-bearing structures.
Thermal insulation concretes can be applied to the surface of ordinary concrete structures. Among others, it is necessary to highlight hydraulic mixtures that are used to ensure high density, frost resistance, water resistance and resistance to aggressive external conditions. These concretes are popular in the northern part of the country, where they are used for the construction of residential buildings.
The article presents the types of concrete and their application. Among others are road concrete mixtures, which are used as the top layer of the road and on the airport runway. This class of material is characterized by high resistance to cracks and deformations. The structure does not collapse under the influence of temperature changes.
Concretes, the types, properties and applications of which are described in the article, can also be chemically resistant. They tolerate the effects of alkalis, acids and salts well. They have unique characteristics and boast high wear resistance, as well as excellent resistance to exposure to vapors and chemical compounds. This concrete serves as insulating material, and you can apply it to the finished layer. But chemically resistant compounds cannot be used for load-bearing structures.
Purpose of heat-resistant concrete
When considering concrete, the types and purposes of this material should definitely be studied. Among others, there is a heat-resistant composition that retains the necessary physical and mechanical properties under prolonged exposure to elevated temperatures. Such compositions are used for production facilities as load-bearing structures, which are subjected to high temperatures.
Purpose of decorative mixtures
Before using concrete in construction, the types of concrete must be studied. Among others are decorative compositions that are used for texture processing during finishing work. This mixture can be found on the external surface of buildings and structures. Concrete structures match the selected texture and color. The material has increased resistance to atmospheric conditions.
Basic properties of concrete
Among the main indicators that characterize concrete is compressive strength. It determines the class of the material. For example, the designation B25 indicates that a standard concrete cube of this class will be able to withstand a pressure of 25 MPa.
To determine strength, coefficients should be taken into account. For the above-mentioned material in terms of compressive strength, the standard resistance will be equal to 18.5 MPa, while the design resistance is 14.5 MPa. Along with classes, the strength of the material is specified by grades, which are designated by the letter M and a number ranging from 50 to 1000. It means the compressive strength in kg/cm². If you decide to use concrete in construction, the types of concrete should definitely be considered. They are also divided according to ease of stacking. Based on this feature, the material is designated by the letter P and can be divided into concrete:
- hard;
- super hard;
- movable.
Among the others important indicators it is necessary to highlight:
- bending strength;
- frost resistance;
- waterproof.
As for frost resistance, it is designated by the letter F and numbers from 50 to 1000, which indicate the number of freezing and thawing cycles. But water resistance is indicated by the letter W and numbers from 2 to 20. They indicate the water pressure that the cylinder-shaped sample will be able to withstand.
Types of concrete by brand
In order to receive good concrete, you should follow the technology of its manufacture and adhere to recommendations on proportions and composition. The composition largely depends on the purpose and responsibility future design. For example, for concrete grade M100, less cement will be consumed than for concrete grade M400 or M500. Most often, ready-mixed concrete is made from cement grades M400 and M500 using sand, crushed stone and various additives. The latter can be anti-frost.
When determining proportions, many factors should be taken into account, including:
- sand fraction;
- density;
- frost resistance;
- mobility;
- waterproof.
Considering the types and grades of concrete, we can identify a material that is designated by the letter M and numbers ranging from 100 to 450. The mass composition for the M100 concrete grade is as follows: 1: 4.6: 7.0. IN in this case We are talking about the ratio of cement, sand and crushed stone. But if it is necessary to prepare the M250 concrete grade, you should combine the above components in the proportions: 1: 2.1: 3.9. In order to make M400 concrete, cement, sand and crushed stone should be combined in ratios of 1: 1.2: 2.7. In this case, we are talking about a solution that is made from M400 cement.
In addition to the brands, it is worth mentioning that there are M50-M1000 concretes. The specific brand you choose will depend on the strength required and the area of use. IN project documentation you can find the brand of the solution. If there is none, then you should trust the builders or make the choice yourself. Some believe that the grade of concrete depends on the grade of cement. However, the first is assigned taking into account the proportions used.
