The sphere of modern construction invariably pleases us with novelties, thanks to which the process of erecting buildings becomes less lengthy, and its result is as close as possible to expectations. As soon as foam blocks and gas blocks appeared on the building materials market, they made a real splash. However, this was quite expected, because their advantages are obvious, and the range of application is quite wide. Nevertheless, if you decide to buy one of these building materials, first you need to properly understand not only their differences, but also individual advantages and disadvantages.

The main thing is not to rely on the subjective opinion and experience of pseudo-specialists, but to trust the recommendations and reviews of professionals. They, in turn, divided into several camps, two of which consist of adherents of one or another category of goods. others are from those who are convinced that all the controversy about their differences is far-fetched and is nothing more than a marketing ploy, and therefore there is no need to argue which foam block or gas block is better for construction.

Naturally, the main differences between the building materials mentioned above arise even at the stage of their direct production. Both products belong to the category of lightweight concretes, which are traditionally made exclusively from highly environmentally friendly raw materials. At first glance, they may seem similar, meanwhile, the procedure for their manufacture is significantly different. Even the pores that define these building materials appear in the blocks as a result of completely different technological manipulations.

Features of the manufacture of foam concrete

The entire production process can be divided into a number of operations:

• the ingredients of the substance are combined, the foaming element is added last;
• using a mechanized method, concrete and foam are mixed;
• under natural conditions, the finished solution hardens.

All the necessary equipment required for the implementation of such technology is very democratic in its price category, and therefore quite affordable even for novice entrepreneurs. Because of this, manufacturers of foam blocks, as a rule, are small, almost home-based enterprises.

The products of such organizations, as a rule, are not ideal at all. The final products do not have a smooth surface or proportionality of parameters, which greatly complicates their use.

Production of building materials of the second type

In this case, the following sequence of operations is carried out:

• due to the mixing of the ingredients, a chemical reaction occurs, due to which pores appear;
• Finished products are processed in a specialized autoclave in order to increase their strength.

Such a product is mainly produced in factories, as there is a need for quite expensive and high-tech equipment. However, despite the cost of production, it fully pays for itself in the form of high quality blocks that are almost ideal in terms of geometry. Practice shows that masonry using materials of this type can be called ideal and takes a minimum amount of time.

What ingredients are included?

It is gas silicate products that repel many builders by the presence of aluminum powder, but in the end it is not contained in finished blocks. Meanwhile, these types of cellular concrete are perfect not only for the construction of houses in which you plan to live, but also for other buildings.
The composition of the foam blocks mentioned above includes ingredients of this format:

• blast-furnace slag and other types of waste from production processes;
• water;
• lime;
• cement;
• lye, and both soapy and sulfide lye are suitable.

The last ingredient - lye - is mandatory, because it is he who gives the material the necessary porosity.
Aerated concrete in accordance with regulatory documentation consists of:

• quartz sand;
• cement;
• water;
• aluminum paste;
• lime.

It is aluminum paste that worries buyers of such building materials, but it harms only in its pure, independent form. The manufacturing process almost completely dissolves its particles.

Obvious differences in structure

The pores of the gas block are much smaller than those of its foam counterpart. The surface color of the first one is white, and to the touch the surface seems to be rather embossed and rough. At the same time, its competitor has a smooth gray surface. Therefore, we can conclude that the differences between these products are visible even to the naked eye.

Structure defines properties

Since foam concrete is a material whose pores are closed, in itself it has good properties of both sound and heat insulation. In addition, it practically does not absorb water, but this does not mean that it will not need an exterior finish. Aerated concrete blocks have small pores in which microcracks are present. Because of this structure, the masonry will be exposed to active moisture. To avoid the negative consequences of the manifestation of this feature of the building material, it is necessary to cover the masonry with a special substance that can protect the blocks from water.

As for the strength of analogues, conclusions can only be drawn in practice. Indeed, theoretically, the density is proportional to strength, but in fact, aerated concrete, which is weaker in theory, is practically not inferior to its competitor. Specialists in the construction industry argue that in the field of practical use, it is gas blocks that are more durable and therefore their use in the process of erecting durable buildings is more relevant. However, the monetary costs of such work will also increase.

Aerated blocks, in view of their structure and composition, do not differ in very high thermal insulation properties. But due to the excellent geometry of the products, the frost resistance of the masonry can be significantly increased due to cement-adhesive compositions. In addition, the solidity of the masonry is ensured, which also minimizes the so-called "cold bridges".
It is believed that foam blocks have much more attractive thermal insulation properties. But in order to ensure decent indicators of heat conservation, it is necessary to build walls that are neither more nor less than two times thicker than gas-block ones. The conclusion is this: with an equal wall thickness, it is aerated concrete that wins.

Applications

Blocks from materials of both categories are used mainly in the construction of buildings with a small number of floors. Foam concrete is suitable for:

• load-bearing walls not higher than the third floor;
• partitions;
• various partitions.

