Vitaly Lviv One of them - are very effective in all respects and is well suited for all types of low-rise housing is aerated concrete. Foam concrete is superior to traditional sand-lime brick and ceramic stone on many parameters, so in this article we will discuss this relatively new material for the Russian market in more detail. Let's start with the basics. Concrete can be of several types: heavy, lightweight, easy, very easy, honeycomb. The main ingredients of which are producing concrete, they are: cement, water and sand. Concretes differ from each other fillers, and weight. And depending on the properties which acquired in the course of production - on purpose. Heavy concrete is on the foundations and vaults in the monolithic housing construction, lightweight and very easy - it is used for internal walls and partitions. In the building regulations clearly indicate the use of concrete of any kind. Designers use them when calculating the load on the building. Builders can only strictly follow the documentation. Meanwhile, in the arsenal of production firms and companies specializing in the suburban housing construction, a so-called aerated concrete that is used in all elements and nodes of the house - from foundation to roof. Aerated concrete (sometimes called cellular concrete) - a porous material has the properties of stone and wood together. Being, in essence, artificial stone, it has high strength, but due to the porosity of its thermal conductivity is almost as low as a tree. Foam concrete - it's easy to cellular concrete received as a result of curing solution consisting of cement, sand, water and foam .... Moreover, the foam can be created using conventional washing powder. The foam provides the required air content and its fairly uniform distribution by volume. After drying in concrete form closed cells filled with air. Foam concrete is made both in stationary conditions of production workshop and on site, where with the help of modern mobile technology and equipment can be obtained given the density of foam concrete. It is used in the form of blocks of different sizes or liquid. High-density foam concrete is used in the construction of the foundation or floor slabs. Less dense material used for the manufacture of precast blocks and panels partitions in buildings for insulation of floors and roofs, as well as to fill the voids and insulation. Many think that the aerated concrete - an achievement of modern scientific developments and technologies. However, this view is erroneous. This material has appeared in Russia for almost seventy years ago. In the 30 years of Soviet scientist, builder of an experimental Abdomen added to cement a soap-root - a plant that lived in Central Asia and forms the foam. As a result, the light of a new building material - foam concrete. Only later experts have begun to actively mix the cement with chemical additives - or foam-blowing agents (aluminum powder, kleekanifolnym solution, etc.). Based on these developments in Russia began to make building materials out of foam - blocks, partitions, wall panels, which by their thermal insulation properties exceed the brick and heavy concrete by 3-5 times. But despite the obvious advantages of the new material, foam in Russia is not stuck. There are several reasons: there was no quality foam, good units for the manufacture of foam and other equipment. Therefore, our builders continued to use the traditional "Russian" materials - brick and wooden beams. On the cellular lightweight concrete simply forgotten. But questions insulated building envelope that have been discussed recently at the federal level, "refreshed" memory builders. Once for an experiment laid out two walls - one of bricks, another of the foam. And it turned out, to keep the same heat in the room, the brick wall should be five times as thick aerated concrete. Thus, even a layman it is clear that the construction of a house made of brick, respectively, will take five times as much. That certainly makes the construction of brick rather expensive. To somehow solve this problem and little to reduce the thickness of the brick walls, the builders have done since time immemorial in masonry heat and sound insulation "layer" of mineral wool or polystyrene plates. But it does not save the situation: mineral wool quickly absorbs water, and polystyrene is flammable and toxic. Thus, a new page in the history of foam. In a better light its positive technical properties penobeton obliged internal cellular structure, reminiscent of aerated chocolate. And each air cavity, as the compartment of the submarine, hermetically separated from neighboring cells. As a result, water can not seep inside. At the expense of the same cellular foam concrete has good heat and sound insulator: in a house made of foam concrete warm in winter, cool in summer and at any time of year - quietly. Walls and partitions of the foam perfectly tolerate changes in temperature. They "breathe" and do not sweat. Microclimate in the buildings of foam is the same as in the wooden houses. Moreover, this material is environmentally friendly and fireproof: done-it with cement and sand, and, therefore, simply have nothing to burn. Foam concrete has the following properties: - High heat and noise protection qualities - high fire-resistant - durable - environmentally friendly - in line with European standards - economical (cubic meter of foam to 2 times cheaper than the volume of a brick) We now