Foam concrete is a very popular material for low-rise construction. In addition to industrial production, it is made independently. The release of blocks of various types can become a profitable business. However, the production of foam blocks at home has a number of features. Before you buy the right unit, you need to have an idea about the features of the material itself, the correct selection of related tools, as well as the consumption of the mixtures used.
Foam blocks are made of mortar, which includes:
- Portland cement;
- foaming agent (foam concentrate);
In this case, the bulk density of foam concrete can be different. In fact, it is concrete with a cellular structure. It is formed due to the mass of closed air bubbles. This feature causes a low density, as well as thermal conductivity of the material. At different density indicators, foam blocks can be used as heat-insulating, structural-heat-insulating and structural materials with low thermal conductivity.
As a rule, it is the brand of foam concrete that determines the level of its density. The lower it is, the smaller the amount of the mixture was used to make the material. This fact is reflected in the cost (foam concrete is cheaper than concrete). However, with a relatively low density, it is considered an advantageous material for the construction of partitions inside the house.
The foam block is easy to handle, tolerates cutting with a typical hacksaw. In addition, it does not collapse when nails are driven into it. In the work, it resembles wood, in shape it is a rectangle. Blocks can have different sizes: from standard elements to especially large ones.
Homemade foam concrete has the dimensions that are determined by the shape of the purchased unit.
Advantages and disadvantages
Foam concrete has many advantages, thanks to which it is in demand in the construction industry. This material practically does not change its quality and performance over time, it is not susceptible to aging. Environmental friendliness makes it harmless to the health of the manufacturer, builders and households. It does not emit toxic substances into the air, it is considered durable and reliable, it guarantees good thermal insulation.
In addition, it has high soundproofing properties, allows you to reduce the noise level, which is important for a modern person. The foam block is inert to fire. It is able to stabilize the temperature background inside the premises, is easy to install, and also has a high production profitability. Due to its light weight, it does not create an enormous load, like concrete. This allows you to reduce costs when installing the foundation.
However, along with the advantages, foam concrete has disadvantages. For example, despite the fact that it is considered durable, it loses to concrete and reinforced concrete. Other nuances include the fact that the foam block does not work on bending. It is unstable to moisture, as it is able to absorb it from the environment.
Regardless of whether material is produced at home or in production, it will shrink.
Equipment and tools
In the manufacture of foam blocks at home, you may need the following equipment and accessories:
- feed device for cement and sand;
- a foam generator with a capacity of at least 200 l / min;
- bar setup;
- dispenser of used water;
- vibrating screen (sifter of raw materials);
- hose for the exit of the finished mixture;
- concrete mixer with a volume of at least 250 l;
- special forms for blocks or a cutting machine.
Buying today the necessary equipment for the production of building materials at home will not be difficult. If desired, you can purchase not only a complete production line, but also its individual components. It is worth considering that the equipment for the production of foam blocks at home is not only stationary, but also portable. The line can be conveyor or automated. These factors determine the cost of equipment purchased.
At the heart of any set of equipment is a foam generator. Such a device per day can provide the release of about 100-110 cubic meters of material. A distinctive feature of stationary type lines is their high productivity along with excellent quality and low cost. Given that such a kit will cost about 1.5 million rubles, this calls into question its purchase.
Mobile foam concrete installation does not require the purchase of an expensive foam generator, which makes it popular in the construction market. However, along with this, it cannot boast of high performance. As a rule, in this case they use a barostation, but with all its power it is not able to produce more than 40-45 cubic meters of finished material per day.
In this case, often finished blocks are created with a high consumption of blowing agents.
Their strength is inferior to analogues created on stationary lines. The price of a complete set for home production can vary in the range from 50 to 300 thousand rubles. In this case, as a rule, equipment of high power has a high cost. For example, a kit for 300,000 rubles can produce about 72 cubic meters of foam concrete per day.
An automatic line needs large areas, which is often problematic, because this is not provided for initially. As a rule, such lines need to create bunkers for cement, water, sand, as well as additives with automatic dosing. In addition, you need to think about areas for drying foam concrete, pouring it in molds, as well as a saw cutter. This equipment is capable of delivering on average about 80-100 cubic meters of material per day, but not everyone can afford such a luxury, because a set will cost from 1.5 to 3 million rubles.
