Types of cellular concrete: classification, characteristics and production features

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Cellular concrete

Cellular concrete is the most popular material. Its distribution is associated with a large number of factors, including: physical and mechanical properties of the material, a wide variety of products made from it, availability of production and reasonable price.

The material is characterized by a fairly broad classification, which is determined mainly by the composition of the raw materials and the manufacturing method. So let's figure out what types of cellular concrete exist, how they differ from each other, and under the influence of what factors the properties and quality of products made from it can change.

What is the material

Cellular concrete belongs to the class of lightweight concrete and is distinguished mainly by the presence in its structure of pores that are filled with gas or air. There are a large number of varieties of this material, which we will now consider.

Pore ​​structure of cellular concrete products

Classification

Gradation occurs in accordance with the following characteristics and parameters, according to GOST 25485 89 cellular concrete:

According to the type of binder component, the following types are distinguished:

• Cement containing cement in an amount of at least 50%.
• Calcareous. They consist of boiling lime in an amount of up to 50% of the total mass. May also contain gypsum, cement or slag additives in amounts up to 15%.
• Mixed. They contain 15-50% cement, lime and slag.
• Ash , consisting of more than 50% ash.
• Slag containing, respectively, slag in an amount of at least 50%.

Depending on the hardening method, cellular concrete is:

• Autoclaved
• Non-autoclave.

In the first case, the material achieves hardening by exposing it to high temperature and pressure during processing in specialized equipment - an autoclave. This type of hardening is also called synthetic hardening.

In the second case, this process occurs naturally, under normal conditions, or by electrical heating. The method is called hydration hardening.

Cellular concrete can be characterized by different densities and, as a result, differ in scope.

Autoclaved and non-autoclaved cellular concrete block

Depending on the above factors, there are:

• Thermal insulating cellular concrete;
• Thermal insulation and structural;
• Structural.

Thermal insulation - used exclusively as insulation. It has a low density, less than 500, but at the same time, an excellent thermal conductivity coefficient. It is not used in the construction of walls, since its load-bearing capacity excludes the ability to withstand any loads except its own weight, which is also relatively small.

The second version of cellular concrete is much more durable, the numerical value varies from 500 to 900. It is used in the construction of walls and partitions. At the same time, its ability to retain heat, of course, decreases in accordance with the increase in density.

Structural cellular concrete is the most durable. Its density reaches 1000-1200 kg/m3. However, as it becomes clear, the thermal conductivity coefficient is also high. It is used in the construction of buildings up to 12 meters high as the construction of load-bearing structural elements.

House built using cellular concrete blocks

Also, depending on the porousization method, the following types are distinguished among cellular concrete:

• Foam concrete and foam silicates;
• Aerated cellular concrete and aerated silicate;
• Aerated concrete and gas silicates.

In addition to the above methods, other modified methods are also used in the production of cellular concrete.

These include:

• Combination of gas generation and aeration method. As a result, foamed aerated concrete is obtained;
• Swelling of a mass in a vacuum due to gas formation;
• Bubbling the mass with compressed air followed by a decrease in pressure.

In accordance with the type of silica component, cellular concrete is divided into:

• Natural sand;
• On the ashes;
• On other secondary siliceous industrial products.

What is cellular concrete, classification

Advantages and disadvantages

Like any material, cellular concrete is not without its pros and cons.

Let's look at the positive aspects first:

1. One of the most significant qualities is the thermal conductivity indicator. The material has a fairly high ability to maintain temperature, which significantly increases its value. This fact is easily explained: it’s all about the structure of the material, the pores of which contain air, which is a heat insulator. This characteristic is combined with sufficient strength.

As a result, the use of cellular concrete products in construction in the form of blocks will significantly reduce the cost of insulation, and in the future, heating costs. Soundproofing characteristics are also at a high level.

