Foam concrete blocks: dimensions, characteristics

Private houses are increasingly being built from foam concrete. Since the material is relatively new, there are many questions. The first thing that needs to be dealt with is how foam blocks differ from gas blocks. Next, you need to figure out what the dimensions of the foam block are, what density and mass they are. Let's talk about all this further.

Foam concrete and aerated concrete - do not confuse

There are two porous building materials of artificial origin on the market - aerated concrete and foam concrete. Their composition is similar. It is a mixture of cement and sand with the addition of water and a foaming agent. As a result, the mixture acquires a porous structure, which increases thermal conductivity and reduces weight. These are the main advantages of this type of materials.

But not everyone understands the difference between foam concrete and aerated concrete. It is not surprising: they are very similar in appearance, even they have a common GOST. The difference is mainly in the features of the technology. The characteristics of both materials are very close and they belong to the same group - aerated concrete.

Foam blocks and gas blocks are not visually very different

What is the difference

The difference between foam and aerated concrete in the used foaming agent and the order of adding it.

• In the manufacture of aerated concrete, aluminum powder is added to the dry mixture of cement and sand, everything is thoroughly mixed. Then water is added. As a result of the reaction (aluminum powder with cement components) forms hydrogen and aluminum oxides. Hydrogen "carbonates" the mixture, resulting in the formation of cells of different sizes - there are large ones - 3 mm or more, and small - 1 mm or less. With a low production level, a heterogeneous block structure in height is possible. This heterogeneity is reflected in thermal conductivity and sound insulation characteristics. Aerated concrete of normal quality has a more or less homogeneous structure and stable characteristics. So when choosing this material, the level of production is of great importance.
  

  Gas blocks production technology

• A chemical or organic foaming agent is added to the foam concrete in the form of a ready-made foam. First, dry components are mixed, water is added to them, foam is introduced into a uniformly mixed solution, which gives pores of approximately the same size. That is, foam blocks are more uniform in structure (in the photo on the left). In addition, the bubble shell is thicker and more durable.
  

  Foam block production technology

If we consider the materials from this side, then foam blocks have more advantages. But there are other nuances that must also be taken into account.

Features of production

When choosing building materials, especially such as aerated concrete, you need to pay attention to even the smallest details. Because it is they who ultimately affect how warm and durable the structure turns out to be. These subtleties will be described in this section.

1. Production technology.
   • Making foam concrete is so simple that it can be done in a garage. It is enough to buy a foaming agent, and the rest of the components are readily available. The mixture (cement + sand + water) is mixed in any container, a foaming additive is added. Further, the composition is poured into molds. Ripening of blocks occurs naturally - in the air. That is, you can do without special equipment, quality control is conditional - you need to adhere to known proportions and technology. But you really want to save money ... Therefore, there is a large number of foam blocks on the market, the qualities of which are far from GOST.
     

     Foam concrete has a more homogeneous structure

   • Aerated concrete is mixed just as easily, but there are two types - autoclave and non-autoclave. Non-autoclaved is also dried in the open air, but has not the best characteristics.Autoclaved aerated concrete undergoes a hardening process at elevated pressure and temperature. As a result, blocks are obtained with increased strength. They are more expensive, but much stronger.
2. Accuracy of geometric dimensions.
   • Aerated concrete blocks are produced in two ways. According to one technologist, the composition is poured into ready-made forms. These blocks have a size difference of up to 3-5 mm. Using another technology, large-format blocks are formed, which are then cut to specified sizes. The difference in the size of such material is minimal.
     

     Strength of foam concrete of different density

   • Foam concrete is poured into ready-made forms. There is no other technology. Accordingly, the difference in block geometry can be significant. It is corrected by increasing the masonry joint, which reduces the thermal insulation characteristics of the masonry as a whole. So focus on geometry when choosing. If the blocks are almost the same (GOST permits deviations of 1 mm), there is a hope that the technology was followed.

If we consider these materials from this point of view, then autoclaved aerated concrete with minimal discrepancies in dimensions is more preferable. Masonry is made of such material using special glue. It is applied in a layer of a couple of millimeters, since the ideal geometry allows this. Since a seam with a wall made of this material is a cold bridge, the wall turns out to be very warm (due to the small thickness of the seam, heat is better preserved in the building).

