Sphere modern construction invariably pleases us with novelties, thanks to which the process of erecting buildings becomes less lengthy, and its result is the most consistent with 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 shortcomings.
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 the whole controversy about their differences is far-fetched and is nothing more than marketing ploy and therefore there is no need to argue that better foam block or gas block 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.
The entire production process can be divided into a number of operations:
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.
AT this case carried out next sequence operations:
| Comparison of the main physical and technical indicators of traditional building materials with foam concrete | ||||||||
| Indicators | unit of measurement | Building brick | Building blocks | foam concrete | ||||
| clay | silicate | expanded clay concrete | aerated concrete | |||||
| Density | kg / m 3 | 1550-1700 | 1700-0950 | 900-1200 | 600-800 | 200-1200 | ||
| Weight 1m 2 walls | kg | 1200-1800 | 1450-2000 | 500-900 | 200-300 | 70-900 | ||
| Thermal conductivity | w/m 2 | 0,6-0,95 | 0,85-1,15 | 0,5-0,7 | 0,18-0,28 | 0,05-0,38 | ||
| Frost resistance | cycle | 25 | 25 | 25 | 35 | 35 | ||
| Water absorption | % by mass | 12 | 16 | 18 | 20 | 14 | ||
| Compressive strength | MPa | 2,5-25 | 5-30 | 3,5-7,5 | 2,5-15 | 2,5-7,5 | ||
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.
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:
The last ingredient - lye - is mandatory, because it is he who gives the material the necessary porosity.
Aerated concrete according to regulatory documentation comprises:
It is aluminum paste that worries buyers of such building materials, but it harms only in pure, independent form. The manufacturing process almost completely dissolves its particles.
Aerated concrete products are more diverse
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 surface gray color. Therefore, we can conclude that the differences between these products are visible even to the naked eye.
| Parameter | aerated concrete | foam concrete |
| Thermal conductivity coefficient, W / mx o C | 0.10-0.14 | 0.0-0.38 |
| Bulk weight, density, kg / m 3 | 400-800 | 400-1200 |
| Compressive strength class of concrete | Class B2.5 at D500 | Class B2.5 at D750 |
| Vapor resistance, mg / mchPa | 0.2 | 0.2 |
| Water absorption,% by weight | 20-25 | 10-16 |
| Frost resistance not less than | 50 cycles | 25 cycles |
| Masonry … / masonry joint thickness, mm | Tlieo for glue / 2-3 mm | For glue, mortar / 10 mm |
| Average shrinkage of finished masonry | 0.3 mm/m | 2-3 mm/m |
| Average thickness of a single-layer wall, m | 0.4 | 0.63 |
| Soundproofing | Worse | Better |
| Pore structure | Closed | open |
| Appearance | Better | Worse |
| Average self-delivery cost, rub./m 3 | 3100.00 | 2500.00 |
| Grade by density | D350, D400 … 700 | D400 … 00, D1000 … 1200 |
| Possibility of masonry reinforcement | There is | Not |
Since foam concrete is a material whose pores are closed, it itself has good properties both sound and thermal 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 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.
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:
At the same time, more durable and expensive aerated concrete is used for:
The use of foam concrete involves exterior finish building In addition, compacted with a stiffening belt, the blocks of such a product are also suitable for buildings above three floors.
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.
Perhaps the differences are far-fetched 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, simplicity construction works and minimal 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 better construction for home updated: December 14, 2016 by: Artyom
Modern trends in the construction of private houses require the replacement of traditional brick and wood with more technologically advanced materials. It remains only to decide: foam concrete or aerated concrete, which is better?
1. Foam and aerated concrete have a low specific gravity, they are lighter than other materials. And this factor is decisive when choosing a material for buildings on lightweight foundations.
2. Unlike brick, masonry is built quickly, such work does not require high qualifications.
3. The non-susceptibility of these materials to corrosion or decay allows them to be connected to structures made of other materials using metal fasteners.