1. The material is safe for the environment and humans. It does not emit harmful substances into the atmosphere.
2. Products made from cellular concrete are easy to handle, which significantly increases the speed of construction and makes it possible to build structures with your own hands. In addition, the material is relatively light, which, in turn, reduces the load on the foundation when constructing walls using such blocks.
3. High seismic resistance of structures built from this material.
4. The combination of strength, density and weight leaves many building materials behind.
5. The ability to vapor permeate allows buildings built using cellular concrete to “breathe”. Thus, a favorable microclimate is established in the room.
6. Since the composition of cellular concrete is characterized by the presence of mineral components, the material does not rot or undergo other biological damage.
7. The durability of cellular concrete is high. According to the manufacturers, a house built from this material will last at least 50-60 years.

Despite the large number of advantages, cellular concrete also has disadvantages. Its use causes some difficulties and the material cannot be called universal.

Let us once again pay attention to the fact that cellular concrete is a porous material. This fact is both a plus and a minus.

The thing is that the products have high water absorption capacity. Accumulated moisture can crystallize during periods of predominance of negative temperatures, and cause irreparable damage to the structure of the cellular concrete product. In this regard, such buildings require technically correct finishing both outside and inside the building.

Products made from cellular concrete are fragile. Most often this occurs during transportation and during work, when mechanical stress is most likely.

However, these shortcomings can be completely mitigated. In the first case, through properly executed masonry, finishing and correctly selected materials, and in the second, through careful handling.

Note! Cellular concrete requires special treatment and care when using. Defects in cellular concrete that appear in finished structures are, for the most part, of the same type and are directly related to improper use, masonry, lack of reinforcement or finishing.

Defect caused by shrinkage of the house

Cracks in aerated concrete

Autoclaved cellular concrete

Most commonly used are products made from autoclaved cellular concrete, i.e., hardening by steaming under pressure (in autoclaves).

Autoclaved cellular concrete is made from the following mixtures:

• a) cement with quartz sand (compositions from 1: 1 to 1: 3); in this case, part of the sand is usually ground;
• b) ground quicklime with partially crushed quartz sand (compositions from 1: 3 to 1:5); such cellular concrete is called foam silicate or, accordingly, gas silicate;
• c) cement, lime and sand in various proportions.

The theory and methods for the production of autoclaved cellular concrete and reinforced products from them were developed by I. T. Kudryashev et al.

Volumetric weight of autoclaved cellular concrete in a dried to constant weight state, depending on its brand; in terms of compressive strength, should not exceed the following values:

Concrete grade ... 25 35 50 75 100 150 200

Volumetric weight, kg/m3. 600 700 800 900 1000 1100 1200

For non-autoclaved concrete, the specified volumetric weight values ​​for each brand of concrete are increased by 100 kg/m3.

The use of steaming under pressure (8 - 10 ati at 175-200 °) is based on the fact that under these conditions, lime introduced into the composition of cellular concrete (or lime released during the interaction of Portland cement with water) reacts with silica of sand, forming calcium hydrosilicates (mainly on the surface of sand grains). As a result, the strength and durability of autoclaved cellular concrete increase significantly.

To increase the surface of the sand grains, part of it is ground to the fineness of cement grains. The same goal can be achieved by using fine sand, or introducing into the mixture active siliceous materials (ashes from power plants, etc.), as well as ground granulated blast furnace slag. Some additives (ash, cement, ground blast furnace slag) increase the thermal resistance of cellular concrete ; Such concretes can be used for thermal insulation of hot surfaces with temperatures up to 700 - 800°.

Types of products made from cellular concrete

Products made from cellular concrete are presented in a wide range. They are actively used in the construction industry not only in Russia, but also in countries near and far abroad.

The market for cellular aerated concrete and foam concrete is growing every year, presenting consumers with an ever-increasing range of products. Let's consider what a developer can choose for himself among products made from this material?

List of materials

The following products are made from cellular concrete:

1. Floor slabs, covering slabs;
2. Large-sized blocks, reinforced and non-reinforced;
3. Small wall blocks;
4. Small thermal insulation products;
5. Sound-absorbing products;
6. Interior partitions;
7. Wall panels;
8. Tray and block lintels;
9. Thermal insulation backfill.