consider each property separately in the foam. Foam concrete - almost eternal material is not subject to time. One of its major properties - the closed porosity (air bubbles in it do not connect to capillaries), which allows to absorb the moisture is not more than ten percent. He is also an increased compressive strength and toughness, resulting from the foam is obtained a building material with low bulk density, but with good bearing capacity. Everyone knows that the best heat insulator is air. As already mentioned, foam at the 40-80 per cent consists of air bubbles due to the high thermal resistance of the building from his ability to accumulate heat, which during operation can reduce heating costs by 20 to 30 percent. To maintain a normal room temperature minimum wall thickness of the foam is 400 mm, while the thickness of the brick wall to achieve the same result should be not less than 700 mm. Foam concrete prevents significant heat loss in winter, is not afraid of moisture, protects from heat in summer. It regulates the humidity in the room by absorbing moisture and impact, thereby creating a favorable climate, comparable only to that of the microclimate of wooden houses. Low density, and hence the ease of foam concrete blocks, which are also larger in size brick, allow several times to increase the speed of masonry. In the easily treatable and finishing aerated concrete without much difficulty and high costs can be cut channels for wiring, sockets and pipes. When frame-Shield technology is going home as a child's constructor. Foam concrete has a relatively high capacity for sound absorption. In buildings of this material is provided with all applicable requirements for soundproofing. In the operation of aerated concrete does not emit toxic substances, and on its environmental quality is second only to the tree. For comparison: the environmental factor of the tree - 1 foam - 2 brick - 10 composite units - 20. Thanks to the good machinability of the material can bring to life the most daring design decisions to make curved walls, bay windows, arches, corners, niches, giving individual homes and architectural uniqueness. Cost of production and filling of liquid foam at the site does not exceed 700-800 rub. per cubic meter. Cubic meter of foam concrete blocks is from 1700 to 2300 rubles, a cube of wood - 3200-3500, bricks - 4500-5000 (plus the cost of binder solution, which for small bricks take longer than for the blocks). High geometric accuracy of high-quality units can put them on the glue or cement-sand mortar, to avoid "cold bridges" in the wall and significantly reduce the thickness of the exterior and interior plaster. Weight of the walls of the foam is much less than the weight of brick, so you can keep building on poor soils and save on a foundation, and accordingly, and the construction as a whole. In addition, there is no need to call a sling technique and team work. Products made of foam correspond to first-degree fire that is confirmed by the relevant tests. Material will not crack and is not destroyed with intense heat. Tests show that the foam concrete 150 mm thick protects the building from fire for four hours. The successful ratio of weight and volume can be used to transport any type of foam transport. Mobile plant for the production of liquid foam can be delivered to the usual "Gazelle". Foam concrete is well combined with any other material. The walls of the foam can impose a brick, to sheathe any type of lining, they stick tile, natural or artificial stone. Hygroscopic foam concrete grout the well, and in consequence has not produced delaminations and cracks. Houses of cellular concrete can even leave without finishing. It is calculated that they can stand in this form for 80 years. However, for aesthetic reasons they are still appropriate to cover the plaster, paint or oblitsevat brick. In the latter case it is recommended to leave an air gap between the veneer and the wall to ventilate the space between them. Shrinkage - that's a minus, however, should not be assumed that the foam concrete has only a chocolate-porous ins. Despite a number of positive characteristics, this material can be exposed and rightly criticized by experts. For non-autoclave foam as the material, the recently revived after long neglect, often imposed excessive demands and claims, and sometimes quite bizarre. In addition to complaints about frivolous buyers, there are quite objective shortcomings foam. The biggest issues is the so-called shrinkage, or rather shrinkage cracks. At the moment, has already subsided passion around this issue, there is no such fierce debate, but it does not mean that the issue was resolved with the shrinkage. Quite the contrary: the majority of foam manufacturers and builders simply put up with it, plasterers and sticking wallpaper, and under them cracks are not visible. But there are quite affordable ways to minimize shrinkage - just competently approach this problem. By the way, the shrinkage occurs in all materials containing cement in its composition, and consists of several components: contractional shrinkage, shrinkage and humid karbonizatsionnoy shrinkage. If the contraction shrinkage shut 100 grams of cement with water in a volumetric capacity, after its setting and hardening it becomes evident that the volume of hardened cement paste at 3-5 ml less than the volume of cement paste, from which this stone is received. Here, this phenomenon became known as