At the same time, more durable and expensive aerated concrete is used for:

• creating partitions;
• construction of load-bearing walls;
• filling voids between the frames of monolithic buildings.

In addition, compacted with a stiffening belt, the blocks of such a product are also suitable for buildings above three floors.

The main question is the value

Often, it is the cost of the product that largely determines the choice of the buyer. Therefore, it is very important to explore this aspect in order to objectively answer the question “What is better to use a foam block or a gas block for construction?”.

The complexity of creating gas products in this category, among other things, lies in the need to use special equipment, the price of which often exceeds one hundred thousand dollars. Foam block products, at the same time, are often made hardly in the field, and often even at the construction site.

Thus, a quite obvious and expected conclusion suggests itself: gas blocks will cost much more than their counterparts. However, do not rush into making a decision in favor of foam concrete products. The fact is that the money spent should be fully paid off at least by the durability of the structure, the simplicity of construction work and the minimum consumption of related building materials. All this is provided just in the event that you choose gas blocks. The almost ideal geometry of products of this type reduces the duration of construction activities to a possible minimum, and the use of a special adhesive significantly improves masonry in all existing parameters. Other experts speak in favor of the foam block. They argue that by taking the time to choose products with proportional parameters, builders will be able to create almost the same building, but at a lower cost, not to mention the incredible savings during the heating season.

Gas block or foam block which is better than building for a house updated: December 14, 2016 by: Artyom

When talking about aerated concrete and foam concrete blocks, you can often encounter the fact that not everyone understands well what kind of materials they are and what is the difference between them. Aerated concrete and foam concrete are united by the fact that they belong to cellular concrete, i.e. have a porous structure. This provides them with high performance in terms of thermal insulation properties, ease of processing and use, good strength and reliability, and, most importantly, a relatively low price - after all, a brick wall will cost much more. But aerated concrete and foam concrete also differ from each other, which is due to some differences in their manufacture, hence the difference in some technical properties. It is impossible to say exactly which material is better, but we hope that after reading this material you will form the correct conclusion for yourself.

Features of the production of foam concrete blocks

The most important differences between foam concrete and aerated concrete should be sought in the technology of their production.

So, foam concrete blocks are obtained by adding special foaming additives of organic or synthetic origin to an ordinary cement mortar. Foam is formed on the basis of water, and the water itself evaporates naturally during the drying process. Foaming additives foam the concrete, thereby filling it with air bubbles. Such bubbles are distributed throughout the entire volume of concrete, and after hardening, they make it much lighter, adding heat-insulating and sound-proofing properties.

Such a process can be carried out right at the construction site, since especially specific and high-tech equipment is unnecessary. Due to the shapes used in the manufacture of the foam block, finished products may differ in size, sometimes by 10-20 mm.

Features of the production of aerated concrete blocks

To obtain aerated concrete, quartz sand, lime, cement and water are required, as well as a special component - aluminum powder, due to the presence of which bubbles are formed that fill the aerated concrete. The process of solidification of the mixture takes place in autoclaves at a sufficiently high temperature and high pressure, and not in natural conditions, as is the case with foam concrete. And since special equipment is used for production, all the characteristics of the future aerated concrete block can be controlled, making them the same throughout the entire volume. This cannot be said about foam concrete, which, while hardening on the street, may have a slightly heterogeneous and unequal structure and properties. And the shape of the gas blocks produced in this way is ideal, has minimal deviations from each other, which cannot be said about foam concrete, for which forms are often used that are not capable of ensuring accuracy and evenness.

Such processing allows aerated concrete blocks to have a number of other advantages over foam concrete, which we will discuss later.

