Traditional technologies for building from reinforced concrete structures at this stage are experiencing a crisis associated with the successful development of alternative methods for constructing supporting structures. Masonry materials occupy a special place in this direction of installation, allowing the construction of low-cost facilities with high insulating qualities. The closest to the budget segment is the foam block production technology, which can be organized even in a household environment.
What is a foam block?
The product is part of a wide group of wall block materials, which are also formed by brick and stone materials. The fundamental structural difference of the foam block is the cellular structure. It is due to it that high levels of insulation and especially warming are achieved. Usually, among the weaknesses of this material is called a low level of strength, which is true if we compare with similar characteristics of the same brick. This is due to the fact that the density of the cellular structure, depending on the applied technology for the production of foam blocks, varies from 400 to 1200 kg / m 3 , while in row brick it reaches 3000 kg / m 3 .
Nevertheless, structural weakness does not prevent the use of a foam block as a structural building material, albeit with limitations. As already mentioned, its advantages are also due to economic factors. Firstly, this is due to the low cost of production - both in terms of raw materials supply, and in the technology of organizing the production process. As practice shows, the foam block production business with an annual output of about 10,000 thousand / m3 income is about 1-1.2 million rubles. Another thing is that this niche has its risks, therefore, a comprehensive analysis of demand and competitiveness at a particular site is initially required. Secondly, like most cellular concrete, the foam block is lightweight and resistant to external environmental factors, so you can expect to reduce costs in the implementation of logistics processes.
Necessary production raw materials for foam block
The mineral resource base for the manufacture of the foam block base may differ in the set of components, which depends on the requirements for the characteristics that must be provided for the building structure. But there is also a standardized recipe core, which is composed of ordinary cement, water and sand. This is a kind of filler that forms the material structure of the product. On this basis, modifications can be made by adding binders, plasticizers, frost-resistant additives, hardeners and other inclusions that improve the individual properties of the foam block. And on the contrary, if there are no strict requirements for technical and physical indicators, then the basic composition can be diluted with cheap raw materials like clay, ash, wood-chip production waste, etc. Reinforcing additions are also made, including fiber and fiberglass.
The main component that distinguishes the production technology of the foam block is a foaming agent. This can be a synthetic or organic component, due to which a cellular structure is formed. Again, in order to reduce the cost of the technology, inexpensive synthetic foaming agents are used, which reduce the strength and environmental cleanliness of the product. In addition, artificial components in some cases nullify the refractoriness of the structure. In turn, organic or protein foaming agents are made from natural material, which provides higher rates of insulation, fire resistance and structural resistance.
Equipment for the preparation of a mixture of foam concrete
The first stage in the production of the foam block is the one during which the solution is formed. At home, this part of the work can be implemented on conventional equipment for the preparation of cement mortar, but the quality of the product will be significantly lower. In the on-line production mode, it is desirable to organize the process of preparing the mixture on the following process units:
- Water tank. A special tank in which the accumulation and preparation of liquid for foam production is carried out. This construction differs from ordinary containers with a special coating of internal surfaces made of hard polyethylene, which protects the base of the tank and prevents damage to auxiliary equipment that will come into contact with the walls. In addition, in such tanks special equipment is provided for filling and draining technical fluid with a tap and valves.
- Foam generator. An obligatory functional component for the implementation of the foam block production technology, through which a homogeneous finely dispersed foam is formed with evenly distributed air bubbles. Specialized installations of this type make it possible to accurately control the foaming parameters in the average range from 150 to 400 g per 1 liter. This range just allows you to vary the density of the foam block from 300 to 1200 kg / m 3 . When choosing a foam generator, the water feed rate and pressure at the inlet to the pump unit are taken into account.
- Vibrosieve. An auxiliary device for screening sand and gravel aggregates of the desired fraction to increase the homogeneity of the solution. As applied to the foam block, the optimal fraction size of this component is 1.5-2 mm. The vibrosieve design itself is a metal mesh on a rigid frame, to which a vibrating apparatus with a power of 500-700 W is connected.
- Sand and cement dispenser. For small fraction fillers, weight dispensers are provided. Such installations are often used as part of the mini-production of the foam block to automate technological operations. The weighing accuracy of the dispenser can reach 0.5% with a working range of 10 to 1000 kg.