Monolithic cellular concrete, which has the property of hardening under natural conditions on a construction site, is used in the manufacture of:

1. Bases for underfloor heating;
2. Multi-layer and single-layer enclosing structures of buildings;
3. Thermal insulation layers of combined roofs.

Scheme: use of monolithic foam concrete

Hot cement concrete

I would like to highlight heat-resistant cellular concrete separately. During the operation and construction of thermal units, their use is necessary. This significantly saves materials and fuel.

And also: helps to create monolithic structures with increased thermal insulation ability, protect the structure (and/or unit) from high temperatures, create acceptable conditions for workers working in a hot shop, and much more.

Blocks made of cellular concrete: comparative characteristics and scope of application

The most popular products made from cellular concrete used in the construction of buildings are blocks. Their main types are: foam concrete and aerated concrete. The main difference between them is the manufacturing process itself and the method of creating pores.

• Cellular foam concrete is made using a special foaming agent. A solution consisting of cement, sand and water is moved into the mixer, where a foaming agent is added. As a result, the latter gives porosity to the products.
• Cellular aerated concrete is produced without the use of the above foaming component. Porosity is achieved through a chemical reaction of lime and aluminum powder, which is used as a blowing agent.
• Both types of blocks are quite actively used in the construction of buildings; the GOST for cellular concrete is also the same for both types. However, the palm still belongs to aerated concrete.
• Using the table, let's look at the main indicators of materials and figure out why foam concrete is losing to its competitor.

Table 1. Comparison of foam and aerated concrete:

As you can see, aerated concrete is the leader, but this does not mean that foam concrete is so bad. The advantage in price and thermal conductivity may well provide worthy competition.

It is also worth noting that foam concrete is more susceptible to shrinkage, although this indicator does not deviate from the technical documentation.

Note! Foam and aerated concrete also differ in their pore structure. In the first case they are closed, in the second they are open.

Foam concrete and aerated concrete comparison

Technical characteristics of cellular concrete

Cellular concrete belongs to the category of lightweight building materials. However, the method for producing it is not based on the addition of light aggregates, as, for example, in the production of slag concrete, but on the introduction of air bubbles.

The resulting light spongy mass is much lighter in weight and, most importantly, has excellent thermal insulation properties.

Method of obtaining

The technical characteristics of the material are influenced by the method of production.
Based on the production method, there are several types of concrete. Compared to each other, the strength of aerated concrete is higher.

However, the strength of any type of material can be increased by autoclaving.

Volumetric mass

For cellular concrete, such a characteristic as volumetric mass is important, that is, the weight of a unit volume is 1 cubic meter. m. According to this indicator, both foam and aerated concrete are divided into three categories:

Thermal insulation material is prepared without fillers. Other options may include fillers - usually fine or ground sand.

The weight of the structure is determined by the volumetric mass of concrete. It is not difficult to calculate it. On average 1 sq. m. wall weighs 300–450 kg if made of foam concrete, and 145–240 if made of aerated concrete.

In addition, both weight and strength are affected by the nature of the binder: silicate aerated concrete, for example, will be heavier with the same degree of porosity. But the water absorption of silicate options is higher. Therefore, their use compared to cement cellular concrete is limited.

Dimensions

The sizes of blocks made of cellular concrete (gas and foam concrete) differ markedly. Depending on the purpose, their dimensions can be as follows:

In addition, a variety of blocks of complex shapes are produced.

It is not difficult to make blocks of a different size from standard modules: cellular concrete is as easy to work with as wood and is perfectly connected with ordinary nails. Read below about the application and energy efficiency and other basic properties of cellular concrete, the weight of the blocks and their density.

Physico-mechanical, technical and other properties of products

Now, using the table, let’s look at the physical and mechanical indicators of the properties of cellular concrete, dictated by GOST 25485 89 cellular concrete technical conditions.

