Injecting cracks in brickwork - Working with Brick

Application

Restoring the integrity of buildings Protecting reinforcement and porous materials from penetration of air and moisture into structures To prevent water from entering the building

The use of technology is effective in restoring brick structures in the following cases:

Formation of cracks under increased loads When exposed to external factors, walls are partially or completely destroyed Masonry cracks due to uneven settlement of the structure

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Injection is included in major renovation works of buildings.

Sometimes the only possible action that can save a building from destruction is injecting cracks with a special solution. The walls of brick masonry structures, strengthened by the creation of reinforcing internal ties, are considered one of the universal methods for restoring load-bearing structures. This suggests that walls can be strengthened by injection for any type of deformation.

The essence of this method is that the cracks that appeared inside the brickwork are filled with special compounds. To carry out this work, holes are drilled that cross the detected cracks in the masonry and injection compounds are injected into them under high pressure. The difficulty is that the work is done blindly and therefore requires experience.

Concrete injection

For injection (or injection) of concrete walls, polymer-cement based materials are usually used.

The injection method consists of filling voids between adjacent structural elements (for example, between wall panels and floor slabs) with a special composition.

Injection of cracks can also be carried out (as well as injection of cracks in brickwork, foundations, etc.). The injection solution evenly fills all cavities, insulates and seals the seams, firmly connecting the elements of the supporting structure and returning them to their design strength.

In addition, injection improves waterproofing, creating a reliable barrier against water seepage and closing pores in concrete affected by dampness. Injection compounds can also be used to fill and seal utility gaskets, mounting holes for anchors, and for other purposes.

Materials used

They are divided into three types:

Liquids are defined as solutions that are free of particles and have a viscosity comparable to that of water. These include a solution of chemicals, synthetic resins and organic binders.

Unstable suspensions are an aqueous solution of cement and stone flour. Homogeneity is maintained during the mixing process. When mixing stops, they separate.

Stable suspensions - their sedimentation process is slower, this makes it possible to perform an injection before the filler begins to settle. The introduction of plasticizing additives makes it possible to achieve stability of the solution.

Before starting the repair of a brick wall, the crack is opened with the help of a scarpel, the crumbs of stones are cleaned, and washed with water. Then it is filled with solution.

Crack injection is performed in three stages:

Preparation of wellsInstallation and casting of injection tubesInjection of mixture

The number of wells is set on the basis of at least two pipes per crack.

Embedment depth -5-7cm, diameter -1.8-2.5cm. Wells are made at an angle of 60 degrees to the vertical surface to ensure good flow of the mixture into the masonry crack. The tubes are sealed with a 1:3 solution.

If the size of the cracks is large, then tow impregnated with resin or liquid glass is placed around the tube. Then it is minted. To attach the hose to the tube, its end is made to protrude 5-8 cm above the surface.

Two tubes are installed in the area to be treated; the mixture is injected into one, and the other for control. The mixture is pumped using a hand pump. For small volumes, a syringe is used.

The pressure when injecting the solution is up to 4 atm, and there are cases when the pressure rises to 12 atm. The duration of the procedures is no more than 10 minutes. The tubes are then removed 6 hours after the end of the injection.

Healing cracks in brickwork

Injection is performed by different types of solutions, and definitions are given by their names:

Silication Bituminization Smolization Cementation

Silication is carried out in two stages. The first is that liquid glass is injected through drilled wells, it penetrates through cracks into the structure and fills them. The second is to inject a solution of calcium chloride.

It reacts with liquid glass to form sparingly soluble calcium hydrosilicate and insoluble silica gel. Silication is used to heal cracks in structures that operate in aggressive environments. Bituminization - injection of grade 111 bitumen heated to 200-300 degrees, the humidity of the structure should be low to prevent vaporization.

Increases water resistance and corrosion resistance. Resmolization – injection of epoxy resin compounds. Increases structural strength and corrosion resistance.

Cementation of cracks is the most common method of healing cracks. A cement mixture of different compositions is used. This depends on the width of the cracks.

The cement mixture is prepared on the basis of Portland cement or well cement. Brands 400 and 500 are used. Pour cement into water and mix vigorously for 3 minutes.

The finished mixture is filtered through a sieve. The sieve is taken with holes 0.5-1mm. The mixture must be used no later than 30 minutes from the moment of production.

The condition of the brickwork during the operation of the building depends on many factors.

But the greatest influence on the masonry is, of course, atmospheric phenomena. Temperature changes that occur in autumn and spring, when the air temperature jumps from negative to positive during the day, have a particularly detrimental effect. But the cause of cracks and other defects may not necessarily be meteorological phenomena; it is likely that the building is subject to shrinkage and deformation of the soil foundation.

Moreover, if the brickwork was not laid according to the rules, the composition of the mortar was not followed, then microcracks appear in the masonry, which over time become larger and larger under the influence of water, which freezes in the cracks and causes internal stresses in the masonry.

There are different cracks depending on the degree of danger. The most dangerous for the load-bearing structure of a building are cracks with an opening greater than 0.2 mm, water-saturated cracks and cracks with leaks. Such defects must be eliminated first. It is very effective to eliminate such defects by injecting brickwork.

Injection of brickwork is a method of eliminating defects by pumping various binders into the damaged area. For example, acrylate gels or epoxy resins. You can also pump in special cement—microcement. This technology is also used to repair waterproofing of foundations and various underground structures.

Waterproofing for penetrating brickwork is made from high-grade cements with the addition of certain additives and quartz sand. Once in a crack, such concrete forms insoluble crystals that protect the cracks from water ingress, but at the same time are capable of allowing individual molecules to pass through in the form of steam, thereby allowing concrete to breathe. Typically, injection of brickwork is carried out during the restoration and repair of old buildings. If water enters through a crack, then the crack is injected with special polymer resins, which set very quickly and prolong the life of the masonry.

