Mixes for the repair of reinforced concrete structures. Compositions for the repair and restoration of concrete and reinforced concrete structures. Characteristics of repair mixtures

Reliability and can serve for a long time. But, it is possible that he is subject to destructive external influences. After a while, cracks and irregularities may appear on it, so in the article we will consider how to get rid of such damage using repair mixtures and compounds.

What it is

The restorative composition consists of:

• cement;
• sand;
• fillers;
• all kinds of additives that give the solution the qualities necessary for its strength.

In dry form, repair mortars for concrete can be applied immediately, for this, water is added to them and mixed thoroughly.

With the help of such solutions, shortcomings on concrete structures are eliminated, in particular:

• gender;
• stairs;
• bridge
• wall;
• road.

Also, dry repair compounds are usually used for the following purposes:

• repair work of the main structures that perform the function of bearing: concrete beams, floor slabs, columns and others;
• implementation of repair work of the road surface (aircraft take-off runways, parking lots), concrete floors at industrial enterprises, warehouses;
• as surface protection from .

To date, there is a diverse selection of concrete repair compounds, ranging from various manufacturers and ending with the properties of the funds. The price of mixtures also has a wide range.

Compositions designed to eliminate defects are divided into two main types:

• molding, which are used for horizontal surfaces;
• thixotropic - for vertically located planes.

Tip: to increase the reinforcing performance, it is necessary to add fiber to the composition of the repair agents.

How to choose a mixture

When choosing, you need to consider several indicators, namely:

• what damage;
• What is the surface defect?
• its operating conditions.

During the repair work on critical concrete areas, the use of reinforced fiberglass is most appropriate. In addition, there are special tools designed to carry out repairs in a short time, which harden quite quickly.

Tip: apply each layer no thicker than 35 mm. And, if the reinforcement in concrete structures is bare, it should be treated with an anti-corrosion primer.

In order to level the horizontal surface, a dry poured concrete repair mortar is used. It has a liquid consistency compared to thixotropic.

The casting composition must simply be poured onto the concrete surface. In this case, one layer can be 100 mm thick. The composition has minimal shrinkage, it firmly covers the surface and instantly seizes.

When repairing cracks in concrete, which often occur on its surface, the same mixtures are used that were used to level the plane. When choosing them, consider the conditions for further operation of the structure.

In the manufacture of such a mixture, the composition may contain different components that give the product certain characteristics, for example:

• frost resistance;
• hydrophobicity;
• shortening the setting time of the solution.

How to level the floor

You can level the horizontal surface with your own hands. However, the work will require considerable effort, certain knowledge and methods, but, adhering to technology, you can independently achieve the required quality. To level the floor, you will need a cement-sand screed.

Below are the instructions for working with it:

1. The first step is to clean the floor from dust and dirt.. Remove the old coating, treat the surface with a primer for a more even distribution of the solution.
2. Determine the highest point from which the floor leveling will begin.
3. Install beacons, for which metal corners, pipes or profiles are suitable. Place them so that they are on the same level.

Tip: It's best to do this with a laser level.

1. Start pouring the screed. At the same time, its layer should be up to 40 mm thick. Pour the solution that was previously mixed in a metal or plastic container onto the surface, then continue leveling the fill using the rule.

After pouring, let the screed dry well for a couple of weeks. The next day after completion, if the solution has managed to gain some hardness, remove the beacons, and fill the seams with grout.

Tip: during drying, cover the screed with polyethylene film. Moisten the surface with water from time to time to avoid cracks and strengthen the screed.

It is possible to repair horizontal surfaces made of concrete using a self-leveling agent. It is used if there are small defects or irregularities up to 3 mm on the surface. The result is a completely smooth surface.

How to remove potholes

It happens that potholes form on the surface of concrete.

1. First, make an incision along the perimeter of the defect, its depth should be up to 20 mm. Use a grinder with a diamond blade for this purpose.
2. Remove excess concrete with a chisel or hammer.
3. Remove any remaining dirt and dust. To better remove all debris, you can use sandblasting equipment or a vacuum cleaner.
4. Apply an epoxy primer to the clean surface to help it bond to the concrete.

1. Fill the pothole with a special mixture, which can be repair compounds for reinforced concrete.
2. Remove excess mixture from the surface, level it with a rail or a rule.

The patch must be left until it is completely dry. In this case, the tool will be strong enough. The last step is sanding the patch.

Conclusion

For repair work, it is better to use special dry mixes instead of a standard concrete mortar. Such repair agents have certain properties that will provide the coating with adequate strength. The video in this article will help you find more information on this topic.

Repair mixes for concrete are used when we need to repair surface damage without dismantling and re-pouring. Of course, the strength of the structure may decrease somewhat, but still the final state will be much better than before the repair.

Below we will tell you what mixtures can be used to seal cracks and cracks, how to prepare such products yourself, and what to look for when using them.

General issues of repair of concrete structures

The most common damage

Concrete is a fairly durable material, and it is for this reason that it is widely used in construction. However, such surfaces are also subject to wear, so sooner or later they need to be restored.

As a rule, in everyday life we ​​encounter either damage to concrete load-bearing structures (foundations, plinths, walls), or defects in the floor screed.