contractional shrinkage. Deal with this shrinkage can only be reduced in the cement-sand composition of the cement itself, increasing the amount of filler, respectively, in the case of foamed concrete - this is only possible by increasing the amount of sand in the mixture (in the case of heavy concrete can increase the amount of the mixture not only of sand , and crushed stone). Naturally, replacing part of cement with sand, we will lose some portion of the strength of foam concrete and foam concrete with a focus prodelyvat quite dangerous, often the strength of foam is at the lower limit of strength for its density. Pay attention, because shrinkage of aerated concrete is subject only to cement, and such a way to combat it as increasing the number of aggregates in the mixture helps reduce all three types of shrinkage. Therefore, if there is an opportunity to apply foam concrete strength "smaller" should not be reinsured and the amount of cement to keep the project - it is better to turn down and get a lower strength foam concrete, but with less shrinkage. Karbonizatsionnaya This shrinkage shrinkage begins almost immediately after the manufacture of foam concrete and continues throughout the life of the foam products. Is it that being in the lime cement stone formed by the reaction of hydration reacts with carbon dioxide, which is part of the atmosphere to form calcium carbonate (aka chalk banal), with all its unpleasant consequences - the total amount of decrease, strength of concrete also decreases and the foam concrete "breaks." Visually, the samples of foam concrete, which is karbonizatsionnaya shrinkage, becoming pale yellow. Particularly intense karbonizatsionnaya shrinkage occurs in the insulating foam: the lower the density of the foam, the more carbon dioxide to reach deep into the material. At the same structural foam concrete density 700-900 kg / m cu. lain in the open air long enough to fracture the sample quite clearly visible boundary of the foam which was a reaction to foam concrete carbonation has not yet reacted with carbon dioxide. Deal with this shrinkage can only protect from the effects of aerated concrete air, when laying wall is required to plastering or hydrophobicity, for monolithic casting, for example, roofs, this device-quality steam and waterproofing monolithic foam concrete, etc. In addition to reducing shrinkage karbonizatsionnoy this method can reduce shrinkage and humid. Humid shrinkage is of great importance humid shrinkage. Cement, hardening, changes in volume. On air cement paste shrinks and the size of the product is shortened. If you take the long hardened foam concrete and put it in wet conditions, it will begin to increase in volume, lengthen, and this extension is called swelling. If, conversely, dried cellular concrete, it will start to shrink in volume and detect shrinkage. Long-term observations of cements, mortars and concrete confirm that the volume of all the products of cement depends on the humidity, and a change in storage conditions, there is a shrinkage (drying) or swelling (when wet). Foam concrete is particularly strong shrinkage for two reasons: its porosity contributes to the rapid penetration of air, and with it the moisture inside foam, and therefore it is moistened or dry much faster than ordinary concrete on gravel or crushed stone. In addition, sand, gravel and crushed stone do not experience shrinkage and prevent them grapple with cement to increase or decrease the volume of products and so reduce both shrinkage and swelling. If drying foam would occur uniformly over the entire thickness of it, and the shrinkage of the unit would be uniform, and damage from shrinkage would not be. But the drying up of the surface is faster than the inside, faster dry edges and corners, and this leads to the fact that the shrinkage is found more often in the corners, then at the edges of the surface plates and least of all in the middle. Outside of the foam will tend to cut, and the internal parts will prevent the reduction. This may lead to the fact that the outer part does not stand up and burst, appears at first very thin and shallow crack, and then with further drying, the crack will deepen and expand. The weaker material, the easier it cause cracks, so they will be more and more dangerous. Such a pattern often observed in practice. Therefore, upon standing in the foam forms, you should not give it to dry out too quickly, and this foam concrete is sprayed with water and even water is poured into the form on top of the block. After stripping units in stock, it is best to put on edge to drying on both sides went on the possibility of uniform. But it is necessary to create such conditions that the drying of the internal parts are not too behind to dry on the outside, it is necessary to delay drying of the surface, if we can not speed up the drying of the inner core. To do this, again, must be moistened with a foam concrete surfaces and keep it in a humid environment possible. Is too much watering retards shrinkage of both outside and inside, but the adverse effect on the strength has not. Uneven wetting one side when the other is not moisturized, harmful. The more foam concrete hardens, the easier it should be watering. The rate of drying depends on many factors: on whether there is a crust on the face or on the bottom bed plate as it is thin, large or small cells in the aerated concrete; on their thickness, how closely placed blocks, the air temperature, humidity him; on the type of cement and more from many causes.
