Gas block autoclave and non-autoclave difference. What is non-autoclaved aerated concrete, its properties and production. Many non-professional builders are concerned about the issue

Aerated concrete happens autoclave and non-autoclave, and many builders are wondering what are the differences between them.

Let's figure it out together, but looking ahead, let's say that autoclaved aerated concrete is a much better material, and then we'll tell you why.

What is Autoclaved Aerated Concrete?

Autoclaving – the stage of processing aerated concrete with high temperature (190°C) under high pressure during 12 hours. Autoclaves are metal containers in which cut gas blocks are placed.

Autoclaving is done for the following purposes:

acceleration of hardening of aerated concrete;
increase in strength;
shrinkage reduction;
improving the uniformity of the structure;
block geometry improvement.

Also, the autoclave changes the structure of aerated concrete at the molecular level, forming new material – tobermorite. This synthesized stone has properties that cannot be obtained in normal conditions at standard pressure and temperature.

We repeat that non-autoclaved aerated concrete hardens in natural conditions, and for its production is expensive and modern equipment not required. In other words, many manufacturers stamp gas blocks in their garages, which does not inspire much confidence.

And now we will understand in more detail the differences in aerated concrete, and we will start with strength.

Comparison of autoclaved and non-autoclaved aerated concrete

It is important to note that non-autoclaved aerated concrete is tested in the video, to which fiber was added, it significantly increases the strength of the blocks. But we note that in reality, far from everyone uses fiber in the production of non-autoclaved aerated concrete, since it is quite expensive.

Strength

Aerated concrete without an autoclave is less durable, especially when fresh. After all, like ordinary concrete, it still needs time to gain strength, while autoclaved hardening accelerated hundreds of times due to high-temperature steam treatment. But even with complete hardening of both materials, the strength of the autoclave is higher by half or more.

For example, autoclaved aerated concrete grades D500 and D600 have a strength class of B2.5 - B3.5, while a non-autoclaved analogue of the same brand is gaining class B2 at best.

Shrinkage

Large shrinkage of blocks can create multiple cracks in the masonry, moreover, cracks can appear for a year or more. To minimize such processes, block shrinkage should be minimal.

Shrinkage of non-autoclaved aerated concrete is from 3 to 5 mm per meter, autoclaved - ten times less. That is, autoclaved aerated concrete practically does not give shrinkage cracks, with proper masonry.

Block geometry

The geometry of the blocks is also very important, and the more even the blocks are, the better. After all, if the blocks differ by 5 mm, then the difference in level must be leveled with glue, and these are cold bridges that greatly worsen the thermal insulation characteristics of the masonry.

Moreover, thick seams give a lot of shrinkage, which again can cause cracks. Experienced builders will say that the difference in levels can be leveled with a grater on aerated concrete, but imagine how long it will take.

And now let's think about where the geometry of the blocks will be better, on high-tech factory equipment with autoclaves, or in garage conditions? The answer is obvious!

Most builders believe that the best and most even blocks come from AEROC. The average price per cube of their aerated concrete is 4000 rubles.

Structure homogeneity

Uniformity refers to the number of voids (bubbles) that are distributed in a certain way in aerated concrete, and the more uniform they are, the better. Autoclaved aerated concrete technology guarantees a perfect distribution of voids, due to the fact that bubbles form and immediately harden, and individual blocks are obtained after cutting one large block.

Non-autoclaved aerated concrete is done quite differently. Foam and blowing agents are added to the concrete mix. As a result, bubbles can rise closer to the surface, while heavier elements fall down. As a result, the distribution of bubbles will be uneven.

Now let's think about what it threatens. Firstly, where there are fewer bubbles, there is less strength, and where there are few bubbles, there is a cold bridge through which heat will escape faster. That is, the strength and thermal conductivity of non-autoclaved aerated concrete is very unstable.

Thermal conductivity

Smoothly moving from the topic of structural uniformity to thermal conductivity, let's say that the uneven structure of the bubbles worsens the average thermal conductivity of the block, and it is natural that in autoclaved aerated concrete the uniformity of the bubbles is better and, therefore, the thermal insulation is also better.