4. Any concrete products are not of interest to insects.
5. Fire safety is also an important thing.
6. Even if the design of the house was completed with errors, they are quite easy to eliminate in the walls of cellular concrete. So, in order to cut out just one niche in the wall from monolithic concrete for an outlet, you will have to spend up to five hours. During the same time, it is possible to mount in the living room in full concealed wiring. Provided that the walls are made of cellular concrete.
Along with general positive characteristics, the use of a particular material is due to its characteristics. Before making your choice: which is better, foam or aerated concrete, you should familiarize yourself with their characteristics, comparing them to solve a specific problem.
In order to make blocks, it is enough to have an ordinary concrete mixer and a simple foam generator. The entire production process is easily organized directly on the plot.
In order to prevent the foam from settling, the mass, which was formed into blocks, is subjected to autoclaving. Long-term processing at a temperature of about 200 degrees and high (up to 14 atmospheres) water vapor pressure ensure the formation of a petrified block structure.
Such production requires industrial conditions. But in mass production it is possible to produce blocks in large volumes. At the same time, they will be of the same size and with identical mechanical properties.
The method of fastening the blocks during their laying is determined by the specifics of their manufacture. So, for fastening foam concrete blocks, the usual cement mortar, and for bonding aerated concrete, the use of special glue is required.
In order to answer the question: what is better, foam concrete or aerated concrete, you must first answer the question: what is “good” in general. In some cases, the individual properties of each of the materials are useful, sometimes they make these materials indispensable. related to each other, they are united by a common concrete base. Therefore, they have the following general useful properties: The only drawback of both materials is their high ability to absorb moisture. This negatively affects the thermal insulation qualities of materials, and negative temperatures threaten to destroy the structure of the material. However, this disadvantage can be easily eliminated if the surface is simply revetted.
It is conditionally possible to highlight the advantages and disadvantages of each of these materials in comparison with each other:
Flaws:
1. Great cost;
2. Higher ability to absorb moisture;
3. The worst soundproofing properties.
Flaws:
1. Lower thermal insulation properties;
2. Worse block geometry;
3. The inability to reinforce the masonry;
4. Shorter service life (up to 30 years);
5. The material is heavier (has a higher specific gravity);
6. Less masonry strength;
7. Creates a large load on the foundation;
8. Subject to shrinkage;
9. More difficult to process;
10. More susceptible to low temperatures.
To evaluate the remaining features of cellular materials, it is necessary to understand all the conditions of application in specific conditions. It would seem even obvious.
The cost of shipping the material is another not unimportant component. Cellular blocks cannot be stored under open sky due to the threat of precipitation. Therefore, they must be used immediately. And foam concrete blocks can be made right on the spot, as needed during installation.
The device of cold bridges, which are common for a cement screed, is unacceptable for an adhesive joint. But this is only a disadvantage for external walls that are not trimmed. Considering that for any wall made of cellular material, finishing with plaster or siding is provided, this factor does not really matter.
They have standard sizes, the accuracy of their implementation is up to 1 mm. This circumstance helps to significantly facilitate the laying of flat walls and significantly reduce the consumption of glue. Gas blocks are made strictly in the form of a parallelepiped. Foam concrete blocks can have any shape, as they are made independently. The result is the possibility of making walls in the form of rounded, and sometimes even more complex profiles, made in the form of complex architectural elements.
There is an opinion that foam concrete is not environmentally friendly. As an argument, the use of foaming agents of synthetic origin in the manufacture is given. However, if you enter a query in search engines: aerated concrete houses reviews of the owners, it will be possible to make sure that this material does not pose any threat to human health. Moreover, these people have the opportunity to select specific drug. A wide range of such drugs is offered on the market, they have a different composition and cost. It is also necessary to take into account the fact that when buying ready-made blocks of aerated concrete, the consumer does not have confidence in their quality and sanitary safety.
The creative space when using cellular concrete materials is limitless. It remains only to wish the owner of the house to plant a tree and raise a son in it!
Gas and foam concrete blocks are related building materials. They are made from lightweight cellular concrete. These two types of blocks are actively used in low-rise construction. Often, developers have a question, what material is better to use?