Vitaly Lviv One of them - are very effective in all respects and is well suited for all types of low-rise housing is aerated concrete. Foam concrete is superior to traditional sand-lime brick and ceramic stone on many parameters, so in this article we will discuss this relatively new material for the Russian market in more detail. Let's start with the basics. Concrete can be of several types: heavy, lightweight, easy, very easy, honeycomb. The main ingredients of which are producing concrete, they are: cement, water and sand. Concretes differ from each other fillers, and weight. And depending on the properties which acquired in the course of production - on purpose. Heavy concrete is on the foundations and vaults in the monolithic housing construction, lightweight and very easy - it is used for internal walls and partitions. In the building regulations clearly indicate the use of concrete of any kind. Designers use them when calculating the load on the building. Builders can only strictly follow the documentation. Meanwhile, in the arsenal of production firms and companies specializing in the suburban housing construction, a so-called aerated concrete that is used in all elements and nodes of the house - from foundation to roof. Aerated concrete (sometimes called cellular concrete) - a porous material has the properties of stone and wood together. Being, in essence, artificial stone, it has high strength, but due to the porosity of its thermal conductivity is almost as low as a tree. Foam concrete - it's easy to cellular concrete received as a result of curing solution consisting of cement, sand, water and foam .... Moreover, the foam can be created using conventional washing powder. The foam provides the required air content and its fairly uniform distribution by volume. After drying in concrete form closed cells filled with air. Foam concrete is made both in stationary conditions of production workshop and on site, where with the help of modern mobile technology and equipment can be obtained given the density of foam concrete. It is used in the form of blocks of different sizes or liquid. High-density foam concrete is used in the construction of the foundation or floor slabs. Less dense material used for the manufacture of precast blocks and panels partitions in buildings for insulation of floors and roofs, as well as to fill the voids and insulation. Many think that the aerated concrete - an achievement of modern scientific developments and technologies. However, this view is erroneous. This material has appeared in Russia for almost seventy years ago. In the 30 years of Soviet scientist, builder of an experimental Abdomen added to cement a soap-root - a plant that lived in Central Asia and forms the foam. As a result, the light of a new building material - foam concrete. Only later experts have begun to actively mix the cement with chemical additives - or foam-blowing agents (aluminum powder, kleekanifolnym solution, etc.). Based on these developments in Russia began to make building materials out of foam - blocks, partitions, wall panels, which by their thermal insulation properties exceed the brick and heavy concrete by 3-5 times. But despite the obvious advantages of the new material, foam in Russia is not stuck. There are several reasons: there was no quality foam, good units for the manufacture of foam and other equipment. Therefore, our builders continued to use the traditional "Russian" materials - brick and wooden beams. On the cellular lightweight concrete simply forgotten. But questions insulated building envelope that have been discussed recently at the federal level, "refreshed" memory builders. Once for an experiment laid out two walls - one of bricks, another of the foam. And it turned out, to keep the same heat in the room, the brick wall should be five times as thick aerated concrete. Thus, even a layman it is clear that the construction of a house made of brick, respectively, will take five times as much. That certainly makes the construction of brick rather expensive. To somehow solve this problem and little to reduce the thickness of the brick walls, the builders have done since time immemorial in masonry heat and sound insulation "layer" of mineral wool or polystyrene plates. But it does not save the situation: mineral wool quickly absorbs water, and polystyrene is flammable and toxic. Thus, a new page in the history of foam. In a better light its positive technical properties penobeton obliged internal cellular structure, reminiscent of aerated chocolate. And each air cavity, as the compartment of the submarine, hermetically separated from neighboring cells. As a result, water can not seep inside. At the expense of the same cellular foam concrete has good heat and sound insulator: in a house made of foam concrete warm in winter, cool in summer and at any time of year - quietly. Walls and partitions of the foam perfectly tolerate changes in temperature. They "breathe" and do not sweat. Microclimate in the buildings of foam is the same as in the wooden houses. Moreover, this material is environmentally friendly and fireproof: done-it with cement and sand, and, therefore, simply have nothing to burn. Foam concrete has the following properties: - High heat and noise protection qualities - high fire-resistant - durable - environmentally friendly - in line with European standards - economical (cubic