Concrete blocks are often used for private and commercial construction. The most popular type of this artificial stone is aerated concrete, or in other words, autoclaved porous concrete. It possesses unsurpassed energy saving and heat insulating properties, low weight and is easy to handle. In addition, it can be easily done by hand.
The technology of manufacturing concrete blocks for individual needs and on an industrial scale will be the topic of today's article.
Materials for production
The use of blocks of aerated concrete in construction has many advantages.
We list the main ones:
- one 30-kilogram block can replace about 30 bricks at a time, which affects the time the building was erected;
- low weight of porous concrete allows you to build private housing without using cranes and other special equipment;
- autoclave gas blocks can be easily processed using conventional plumbing tools.
The simplicity of the production process makes it possible to produce the necessary amount of this building stone directly on or near the construction site.
All you need is an instruction describing the whole process, and the raw material:
- quartz sand.
Note! To obtain the porous structure of aerated concrete, a suspension of aluminum powder is used. It is an active substance that can harm human health. Do not forget to use safety devices.
Devices and mechanisms
Not so long ago, the complexity of the technology did not allow the manufacture of various concrete blocks at home, without the use of specialized production lines. Currently, the situation has changed dramatically. There is equipment for: for the manufacture of aerated concrete blocks, for cinder blocks, for bricks and so on.
Modern installation is a device, the size of not more than a standard concrete mixer, the price of which makes it very affordable for most homegrown builders. To it will need to purchase only the special form of your chosen configuration. (See also the article Concreting the Foundation: Features.)
In the case when aerated concrete is not produced for own needs, but for the purpose of subsequent sale, it makes sense to pay attention to other equipment:
- semi-automatic production lines that produce 2-4 cubic meters of finished products per day are good for individual entrepreneurship or medium-sized enterprises;
- automatic production complexes, allowing to produce up to 100 cubic meters of aerated concrete blocks in 24 hours - suitable for a large enterprise engaged in the production of building materials.
The main part of the process
Production of aerated concrete blocks begins with the mixing of raw materials. Considering that this building material has a porous structure and low weight, from a small volume of sand, cement and lime, a sufficiently large number of prefabricated elements are obtained.
For convenience, we will break down the process into several stages:
- Lime, water, cement and quartz sand are poured into a concrete mixer where they are thoroughly mixed.. After 5-10 minutes, a small amount of aluminum powder dissolved in water is added to the same place. This substance, entering into a chemical reaction with lime, contributes to the release of hydrogen. It is this gas that forms in the block pores with dimensions from 1 to 2 mm, which occupy the entire volume of aerated concrete.
- Immediately after adding the aluminum suspension, the mixture is poured into special forms, where it expands, increasing in volume several times..
- So that the pores are evenly distributed, and the aerated concrete is faster to freeze, the forms are placed on a special table or platform, where the future aerated concrete is subjected to prolonged vibration loads.
- At the last stage, using the metal strings, irregularities are cut off from the upper edge of the finished products, and the blocks are calibrated to the desired size..
Tip! In order to quickly cut and calibrate aerated concrete, you can use special milling machines.
Equipment for the manufacture of aerated concrete blocks includes autoclave chambers. In them, the hardened blanks are subjected to 12-hour steam treatment at a temperature of 190 degrees Celsius and a pressure of 12 kgf / sq. cm.
After this procedure, aerated concrete acquires greater strength and homogeneous structure, and also gives minimal shrinkage after construction.
It can be used as:
- heat insulator;
- sound insulation;
- material for load-bearing walls.
By the way, the excellent energy-saving qualities of aerated concrete, which has an excellent thermal conductivity, allows you to build houses of blocks up to 400 mm thick without using additional materials that retain heat (mineral wool, polypropylene, foam).
In the manufacture of aerated concrete, it is not necessary to autoclave it. But this material will be less durable and has worse characteristics.
|Indicator||Autoclave aerated concrete||Non-autoclaved aerated concrete|
|Shrinkage, mm / m||0,3||3|
|Durability, kgf / sq. cm.||28||10|
Properties of finished products
Aerated concrete obtained as described above has the following properties:
- low density (comparable to the density of solid pine) - it is 5 times less than that of solid concrete and 3 times less at brick;
- compressive strength, which allows erecting 2 and 3 storey buildings from aerated concrete;
- moisture absorption, which does not exceed 20%, which is comparable with the same brick;
- frost resistance is 2 times greater than that of a brick;
- high thermal conductivity - 2 times less than that of pine, 15 - in concrete;
- excellent sound insulation properties - with a wall thickness of 300 mm fully isolates the sound power of 60 dB;
- maintains influence of an open flame with the temperature of 900 degrees Celsius for 4 hours;
- aerated concrete is easy to cut with a regular wood saw;
- the cost of its purchase or manufacture is lower than that of similar materials.
Remember that in the independent production of aerated concrete, it is necessary to strictly observe the proposed production technology. Otherwise, the finished stone will not meet the standard for physical properties, which can even lead to the collapse of the building. (See also the article Heater for concrete: features.)
Learn more about the technology of production of various building materials will help the video in this article.