Means for repair of concrete surfaces. Repair mixes for concrete surfaces. Equipment and accessories for repair work

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.

Back to index

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.

Back to index

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 compositions 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.

Back to index

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 one of the most widely used building materials. It is distinguished by outstanding strength, durability as well as reliability. But no matter how high-quality this material is, over time it may require restoration. To do this, special repair mixtures for concrete are used, with which you can remove cracks and close gaps.

Some of the most common problems with concrete structures include:

• dusting;
• level differences resulting from shrinkage;
• traces of mechanical damage.

If the surface layer began to collapse, then it may begin to dust. This also occurs when the filling technology is violated. In addition, intensive operation and loads lead to such consequences. But when exposed to strong loads on a small area, cracks occur. They can also occur with temperature deformations. Sometimes concrete cracks during shrinkage.

Concrete repair mortar can help repair potholes, chips, and holes. Such compositions can be classified according to several criteria, each type of material has characteristic application features and properties, which will be discussed below.

Overview of concrete repair compounds

Today, a variety of mixtures are used for repair work. They are on sale in a wide range. They can be divided into two large groups. Materials have their own characteristics and properties. For example, bulk mixtures have increased fluidity, so their particles penetrate deep into the concrete and are bonded to the base. Such compositions are used to restore defects on horizontal surfaces, namely:

• ceilings;
• screeds;
• floors.

The second group is thixotropic mixtures, which are represented by dry compositions; when mixed with water, they acquire plasticity, do not shrink or delaminate. The materials are highly viscous and do not flow out of the damaged area. Such mixtures are used to seal horizontal cracks and to repair walls. If the master has certain skills, then thixotropic mixtures can be used to eliminate defects in ceilings.

They are based on non-shrinking cement and polymers, namely polyurethane and epoxy resin. Products in this category are characterized by curing in a short time, as they are used for express restoration, when there is no time to wait for curing. An additional advantage is the presence of fiber, which consists of polymer or steel fibers. When the composition hardens, the fiber strengthens the edges of the base, increasing its strength. However, the price of such funds is somewhat higher.

Application features: preparation of the base

Before you apply a concrete repair mortar, you need to prepare the surface by cleaning the damaged area and estimating the approximate amount of material that will be needed. Fragments of concrete, debris and dust should be removed from the crack. For small defects, a stiff brush is suitable, while large damage is cleaned with a water jet or sandblaster.

To fix the edges, the crack is deepened 50 mm below the fracture edge. For stitching, diamond wheels are used, with which you can get smooth edges and get rid of weakly held areas. On longitudinal cracks, it is recommended to cut transverse channels, the distance between which will be approximately 20 cm.

Particular attention should be paid to the reinforcing cage before applying the repair mix for concrete. Metal parts that are outside the concrete coating should be cleaned to a shine. An anti-corrosion primer is applied to the cleaned rods, which will prevent the material from oxidizing during the hydration of the repair mixture. If the defect is more than 50 mm deep, then additional reinforcement is laid in it. The fittings should be located in such a way that the metal is covered with a layer of solution. After performing these works, the area is dedusted, the surface is moistened, and the accumulation of large drops should not be allowed.

Instructions for preparing and applying the mixture

Repair mix for concrete is prepared independently. Fluid and thixotropic mixtures require a small volume of mixing liquid. For 1 kg of dry composition, approximately 250 liters of water will be consumed. Cool water must be poured into a container or concrete mixer. After that, the dry component is poured there, the material is mixed.

Manual processing does not allow to achieve uniformity of the product, so it is better to use an electric mixer to mix the non-shrinking concrete repair mortar. For small volumes, you can use a drill with a nozzle. Further actions depend on what material will be used.

According to the injection technology, formwork must be installed around the perimeter of the site. Its height should be approximately 50 mm. The fluid mixture is poured onto the concrete, distributed to prevent the capture of air bubbles. Sealing the compound is generally not required. To eliminate air pockets at the junction of the formwork and the surface, it is necessary to draw a metal strip around the perimeter.

