Features of the structure and production of autoclaved aerated concrete. What is non-autoclaved aerated concrete, its properties and production? What does autoclave mean?

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Initially, the technology for creating aerated concrete provided for its production only in high-tech production. But over time, the demand for this material increased so much that autoclaved aerated concrete began to be used equally with a similar type of cellular material produced without additional heat and moisture treatment. And if an unprepared beginner dives into the abyss of a huge selection of aerated concrete, he can easily drown in the stream of information provided about it. So what is the difference between autoclaved aerated concrete and non-autoclaved aerated concrete and which one is best to buy? You will find answers to these pressing questions in our publication.

Aerated concrete production technology

Before talking about significant differences in the properties and quality of autoclaved aerated concrete and naturally cured blocks, let’s consider their component composition, which is absolutely identical:

additive-free Portland cement grades M300, M400, sometimes M500 is used;
clean sand of fine fractions - from 2.0 to 2.5 mm.
water of medium hardness without chemical impurities;
gas generator - aluminum powder or paste;
a substance that triggers chemical swelling reactions - lime, the type, condition and dispersion of which depends on the production method;
modifiers that improve the quality of the final product are added at will and are not mandatory components.

Another similarity that unites autoclaved and non-autoclaved aerated concrete is the principle of mortar production.

At the first stage, in accordance with the technology, an ordinary cement-sand mortar of the required consistency is prepared. The resulting mixture is distributed over the formwork. After which aluminum powder and lime are introduced into it. It is the reaction of these components that ensures the formation of gas; the solution swells, forming pores.

Further technologies diverge at the stage of curing and processing of aerated concrete. During natural hardening, the finished solution is poured into the formwork, forming blocks the right size. After gaining strength, the products are stripped and sent to the warehouse finished products.

When using an autoclave for aerated concrete, this stage is a little more complicated. Namely, the mixture is poured into monolithic formwork. After swelling and gaining minimum strength, the aerated concrete block is cut into products of the required sizes and sent for additional firing in an autoclave, where the temperature is maintained at 200 0 C and a pressure of 10 Bar. Such conditions activate cement hydration processes to the maximum and allow excess moisture to be removed from concrete.

As a result, it turns out that the products natural drying- this is just a hardened expanded cement-sand mixture, when autoclaved aerated blocks during the firing process form a new synthetic component - tobermorite, which qualitatively improves the characteristics of the final product.

Properties of non-autoclaved and autoclaved aerated concrete

The resulting blocks, manufactured in two different technologies so different both in appearance and in their characteristics that even an inexperienced layman can distinguish them from each other.

External indicators

The first thing the buyer encounters when choosing is the appearance of the materials. It would seem that it makes no difference what they look like wall blocks, which subsequently still need to be plastered. However appearance– the most accurate visual characteristic that will help weed out low-quality products.

Geometric dimensions

If we compare gas blocks based on geometry, then autoclave-cured products are more accurate. This is partly due to autoclaving and, of course, cutting technology. Even GOSTs regulate deviations linear dimensions from nominal in different ways, depending on the production method used.

These data only highlight the fact that autoclaved aerated concrete has precise geometry finished products, which prevents:

freezing of walls due to thickening of the masonry joint, which compensates for deficiencies in the shape of the blocks;
overconsumption of masonry adhesive, leading to increased costs.

Color

When purchasing blocks, pay attention to their color. Of course, it will be gray in the case of naturally hardening products and almost white in autoclaved aerated concrete. Differences in block shades and color heterogeneity indicate changes in production process, which often lead to reduced performance.

Automated equipment for the production of autoclaved aerated concrete reduces any errors to zero, which is initially considered a guarantee of quality and durability. In addition, such large-scale workshops are complemented by their own construction laboratory, in which timely testing is carried out to identify inconsistencies in technology or recipes.

Physical and mechanical properties

Aerated concrete blocks differ not only in external characteristics and color, but also in physical and mechanical properties.

