Reinforcement of the gas block under the windows. Reinforcement of aerated concrete blocks technology. Reinforcement materials

Recently, such building material as aerated concrete block has been very popular.

Aerated concrete blocks significantly increase the speed of construction and reduce the cost of building walls due to the fact that they do not require additional thermal insulation.

It is successfully used for the construction of both large buildings and low-rise buildings, since it has excellent technical characteristics, which increase several times if aerated concrete blocks are reinforced.

Advantages in use

To achieve the best result, it is necessary to reinforce the walls of the house in a complex manner.

Aerated concrete blocks, having a number of advantages, are attractive to a large number of consumers. First of all, this is their low cost, which significantly reduces the cost of building a house (about 40% cheaper than a brick building).

• the durability of the material allows you to stand up to 100 years or more;
• no less important advantages of this building material are its frost resistance, low weight, fire resistance, moisture resistance and environmental friendliness.

The composition includes cement, blowing agents and quartz sand, and lime, ash, gypsum and slag are used as additives. All the necessary components are mixed, diluted with water and poured into special forms.

Their susceptibility to any kind of processing is great: drilling, sawing, planing. It is quite easy to drive a nail into them, insert staples, but the material is strong enough.

It should be called its low resistance to deformations of various kinds. That is why it is very important during construction to reinforce the masonry from aerated concrete blocks.

Otherwise, during the operation of the building, cracks may appear on the surface of the walls, which will lead to a decrease in the quality and service life of the building.

Reinforcement features

Masonry reinforcement strengthens the wall to resist tension and compression from external factors.

Many builders are wondering whether it is worth doing additional strengthening of the masonry from aerated concrete blocks, which entails considerable material costs. There is no single answer in this case.

Some believe that it is enough to reinforce the bottom row of gas silicate blocks and openings, while others argue that every fourth row of masonry should be strengthened and a reinforcing belt should be created for all floors.

• reinforcement should be subject to those rows that are the most loaded: blocks under lintels, window openings and the first rows of blocks;
• at the wall, the length of which is more than 6 meters, every fourth row is reinforced (usually a special mesh is used).

The reinforcement itself does not increase the bearing capacity of the walls of the building, but it remains an important condition that must be observed during construction. This is due to the fact that gas silicate blocks are not able to work in tension, despite the fact that they have a high degree of compressive strength.

As a result, there is a possibility of cracks in the gas silicate blocks, which only spoil the appearance of the structure, without reducing its bearing capacity. It is quite difficult to disguise such defects even with the help of gypsum plaster.

The situation looks much more complicated if deep cracks appear in the seams of the masonry, through which a significant part of the heat will be lost. The reason for this will be uneven shrinkage of the house, especially during strong temperature changes or in the spring when the soil thaws, when the maximum load will be placed on the aerated concrete block, which will reduce the strength of the material.

Various defects can also occur due to improperly prepared cement-sand mortar, through which the walls of the house will be erected. To eliminate the occurrence of such a problem, it is necessary to use a special glue for, which, in combination with the mesh, allows the seams to be made as thin as possible.

Already at the design stage of the house, possible factors that will negatively affect the integrity of the structure should be identified, and measures should be taken to strengthen all weak points, for example, the support zone of lintels and various elements that experience significant loads.

Builders believe that the reinforcement will only violate the thickness of the masonry joints and lead to the appearance of cold bridges. But such a problem is easily solved if the installation is correct and small-section reinforcement is used.

Reinforcing belt

The reinforcing belt of the wall is calculated for each house individually: based on the design of the house, foundation, soil quality, etc.

If there are many controversial opinions about the reinforcement of aerated concrete, then there is no doubt about the creation of a reinforcing belt. This stage of construction should not be excluded for such purposes as cost savings.

The reinforcing belt contributes to the distribution of the load of the upper plates on the surface of the walls, ensures the stability of the structure from wind loads. Outwardly, it resembles a foundation (a kind of grid), which consists of a frame made of reinforcement.

The frame is poured with concrete and has a thickness of not more than 12 cm around the entire perimeter of the building. Quite often, builders prefer to replace such a structure with brickwork, which is often erroneous.

