The gas block is 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?

Autoclave treatment - 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 aerated concrete hardening;
increased strength;
reduction of shrinkage;
improving the uniformity of the structure;
improved block geometry.

The autoclave also 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.

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

Now let's take a closer look at the differences in aerated concrete, and we'll start with strength.

Comparison of autoclaved and non-autoclaved aerated concrete

It is important to note that in the video non-autoclaved aerated concrete is tested, to which fiber has been added, it significantly increases the strength of the blocks. But note that in reality, fiber in the production of non-autoclaved aerated concrete is not used by everyone, since it is quite expensive.

Strength

Aerated concrete without an autoclave is less durable, especially when fresh. After all, it, like ordinary concrete, needs more time to gain strength, while autoclave hardening accelerated hundreds of times due to high-temperature steam treatment. But even with the 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 B2.5 - B3.5, while a non-autoclave analogue of the same brand gains B2 class at best.

Shrinkage

Large shrinkage of blocks can create multiple cracks in the masonry; moreover, cracks can appear within 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 laying.

Block geometry

The geometry of the blocks is also very important, and the smoother the blocks are, the better. Indeed, if the blocks differ from each other by 5 mm, then the difference in level must be leveled with glue, and these are cold bridges, which greatly worsen the thermal insulation characteristics of the masonry.

Moreover, thick seams tend to shrink heavily, which again can cause cracks. Experienced builders will say that the difference in levels can be leveled with a trowel on aerated concrete, but imagine how long it will take.

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

Most builders believe that the best, smoothest blocks come from AEROC. The average price per cube of their aerated concrete is 4000r.

Uniform structure

Uniformity means the number of voids (bubbles) that are distributed in a certain way in aerated concrete, and the more uniform they are, the better. The autoclaved aerated concrete technology guarantees an ideal 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 made in a completely different way. Foam and blowing agents are added to the concrete mixture. As a result, bubbles can rise closer to the surface, and 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 indicators of non-autoclaved aerated concrete are very unstable.

Thermal conductivity

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

Output

Autoclave and non-autoclave aerated concrete are very different from each other in a number of parameters, and it is safe to say that autoclave material surpasses its counterpart in all respects, except for one - price. Yes, non-autoclaved gas blocks are cheaper, but if you count 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 competently once, from quality material, and be sure that it will stand for many years without problems.

The sphere of construction has been developing since the appearance of man. In the modern world, the development of this industry plays a crucial 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 allowed the above material to take its rightful place in construction. One of the types of concrete is the so-called aerated concrete.

Concrete types

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

aerated concrete;
foam concrete.

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

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

Aerated concrete

The main difference from the material to which everyone is accustomed is that it is aerated 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.

The advantages of aerated concrete

The 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 quality level 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 number 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 what production technology was used during the manufacture of blocks, aerated concrete is divided into two types. Such as the:

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 take a closer look at each of these types.

Which is better autoclaved or non-autoclaved concrete

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

At firstone of the most significant differences is quality stability.
A block of autoclaved aerated concrete can only be produced in large production. Since for its production it is necessary to control several dozen of the most diverse processes, as well as parameters. Plants that produce 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 confident in its reliability.
But many will think that the manufacture of non-autoclave gas blocks does not require a huge enterprise and this factor will affect the cost of this building material. However, can this be considered an advantage? Since, in essence, it can be called “handicraft” production, which has rather unstable quality indicators.

Secondly, strength is also an important characteristic for absolutely any building material.
The characteristics that affect the strength of the material are density and compressive strength. The most common are D500 and D600, in which case aerated concrete made by autoclaving 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, in the best case, reach B2.

Thirdly, possibility of fastening. Carrying out the autoclaving process allows achieving impressive strength characteristics of the material. Thanks to this, one anchor at the base of autoclaved aerated concrete can withstand an impressive load of up to 700 kilograms.

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

Fifth, material homogeneity.
The aerated concrete block during its production is filled with gas evenly throughout the entire 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 quality and reliability.

A non-autoclave block, on the other hand, is obtained by introducing foam and a blowing agent into the solution, and then stirring them. In the end, it turns out that the 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 influenced, first of all, by the density of the material. That is, the higher the density of the material, the lower the level of thermal insulation. This proves that aerated 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 - an autoclaved aerated concrete block.

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 widespread. Known autoclave and non-autoclave production method. What are their features?

Proven technological process provided for obtaining products by autoclaving. This narrowed the scope of application of the resulting concrete mass, making it possible to manufacture only standard elements - lintels, blocks. Manufacturing methods have improved. The result is the receipt of raw materials made without autoclaving. This expanded the area of \u200b\u200buse, made it possible to use it in the construction of monolithic structures.

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

Distinctive features

Let's figure out what is the main difference between autoclaved aerated concrete and non-autoclaved? 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, with an increased concentration of saturated vapors;
natural, hardening naturally, with the use of electric heating or at atmospheric pressure, saturated with steam.

Non-autoclaved aerated concrete differs from autoclave in the peculiarities of the manufacturing technology. It can be obtained quite simply without the use of autoclaves. This is an uncomplicated method carried out in a factory or landfill. For this, a mixture of lime, cement, gypsum, aluminum powder is poured into special molds. 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 ready-made 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 200⁰C, at which aerated concrete "hardens" and acquires operational characteristics. Due to its high strength, durability, autoclaved aerated concrete is widespread in the construction of various objects: country houses, garages, cottages. Offices, high-rise buildings, industrial facilities are no exception.

Aerated concrete is a concrete with evenly distributed air or gas pores 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.
Strength is brought closer to the parameters of artificial material. For this, dispersion-reinforcing fibers of natural origin are introduced - basalt fiber, asbestos, as well as artificial fibers - fiberglass or polymer components.
Strengthened by introducing acidic ash with a total volume of 10% of the cement mass.

