Refers to artificial building materials. It has a porous structure and is highly popular in the construction of residential and industrial buildings. Depending on the production method, aerated concrete is divided into autoclave and non-autoclave. This article will help you understand production technology autoclaved aerated concrete, its advantages and disadvantages.

Compound

Autoclaved aerated concrete is produced by burning blocks in special autoclave ovens, where they are subjected to high pressure up to 12 atm. and a temperature of 191 °C. This allows not only to speed up the curing process of the material, but also to obtain a material with improved strength characteristics compared to conventional non-autoclaved blocks. During the firing process, the molecular structure of the material changes and the result is aerated concrete, reminiscent of the volcanic rock Tobermorite.

Autoclaved aerated concrete is produced by burning the material in special ovens in which it is exposed to high pressure and temperature

Aerated concrete obtained by autoclave firing is often called gas silicate. Its composition includes:

1. Portland cement.
2. Quartz sand.
3. Lime.
4. Aluminum powder.
5. Gypsum.
6. Water.

When producing gas silicate, the exact proportions of these materials are observed. Gypsum is added so that the mass does not immediately thicken, and aluminum powder helps the process of forming many bubbles.

Advantages of the material

Convenient dimensions of autoclave hardening make work easier. They allow you to lay building elements faster than laying conventional bricks. Gas silicate meets the standards fire safety, since it does not highlight harmful substances during combustion and does not ignite quickly.

Aerated concrete blocks are resistant to harmful microorganisms and mold, as they are made from mineral raw materials

Aerated concrete - pros and cons

Advantages

1. High thermal insulation performance. Houses made of gas silicate blocks reliably retain heat. With their help, owners can save significantly on additional heating.
2. Light weight blocks. This makes it easier to work with the material and reduces the load on the base of the building.
3. High sound insulation material. Is good advantage when choosing an apartment in a multi-storey building.

Flaws

1. Poor compressive and tensile strength. During construction, it is used, which reduces the likelihood of cracks forming in the walls of the building.
2. High cost of blocks. Gas silicate is practically not produced in small industries due to the need for autoclave ovens. Large production involves the production of high-quality products and compliance with production standards, but you will have to pay a lot for such work.
3. Low moisture resistance. Due to the porous structure of the blocks, moisture quickly penetrates into them, which does not allow their use in bathrooms.
4. Increased fragility of blocks. Air bubbles create a porous structure, and the material is easily subject to mechanical damage.

Mortar joints and armored belts reduce the thermal insulation of autoclaved aerated concrete blocks

Areas of use

The composition is environmentally friendly autoclave blocks publicly available both in mass and in individual construction. They are used in many areas, and due to their good thermal insulation properties, such blocks are used in the construction of schools, government agencies and hospitals. The large dimensions of the block allow the building to be quickly erected, which is very convenient in design multi-storey buildings. They are often used in the construction of room walls, as well as in the restoration of old buildings. Aerated concrete blocks are often used in the construction of summer houses, country houses, garages and extensions to the house.

Production

Non-autoclaved blocks require about a month of curing before use. Processing with an autoclave oven allows you to reduce the setting time of the material. The production of kiln blocks is often carried out by large manufacturers (autoclaved gas blocks are produced only in factories), since this requires expensive equipment and large premises. The production technology complies with GOST, therefore, when firing in autoclaves, specialists strictly observe certain temperatures and pressure in the furnace.

Preparing the Components

All Consumables are delivered to the plant by road and stored in special bunkers. Before use, quartz sand and other components undergo special treatment. Quartz sand is fed by belt conveyors into a ball mill, where it is finely ground into a powder-like mass. The mass is stored in large slurry basins equipped with a mixer, which brings the raw material to the desired consistency. The prepared material is fed into machines that form the required proportions of each component.

All work at factories for the production of autoclaved aerated concrete is automated

Dosing and mixing

The dosage of components is carried out according to a proven and proven recipe. Using automation, each component is accurately weighed and fed into the mixer. Before feeding aluminum powder, it also undergoes pre-treatment. This material is explosive, so all required fire safety standards are observed in the room.