Strength

Aerated concrete is represented by a wide range of strength grades - from B1 to B7.5. They are widely used not only to create load-bearing structures, but also to insulate walls. If we compare aerated concrete produced using different technologies, autoclave concrete is more durable at the same density as non-autoclave concrete.

For example, blocks with a density of D600 must have a strength class of B3.5. If for autoclaved products the indicator is met, then with naturally seasoned products the strength class hardly reaches half the norm. The situation is even worse with the strength indicators of aerated concrete produced by hand. If you want to see this for yourself, buy a block and have it tested by an independent construction laboratory. The results will be obvious.

Thermal conductivity

The thermal conductivity of aerated concrete directly depends on the density of this material. The lower the density grade of the block, the better its heat capacity properties. It makes more sense to purchase products of lower density, but with higher strength characteristics, thereby reducing the thermal conductivity of the walls.

Shrinkage

The weakest side of any cellular concrete is its shrinkage after the walls are erected. If the wrong construction technique is used, cracks may appear and the plaster layer may peel off. The shrinkage processes of naturally aged aerated concrete can last up to several years, when autoclaved blocks are practically free of such a drawback, since during heat and humidity treatment they have already achieved brand strength and complete drying.

In addition, seasoned aerated concrete blocks under natural conditions are far from ideal, which negatively manifests itself in the form of shrinkage. This not only leads to a violation of linear dimensions, but also to the destruction of the structure.

To summarize, we can easily conclude that autoclaved aerated concrete blocks have undeniable advantages over naturally cured products. But in any case, when purchasing such wall material, always ask for documents certifying its quality.

Comments:

Autoclaved aerated concrete is a prominent representative of porous concrete and has proven itself quite well in many countries around the world. Such materials have now been found wide application in the construction of residential and industrial facilities.

The main components of autoclaved aerated concrete: cement, quartz sand and special gas generators.

Currently, many companies are engaged in the production and sale of the material. Autoclaved aerated concrete on the market building materials presented in a wide range: different shapes, sizes and colors. One thing is constant - high performance characteristics, which distinguish it favorably from other products.

Material structure

Aerated concrete is a type of cellular concrete in which air pores measuring 1-3 mm are located throughout the entire volume. Its basis is concrete mixture from a binder, filler and water.

In general, the class of aerated concrete includes (divided by type of binder composition) cement-based aerated concrete, gas silicate concrete with lime as a binder, slag-based aerated concrete and gas gypsum. Like autoclaved aerated concrete, the most widely used material is cement-based with the addition of lime.

Air pores in the structure are created due to chemical reaction with the release of gas. To initiate this reaction, aluminum powder or paste is added to the mixture. Thus, the composition of aerated concrete, in general, is a mixture of cement, lime, sand, water and aluminum powder residues. If necessary, additives can be added to impart specific properties. Accordingly, the structure autoclaved concrete- a hardened concrete mass with numerous small pores evenly distributed throughout the volume.

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Manufacturing Features

Autoclaved aerated concrete gets its name from the method of hardening the concrete mass after a chemical reaction with the release of gas. A diagram of the complete material production cycle is shown in Fig. 1.

The production of such aerated concrete is carried out in an autoclave in the following order. The concrete mixture is mixed to the consistency of sour cream and poured into molds to half the volume, while a shock load is applied to the mixture, during which the process of slaking lime occurs with the release of heat. Since all this happens in an autoclave, the temperature rises to 80 degrees.

Figure 1. Scheme of the full production cycle of autoclaved aerated concrete.

An active reaction of aluminum and lime begins with the release of hydrogen. The concrete mass increases in volume and fills the entire form. Pressure rises in the autoclave. Under the influence of temperature and pressure, cement hardens, clogging the pores inside its volume. During the reaction, air displaces hydrogen from the pores, filling them. In this way, a concrete structure is formed in which air pores occupy up to 80% of the total volume. By changing the mode and amount of introduced aluminum powder, the pore concentration can be changed over a wide range.