Advantages of aerated concrete over foam concrete

1. Strength- this is the main advantage of aerated concrete. With the same density, aerated concrete is much stronger than foam concrete. And if we compare blocks with the same strength, then, naturally, aerated concrete will have a lower density, which means it will be easier and more convenient in construction. By the way, it is believed that foam concrete can shrink and microcrack after construction is completed, so it is useful to wait at least a year after building a house from foam concrete blocks before starting expensive repairs and decoration.
2. Aerated concrete blocks have the best vapor permeability. It's all about, again, the structure of the material and the method of production. So, in aerated concrete, all the pores are interconnected, which cannot be said about foam concrete, where they are isolated. Therefore, the aerated concrete block passes moisture and air better, and the microclimate in such a house will be much better than if you use foam concrete, which passes air much worse. That is why, if you decide to insulate a wall of aerated concrete blocks, then it is better to use breathable materials so as not to negate all the advantages of aerated concrete. And foam concrete blocks can also be insulated with foam plastic to reduce the cost of work.
3. Now oh thermal conductivity. It is believed that aerated concrete and foam concrete are capable of providing approximately equal thermal insulation performance. But if you look into some details, you can understand that the thermal insulation of foam concrete does not always meet the values ​​declared by the manufacturers. The fact is that the pores in foam concrete, as a rule, are of different sizes: they can be 1 mm, or they can be 5 mm, while in aerated concrete the pore size is usually constant. It follows from this that the value of thermal conductivity may differ in different places of the block. But this is not as scary as the fact that under conditions of high humidity, the thermal conductivity of foam concrete can increase significantly, which will lead to the fact that the walls simply will not keep the temperature that is comfortable for residents. Yes, and more powerful wall insulation will also have to be spent. Although there are many experts who can argue with this fact.
4. Aerated concrete blocks are often called environmentally friendly material - this is true, because in the production they do not use anything other than natural materials, which have already been mentioned above. In the production of foam concrete blocks, synthetic blowing agents can be used, which can no longer be called environmentally friendly. Here it is impossible not to mention the myth that aerated concrete contains aluminum, and it is harmful to our health. It is pointless to argue about the harmfulness of aluminum - it is harmful, but is it available in ready-made aerated concrete blocks? All the aluminum reacts with the lime, eventually liberating oxygen and forming aluminum oxide: oxygen is needed to form pores, and aluminum oxide is harmless and is found in most building materials, even in clay. Yes, and the aluminum oxide itself in aerated concrete is less than in foam concrete and in brick. And here, not everything is clear: there are opinions that aluminum still remains in the material, not completely spent on the reaction, but still we remain of the opinion that aerated concrete is more environmentally friendly.
5. The form aerated concrete blocks are almost perfect, and the error is no more than 2 mm, so it is very easy to work with them, the walls are smooth, and you need a little glue. Foam concrete blocks can have such significant deviations in size that it will be noticeable to the naked eye, and it will be more difficult to correct such irregularities, much more mortar will be needed.
6. Mounting aerated concrete blocks will cost you relatively less than foam concrete. This is due to the fact that glue is used for laying aerated concrete, and its thickness is much less than the thickness of the cement mortar for foam concrete (2 mm versus 1 cm). Even taking into account that glue is 2-3 times more expensive than cement, and its consumption will be about 6 times lower, we get savings, not to mention the fact that when using glue for aerated concrete, there are practically no cold bridges, which makes the house more comfortable and warmer.
7. Aerated concrete blocks are much easier in the subsequent decorative processing, this is largely due to the fact that they have excellent geometry.

Advantages of foam concrete over aerated concrete

conclusions

From everything written above, it follows that, according to some characteristics, foam concrete and aerated concrete blocks are similar, while foam concrete is cheaper. Thus, foam concrete may be suitable for a certain type of construction, where some of its shortcomings will not fail. Aerated concrete, on the other hand, has more attractive properties compared to foam concrete: largely due to production technology. And besides, if you count all the installation costs, then the construction of aerated concrete blocks may not be more expensive than the construction of foam concrete blocks. The final choice is made by everyone before the start of construction, but in most cases the use of aerated concrete blocks remains justified.

Cellular concretes are generated by the following circumstances: Firstly, for low-rise buildings, the strength, density and labor intensity of bricks, and even more so of reinforced concrete, are definitely excessive, and the heat and sound insulating properties are also definitely insufficient. Secondly, any known methods of wood processing guarantee the durability and fire resistance of a wooden building for more than 30 years only under especially favorable operating conditions. Therefore, attempts to bring the properties of concrete closer to wood by creating voids or heterogeneities in it were made back in the first half of the 19th century, and at present there are more than 10 types of cellular concretes. Foamed concretes are the most popular and promising, but the situation with them is not at all simple. .

In Internet sources on the question: which is better, foam concrete or aerated concrete, the confusion is unimaginable, and in some cases clearly malicious. The construction sites of some neighboring countries are especially guilty of this. It is difficult to understand what is an egg and what is a chicken, but the typical situation is as follows: there is, for example, a site on which a fairly objective comparative analysis of both materials is given. But! The properties of foam concrete are attributed to aerated concrete, and vice versa. That is, if “foam-” and “gas-” are interchanged, everything will correspond to reality.

Next to the text, contextual advertising and links to suppliers are intrusive. Walk through them - they name their goods correctly. Suddenly, an ignorant buyer, guided by what they read, orders and pays, they will bring completely different material to the site. And, as they say, there are no edges: suppliers with publishers are not responsible for each other, and you can also push back on advertisers. Therefore, it is imperative to figure out which of these two varieties of cellular concrete is better for construction.

Note: from other types of cellular concrete, we will touch on a little more expanded polystyrene concrete; it’s not that they lie about him, but they are silent about something significant. And with expanded clay concrete, wood concrete, fiber-reinforced concrete, etc., there seem to be no serious misunderstandings.

Where is the confusion?