Mixing of components occurs on special conveyors. The components are mixed with water until the consistency of sour cream is formed. Automated mixing is carried out at high speed for 4-5 minutes. After kneading, the mixer is cleaned with water and filled with the next portion.

Cutting into blocks

After mixing, the mass is poured into large steel molds to half its volume, since after swelling of the material it will fill the mold to the brim and become porous. Before cutting into blocks, the material is left for 2.5 hours to mature and gain the required strength. The maturation time of the mixture is determined by the recipe and external conditions created in the room. After this, the material is fed for cutting. Cutting of aerated concrete is carried out on automated lines using special strings. In a given sequence aerated concrete material Can be cut vertically or horizontally using a trimmer.

Cutting aerated concrete into blocks occurs on special lines using wire strings

Autoclave processing

Autoclave processing changes the molecular structure of the blocks, allowing them to finally ripen. Products are placed in an autoclave oven for an average of 12 hours. After closing the oven, the temperature automatically rises smoothly to 190 °C. When a vacuum is created inside the furnace, the pressure gradually increases to 12 bar. On modern factories Autoclaves are installed in which excess steam is automatically transferred from one oven to another.

Maintaining the created temperature is maintained in the oven for 6 hours

Sorting and packaging

After processing the blocks in ovens, they are unloaded using special equipment. The blocks move out on the grates one after another, and the crane removes them from the grates to load the next batch of blocks onto them.

The removed blocks are placed on wooden pallets and packed in film. Finished pallets are transported by forklift to the finished product warehouse. They are stored this way, protected from moisture. From the warehouse, goods are delivered to specialized stores.

Ready aerated concrete blocks stacked on pallets and packed with special film

To reinforce or not?

During the construction of residential and public buildings Reinforcement must be made from aerated blocks. This eliminates longitudinal deformation of the walls that occurs due to temperature changes and shrinkage of the material. The installed reinforcement will take on additional loads and increase the durability of the constructed building.

The need for reinforcement is foreseen by specialists during the design of the building. Most often, reinforcement is used:

• on structures with increased load;
• under window openings;
• after erecting the foundation while laying the first row of blocks;
• in every 3-4 rows of wall masonry.

Armature aerated concrete walls bears tensile loads

Many non-professional builders are concerned about the question:

1. "How ?" The rods are laid on both sides of the block in specially made grooves (grooves), they do not increase the thickness masonry joints and do not reduce the thermal insulation characteristics of aerated concrete blocks. Such grooves are cut with a hand wall chaser and, before laying the rods, they are cleaned of dust with a construction hairdryer. It is best to use periodic reinforcement with a diameter of 8 mm.
2. "?" There are many advantages and disadvantages when building a bathhouse from aerated concrete. Such blocks have high thermal insulation properties, economical, easy to work with, they do not rot and are completely environmentally friendly. Unlike wooden bath, such a bathhouse during the construction process requires additional costs for waterproofing and interior decoration, since this material has low moisture resistance. For reliable waterproofing In aerated concrete, fiberglass can be used, and the walls and floor can be insulated with mineral wool.
3. “What is the difference between aerated concrete and gas silicate?” Gas silicate is an autoclaved aerated concrete that contains lime and matures in autoclaves. The main material of conventional non-autoclaved aerated concrete is and it hardens naturally by curing for fresh air for a month. Production technology and different composition materials also affects the differences in color between these blocks (gas silicate has White color, aerated concrete – gray shade).

conclusions

Autoclaved aerated concrete has high quality indicators and is used for construction different types buildings. Like all materials, it has its advantages and disadvantages, which you need to familiarize yourself with before carrying out construction work. The advantage of autoclave units over non-autoclave units is that the former are produced in large automated factories and more often comply with GOSTs and quality standards.

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. Have different composition and various 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 usually takes place at 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 evenly distributed even after the cutting stage is completed finished material into building blocks, they are of ideal quality and homogeneous structure.