Conclusion
Concrete, the types and properties of which were described above, is presented today in a wide variety. Therefore, builders should think about which mixture to choose. You should not make a rash purchase. It is important to decide on the goals you are pursuing and the loads that concrete structures will withstand.
It is important to pay attention to deformation and strength indicators. If these aspects are taken into account, then selecting a concrete mixture will be quite simple. For example, if you want to make a structure with high water resistance, then you should purchase or prepare a hydraulic solution. It is used to construct buildings that will be used in swampy areas.
In this article:
Concrete - main material construction, prepared using a certain technology. Additional ingredients in its composition help improve structural and technical specifications concrete.
This building material is usually classified according to 6 main characteristics: purpose, type of binder, medium density, strength, frost resistance and water resistance.
1. As intended
The production of various types of concrete mixtures depends on the conditions where future iron will be used concrete structures. The conditions can be very specific: fire resistance, sulfate resistance, resistance to stress, shock, vibration.
According to their intended purpose, the following types of mixtures are distinguished:
- ordinary concrete is used to create beams, columns, foundations, and floors;
- certain types are used for road, airfield pavements and sidewalks;
- Hydraulic concrete is used for lining dams, locks, canals, and water supply structures;
- release concrete special purpose, for example, heat-resistant or acid-resistant, as well as for radiation protection.
2. By type of binder
The most important factor that determines the properties of a concrete mixture is the type of binder.
The main types of concrete in this category:
Gypsum concrete
Based on gypsum it is obtained gypsum concrete, which is used in finishing elements, for the manufacture suspended ceilings and internal partitions. Gypsum-cement-pozzolanic mixtures with high water resistance are widely used; they are used to create bathroom blocks and various designs low-rise buildings.
Cement concrete mortar
Based on cement components they produce cement concretes and mortars. The most common raw material component is Portland cement and its varieties. Concrete mixtures based on Portland slag cement and pozzolanic cement are also widely used. The use of this type is construction.
This category includes decorative concrete, which is produced on the basis of colored, white cements. The idea of creating a decorative building material came to us from Germany. Concerning color range concrete, it includes green, black, brown, blue, yellow, red and white shades. White concrete is considered especially expensive. There are also concrete mixtures based on non-shrinking, tensile and aluminous cement.
Slag-alkali concrete
Recently they began to use in construction slag-alkaline concrete. It is produced from slags mixed with alkali solutions. This type of concrete is indispensable when creating massive objects.
This is explained by the fact that when creating large structures from a mixture of Portland cement, a large amount of heat is released, and the temperature building elements can reach 80°. If such an object cools very quickly, cracks may appear. The use of slag-alkaline concrete avoids this problem.
Polymer cement concrete
With mixed binding basis get polymer cement concrete. In this case, the base contains latexes, water-soluble resins and cement. When this mixture cools, a film appears on its surface, swelling in the presence of a large amount of moisture.
There are two types - framed and filled.
Application.
The material is actively used for landscape design, outdoor and interior decoration walls, building facades and when installing floors. Polymer cement concrete convenient to use, easy to apply both mechanically and manually.
Acid-resistant and heat-resistant concrete
Special binders will be needed to obtain special concrete. To obtain acid-resistant and heat-resistant concrete, they use liquid glass, slag, glass-alkaline elements as binders.
Silicate concrete
A very rare type of concrete, practically unused in modern production – silicate concretes. Their production is based on the use of lime, where there is an autoclave hardening method.
Dense autoclaved silicate concrete is used to create load-bearing panels for internal walls and large blocks, as well as floor panels. Especially durable building materials are used to create railway sleepers and slate, which do not contain asbestos. Also, silicate concrete can be used for constructing road bases and in tubes for mine construction. There are also combined types of concrete made from the combination of 2-3 binder components. Such compounds can often be found in the composition plaster mixtures, where lime, gypsum, cement and other elements are combined in a single composition.