The most common problems include:

• Dusting - finely dispersed destruction of the surface layer. It occurs as a result of a violation of the filling technology, as well as with a significant intensity of operational loads. Eliminated by applying film-forming compounds - sealing.
• Cracks - are formed when strong loads are applied to a small area, as well as during temperature deformations. In addition, concrete can crack during shrinkage.

Advice!
To avoid the appearance of deformation and shrinkage cracks, it is necessary to take measures at the stage of preparing the structure for pouring concrete.
For this, various damper tapes, expansion joints, etc. are used.

• Traces of mechanical damage - chips, potholes, holes etc. This also includes traces of structural elements - mortgages, beacons, formwork parts.
• Level differences due to uneven shrinkage of the base.

And if in the latter case it is necessary to carry out a large-scale restoration of almost the entire floor, then if cracks or potholes appear, the concrete repair mixture will help restore the surface.

Types of mixtures

To perform repairs, a variety of compositions are used. Their range is very extensive, but still it can be divided into two groups. Material features are easiest to analyze by studying the table below:

As for the material, non-shrink cement is widely used for the manufacture of such compositions, as well as polymers - epoxy and polyurethane. All funds in this category are characterized by a fairly rapid hardening, therefore they are used for express recovery - when there is no time to wait for a full set.

An additional advantage may be the presence of fibers in the composition of the repair mixture - steel or polymer fibers. When solidified, it strengthens the edges of the damaged base, significantly increasing its strength. True, the price of such reinforcing agents will be slightly higher.

Self-manufacturing

If you do not want to spend money on buying branded material, then you can easily make a mixture for repairing concrete surfaces with your own hands. Of course, its efficiency will be somewhat lower, but it is quite suitable for domestic needs.

For cooking we need:

• PVA glue or bustilat, diluted with water in a ratio of 1: 3.
• Cement - 1 part.
• Sand sifted through a fine sieve - 3 parts.

The material is being prepared immediately before the start of the repair.

For this:

• Pour the cement-sand mixture into a container with a wide neck.
• Pour the adhesive suspension into the dry material, gradually mixing the solution manually. It is important not to overdo it with water - the composition should be quite dense.
• When all the material is in the container, we take a drill with a mixer nozzle and knead the composition until completely homogeneous. As a rule, three to five minutes are enough for this.

Troubleshooting Method

Foundation preparation

Usually, any mixture for repairing concrete surfaces is accompanied by instructions that clearly regulate the process of its use.

• First, we need to inspect the damaged area and roughly estimate the amount of material that we need.
• Then we remove fragments of concrete, dust, debris that got there, etc. from the crack. For small defects, a stiff brush can be used, while large damage can be more conveniently cleaned with a high-pressure sandblast or water jet.
• To secure the edges, the crack can be deepened 20-50 mm below the natural fracture line. In the process of jointing cracks, cutting of reinforced concrete with diamond wheels is often used, which makes it possible to obtain perfectly even edges and eliminate all weakly holding areas.

Advice!
On longitudinal cracks, experts recommend cutting transverse grooves in increments of about 20 cm for more efficient fixing.

• Particular attention should be paid to the reinforcement cage. We clean all metal parts protruding beyond the concrete coating to a shine. Then we apply an anti-corrosion primer to the cleaned bars to prevent oxidation of the material during the hydration of the repair mixture.
• If the depth of the defect exceeds 50 mm, then it is necessary to lay additional reinforcement in it. The fittings are mounted in such a way that the metal is subsequently covered with a layer of mortar no thinner than 20 mm.

After completing all these works, we dedust the area again. Then we moisten all surfaces, trying, however, to prevent the accumulation of large drops.

Preparation and application of the composition

Self-prepared concrete repair mortar can be applied immediately. But the compositions of industrial production must be properly diluted with water.

Only in this case, the material will acquire the characteristics necessary for effective filling of the seam and polymerization:

• As a rule, both flowable and thixotropic mixtures require a relatively small volume of liquid. On average, 120 to 250 ml of water is consumed per 1 kg of dry material.
• Cool water in a minimum volume (the exact numbers are indicated in the instructions) is poured into a container or a concrete mixer. Then we fall asleep dry component, gradually mixing the material.

Note!
Manual processing does not provide the desired uniformity of the product, so it is imperative to use an electric mixer.
For small volumes it is allowed to use a drill with a special nozzle.

We apply casting agents in this way:

• We mount the formwork along the perimeter of the restored area. It is desirable that its height be at least 50 mm more than the planned coverage level.
• Pour the prepared fluid mixture onto the concrete, evenly distributing it from one edge to the other. This sequence of actions will avoid the capture of air bubbles.
• Vibration compaction of the compound is not required in most cases. To remove air pockets at the junction of the surface and the formwork, it is enough to draw a metal strip around the perimeter.

With thixotropic agents, we act differently:

• We collect a small amount of material on a spatula or grater.

• With force we press the composition into the crack, filling it in one pass by 15-25 mm.
• After waiting some time for the polymerization of the layer, we repeat the processing until the defect is eliminated.
• We smooth the surface with a moistened steel trowel, trying to mask all the protrusions and irregularities. Re-leveling using the same tool is carried out after the mixture has set, i.e. at least half an hour after application.