Fastenings

Since aerated concrete turns out to be very durable, it is possible to fix heavy materials and equipment. For example, ventilated facades made not only of lightweight materials, but also heavy ones of porcelain stoneware. In order for the fastening to be reliable, anchor bolts with polyamide expanding elements are used. 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 non-autoclave materials, they rely 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 result, 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 lower the thermal insulation performance of the building blocks. 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 advantage the price 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.

• Preparation of components. Some components come to production already in finished form, others are undergoing training. Quartz sand combined with water is ground to form sludge, and then constantly mixed in sludge basins and brought to the desired level. Aluminum powder also undergoes pre-production preparation.
• Dosage and mixing. Dosing and preparation of the mixture is performed automatically. All components, prepared in advance, are accurately weighed and filled into a large mixer. The prepared mixture is poured into metal molds- baths ½ of the volume. As a result, a chemical reaction of the components occurs with the formation of hydrogen and the block fills the entire mold and becomes porous. Hydrogen bubbles can be up to 3 mm. But the main thing is that they are almost uniform. This gives a homogeneous structure. Mixing time for all components is 5 minutes at high speed.

Aluminum powder is an explosive element, so strict adherence to fire safety measures is required in the room where AGB is produced.

Differences between autoclaved and non-autoclaved aerated concrete

The differences between the two building materials very large, from production to aging before delivery to the consumer. The composition of their recipes may be the same, but the technology in which autoclaved aerated concrete takes on the qualities artificial stone, differs significantly.

Specifications for comparison are presented below.

	Autoclaved	Non-autoclaved aerated concrete
Structure quality	Due to heating in an autoclave, it acquires the structure of artificial stone.	Hardens naturally in air or using steam at normal atmospheric pressure.
Life time	More than 100 years
Strength according to regulatory standards
Frost resistance
Thermal insulation and strength of the same parameters	Blocks 40 cm thick	Blocks 65 - 75 cm.
Block sizes	Cutting occurs automatically with minimal errors. Permissible deviations are on average 2.5 mm.	It is manufactured in collapsible formwork, which allows for significant deviations in the finished products. Deviations in sizes up to 5 mm.
	Precise dimensions require a minimum of connecting solution.	More mortar is required to level out uneven blocks.
Shrinkage of the finished product	Up to 0.4 mm/m
Structure of the finished block	Uniform throughout the entire depth.	They vary in the block and throughout the batch.
	Uniformly white. ATTENTION! The uneven color of autoclaved foam blocks indicates a violation of the recipe or manufacturing technology.	Heterogeneous gray.

An important factor is saving time on assembling building structures. Due to the precise cutting of the AGB already at the factory to known dimensions, it takes less time to adjust at the construction site and, accordingly, the process is less labor-intensive.

The automated process makes such aerated concrete expensive, but the benefits and advantages indicate the right investment. Autoclaved aerated concrete is of higher quality and has proven itself with the best side what is it in technical properties, and by appearance. Manufacturing technology makes aerated concrete an excellent material both for the construction of buildings and for creating a business.

There are quite a lot of debates about which aerated concrete is better - autoclaved or non-autoclaved. Manufacturers lead comparative characteristics, specialists conduct research and make calculations various designs from these materials. But one thing remains unchanged: it is quite possible to master the technology for making non-autoclaved foam concrete at home, and autoclave blocks can only be purchased.

What's happened non-autoclaved aerated concrete? This is the same foamed concrete, but hardened under normal conditions - without overpressure and with standard thermal and humidity treatment. It differs from “kiln” concrete in that its main component acts as a binder. For aerated concrete using a non-autoclave curing method, it is always cement; lime-containing gas silicate is obtained in autoclaves.

Sometimes blast furnace slag or gypsum is added to the composition, resulting in fundamentally new materials - gas-slag concrete and gas-gypsum, but in our country they are not in great demand.

Characteristics

Like all cellular concrete, non-autoclaved porous materials with high strength are characterized by low weight - 4-6 times less than that of a conventional monolith. Thanks to this, blocks from aerated concrete can be made very big size, which ensures faster work with less labor costs. This is what determined the popularity among developers that non-autoclaved and autoclaved aerated concrete has gained.