Sources with the force of law, authoritative or at least claiming to be objective, from SniPs and polytechnic dictionaries (construction, explanatory, encyclopedic), to Wikipedia, give a clearly visible criterion for distinguishing foam concrete from aerated concrete. In the first, the pores are through, tortuous, irregularly shaped; in the second - rounded closed, see fig. But within each structure, the difference in properties and quality of the material is possible more than in different structures. Simply: good foam concrete can be better than aerated concrete suitable for use. And another significant point: the initial characteristics of both of these materials change in different ways and manifest themselves during operation, see below.

Why so, we'll see. In the meantime, it is simply necessary to clarify the scale of the discrepancies we are talking about. Otherwise, it is impossible to objectively assess the pros and cons of foam and aerated concrete: there is a lot behind the dry numbers in the tables, which, in fact, this article is about.

For example: you may have heard about the real estate situation in Spain. There, according to the state program of saving unlucky developers from bankruptcy, about 800 thousand new (!) Individual residential housing constructions were put up for auction. The prices are amazing. Here, for example, is the wonderful resort area of ​​Costa Calida. Granada, with its Alhambra and the skiing delights of the Sierra Nevada, is within easy reach. And - a villa for sale in 100 residential squares on the 2nd beach line (3-10 minutes walk to the sea). The architecture is neo-Andalusian, there is a swimming pool. The price of this paradise is 200,000 euros, 2,000 euros per square. By local standards, this is not at cost, but for how much they will take.

Why? We look at the specification: the structural material is a gas-block of a Euro-certain standard. What kind of euro is this? We search, with difficulty, but we find. Ah, understandable! Eurotakoito is a surrogate aerated concrete (see below for more details). We compare the dates: there are only 12 euros left in this building until the end of its estimated service life of 20 years. Who will give at least a Russian nickel for a house that is guaranteed to dilapidate in less than 15 years? Will they rent it for a porn studio or a brothel, but for a million establishments of this kind, this is a bit too much for Spain.

Here is another kind of example. In the zero-tenths, a thorough revision of the foam concrete buildings of the USSR of the 30s-50s was carried out. It turned out that 95% of the buildings gained strength two or three times (!); their other characteristics have not deteriorated. These buildings are recognized as fit for use after cosmetic repairs; Based on the current state, a second revision is scheduled after 80 years. 5% dilapidated due to violations of the rules for the production of work during construction. Given that under Stalin, forced labor of unskilled labor (prisoners) was widely used in construction, it must be admitted that the foam concrete of that time withstood the grossest violations of construction technology, except for completely unacceptable ones.

We are again looking for why. The answer is simpler: the bulk of the material is Portland cement with quartz sand; foaming agent - natural protein (more on this below). This is how the Costa Calida comes out.

Stamps

Foam and aerated concrete is produced / manufactured in the following grades; the numbers mean the mass density of the material ready for use:

1. Heat-insulating, not able to bear the load - D200-D400 for foam concrete and D200-D300 for aerated concrete;
2. Heat-insulating and structural, from which partitions and enclosing structures can be installed - D400-D800;
3. Structural, for the construction of load-bearing building structures - D900-D1200.

Note: it can be seen from here that the first 2 groups of marks and partially the 3rd are lighter than water.

Production

To understand the clearly inconsistent situation described above, you must first understand how the production of foam concrete differs from aerated concrete. Key points here:

• How to create voids in a material; simply foaming.
• For aerated concrete - the conditions for holding the batch until it hardens.
• Composition and properties of the main (bearing) material.
• The method of molding building modules.

Foaming

It is the method of formation of voids that is the main difference between foam concrete and aerated concrete. Foam concrete is obtained by introducing organic blowing agents into water for kneading. They are, firstly, from animal protein: the first samples of foam concrete were obtained by adding bovine blood to a cement-sand mortar. Secondly, based on saponins - substances that foam more strongly than soap, but with a neutral chemical reaction. Saponins were first obtained from plants of the Sapota family (soap root, etc.), but now they are almost completely replaced by synthetics, which are much cheaper than natural extracts.

Protein blowing agents provide practically unlimited durability of the building - remember the old buildings, for which eggs were added to the masonry mortar. But with the current situation with animal protein in the world, protein blowing agents are very expensive and there are almost no foam concrete on protein for sale. Saponins guarantee the relative stability of masonry characteristics for 40-70 years, and then its strength, moisture resistance and vapor permeability also steadily and quickly fall. The introduction of those and other blowing agents into the solution is possible directly on the site, i.e. foam concrete can be monolithic. Saponin foam is low- or medium-fold, so the spread of the initial parameters of foam concrete is quite large.

Aerated concrete is kneaded in a highly alkaline solution (quicklime is usually used) with the addition of aluminum powder. In this case, hydrogen is released, which, together with the main mass, creates high-expansion foam, due to which the initial characteristics of the material are maintained with high accuracy. The technological process is organized in such a way that the volume concentration of hydrogen in the air nowhere and never exceeds the explosive value of 4%. Due to the high diffusivity of hydrogen, it almost completely evaporates before the mass solidifies, and its residues subsequently flowing out are harmless and safe. But powdered aluminum and caustic alkalis are carcinogens and, the latter, toxins, of high danger groups. It is possible to ensure the safety of production processes with them only by laying it constructively in technological equipment; PPE can only be an addition.