Molding technology
The prepared solution for the foam block is poured into a specially prepared form. This technology can be compared with traditional strip foundation methods for which formwork is being prepared. In this case, the formwork function is performed by a matrix form with cells corresponding to the dimensional parameters of the target block. In the conditions of factory production, a metal mold is used, provided with auxiliary devices for carrying and convenient distribution of the mixture over the honeycombs. A simplified technology for the production of foam blocks at home also allows the use of wooden structures. It can be made independently according to the principles of the crate, only with a bottom and a larger size - again, the parameters are determined individually depending on the characteristics of the final product. For this form, you can use the bars with planks fixed with ordinary hardware and reinforcing corners.
So, the prepared solution is distributed over the honeycombs, after which it hardens for 10 hours. That is, as part of the in-line production, one form can be used twice a day for shifts. After solidification, the structure is disassembled, and the blocks remain on the previously prepared bottom.
Cutting technology
An alternative way, in fact, of the same molding, but on a different principle. A niche is also being prepared for placing the solution, but this time without matrix cells. If we continue the analogy with the foundation, then in this case, a solid formwork is mounted under a monolithic casting or screed. You can use a prefabricated wooden structure, but with a capital reinforcement on the sides. The insulation material inside the mold is also thought through, since at high pressure the depressurization of the formwork with smudges is not ruled out, which will lead to the rejection of part of the blocks located at the edges. The array is kept for about 15 hours, after which the most crucial stage begins - cutting into individual blocks. This procedure is performed by a special circulation saw with a sufficient reach of the blade. In this case, it will be important not so much the high power of the equipment as the accuracy of the cut, to increase which the guides in the saw construction will help.
Both methods considered have their pros and cons, but which foam block production technology is better for private use? The cutting process is quite laborious and technologically complex, so the molding method is more preferable at home. But it is important to keep in mind that filling in honeycombs will not allow achieving the same quality of block geometry, as in the case with high-quality cutting.
The process of drying the foam block
The organization of the intermediate stage of polymerization has several important points. Drying to a large extent determines the quality of the natural pressing of the internal structure of the material. It is desirable that this process be intensive, since a high curing rate will prevent the risks, albeit insignificant, of deformation of the structure against the background of internal stress. As part of industrial equipment for the production of foam blocks, this function is performed by thermal drying chambers and furnaces, which within a couple of hours allow to achieve the desired state of the structure. At home, you’ll either have to stop at the option of natural drying, or use special heaters. Optimally for this operation, a heat gun is suitable, which gives a directed flow of hot air. The speed of the polymerization process will depend on the power of the apparatus and the selected thermal regime.
Mobile units for the production of foam blocks
Especially for small workshops and "garage" industries, industrial equipment developers offer optimized lines for the production of cellular block materials. The configurations of this equipment may vary, but in any design it is characterized by small size, autonomy and the ability to move. A typical machine for the production of foam blocks at home of this type is equipped with an installation with a foam generator and a capacity of up to 1000 liters. A special module is provided for cutting prepared foam concrete into blocks of specified parameters, which can be adjusted depending on current requirements. Despite the general optimization concept, such installations are provided with modern electronics with automated control, the presence of dispensers with level sensors and generators, providing the ability to work away from the central power supply lines.
Full-length foam block production line
Large enterprises use stationary lines with a full cycle of technological operations for the manufacture of foam block materials in large volumes. Such conveyors have an automated dispenser, containers for storing consumables with self-guiding hatches, as well as platforms for comprehensive machining of workpieces with high accuracy. Thus, a mini-plant for the production of foam blocks is organized within the framework of one workshop, the productivity of which can reach 150 m 3 of material per shift. Integrated line management can be carried out through the operator console or in automatic mode according to the specified programs separately for each functional unit through the industrial controller.
Foam block application
This material is widely used in various areas of construction. Frameworks of houses, lightweight foundation structures, partitions, as well as decorative objects in landscape design are built from it. Modern equipment for the production of foam blocks allows you to produce products of various shapes and sizes, which expands the possibilities for their structural application. For example, the process of reinforcing and creating complex grooves can be included in the process, thanks to which builders get more opportunities for installing block elements.
Conclusion
The distribution of foam concrete as such was caused by the growing demand for cheap housing with optimal technical and operational characteristics. Cost reduction in organizational work with finished blocks also contributed to the popularity of this technology. Using a small-sized machine for the production of foam blocks in the household, you can get ready-made building materials for building a house, bathhouse, technical structure or a separate structure with minimal costs. But it is important to consider the operational limitations of aerated concrete. The relatively low bearing capacity does not allow it to be used on seismically active soils, in the construction of multi-storey buildings, as well as to perform facial decoration from it.