Why do problems occur with brickwork?

Despite the fact that brick walls are considered strong and durable, they crack and collapse, usually due to a violation of construction technology:

1) Foundation shrinkage, which occurs when the soil under the foundation is incorrectly assessed.

2) The load on the foundation is calculated incorrectly.

3) Regular wetting of walls followed by frost.

And as a result of violations of construction technology, brick walls begin to crack - first, small, unnoticeable cracks appear, which quickly expand, destroying the masonry.

There are two options here - to eliminate mistakes and re-arrange the walls, which, in fact, is not realistic, or to resort to the method of injecting brickwork.

Injection of brickwork - what is it?

In fact, there is nothing complicated about the method of injecting brickwork. This is the filling of voids in brickwork with special solutions that reinforce cracks and voids formed as a result of negative processes. The composition is pumped under high pressure through specially made holes in the wall - boreholes, into which injectors and special tubes - packers are inserted.

In addition, for injection of cracks in brickwork

you will need the solution itself, as well as a construction pump or syringe, and we’ll talk about this in more detail.

Brick masonry injection technology

First you need to prepare the wall for injection. To do this, holes are drilled in the wall at a distance of about 25 cm from each other.

Moreover, the depth of these holes is about 90% of the wall thickness, i.e. the wall is drilled almost right through.

Then comes the preparation of solutions, these can be polyurethanes or polymer solutions based on epoxy resin. After the preparatory steps, the fastening solution is directly injected into the brickwork through special pipes using a pump. Reinforcement is provided if necessary.

Thanks to the use of this technology, the brick wall is sealed, damaged areas are restored, and the strength of the walls increases up to 2 times.

Injection of brickwork allows you to quickly and efficiently carry out repairs and waterproofing, without removing damaged areas of the masonry.

Injection is the process of filling voids, cracks and various cavities with a special compound in brickwork.

The purpose of this technology is the ability to strengthen or glue the structure or prevent the penetration of moisture and harmful products that increase corrosion and violate the integrity of the object.

Cracks in brickwork can appear absolutely anywhere, and in some cases the integrity of the masonry can only be restored by injection.

The injection procedure is carried out by injection under pressure of a semi-liquid or liquid solution, which includes both cement and complex polymer components. Its content will depend on the specifics of the work and the task at hand, as well as the condition of the structure.

Especially often, such a need arises when reconstructing an existing building due to its physical wear and tear. During the work, it is necessary to change the level of loaded brickwork or repair damage to the wall. It is worth noting that traditional methods of one-sided building and strengthening of brickwork using clips or reinforced concrete jackets are effective and reliable, but require stopping the operation of the building while the work is being carried out.

Wall injection

During the redevelopment of residential premises, it is necessary to make openings in load-bearing walls quite often. In addition to metal structures, there is another way to additionally strengthen capital walls that have been subjected to this kind of influence. This is the injection of brickwork, concrete or masonry with non-shrinking, fast-hardening plasticized cement mortar under pressure (or other compounds, if necessary).

The emergence of this modern and efficient technology is due, among other factors, to the high wear and tear of the housing stock.

In our city there are many houses built in the 60s and 70s, which have almost exhausted the resource built into them. Loads, shrinkage, deformation, and disturbances during construction lead to the formation of cracks, voids and pores in concrete, cement and masonry. When water gets into them, corrosion (destruction) of wall materials, ceilings and fittings occurs. Therefore, when carrying out repairs or redevelopment of apartments, additional strengthening of load-bearing walls and ceilings will be useful.

Read more about strengthening openings in load-bearing walls with metal structures here

Technological sequence of work

Injection work is best done in the morning. At this time, the temperature of the structure does not exceed +5ºС, which allows for maximum crack opening. At the same time, you should not reduce the load on the brick wall during sealing, as this may partially close the crack, thereby reducing the quality of the injection.

The work is performed in the following sequence:

Surface preparation. At this stage, the brickwork is cleaned of bitumen, gypsum, oils, lubricants, paint, dust and other separating layers. Cement or lime mortar present on the surface must be removed with a grinding or sandblasting tool. Create rectangular 2x3 cm fines on the working surface along the entire length of the crack.

It is desirable that the jointing be dovetailed. On the wall on both sides, in a checkerboard pattern, drill channels along the treated surface in increments of 15...40 cm. In this case, the channel should cross the crack and be drilled at an angle from top to bottom. Its angle of inclination should be at least 10º relative to the horizon. Blow channels and cracks with compressed air. Install parkers. Moisten channels and cracks evenly with water.

This process must be carried out in advance so that the surface is evenly moistened at the time of injection. Prepare the repair mixture according to the instructions. Apply the repair mixture to the fines. In this case, they are used as permanent formwork and thereby prevent the mortar from leaking out of the cracks. Also seal the place where the parkers are installed. Introduce the mixture through the parkers, starting from the bottom up and maintaining a pressure of 1...2 atm. Dismantle the parkers. After the solution has hardened, clean the treated surface, and caulk the places where the parkers are installed with a repair compound.

Restoring a brick wall using this method can significantly reduce the consumption of metal, finances and, in comparison with traditional methods, reduce the time required for repair work. In addition, injection increases the strength of stone structures several times.

When examining brick structures, many are faced with damage to load-bearing structures, among which the most popular defects are cracks. If such damage is detected, it is recommended to repair it as soon as possible. This is due to the fact that cracks in the brickwork are conductors of cold, which can lead to freezing of the walls during the cold season.

The causes of cracks in brickwork can be: shrinkage of the house, lack of rain drainage on the roof, errors in the design of the building itself, and others.

Since the bulk of all defects are cracks no more than 6-8 mm wide, an injection procedure is used to seal them.