Excerpt

Comparison of various brands of aerated concrete must also be made taking into account the method of holding the batch before technological hardening. The maturation of the foamed mass of aerated concrete is carried out either with heating without excessive external pressure (non-autoclaved aerated concrete) or in an autoclave under pressure (autoclaved aerated concrete). According to the initial characteristics, they may not differ much, but more expensive autoclaved aerated concrete gives buildings from it a service life of over 70 years, and non-autoclaved aerated concrete - up to 40-50 years. Frost resistance (the number of cycles of complete freezing / thawing before cracking) of autoclaved aerated concrete ranges from 80-100; non-autoclaved - up to 30.

The bulk

The main thing to pay attention to, if you intend to, is the composition of its bulk. The best results based on the results of operation are shown by mixtures of Portland cement and quartz sand; further, unless otherwise noted, we will consider cement-sand foamed concrete. However, a huge amount of foam and aerated concrete with a binder of slaked lime and a filler of ash from thermal power plants, ground industrial slag, etc., goes on sale. industrial waste, this is the so-called. surrogate concretes. Their durability and frost resistance are 1.5-2 times less than those of cement-sand foamed concrete of the same brand, but other initial qualities may not be worse.

Surrogate foamed concretes can be white, dazzlingly sparkling, like refined sugar, even if you put it in coffee. But the foamed mixture of Portland cement with quartz sand can also be white, like writing paper. Here the selection criterion is the specification of the material or just the marking on the package. Manufacturers of cement-sand foam and aerated concrete do not miss the opportunity to point out the dignity of their products, especially in the face of fierce competition, and suppliers of surrogates prudently keep silent about the origin of their goods.

Blocks and monoliths

Individual developers use foam blocks or gas blocks for work. Aerated concrete is made only in production conditions and is produced in standard modules. To knead foam concrete on the site, expensive purchased equipment is required, but all the same, the spread of material characteristics is more than acceptable. Therefore, monolithic foam concrete is made on site only of low grades; mainly for insulation and, rarely, enclosing structures. Videos give an idea of ​​​​how to produce foam and gas blocks:

Video: production of foam concrete blocks

Video: production of aerated concrete blocks

Note: introductory videos. Depending on the production equipment used, those and other technological processes can differ significantly.

The dimensions of foam and gas blocks are maintained in a module of 300 mm; standard - 300x300x600 mm. Aerated concrete of low grades for thermal insulation is also produced in slabs in modules of 150 and 125 mm, for example. 1200x600x150 mm or 1250x500x125 mm.

Aerated concrete and foam concrete can be machined with a conventional steel tool, but the first crumbles weakly and only from shock loads, and the second crumbles strongly and, apart from shock, from uneven loads. Therefore, foam blocks are formed exclusively by pouring into molds. Saponin foam creates significant pressure, the forms are bursting, so the accuracy of manufacturing foam blocks is low: about 1% of resp. size. That is, the transverse dimensions of a standard structural foam block can "walk" by 3 mm, and the length - by as much as 6.

Gas-blocks are delivered for sale cast and cut. High-expansion hydrogen foam almost does not put pressure on the mold: the diffusion rate of hydrogen increases very quickly with an increase in its partial pressure, and excess gas simply escapes. The dimensions of cast gas blocks can be maintained with an accuracy of +/-1 mm. Sliced ​​gas blocks are generally fantastic for building materials with an accuracy of +/-0.5 mm, but they cost 5-15% more than cast ones, because. cutting tool wear and material waste cost money.

Jumpers, locks and weights

Due to the better ability of gas blocks to bear shock and uneven loads, together with higher manufacturing accuracy, it is possible, firstly, to lay the lintels of window and door openings in gas block walls from 150 mm (item 1 in the figure), while foam blocks require the laying of those the same structural elements from 300 mm. Secondly, gas blocks are also produced with shaped locks, pos. 2, providing greater strength and less heat loss of the building.

Then, only battens for sheathing can be fastened to foam concrete walls with steel fasteners, with dowels for hardware from 150 mm; under the concentrated loads it is necessary to put through anchors. A hook in a dowel with a depth of 120 mm in an aerated concrete wall holds a weight of up to 15-25 kg, depending on the brand of material. That is, in order to hang, say, a TV on a foam concrete wall, you will need to distort the finish in the adjacent room. There are no problems with aerated concrete, on the contrary: you don’t need a hammer drill and a drill for concrete, a hand drill without a vibrator and a conventional twist drill is enough. Respectively, and there will be less garbage.