Conclusion

Autoclaved and non-autoclaved aerated concrete are very different from each other in a number of parameters, and it can be said with confidence that the autoclaved material is superior to its counterpart in all respects, except for one thing - the price. Yes, non-autoclaved gas blocks are cheaper, but if you consider how many problems arise when laying it, how many additional materials, work and time you have to do, then we advise you to think carefully when making your choice.

It is better to build a house correctly once, from quality material, and be sure that it will stand without problems for many years.

The construction industry has been developing since the appearance of man. IN modern world The development of this industry plays an important role in the life of today's society.
Concrete- the material that has proven its reliability and durability over its hundred-year history. It is these characteristics that have allowed the above material to take its rightful place in construction. One of the varieties of concrete is the so-called aerated concrete.

Types of concrete

According to the method of pore formation, cellular concrete is divided into the following types:

aerated concrete;
foam concrete.

As for the conditions of hardening, there is also a classification here. Subdivisions of concrete according to hardening conditions:

Autoclave. Curing takes place in an environment of saturated steam and under the action of pressure, which is much higher than atmospheric pressure.
Non-autoclave. The hardening process occurs under natural conditions, with electrical heating or with atmospheric pressure in a saturated steam environment.

aerated concrete

The main difference from the material to which everyone is accustomed is that it is cellular concrete. This material has found its application in the construction of walls of any type (bearing or non-bearing), reinforced slabs, and it is also used to provide thermal insulation.

Advantages of aerated concrete

Distinctive characteristics of this building material are:

high level of thermal insulation;
Fire safety;
long service life;
relatively low cost.

It should be noted that the level of quality of aerated concrete blocks, as well as buildings made from it, depends on the raw materials used, production technology and equipment of the enterprise.

Characteristics of aerated concrete

aerated concrete- cellular material (concrete), in which there is a huge amount of air-filled pores, which significantly reduce the density of the material. In most cases, the percentage of air in aerated concrete can reach 90% of the total volume.

What are the types of aerated concrete

Depending on which production technology was used during the manufacture of blocks, aerated concrete is divided into two types. Such as:

autoclave;
non-autoclave.

At the present time, quite often the question arises related to which of the above types is better. In order to understand this, it is necessary to consider each of these types in more detail.

What is better autoclaved or non-autoclaved concrete

The steaming process in metal capsules, so-called autoclaves, during the action high pressure and temperature is called autoclaving.
It should be noted that pressure, sometimes reaching 12 atmospheres, and a temperature of 190 degrees Celsius make it possible to create a unique material that cannot be obtained under normal conditions.
The main task of autoclaving is not only to accelerate the process of hardening of the solution, but also under the influence of extreme conditions, changes occur at the molecular level, which leads to the formation of such a mineral as tobermorite. That is why autoclaved aerated concrete is an artificially obtained stone, and non-autoclaved concrete, in turn, is a solution of cement and sand that has hardened in a porous state.
Do not forget that aerated concrete of the above types (autoclaved and non-autoclaved) have a number of differences. Starting from the composition and ending with the performance characteristics, autoclaved aerated concrete surpasses its rival in all respects. Let's look at this issue in more detail.

Firstly, one of the most significant differences is the quality stability.
A block of autoclaved aerated concrete can only be produced in large-scale production. Since for its production it is necessary to control several dozens of the most diverse processes, as well as parameters. Plants engaged in the production of gas blocks have a fairly high degree of automation (about 95%) and practically do not allow a person to influence the manufacturing process.
If we take into account GOST, then each batch of autoclaved aerated concrete has its own quality certificate. So the client can be completely sure of its reliability.
But many will think that the manufacture of non-autoclaved gas blocks does not require a huge enterprise, and this factor will affect the cost of this building material. However, can this be considered a virtue? Since, in essence, this can be called "handicraft" production, which has rather unstable quality indicators.