In order for the repair composition not to crack, it must be kept moist for a day, and in the heat - up to three days or more. To do this, periodically spray the restored area with water from a spray gun or hose, after which we cover it with polyethylene or burlap.

Comments:

Repairing cracks in concrete is sometimes a high priority task. Defects and cracks are formed both in old structures and in newly built ones. Before proceeding to get rid of cracks, you will need to choose the most convenient way.

Cracks in concrete can occur due to moisture or deformation of the concrete product, shrinkage or stress.

Sealing cracks in concrete

Defects, cracks can form both in new concrete structures and in those that have been in operation for some time. The reasons for their appearance can be very different. If you do not eliminate them, but only carry out minor repairs, the structure will gradually collapse.

Cracks can be, for example, deformation, shrinkage. Deformation cracks are those that result from thermal expansion or improper shrinkage. They can appear in structures with a small load, which are not load-bearing. These can be screeds, bases for walkways and porches, etc. Their opening is most often small and amounts to a few mm, so they do not affect the strength of the structure. They can decrease or increase due to changes in humidity, air temperature, shrinkage of bases, soils.

Shrinkage cracks can be caused by the fact that the concrete mixture sets and dries too quickly. Crack opening may be uneven, but not large. Sometimes concrete is covered with a web of small cracks that are barely visible to the eye. But if the surface is wetted, cracks immediately become clearly visible. They do not pose a threat to the strength of concrete, but through them the structure will be saturated with moisture.

Reasons for the formation of cracks in the concrete structure:

Repair of cracks is carried out by filling the depth with synthetic solutions with the addition of resins.

1. seating. For example, a foundation made of concrete may settle due to the fact that the soil is compressed unevenly, the load is different for different sections. A material such as concrete is not so strong that it does not change under loads, and in the process of its hardening, due to uneven loads, it may crack.
2. Corrosion. The impact on the components of carbon dioxide, carbonization, salts creates the most favorable environment for cracks to appear in the material.
3. mechanical loads. Various kinds of destruction can occur due to accidents, possible seismic activity, excessive vibrations, and so on.
4. Other influences. The material may be slowly destroyed due to the influence of salts, acids or alkalis.

Here are the main reasons due to which defects can occur in the material. Any problems of this kind require immediate elimination, otherwise cracks in the concrete will occur again and again.

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How to repair defects in concrete

Starting to close up cracks, first determine how you will do it. Thin cracks in concrete in most cases are simply primed, plastered or painted over.

When unstable cracks appear in unloaded structures, they can be sealed with silicone or other elastic sealants.

Crack sealing is carried out mainly by filling the depth with synthetic mixtures with the addition of resins that have a low viscosity. Holes are drilled along the crack, they must be placed diagonally, towards the defect. After that, bushings are placed in the holes and the working mixture is forced through them. The resin is then pressed in using an injector. This method helps to ensure good strength of the structure, and it is able to work as a whole.

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Sealing and injection of concrete

One of the methods most often used to eliminate defects is called sealing, the second is injection. He is considered the most professional and has the best effect. But to use it, you need to have certain working skills. This method is more expensive, but the results are impressive. The procedure is carried out as follows: special compounds of polymers or cement mixtures with additives are pumped into the formed seams, voids, cracks in concrete under pressure. They are able to quickly fill the space, after which they harden.

Another method is called crack sealing. First, the cavity should be cleaned of crumbling concrete particles. Then the space is tapped with a chisel. The excess layer of concrete must be removed 300 mm up from the crack and the same - down. After processing, crumbs and dust are completely removed from the site and the prepared repair composition is applied. It is prepared from a solution of sand and cement, adding polymer components there. Epoxy resin can be used in this composition. The treated surface at the last stage is covered with a polyurethane sealant.

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What repair compounds are more popular

Preparation of the composition of epoxy resin, quartz sand and hardener.

If, when examining the surface where work is to be carried out, it was decided to remove a layer of concrete with defects, it will then be necessary to apply a new layer of cement-sand mixture in its place. To do this, you need to carefully consider the development of its composition. It is necessary to select components depending on the size of damage, cracks. For example, the composition for sealing large defects will be different from how hairline cracks are treated.

The most popular for repairing the surface of concrete are the following compositions: concrete, with the addition of epoxy, cement-sand. Concrete mix is ​​most effective when it comes to sealing significant defects and cracks. It consists of butadiene-styrene latex and Portland cement, which are mixed in a ratio of 1: 2.

When performing the mixture, the composition should turn out to be slightly fatter than the previous one. The mixture of concrete after laying must be kept for about four days. Another mixture that can be used for such work is made up of sand and cement. It is more convenient to use for sealing small cracks. The composition is made by mixing Portland cement and sand, the ratio is 1:3. Styrene-butadiene latex can be used for the sealer. The coating is waterproof, the adhesion of the mixture to the surface improves. If the cracks are very small, less than 100 mm in depth, the application of the composition is best done using a pneumatic apparatus. This results in a better seal. You can choose shotcrete for embedding - it will provide good strength for possible compression.