meter of foam to 2 times cheaper than the volume of a brick) We now consider each property separately in the foam. Foam concrete - almost eternal material is not subject to time. One of its major properties - the closed porosity (air bubbles in it do not connect to capillaries), which allows to absorb the moisture is not more than ten percent. He is also an increased compressive strength and toughness, resulting from the foam is obtained a building material with low bulk density, but with good bearing capacity. Everyone knows that the best heat insulator is air. As already mentioned, foam at the 40-80 per cent consists of air bubbles due to the high thermal resistance of the building from his ability to accumulate heat, which during operation can reduce heating costs by 20 to 30 percent. To maintain a normal room temperature minimum wall thickness of the foam is 400 mm, while the thickness of the brick wall to achieve the same result should be not less than 700 mm. Foam concrete prevents significant heat loss in winter, is not afraid of moisture, protects from heat in summer. It regulates the humidity in the room by absorbing moisture and impact, thereby creating a favorable climate, comparable only to that of the microclimate of wooden houses. Low density, and hence the ease of foam concrete blocks, which are also larger in size brick, allow several times to increase the speed of masonry. In the easily treatable and finishing aerated concrete without much difficulty and high costs can be cut channels for wiring, sockets and pipes. When frame-Shield technology is going home as a child's constructor. Foam concrete has a relatively high capacity for sound absorption. In buildings of this material is provided with all applicable requirements for soundproofing. In the operation of aerated concrete does not emit toxic substances, and on its environmental quality is second only to the tree. For comparison: the environmental factor of the tree - 1 foam - 2 brick - 10 composite units - 20. Thanks to the good machinability of the material can bring to life the most daring design decisions to make curved walls, bay windows, arches, corners, niches, giving individual homes and architectural uniqueness. Cost of production and filling of liquid foam at the site does not exceed 700-800 rub. per cubic meter. Cubic meter of foam concrete blocks is from 1700 to 2300 rubles, a cube of wood - 3200-3500, bricks - 4500-5000 (plus the cost of binder solution, which for small bricks take longer than for the blocks). High geometric accuracy of high-quality units can put them on the glue or cement-sand mortar, to avoid "cold bridges" in the wall and significantly reduce the thickness of the exterior and interior plaster. Weight of the walls of the foam is much less than the weight of brick, so you can keep building on poor soils and save on a foundation, and accordingly, and the construction as a whole. In addition, there is no need to call a sling technique and team work. Products made of foam correspond to first-degree fire that is confirmed by the relevant tests. Material will not crack and is not destroyed with intense heat. Tests show that the foam concrete 150 mm thick protects the building from fire for four hours. The successful ratio of weight and volume can be used to transport any type of foam transport. Mobile plant for the production of liquid foam can be delivered to the usual "Gazelle". Foam concrete is well combined with any other material. The walls of the foam can impose a brick, to sheathe any type of lining, they stick tile, natural or artificial stone. Hygroscopic foam concrete grout the well, and in consequence has not produced delaminations and cracks. Houses of cellular concrete can even leave without finishing. It is calculated that they can stand in this form for 80 years. However, for aesthetic reasons they are still appropriate to cover the plaster, paint or oblitsevat brick. In the latter case it is recommended to leave an air gap between the veneer and the wall to ventilate the space between them. Shrinkage - that's a minus, however, should not be assumed that the foam concrete has only a chocolate-porous ins. Despite a number of positive characteristics, this material can be exposed and rightly criticized by experts. For non-autoclave foam as the material, the recently revived after long neglect, often imposed excessive demands and claims, and sometimes quite bizarre. In addition to complaints about frivolous buyers, there are quite objective shortcomings foam. The biggest issues is the so-called shrinkage, or rather shrinkage cracks. At the moment, has already subsided passion around this issue, there is no such fierce debate, but it does not mean that the issue was resolved with the shrinkage. Quite the contrary: the majority of foam manufacturers and builders simply put up with it, plasterers and sticking wallpaper, and under them cracks are not visible. But there are quite affordable ways to minimize shrinkage - just competently approach this problem. By the way, the shrinkage occurs in all materials containing cement in its composition, and consists of several components: contractional shrinkage, shrinkage and humid karbonizatsionnoy shrinkage. If the contraction shrinkage shut 100 grams of cement with water in a volumetric capacity, after its setting and hardening it becomes evident that the volume of hardened cement paste at 3-5 ml less than the volume of cement paste, from