This is due to the fact that it will not meet the technical requirements that apply to the reinforcing belt, and will ultimately lead to deformation of the building (both the foundation and the walls).

Wall reinforcement

Strengthening the walls should take place as follows:

• for this, strobes are cut in the masonry surface on each side of the block at a height of 6 cm from the edge;
• to facilitate the work, they use a special wall chaser, which can be either manual or electric;
• before inserting the bars, all dust is removed from the finished grooves of the block with a building hair dryer. If it is not possible to use such a device (electricity is not supplied), use any brush;
• after that, the cleaned strobes are filled with glue, and reinforcement with a profile of no more than 8 millimeters is inserted into them. The glue, in turn, protects the reinforcement bars from corrosion, ensuring their reliable adhesion to the blocks;
• to make the masonry seams as thin as possible, reinforcing cages are used, which are paired strips of galvanized steel, the cross section of which is 8x1.5 millimeters.

In the set of additional elements, many manufacturers offer ready-made reinforced window lintels made of aerated concrete.

Their installation does not require making a strobe in the surface of the gas silicate block and the walls as a whole, since the frame is first fixed on a small layer of glue, slightly pressed and covered with another layer of glue on top.

If the wall is reinforced in the presence of lintels or windows, then the bars are laid across the entire width of the opening so that their ends extend 90 centimeters on both sides.

The process of creating a reinforcing belt resembles the construction of a foundation, when a reinforced concrete box made of reinforcement with a thickness of at least 6 millimeters is installed on the masonry surface.

A properly executed reinforcing belt is a single structure along the perimeter of the building. In order for the bond of the reinforcing belt with the masonry to be as strong as possible, wire rods or nails are driven into the upper aerated concrete blocks.

Then, formwork is erected around the entire perimeter and the entire structure is poured with concrete. It should be remembered that pouring must be done only once in order to ensure solidity of the structure. If such a moment is not observed, then the cement will seize in separate parts, and this will lead to a decrease in the quality of the reinforcing belt.

A negative factor in the design of the reinforcing belt is the formation of cold bridges through which a significant part of the heat is lost. In order to prevent the occurrence of such a problem, the niche is filled with any heat-insulating material, for example, mineral wool or polystyrene foam.

Thus, a favorable microclimate is created in the house both for human life and for the entire building as a whole from the point of view of ecology.

The construction of a reinforcing belt is influenced by many factors: the design of the house, the quality of the soil, and others.

Work Conclusions

From the foregoing, we can conclude that such a process as the reinforcement of aerated concrete blocks is very important for the quality of operation of the house and for its service life.

You don't need complicated tools either. Mainly:

• brush or hair dryer;
• brush;
• hammer;
• lacing;
• level;
• roulette;
• wall chaser;
• Bulgarian.

Reinforcement of the walls makes the geometry of the structure unchanged and prevents the structure of the building from further deformation, which will be quite problematic, and in some cases impossible to fix.

A series of articles on our website continues. We discussed:

• • • in the article there is a dispute between manufacturers of aerated concrete blocks and designers of buildings from this building material: is it necessary, in general, to reinforce the masonry of the wall from these blocks ?;
    • in the article the choice of mesh material for each specific case of masonry;
    • in the article full information about this building material.

So, having read the above articles, you have decided on the need to reinforce walls from aerated concrete blocks (in certain cases, walls are not reinforced from this material). And you know that all types of structural reinforcement of the masonry walls of gas-block buildings do not increase its bearing capacity, but only lead to a significant reduction in the risk of thermal shrinkage cracks.

Now you need to select the reinforcement material. Today we will give an answer to the question: what is the best way to reinforce aerated concrete blocks in different cases - with mesh or reinforcement?

Choosing the reinforcement material

Metal fittings have high mechanical strength and withstand heavy loads compared to non-metal. The total cross-sectional area of ​​the reinforcing steel bar should be only ≥ 0.02% of the same parameter of the reinforced aerated concrete masonry. Therefore, this material is widely used, but not everywhere.