Table 2. Physical and mechanical properties of cellular concrete:

As can be seen from the table, autoclaved cellular concrete is superior to non-autoclaved concrete in its physical and mechanical properties. This is due to the special production technology.

Experts recommend giving preference to synthetic hardening cellular concrete. They are more durable, reliable, and a building constructed from such material will have the highest performance characteristics.

Now it’s worth taking a look at the physical and technical indicators for cellular concrete - GOST 25485-89 dictates that products must have the following numerical values.

Table 3. Physical and technical parameters of products made of cellular concrete:

• In accordance with these indicators, it becomes obvious that with increasing density, the thermal conductivity of cellular concrete, as well as its vapor permeability and sorption humidity also change.
• Separately, it is worth noting the shrinkage indicators of cellular concrete. They also directly depend on the density and type of cellular concrete.
• Thus, for autoclaved aerated concrete with a density of 600-1200, made from sand, the numerical value of shrinkage should not exceed 0.5 mm/m2 of area.
• For products whose silica component differs from the above, the maximum value is 0.7 mm/m2.
• Non-autoclaved aerated concrete, with a density of 600-1200, is allowed more - up to 3 mm/m2.

Note! Shrinkage of autoclaved cellular concrete with a density of up to 400 and non-autoclave concrete - up to 500, is not standardized by GOST.

Shrinkage, first of all, indicates the crack resistance of cellular concrete. The higher the indicator, the greater the likelihood of cracks appearing on the surface, which undoubtedly directly affects the durability and performance characteristics of the material.

Another important indicator established by the technical documentation is the release humidity.

Depending on the silica component, its value is:

1. 25% for sand-based products;
2. 35% for products based on ash and other secondary industrial products.

All of the above properties are subject to control in accordance with GOST, which also describes the basic acceptance rules.

Shrinkage and swelling

The shrinkage and swelling of cellular concrete is assessed using various methods, so the results of such studies are difficult to compare. According to domestic and foreign research, the shrinkage deformation of autoclaved cellular concrete made on the basis of cement (slag) and sand reaches 0.5-0.7 mm/m or more for concrete made on the basis of lime and ash, and non-autoclaved concrete 2 mm/m and more; swelling deformations depend on the storage conditions of cellular concrete and reach 0.4–1.6 mm/m.

As an example in Fig. Figure 18 shows graphs of changes in shrinkage of cellular concrete over time according to data from Soviet and Czechoslovak researchers [84]. In Fig. 19 [88] shows changes in shrinkage of cellular concrete over time according to Swedish researchers, and Fig. 20—swelling deformation during alternate wetting and drying of concrete [11].

As a rule, shrinkage deformations are established on prism samples measuring 40X40X160 mm.

Currently, a method has been developed for determining the shrinkage of cellular concrete using an indicator device of the NIIZhB design [25]. The magnitude of linear shrinkage is determined on three prisms measuring 40X40X160 mm, cut from the product to be tested. The sample is measured using the instrument shown in Fig. 21. The device consists of a stand, a bracket, a lower support with a cone-shaped protrusion and an indicator with a division value of 0.01 or 0.001 mm, which allows you to set the change in the length of the sample. The longitudinal axis of the sample during horizontal molding should be perpendicular to the direction of expansion of cellular concrete, and during vertical molding it should be parallel to the direction of the larger geometric axis of the product. Metal reference points are embedded in the middle of the end sides of the sample to secure it to the instrument. The samples are saturated with water by immersing them in a horizontal position to a depth of 5 mm. After three days, the samples are removed from the water, installed in the device, and a reading is made using the indicator, taking it as the initial one. The samples are then weighed and placed in a sealed container over anhydrous potassium carbonate (200 g) at a temperature of 20±2°C. They are kept under these conditions for 28 days. Every 7 days, check the length and weight of the samples, while simultaneously replacing the moistened potassium carbonate with dry one.