Concrete is a complex composite material with a capillary-porous structure, operating under high mechanical, climatic and chemical loads. Due to these characteristics, artificial stone is prone to corrosion, deformation, shrinkage and destruction. Modern repair technologies make it possible to restore almost any degree of destruction, ensuring the quality and durability of concrete structures.

Concrete and reinforced concrete structures and structures against the background of severe operating conditions can acquire a number of damages.

The main ones are the following:

• general loosening of the structure. Such damage is characterized by the appearance of the smallest defects, which significantly reduces the strength of the artificial stone and affects further degradation;
• destruction of surface layers. This includes the delamination of the protective layer, the formation of voids and cavities on the surface;
• destruction formation, loose areas, cracks in deeper layers ;
• corrosion of fittings, mortgages.

General loosening of the concrete structure is a formidable harbinger of dangerous deep destruction

Fighting methods

The choice of concrete repair technology depends on the type of damage detected after the analysis of the structure. When choosing a technical solution, they are guided by modern technologies and materials that ensure the extension of the service life of concrete from 15 to 40 years.

When choosing a material, they rely on the following indicators:

• the degree of responsibility of the structure, bearing capacity, loading;
• depth of defects;
• operating conditions (dynamic loads, aggressive media, temperature, humidity);
• location and accessibility of the structure;
• scope of work;
• aesthetic requirements.

In addition, a number of requirements apply to all repair systems, in particular, good fluidity, thixotropy, non-shrinkage, low w/c ratio, good adhesion.

Repair of significant defects

If significant damage has formed on the surface, the base is poured with new concrete. Initially, the damaged area is cleaned to benign concrete, then the repair is carried out.

Most often, solutions based on high-strength cements with complex additives, or special fast-hardening cements, polymer solutions, fiber-reinforced concrete are attracted.. In this case, it is important to ensure high adhesion between the main structure and the repaired area. For this, special methods are used that strengthen the bond between the old and new concrete.

Ordinary heavy concrete is used for complete or partial repair of structures, pouring solid reinforced concrete jackets, applying repair layers with a thickness of more than 10 cm.

The area to be re-concreted must be buried and of sufficient thickness.. The best results are obtained with steel mesh reinforcement. The material is shot to the base with dowels or firmly fixed in other ways.

Old concrete is cleaned, washed. It is required to expose the grains of the aggregate, to obtain a rough surface. In a number of situations, an additional layer is used that works on adhesion (polymer acrylic, epoxy compositions, cement adhesives).

Dry mixes (Emaco, BIRSS, Osnovit, Knauf)

Dry mixes are prepared on the basis of cement, which works for high compatibility with concrete. Such materials provide all the prerequisites for high-quality repairs, which is fully confirmed by repeated experience of use.

The thickness of the repair layer for one application varies from 5 to 50 mm, which is typical for vertical / horizontal bases, on ceiling surfaces the thickness is taken as 30 mm. The maximum effect is achieved with the use of primers, primers.

Types of dry mixes for the repair of artificial stone:

• for structural repair of concrete and reinforced concrete structures at t above +5 degrees;
• the same, but at negative temperatures;
• for protection and waterproofing;
• for non-structural repairs (not affecting the geometry and load-bearing capacity).

Scope of application of dry mixes: accelerated repair, sealing of defects, including concrete, reinforced concrete structures, roadbed with concrete coating, sealing of industrial floors, joints

Advantages:

• high adhesion between old and new concrete;
• high compressive strength;
• no shrinkage (which is achieved by complex additives);
• elimination of shells, chips, cracks, 50-100 mm deep;
• concrete repair is carried out in the shortest possible time.

Disadvantages:

• low shelf life;
• high price;
• application only at positive temperatures.

Specifications

Thixotropic compounds (MAPEI, BASF, Sika)

This is a kind of dry mixes based on high-strength cement, additives, fractionated sand. Materials containing polymer fiber have shown particular effectiveness.

The main difference from typical mixtures is that the composition with thixotropic properties is successfully used on ceiling, vertical, horizontal planes without formwork. When hardened, it is high-strength concrete. Application thickness 10-35 mm.

Scope of application: repair of monolithic, prefabricated concrete, viaducts, bridges, canals, tunnels, objects of special and general construction purposes, repair of joints, protective layers.

Advantages:

• abrasion resistance;
• high adhesion to concrete;
• frost resistance, water resistance.

Disadvantages:

• high price;
• application at positive temperatures.

Specifications

Thixotropic compounds suitable for structural and non-structural repairs

Compositions based on epoxy resins and other polymers (Elakor, Technoplast, KrasKO)

Such materials are used in various types of concrete repair, in injection work to protect concrete from various kinds of influences (polyurethane, acrylate, epoxy). Rigid, semi-rigid, elastic solutions are taken into work.

Polymer materials require preparation and priming. Application is carried out with a smooth spatula or polyamide rollers, or with special injection equipment.

Repair acrylate compositions are used to seal cracks, chips, increase strength, waterproofness of the base. To enhance the positive properties, you can fill it with quartz sand.

Two-component epoxy compounds are used in cases where it is necessary to restore the bearing capacity of concrete, create an adhesive layer, and repair cracks. Two-, three-component polyurethane are effective in localizing leaks, blocking the flow of water.