Another advantage of porous blocks is their good resistance to heat transfer - the numerous air capsules of which they are composed work as thermal insulators. Energy saving characteristics concrete is almost an order of magnitude higher than its dense “parent” and clinker bricks. This allows you to save on additional insulation, reducing construction costs to a minimum.

A pleasant bonus for everyone who is used to building on their own - aerated concrete can be processed well by any electric and even hand tools. This facilitates not only the construction of the box, but also the laying engineering systems, for which you need to cut grooves or drill holes in the walls.

Comparison with autoclaved aerated concrete

Still, it would be fairer to consider non-autoclaved concrete, comparing it with its autoclaved relative. In this section, normally hardening material has its advantages:

1. The ability to produce structures from aerated concrete of any size, up to continuous pouring into formwork for monolithic construction.

2. Simplified manufacturing scheme, which allows you to make non-autoclave products even at home.

3. Slightly higher resistance to moisture and frost, although they are far from optimal.

4. Relatively low production cost due to minimal energy consumption. The price for a cube of normal-hardening aerated concrete ranges from 2,800 to 3,200 rubles; for the same blocks from a kiln, the cost only starts at 3,200 rubles/m3.

At the same time, non-autoclaved foam concrete is inferior to gas silicate in terms of shrinkage by 7-10 times and almost twice as much in strength (class B 1.5 versus B 2.5). However, this is enough for the construction of private houses of 2-3 floors. Non-autoclaved aerated concrete has slightly higher thermal conductivity – about 0.17 W/m×°C. Because of this, the thickness of the walls has to be made 40% more.

Compound

In order to produce any amount of aerated concrete on your own, you will need to stock up on raw materials:

1. Portland cement - in solution it will take up about 50-60% of total mass. The most common brands of cement are suitable: M400 D0-D20 and M500 D0-D20.

2. Fillers – ash from thermal power plants, crushed limestone, blast furnace slag (40-50% of the total mass).

3. Blowing agent - this can be aluminum powder PAP (138-195 rubles/kg) or ready-made additives like POS-15 (150 rubles/kg). For 1 m3 of mixture you will need from 1,700 to 2,800 grams. The greater the porosity of aerated concrete is required, the higher the concentration of the blowing agent should be.

4. Modifiers - these additives are not mandatory, but they can be used to improve the characteristics of foamed concrete.

The modifiers are microsilica, calcium chloride, and semi-aqueous gypsum. Instructions for home production allow their replacement with table salt (0.2% of dry weight) or household washing powder (0.01%).

By the way, microsilica, like fly ash, introduced in a ratio of 1:10 or 1:20 to the mass of cement, slightly increases the strength class of foamed products. To zoom in specifications aerated concrete to the performance of more durable autoclaved blocks, reinforcing fibers are also introduced into the solution: basalt, polymer, asbestos.

Proportions for preparing formulations of different densities (in kg):

From the given number of components, 1 m3 of aerated concrete is obtained.

Production scheme

Foaming of a composition that has not yet hardened occurs due to the reaction of the alkaline components of the solution with the foaming agent. As a result, hydrogen is released, which forms numerous pores in the concrete body. This is the most critical stage in the production technology of a porous monolith, the flow of which will determine its final characteristics.

The manufacturing scheme itself is no different from conventional concrete work:

• preparing the solution;
• pouring into formwork;
• HME at the initial stage of hardening;
• final hardening.

In order to make aerated concrete with your own hands, you will need a regular concrete mixer, a shovel and buckets. All dry components can be weighed in a separate container before mixing in order to convert the mass proportions of the solution into volumetric ones. Only the blowing agent and modifiers (salt or washing powder) will need to be accurately weighed and divided into equal portions for each batch.

Is our quick guide will help you cook aerated concrete mixture and form it into blocks or a solid monolithic structure:

1. Mount removable formwork the right size, handle internal surfaces oil

2. In a separate container, add 50 parts water to 1 part aluminum powder, add washing powder.

3. Pour aluminum powder into the resulting composition and mix thoroughly so that no metal particles remain on the surface.