Autoclave hardening of the mass is carried out within 1-2 hours. Then the lid of the autoclave is removed and the aerated concrete is cut into blocks of the required size, while complete hardening of the concrete is not yet achieved. When cutting, the end elements of block engagement are formed (if necessary). After cutting, the blocks are again placed in an autoclave, where they are moistened at a temperature of about 190 degrees and a pressure of up to 1.2 MPa. Under this influence, the mass finally crystallizes to form a durable mineral. Final hardening and crystallization occur within 12 hours. Typically, the concrete mixture is prepared in the following proportion: cement (usually Portland cement) - 20%, quartz sand - 60%, lime - up to 20%. Aluminum residues - no more than 1%.

The main advantage of the autoclave hardening method is that when exposed to high temperature and pressure cellular aerated concrete forms a special mineral formation - tobermorite, which has an increased mechanical strength and is not subject to shrinkage. In addition, such artificial conditions significantly accelerate the hardening process of the mass, which is very important in industrial production.

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Basic properties of the material

Due to its porous structure, aerated concrete has a low specific gravity (from 300 to 700 kg/m³) and high thermal insulation properties. The autoclave production method also provides high compressive strength, up to 50 kg/cm².

By varying the pore volume, the density of aerated concrete changes; At the same time, strength and thermal conductivity change. At the same time, changes in the main parameters occur in different directions. A decrease in density (increase in porosity) leads to an increase in thermal insulation properties and a decrease in strength, and an increase in density leads to the opposite effect.

Based on this dependence, autoclaved aerated concrete is divided into 3 categories: thermal insulation, structural and structural-thermal insulation. Autoclaved concrete with a density of up to 400 kg/m³ is a thermal insulation type and is intended for private low-rise houses in areas with a fairly cold climate. Aerated concrete with a density of 700 kg/m³ is structural and is used in load-bearing structures and houses with several floors, but it will have to be additionally covered with thermal insulation. Structural and thermal insulating concrete with a density of 500 kg/m³ has optimal properties, which, with sufficiently high strength, provide good thermal insulation.

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What are the block sizes?

The low weight of porous concrete makes it possible to use building elements with increased dimensions. Building blocks made of aerated concrete have a length of 625 mm, a height of 200 and 250 mm, and a width of 100-400 mm. Such dimensions make it possible to significantly speed up and simplify the laying of walls, while the weight of the block remains within reasonable limits for its manual movement and laying.

An important advantage of autoclaved concrete is the accuracy and stability of the geometry of building elements (blocks). Autoclave curing of the concrete mass in the mold allows for clearly defined edges and corners, even smooth surfaces of the edges, very high dimensional stability, which remain almost unchanged over a long production time. If you take blocks from different production batches, then deviation is only possible within 1.5 mm in all directions (first category of accuracy) or up to 3 mm for the third category. Very strict standards have also been established for the stability of ribs and corners.

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Other properties of aerated concrete

Autoclaved aerated concrete has high vapor permeability. In terms of its breathability, it belongs to “breathable” building materials, i.e. capable of removing steam from the room to the outside. This property prevents the formation of mold or fungi in areas of steam condensation.

The porous structure provides increased sound insulation properties.

The material will gain wide popularity in Europe due to its environmental friendliness. The composition of aerated concrete does not contain any harmful impurities (even aluminum is found in small quantities and in a bound state), which eliminates harmful emissions both during construction and during operation. The environmental friendliness of the composition is not disrupted even by exposure to high temperatures and other climatic factors. In its own way fire safety and fire resistance, aerated concrete can be considered unique. Even long-term exposure open flame and thermal load does not ignite or destroy the material.

Currently, the demand for building blocks made from cellular concrete and you can often hear the question: “what is the difference between autoclaved and non-autoclaved aerated concrete?” This article will discuss the main differences and performance indicators of these products.

