With the development of technology and science, mankind is developing new materials for the construction of structures for various purposes. Some of the newly converted are foam concrete and aerated concrete. In this article we will focus on foam concrete.
Products from foam concrete are a fairly young generation of environmentally friendly building materials, advancing “on the heels” of the older generation.
Now, since the 90s, the production and use of foam concrete has grown significantly in volume and is experiencing a real boom.
Reference: Foam concrete. lightweight cellular concrete obtained by hardening a solution consisting of cement, sand, water and foam. Foam provides the necessary content and even distribution of air in concrete. Foam is obtained from a foam concentrate (foaming agent). Various organic and inorganic compounds can be used as a foaming agent: obtained on the basis of natural protein, and synthetic compounds obtained in the production of detergents. Foam concrete is inexpensive, economical, durable, environmentally friendly, biologically resistant material, more environmentally friendly than wood, but non-combustible and durable.
The material itself was invented and patented relatively recently. in 1924 by the Swedish architect A. Erickson. By historical standards, this is a short time.
Products from foam concrete are made in the form of blocks, monoliths, using cutting or filling technologies, by autoclave and non-autoclave methods. In fact, this material can be given any shape.
To correctly calculate the characteristics of the material, use the table No. 1 given here:
The use of foam concrete in the form of blocks or a monolith during the construction of buildings allowed to obtain properties that are unattainable when using other materials:
- Firstly, foam concrete is absolutely environmentally friendly, due to the porous structure it can conditionally be attributed to “breathing” materials, which contributes to the formation of a natural microclimate in the building (room).
- Secondly, it is heat (frost resistance) and sound insulation, the last of which is somewhere around 60 dB. If everything is clear with sound insulation, then there is something to add about thermal insulation. Thermal insulation in houses is adjustable, due to the same porosity of foam concrete. Mold, fungus or fogging of glass in foam concrete houses is an extremely rare occurrence. The air in the pores of the material serves as an additional pillow, prevents the loss of heat or, conversely, coolness, preventing the balancing of internal and external temperatures.
- Thirdly, it is durability and fire safety due to the fire resistance of the material. Everything is clear with fire resistance. it is achieved by the fact that the foam blocks do not contain combustible materials, and therefore they do not burn, do not melt, do not crack, and even at high temperature they hold their shape, do not lose strength and do not collapse. The durability of foam concrete is identical to ordinary concrete, which also only grows in strength over time. The durability of the material is associated with high weather resistance and is explained by low moisture absorption by the material.
- Fourthly, it is ergonomics and profitability. Products made of foam concrete, subject to the requirements of state standards (GOST 12.1.007–76, GOST 25485–89 “Cellular concretes. Technical conditions”), in terms of exposure to harmful substances (toxicological characteristics), belong to the non-hazardous category. low-hazard substances. In fact, this is a degree close to absolute environmental friendliness, which cannot be improved even if the porous surface of the blocks is filled with the clean air of alpine meadows. Ergonomics and efficiency are determined by the low cost of the material or products made of it, size, weight. So, with average block sizes (60cm x 30cm x 20cm), almost thirteen times the size of a regular brick (25cm x 12cm x 8.8 cm), its weight is only slightly more than 23 kg. When the ratio of the volume of foam concrete to brick or wood (1 m³) is 1/1, foam concrete is cheaper than wood by an average of 30%, and brick by 40. Reducing weight with an increased volume and acceptable strength reduces the weight of the entire building, reduces the pressure on the foundation.
- And finally, fifthly, this is the ease of processing. This material is perfectly sawn, processed, and at the same time practically does not prick. No special or expensive equipment is required for processing. An ordinary hacksaw is fine.
The main scope of the use of foam concrete products is construction. In this case, we are talking about construction in any climatic zones at any humidity. Foam concrete is used as a building and heat-insulating material and is divided into heat-insulating, structural and structural-heat-insulating blocks. Its density directly affects the weight, strength of the product and the entire structure.
Table 2 provides information on the use of foam concrete, depending on the brand:
If your purchase of building material requires your salary for the year, which you do not have, then something needs to be done. There are several solutions, from the job as a watchman to the epic phrase “And it went. "
But we will not rush to the extremes and stop, or rather, we will offer a completely acceptable solution. to make foam concrete ourselves, in the quantities necessary for personal needs. Unfortunately, we will not be able to produce foam concrete for free. Even our craftsmen have not yet invented it. Perhaps, over time, people will learn how to compress air to the required density or solidify water, but when this happens, we will pay no less for air and even more for water than now for foam concrete. Therefore, we will not lose time and proceed to solve our common problem.
For the production of foam concrete of the most common brand D600, we need: cement, sand, water, foaming agent, equipment and formwork. We will dwell on the equipment in more detail. So, we need to make: a mold for foam blocks, a mixer, a foaming agent.