The fact is that steel has several drawbacks, forcing, at the first opportunity (i.e., while ensuring the necessary mechanical strength of the masonry), to replace it with non-metallic reinforcement. Here is an incomplete list of these annoying "cons":

• • • susceptibility to corrosion. In an aggressive environment, which is mortar or glue, a metal rod or mesh can rust and lose its original strength;
    • the process of reinforcing with steel reinforcement has a high cost (transportation and handling costs, the cost of material and installation with strobing and fitting of rods in place, etc.);
    • steel reinforcement creates "cold bridges", which significantly increase the thermal conductivity of walls made of gas blocks.

Non-metallic meshes serve as a replacement for metal: propylene, composite and fiberglass. They have less mechanical strength compared to metal structures. But, they include a large number of polymer additives that are not subject to corrosion and the effects of an aggressive alkaline environment. In addition, these grids exclude the formation of "cold bridges", which significantly reduces the thermal conductivity of the wall (this is especially true if the wall is external).

Metal fittings

Rods and welded meshes are used as metal reinforcement. Rods are necessarily used when installing the entire vertical reinforcement circuit (lower and upper armored belt, vertical ties, etc.).

They are used to strengthen masonry under window and door frames, technological hatches, etc. Strobs are made for laying rods. To reduce the corrosion process, the metal rod must be recessed in the mortar (inside the gate) by at least 2 mm on each side.

The most complex, time-consuming and expensive reinforcement process is the process using welded meshes. If, to increase strength, a mesh made of large diameter reinforcement is used, this will lead to an increase in the thickness of the seam and, accordingly, a decrease in its strength. This is due to the fact that between the rows of blocks there will be a large amount of mortar. Therefore, nets with a rod diameter of Ø 3 ... 5 mm are used.

Technical characteristics of the grid are regulated by the GOST 23279-2012 standard “Reinforcing welded grids for reinforced concrete structures and products. General technical conditions". In accordance with it, the mesh is made of reinforcing wire of class Vr-1 and V-1 Ø 3 ... 5 mm. The dimensions are shown in the picture.

Non-metallic fittings

This type of reinforcement includes propylene, composite and fiberglass meshes. They are discussed in detail in the article. We will not repeat ourselves, but here we only note that the most widespread, due to its properties, is a composite mesh consisting of basalt rods.

Composite meshes are produced in accordance with the enterprise standard STO 5952-022-98214589-2013* “Basalt fiber meshes of the SBNPs “GRIDEX” brand. Specifications". This document prescribes the following cell sizes, mm: 25 x 25, 25 x 8, 50 x 50, 100 x 100, 150 x 150, 200 x 200. The width of the grid should be within, mm: 105 ... 5400.

Recommendations for reinforcing aerated concrete using masonry mesh

Aerated concrete is a warm, but rather brittle material that has low bending strength, and this causes cracks. Proper reinforcement strengthens the masonry, adding rigidity and resistance to cracking to the walls.

In this article, we will fully consider all the stages of reinforcing an aerated concrete house, starting from the first row and ending with the reinforcement of the pediment.

Stages of construction with the use of reinforcement:

1. Reinforcement of the first and every fourth row of aerated concrete.
2. Reinforcement of window sills.
3. Reinforcement of the jumpers themselves.
4. Armopoyas under the ceiling.
5. Reinforcement under Mauerlat.
6. Reinforcement of the pediment.

Previously, waterproofing was laid on the foundation, the first row of the gas block was laid on the mortar, and the plane of the blocks was leveled with a grater.

1. Make two strobes in a number of blocks.
2. Clear the row of aerated concrete chips and dust.
3. Bend the reinforcement under the strobes.
4. Fill the strobes with cement glue for aerated concrete.
5. Lay reinforcement in the strobes and smooth the plane of the blocks.

For reinforcement of rows of masonry, reinforcement with a diameter of 8 mm is usually used. At the corners, bending of the reinforcement is required. Reinforcement overlap must be at least 300 mm. It would be more rational to use longer bars of reinforcement, because this will result in fewer overlaps and more economical consumption of reinforcement.

The process of reinforcement under window openings is similar to what we wrote above. The only difference is that the reinforcement under the windows should go at least 900 mm from the edges of the opening.