When using foam blocks with a large difference in size, a conventional solution is used for masonry. The adhesive is too expensive to be applied in large layers. When using a cement mortar, the costs are much less, but the thermal insulation characteristics of the building cannot be compared - they are much lower.

Density and mass of foam blocks

Foam concrete can have different densities. It is designated by the Latin letter D, after which there are numbers from 300 to 1200 in increments of 100 units. The higher the density, the greater the mass and strength, but the lower the thermal insulation characteristics. Therefore, according to the area of ​​use, foam blocks are divided into three categories:

• from D300 to D500 - foam concrete insulation blocks. They are used as insulation (for example, when insulating a balcony or loggia), they are not able to withstand any significant load.
  

  Price list of one of the firms. Cut blocks are more expensive, but much easier to work with

• from D600 to D900 - structural and thermal insulation blocks. They are also often called construction. They can withstand some load, while they have good heat retention properties. These are the ones that are usually used in the construction of private one-two-story houses. The best choices are D600 and D700. The wall thickness when using blocks of this density is only 35-45 cm (for central Russia), and without the need for additional insulation.
• D1000 to D1200 - building blocks. They are capable of carrying significant loads, but the thermal conductivity is low. Additional insulation is required. Little is used in private construction.

The density of foam blocks affects its mass. In fact, the brand displays the mass of one cubic meter of material. For example, a cubic meter of D400 foam blocks will weigh about 400 kg, a cube of D700 density blocks will weigh about 700 kg.

How much a cube of foam blocks weighs depends on the density of the material

Why "about", because the manufacturing process allows some error. A little more mass is considered normal - in the range of 10-15%. But at the same time it is necessary to look so that there are no foreign inclusions. Some manufacturers mix in broken brick or crushed stone to reduce cost. Because of this, the mass becomes a little more, which is generally not critical. But these additives greatly reduce thermal conductivity, which is not good at all. And this is no longer foam concrete, but incomprehensible building blocks with unknown characteristics and it is not clear how they will behave during operation. So when buying, be sure to be interested in the mass, and if possible, break up a couple and see what is inside.

Foam block dimensions

The production of aerated concrete blocks is regulated by GOST 215 20-89. It defines the characteristics and standard sizes, but there is also a postscript that the parameters can be changed at the request of the consumer.

By appointment, foam blocks are wall and partition walls. Walls are used when laying load-bearing walls. They are usually 600 * 300 * 200mm in size. Some firms produce blocks with a length of 625 mm. The rest of the parameters remain the same. In that case, the size of the most popular foam block looks like this 625 * 300 * 200 mm.

The dimensions of the foam block can be not only standard

In any case, for a wall 30 cm wide, one block is sufficient. Moreover, if you use the D600 or D700 brands, it is quite possible to work alone. One block weighs not so much - from 21 kg to 26 kg (21 kg - less dense, 26 kg - more).

There are wall blocks of different formats. Here are the main dimensions of the foam block, which is used for laying load-bearing walls and partitions:

• 600 * 300 * 200 mm - the most popular size of foam blocks;
• 600 * 300 * 250mm;
• 600 * 300 * 300mm;
• 600 * 300 * 400 mm.

With a density of D600 or D700, it is quite possible to work alone with foam blocks 200 mm wide, 250 mm. Their weight is 20-35 kg. You can do it alone. Even larger ones, 300 mm wide and even more so 400 mm, are already work for two. It is even possible to use a lifting mechanism.

There are large-format block panels. You can work with them only with the use of lifting equipment - at least a winch. But construction is progressing very quickly. The dimensions of the large format foam block are as follows:

• 1000 * 600 * 600mm;
• 1000 * 600 * 500mm;
• 1000 * 600 * 400mm;
• 1000 * 600 * 300 mm.

That is, blocks with a width of 300 mm and 400 mm during the construction of a building in central Russia are stacked in one row. Since their height is 60 cm, there will also be few rows.

The dimensions of the foam block are selected depending on the type of building and wall

There are also small-format blocks. They are usually used for insulation, in some cases for the construction of walls - if a partition is needed of a small thickness, or it is decided to build from small-sized foam concrete blocks. The dimensions of the foam block of small thickness are as follows:

• 600 * 300 * 100mm;
• 600 * 300 * 150 mm.

It is easy to work with them, since they are light and lightweight, especially if they are used as thermal insulation. The density of the foam concrete is then 300 or 400 units, so that the weight of one foam block does not exceed 10 kg.