3. By average density
The main factor influencing the water resistance, frost resistance, and resistance of a concrete structure to compression is density. The significance of density is determined by large aggregates: dolomite, expanded clay, diabase, gravel, granite, limestone. Following compliance with GOST, concrete grades are distinguished within the range M50-M800.
Based on density parameters, the following types of concrete can be distinguished:
- Light or lightweight, which are produced on porous aggregates: tuff, expanded clay, pumice. Its density is 500-1800 kg/m3. The corresponding marking according to GOST is M50-M450. This type includes varieties of lightweight concrete - cellular concrete (aerated concrete and foam concrete), produced by swelling of a binder and water. This category includes large-porous concrete with lightweight aggregate. Their brands are M50-M150.
- Heavy concrete produced from rock fillers: limestone, granite, diabase. Its density is 1800 - 2500 kg/m3. Compliance of this brand with GOST M50-M800. Heavy concrete was used in the construction of industrial and civil buildings as reinforced concrete and concrete structures, as well as in the construction of hydraulic projects, canals and transport structures.
- Particularly heavy concrete with a density of over 2500 kg/m 3 is created from steel filings, shavings, and iron ore. It is used for special structures designed to withstand radioactive substances.
Each brand of concrete determines its strength class. For the construction of the least critical structures, grades with lowest value— M50, M75, M100. For example, this is the least durable concrete suitable for the construction of a blind area. To screed floors or railway floors, you will need concrete of higher strength, for example grade M200.
M550 concrete is considered the most durable.
The different strengths of all types of concrete depend on the proportions of sand, cement and crushed stone in its composition. High strength is achieved by the impressive presence of cement.
4. Frost resistance and water resistance of concrete
There are also grades of concrete according to frost resistance, which in GOST are marked with the letter F. Frost resistance is characterized by the largest number freezing and thawing with a decrease in mass and strength by a certain amount. The densest concrete mixtures are always the most frost-resistant. In this category there are concrete grades from F25 to F1000.
The ability of concrete not to allow water to pass through under pressure is called waterproof.
Concrete grades according to this classification are W2, W4, W6, W8, W12. Several years ago, the Russian letter V was used to denote this parameter.
What is the classification of concrete?
It is impossible to imagine modern construction without the use of concrete, which is the main building material prepared according to special technology. The introduction of additional ingredients improves the performance characteristics of concrete and changes their structure.
Being the main material used in the construction of objects, concrete is used for the following purposes:
- production of prefabricated reinforced concrete structures;
- pouring monolithic reinforced structures.
The classification divides mixtures into varieties used to perform interior works, outdoor events.
Solutions differ in their purpose, type of binder, density, strength characteristics, water resistance, resistance to low temperatures, and structure. Let's consider the features of various solutions and their characteristics.
Concrete is one of the basic building materials that no construction site can do without.
Purpose
The specific operation of reinforced concrete products requires the use of various concrete compositions. The main emphasis is on how monolithic design will behave during operation. At certain situations increased resistance to fire, vibration, somewhere susceptibility to impact forces, sulfate resistance are required.
Depending on the specific area of use, the following types of solutions exist:
- Structural purposes, which are traditional, used in structures that are subject to applied external forces - beams, floor slabs, columns, building foundations. The compositions are resistant to deformation, low temperatures, and have increased strength.
- Thermal insulating and structural compositions used for the manufacture of external walls of buildings, coatings and enclosing structures. Their feature is the ability to absorb loads while providing thermal protection to the object.
- Mixtures for thermal insulation purposes, which, with a small material thickness, can provide high thermal insulation structures built from traditional concrete.
- Solutions intended for hydraulic engineering applications, which, along with high strength and resistance to deformation, have significant resistance to water permeability, temperature changes and are able to withstand exposure to aggressive factors for a long time.