Material characteristics

First, we need to clarify the terminology. Cellular concrete refers to all lightweight concrete, during the manufacturing process of which cells (pores) are formed in the structure. In turn, it is divided into foam concrete and aerated concrete, depending on the technology for creating pores. The next stage of division occurs depending on the hardening process - autoclave or non-autoclave.

Autoclaving

When steaming the mixture necessary for the production of aerated concrete at a pressure above 12 atmospheric and a temperature above 190 degrees Celsius in devices called autoclaves, new material with characteristics that cannot be obtained under normal conditions - this process is called autoclaving. As a result, the structure of concrete changes at the molecular level and a new material with completely unique characteristics is obtained, called tobermorite.

Non-autoclaved concrete is concrete that has hardened naturally or with the use of steam, but under normal atmospheric pressure a mortar with pores, while autoclaved aerated concrete is an artificially created stone. They are fundamentally different in many respects. They have different compositions and different physical and technical parameters, which are an order of magnitude higher for autoclaved aerated concrete.

Main characteristics of materials:

Quality

The quality of autoclaved aerated concrete is always beyond any doubt, since its production is an extremely complex technological process that is impossible to implement in home-made conditions. During production, it is necessary to simultaneously control many processes and parameters; for this, in modern factories the degree of automation reaches 95 percent and practically eliminates the possibility of non-compliance with technology due to human fault. Manufacturing, as a rule, takes place in large factories and the material is brought to the construction site in the form of finished building blocks. The technology is described in modern GOST from 2007 and must be confirmed by test reports and product certificates. For the production of foam blocks and aerated concrete, such capacities are not required and at first glance this seems to be a plus. After all, the products are cheaper. But can you eliminate the risk of poor-quality production or even handicraft? When purchasing autoclaved aerated concrete, this question will not arise, because you can always be 100% sure of its quality.

Uniformity

Non-autoclaved aerated concrete is produced by adding a gas-forming agent to the concrete mass and mixing it. As a result, there are cases in which the bubbles, having less weight, float up, and the fillers, on the contrary, settle at the bottom. As a result, the finished product in the form of building blocks is heterogeneous and may even have various parameters. In the case of the production of autoclaved aerated concrete, everything is completely different. The process of gas formation and hardening occurs simultaneously and proceeds uniformly throughout the entire volume of the produced material. As a result, the pores in the finished material are distributed evenly and after completing the stage of cutting the finished material into building blocks, they are of ideal quality and uniform structure.

Fastenings

Since aerated concrete is very durable, it is possible to secure heavy materials and equipment on it. For example, ventilated facades made not only of lightweight materials, but also heavy ones of porcelain stoneware. To ensure reliable fastening, use anchor bolts with polyamide expansion elements. As a result, when using, for example, a 10x100 anchor, an axial pullout load of up to 700 kg is maintained, which is very close to the values of a solid brick.

Shrinkage

As it gains strength, significant shrinkage of non-autoclaved aerated concrete occurs, as a result of which cracks appear in the finished masonry, plaster falls off, or the finishing layer peels off. All this lasts for 3-5 years until the material reaches its strength. Often, when using such materials, walls cannot simply be puttied and painted; as a rule, more complex work is required. The inside has to be finished with plasterboard, and the outside has to be used with brick or curtain facades. Such problems do not arise when using autoclaved aerated concrete, since it gains its strength during the production process. For comparison, the shrinkage rate of autoclaved aerated concrete is 0.5 mm/m, but that of non-autoclaved aerated concrete is from 1 to 3 mm/m.

Precision production

During the production process for not autoclave materials are based on the permissible values from the old GOST; as a result, the finished building blocks have a big difference in geometric characteristics. For autoclaved aerated concrete blocks, such problems do not exist, since all production is carried out in accordance with modern GOST and the differences in the parameters of the finished product are minimal. Due to the large error in geometric dimensions, a number of problems arise when using non-autoclaved aerated concrete:

Increases required amount mortar and, as a consequence, the cost of construction.
Cold bridges form due to thick seams.
Leveling the surface of the walls becomes a rather labor-intensive process.