The form for foam blocks is made, as a rule, of standard sizes identical to the factory ones (60cm x 30cm x 20cm) from durable materials, for example, metal sheets. Naturally, the mold can be made of any size and from less durable materials, but in this case it will not last long.
The form is a welded metal rectangular box, divided into identical cells, which are blocks. All welds and fasteners should be located exclusively on the outside, so that the inner surface of the blocks remains smooth, and the foam blocks inside them are easily removable.
In order not to reinvent the wheel, a concrete mixer can be used as a mixer, which is quite common in households. In addition, a concrete mixer will be very useful for preparing the mortar when laying foam blocks. Another, far worse alternative to a mixer is to use an electric drill equipped with a mixing nozzle. In this case, a vat, a large pan-boiling pan, an old bath, etc. can be used as a container for kneading.
The volume of the concrete mixer or the capacity replacing it must correspond to the volume of one and several forms for foam blocks, so that one batch is enough for a whole batch of blocks placed in the form. Otherwise, it will take two or more batches to fill the mold, which will negatively affect the technology for manufacturing foam concrete, especially at the drying stage, which occurs immediately after filling the blocks of the foam concrete mixture.
The next in our list of equipment for the production of foam concrete and the most difficult to manufacture is a foaming agent.
Made on its own, the foaming agent is a system of inlet and outlet valves and a compressor unit mounted on a large sealed container (you can use a metal barrel for this purpose). The outlet valve must be equipped, in addition to the valve, with a fine grid. Water and a blowing agent are loaded into the tank. The compressor and valve system adjust the density of the substance, the pressure inside the tank, and the supply of finished foam is organized. The fine-mesh grill promotes even distribution, mixing and formation of foamed material or simply foam. It is necessary to approach the design and manufacture of the foaming agent with all responsibility, after familiarizing yourself with the schemes and drawings of other working models, since the quality of the foam blocks and the monolith depends on the quality of the foam.
Video: How to Cut Foam Blocks at Home
To obtain a monolithic foam concrete, formwork is necessary. It does not make sense to make the formwork yourself and this is the case when it is enough to limit ourselves to using ordinary factory products used in construction.
Below, in the presented video, a visual description of the working foaming agent is given. Technical solutions used in its manufacture can be applied to the development of other prototypes.
Video: homemade foam concrete plant
The production of foam blocks is conditionally divided into two parts (pouring individual blocks and creating monolithic foam block walls), and two stages (preparatory and main stages). Therefore, we will consider production technology separately.
Before the main stage of manufacturing foam concrete, it is necessary to organize a workplace. Take care of the supply of water and electricity, the availability of the necessary tools, tanks, equipment, materials. Determine the optimal number of assistants, the sequence of actions performed, as well as the responsibilities of each. Prepare components used for production.
To comply with the exact ratio of the components of foam concrete, it is not out of place to use a table with the proportions, which must be compiled or printed from the Internet and be within reach. Naturally, it will not work to foresee everything, especially if you start manufacturing foam blocks for the first time. Indeed, such factors as the temperature of the environment, water used, air humidity, the types of foaming agents used and the quality of the foam, which depends on the foaming equipment, the operation of other equipment involved, the uniformity of the foam concrete and others, will directly affect the quality of work and the final result.
Table 3 shows the proportions of various grades of foam concrete:
Block Fill Technology
First you need to prepare molds for filling foam concrete. The molds are mounted on a flat and hard surface. Inside lubricated with machine oil, for easy extraction of blocks. In the process of installing the molds, it is necessary to take care of protection from atmospheric precipitation and, if they exist, to protect the surface of the blocks from getting wet.
You can also purchase ready-made foam balls and just add them to the cement mortar in the proportion specified by the manufacturer.
We fill in the forms with a ready-mixed aerated concrete solution (preferably within 20-30 minutes) to exclude quality losses of the initial foam concrete mixture. After filling out the forms, leave them to dry for up to 48 hours, depending on weather and climatic conditions. Finished foam blocks are removed from the molds and are ready for use during construction work.
Photo gallery: a form of molds for the manufacture of foam concrete blocks
Creating monolithic foam block walls
To create monolithic aerated concrete walls, instead of forms, reusable removable formwork is used. This design allows you to create a wall without seams and additional plastering. But the volumes of the prepared solution increase several times. It can be purchased both factory-made and do-it-yourself.
It is necessary to take moisture-resistant sheet material, multilayer plywood or OSB is best suited. With the help of plywood sheets (you can also take pine slats) the formwork and the thickness of the future wall are formed. Inside the wall, in the place where the foam concrete will be poured, a metal frame is formed from a metal profile or reinforcement in order to give strength to the future wall. Metal can not be welded using electric welding, but it will be enough to tie the ends of the reinforcement with wire. From above, the formwork must be fastened with transverse beams or brackets so that it does not tear apart as the formwork is filled with foam concrete.