4. Pour the calculated volume of water into the mixer and start the unit.

5. Contribute required quantity filler, then add cement.

6. After 2-3 minutes of mixing, you can add lime, if it is present in the “recipe,” and aluminum suspension.

7. At the fourth minute, table salt is added, and already at the fifth minute the solution is quickly poured into the formwork.

In a month, when the concrete gains strength, it will be possible to cut off the top, dismantle the frame and make aerated concrete blocks with your own hands, cutting the monolith into pieces of the required size.

Take into account the peculiarities of the geometry of non-autoclaved concrete - during the process of foaming inside the cement paste, surfaces not limited by the formwork will heave. As a result, the so-called hump will grow at the top. Its size can reach 7% of the total volume of the structure, but this bubble will still have to be removed.

Sometimes it is necessary to speed up the hardening process of non-autoclaved pouring in order to quickly release the formwork and slightly mitigate the shortcomings of foam concrete. To do this, in the first 24 hours the structures provide a constant temperature in the range of +30-50 °C. But the level of humidity and pressure according to the instructions must correspond to normal environmental conditions. It is on these days that porous concrete gains about 50-60% of its strength.

With the increasing pace of construction activities, non-autoclaved aerated concrete has gained popularity among builders. The growing need for materials for construction requires an increase in production volumes and changes in technology.

In construction, professional terminology associated with types of raw materials is common. Autoclave and non-autoclave production methods are known. What are their features?

The tested technological process involved obtaining products using an autoclave method. This narrowed the scope of application of the resulting concrete mass and made it possible to produce only standard elements - lintels, blocks. Manufacturing methods have improved. The result is the production of raw materials made without autoclaving. This expanded the scope of use and allowed it to be used in the construction of monolithic structures.

A wide range of building materials sold allows you to choose the concrete most suitable for specific conditions

Distinctive features

Let's figure out what is the main difference between autoclaved aerated concrete and non-autoclaved aerated concrete? These are the conditions for the hardening of concrete mortar. They are divided into the following types:

• artificial, in which the course of hardening concrete mixture carried out under pressure exceeding atmospheric pressure, with an increased concentration of saturated vapors;
• natural, hardening naturally, using electrical heating or at atmospheric pressure, saturated with steam.

Non-autoclaved aerated concrete differs from autoclaved aerated concrete in the features of its manufacturing technology. It can be obtained quite simply without the use of autoclaves. This simple method carried out at a factory or test site. To do this, a mixture consisting of lime, cement, gypsum, and aluminum powder is poured into special molds. It hardens under normal conditions. This manufacturing method reduces electrical energy costs. The operation does not require special equipment. The resulting block is cut into finished fragments.

Autoclaved aerated concrete is produced by autoclaving. This is a complex operation that requires maintaining a steam pressure of 12 atmospheres and a temperature of up to 200⁰ C, at which the aerated concrete is “hardened” and acquires operational characteristics. Due to its high strength and durability, autoclaved aerated concrete is widely used in the construction of various objects: country houses, garages, cottages. Offices, high-rise buildings, and industrial facilities are no exception.

Aerated concrete is concrete with air or gas pores evenly distributed in it.

How are properties improved?

The characteristics of the composition produced without steaming in containers are increased as follows:

• Modifying components are added - microsilica, semi-aqueous gypsum.
• Hardening is accelerated by introducing calcium chloride.
• Bringing strength closer to parameters artificial material. For this purpose, dispersed reinforcing fibers of natural origin are introduced - basalt fiber, asbestos, as well as artificial ones - fiberglass or polymer components.
• They are strengthened by introducing acidic ash with a total volume of 10% of the cement mass.

The naturally hardened solution has high thermal insulation properties. The blocks obtained from it are quality characteristics are not inferior to traditionally produced ones, hardening in autoclaves.

Technological features, properties

As a result chemical reaction Using aluminum powder with alkali, which promotes gas formation, a synthetic gas-filled composite is obtained. A uniformly distributed porous structure is formed by hydrogen bubbles. Strength characteristics can be improved by adding modifiers. There are reagents that accelerate the hardening process. Experts believe that using composites reduces construction costs by 10 to 20%. This depends on the proportion of the mixture among the total range of items used. The energy-saving indicators achieved during use are also important.