Choosing foam or aerated concrete will help knowledge about the method of their production and characteristics. They will be discussed in this article.
One of the main advantages of a building material is its strength. This parameter directly depends on the density (specific gravity) of concrete:
Based on these figures, foam concrete blocks should be more durable. However, it is not. Aerated concrete building material is manufactured by the factory method and with the help of modern technologies. Due to this, with a strength of 35 kgf / cm² and a density of 450 kg / m³, it can withstand the same loads as foam concrete with a specific gravity of 650 kg / m³.
Both building materials are considered warm. But which one has the highest rate?
Aerated concrete blocks have lower cold resistance than foam blocks. However, their geometry is perfect. Thanks to this, this material can be placed on a very thin layer of glue. Because of this, there is a minimum number of cold bridges.
For comparison:
For the last material high level thermal resistance, it effectively accumulates heat. This makes it possible to reduce the cost of heating the home. However, in order for such a result to become possible, the thickness of the foam concrete walls must be twice as large as that of the enclosing structures made of gas blocks.
From this follows the conclusion: aerated concrete buildings warmer (2 times) than foam concrete, with the same thickness of enclosing structures.
Desired qualities of building material for walls:
Foam and aerated concrete blocks have all these qualities. However, there are differences between them.
One of them is in the geometry of the blocks. Aerated concrete material is manufactured only in the factory. Therefore, it has almost correct form. As a result, gas blocks are more convenient to lay, and masonry mortar spending less. Foam concrete material is often made handicraft, because of this, its geometry leaves much to be desired.
There are differences in the block production technology. Aerated concrete analogues are environmentally friendly. In the manufacture of foam concrete, production waste is often used to replace quartz sand. Moreover, lye or waste left after leather dressing is used to produce foam. Because of this, the blocks have a reduced shelf life, and the properties of this building material are unstable.
Foam blocks are made simply. This makes it possible to produce them handicraft. The mixed solution is placed in molds in which it hardens. Very often the shape of the material comes out uneven.
There are differences in the storage conditions of building materials. Aerated concrete building material again wins in this, as it is reliably packed. Due to this, it is protected during storage from atmospheric influences and pollution. Foam concrete analogues are not packed. This is their minus.
The material for the production of both types of blocks is lightweight concrete, the structure of which is permeated with small pores (cells). The conditions of production and the ingredients used influence the quality of these related building elements.
Their production methods differ, cells are formed during various production processes.
Foam concrete blocks are made like this:
The equipment for their manufacture is inexpensive. Therefore, foam concrete blocks are often made in small workshops. Due to the wear of forms, products often have irregular geometry. The difference in dimensions can be significant, and this reduces the quality of the masonry.
Features of the production of aerated concrete blocks:
Properties due to which it is worth choosing aerated concrete blocks for construction:
For the production of foam concrete blocks, hydrated lime, water, Portland cement, blast-furnace slag, etc. are used. Sulfide or soap liquor is used to foam the mixture.
Aerated concrete is made from Portland cement, quartz sand, slaked lime and water. Aluminum paste is used as an additive. This ingredient is harmful to health, however, during the production of the material, its particles dissolve.
In foam concrete, the structure is obtained with closed cells. The walls come out of it warm and have good sound insulation. The material absorbs less moisture than aerated concrete. However, it is still necessary to veneer the walls from it.
In aerated concrete, the structure consists of small pores and microscopic cracks. It absorbs water more intensively than foam concrete. Therefore, aerated concrete walls must be protected with a moisture-resistant cladding.
An important selection criterion is the cost of blocks and, based on it, the price of construction. Equipment for the production of gas blocks is expensive, and the production technology is complex and costly. Therefore, aerated concrete blocks are not cheap. They cost 3000-3500 rubles per cubic meter.
Equipment for the production of foam blocks is several times cheaper. The technology of their manufacture is simpler. Thanks to this, the material costs 2500-2900 rubles per cubic meter.
Aerated concrete blocks are more expensive than the foam counterpart. However, due to their ideal geometry, masonry mortar is spent on them much less, and the walls are more durable.