which this stone is received. Here, this phenomenon became known as contractional shrinkage. Deal with this shrinkage can only be reduced in the cement-sand composition of the cement itself, increasing the amount of filler, respectively, in the case of foamed concrete - this is only possible by increasing the amount of sand in the mixture (in the case of heavy concrete can increase the amount of the mixture not only of sand , and crushed stone). Naturally, replacing part of cement with sand, we will lose some portion of the strength of foam concrete and foam concrete with a focus prodelyvat quite dangerous, often the strength of foam is at the lower limit of strength for its density. Pay attention, because shrinkage of aerated concrete is subject only to cement, and such a way to combat it as increasing the number of aggregates in the mixture helps reduce all three types of shrinkage. Therefore, if there is an opportunity to apply foam concrete strength "smaller" should not be reinsured and the amount of cement to keep the project - it is better to turn down and get a lower strength foam concrete, but with less shrinkage. Karbonizatsionnaya This shrinkage shrinkage begins almost immediately after the manufacture of foam concrete and continues throughout the life of the foam products. Is it that being in the lime cement stone formed by the reaction of hydration reacts with carbon dioxide, which is part of the atmosphere to form calcium carbonate (aka chalk banal), with all its unpleasant consequences - the total amount of decrease, strength of concrete also decreases and the foam concrete "breaks." Visually, the samples of foam concrete, which is karbonizatsionnaya shrinkage, becoming pale yellow. Particularly intense karbonizatsionnaya shrinkage occurs in the insulating foam: the lower the density of the foam, the more carbon dioxide to reach deep into the material. At the same structural foam concrete density 700-900 kg / m cu. lain in the open air long enough to fracture the sample quite clearly visible boundary of the foam which was a reaction to foam concrete carbonation has not yet reacted with carbon dioxide. Deal with this shrinkage can only protect from the effects of aerated concrete air, when laying wall is required to plastering or hydrophobicity, for monolithic casting, for example, roofs, this device-quality steam and waterproofing monolithic foam concrete, etc. In addition to reducing shrinkage karbonizatsionnoy this method can reduce shrinkage and humid. Humid shrinkage is of great importance humid shrinkage. Cement, hardening, changes in volume. On air cement paste shrinks and the size of the product is shortened. If you take the long hardened foam concrete and put it in wet conditions, it will begin to increase in volume, lengthen, and this extension is called swelling. If, conversely, dried cellular concrete, it will start to shrink in volume and detect shrinkage. Long-term observations of cements, mortars and concrete confirm that the volume of all the products of cement depends on the humidity, and a change in storage conditions, there is a shrinkage (drying) or swelling (when wet). Foam concrete is particularly strong shrinkage for two reasons: its porosity contributes to the rapid penetration of air, and with it the moisture inside foam, and therefore it is moistened or dry much faster than ordinary concrete on gravel or crushed stone. In addition, sand, gravel and crushed stone do not experience shrinkage and prevent them grapple with cement to increase or decrease the volume of products and so reduce both shrinkage and swelling. If drying foam would occur uniformly over the entire thickness of it, and the shrinkage of the unit would be uniform, and damage from shrinkage would not be. But the drying up of the surface is faster than the inside, faster dry edges and corners, and this leads to the fact that the shrinkage is found more often in the corners, then at the edges of the surface plates and least of all in the middle. Outside of the foam will tend to cut, and the internal parts will prevent the reduction. This may lead to the fact that the outer part does not stand up and burst, appears at first very thin and shallow crack, and then with further drying, the crack will deepen and expand. The weaker material, the easier it cause cracks, so they will be more and more dangerous. Such a pattern often observed in practice. Therefore, upon standing in the foam forms, you should not give it to dry out too quickly, and this foam concrete is sprayed with water and even water is poured into the form on top of the block. After stripping units in stock, it is best to put on edge to drying on both sides went on the possibility of uniform. But it is necessary to create such conditions that the drying of the internal parts are not too behind to dry on the outside, it is necessary to delay drying of the surface, if we can not speed up the drying of the inner core. To do this, again, must be moistened with a foam concrete surfaces and keep it in a humid environment possible. Is too much watering retards shrinkage of both outside and inside, but the adverse effect on the strength has not. Uneven wetting one side when the other is not moisturized, harmful. The more foam concrete hardens, the easier it should be watering. The rate of drying depends on many factors: on whether there is a crust on the face or on the bottom bed plate as it is thin, large or small cells in the aerated