Concrete mortar belongs to the category of building materials used to construct the base
- Possessing chemical resistance to the effects of alkalis, salts, acids, which retain their performance properties for a long time and are used as the main building material or protective layer of concrete structures.
- Mixtures for road construction, used for coatings and airfield sites, which are distinguished by their strength, significant wear resistance, and are not afraid of alternating changes in humidity and temperature.
- Solutions that are highly resistant to high temperatures while maintaining their physical characteristics, mechanical properties. They are used for technological needs when heating occurs during operation, during which it is necessary to maintain strength.
- Solutions for decorative purposes, characterized by resistance to atmospheric factors and used for finishing works of various building structures. They differ in their structure, color scheme, and have enhanced aesthetic characteristics.
- traditionally used cement mortars, the main component of which is Portland cement and its varieties containing slag, alumina, various non-shrinking, prestressing, and colored types of cements. This group includes decorative material, offered in a wide range of colors;
- lime-based silicates produced using autoclave technology with impact on the massif high humidity, temperature;
- gypsum mixtures intended for the manufacture of internal structures used in the construction of objects - partitions, finishing elements and suspended ceilings. The main ingredient is gypsum, which, together with special ingredients, ensures high water resistance of structural elements;
- polymer cement mortars, based on water-soluble resins, latexes, and various cements. They are resistant to aggressive influences chemical substances, elevated temperatures and are used in the chemical and foundry industries, in the processing of agricultural raw materials, as well as for the manufacture of special tanks where acids are stored;
- alkaline-based concrete solutions, characterized by significant resistance to the aggressive effects of various factors and increased strength;
- cement-polymer mixtures obtained by mixing solutions of polymers with ordinary concrete, which are distinguished by a significant level of resistance to tensile loads, resistance to freezing cycles, and chemical resistance.
- Light mixtures with a density of 0.5-1.8 t/m3, based on porous fillers such as pumice and expanded clay. This category includes cellular materials - aerated concrete, foamed, porous mixtures obtained by swelling of the binder during a chemical reaction of a special additive dissolved in water.
- Heavy compounds with a density of 1.8-2.5 t/m3, used in the construction of critical structures. They are in demand for hydraulic structures, transport, industrial facilities located above and below the zero level - the foundations of buildings, columns, walls, beams. Dense crushed stone, large diabase granite or limestone are used as filler.
- Solutions with increased density up to 2.5 t/m3, classified as particularly heavy, based on steel filler, cast iron shot, iron ore ingredients. This type of mixture is used as radiation protection during the construction of power supply facilities.
Features of binders
One of the main points that determine the properties of a concrete solution is the type of binder used. Depending on the binder for concrete, they are divided into the following types:
Cement concrete– a type of mortar often used on construction sites, made on the basis of cement
Difference in density
Density is one of important properties, which determines the stability concrete product to moisture permeability, exposure to negative temperatures and resistance to compressive loads. The specific gravity is affected by the size of the aggregates used - gravel, granite, expanded clay, limestone and other materials.
Concrete is classified according to class, material strength, as well as brand and purpose.
Depending on the density, the compositions are divided into the following types:
Strength characteristics
Concrete is a very well mixed and compacted mass, which is obtained from a special material (cement) with the addition of water in particularly precise proportions, which subsequently hardens to a stone state.
The types of concrete mixtures described in this article are the most common at the moment. Once you get acquainted with them, you can learn a lot of new things for yourself.
In our twenty-first century, the variety of concrete is simply off the charts. It is used in the construction of a wide variety of objects. For example, to create the foundation of buildings, ceilings for basements, protect already applied concrete mixtures from various external factors, to construct stairs, create load-bearing structures, walls, and so on.
Attention ! The cost of concrete materials often amounts to 15-20% of the cost of the entire building, although this does not take into account the cost of concrete for the walls. Based on this, we can conclude that the selection of concrete is the most important component of construction.