Scope of application: repair of concrete floors for industrial and civil purposes, warehouses, garages, workshops, hangars, etc.

Advantages:

• high rates of chemical and mechanical resistance;
• high wear resistance;
• fire safety;
• good adhesion to the base;
• waterproofing, waterproofing.

Disadvantages:

• low viability.

Specifications

Secondary waterproofing of concrete, repair (SCHOMBURG, Protexil)

To protect structures from operating conditions, apply:

• hydrophobic impregnations (silane, siloxane, polysiloxane) - in fact, this is a surface treatment until a base with a water-repellent effect is obtained;
• impregnations on a mineral and polymer, polymer-cement basis - provide hardening and a decrease in surface porosity.

Equipment and accessories for repair work

For high-quality implementation of work, you should have the appropriate tools, equipment, equipment and devices.

Concrete pre-cleaning will require sandblasters, high-pressure cleaners and the high-pressure stations that create them

This group includes the following:

• mobile power plants of the required capacity;
• compressors;
• perforators and jackhammers;
• construction vacuum cleaners;
• grinders, grinders;
• chisels, scrapels, shovels, trowels;
• metal brushes;
• buckets, containers;
• devices for finding reinforcement, thermometers, devices for determining the viscosity of the solution, the strength of concrete;
• films to protect the solution from drying out, overheating.

Concrete repair technology

Regardless of the type of material chosen, the workflow follows a single technological sequence.

The bottom line is this:

• preliminary preparation of the base;
• cleaning of reinforcement, cleaning of reinforced concrete structures, laying of additional reinforcement (if required);
• dedusting;
• if necessary, formwork is placed, surfaces are moistened;
• preparation of working solutions;
• application and maintenance.

Preparation of concrete surfaces for repair

Before the start of any manipulations, the place of work is protected, lighting is organized, mechanisms, tools and equipment are prepared. All equipment is checked for readiness for idling. The method of preparation depends on the degree of concrete damage, the volume and type of defects, and the type of repair composition. Prior to preparation, if required, eliminate leaks in the repaired area.

Preparation can be done in the following ways:

• mechanical- use perforators, jackhammers, picks, pneumatic chippers, shot blasting, sandblasting machines, grinding equipment and cutters.
• thermal- use oxygen or propane burners. Surface heating should not exceed 90 degrees. This method is good for a small depth of damage (up to 5 mm), if the concrete is contaminated with rubber, oils, residues of other organic compounds. Heat treatment is always followed by hydraulic or mechanical;
• chemical- use special formulations. The method is implemented only where it is impossible to apply the mechanical method. After etching, the surface is always rinsed with water;
• hydraulic- use high-pressure apparatuses (12-18 MPa and 60-120 MPa). The method is used in almost all cases, with the exception of those where an increase in air humidity is undesirable.

If there are areas with defective concrete on the base, it is cut down with perforators, chippers, concrete breakers. They produce a layer with insufficient thickness (up to 20 mm), a width of 10-15 cm, acting along the reinforcing bars, a peeling protective layer, loose concrete with shells, structural damage.

After cutting, the surface should be rough and embossed without dust, stone chips and other contaminants.. Fittings damaged by corrosion and not amenable to cleaning are replaced. The rods protruding to the surface should be cut out. In some cases, an integrated approach is possible in the course of preparation.

Preparation of repair mixtures

Repair compositions based on dry mixes are prepared at the work site using mortar mixers or concrete mixers (forced or gravity). If a small amount of solution is required, it is prepared in a clean container using a drill with a mixing attachment.

The amount of the mixture is prepared taking into account the viability. When mixing with water, they are guided by the manufacturer's recommendations, strictly observing the ratio of water and cement material. On average, 0.12-0.13 liters of water is required per 1 kg of dry powder.

When preparing solutions, it is necessary to have a clean container, volumetric utensils for dosing the components, a viscometer, a thermometer.

Preparation of injection solutions:

• the required amount of epoxy resin is poured into a clean container;
• introduce additional components;
• the composition is mixed until a homogeneous consistency.

Immediately before applying the solution, a hardener is introduced, followed by finishing kneading for 2-3 minutes.

Preparation of sealing mastics:

• the required volume of epoxy resin is placed in a clean container;
• plasticizer, hardener are introduced;
• the composition is stirred;
• in the process of mixing, the filler is introduced into the mixture until a paste-like homogeneous consistency is obtained.

Preparation of composite materials:

• mixing primers and adhesives is carried out using a low-speed drill (300-500 rpm);
• the components are mixed in accordance with the manufacturer's recommendations, taking into account the viability of the composition.

Repair of defects made during construction

Elimination of such defects can be implemented in two ways: with the installation of formwork and without. In the latter case, small defects are eliminated (at a depth of not more than 3 cm), filling the cavities with ordinary concrete, mortar, polymer concrete. More serious damage is always filled with concrete with formwork, reinforcement.

With the old base, the hardened layer is fastened with pins (anchors). To improve the adhesion of old and new concrete, the surface of the first is treated with primers.

Concrete mortar is fed to the repair site manually with the following compaction by deep vibrators. If bulk solutions are used, vibrators are not used. The compaction process is considered complete if laitance has appeared on the surface and air has stopped escaping.