After determining linear shrinkage, the samples are dried to constant weight in order to determine their final and initial moisture content. After 28 days, linear changes are calculated for each prism using the formula

where εus is shrinkage in mm/m. Δl is the difference between the final and initial indicator indicators in mm, l is the length of the prism after 28 days, measured with a caliper, in m.

Shrinkage and moisture content are calculated as the arithmetic mean of the determination results of three samples; in this case, the initial and final moisture content of the prisms is taken into account.

Studies of the shrinkage of cellular concrete using this method have shown that the value of εus for different types of autoclaved cellular concrete varies from 0.1 to 1 mm/m and in some cases differs significantly from the value of εus determined using other methods.

Production technology and material testing methods

The production of cellular concrete is a rather labor-intensive process. And for each type there is its own special technology, which directly affects the quality indicators and characteristics of future products.

Manufacturing Features

As already mentioned, the manufacturing technology of various products is different, but the general principle is similar. For clarity, we will consider several options step by step. Let's start with the autoclave method.

The process occurs in the following order:

1. The ingredients are fed from dispensers into the concrete mixer: first, sand, then the missing water, the binder, additives in the form of gypsum and surfactants, and, lastly, the gas-forming agent. Aluminum powder is most often used.
2. To ensure the best reaction of the blowing agent and calcium hydroxide, the mixture of water and sludge is heated to 35%.
3. All components are thoroughly mixed.
4. Next, the mixture must be molded. There are 2 methods: injection molding and vibrocompression. In the first case, the process of gas formation occurs in a stationary form, using surfactants, changing temperature and water content. In the second - on a vibration platform.
5. After the gas release process is completed, excess mixture is removed, and the semi-finished product is cut to the desired size.
6. The next step will be processing the blocks in an autoclave.

The non-autoclave method is slightly different.

The production technology of non-autoclaved aerated concrete and foam concrete is extremely similar:

• First, prepare the solution by mixing all the components. Again, in the production of aerated concrete, mainly aluminum powder is added, and in the production of foam concrete - a foaming agent
• Next, the solution is sent to the molds. Setting occurs approximately after several days, after which the product is removed.
• Technical maturity of the block is subsequently expected to take about 28 days. At the same time, foam concrete products need constant moistening every 6-8 hours in the first 7 days, and later every 10-12.
• If equipment is available, the blocks are steamed in specialized chambers at a temperature of 70-80 degrees and a pressure of up to 0.7 MPa. This significantly speeds up the hardening process.

The production of monolithic aerated concrete is carried out using similar technology. After preparing the mixture, it is poured into formwork or other structures directly at the construction site.

The main disadvantage is the lack of control over the solution when used independently, and possible deviations from technical indicators. The video in this article will tell you more about the methods for producing various types of cellular concrete.

Testing

In accordance with GOST, there is a set of testing methods for products made of cellular concrete, with the help of which the quality of the output material is controlled and its compliance with established indicators. Let's take a closer look.

Table 4. Test methods for cellular concrete:

These tests are carried out at certain intervals, also established by GOST. Many of the indicators are contained in the passport of cellular concrete.

Cellular concrete testing

Physical properties of cellular concrete

The physical and mechanical characteristics of cellular concrete determine the area of ​​their expedient use in construction practice. When establishing the physical and mechanical properties of concrete, the GOST 12852-67 method is used [25].

To test cellular concrete, control samples are cut out or drilled from finished products or control unreinforced blocks: cubes, cylinders, prisms. If necessary, control blocks or full-size products can be tested [26–29].

Control samples are cut from products or blocks no closer than 2 cm from their edges. If the thickness of the product is less than 24 cm, control samples are taken only from the middle part.

The strength and deformation of cellular concrete under short-term and long-term loads are determined on prisms with dimensions 10X10X30; 15X15X60 and 20X20X80 cm, cut from unreinforced blocks or molded in metal forms. Prisms 10X10X30 cm, as well as control cubes with an edge of 10 cm, are dried to a constant weight before testing, and larger prisms are tested at natural humidity at an age of 28 days or more.

