Production of foam concrete: an overview of the

17-08-2018

Building

Production of foam concrete as a business has recently become quite popular. The reason is quite simple: a relatively simple technology allows producing high-quality building materials, and the demand for material on the market contributes to increased profitability.

You can make foam concrete blocks even with relatively small financial investments

Preparation for production

Raw materials

So, if you decide to start producing foam concrete blocks on an industrial scale, then the first thing to take care of is the raw material. For the manufacture of high-quality material it is very important that all the components included in it meet the regulatory requirements, otherwise the operational quality of products will be highly questionable.

In preparing the mixture, from which we will make foam concrete building blocks, use the following components:

Water. Preferred is drinking, which does not contain impurities and other components. It is also allowed to use technical fluid and water from open reservoirs with a salinity of not more than 5000 mg / l.
Water for the preparation of the solution must comply with the requirements of GOST 23732-79: it should not contain oils, petroleum products, large mechanical particles, etc. The optimum stiffness is low or medium.

Note! To increase the effectiveness of the response, the liquid is heated to 45 - 55⁰WITH.

Portland cement M400 - M500. It is desirable to use formulations without mineral additives, with a stable structure and satisfactory quality indicators. Pozzolanic cements are rarely used in the manufacture of foam concrete.
The filler is sand with a particle size of not more than 1.5 and a minimum organic content. You should also choose species with a small amount of clay particles.
In addition to sand, you can use lime or dolomite flour, ash, blast furnace slag. In the process of preparation, all these materials are ground to a size of no more than 0.25 mm.

Also important components in the manufacture of construction foam block are a foaming agent (aluminum powder or organic composition of protein origin) and modifiers. The selection of modifying additives can significantly increase the rate of polymerization of the composition and improve the mechanical characteristics of the finished modules.

If we talk about the improvement of the mixture, then among the components used for this purpose it is worth mentioning the fiber. It is a steel or polymer fibers that strengthen the structure of cement, increasing the strength of the product as a whole.

Note! At 1 m³ no more than 1 kg of fiber must be added to the solution, so it does not have a strong effect on the mass of the material.

Equipment selection

An industrial scale plant for the production of foam concrete is usually completed with full-cycle plants, in which all operations are carried out sequentially and the movement of raw materials is carried out automatically. If we plan to organize the fabrication independently, then we can get by with a minimal set of equipment.

To do the work with their own hands will need:

Mixer - capacity in which the initial preparation of the mortar from cement and sand will take place.
Solution pump.
Penogenerator - a key component of the entire system, which injects foam into the solution. Typically, foam generators are made on industrial pumps of the vortex type.
Compressor - maintains pressure in the system. To ensure an optimal pressure of 8-10 bar, you need a receiver with a volume of at least 250 liters.
Water tankin which foaming is carried out.

In some cases, it is more profitable to purchase an integrated installation that combines all these devices. Of course, the price of such a unit will be somewhat higher, but its use significantly optimizes the production process and reduces labor costs. Good recommendations are used by domestic installations of BAS, Centaurus and their analogues with a cost from 50 to 100 thousand rubles.

The use of such systems allows the supply of foam concrete solution for pouring into the formwork directly on the object. If you are planning to make piece modules, then you will also need detachable cassette forms, as well as trays for drying products.

Technological cycle

Composition preparation

So, the equipment is ready, the raw material is purchased - you can get to work.

The production technology of foam allows several ways to obtain a solution with a high content of entrained air. You can compare these methods by analyzing the table below:

Production technique	Features of the process
Mixerная	We prepare the cement-sand mortar according to the classical technology, using a slightly smaller than necessary volume of water. In the foam generator by chemical reactions, foam is formed, which is fed under pressure into the mixer and introduced into the liquid solution. Most often, this technique is implemented using protein foaming components.
Dry	Cement is mixed with sand (ash, ground slag) in a dry form and thus goes into the mixer. Foam from the foam generator, obtained with the addition of a large volume of water, is also fed there. Typically, this technique is implemented in industrial production, since it pays off only for large volumes of products.
Pressure mixing	Preparation of the solution is carried out in a high-pressure chamber. First, it enters the water from the foam generator for foam concrete, and then dry components are poured. After the initial mixing, air is injected into the working chamber, which contributes to a more uniform distribution of air pores in the thickness of the material.

Note! Regardless of the technology used, the instruction recommends introducing modifying additives (modifiers, hardeners, pigments) into the solution only at the final stages of the reaction.

Getting the finished product

The prepared working solution under pressure enters the transport sleeve.

And here we can act in two ways:

First, the technology allows the pouring of foam concrete directly into the formwork. In this case, we lay the components in such a way that the material is enough to fill the required volume.
Secondly, the building blocks can be made from the solution. Here the process will be more laborious, therefore we will describe it separately.

The production of foam concrete modules is carried out as follows:

We assemble metal molds by fastening them with steel bolts. The wall thickness of the mold should be sufficient to prevent its deformation under the influence of the solution.
From the inside, we lubricate the mold with engine oil to avoid sticking of the finished blocks to the metal and cracking during extraction.
Next, we perform the pouring of the solution, distributing the material in such a way as to avoid the formation of large "air pockets".

Note! It is necessary to fill in forms at a temperature not below +15 - 18 ⁰C. Otherwise, the set of strength will slow down and by the time of extraction the blocks may fall apart.

After pouring, perform the primary drying. At this time, the mixture partially rises due to the residual reaction and gains strength.
About two hours later, we remove the blocks from the formwork and send it to the drying area.
The described technology is typical for the use of cassette forms. In the production of foam block by pouring a monolith, a large bar of material is cut into a band saw before drying in accordance with the design dimensions.

In principle, drying can take place under natural conditions. However, it is difficult to control the processes of cement hydration and solution strength gain. That is why it is recommended to use drying chambers for mass production.

The drying unit is maintained at a temperature of 40-55 ⁰WITH. Для полной полимеризации цемента блоки находятся в камере около 6 часов, после чего извлекаются из нее и после суточного «созревания» могут использоваться для строительства и утепления.

Conclusion

The organization of the production line for the production of foam concrete is possible only with the thorough knowledge of the technological process. However, the information presented in the text and in the video in this article is quite enough to get an idea of how this material is done. So after a little practice and consultation with specialists, you can easily organize such a business and successfully control it.