Aerated concrete or gas silicate: what is better and how is it different?

Building materials are found today the most diverse, and sometimes it is difficult for non-specialists to understand their features. A striking example is the confusion between gas silicate and aerated concrete, which have fairly similar characteristics. But this similarity in no way means a complete identity.

Energy and heat coming through the pipes of the main heating rise in price year after year more and more. Therefore, there is an increasing demand for structural materials that thoroughly hold back heat. Optimal results are achieved with the use of insulating varieties of concrete. Misunderstanding arises due to identical parameters and close fields of use.Sometimes even experienced builders can not quickly determine the difference between gas silicate and gas concrete. Some manufacturers increase the chaos, calling their goods in an arbitrary way.

To understand the specific features of the materials, you need to figure out for a start how exactly they are formed. Aerated do, using Portland cement or other cement, which is added sand and lime. But gas silicate belongs to the group of cellular silicate nature of concrete. It is formed from a combination of sand with lime (64 and 24%, respectively). All the rest comes from additional additives and water.

Thermal characteristics of aerated concrete block are created due to the porous structure. It is possible to form it in production using the swelling of the main mixtures due to the introduction of substances that form pores. The cavities of the finished product are bubbles with an external cross section of 0.1–0.3 cm. These cavities account for 70 to 90% of the total volume of the material. If the design is done according to the rules, the cells filled with air are dispersed in a uniform way.

Any concrete should certainly harden.Strengthen gas silicate block helps heat treatment with steam. To do this, the workpiece is placed in an autoclave, where it is affected by a temperature of from +180 to +200 degrees. At the same time, the pressure reaches 8-14 atmospheres. The situation with aerated concrete is different; it can be hard both in the autoclave and in the open air, depending on the nuances of the technology.

Pressure treatment is considered preferred because it has the following characteristics:

• increases the rate of setting;
• makes the material stronger;
• guarantees stable geometry;
• Radically reduces shrinkage when used.

Both gas silicate and autoclaved aerated concrete are almost pure white. But the gray color clearly indicates that there is aerated concrete in front of the consumer that was processed without applying pressure.

Evaluation of any of the listed materials is carried out taking into account such parameters as:

• density (specific gravity);
• water absorption;
• heat transfer;
• resistance to compression - characterizes the mechanical strength;
• resistance to frost - measured in the number of cyclic freezing and thawing;
• water vapor permeability;
• the total thickness of the masonry.

Familiarization with the main technological characteristics shows that aerated concrete and gas silicate are not inferior to each other in the following parameters:

• the passage of steam through the thickness of the material;
• protection against fire;
• suitability for cutting by hand saws;
• environmental properties;
• prevention of cold bridges;
• cost;
• suitability for finishing with a wide range of decorating plasters.

All this does not mean, however, that aerated concrete and gas silicate really coincide with each other in all respects. In this case, the difference is already evident in the composition of adhesive solutions offered by manufacturers of various units. Glue is a combination of sand and cement, the specific properties of which are determined by additional additives. Only through such additives can compensate for the speed of installation. A classic astringent solution, even a very good one, will not help in this case.

When comparing different materials and trying to evaluate which one is better, it is important to understand that all these judgments are relative. Pressure-improved gas silicate blocks will definitely be of high quality, but they will have to pay a lot of extra money for their merits.Low density gas structures become brittle, but this is “justified” by increased protection from heat loss. Aerated concrete, obtained without an autoclave, is rather unstable, but it can be obtained independently. Such blocks are easy to do directly on the construction site, saving money. Gas-silicate unit with identical processing modes differs from aerated concrete for the better in almost all properties, except liquid absorption, therefore gas silicate is used only where the humidity does not exceed 60%. Under more severe conditions, the material degrades too quickly.

This means that the facades must be covered from atmospheric moisture.

To solve this problem using tools such as:

• paint on the facade;
• plaster;
• siding;
• plaster in the form of a thin layer.

Another can be applied facing brick with a gap for blowing air (the gap is 300-400 mm). It is recommended to cover the outside wall with an extended roof overhang. The bigger it is, the less dangerous are the precipitations.All finishing materials that are applied on top of aerated concrete and gas silicate should have a good level of vapor permeability. If this condition is not met, it is necessary to prepare excellent ventilation.

The passage of steam through insulation, paint or plaster should be more intense than through the construction material. Recommended additional insulation using mineral wool. When finishing or heat protection is performed in several layers, steam penetration into each next one of them should be more active than into the previous layer. Failure to do so may result in condensation. Soon there will be pockets of mold.

If you have to fix hanging furniture from gas silicate or aerated concrete, use dowels. Aerated concrete blocks are additionally attached using anchor bolts. Under both types of structures, foundations should be created with thoroughly calculated parameters and dimensions. It is also desirable to prepare a waterproofing. Hardening is performed on the first and on every fourth row. It is advisable to reinforce more door and window openings.

Independent production of aerated concrete for the most part is done in forms, divided into sizes. Buying complex and expensive cutting devices does not justify itself. It is important to remember that with an identical average density of the substance, the gas silicate retains heat better. Therefore, it is recommended to use it in the coldest places. The choice of aerated concrete or gas silicate is not reflected in the speed of construction.

Gas silicate is preferable where there is a need for enhanced sound insulation. But his fire resistance is somewhat weaker, as is the service life. The aesthetic characteristics of the gas silicate is higher than that of aerated concrete, but it is worth remembering that everything is so clear only when comparing materials without external finishing. Therefore, this circumstance is important only with maximum savings. Summarizing the above, we can conclude: the final choice depends only on personal priorities, with the exception of individual cases when the situation allows you to make an unequivocal decision.

When special geometric accuracy of the sizes and forms is needed, the choice in favor of a gas silicate is fully justified.When it is planned to lay on the mortar of cement and sand, you need to use cellular concrete, not subjected to treatment in the autoclave. The advantage of gas silicate blocks is an improved grip between parts having grooves and ridges. Protect both materials from moisture should be immediately after the completion of shrinkage structures. Important: when buying ready-made blocks (both gas silicate and aerated concrete), preference should be given to products of well-known companies.

On the advantages of gas silicate or aerated concrete blocks, see below.