An important factor is the processes of preparing and applying concrete. But in this article we will not talk about this, but about what types of concrete there are and what this is connected with.
Concrete is most often used in construction various rooms. Very few specialists in their field are engaged in construction, especially if the owner decides to build a house on his own, not being a professional in the construction industry. Often, without first becoming familiar with the entire “palette” when choosing concrete mixtures, he thereby exposes his future construction to premature destruction, deformation and low strength under all kinds of external influences on the object. It is important to remember that the correct choice of concrete mixture is fifty percent of the success in building construction. By making its base strong, you will be sure of its reliability for many years!
Until it hardens, the resulting mixture of sand, water, gravel and cement is a concrete mixture. The main indicators among the advantages of concrete are its excellent resistance to loads, compression and tension.
But this is not enough to use concrete alone to build structures that will be designed for high loads. To increase its strength, reinforcement is used, which perfectly absorbs all kinds of tensile forces that can affect a concrete structure. The combination of reinforcement and concrete is called reinforced concrete.
It happens that even this is not enough, when cracks can form as a result of extremely high loads. For such situations, builders have developed a method of “prestressing concrete.” Its essence is that the poured concrete mass, which is subject to tension, is compressed with tensioned reinforcement. As a result, all tensile forces acting on the structure will be absorbed by the reinforcement and not the concrete.
Important ! It is worth noting that the use of such a design in construction not only increases the strength of buildings, it also significantly reduces the cost of reinforcement.
Classification of concrete
Concrete is classified according to its average density per cubic meter and are divided into:
- super heavy - over 2450 kg/m 3. Extra-heavy concrete is made from materials such as magnetite and hematite. These are ore rocks that are crushed into sawdust, shavings and scale. Such material is used only in the construction of nuclear power plants, to protect premises from radiation;
- heavy - from 1700 to 2400 kg/m3. Heavy concrete is the most popular look mixtures, it is highly popular in the construction of underground and load-bearing structures, as well as in the construction of simple walls, partitions and foundations. The main component of this mixture is crushed stone from rocks such as limestone, diabasite, granite, etc.;
- light - from 250 - 1700 kg/m 3. The group of lightweight concrete includes mixtures that contain porous aggregates (both artificial and natural), sometimes even without aggregate, using artificial closed pores inside the concrete mixture. Typically, lightweight concrete is used as a durable thermal insulation structure in private homes;
- ultra-light - up to 450 kg/m 3. Ultralight concrete mixtures, as a rule, act as thermal insulating cellular concrete, which has a large number of pores created on the basis of lightweight porous aggregates. Concrete structures of this kind are distinguished by their high thermal insulation and can be used not only for thermal insulation of walls, floors or ceilings, but also as an integral structure from the influence of external temperature factors.
Type of concrete relative to its structure
On the modern market, concrete mixtures can be found with the following structures:
- compacted. Compacted is a structure in which they try to achieve maximum filling of the space in the concrete itself, i.e. do not leave free zones that could reduce the density and hardness of the material. This kind of concrete is made from large and small aggregates and a dense binder.
- porous. The porous structure is filled with a binder in a porous state. Used in the construction of walls and facades.
- cellular. A cellular structure is considered to be a concrete mixture that does not contain any aggregates. Instead, it is filled with a large amount of artificial rock in the form of closed cells filled with air. This structure is widely used in the construction of one-story houses.
- super porous. A structure of this kind appears only in the form of one large aggregate, without the use of sand rocks.