concrete; on their thickness, how closely placed blocks, the air temperature, humidity him; on the type of cement and more from many causes. Just a lot of reasons, in advance to schedule a term exposure and the degree of hydration can not, and should, in each case to decide the circumstances, firmly in mind that the problem of aging - to give mature foam as possible favorable conditions. Sometimes, it would seem, properly restrained foam concrete is still covered with cracks. It turns out that in this case, plates with cracks fall into the conditions of uneven drying. Or plate provided at the door in the draft, or driving traffic to the sun, or anything else like that. This happens because the wind and the sun always accelerate drying, and the unit quickly dried up from the surface, while the inner layers of its dried up slowly, the shrinkage was so great on the surface that produces a tear and cracks. Limits foam water absorption foam a little from behind a closed cell structure. Since many of the properties of the gas light concrete depend on the success of the process of curing, below are some of the methods by which the strength can be increased. On compressive strength of foam concrete is influenced by many factors, such as weight, age, moisture content, physical and chemical properties of mixture components and their proportions. Consequently, it is desirable composition of the mixture, the type of cement and sand or other filler to keep constant. Between density and strength of relationship exists. Any change in these factors could change this ratio is very noticeable. Compressive strength can be increased by using special methods of storage. Wet conditioning has a major impact on the increase in compressive strength. For foam concrete blocks they be wrapping a special material to retain moisture. They can also steam thoroughly. Foam concrete has a linear increase in compressive strength in 12 months, in contrast to the heavy concrete strength which is aligned much earlier. Compressive strength continues to increase in future due to reaction with CO2, present in ambient air. A significant difference also lies in the fact that the aerated concrete has a higher rate of curing, than the heavy concrete. If the compressive strength must be high accelerating aging can be achieved through the use of CO2. In particular, it can be used in factories producing panels and components. Depending on the method of curing, tensile strength of aerated concrete can be 0.25 part of the compressive strength of the longitudinal strain of about 0.1%. In general, the shear strength varies by 6% - 10% of compressive strength. Shear stress are rarely in the roof and ceilings, floors. Foam concrete, like all cement materials is the phenomenon of shrinkage during installation. The degree of shrinkage depends on various factors such as type of cement, the method of storage, size and quality of sand, the amount of cement in the mixture, the density of concrete and water-cement ratio. The main shrinkage occurs during the first 28 days, after which it is insignificant. During the first 28 days if the production of concrete observed shrinkage is usually less than 0.1%. Very often, the appearance of cracks in the walls caused by the movement of the base attributed to shrinkage. If the crack was formed 28 days after placement of concrete, it is not due to shrinkage. Linear expansion coefficient for foam has the same meaning as for normal concrete, that is 0.000009 per degree centigrade. This factor is important when using concrete in large areas of roofs that are exposed to heat and cold. Foam concrete has a high sound absorption values. In general, the heavy concrete tends to deflect the sound, while the cellular concrete absorbs sound. Sound transmission, however, conventional walls can be higher by 2-3% compared to heavy concrete. This is due to the fact that most of the walls are plastered and / or painted, that rejects sound, as in the case of heavy concrete. On the other side of foamed concrete are well absorbed by the low frequency noise. Therefore, it is often used as a soundproofing layer on structural concrete slabs in order to limit noise transmission floors in high-rise residential or office buildings. How to build from foam Foam is suitable for all types of construction: both the public and private. And wish to have your own house can do little blood and in a financial sense, and sense of time. Need only have the appropriate equipment. Here we must add the important thing: this equipment is not cheap - about ten thousand dollars. Most likely, this price is a summer resident discourage any desire to build a house out of foam. But do not despair: a way out of this situation is - you need to find a company that has a system for making aerated concrete. Its staff will arrive on site, bring equipment and start building a house. If you still want to acquire their own equipment, then your return will "chip in" with neighbors and get set up a purse. In general, no special assembly foam concrete does not prepare, and therefore did not build. It's time to do calculations to determine how much cost us the house of the foam. We proceed from the fact that building a wall for the home, for example, the size of 6x6 m. The first thing to decide on the architectural design. Suppose you have chosen your project. What's next? As you know, building a house begins with the foundation. After working to make a foundation and it