When at the initial stage there is not enough money, they buy used equipment. However, in this case, you should be prepared for the fact that it may be necessary to quickly replace any parts.
In addition, you need to understand that the equipment that was in operation, can cause poor quality of the finished foam concrete.
The forms purchased for foam concrete may be different. Today they are made of steel, plywood, as well as plastic. The capacity of the products is different, for example, you can purchase plastic molds with dimensions of 390x190x288 mm, options from plywood with a size of 588x300x188 mm, steel analogues with parameters of 600x300x200 mm. When buying them, it is important to consider the strictness of the geometry, since the quality of the finished material will directly depend on this. Even the slightest symmetry breaking is unacceptable.
When choosing molds for pouring foam concrete, it is worth paying attention to the material of their manufacture. Given that formwork can be combined, this is especially important. For example, if the seller notes that the metal version with inserts made of heavy-duty plastic is able to withstand even the highest temperature, do not blindly trust this.
The fact is that such forms are actually short-lived. In the process of drying and hardening of the foam concrete mass, a large amount of heat will be released.
Plastic, no matter how high-quality it is, reacts to a rise in temperature.
Consumption and proportions of the mixture
The proportions of the constituent ingredients in the manufacture of foam concrete are as follows: for 420 kg of cement (for example, grade M500) they take 420 kg of sand, 45 liters of water to produce foam and 120 liters of water for mortar. As for the foaming agent, its consumption depends on a particular brand. Usually for such a volume it is used in the range of 1.2-1.5 kg. Water for production can be taken not only tap water, suitable technical, moderate hardness.
The recipe and proportions directly depend on the density of foam concrete, which you need to get in the end. For example, if bulk density of foam blocks D 600 is needed, 210 kg of sand, 310 kg of cement, 110 l of water for mortar and 54 l for dilution of foam are taken. In addition, 1.3 kg of foam concentrate and 715 liters of foam are components of the building material. When mixing the entire number of components, a wet mass of 685 kg is obtained.
When a high density is needed (for example, 1000 kg per m3), the foam concrete mass is made of 590 kg of sand, 350 kg of cement, 120 l of water in solution, 42 l in foam. For this recipe, not more than 1 kg of foam concentrate and 560 liters of foam are used. As a result, in the latter case, the mass of raw materials for producing foam blocks is 1103 kg.
It is important to monitor the uniformity of the resulting foam and solution. This will increase the quality characteristics of the finished material. When choosing the right recipe, it is worth considering that according to the current GOST, the shrinkage of the finished material should not exceed 3 mm per 1 sq. m
How to make?
The production of foam blocks at home is carried out in two ways: casting and sawing. The classic do-it-yourself manufacturing technology involves the use of special forms of cassette type, having removable partitions and sides to divide the total capacity into separate sections of the same size. In such forms, the solution dries and hardens, after which the finished foam concrete is removed. The main advantage of this method of manufacturing building materials is the fact that the monolithic block does not need to be cut.
This eliminates the need to purchase a saw machine, which reduces equipment costs. However, it is the shape that can cause the violation of strict geometry. Not all molded elements after hardening will be perfectly smooth even when buying an expensive fixture. There will be a marriage in any case, and this is an extra expense for the mixture used.
In order to prevent the destruction of foam blocks, it is necessary to use a special lubricant that decomposes in the open air for several days.
Such substances are not cheap, however, if not used, this can cause chips or cracking foam blocks.
Most often, sawing technology is used in home production. In this case, one large mold is first poured, which is then subjected to cutting into individual elements of a given size. For this method, a sawing machine is bought. Although it will require certain financial investments, profitability will increase. The advantages of this method are the strict geometry of each element, as well as minimizing the formation of chips at the edges of the foam blocks.
However, this technique can hit the wallet well, as special equipment will be needed to produce small workpieces, but it is expensive. In addition, cutting a monolithic plate into small parts increases the time spent on the production of material.
The cutting machine comes in two varieties. In the first case, this is an aggregate on which a monolithic material is cut immediately after its hardening (molding). This is convenient because you do not need to transfer the entire plate to a sawing machine, thereby reducing labor costs and time. Cutting of foam blocks occurs due to special strings characterized by high precision cutting.