Video on what types of concrete there are:
Type of concrete relative to the binder
If we consider the classes of concrete according to its internal fillers, we can distinguish the following:
- based on cement. Cement concrete is a mixture based on clinker, Portland, Portland slag and pozzolanic cements. This is the most common type of concrete. It is used in the construction of multi-story buildings;
- silicate mixtures. Concrete from such mixtures is produced on the basis of binder limestone. In the production of this type, autoclaves are used, where concrete is subjected to heat treatment to increase its strength;
- gypsum mixtures. This type of concrete mixtures has high water absorption. This kind of concrete is used in the construction of interior walls and ceilings. It is also worth noting that it is a budget material;
- slag-alkali mixture. Concretes based on slag alkali act as a binder. This mixture uses ground slag. This material is highly resistant to harsh external conditions;
- polymer mixtures. In concrete mixtures based on polymer components, the main binding components are: epoxy, polyester and furan resins. It is not rational to use mixtures on this basis for residential or office buildings;
Important ! This kind of material is used exclusively in the construction of plants involved in the chemical industry and metal processing. Where high wear resistance and resistance to all kinds of thermal conditions are required.
- special concrete mixtures. Such mixtures are produced with the addition of water-based polymer components, which act as a hardening component when used. The polymer components used are excellent binding agents. They strengthen the bonding of elements in the concrete body. This kind of mixture has excellent tensile strength, frost resistance and boasts excellent water-repellent properties.
Type of concrete regarding application area
Given the versatility of the construction industry, concrete is also made in relation to the purposes for which it is intended. They are:
- structural - these mixtures are intended for general use. Usually used in the form of load-bearing structures of buildings and floors. They are able to withstand high force loads. The main advantage of this type is high strength, resistance to deformation and the ability to use at extremely low temperatures;
- structural and thermal insulation mixtures. These materials are widely used in external structures, namely in the construction of fences and facades. The main feature of this concrete is its high thermal protection;
- thermal insulating concrete mixtures. This type of mixture is used for buildings and factories, mainly factories where it is necessary to ensure high thermal resistance for enclosing structures with a small layer. Wherein this type not used as load-bearing structure, thermal insulating concrete is applied on top of already installed concrete structures;
- Hydraulic concrete mixtures are concrete mixtures that are used to ensure high density, water resistance, frost resistance and resistance to harsh external conditions. This type of concrete is very common in the northern part of the country, where it is used for the construction of residential buildings;
- road concrete mixtures. These are substances used for application as a top coat on roads and also on airport runways. This class of concrete is highly resistant to deformation and cracks. Does not collapse under the influence of temperature changes;
- Chemically resistant mixtures. Concrete mixtures of this kind are resistant to salts, acids and alkalis. Along with these unique characteristics, this type of concrete mixture boasts high wear resistance under the influence of various chemical compounds and vapors. This type of concrete inherently serves as an insulating material. It is applied to a ready-made layer of concrete;
Important ! It cannot be used as a material for load-bearing structures.
- Heat resistant. These mixtures maintain the required physical and mechanical properties within the required limits, even with prolonged exposure to elevated temperatures. They are mainly used for production facilities as a supporting structure, which may be exposed to high temperatures during operation.
- Decorative concrete mixtures. This material is used for texture processing when finishing works on the external surface of buildings. Concrete structures of this kind must match the chosen color and texture. They should also have increased resistance to atmospheric changes.
Bottom line
I would like to note that in view of such a wide variety of concrete mixtures, it is worth thinking about how to choose the right one. Don't make a rash purchase. First of all, decide on the purposes for which you need the concrete mixture, then on the conditions in which it will be used, and then pay attention to the strength and deformation indicators. If you take these three aspects into account when selecting a concrete mixture, then in this case you simply will not make the wrong choice, and you will be satisfied with the purchase for many years.
This material is an artificial stone, the production technology of which depends on the properties that need to be imparted to the final product. The composition of the mixture for preparing concrete includes such basic components as binder (most often cement, sometimes other substances) and filler. As a rule, water is added, but in rare cases it can be done without it. In order to give concrete certain pronounced qualities, appropriate substances called additives are introduced into the mixture.
Already from this it becomes clear that by changing the proportional ratio of the components, selecting certain ingredients for preparing the solution, you can regulate various characteristics concrete. Therefore, such a variety of products should be classified to make selection easier optimal option for use in specific conditions. Mistakes here are unacceptable; a reinforced concrete truss requires a completely different class than, for example, the foundation of a bathhouse, otherwise the structure will be unreliable.