Before choosing a building material, you should know about the scope of its use. Autoclaved aerated concrete blocks in most cases are used for the construction of enclosing structures, as well as internal partitions in domestic construction. In addition, with their help, frames are filled during the construction of monolithic buildings. The material can be used in the construction of high-rise buildings.
At foam concrete blocks natural drying the scope is not so wide. The scope of their use:
For the construction of residential buildings up to two or three floors high, private cottages, summer cottages, aerated concrete blocks are often used.
What building material to choose for the construction of a garage, utility and other non-residential buildings? Blocks for them must be strong, reliable, durable, resistant to mechanical stress. Aerated concrete meets these requirements, however, for reasons of economy, it is better to prefer foam concrete. Its characteristics are quite suitable for the construction of non-residential buildings.
If you need to build a bath, it is better to choose foam blocks. Aerated concrete is warm and well soundproofing rooms, but it is less moisture resistant, quickly absorbs water and dries for a long time. Therefore, it is undesirable to use this building material for a bath or sauna.
Foam concrete has better moisture resistance, it is cold-resistant. Therefore, it is ideal for the construction of a bath.
The choice in favor of gas or foam concrete blocks depends on their characteristics, features and cost. It is easier for amateur builders with little experience to work with the first type of product. They have standardized sizes, high quality and good specifications. Foam concrete blocks can have uneven surface but they are cheaper.
Watch the video posted in the article. It contains a lot of additional information on what criteria should be used to choose a building material:
When planning to build a house, it is important to immediately do right choice main building material. The strength of housing and a comfortable microclimate depend on what you will build a building from. Walls should be created from environmentally friendly raw materials, which have low sound and heat conductivity, as well as fire-fighting properties. To make the final choice, which is better, let's compare two modern and popular materials and choose which is better - aerated concrete or foam concrete.
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foam concrete |
aerated concrete |
Production technology. The technologies used and the raw materials used are the main difference between the materials under consideration. Foam concrete is obtained by mixing cement, sand, water and foaming additives, which can be of both organic and synthetic origin. The mixture is poured into molds or immediately into the formwork and hardens in natural atmospheric conditions.
What is better - aerated concrete or foam concrete, can be judged if we understand the fundamental technological difference between these materials.
Quality stability. Aerated concrete is created in the factory according to GOST, while foam concrete can be obtained directly at the construction site where the house is being built, that is, in a handicraft way. Despite some advantage of foam concrete blocks in terms of financial investments, the quality of such material cannot be properly controlled.
Strength. If we compare blocks of the same density, foam concrete in its physical properties and strength significantly loses to aerated concrete. For the first building material, its performance depends entirely on the quality of the materials used in the manufacture. And here we must take into account that manufacturers, in their desire to reduce the cost of production, often save on foaming agents, the quality of cement and sand.
Dry shrinkage. The shrinkage of foam concrete during drying is higher than that of autoclaved gas blocks, and is 1–3 mm/m. Therefore, the risk of cracks appearing on the wall of the house over time when laying foam concrete blocks is higher, while the corresponding indicator for aerated concrete blocks does not exceed 0.5 mm / m.
Environmental friendliness. Another important difference between aerated concrete and foam concrete is safety from an environmental point of view. Since the second material can be produced from crushed stone waste and chemical additives, its environmental performance is lower. Aerated concrete, which is created from mineral raw materials, is also impeccable in this regard. In addition, it has better vapor permeability compared to foam concrete, so housing built from it will have almost the same favorable microclimate as in a wooden house.
Geometry. Accuracy geometric dimensions foam concrete products can be broken due to the simplified production technology of this material - deviations in linear dimensions can be even 2 cm. The geometry of aerated concrete blocks is regulated by GOST, and tolerances insignificant and can be up to 2 mm, so the masonry is almost perfectly even.