hardens, you can begin construction. To do this, buy "raw material" (cement and sand), to pump water from the well and to invite a team working with aerated concrete plant. Build a house it is quite possible in parts: first, the wall, then walls, then roof. Incidentally, in the foam concrete can drive nails, it is very easy to paint and even cut an ordinary hacksaw. So that the wall can be reduced by simply cutting off. If you decide to use a monolithic styling with a concrete panel or decides to lay down a house of prefabricated aerated concrete blocks, construction costs will increase significantly. So before making a decision, it is necessary to weigh all the pros and cons. Recipe for foam production technology of foam concrete is rather simple and something even like cooking a cake. First knead "dough" made of cement, sand and water (and in some cases instead of sand added to polystyrene pellets - if the material is obtained more easily). Then, in a homogeneous mass is added finished foam, which makes foam concrete porous. "Dough" is ready, you can create building blocks, slabs, walling. In modern conditions the foam made of foam concentrate. It is produced by commercial methods. To prepare the foam requires special equipment, such as foam generator, or plasma system, which not only "whips" foam, but also mixing with cement mortar. Adding to install a hose can be fed (transport), ready-mixed to the house being built to a height of 20 m and a distance of 40 m. handles the installation of two people, but the performance is amazing - 1600-4000 liters per hour! The only condition: in order to obtain high-quality foam concrete, the air temperature during mixing should not be below 10 C. Setting a fairly compact: takes about 2.5 meters, it easily can be put in the back "Gazelle" and drop off the construction site. By the way, it can help to make cellular concrete, not only on the street, waiting for the cherished +10 ° C, but also in the room (if you need to fill in, say, sex or make a partition). In the manufacture of units using monolithic stacking, in which the foam concrete is poured into the formwork, thus obtaining a wall, partition, etc. Decking is a removable (sliding) and non-removable. For removable formwork used fibreboard. They put on two sides, poured into the foam concrete and then removed. It turns smooth wall or partition. Where DWT is used repeatedly. When permanent formwork possible different options: either both sides erect a wall of brick and aerated concrete is poured between them, either from the outside - a brick and the inside - fiberboard, gypsum board, etc. Once between the two layers of foam concrete floods drown, fiberboard can be removed, but you can not shoot - it's a matter of taste. If you do decide to remove the hardboard and leave within a "foam" surface, it can be painted, glued to her tiles, etc. If you want to make a monolithic stacking, takes care of the mold a firm that is building. But we should not forget that the monolithic installation of permanent form (especially if both sides are built of brick wall) construction of price increases several times. In other words, a monolithic styling with removable formwork is cheaper than with non-removable. Do not want to communicate with the monolithic styling? Fold the house of prefabricated foam blocks that hold them together with cement mortar. Blocks are sold in specialty stores and construction markets. You can apply directly to producers of products made of reinforced concrete - concrete products plants. Dimensions of the foam blocks are different, but usually it's the "brick" of 0,2 x0, 2x0, 4 m (width x height x length) or 0,2 x0, 3h0, 6 pm And another thing: if you build a house, pre-engineered , it still would cost less than brick. And yet, on what to choose - the construction of the aerated concrete blocks and construction of frame-and-panel house with all of the same foam, but not in the solid and in liquid form? If you have decided to put the blocks is easily and quickly erect a wall. On the floor will be used reinforced concrete slab, which is beneficial in terms of cost and time savings. In addition, the result is a geometrically smooth surface, allowing to conduct any work. Well, if you want to live in a hollow-frame-house built on new technology, you also will not have to endure all sorts of inconveniences. Initially manufactured home frame of wood or light walled steel structures. Then the wall panels are faced with a skeleton outside any traditional materials - brick, after which the phased lining. Between the outer and inner layers is filled with foam concrete, which is two times lighter than the blocks. Due to the strong properties of the bulk and design of the metal frame, even in earthquake-prone areas can build three four-story house with a decrease in wall thickness and reducing consumption of materials. Very convenient that the blocks can be sawn, drilled, milled. According to its characteristics and consumer properties of the material closest to the tree, but has a much greater longevity. Foam concrete is very technologically during installation. Blocks of foam are quite large, with a small mass. For example, the block size 500h300h200 weighs from 18 to 28 kg depending on the density, thereby reducing labor costs. A team of 3 people can cope with the assembly house of the foam blocks, an area of ??120 m3, only 10-12 working days.
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