The resistance of cellular concrete to axial tension is determined by testing cubes or cylinders dried to constant weight, or special prisms or “eights”, and resistance to bending and shearing is determined, respectively, by testing beams and prisms of a special configuration.

Determination of concrete density in a batch

2.1. The volume and composition of the batch are established according to GOST 18105.

When determining the density of concrete structures using the radioisotope method, concrete from one batch of structures is included in the batch composition.

2.2. The density of concrete is determined on samples intended to determine the tempering strength in accordance with GOST 10180. The density is calculated based on the density of all samples of a series of concrete in a dry state.

2.3. When preparing a lightweight concrete mixture in accordance with GOST 7473, at least one series of samples is prepared in accordance with GOST 10180.

2.4. When monitoring the density of concrete in a batch using the radioisotope method according to GOST 17623, at least three structures are selected from each batch of structures.

The number and location of controlled sections must be indicated by the design organization in the working drawings of structures, depending on the geometric dimensions, purpose and manufacturing technology.

In the absence of instructions in the working drawings, controlled areas are installed by the manufacturer in agreement with the design or research organization.

2.5. The density of concrete in a batch is calculated using the formula

The unit value of concrete density is taken to be:

when checking by samples - the average density of all samples of one series according to GOST 12730.0;

when monitoring by radioisotope method - the average density of concrete of the structure, calculated as the arithmetic mean value of the density of concrete of the controlled sections of the structure.

Thermal insulating concrete: materials with increased ability to retain heat and their application

Insulating a wall with lightweight thermal insulating concrete
When talking about concrete, many people imagine something very heavy. And not everyone knows that there are different types of concrete mixture and products made from it with a wide range of applications in various fields of construction.

In this article we will talk about several types of lightweight concrete that are used as materials for insulating structures. Let’s figure out how during manufacturing a special structure and low weight are achieved while maintaining strength, albeit not high, and we’ll analyze the reasons for the popularity of such materials.

So, thermal insulating concrete: what is it and how is it used?

What determines the thermal insulation qualities of concrete products, and what are the general features of the materials?

Let's talk a little about the composition of the materials. Basically, cement acts as a binder. The filler can be different, and it determines the type of mixture.

As a rule, the higher the ratio of the latter compared to other components, the higher the thermal insulation qualities. The type of filler itself also affects the final result.

Below we will consider in detail the composition and properties of the most popular materials. The most important opponent of thermal insulation qualities is density and strength.

Products with increased values ​​have a high thermal conductivity coefficient. However, at the same time, their structural performance increases.

Let's look at the main general features of materials capable of heat preservation:

• As a rule, they are low in weight;
• Their frost resistance is not standardized by technical documentation;
• The density indicator does not exceed 400 kg/m3;
• It will not be possible to build anything constructive from them, since they cannot bear increased loads;
• Often, products are fragile and have low resistance to mechanical stress;
• Some technical characteristics, such as fire resistance and environmental friendliness, do not change and do not depend on the density of the materials;
• The products are capable of sound insulation and vapor permeation more than durable materials;
• Their prices are lower.

The concept of thermal insulation concrete, main types of materials

Now let's look at the main materials containing concrete that are suitable for thermal insulation.

Cellular concrete

The main feature of cellular concrete is the presence of a porous structure, which is achieved by introducing a gas or foaming agent into the solution. In the first case, aerated concrete is obtained, in the second - foam concrete.

Structure of cellular concrete, photo

The difference between them is the following:

• The formation of pores during the production of aerated concrete occurs through a chemical reaction between lime and aluminum paste or powder;
• The cellular structure of foam concrete is formed as a result of the addition of a blowing agent, which stimulates the swelling of the solution;
• Foam concrete has a closed pore structure, while aerated concrete has an open pore structure.

Both types of cellular concrete can have different average density values, which determine their purpose. Products suitable for thermal insulation are called thermal insulation; their density is 300-400 kg/m3.