The lintels must rest on the blocks a minimum of 250 mm on each side. Since the jumper collects the weight from the higher blocks, the increased load from the jumper is transferred to those blocks on which it stands.

Therefore, these blocks must be reinforced with two bars of reinforcement of 8 mm each. The length of the reinforcement should be 900 mm, but more is possible for reinsurance.

Jumpers can be poured independently, or you can buy ready-made. Ready-made aerated concrete lintels are sold in various sizes, both in length, width and height. For more information about jumpers, see our previous article, there is a complete overview.

Consider options for self-construction of lintels with reinforcement. The most popular and easiest way to create a lintel is to pour concrete into ready-made U-blocks.

The process looks like this:

1. A wooden support under the jumper is exposed.
2. U-blocks are laid on glue.
3. A heater is inserted from the outside of the jumper.
4. A reinforcing cage is installed from 4-6 bars of reinforcement.
5. It is poured with concrete M300-M350.
6. The jumper must rest on the blocks by at least 250 mm.
7. Longitudinal reinforcement with a diameter of 8-10 mm.
8. Transverse reinforcement (frame) - 6 mm.
9. Step between frames - 250 mm.
10. The main load is taken by the bottom reinforcement.
11. For the reinforcing cage, the protective layer of concrete is at least 40 mm.

The armored belt is an indispensable element of aerated concrete houses. The task of the armored belt is to create a rigid inextricable structure around the entire perimeter of the walls, as well as to evenly distribute the load from the ceilings and higher blocks.

Reinforcement in the armored belt is used with a diameter of 10 to 12 mm. For ordinary two-story houses, a reinforcement scheme with four or six bars of longitudinal reinforcement is used. The frame is made of 6mm reinforcement, the distance between the frames is about 250-300 mm.

At the corners of the armored belt, special clamps are used to reinforce the reinforcement, see the diagram below.

Reinforcement overlap of at least 300 mm. The width of the armored belt should be like that of a wall. The height of the armored belt is 200-300 mm. Do not forget about the insulation on the outside - 50 mm EPS.

The armored belt under the Mauerlat is less loaded, from which the requirements for it are less than for the armored belt for ceilings. Usually a square reinforcement scheme with 10 mm reinforcement is used. U-blocks are used as formwork.

• Studs should be 12 diameter.
• The distance between the studs is about 100 cm.
• The hairpin is fixed with a wire to the reinforcement cage strictly vertically.
• Before pouring concrete, wrap the studs with cling film or duct tape to keep the concrete from getting into the threads.

On the pediment you need to reinforce:

1. Window row.
2. row above the window.
3. Reinforcement of a row under the Mauerlat (armo-belt).
4. The upper edge of the masonry.

We wrote a large detailed article about partitions - aerated concrete partitions, where you will learn about reinforcement, anchoring with walls and other nuances.

Reinforcement of aerated concrete masonry is a necessary step that prevents the occurrence of temperature-shrinkage cracks. To reinforce the rows, metal or fiberglass reinforcement with a diameter of 8 mm or more is usually used.

It should be noted that the reinforcement of the masonry does not increase the bearing capacity of the aerated concrete itself, because the reinforcement works in tension, and for the bearing capacity, compressive work is needed.

Now consider what exactly needs to be reinforced in aerated concrete house.

1. first row of masonry;
2. every fourth row on walls longer than 6 m;
3. jumper support points, 90 cm from the edges of the openings;
4. areas under window openings;
5. armored belt for ceilings and for the rafter system;
6. other sections of the wall with increased load.

For more clarity, see the aerated concrete reinforcement scheme.

To lay the reinforcement in a row of a gas block, it is necessary to make two strobes, 20-30 mm deep and wide. The distance from the gate to the edge of the blocks must be at least 60 mm. For a smoother strobe, you can nail a wooden block, which will act as a guide.

For chasing, special hand-held chasing cutters are used.

1. Clean the grooves from dust with a brush;
2. fill them with glue for aerated concrete;
3. drown the reinforcement in the middle of the strobe;
4. align the plane of the blocks with a spatula.

Important: the overlap of the reinforcement must be at least 200 mm, and there must be a bend in the reinforcement at the corners.