Characteristics of foam concrete and aerated concrete

The most important performance characteristics of structural cellular concrete, red brick and building wood are summarized in Table. Some bewilderment may cause the required thickness of the wall, but it is calculated, firstly, for a bare wall, without interior and exterior finishes, cladding and insulation for -25 outside. Secondly, it is taken into account that the homeowner does not pay for energy overruns at an increased rate. And, to summarize, let's go over other essential lines of it.

Cost and shrinkage

Actual prices for the cost of 1 sq. m walls change, but their ratio remains approximately the same. However, the question may arise here: how is it that foam concrete is almost a quarter cheaper than aerated concrete, and a wall made of it is more expensive? In addition to the thickness of the wall, it also plays the role of a masonry seam. Gas blocks are placed only on special glue. A high-quality adhesive for aerated concrete costs 2-3 times more than a conventional masonry mortar, but the latter needs 3-5 times more in terms of volume (see the thickness of the seam).

Foam blocks can be laid seemingly on glue, but foam concrete greedily absorbs moisture, see below, and a fresh seam dries up before the next block is laid. In addition, the manufacturing accuracy of foam blocks is almost equal to the thickness of the glue line, which is unacceptable for reasons of strength.

Note: no need to estimate the estimated cost of construction at the price of a square wall. The total cost of construction depends on many factors, and, depending on local conditions, may be comparable in price or even cheaper than stone.

Further, small dry (own) shrinkage of aerated concrete occurs quickly, within a month, and you can start finishing. Foam concrete settles in a year, and technical breaks also cost money. To an individual developer - at least for renting temporary housing. Finally, due to chipping of foam concrete under uneven load, the bearing capacity of the foundation of a foam concrete house should be higher, and its shrinkage is less than under aerated concrete, i.e. and the foundation for foam concrete will cost more.

Humidity

Operational humidity means - how much by weight of water vapor the material is able to "suck" from the air. 5% or 15%, there is not much difference; e.g. for air-dry commercial wood, the moisture content is 20%. But the rate of absorption of moisture is another matter. It depends on the physical mechanism of moisture absorption: capillary or diffusion. The first is typical for foam concrete and wood, the second for autoclaved aerated concrete, and non-autoclaved aerated concrete absorbs moisture this way and that. In turn, the rate of capillary moisture absorption very strongly depends on the size of the cross section of the pores in the material.

Let's do a trace. experience: let's take pieces of foam, autoclaved and non-autoclaved aerated concrete and wood of the same size, shape and density, i.e. weight. Let them swim in a container of water. Foam concrete before our eyes will be saturated with water and sink. We continue the experiment, adding water as it evaporates. Non-autoclaved aerated concrete will float for 2 weeks - 3 months, but autoclaved aerated concrete will remain afloat even when the piece of wood has already gone to the bottom. Remember: aerated concrete dampens slowly and unimportant.

Vapor permeability

Here we compare foamed concrete with wood. Taking into account the fact that there are no wooden structures without ends in the air, it turns out that foam and aerated concrete "breathe" almost like a tree. And if we remember how autoclaved aerated concrete slowly gains moisture, then we come to the conclusion that it is almost better for a bath than a traditional tree. Moreover, its thermal conductivity is lower: the bath will warm up faster.

What is not in the table

We will complete the review of the properties of aerated concrete with some additional parameters:

• Cold resistance - F35, i.e. mechanical characteristics are maintained down to -35 Celsius.
• Fire resistance - class A1, withstands heating for 20 minutes up to 300 degrees without loss of strength.
• Permissible axial load of structural grades - class B2.5; It is permissible to erect walls up to 20 m high.
• Absolutely unattractive, unlike polystyrene concrete (see below) for rodents and insects.

About expanded polystyrene concrete

Expanded polystyrene concrete, or foam concrete, is not among the foamed concretes, but you need to linger on it. Recently, foam concrete has been heavily advertised, and there seems to be formal reasons for this: it is cheaper than aerated concrete and is not inferior to it in most parameters. But what foam-reinforced concrete enthusiasts don't talk about: its zero fire resistance, heating is not allowed. In a flame, expanded polystyrene concrete collapses catastrophically, shatters into pieces with a crash, and, like polystyrene, emits a large amount of extremely toxic gases.

Conclusion (and what not to)

What is not necessary is to mix the foamed concrete yourself. Fussing with aerated concrete components at home is simply dangerous to health, see above. As for foam concrete, there are plenty of stories about it on YouTube on the topic “with your own hands”. But you will be shown either the work of an expensive and requiring qualified maintenance of a purchased installation, or kneading in something like a basin or a bucket. Is it possible in this way to get cubes and dozens of cubes of quality material for construction - a rhetorical question. To knead from the components purchased at retail for the insulation of floors? "Spotted" in terms of thermal conductivity, insulation is worse than poor homogeneous insulation, because. causes mold and mildew. And for the price, ecowool insulation will be comparable, which in this capacity has a lot of its own advantages, but devoid of the disadvantages of foam concrete.