Thermal insulation

The level of thermal insulation of both materials is very good. But we can consider this issue from the point of view of efficiency of use different materials and costs to achieve the same effect. The level of thermal insulation, among others, is influenced by such an indicator as the density of the material. The higher the density level, the more low performance The building blocks will have thermal insulation. For example, for using the material as a constructive material, and even more so for load-bearing walls, high strength is required. To achieve the desired performance using non-autoclaved aerated concrete, a density of at least 700 kg/m3 is required. This means that for high-quality thermal insulation, the wall thickness should be about 65 cm. Under the same conditions, to achieve the required level of strength, you can use autoclaved aerated concrete with a density level of 500 kg/m3 and the wall thickness will be about 40 cm.

Results

At first glance, when building houses, it seems obvious that the price advantage is not in favor of autoclaved aerated concrete. But in the end, taking into account all the shortcomings of non-autoclave materials and the amount required to eliminate them, this plus comes to naught. Autoclaved aerated concrete is superior to non-autoclaved aerated concrete in almost all respects.

Autoclaved aerated concrete – artificial material, well proven in the construction of industrial and residential buildings. It is a type of cellular concrete. Since the material is becoming increasingly popular in the construction of private buildings, you should know what its characteristics are, what autoclaving is, the differences between autoclaved concrete and non-autoclaved concrete, their pros and cons.

Figure 1. Autoclaved aerated concrete

Autoclaving ensures accelerated hardening of concrete. The difference between the building material and its analogues is its higher strength.

Autoclaving is a steaming process under high temperature conditions. environment And high pressure. It flows in special metal capsules. When the finished blocks are loaded into the autoclave, the pressure is 0.8-1.3 MPa, and the temperature rises to 175 0 –191 0 C. It takes approximately 12 hours until complete hardening.

Autoclaved aerated concrete undergoes changes at the molecular level. As a result of processing, a new mineral, tobermorite, is formed. He has unique properties. main feature The difference between autoclaved concrete and non-autoclaved concrete is that the first is an artificially produced stone, and the second is a hardened sand-cement mortar.

Autoclaved aerated concrete blocks have special characteristics: composition, operational features, physical and technical parameters. In most respects, autoclaved and non-autoclaved concrete are different.

Features of masonry of autoclaved aerated concrete

When erecting buildings from material produced using an autoclave for aerated concrete, you need to know a few general rules masonry and have an idea about the features of working with aerated concrete blocks:

To begin with, the tubs always choose the most protruding corner. This will be the place with the minimum layer thickness.
The first row is laid using cement-sand mortar.
Then aerated concrete blocks are distributed to the remaining corners. When performing masonry, they act as landmarks. A cord is pulled between them.
In cases where the length of the wall exceeds 10 meters, several additional ones are installed between the corner reference blocks.
The initial row is laid out completely. If gaps arise during work, the blocks are cut to the required size using an electric saw or hacksaw.

After a short break (2-3 hours), the first row is reinforced.
When laying the remaining rows, glue is used mainly. It is applied with a trowel and leveled with a comb. The seams are shifted by 20%.
Since the glue sets quickly, it is recommended to level aerated concrete blocks as quickly as possible. It is almost impossible to correct shortcomings.

Pros and cons of materials

Autoclave curing blocks in comparison with non-autoclaved concrete have a number of advantages:

Strength. On walls made of autoclaved aerated concrete, it is allowed to mount shelves, cabinets, as well as objects that have a large mass. For example, air conditioners. Cellular concrete that has not been processed in an autoclave cannot withstand such loads.
High quality. Since autoclaved aerated concrete can only be produced in industrial conditions, in terms of quality it compares favorably with non-autoclaved analogues, which are often produced using artisanal methods.
Less shrinkage during use. The amount of shrinkage directly depends on the strength of the building material. The average value for autoclaved aerated concrete is 0.5 mm/m, for non-autoclaved aerated concrete – up to 3 mm/m.

