Types of aerated concrete: classification by strength,

Construction technologies are currently reaching a qualitatively new level of development. This is manifested not only in the quality of the buildings being erected and in the reduction of time spent on it, but also in the use of various innovative materials.

One of them is aerated concrete. What types, brands and variations of this material exist? This will be discussed below.

Production of aerated concrete

For the first time this type of building material was invented in the nineteenth century by the Czech scientist Hoffmann, who received a patent for his technology. Its essence was to add to the concrete solution of carbon dioxide and chlorine-containing salts, which contributed to the formation of air pores in the finished blocks.

But on an industrial scale, this artificial stone was produced only in the United States due to two entrepreneurs, Aulsworth and Dyer, who used aluminum powder that reacts with lime, resulting in the formation of hydrogen. He also gave the blocks a well-known porous structure.

This technique is the basis of modern technological processes. Aerated concrete Aeroc, which is one of the most common materials, is produced according to a similar principle.

Material classification

Despite the fact that the principle of production of this kind of artificial stone is the same, many improvements have been made to the process over time. Now, for the needs of builders, various blocks of durability, shape and type are manufactured.

Grades of aerated concrete by strength

Marking of aerated concrete blocks is made on the basis of their density and, accordingly, strength. The fewer air bubbles in the finished product, the greater its brand.

Note! The quality of aerated concrete does not depend on the brand. Each of the varieties of this product is intended for use in a particular branch of construction.

Consider the most common:

1. Aerated D600. Due to its high strength and ability to retain heat, it is widely used for building facades of various buildings.
2. Aerated D500. Used to construct monolithic and block walls of high-rise buildings and cottages.
3. Aerated D400. Less durable, but has excellent thermal insulation properties. Used for masonry partitions and improve the heat-shielding performance of the walls.
4. Aerated D350. Very fragile material, which due to the highly porous structure, retains heat very well. Used as insulation. It is extremely rare.

The finished blocks of aerated concrete are divided into three types:

• for the construction of walls and other engineering structures;
• combined - are used as the main and (or) heat insulating material;
• thermal insulation - the purpose of this type of building material is clear from the name (another frequently used term is foam-concrete).

The first type is a subclass characterized by high strength of concrete products and high weight of materials. Marked from D900 to D1200.

Technical characteristics of the combined aerated concrete blocks allow the construction of buildings and structures up to three floors in height without the use of additional insulation. It is often used to build houses and cottages with their own hands. It has brands from D500 to D900.

And the last point - the material for the arrangement of partitions. Instructions for the construction of interior walls requires the use of aerated concrete of different thickness: 75, 80, 100 and 200 mm. It is light, but fragile enough. Markings - D350, D400, D500.

Forms of end ends of aerated concrete blocks

To facilitate the work of builders, improve the strength and thermal insulation properties of future buildings, the ends of the finished concrete blocks during their production can be given a different shape.

Note! To make such blocks easier to classify, they are often called the letters of the Latin alphabet, whose form they repeat. For example, H aerated concrete means that this type of block in profile is similar to the English letter N.

Let us dwell on the most popular varieties in more detail:

1. Blocks parrot-combs One of the high-tech varieties of aerated concrete. Instead of flat ends, this kind of artificial stone has grooves and ridges, which when masonry walls are connected to a kind of castle. The reliability of the joint is so high that when a layer of plaster is applied to the walls outside and inside, it is not necessary to cover the end seams with an adhesive. Otherwise, the use of cement mortar is unavoidable, since heat loss will occur through bare joints in the finished building.
2. U-shaped blocks. Used for the construction of hidden structural elements. For example, stiffness belts in monolithic structures. The empty space inside the block is filled with metal fittings and concrete.
3. Aerated NN. The usual scope of application - arrangement of formwork around the perimeter of the wall. Considering that a block of this form has weak thermal insulation properties, it is necessary to lay expanded polystyrene into the voids formed, otherwise it will be difficult to maintain a comfortable temperature condition in the finished building.

Types of blocks on the production technology

Modern aerated concrete is produced by two types of technologies:

• autoclave - in this case, the mixture for the production of finished building blocks is processed and hardened in special autoclave furnaces, where a temperature of 190–200 degrees Celsius and a pressure of 10 to 12 bar are reached;
• non-autoclaved - concrete mix with various additives is poured into special forms and remains there until complete solidification.

Autoclave artificial stone has a higher strength and low heat-conducting performance. Due to the special conditions created by high temperature and pressure, gas bubbles in the finished block are distributed more evenly.

In addition, special automation controls compliance with all engineering standards, both in composition and in block shape. However, the price of autoclaved aerated concrete is higher.

Tip! Do not purchase cheap aerated concrete for construction. Most likely, production rules were violated during its manufacture, which would not slow down affecting the quality of the erected wall or partition.

Dimensions of aerated concrete blocks

The minimum thickness of the finished concrete block is 75 mm. Naturally, such dimensions do not allow the manufacture of the bearing walls of the building. Therefore, blocks up to 200 mm in size are considered partition walls. All that is higher - wall.

You should carefully calculate the size of the blocks, since the minimum deviation in one direction or another can significantly increase or decrease the estimated cost. For example, standard blocks for building walls are 240 and 300 mm. Given that the difference is not significant here, the choice is obvious - a thickness of 240 mm is more attractive.

The thickness of the walls for the erection of which aerated concrete is used depends on this: 48 is a double block, 24 is a single block.

Non-block aerated concrete

In addition to the block elements described above, there is a so-called growing aerated concrete, which is used for the construction of monolithic structures using metal reinforcement. It is made directly at the construction site, since after the water is added to the mixture, the concrete structure hardens in a matter of minutes, which prevents the transportation of the finished mortar by means of road transport.

There are two ways to produce a growing aerated concrete mix:

• use of finished semi-finished product, where the required amount of water is added before use;
• the use of the mixture for the production of concrete (sand and cement), diluted with a special frother (most often with aluminum powder).

Handle foamed concrete with care. After adding water and pouring into the formwork, it can not be subjected to mechanical stress. Otherwise, the not completely frozen foam may fall off, which will negate the efforts of the builders.

Another disadvantage is the long construction period. The subsequent layer of the growing aerated concrete can only be poured onto the previous layer that has completely hardened and gained strength. And cement foam hardens for a long time.

Conclusion

Having decided to use aerated concrete blocks as the main building material, carefully analyze all existing varieties and choose the one that best suits your needs.

A video in this article clearly shows some of the nuances of the specified topic here, look!