Aerated concrete reinforcement technology (video)

For partitions, special aerated concrete blocks of smaller thickness are produced. The standard thickness of such blocks is 100-150 mm, but there are also 75 mm. To reinforce the rows, reinforcing bars with a diameter of 8 mm, or a flat punched strip, are used.

Usually, every fourth row of masonry is reinforced, but in areas with increased seismic activity, every second row is reinforced.

The gap between the partition and the ceiling should be 15-20 mm, and it should be filled with damping materials, for example, foam or expanded polystyrene.

To connect the partition with the adjacent walls, flexible metal ties or T-shaped anchors are used, which are fixed in every 3rd row of masonry.

Jumpers are also an integral part of the technology. The task of the jumpers is to withstand the loads that are transmitted from the higher elements of the wall.

Usually, to create a jumper, U-shaped blocks are used, in which reinforcement is installed and filled with durable concrete of the M300 grade. Fittings in lintels are used with a diameter of 8-12 mm. And the frame itself consists of four to six bars connected in the form of a square.

The U-blocks must be supported by a strong formwork which must not buckle under the weight of the lintel concrete. The lintel must rest on the wall at least 300 mm on each side. A week later, after pouring concrete, the formwork can be dismantled.

Blocks should be installed with the thickened side facing out. And it is even better to insulate the jumper with 30 mm thick polystyrene foam.

The gas blocks on which the jumpers will rest also need to be reinforced by 900 millimeters on both sides.

Note that ready-made aerated concrete lintels can be found on sale, such products are provided by Aeroc.

The condition of the armored belt is obligatory - it must be inseparable, because its task is to significantly increase the resistance of the walls to loads and prevent cracks.

There are two types of armopoyas, the first of which is interfloor, the second is underroof. The interfloor strengthens the walls and distributes the load from the ceilings.

The under-roof belt distributes the load from the entire roof over the box of the house, and also allows you to level the plane and fix the Mauerlat.

The reinforcement scheme of the armored belt consists of four working rods of metal reinforcement with a diameter of 10-12 mm. Working reinforcement is fixed by a square of structural reinforcement. The installation step of the square should be 300 mm.

Do not forget that the reinforcing cage must have a concrete protective layer of at least 40 mm. The overlap of the reinforcement rods must be at least 50 cm. The bending of the reinforcement at the corners is obligatory. Also remember about the insulation of the armored belt with polystyrene foam. For the armored belt, it is recommended to use concrete grade M300, which must be poured at a time.

We described the detailed process of reinforcing the armored belt with all the pictures and diagrams in our previous article - armored belt for aerated concrete.

Tools for reinforcing aerated concrete

1. Estimating brush;
2. brush;
3. wall chaser;
4. carriage or bucket;
5. hammer;
6. Bulgarian;
7. lace;
8. formwork;
9. yardstick;
10. building level.

Gas silicate blocks have become widespread in the construction of private buildings and industrial facilities. The builders were convinced of the high performance characteristics of the popular material. Consumers are attracted by the affordable price and reliability that gas silicate has. However, there is a difficulty - the material is susceptible to the effects of stretching.

You can fix the problem by reinforcing the gas silicate blocks. This allows you to increase the strength of the structure, strengthen the walls, corners, openings of the building, prevent the appearance of cracks, ensuring a long service life of the building.

Reinforcement of masonry from gas silicate blocks is necessary, since the walls are subject to volumetric deformations associated with shrinkage, soil reaction and temperature factors. Openings, thresholds, as well as walls, on which cracks appear under the influence of tensile forces, are especially susceptible to loads.

In a relatively short period of time, gas-liquid brick or aerated concrete has gained great popularity among builders.

Let us consider in detail how the popular gas silicate is reinforced, we will dwell on individual sections of the building, the technology for performing work that can be done independently.

Material Properties

Gas silicate has many positive characteristics:

• the correct geometry, which allows laying with glue, which eliminates cold bridges and saves heat;
• a high level of strength, allowing the use of material for the construction of main walls;
• reducing the load on the foundation of the building, which is associated with a small mass of products;
• reduced coefficient of thermal conductivity, contributing to a comfortable temperature regime of the room;
• light weight with increased volume, which facilitates transportation and speeds up the work related to masonry;
• no negative impact of blocks on the health of others;
• ease of processing, allowing you to change the size and configuration of products.