The pros and cons of autoclaved aerated concrete are presented in the table:

Advantages	Flaws
Strength.	Absorption of moisture, which in conditions low temperatures destroys the structure of autoclaved aerated concrete.
Eco-friendly, safe for the environment.	Problems with fixing fasteners, the need to use specialized products for aerated concrete.
Fire resistance.	Fragility, which is often revealed already at the transportation stage.
Easy to cut and sand.
Vapor permeability, providing a comfortable microclimate.
Thermal conductivity, which ensures heat retention in buildings.
Frost resistance, allowing to withstand up to 150 cycles of freezing and thawing.
Resistant to mold and rot.

Overview of the main qualities of the material

Figure 2. Autoclaved aerated concrete

Taking into account the advantages and disadvantages of autoclaved aerated concrete blocks, we can highlight the main properties:

Strength. Autoclaved aerated concrete has the following characteristics: density up to 800 kg/m 3, compressive strength class B2.5-B3.5.
Stability of quality, which is regulated by GOST, adopted in 2007. Products manufactured at industrial enterprises, are accompanied by quality certificates.
Uniformity of the material. Its difference is that during production the processes of gas formation and hardening occur simultaneously throughout the entire volume of raw materials. Ready-made aerated concrete blocks have pores of the same size and do not have air pockets.
Eco-friendly, breathable. Buildings made of autoclaved aerated concrete blocks maintain a microclimate similar to the climate wooden log house. In production, mineral raw materials are used that are resistant to mold, mildew, and decay.
Shrinkage. Aerated concrete blocks are not subject to shrinkage deformations, since they gain sufficient strength during production and autoclave processing.
Accuracy of geometric dimensions. This indicator is determined by GOST. Deviations should not exceed 2 mm in width, 3 mm in length and 1 mm in thickness. When producing aerated concrete building materials, they resort to cutting large quantities. This allows you to withstand required dimensions blocks with high accuracy, which ultimately improves the quality of the masonry.

Aerated concrete production technology

The technological process includes the following stages:

Combination of water and sand with particle grinding.
Introduction of lime, cement and table salt. Mixing of raw materials.
Pouring the resulting solution into the formwork.
A hydrogen reaction that releases gas, which creates a porous structure.
Hardening of the mass within 2-3 hours.
Cutting into blocks using industrial strings.
Autoclaving of aerated concrete.

Areas of use

The scope of application of autoclaved aerated concrete is not limited to the construction of industrial buildings. The material is used for the construction of residential buildings.

The blocks are suitable for laying single-layer or double-layer external walls. Partitions for fireproof rooms are made from them.

Other areas of use:

construction of floor slabs in buildings;
production wall panels for industrial and residential buildings.

The demand for autoclaved aerated concrete is so high that the manufacturers of this material have united into a national association, which is designed to discuss the prospects for the development of the industry and develop new requirements for quality and innovative approaches to the organization of production.

Due to the increased interest in aerated concrete blocks, many are interested in the difference between aerated concrete and autoclaved aerated concrete. And although new material is obtained from the same components, there are differences in the use of the material, quality, strength and density of the block. Depending on the hardening conditions, autoclaved and non-autoclaved aerated concrete differ in performance characteristics. Non-autoclave products are characterized by greater shrinkage, while autoclave products are characterized by dimensional stability.

The difference between autoclaved aerated concrete and non-autoclaved aerated concrete in terms of production technology and application

Despite the popularity of aerated concrete products, not everyone knows how autoclaved and non-autoclaved aerated concrete is produced. Many people not involved in the construction industry associate cellular concrete with non-autoclave technology. However, aerated concrete products are also produced using the autoclave method. Depending on the chosen production method, it varies necessary equipment for making and hardening blocks.

The performance characteristics differ between autoclaved and non-autoclaved aerated concrete.