When manually applied, the repair material is spread with trowels, spatulas. Permissible layer thickness 5-50 mm.

The repaired area requires care, for which a polyethylene film or film-forming composition is used. After removing the formwork, all protrusions are removed, possible defects are sealed. Voids, cavities in the places of technological seams are eliminated by injection (polymer cement, cement compositions).

Inactive (non-breathing) technological, shrinkage, temperature and structural cracks are eliminated by surface sealing (polymer-cement pastes based on acrylic polymers or epoxy resins). Active cracks are eliminated with sealants, if necessary, by combining sealing with injection work.

Concrete repair using composite materials

Such work is carried out in cases where it is required to strengthen the structure without a significant change in geometry and weighting the structure. Preparation is carried out using a sandblaster or grinder. Further the work area is primed with an epoxy primer. Drying of the layer is 3-12 hours.

A compressor is used to blow the base from crumbs and dust.

After preparing the repair composition, it is applied to the surface with rollers or brushes. If quartz sand is introduced into the mixture, as a rule, trowels, spatulas are used. Next, the surface is leveled and smoothed.

If defects were found in the concrete, they are filled with a working composition flush with the floor level. Alignment is carried out with a sharp spatula. When the finished layer has gained the required strength, grinding is carried out, pores are sealed. In this case, they work with epoxy resin, which is applied with a roller with an average consumption of 0.2 kg / sq.m.

Protective layer repair

Before starting work, the base must be thoroughly cleaned of corrosion products, paint, dirt, weak concrete. If it is required to restore strength and strengthen the structure, additional reinforcement is carried out using steel anchors.

The technology can be adopted as follows:

• development of damaged areas with a diamond circular saw;
• removal of damaged concrete with high-pressure apparatuses or pneumatic tools;
• cleaning of fittings with high-pressure apparatuses or by chemical means;
• protection of fittings with anti-corrosion composition;
• additional reinforcement with mesh (if the embedment depth exceeds 5 cm);
• saturation of the old foundation with water;
• application of repair mortar by spraying or spraying. If the amount of work is small, use a trowel;
• leveling the layer with a trowel;
• surface care with film-forming compounds.

Crack Filling Technology

Cracks in concrete are repaired only after the causes of their formation are discovered and eliminated. The development of cracks must be completed. Embedding begins when the waterproofing defects are corrected, after the release of moisture accumulated in the defects(substrate must be dry).

The surface should not contain chips, shells, peeling areas, cleaning of old paint, dirt is carried out by means of water jets.

The method of repair depends on the magnitude of crack opening, the impact of damage on the bearing capacity of concrete:

• if the damage is minor (so-called hairline cracks), as a rule, a protective coating is sufficient;
• if the concrete contains cracks, plus there are prerequisites for further opening and the formation of new ones, the installation of "seals" is implemented. In this case, a chamber 5-7 cm deep and 15-20 cm wide is made on both sides of the defect in order to expose the reinforcement and set the gap. Next, cleaning is carried out with compressed air and the chamber is filled with fiber-reinforced concrete.

Serious defects are sewn together with flat anchors and covered with a protective layer 2 cm thick. This method of sealing is often combined with the injection of cement mortars into cracks

Internal waterproofing of cracks

If the crack is inactive, a chamber is cut along its length and filled with polymer solutions. The minimum chamber width is 4 mm. This technical solution is relevant mainly for shallow defects.

If inactive deep cracks are found, the repair method discussed above is supplemented by injection. If the defect is active, a mandatory sealing is carried out with the participation of sealing thiokol mastics. If the crack is deep, sealing cords are additionally used. This is a proven method of waterproofing.

Injection concrete repair

When implementing injection works, it is required to have data on cracks. To determine the depth of the defect, ultrasonic devices are used, the opening is determined by special devices. Access to defects is preliminarily prepared, tools and equipment are connected.

General repair recommendations are as follows:

• dry cracks, the opening of which does not exceed 0.3 mm, are sealed. An elastic material is taken into work, which will not lose its tightness under the operating conditions of the structure;
• cracks filled with cement leaching products are also subject to sealing, since the internal space may be impervious to injection compounds;
• if the defect is periodically flooded, jointing is carried out in the form of a groove, 15 mm deep, 20-40 mm wide. Next, filling with polymeric material is carried out;
• on cracks with a higher opening, on wet cracks, injection is carried out. The work takes compositions that can interact with water.

The composition of the solution for injection, injection technology depend on the type of structural element, the type of cracks, the temperature of the surrounding work and concrete. As a rule, for small defects, low-pressure technology (pressure 0.2-0.3 MPa) is used with a pneumoinjector.

When injecting deep cracks (depth over 45 cm, width over 1 mm), high-pressure injection technology is used. This will require a hand pump, packers. Efficiency was shown by light portable sediments of the membrane type with regulation of the supply of the composition into the cavity.

Such work includes the following steps:

• installation of packers;
• expanding expansion seal;
• introduction of the composition into the package to failure. The solution must exit the adjacent packer;
• after completion of work and curing of the solution, the removable part of the packer is removed;
• the hole is caulked with a repair compound.