Processing in the production process gives high strength to the buildings being erected

One of the indisputable advantages of gas silicate is its low price, due to which the material is widely used by private developers. However, products need reinforcement.

On the need for amplification

Along with a complex of positive aspects, the material has negative aspects. Walls are prone to volumetric deformations caused by the following factors:

• The susceptibility of blocks to the effects of tensile forces.
• The hygroscopicity of the material, which, absorbing moisture, swells.
• Temperature differences, as a result of which the massif narrows and expands.
• Insufficient rigidity of the foundation, causing shrinkage of the structure.
• Heaving of problematic soils, characterized by closely spaced aquifers.

To avoid the negative impact of negative factors, it is possible to reinforce the walls from gas silicate blocks, which prevent cracking, increase the strength and service life of the building under construction.

Let us consider in detail which problem areas of the building under construction should be strengthened.

Areas to be strengthened

When using gas silicate, to increase the strength characteristics of the object under construction, reinforce gas silicate blocks in problem areas.

The construction of aerated concrete walls must be accompanied by the obligatory laying of a reinforcing frame

The following areas are subject to reinforcement:

• the area between the base of the building and the lower row of masonry, which perceives the mass of walls, ceilings and roofs. They provide the strength of the base with reinforcement or steel mesh, which contributes to the proportional distribution of forces on the foundation and increases the bearing characteristics of the first row of blocks;
• supporting surfaces of the masonry being erected at intervals of every 4 levels of installed blocks. Masonry mesh, along with steel reinforcement, allows you to perform reliable reinforcement of these areas;
• wall surfaces of increased length, as well as the side surfaces of the building, perceiving increased loads. An additional reinforcement circuit is provided by the masonry mesh. This allows you to increase strength, compensate for wind loads and achieve thermal insulation of the building perimeter;
• the upper level of the walls, perceiving the load of the truss system and the roof of the building. The use of steel reinforcement makes it possible to form a monolithic reinforcement contour around the entire perimeter of the walls, which evens out point loads and evenly distributes the forces transmitted by the truss system to the masonry surface;
• areas located in the openings. Using steel reinforcement located in the prepared grooves, they strengthen the sections above the lintels, which perceive significant loads from the mass of the masonry located above them.

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Consider the materials that allow you to perform the reinforcement of gas silicate blocks.

Based on the possible loads, several types and approaches are used in laying reinforcing elements.

How are products enhanced?

Reinforce masonry from gas silicate blocks using the following materials:

Let us dwell on the features of the implementation of individual stages in the most problematic areas.

Features of masonry reinforcement

Reinforce masonry from gas silicate blocks in the following sequence:

• mark the surfaces by drawing two parallel lines, each of which is 6 cm from the side surface;
• according to the marking, make grooves using a wall chaser or grinder;
• clean the grooves from dust, moisten the surface;
• cut the rebar to the required length and place it in the cavity;
• connect the fittings into a solid circuit by welding or knitting wire;
• fill the grooves with the bars with mortar, ensuring an equal layer thickness for laying the next row.

If the masonry is reinforced correctly, then the house will never crack and will always be strong enough.

Using the grid

Wanting to provide strength, they also reinforce with the help of a mesh. It is possible to purchase a commercially manufactured mesh or make it at home. The mesh can be immersed in the grooves or placed in the solution. Gas silicate is reinforced with masonry meshes made of various materials:

• Galvanized wire, which has increased strength, but is prone to corrosion.
• Fiberglass, having insufficient strength, used only for reinforcing walls.
• Basalt fiber, not prone to corrosion, the strength characteristics of which are close to metal structures.

The use of mesh to strengthen gas silicate walls allows you to strengthen buildings and create a favorable microclimate.

Reinforcement of openings

Reinforcement of walls from gas silicate blocks in the areas of openings is carried out by two methods:

• the use of steel rods with a diameter of 4-5 mm located in the gas silicate, repeating the configuration of the corners and the supporting part of the jumper. Install the bars in pre-made grooves;