Water absorption. Foam concrete manufacturers love to demonstrate simple experience. If you throw such a block into the water, it will stay on the surface for a long time. The same will happen with aerated concrete. Then what's the difference? Both materials have a porous structure, so they will still absorb approximately the same amount of moisture. But if there are only closed pores in foam concrete, then in aerated concrete blocks- closed and open. Thanks to open pores, aerated concrete is able to give large quantity moisture.
thermal insulation properties. This parameter is affected by the structure of the block. The more uniform it is, the warmer the material. The structure of aerated concrete is more uniform than that of foam concrete, so the former has the best indicators of strength and thermal insulation.
Building a house from foam concrete or aerated concrete will cost much less than building from traditional brick. Cellular concrete - lightweight material, therefore, the creation of a massive foundation is not necessary, a lightweight construction is quite enough.
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foam concrete |
aerated concrete |
The use of such materials allows you to reduce the thickness of the walls, which means that less building materials will be required. Large block sizes will allow you to spend on masonry less solution and speed up the process. The reliability of foam concrete and aerated concrete lies in their incombustibility, which cannot be said about buildings made of wood and timber. However, due to the worse thermal insulation properties of foam concrete at equivalent densities, it will need 2-3 times more than aerated concrete to ensure thermal comfort at home.
Having considered the differences between aerated concrete and foam concrete, we can say with confidence that the first material wins in terms of its quality characteristics.
| Characteristic | aerated concrete | foam concrete |
|---|---|---|
| Coefficient of thermal conductivity | 0,084-0,147 | 0,22-0,37 |
| Grades by density | 300, 400, 500, | 600, 700, 800, 900 |
| Strength | Class B2.5 at D400 | Class B2.5 at D700-800 |
| Vapor permeability | Aerated concrete is higher than foam concrete at the same density | |
| Deviations of geometric dimensions | +/- 1 mm | Up to 30 mm |
| Masonry, joint thickness | Glue laying. Seam 1-3 mm | For sand-cement mortar. Seam up to 16mm |
| Foundation | Foam concrete has a higher specific gravity, therefore, with the same strength, the load on the foundation of foam concrete is higher | |
| Mounting | Because foam concrete blocks are heavier, it is more difficult to carry out work on the construction of a wall and their further finishing with them | |
| Material Handling | Foam concrete blocks are more dense and uneven in structure, so they are more difficult to saw | |
| Durability | Over 100 years | About 50 years |
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 wood processing methods guarantee durability and fire resistance. wooden building more than 30 years only in especially favorable conditions operation. 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.
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 pores through, tortuous, irregular shape; 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? Let's look at the specification: structural material- a gas block of a euro-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 current state, a re-audit 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.
Foam and aerated concrete is produced / manufactured in the following grades; the numbers mean the mass density of the material ready for use:
Note: it can be seen from here that the first 2 groups of marks and partially the 3rd are lighter than water.
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:
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 stronger 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 precision. 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.
Comparison of various trademarks aerated concrete must also be produced taking into account the method of holding the batch until 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 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.
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:
Note: introductory videos. Depending on the production equipment used, both technological processes may 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. wear cutting tool and the waste of material costs money.
Due to the better ability of gas blocks to bear shock and uneven loads, together with higher manufacturing accuracy, it is possible, firstly, to give the laying of window and doorways in gas-block walls from 150 mm (pos. 1 in the figure), while for foam blocks the laying of the same structural elements from 300 mm is required. 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 aerated concrete wall holds weight 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 puncher and a concrete drill, it’s enough hand drill without vibrator and conventional twist drill. Respectively, and there will be less garbage.
The most important performance characteristics structural cellular concrete, red brick and building timber summarized in Table. Some confusion may arise required thickness walls, but it is calculated, firstly, for a bare wall, without interior and exterior finishes, sheathing 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.
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 foam concrete house should be higher, and its shrinkage is less than for aerated concrete, i.e. and the foundation for foam concrete will cost more.
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 cross section 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.
Here we compare foamed concrete with wood. Taking into account the fact that wooden structures it doesn’t happen 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.
We will complete the review of the properties of aerated concrete with some additional parameters:
Expanded polystyrene concrete, or foam concrete, is not among the foamed concretes, but you need to linger on it. Foam concrete in recent times is heavily advertised, and there seems to be formal grounds 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.
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.