When erecting buildings, the question of the choice of building material almost always arises. In this article, we will consider two types of materials for building walls: foam blocks and gas blocks, and we will try to find out what to build a house from and which is better - foam block or gas block.

Production technology of gas blocks and foam blocks

These are two types of building materials that are made from different components and in different ways.

Foam blocks

Foam blocks are made of foam concrete - a porous material consisting of cement, sand, water and foam. Sometimes some other ingredients, such as ash, may be added to them. Acquires porous, thanks to the special chemical reagents that are part of the solution. This foamy solution is poured into special molds and, after hardening, finished products are obtained, including foam blocks. Due to the porous structure, foam blocks are lightweight, have low thermal conductivity and good sound insulation. This building material is very durable and strong.

gas blocks

Now, to answer the question of which is better - a foam block or a gas block, consider

Properties also have a porous structure and the same properties that are inherent in foam blocks, but they are made using a different technology. The composition of aerated concrete includes cement, lime, sand, aluminum powder and water. Pores appear when aluminum powder reacts with cement. The finished mixture is stirred and kept for a certain time until it acquires the desired condition. Then the resulting array is cut into blocks using special strings. Then they are placed in an autoclave, where all excess water evaporates from them, they acquire their final form and properties, and become ready for consumption. They are light and have good soundproofing characteristics, as well as foam blocks. Gas blocks have high strength and low thermal conductivity. These figures are slightly higher than those of foam concrete, but still it is not easy to determine which is better - a foam block or a gas block due to the many advantages of foam concrete.

Differences between foam blocks and gas blocks

In search of an answer to the question of which is better - foam block or gas block, it must be said that these materials have only one difference - the high hygroscopicity of aerated concrete. Foam concrete, on the contrary, has low hygroscopicity.

What is the best to build

Both materials have many similar benefits. So what is the best way to build a house? The foam block is just as good for this as the gas block. Both materials make excellent one-story and They have thermal conductivity indicators that compete with wood and in many ways surpass ceramic bricks. Since they do not contain harmful substances, they are environmentally friendly for humans. But gas blocks have one drawback, due to which it is inferior in efficiency to foam blocks - this is the complexity of the technology for building walls from this material, due to its hygroscopicity. Gas blocks are delivered from the factory with a high level of humidity, therefore, after the construction of the house, it is impossible to immediately carry out exterior decoration. It is necessary to wait several seasons until the walls are completely dry or to equip a ventilated facade, and this leads to an increase in construction costs. So, when determining which is better - a gas block or a foam block, the scales tipped towards the latter because of its efficiency.

Building materials with a porous structure are gaining popularity. They are durable and lightweight, used for the construction of private houses, country cottages, household and commercial buildings, garages. For this, foam concrete and aerated concrete are more often used, but you need to know what is the difference between these two concretes that are similar in technical characteristics.

Foam concrete and aerated concrete are building materials that are gaining popularity because they have sufficient strength and low thermal conductivity. The porous structure reduces the density and mass of blocks made from them. The air-filled cells explain the thermal insulation. Despite the similarity of characteristics, the scope of these compositions varies.

Strength, low specific density of foam concrete increases the service life of this material. Therefore, it is used for residential buildings - houses, cottages, household structures, baths. The only limitation in the use of foam concrete is that buildings erected from it should not be higher than three floors. It is used in the device:

• bearing walls of buildings and structures;
• interior walls for space planning;
• fences, fencing areas;
• floors with steel bar reinforcement.

The uniformity of the structure of aerated concrete explains one of its main features - increased resistance to cracking and shrinkage of structures created from it. This allows it to be used for the construction of household buildings, industrial, public and commercial facilities. It is used for:

• interior partitions;
• filling spans in frame buildings;
• load-bearing structures and walls;
• multi-storey structures and buildings.

Production technologies and composition

To understand how aerated concrete differs from foam concrete, you need to understand the technologies by which these building materials are made. During the production process, an internal porous structure is formed at the calculated density and strength - characteristics that determine the main advantages. At the same time, components that are harmless to health are used, which significantly expands the scope of such concretes.

Foam concrete production

Foam concrete is produced using a simplified technology, available even at home. The components for production are: cement, water, sand, slag and other fillers. The main substance - providing the porosity of the material structure - sulfite liquor. For foam concrete you will need: Portland cement 36%, sand 47%, 16% water. Foam additives and fibers to increase strength do not exceed 1%. Production stages:

1. All ingredients are thoroughly mixed in dry form, after which a small amount of water is added to them.
2. A foaming component is added - sulfite liquor. Stirring is continued until a homogeneous structure is achieved. During chemical reactions, gas is released, as a result of which the material acquires a porous structure.
3. The prepared solution is placed in the prepared formwork in the form of the required blocks or structures. Foam concrete sets in 10 hours, the minimum time is 5 hours. After removal from the formwork, the blocks are laid outdoors or in a dry room for final drying.
4. The necessary strength, allowing the use of this material, is achieved in 14-21 days.