Non-autoclaved aerated concrete matures in natural conditions or under certain exposure to temperature and moisture, but at normal atmospheric pressure

If we compare it with the widely used brick, then natural concrete reduces the need for energy resources. When operating objects built from it, energy costs are reduced by 20-25%.

Difficulty of choice

Which composition is better? There are three fundamental points related to the characteristics of concrete solutions. Let's take a closer look:

• The first is the amount of shrinkage of concrete compositions. The natural mixture, which hardens naturally, has an increased shrinkage of 2-3 millimeters per meter of pouring depth. Autoclaved aerated concrete shrinks significantly less. The layer reduction is 0.3 mm/m. This does not affect the quality of construction of monolithic objects. During hardening and shrinkage, the solution spreads under the influence of its weight, which compensates for the change linear dimensions. This disadvantage manifests itself in the production of prefabricated structures.
• The next factor is the time required for curing. Conventional material takes longer to acquire the required strength properties.
• Strength factors are important. Autoclaving technology promotes the formation of a special mineral - tobermorite, which increases strength. This substance is not formed during traditional way. This limits the scope of use of naturally curing composites. Scope of application: structures operating under light loads.

You can determine the difference between each type of concrete by considering autoclaving.

Non-autoclaved aerated concrete has a large number of pores with a diameter of up to 3 mm, evenly distributed throughout its volume

Production Features

Autoclaving is the operation of steaming a concrete composition in special metal containers called autoclaves. Concrete mortar at given parameters (temperature, pressure) it acquires high strength properties that cannot be achieved in the usual way. This treatment not only reduces the hardening time of the mixture. The main feature is changes at the molecular level. The result is that the composition acquires unique strength characteristics. Aerated concrete produced in an autoclave is synthesized. This is an artificially obtained stone. It differs from cement-sand concrete, which hardens porous.

Products obtained in different ways have their own performance characteristics, composition, physical and technical parameters. The main indicators of the concrete produced are quite high. Manufacturing features and parameters are regulated by various regulatory documents. Innovative technological methods used by Europeans are gradually replacing ineffective, outdated production methods.

Important Details

Let's look at how each material differs. The scope of application is determined by:

• Quality. The synthesized product is produced at large enterprises. It is transported to construction site ready-made blocks. It is impossible to make this gas concrete by hand. Many parameters are controlled during its manufacture. Enterprises equipped with autoclaves have a high automation rate of 95%. The human factor has virtually no effect on production. Quality is confirmed by certificates of conformity. Natural compositions do not require major capital investments and are inexpensive.

• Strength factors. Cellular composites differ in density and strength class. At equal density ordinary products inferior in physical characteristics and strength.
• Fastening properties. The synthesized composite allows for fixing heavy equipment: ventilation systems, air conditioners, heaters. For this purpose they use anchorage spacer type.
• Stable density. Gas formation using the autoclave method occurs throughout the entire environment. At the same time, the mixture hardens, the pores are uniformly distributed throughout the volume. The formation of blocks from the resulting mixtures is carried out by cutting the hardened mass. This is a guarantee of the quality of the blocks. When producing naturally hardening concrete, foam with gas-forming agents is introduced into the solution. During mixing, light components float and heavy fillers settle. Uneven distribution of cavities occurs. The density of different blocks is different. Stability of indicators is associated with homogeneity, which affects strength.
• Environmental friendliness. Synthetic is completely safe for others gas composition. This affects the microclimate of the building, which is favorable for living. The mineral components used do not rot. This ensures that mold and fungi cannot form. The decrease in the environmental friendliness of foam concrete is due to the use of waste from the production of crushed stone, local sand, and chemical fillers. This negatively affects the microclimate of the room.
• Compliance with dimensions. Standards regulate deviations in the length, width, and thickness of blocks obtained in autoclaves. The tolerance value does not exceed 3 millimeters. Naturally hardening concrete products are characterized by large dimensional deviations - up to 5 mm. Tolerances in the geometry of the blocks worsen the masonry: more mortar is required, labor intensity increases, and costs increase.