The disadvantages of these cutting elements are their fragility, as well as a decent cost.
The second type of cutting installation needs the transfer of foam concrete monolith for cutting. In this case, it is necessary to cut it with blade-type blades. Unlike strings, such knives are durable, and the units themselves are economical to maintain. However, to transfer foam concrete slabs to them, to put it mildly, is inconvenient and troublesome.
Hardening of foam blocks can be carried out in two ways: natural and autoclaved. At the same time, elements dried by the second method have the best quality characteristics. Thus, it is possible to create the most favorable conditions for obtaining good building material. However, the price of such equipment is significantly affordable, therefore, in the production of small volumes it is not bought.
Foam concrete, drying out on its own, dries better in the summer. As a rule, if the room temperature during drying is minus, you have to cover the formwork or consider creating special chambers for steaming foam blocks. In the first case, polyethylene or industrial batting is usually used. In the second, a room inside the production hall is allocated for these needs.
In such a room, a special temperature regime is created taking into account the necessary humidity for uniform and correct solidification of the blocks. Often, steam generators are used for these purposes, thus trying to automate the work process. When there is no extra money, but do not want to increase the drying time of foam blocks, resort to different budget options for solving this problem. Someone puts buckets of water in the chamber, in another case, they carry out communications with gas heating in it.
Those who are not satisfied with these decisions enclose a certain part of the production workshop with any available material that is notable for an acceptable price. For example, old bricks, profiled sheets or even the same foam blocks are used as a fence. When steaming the chamber with gas, the optimality of the selected mode must be taken into account. Ideally, the humidity in the room should not be less than 65%. However, if the production does not provide for the purchase of specialized equipment in the form of a humidity chamber, this may affect the certification of the finished material.
The standard technology for manufacturing foam concrete blocks at home consists of several operations.
- Initially, a foam concentrate is prepared in a separate container. Then it is combined with water and sent to a steam generator. If a self-production facility has a cavitation unit foaming contents by means of ultrasound, this step is skipped.
- At the next stage, it is necessary to make a mixture for foam concrete. For this, the necessary components of the mixture and special additives are placed in the chamber of the mixer. After that, the chamber is filled with previously prepared foam. According to the rules of technology, mixing in the chamber takes place within a few minutes.
- If a cavitation installation is used in production, initially a foaming agent is placed in the chamber for mixing . In this case, the remaining components of the working solution are placed later. At the same time, the stirring time should not exceed 0.5 minutes. At this point, the solution is ready to fill.
- After stirring, the composition is poured into existing forms. So that the mass does not stick to the surface of the equipment, the contact points are pre-lubricated with machine oil or special lubricating fluid. It is desirable that the room temperature during solidification and hardening of the composition is not less than +20 degrees ° C. After about 8-10 hours, foam concrete will gain one quarter of its strength.
This is the best time to cut it according to the required dimensions, as well as packaging. The final strength of the elements is gained after 28 days from the date of their manufacture. Vacation strength is considered to be one third of the set.
You can sell the goods in two days.
What to consider?
Sometimes it may seem that it is much easier to independently manufacture equipment for the production of foam blocks, using basic knowledge, power calculation and drawings, which today will not be difficult to find on the Internet. However, in fact, it is worth considering: the production of foam concrete in the conditions of a home mini-factory does not allow inaccuracies, since its benefit depends on it. You need to understand that in extreme cases, the factory product will not be difficult to sell in the future as unnecessary, while home-made products will remain unclaimed.
For the production of foam blocks, Portland cement of the M 500 brand is used. In order to improve the quality characteristics of the finished elements, various additives are added to it. For example, using the Bio NM modifier, it is possible to improve the resistance of foam blocks to frost. Due to the addition of Bio-Lux and Laston, it is possible to increase the air concentration in the structure of the material.
In order for the finished material to have excellent thermal insulation properties, an industrial type blowing agent must be purchased for its manufacture. No matter how much one wants to save money and make it on his own, he will not have heat conservation indicators similar to the version manufactured at the factory.
It is also important that high-quality raw materials are the basis of high-quality foam block.
You can find out the instructions for making foam blocks at home by watching the video below.