Injection begins with the fact that the packers are removed nipples, leaving only the lower extreme (pioneer). Next, prepare the working solution, pour it into the pump. A hose is put on the lower pioneer packer and the compound is injected.

Solution for injection is prepared taking into account its viability

They work until the solution appears from the funny packer. Then the nipple is moved to the adjacent packer, isolating it. Then they work with this packer and so sequentially fill the entire defect. The injection rate of the solution should increase gradually, but not higher than 40 bar. The normal operating pressure is 20 bar.

Shot concrete

Shot concrete materials are successfully used for restoration and repair work. Thus, the sealing of shells, cracks, and destruction is carried out. The base must have a bearing capacity, be strong, clean. It is acceptable to torketirovanie reinforced concrete surfaces, work on a metal mesh. Before starting work, the concrete is moistened, but the presence of puddles is unacceptable.

If there are microcracks, potholes on the base, they will give access to chlorides, water, carbon dioxide, which will accelerate corrosion processes. It is recommended to carry out sealing with anti-corrosion compounds before applying a protective coating. Leaks are eliminated with the help of hydraulic seals.

Work order:

• the application of the working mixture is carried out using compressed air or a pneumoconcrete pump;
• in one cycle, a layer is applied, up to 3 cm thick;
• the surface is treated in layers. The number and thickness of layers are determined by the project.

Safety measures during the implementation of repair work

Safety standards for the production of repair work are established by SniP 12-03-2001, SniP 12-04-2002 "Labor safety in construction", safety rules, safe operation of electrical installations, compressors, pressure vessels. All requirements are met regardless of the chosen technology.

Concrete repair work is carried out using ladders, scaffolds, safety belts. Particular attention is paid to safety when working with epoxy resins and polymer concrete. Workers must complete a fire safety training course. Everyone is given individual protective equipment, overalls.

Persons who have reached the age of 18, have passed introductory briefing, training, and are admitted to repairs for health reasons are allowed to perform work.

Repair cost

The average costs for the restoration of concrete structures start from 2500 r / m3 taking into account preliminary preparation, installation of formwork and reinforcement. The most economical repair option is the use of polymer systems. This method will require costs - from 100r / m3. Injection work remains very expensive - from 2000 r / linear meter.

findings

The choice of concrete repair technology depends on the actual state of the surface, operating conditions and tasks. The optimal recommendations are given in the table.

Repair of concrete in the parking lot is shown in detail in the video:

Concrete is a material used in all areas of construction, the main advantages of which are high strength, reliability and durability. But over time, even concrete structures are destroyed. There can be several reasons for the appearance of cracks, chips, deformations: violation of the ratio of elements during mixing, mechanical influences, environmental influences, loads, and so on. To restore the material, special mixtures are used.

Repair mixtures are used for quick restoration of various concrete structures, restoration of their geometric parameters and performance characteristics.

Repair compositions for concrete are of two types:

• casting;
• dry.

To fill pre-prepared cracks and recesses, casting mixes for concrete are used. They have the ability to expand and a high degree of adhesion to concrete, stone and reinforcement, and when solidified, they practically do not shrink. Filling all the free space, the solution reliably seals and strengthens the repaired surface. Casting mixtures are used in the restoration of horizontal surfaces.

Restoration of concrete and strengthening of monolithic structures is also carried out using dry compounds. A high level of frost resistance and strength allows the use of dry mixes for the repair of products exposed to the negative effects of natural phenomena and cyclic loads. Due to the good characteristics and moisture resistance of the hardened substance, concrete is often waterproofed with it. The material is completely non-toxic, so it is used, for example, to repair drinking water tanks.

Dry formulations are used:

• for the restoration of load-bearing surfaces, floors, stairs;
• for the restoration of roads;
• to protect concrete from corrosion.

The listed species are presented on the domestic market in a wide range. The cost depends on their quality, characteristics and manufacturer.

Overview of popular manufacturers

The requirements for casting and dry mixtures are as follows:

• high degree of adhesion with the restored surface (concrete, stone, rebar);
• exclusion of shrinkage.

Often the main aspect influencing the choice of the buyer is the price of the product. Especially if you need to purchase a large batch for concrete repair.

A brief overview of popular brands will help you make the right decision.

Emaco

The Russian company Basf manufactures and sells Emako compositions used to repair concrete damage of varying degrees of complexity: from small cracks to complex deformations.

• "Emako" N 5100 is used for the first degree of damage: the presence of dirt, cracks, shells.
• With the help of "Emaco" N 900, N 5200 damage of the second degree is repaired: crumbled or peeled off areas of the surface, as well as small chips.
• Emaco S 488 PG, S 488, S 5400 perfectly cope with rust and cracks up to 0.2 mm and a depth of not more than 40 mm (third degree).
• Cracks larger than 0.2 mm, bare reinforcement, a high level of carbonization - the fourth degree, depth up to 100 mm - are restored with Emako T1100 TIX, S 466, S560FR compositions.
• Heavily damaged concrete structures with bare reinforcement and chips more than 200 mm deep are restored using non-shrink (Emaco A 640) and anti-corrosion (Emaco Nanocrete AP) mixtures.