Aerated concrete composites, depending on the method of hardening, are divided into the following varieties:

Autoclave materials

Portland cement mixed with quartz sand, lime and water. Aluminum powder is introduced into the working mixture, which, interacting with lime, promotes the formation of air pores.

During the gas-forming reaction, the volume increases due to the uniform formation inside the aerated concrete mass of many round pores with a diameter of no more than 3 mm. After the molds are filled, the products are placed in autoclave chambers. At temperatures exceeding 200 degrees Celsius and a pressure of 10-12 atmospheres, the material hardens, acquiring working properties;

Non-autoclave products

It is made from the same components as autoclave blocks. When producing aerated concrete using the non-autoclave method, there is no need to use autoclaves. Simple technology allows the production of aerated concrete in small enterprises or on a construction site.

After preparing the working solution, the molding containers are filled. Aerated concrete mixture hardens under natural conditions. By reducing the energy intensity of production, the cost of non-autoclave units is significantly reduced. However, at ambient temperatures, the drying time increases to a month.

Features of manufacturing technology affect the structure and properties of the material. Autoclave blocks with cells evenly distributed inside the array, they have increased strength. Non-autoclaved products also have a porous structure, but the air cavities are unevenly located inside the blocks. This negatively affects strength.

The structure and properties of the material are influenced by the manufacturing technology

The use of non-autoclaved and autoclaved aerated concrete is different:

from blocks obtained using autoclave technology, they build residential buildings various number of storeys, cottages and dachas;
non-autoclave material is used for construction utility rooms and technical objects.

The strength of buildings built from non-autoclaved aerated concrete is lower than that of buildings made from autoclaved building materials. Various technology production, which determines the performance characteristics of the material - the main difference between autoclaved aerated concrete and non-autoclaved aerated concrete.

Basic properties of non-autoclaved and autoclaved aerated concrete

Let's consider the properties of heat-treated and naturally hardened aerated concrete. Main characteristics of materials:

increased thermal insulation properties. Thanks to the air cells located inside the aerated concrete mass, the material retains heat well. The energy-saving properties of gas blocks make it possible to maintain a favorable temperature in the building all year round, as well as reduce the amount of space heating costs;
soundproofing characteristics. Aerated concrete walls make it difficult for street noise to penetrate into living spaces. Effective noise insulation is ensured by saturating the array with air pores that absorb extraneous sounds. Sound-absorbing properties provide comfortable conditions for accommodation;

The material retains heat well thanks to the air cells located inside the aerated concrete mass.

resistance to negative temperatures. The frost resistance of aerated concrete depends on the concentration of moisture accumulating inside the air cells. Under the influence of negative temperatures, the liquid crystallizes and, increasing its volume, tries to destroy the gas block. Plastering the surface of the blocks increases frost resistance;
light weight. Block aerated concrete, characterized by reduced weight and increased volume, is quickly erected different kinds buildings. To transport lightweight gas blocks, vehicles with increased carrying capacity are not required. Products for masonry are supplied manually, and aerated concrete walls do not place increased load on the foundation;
machinability. There is no need to use special equipment to change the size of aerated blocks during masonry. The material is easily cut with a hand saw or grinder. If necessary, perform inside aerated concrete block holes or cavities, this operation can be easily performed using an electric drill.

Aerated concrete blocks are also characterized by:

correct form;
exact dimensions;
rough surface;
environmental cleanliness;
fire safety;
at an affordable price.

When planning to build the frame of your own house or cottage from aerated concrete blocks, you should choose the right material and understand how autoclaved aerated concrete differs from non-autoclaved aerated concrete. Let us dwell on this point in more detail and compare the properties of materials produced using different technologies.

The frost resistance of aerated concrete depends on the concentration of moisture accumulating inside the air cells.

The difference between aerated concrete and autoclaved aerated concrete in terms of technical characteristics

For the construction of buildings, autoclaved and non-autoclaved aerated concrete is used. What is better to use for the construction of a specific structure? To answer this question, you need to compare the characteristics.