Secondly, strength is also an important characteristic for absolutely any building material.
Characteristics that affect the strength of the material are density and compressive strength. The most common are D500 and D600, in which case the autoclaved aerated concrete has a compressive strength of about B2.5 and B3.5, respectively. In this variant, non-autoclaved concrete also loses significantly, since at a density of D600 its compressive strength will reach B2 in the best case.

Third, the possibility of fastening. The autoclaving process allows to achieve impressive strength characteristics of the material. Thanks to this, one anchor in the base of autoclaved aerated concrete can withstand an impressive load of up to 700 kilograms.

Fourth, environmental friendliness also plays an important role during the choice of material. Immediately it should be said that autoclaved aerated concrete is a completely environmentally friendly material. This characteristic allows you to create a cozy climate for living in the house, which is quite similar to the microclimate of a house built of wood.

Fifth, homogeneity of the material.
A block of aerated concrete during its production is filled with gas evenly throughout the volume. Also, in parallel with this process, the material hardens. Thanks to this production strategy, the pores are most evenly distributed over aerated concrete block, which guarantees the buyer the maximum indicator of quality and reliability.

A non-autoclave block, on the contrary, is obtained by introducing foam and a blowing agent into the solution, after which they are mixed. In the end, it turns out that air bubbles "float" to the surface, and all the remaining components settle to the bottom. This leads to the fact that the pores are randomly distributed over the volume of the material, which does not allow achieving the required quality on all blocks.

At sixth, thermal insulation properties. Each person will say that the thermal insulation characteristics are affected, first of all, by the density of the material. That is, the greater the density of the material, the lower the level of thermal insulation. This proves that foam concrete, non-autoclaved and autoclaved aerated concrete have the best thermal insulation performance due to their low density.

Conclusion. Based on the foregoing, it can be noted that the construction of non-autoclaved aerated concrete is much cheaper. But this should not be considered a virtue. Since the characteristics of this material are quite inferior to its competitor - autoclave block from aerated concrete.

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

In construction, professional terminology related to the types of raw materials is common. Known autoclave and non-autoclave method of production. What are their features?

Proven technological process provided for the production of products by autoclave. This narrowed the scope of the resulting concrete mass, made it possible to produce only standard elements - lintels, blocks. Manufacturing methods have improved. The result is a raw material made without autoclaving. This expanded the scope of use, allowed it to be used in the construction of monolithic structures.

A wide range of sold building materials allows you to choose the most suitable concrete 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 the concrete solution. They are divided into the following types:

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

Non-autoclaved aerated concrete differs from autoclaved in the features of manufacturing technology. It can be easily obtained without the use of autoclaves. This is a simple method carried out at a factory or landfill. To do this, a mixture consisting of lime, cement, gypsum, aluminum powder is poured into special forms. It hardens under normal conditions. This manufacturing method reduces the cost of electrical energy. 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 "hardens" and acquires operational characteristics. Due to its high strength, durability, autoclaved aerated concrete is widely used in the construction of various objects: country houses, garages, cottages. Offices, high-rise buildings, 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 the introduction of calcium chloride.
Approximate strength to the parameters of artificial material. For this, dispersed-reinforcing fibers of natural origin are introduced - basalt fiber, asbestos, as well as of an artificial nature - fiberglass or polymer components.
Strengthen by introducing acid ash with a total volume of 10% of the mass of cement.

Naturally hardened mortar has high thermal insulation properties. The blocks obtained from it in terms of quality characteristics are not inferior to those traditionally produced, hardening in autoclaves.

Technological features, properties

As a result of the chemical reaction of 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. Improvement in strength characteristics can be achieved by adding modifiers. There are reagents that accelerate the course of hardening. Experts believe that with the use of a composite, construction costs are reduced by 10 to 20%. It depends on the proportion of the mixture among the general range of applied items. Energy-saving indicators achieved during use are also important.

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

When compared with widely used bricks, natural concrete reduces the need for energy resources. During the operation of objects built from it, energy costs are reduced by 20-25%.