You can buy "Basf" on the official website of the company. The cost varies from 850 to 1700 rubles per package of 25 kg, depending on the components of the composition.

"Birss"

The mixture for the restoration of concrete bases "Birss" is produced in Russia and is designed to perform repairs of any degree of complexity.

• Birss 28, 29, 30, 30N - simple repair of cracks and flaky surfaces.
• Birss 30 C1, 58 C1, 59 C2 (restoring) are used in the second degree of deterioration of concrete.
• In the third degree of damage, the compositions "Birss" 59C3, 59 C are used.
• To correct larger defects, the following mixtures of "Birss" are used: Betonspachtel, RBM or 600 VRS (non-shrinking).
• With the help of "Birss RSM" complex destruction of concrete structures is restored.

The frost resistance of Birss compositions allows repairs to be carried out at low temperatures. They have high adhesive strength, elasticity, density and water resistance.

The advantage of the material is the affordable cost: from 400 to 450 rubles per 50 kg.

Another representative of domestic production is the Bars Consolit repair mixture, which is excellent for the restoration of vertical and horizontal structures. Bars quickly gains the required strength and does not shrink. The mixture has a high level of adhesion to concrete.

There are bulk and thixotropic compositions. The former differ in the thickness of the applied layer, the angle of inclination of the surface to be repaired, and the cost. The price of bulk mixtures varies from 800 to 1,000 rubles per 30 kg.

Thixotropic solutions "Consolite Bars" are:

• reinforcing (113 V60);
• finishing (115 V50);
• repair non-shrink (111 V30).

A moisture-resistant coating is created with a mixture of "Consolit Bars 100", which has an expansion function.

The price varies from 900 to 1,500 rubles per 30 kg, depending on the components of the composition and the region of sale.

Ceresit CX5

Repair of concrete structures in conditions of high humidity is best carried out using a mixture of "Ceresit" ("Ceresit CX5"), which, when solidified, does not shrink and forms a moisture-resistant and frost-resistant coating that reliably covers all defects.

It costs "Ceresit", which has high technical characteristics, quite expensive - about 2,700 rubles per 25 kg.

"Knauf"

Concrete waterproofing is usually carried out with the Knauf Flahendicht mixture, which, in addition to leveling the surface, gives it moisture resistance and vapor permeability. The advantage of the composition is the absence of toxic additives and convenient packaging of 5-6 kg. The Knauf solution can be used both outside and inside the premises. Price - from 350 rubles per 5 kg.

"Found"

A novelty on the Russian market - "Founding Innoline NC60" from "INDASTRO". This is a grouting compound used to repair vertical and horizontal surfaces. The mixture is used not only for restoration work, but also for the installation of equipment on a concrete base. The mixture costs about 800 rubles for 25 kg.

With the help of the dry leveler "Osnovit Selform T-112" they repair floors and walls made of concrete of various types. It has a high level of adhesion and water-repellent properties. It costs from 160 rubles for 20 kg.

"Alit"

The composition of dry mixtures "Alit" (SDR-UR, SDR-U, SDR-UM) includes fine quartz sand, hydraulic binders and non-toxic polymer additives. The composition evens out large cracks and chips, with a depth of 2 to 20 mm, formed on concrete bases, load-bearing structures, stairs.

Possessing resistance to negative temperatures, "Alit" allows you to carry out repairs in the winter.

The price of the mixture is from 1,100 rubles per 25 kg.

mapei
Quick and convenient concrete repair is guaranteed by Mapei dry mix manufacturers. Solutions do not shrink during solidification, do not crack, exclude cavitation, erosion and abrasion. Repair compositions "Mapei" are presented on the Russian market in a large assortment:

High-strength material is used for floor restoration in industrial workshops, repair of airfield slabs, roads, canals and tunnels.

The cost of mixtures depends on the components included in the composition, and varies from 850 to 1,300 rubles per 25 kg.

SW

"SW" is a dry mix used for the repair of reinforced concrete products. The advantages of "SW" are resistance to adverse external factors: mechanical and dynamic loads, high and low temperatures. Moisture-resistant and durable composition is suitable for repair work as soon as possible. The solution, when solidified, forms an anti-corrosion protective coating and is an excellent waterproofing agent.

The price for 25 kg is from 240 to 260 rubles.

How to choose the right repair material

In order to choose the right mixture for concrete repair, it is necessary to follow a certain algorithm of actions.

• Determine the parameters of the repaired area: type of surface, amount of damage, load during operation.
• Choose the type of mixture: cast or dry.
• Select the type of mortar (good adhesion, fiber reinforced).
• Compare prices, mix components and choose a manufacturer.
• Calculate the amount of material needed to complete the work.

Before ordering and buying a mixture, you need to pay attention to the following characteristics:

• hardening time;
• mixture consumption per 1 m2;
• protective functions of the solution;
• shrinkage (you should choose non-shrink compositions).

The market offers a huge number of different repair compounds for the restoration of concrete structures that have lost their original characteristics. They differ from each other in composition, functionality, consumption, price, quantity in the package.

The right choice of repair mix guarantees many more years of safe service for concrete structures.

The cost of concrete repair mixes

Approximate prices for restoration compositions are shown in the table below.