Naturally hardened mortar has high thermal insulation properties. The blocks obtained from it are not inferior in quality characteristics to those traditionally produced, hardened 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. The uniformly distributed porous structure is formed by hydrogen bubbles. Improving the strength characteristics can be achieved by adding modifiers. There are reagents that accelerate the curing process. 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 nomenclature of used items. The energy-saving indicators achieved during use are also important.

Non-autoclaved aerated concrete matures under natural conditions or under a certain influence of temperature and moisture, but under normal atmospheric pressure

If we compare it with the widely used brick, then natural concrete reduces the need for energy resources. During the operation of facilities built from it, energy consumption is reduced by 20-25%.

Difficulties of choice

Which composition is better? There are three fundamental points associated with the features of concrete solutions. Let's take a closer look:

The first is the amount of shrinkage of concrete compounds. A natural mixture that 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 the construction 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 manifests itself in the production of prefabricated structures.
The next factor is the time it takes to cure. For a conventional material, it takes more time to acquire the required strength properties.
Strength factors are also important. Autoclaving technology promotes the formation of a special mineral - tobermorite, which increases strength. This substance is not formed in the course of the traditional method. This limits the area of \u200b\u200buse of the naturally hardened composite. Scope of application - structures that function 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 with a diameter of up to 3 mm, evenly distributed over its volume

Features of production

Autoclaving is the operation of steaming concrete composition in special metal containers called autoclaves. Concrete mortar at the given parameters (temperature, pressure) it acquires high strength properties that cannot be achieved in the usual way. This treatment not only shortens 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.

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

Important details

Let's consider how each of the materials differs. The scope of application is determined by:

Quality. The synthesized product is produced at large enterprises. It is transported to the construction site in finished 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 rate of 95%. The human factor practically does not affect production. The quality is confirmed by certificates of conformity. Natural formulations do not require serious capital investments, they are distinguished by a low price.

Strength factors. Cellular composites differ in density, strength class. With an equal density, conventional products are inferior in terms of physical characteristics and strength.
Fastening properties. The synthesized composite allows fixing heavy equipment: ventilation systems, air conditioners, heaters. For this, a spacer type anchor is used.
Stable density. Autoclave gassing occurs throughout the 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 solidified mass. This is a guarantee of the quality of the blocks. In the production of naturally hardening concrete, foam with blowing agents is introduced into the solution. During mixing, light components float up, heavy fillers settle. There is an uneven distribution of cavities. The density of different blocks is different. Performance stability is related to uniformity, which affects strength.
Environmental friendliness. Synthetic gas composition is completely safe for others. This affects the building's microclimate, favorable for living. The mineral components used do not rot. This ensures that mold and mildew cannot form. A decrease in the environmental friendliness of foam concrete is due to the use of crushed stone production waste, local sand, chemical fillers. This negatively affects the indoor climate.
Compliance with dimensions. The standards regulate the deviations of the length, width, and thickness of blocks obtained in autoclaves. The tolerances do not exceed 3 millimeters. Naturally hardening concrete products are characterized by large dimensional deviations - up to 5 mm. The geometry tolerances 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 field of application of which is the construction of buildings with a height of 1-3 floors. Low density and high thermal 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 minimum thickness.

This article discusses two types of aerated concrete - materials of natural and autoclave 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 surpasses natural hardening material in all performance characteristics. Let's consider its main advantages:

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

As a comparison, here are the characteristics of both materials:

In terms of 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, animal sheds, gazebos. The difference in the price of materials is about 15-20%.

About 90 large factories and an uncountable number of small enterprises are engaged in the production of aerated concrete in Russia. Among the trusted suppliers, we note the following companies:

Aerok;
Bonolit;
AeroStone.

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

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

thermal insulation: EcoTerm (D400) and EcoTerm + (D300);
structural: Classic (D500) and Hard (D600);
jumpers 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.

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

Preparation of components. Some components come to production ready-made, others are being trained. Quartz sand, combined with water, is ground to form sludge, and then it is constantly mixed in the slurry tanks and brought to the required value. Aluminum powder also undergoes pre-production preparation.
Dosage 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 - baths by 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 acquires porosity. Hydrogen bubbles can be up to 3 mm. But the main thing is that they are practically uniform. This gives a uniform structure. The mixing time for all components is 5 minutes at high speed.

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

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 formulations may be the same, but the technology, in which autoclaved aerated concrete takes on the qualities artificial stone, differs significantly.

The characteristics for comparison are presented below.

	Autoclave	Non-autoclaved aerated concrete
Structure quality	Due to heating in an autoclave, it acquires the structure of an artificial stone.	It hardens naturally in air or using steam at normal atmospheric pressure.
Life time	Over 100 years
Strength by regulation standards
Frost resistance
Thermal insulation and strength of some parameters	Blocks 40 cm thick	Blocks 65 - 75 cm.
Block sizes	Slicing takes place automatically with minimal errors. Permissible deviations average 2.5 mm.	It is manufactured in a collapsible formwork, which allows significant deviations in the finished products. Deviations in dimensions up to 5 mm.
	The exact dimensions require a minimum of joint mortar.	More mortar is required to level out uneven blocks.
Shrinkage of the finished product	Up to 0.4 mm / m
Finished block structure	It is 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 recipe or manufacturing technology.	Dissimilar gray.

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

An automated process makes such aerated concrete expensive, but the benefits and advantages speak for the correct investment. Autoclaved aerated concrete is of higher quality, and has proven itself from the best side both in terms of technical properties and appearance... Manufacturing technology makes aerated concrete an excellent material for both building construction and business creation.