Difficulties of choice

What composition is better? There are three fundamental points associated with 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 much less. The layer reduction is 0.3 mm/m. This does not affect the quality of erection of monolithic objects. During hardening and shrinkage, under the influence of its weight, the solution spreads, which compensates for the change linear dimensions. This disadvantage is manifested in the production of prefabricated structures.
The next factor is the time required for curing. For a conventional material, it takes more time to acquire the necessary strength properties.
Strength factors are important. Autoclaving technology contributes to the formation of a special mineral - tobermorite, which increases strength. This substance not formed during the traditional method. This limits the scope of use of the naturally hardening composite. Scope of application - structures operating at low loads.

You can determine how each type of concrete differs by considering autoclaving.

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

Production features

Autoclaving is the operation of steaming the 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. Such processing not only reduces the hardening time of the mixture. The main feature is changes at the molecular level. The result - the composition acquires unique strength characteristics. Aerated concrete produced in an autoclave is synthesized. This is a man-made stone. It differs from cement-sand concrete, which hardens porous.

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

Important Details

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

Quality. The synthesized product is produced at large enterprises. It is transported to the construction site in ready-made blocks. It is impossible to make this gas concrete by handicraft. Many parameters are controlled during its manufacture. Enterprises equipped with autoclaves have a high automation ratio of 95%. The human factor practically does not affect production. The quality is confirmed by certificates of conformity. Natural formulations do not require serious investment, they are distinguished by a small price.

strength factors. Cellular composites differ in density, strength class. With equal density, conventional products lose in terms of physical characteristics and strength.
fastening properties. The synthesized composite allows you to fix heavy equipment: ventilation systems, air conditioners, heaters. For this, a spacer-type anchor is used.
stable density. Gas formation according to the autoclave technique occurs in the entire environment. At the same time, the mixture hardens, the pores are uniformly distributed over the volume. The formation of blocks from the resulting mixtures is carried out by cutting the hardened array. This is a guarantee of the quality of the blocks. In the production of naturally hardening concrete, foam with gas generators is introduced into the solution. During mixing, light components float and heavy fillers settle. There is an uneven distribution of cavities. The density of different blocks is different. The stability of indicators is associated with uniformity, which affects strength.
Environmental friendliness. Synthetic gas composition is completely safe for others. This affects the microclimate of the building, favorable for living. The applied mineral components do not rot. This ensures the impossibility of the formation of mold, fungi. The decrease in the environmental friendliness of foam concrete is due to the use of waste products from the production of crushed stone, local sand, and chemical fillers. This negatively affects the microclimate of the room.
Size compliance. The standards regulate deviations in the length, width, thickness of blocks obtained in autoclaves. The value of tolerances does not exceed 3 millimeters. Naturally hardening concrete products are distinguished by a large dimensional deviation - up to 5 mm. Tolerances in the geometry of the blocks worsen the masonry: more mortar is required, labor intensity increases, and costs increase.

Aerated concrete is a popular building material, the main scope of which is the construction of buildings with a height of 1-3 floors. Low density and high heat resistance make it possible to build walls from gas blocks, the mass of which is 3-4 times lower than the weight of similar brick walls. Today, it is the only building material suitable for the construction of strong and warm walls of minimal thickness.

This article discusses two types of aerated concrete - materials of natural and autoclaved hardening. We will study their raw material composition and production technology, get acquainted with the differences, advantages and disadvantages, and also determine which cellular concrete is better.

Autoclaved aerated concrete is superior to natural hardening material in all performance characteristics. Consider its main advantages:

Stable quality. The production of autoclaved aerated concrete is possible only in large-scale production, while a non-autoclaved analogue can be made even at home, which is why blocks of dubious quality often enter the market.
Strength. Autoclaved aerated concrete is produced in D400-800 density, its compressive strength varies between B1.5-B5, while the maximum strength of non-autoclaved material does not exceed B3. On the wall of thermally hardened blocks, you can mount not only cabinets and shelves, but also heavier objects - speakers, air conditioners, the weight of which cannot be supported by non-autoclaved cellular concrete.
No shrinkage during operation. Shrinkage associated with the evaporation of the moisture contained in the material is the main reason for the appearance of cracks on the walls of gas blocks. The lower the density of the material, the more it shrinks in the process of residual curing, which continues for 5-10 years after the production of blocks. Autoclaved aerated concrete shrinks by an average of 0.5 m/mm, while non-autoclaved aerated concrete shrinks by 2-3 mm/m.
Geometry. Blocks cut from the array always have smaller deviations from the design dimensions than products formed by injection molding in separate forms. The discrepancy between the dimensions of cellular concrete of natural hardening leads to an increase in the thickness of the masonry joints (cold bridges are formed) and problems in finishing the facade of the building.

As a comparison, we present the characteristics of both materials:

According to the totality of operational characteristics for the construction of residential buildings, it is much better to use autoclaved aerated concrete, while its analogue can be used for the construction of technical buildings - garages, sheds for animals, gazebos. The difference in the price of materials is about 15-20%.

About 90 large factories and countless small enterprises are engaged in the production of cellular concrete in Russia. Among the verified suppliers, we note the following companies:

Aerok;
Bonolite;
AeroStone.

The largest manufacturer in Russia is Aerok, whose volume of deliveries exceeds 400 thousand m 3 of aerated concrete during the year. It was Aerok who in 2005 introduced blocks with a strength of B2.5 and a density of D400, which later became the standard in the field of low-rise construction.

The range of the company includes the following types of blocks:

heat-insulating: EcoTerm (D400) and EcoTerm + (D300);
structural: Classic (D500) and Hard (D600);
lintels and U-shaped blocks.

The company supplies all common block sizes. The quality of its products is confirmed by full compliance production process requirements of GOST No. 31360.

As an analogue of Aerok aerated concrete, it makes sense to consider the products of Bonolit, the second most popular manufacturer in Russia. First of all, the company is known for its line of autoclaved aerated concrete Bonolit40, which is designed specifically for the Russian climate and ideally manifests itself at temperatures from -40 to +40. In addition to the supply of products, the company offers services for the construction of turnkey houses from cellular concrete.

Preparation of components. Some components come to production ready-made, others are being prepared. Quartz sand, combined with water, is ground to form sludge, and then in sludge pools it is constantly mixed and brought to the desired level. Aluminum powder also undergoes pre-production preparation.
Dosing and mixing. Dosing and preparation of the mixture is carried out automatically. All components prepared in advance are accurately weighed and filled into a large mixer. The prepared mixture is poured into metal molds - bathtubs 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 form and acquires porosity. Hydrogen bubbles can be up to 3 mm. But the main thing is that they are almost uniform. This gives a uniform structure. Mixing time of all components is 5 minutes at high speed.

Aluminum powder is an explosive element, therefore, strict compliance with fire prevention measures is required in the room where AGB is produced.

Differences between autoclaved and non-autoclaved aerated concrete

The differences between these 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 shown below.

	autoclaved	Non autoclaved aerated concrete
Structure quality	By heating in an autoclave, it acquires the structure of an artificial stone.	Cures naturally in air or using steam at normal atmospheric pressure.
Life time	Over 100 years
Strength of Regulatory Standards
Frost resistance
Thermal insulation and strength of one 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 made in a collapsible formwork, which allows significant deviations in finished products. Deviations in sizes up to 5 mm.
	Accurate dimensions require a minimum of joint mortar.	More mortar is needed to level uneven blocks.
Shrinkage of the finished product	Up to 0.4 mm/m
The structure of the finished block	Uniform throughout the depth.	They differ in the block and throughout the party.
	Uniformly white. ATTENTION! The uneven color of autoclaved foam blocks indicates a violation of the formulation or manufacturing technology.	Miscellaneous grey.

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

The automated process makes such aerated concrete expensive, but the benefits and benefits speak to the right investment. Autoclaved aerated concrete is of higher quality, and has proven itself from the best side both in terms of technical properties and appearance. The manufacturing technology makes aerated concrete an excellent material both for building buildings and for creating a business.