Characteristics of cellular concrete of different densities

In order to obtain such material, it is necessary to control the ratio of components in the mixture. There should be more pores, and less cement in the composition.

Approximate proportions of raw materials for producing aerated concrete of different densities

A little about the features and types:

• Thermal insulating cellular concrete has become widespread due to its simplicity of production, ease of handling and high heat-retaining abilities.

Floor insulation with foam concrete
Note! It is also worth mentioning the existence of foamed aerated concrete. It is obtained by using two technologies simultaneously. Such material has not yet become widespread due to its relatively recent appearance on the construction industry market. However, in the future it can become an excellent heat insulator, since the emphasis in manufacturing is precisely on reducing the thermal conductivity coefficient.

• It's no secret that when producing products, it is possible that defective products may be produced; it is also not uncommon for products to break during transportation and storage. In this regard, manufacturers began to look for ways to recycle such materials in order to reduce losses.
• One of the options for successful recycling is the use of substandard aerated concrete. Aerated concrete crumbs are actively used in the creation of thermal insulation backfill, light plasters with increased thermal insulation qualities, floor screeds, bases for heated floors and in many other cases.

It is worth noting that thermal insulating cellular concrete can be made by hand. The process is quite simple, especially when it comes to blocks.

The instructions look something like this:

1. Knead the mixture;
2. The prepared solution is filled into the molds and waited until the swelling process is completed. The molds are filled approximately 1/3 to prevent overfilling of the mixture;
3. Excess is removed, semi-hardened products are stripped;
4. Finally, the blocks are subjected to heat and humidity treatment or simply laid to dry;
5. The products will be ready for use after 28 days.

If you produce it yourself, the final price of the material can be significantly reduced.

Polystyrene concrete

Polystyrene concrete is characterized by the presence of polystyrene concrete crumbs in its composition, which imparts lightness and gives the product increased heat-insulating qualities.

• The density of polystyrene concrete, as a rule, does not exceed 600 kg/m3. Thermal insulation products have an indicator of 150-400 kg/m3. At the same time, the specific heat capacity of concrete containing polystyrene is 0.05-0.17 W*mC, which is typical for products in a dry state.
• Polystyrene concrete is a leader among lightweight concrete in its ability to maintain temperature, therefore, for insulation, it is actively used not only in the form of blocks and slabs, but also in a liquid state.
• As in the case of cellular concrete, where the number of pores determines thermal conductivity, in polystyrene concrete the ratio of polystyrene chips in the composition to other components is responsible for this ability.

Characteristics of polystyrene concrete of different densities
The scope of application of products, and low-density materials in general, is quite wide:

1. Thermal floor screed;
2. Insulation of walls and ceilings;
3. Soundproofing and much more.

• Thermal insulation of concrete - or, more precisely, filling a reinforced concrete frame, or internal filling of walls built using well masonry technology, with this material is also possible.
• Opinions differ regarding the effectiveness of using high-density polystyrene concrete in the construction of walls, but opinions on thermal insulation using this material are unanimous.
• It is truly capable of maintaining temperature. And what’s more, its price is relatively low, which only attracts the attention of potential consumers.
• Making polystyrene concrete yourself at home is also possible. The principle remains the same: the mixture is placed in molds, waited for setting, the formwork is removed and sent to dry.

Making polystyrene concrete with your own hands

Arbolit

This material is more often called sawdust concrete. This is due to the presence of sawdust in the composition, which serves as a filler. In addition to the latter, this role can be played by: cotton, flax, rice straw or hemp.

Density depending on the type of filler

Thermal insulating concrete with wood chips has a thermal conductivity coefficient of 0.07-0.09 W*mS. And this is a worthy indicator. It is slightly higher than that of polystyrene concrete, but it is sufficient to provide a high degree of thermal insulation.