After the formation of the formwork, we proceed to fill it with foam concrete, according to the production technology of aerated concrete blocks.
Photo Gallery: Production of monolithic foam concrete
Do not forget that to fill the formwork will require significant amounts of foam concrete. Usually it is served by a special pump, which ensures an almost uninterrupted flow of the mixture into the formwork. In the absence of such a pump, more people will be required for uninterrupted production and supply of aerated concrete mixture to the formwork until it is completely filled. This is necessary for uniform pouring and wall formation, and, most importantly, for preserving the initial properties of the foam concrete mixture. In the absence of foaming substances, foam balls can be purchased and added to the solution.
Due to its unique properties, monolithic foam concrete is held on more firmly in construction and deserves high respect. Its properties provide thermal insulation of rooms and facilitate the mass of structures, which together leads to a wide demand for aerated concrete products in the consumer market. And to make blocks with your own hands or to build a wall from monolithic foam concrete does not present any special difficulties. there would be a desire.
DIY foam concrete production video
Foam concrete blocks are used in the construction of low-rise buildings. This is due to their good sound insulation, environmental friendliness, ease of transportation, handling and other operational characteristics. Many masters care about how to make a foam block.
The choice of equipment for work
Experts note that the profitability of manufacturing modules from aerated concrete exceeds 300%. The master does not have to carry a large investment, the finished material can be used for your own needs or for sale.
Home fishing line for the production of foam blocks will require the installation of these units:
- compressor. the technical characteristics of the equipment should allow it to function from a standard 220 V power supply network;
- foam generator. can be purchased from companies specializing in the production of foam blocks or made independently;
- forms. the product can be metal (sheet metal 3-4 mm) or plywood (moisture resistant material enclosed in a metal frame). It is better to use collapsible structures, with folding sides and removable longitudinal and transverse partitions. The size of the mold should be small. it is convenient for transportation;
- pump. the choice of device is based on the required performance;
- concrete mixer. the optimal volume of 80-100 liters.
Multilevel forms adversely affect the quality of the mixture. it will harden poorly
With this equipment a team of two workers can produce 2-3 m³ of concrete per shift. The main difficulty is the production of foam. Foaming agents produce much less foam than a high-quality foam generator, and the solution should practically be whisked at very high speeds.
How to make a foam generator for foam concrete with your own hands?
Before you make a foam generator for foam concrete yourself, you need to understand the principle of its action:
- the foam concentrate solution is supplied at an angle of 90 ° into the mixing chamber;
- the composition is connected with the flow of air;
- the mixture, under pressure, passes through a double-cut nozzle;
- at the input, the composition is compressed; at the output, it expands. The mixture escaping under pressure is transmitted to the cartridge, where it breaks into foam.
The master can himself get high-quality foam, spending a minimum of money on the manufacture of the device. The design implements the principle of pair valves. Shut-off valves are used to shut off the system, adjusting. set the density of the foam. Having selected the optimal parameters only once, subsequently you can use only shut-off valves.
To assemble a foam generator with a Laval nozzle, all parts should be connected in series:
- solution shut-off valve; coupling;
- mixture control valve and foam density adjustment coupling;
- air shutoff valve coupling;
- air supply control valve (allows you to adjust the pressure) coupling;
- a chamber for mixing foam concentrate and air;
- Laval nozzle, d 10 mm. Instead of a nozzle, a jet washer can be used, but the efficiency of the unit will decrease by 40%;
- foam cartridge;
- threaded nozzle with mesh washer.
To operate the device a compressor is needed, the productivity of which is 0.50 m³, pressure. about 6 Atm. Foam concentrate, diluted in a separate container (100-200 l), can be served through a simple household pump, such as a trickle.
The cartridge case along the entire length is filled with rolled up grids, for which you can use stainless steel grids for cleaning dishes
For a large amount of work, a pump equipped with a receiver is required. If the device provides a pressure of about 2 atm, the unit will give out 300-500 l / min, 6 atm. from 600 l / min and more.
To make foam yourself at home, you will need these components:
- cement. high-quality material without impurities is selected, grade strength not lower than M400;
- sand. starting from a density of 600 kg / m³, natural or crushed sand is added, but screening can be a better choice, since it is cheaper and more active in concrete. If large grains of sand are mixed in the dough, cement will have to be added to it, which will allow to keep the foamed solution. For thermal insulation modules. 300-500 kg / m³. this component is not used. It is recommended to sift the sand several times;
- foaming agent;
Foam concrete: composition, proportions
Before you make foam blocks at home, you should familiarize yourself with the proportions for its manufacture.
To prepare 1 m³ of foam concrete D600 you will need:
- cement ПЦ500 Д0. 320.0 kg;
- sand. 200.0 kg;
- foaming agent for foam concrete. 1.0-1.5 l;
- water. non-rigid, tap.
To understand how to make foam concrete with your own hands, you should take a look at the table below.