The fundamental document defining the classification of concrete is State standard No. 25,192 of 1982. According to him, they all differ:
- by structure;
- by filler;
- by astringent;
- according to hardening conditions.
On the Internet you can find some other criteria by which artificial stone is distinguished. So that a person who does not have special knowledge in the field of building materials, could better understand the variety of characteristics of concrete, we present a generalized (more complete) classification of them.
Concrete by structure
- Dense.
- Large porous.
- Porized.
- Cellular.
By astringent
- Cement.
- Lime (silicate concrete).
- Gypsum.
- Slags.
- Mixed compositions (cement + lime, slag + lime, cement + polymer and a number of others).
- Special. There are inorganic and organic binders, which are used to adjust the characteristics of concrete in order to give the product special qualities.
By density
Extra light
Their density does not exceed 500 kg/m3, and such products are used mainly for additional insulation structures and for sealing seams, joints, sealing large cracks. They are produced by the “expanding” method (gas, slag, foam concrete).
Lungs
They are mainly used in the construction of elements that are not subject to heavy loads, since their density is from 500 to 1,800 kg/m3. “Light” fractions (expanded clay, tuff, pumice, agloporite and others) are used as filler.
Lightweight
1,800 – 2,200 kg/m3. Thanks to this characteristic, concrete is more versatile and can be used in the construction of load-bearing parts. Their filler is crushed stone of various fractions.
Heavy
The most commonly used types, as they are suitable for the installation of load-bearing elements (from 2,200 to 2,500 kg/m3). They include fractions of rocks (diabase, limestone, granite).
Particularly heavy
Their density (more than 2,500 kg/m3) determines the specific application. In the private sector they are practically not used, since they are used to build various structures special purpose (underground storage facilities, bunkers, dams, etc.). Fractions of “heavy” materials are used as filler (for example, cast iron shot, metal shavings, iron ore, barite).
By filler type
- Special, giving special properties artificial stone(heat resistance, resistance to radiation or low temperatures and a number of others).
- Porous (for example, lightweight concrete).
- Dense (heavy concrete).
By granule size
- Fine-grained (less used).
- Coarse grain (more common).
According to manufacturing technology
- Processed in autoclaves. They are considered the highest quality products, since the required characteristics of concrete are achieved by maintaining specified pressure and temperature during the entire hardening process (cellular concrete and some others).
- Natural hardening.
The same, but with the use of artificial heating.
By purpose
Special
These include materials that provide thermal insulation, resistance to critical temperatures, radiation exposure, and so on.
Structural
They are used to produce various reinforced concrete products, construct loaded parts of structures (for example, various floors, supports, foundations).
Hydraulic
Used to build dams, artificial reservoirs, underground tanks and a number of other objects.
What to look for when choosing a concrete class
1. Curing time. As the grade of concrete increases, it decreases. This should be taken into account if the product is not prepared at the pouring production site, but is delivered to the site by transport. In addition, it is determined by the conditions of use, because you will have to organize its installation. How will this be done - manually or using mechanisms and devices (gutter, concrete pump).
It is also important under what weather conditions the work is carried out. It is often necessary to organize insulation of the poured mortar in order to achieve its reliable “setting”.
2.Fraction sizes. It is clear that the larger they are, the more difficult it will be to mix the solution and compact the mass loaded into the form (formwork). You may have to organize vibropressing, and this is not always convenient or possible. In addition, there is the concept of “fluidity” of a solution. This must be taken into account if the formwork has a complex configuration, since you may have to spend time and effort “pulling” the concrete throughout the entire volume.
3. Availability of additives, how do they affect the characteristics of concrete? For foundations, such indicators as frost resistance and water repellency are especially important.
4. Strength of concrete. It largely depends on the brand of binder used to prepare the mixture.