Thermal conductivity of wood concrete at different densities

Note! One of the main disadvantages of the material is its relatively uncompetitive price. The cost of the material is not budgetary, which is due to the necessary composition of the raw material and the lack of full competition due to its low prevalence. It is also worth noting that the heat transfer resistance of sawdust concrete remains a mystery to everyone. This is also a significant drawback.

Among the advantages it is worth highlighting:

• Fire resistance. Despite the presence of wood, cement mortar prevents combustion;
• The material is environmentally friendly and does not contain toxic or harmful substances;
• Durability and ease of handling;
• Well, we have already talked about thermal insulation characteristics.

You can also make wood concrete yourself. However, it is worth carefully calculating all costs and the level of savings, since the time investment will be significant.

The technology is similar to the production of polystyrene concrete products. The only difference is the need for preliminary thorough preparation and sorting of the wood component.

Wood concrete production process

Expanded clay concrete

The composition of expanded clay concrete includes cement, sand, water and filler. Most often, expanded clay of different fractions plays its role. It can also be shungizite, algoporite, slag gravel and other materials with similar properties.

Thermal insulating expanded clay concrete

Increased thermal insulation qualities are achieved by adding a coarse fraction to the expanded clay composition.

Firing provokes the formation of large pores, which ensures the following properties:

• Low thermal conductivity;
• Light weight of products;
• Reduced density and strength;
• Vapor permeability and sound insulation.

Thermal insulating expanded clay concrete has a thermal conductivity coefficient that is not as low as the materials described above; it is about 0.14 W*mS. This is due to the higher strength of the material. As a rule, the minimum value is 400 kg/m3 compared to 150 kg/m3 for polystyrene concrete; you must agree, the difference is significant.

However, this does not at all exclude the possibility of using expanded clay concrete as insulation. The most common area of ​​application is filling building envelopes.

Thermal block and thermal concrete panels

I would like to pay special attention to such products as heat blocks.

• They are not exclusively thermal insulating; houses and other structures are built from them.
• However, according to manufacturers, confirmed experimentally, such products are distinguished by a high ability to retain heat while maintaining decent strength and density indicators. This makes it possible to reduce the cost of insulating the structure.
• The presence of facing products allows you to avoid exterior finishing altogether.
• The products are a three-layer stone and consist of: a layer of expanded clay concrete, foamed polystyrene and artificial stone - a decorative layer.
• Due to the presence of EPS, which has a high thermal insulation ability, the wall thickness can be from 30 cm. This allows us to assert the leadership of this material among competitors.

And now a little about what thermal concrete is.

• This is an innovative composite material that appeared on the market relatively recently. It is used in the form of panels, which are made from a mixture of water, sand, cement and styrene granules. An armored belt is built inside, which increases the strength characteristics of the product.
• Thermal concrete is used in the construction of buildings and structures, and due to its high thermal insulation properties, intensive insulation of buildings is not required.
• The advantage is the accelerated pace of construction due to the large dimensions of the products.
• According to manufacturers, at the moment, thermal concrete is the warmest material of all existing ones.

The video in this article will tell you about the advantages and disadvantages of heat blocks.

Comparison of thermal insulating concretes with each other

Now let’s compare, using a table, the main technical characteristics of the above-described heat-insulating types of concrete. We will also analyze: the use of which of them will be most effective specifically for the purpose of thermal insulation.

The thermal conductivity values ​​of a heat block and warm concrete slabs vary depending on the manufacturer. And they mainly focus on the inverse value - resistance to heat transfer, which is about 3.2 m2 C/W for different wall designs.

Comparison of thermal conductivity of thermal insulating concrete and other wall materials

Finally

The range of types of concrete suitable for thermal insulation is quite wide.

It’s difficult to say for sure which material to choose. However, it is worth paying tribute to the less durable polystyrene concrete, which is more capable of maintaining temperature than others, and its price category is relatively low.

Thermal block and thermal concrete are new and quite expensive materials, so not every developer will decide to incur such costs. These materials have yet to prove that their price-quality ratio is quite reasonable.

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