It is important to pay attention to the quality of the formwork so that the dimensions and surface of the blocks or structural elements meet the technical requirements.

Aerated concrete production

Aerated concrete is produced at industrial enterprises with special equipment. Cement, quartz sand and lime, water are used as the main components. The foaming component is aluminum paste. The composition is similar to that used for the preparation of foam concrete. A pure substance carries an environmental hazard, but it is completely neutralized during the production process. Stages of production of aerated concrete:

1. The components are poured into the concrete mixer in proportions and filled with water, kneaded to a homogeneous consistency, according to a pre-developed technological map. The added aluminum paste, sometimes powder, reacting with the solution, saturates it with gas, creating a cellular structure and at the same time being neutralized.
2. The resulting solution is poured into pre-prepared forms. It should be borne in mind that as a result of the reaction of aluminum compounds, its volume will increase during setting.
3. The frozen monolith is removed from the molds and cut into blocks, slabs, lintels, and other elements of the desired size.
4. To improve the strength and waterproofing characteristics, the resulting products are processed in autoclaves under steam at 12 bar or high temperature electric furnaces.

The resulting aerated concrete and materials from it have increased strength, correct geometry.

Feature Comparison

The main components and production technologies are largely similar, but the technical characteristics of these materials differ. The difference between the properties of foam concrete and aerated concrete is explained by their structure and appearance.

Foam concretes are structured with relatively large cells with low moisture absorption, good sound and heat insulation. The surface is relatively smooth, the color is gray.

Aerated concrete has smaller cells, as a result of the formation of gas in the thickness of the solution, microcracks may appear on the surface. They have good water and vapor permeability, thermal insulation characteristics. Rough white surface requires additional finishing.

The density of aerated concrete is in the range from 400 to 800, foam concrete - a higher density from 400 to 1200 kg / m³. Differences in other specifications:

• Aerated concrete has more stable thermal conductivity, since it has a uniform cellular structure. The pores in foam concrete have a diameter of 1-3 mm, they are distributed unevenly, so the thermal conductivity of this material is unstable.
• The strength of treated aerated concrete is significantly higher than that of foam concrete.
• Industrial production makes it possible to obtain aerated concrete blocks with precise geometry; privately made foam concrete blocks do not have such properties.
• The plaster lies on both materials, but the correct geometry of the aerated concrete elements saves. Also, aerated concrete has better adhesion.
• Aerated concrete has better frost resistance, like autoclaved or heat-treated concrete. This indicator for foam concrete reaches 35 cycles of freezing and thawing, and aerated concrete with hydrophobic fillers can withstand up to 75 cycles.

If we compare the performance of foam concrete and aerated concrete, then aerated concrete has the best performance, allowing its use for the construction of various buildings and structures, including multi-storey ones.

Advantages and disadvantages

Aerated concrete and foam concrete have their own advantages and disadvantages. What is better to use in a particular situation can only be determined after analyzing the properties of these materials. Among the advantages of foam concrete note:

• Relatively low thermal conductivity.
• Relatively low density, which allows you to save on the foundation, lay out the walls yourself.
• High levels of sound insulation.
• The optimal size of blocks and other structural elements speeds up construction.
• Ease of fitting elements with a simple hacksaw.
• Environmental friendliness allows the use for the construction of any residential premises.
• Long-term operation even in difficult conditions, corrosion resistance.

But this material also has disadvantages:

• The porosity of the structure gives fragility, especially at the edges of structures, the strength of foam concrete is unstable.
• Unattractive outer surface, which is better to plaster.
• When erecting foam concrete structures, reinforcement is required at the junctions of elements.
• With handicraft production, the quality of the material is reduced.
• The use of this material requires careful calculations of the strength of the structure.
• Foam blocks do not have the correct geometry, since they are not produced in industrial conditions.

The advantages of aerated concrete include the following characteristics:

• Reduced density with increased strength.
• Increased moisture resistance of the autoclave block.
• Fire resistance.
• Frost resistance.
• Resistant to biological influences and corrosion.
• Durability allows buildings to operate for more than 100 years.
• Excellent indicators of heat and sound insulation.
• Ease of processing.
• Savings, since aerated concrete requires a minimum amount of cement.
• Environmental Safety.
• The correct geometry, since the structural elements are made in production.

With all the advantages of the material, it also has disadvantages:

• Increased hygroscopicity requires additional plastering.
• Accuracy is required when calculating loads, since blocks can crack.
• The cost of this material is higher than foam concrete.

Results

When choosing foam concrete or aerated concrete, you need to weigh what is best for construction. These materials have much in common, but there are differences that do not allow them to be used in the same way. Obviously, aerated concrete has the best strength indicators, they are similar in other characteristics. Therefore, specific calculations, features and budget of the work are taken into account, as a result of which a decision is made.