Autoclaved and non-autoclaved aerated concrete – which is better in quality

Technology plays a decisive role in product quality:

autoclave materials are produced in industrial conditions using modern technological equipment with an increased degree of automation. Influence human factor in the production process is reduced to a minimum. Quality control is carried out in special laboratories;
non-autoclaved aerated concrete is produced using a simplified technology that does not require special equipment. Using a concrete mixer, formwork and auxiliary workers, it is not difficult to produce blocks in a makeshift manner. Under such manufacturing conditions, it is difficult to talk about the stability of product quality.

When thinking about the durability of a future structure, give preference to industrial products manufactured in accordance with the requirements of the current standard.

Differences in aerated concrete strength

The strength properties of aerated concrete are related to its density. With equal specific gravity The load capacity of autoclaved concrete and non-autoclaved composite differs significantly:

Hand saw or a grinder can easily cut material

thermal insulating aerated concrete with a specific gravity of 0.4 t/m3, produced by the autoclave method, has a strength class of up to B2.5;
a similar material that has undergone hardening at natural temperature and pressure has a strength class reduced to B0.75.

The popular D600 gas block, steamed in autoclaves, has a compressive strength of B3.5. The strength of the same block made using a non-autoclave method is B2. The heterogeneity of the structure of handicraft blocks negatively affects their strength.

Shrinkage of non-autoclaved and autoclaved building materials

Aerated concrete blocks have different shrinkage. For this indicator, the value is regulated by the standard:

shrinkage of autoclaved materials per meter of masonry does not exceed 0.5 mm;
the same figure for non-autoclave blocks reaches 3 mm.

To prevent cracking of the walls, you should use a reinforcing mesh and plaster the surface of the aerated concrete.

How does the technology for creating aerated concrete affect the porous structure?

Depending on the production method, the homogeneity of aerated concrete changes:

air cavities in autoclave products are evenly distributed throughout the volume;
the cells inside non-autoclave blocks are concentrated near the outer surface.

Making non-autoclaved aerated concrete without compacting the material causes unevenness in the structure, which negatively affects performance.

The uniformity of aerated concrete varies depending on the production method

Precision of block production

Aerated concrete products manufactured various methods, are distinguished by geometric accuracy and dimensional stability:

thanks to the use of precision equipment for the production of autoclave products, the error of the blocks does not exceed 1 mm;
use of inexpensive equipment and different forms for the manufacture of non-autoclaved blocks increases the dimensional tolerance to 5 mm.

With stable dimensions and precise tolerances, the consumption of glue is reduced, which can be laid in a layer of 1-2 mm.

Comparing the properties of materials based on thermal conductivity

Both types of aerated concrete have increased thermal insulation characteristics, however there are certain differences:

autoclaved aerated concrete provides thermal protection with reduced product thickness;
To ensure thermal insulation of a building made of non-autoclaved blocks, increased wall thickness is required.

Autoclave blocks are superior to non-autoclave building materials in terms of thermal insulation properties.

We compare the frost resistance of aerated concrete blocks

The durability of buildings depends on the frost resistance of the blocks:

walls built from non-autoclaved aerated concrete can withstand no more than 50 freezing cycles;
structures made from autoclaved gas blocks are not subject to destruction over 100 cycles.

When choosing a material for a residential building, it is important to consider its frost resistance.

We evaluate the fire resistance of aerated concrete

Both types of aerated concrete are equally fireproof. When the material is heated, no toxic substances are released. Aerated concrete is used for the construction of fire-resistant structures where there is a high probability of exposure to elevated temperatures.

Conclusion

Having analyzed the difference between autoclaved aerated concrete and non-autoclaved one, it is easy to choose a building material for the solution specific tasks. It is important to comprehensively evaluate the properties of the material. It is preferable to use high-quality aerated concrete, which is characterized by increased strength.

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