If you plan to use a thixotropic agent in your work, then you need to collect a certain amount of composition on a grater or spatula. It is pressed into the crack with some effort. In one pass, it is necessary to fill the crack by 15 mm. For the polymerization of the layer, you need to wait some time. Processing is repeated until the defect is eliminated.

Work methodology

The surface is smoothed with a steel trowel. It must first be moistened. It is important to try to mask all the bumps and protrusions. Alignment using the same tool is carried out again, but only after the mixture has set. This will happen in about half an hour.

Sealing cracks in concrete provides for measures aimed at preventing cracking of the composition. To do this, it is kept wet for 24 hours. If the work was carried out in the heat, then these conditions should be provided for up to 3 days. To do this, the restored area is sprayed with water from a spray bottle or watered from a hose, then the base is covered with burlap or polyethylene. It is important to exclude drafts during the drying period. You also need to take care that there are no sudden changes in temperature in the room.

Characteristics of the mixture Ceresit CN 83

If you still do not know which composition to choose, then you can consider the repair mix for concrete "Cerezit". The composition is intended for urgent elimination of defects, it is laid with a thickness ranging from 5 to 35 mm. The consistency of the material is viscous-plastic. The mixture is durable. It can be used uncoated. It is frost and water resistant. It is characterized by high strength and resistance to mechanical stress.

This composition can also be used on vertical bases. It is suitable not only for indoor, but also for outdoor work. The material is environmentally friendly. The substrate must be checked for strength before application. This parameter should be 25 MPa. Application can be carried out on cement-sand screeds, the age of which exceeds 28 days. As for concrete, it can be repaired 3 months after pouring. Its humidity can be 4% or less.

What else you need to know

The density of the dry mix is ​​1.65 kg/dm 3 . The ripening time is 5 minutes. For 25 kg of dry composition, about 3 liters of water will be needed. The mixture must be consumed within 5 minutes. The temperature of the base can be equal to the limit from 5 to 30 °C. Possibility of technological movement - in 6 hours.

Application features

To mix the above composition, water is used, the temperature of which can be from 15 to 20 ° C. The dry mixture is gradually added to the water, mixed. For this, a low-speed mixer or a drill with a nozzle designed for viscous substances should be used.

If you decide to repair concrete slabs using the Ceresit mixture, then it is important to remember that when mixing, you should not be zealous with the volume of water, as its overdose will cause a decrease in mechanical strength and wear resistance. Ultimately, the solution will simply crack. It must be laid on a wet contact layer. Alignment is carried out by a rail-rule, you can use a trowel.

For reference

When laying screeds, a vibrating rail or a vibrating mechanism should be used. The final smoothing and leveling is carried out using plastic or metal floats. If they are being repaired with some interruption, then in between the tools should be washed with water, because the hardened solution can only be removed mechanically.

Characteristics of the mixture "MBR"

Repair mix for concrete "MBR" is a dry composition, which has a gray color. Portland cement is used as a binder. The filler is sand. Its fraction does not exceed 1 mm. The water holding capacity is 98%. In one pass, you can apply a composition with a thickness of 50 mm. Repair of concrete can be carried out after mixing the mixture. To do this, you need 0.2 liters of water per 1 kg of dry composition. The usage time is 60 minutes. Hardening should be expected in a day.

Characteristics of the mixture Emaco

One of the leading manufacturers of the market is the repair mix for concrete "Emako". S88C is one of the varieties that is ready to use. The maximum filler fraction is 2.5 mm. The material is not prone to delamination, has high adhesion to steel and concrete surfaces. This non-shrinking mixture retains its properties in a plastic and hardened form.

EMACO 90 is a mixture that has sand, cement and polymers among its ingredients. The maximum fraction of the filler is 0.5 mm. After addition, a thixotropic solution is obtained, which is durable and resistant to negative environmental influences.

Potholes, chips, cracks - all this can happen to any concrete surface. In this article we will tell you how and with what mixtures you can repair concrete.

Types of repair compounds

Concrete is known for its strength, reliability and durability. However, under the influence of various factors over time, it begins to collapse. The reason for this may be poor-quality installation, non-compliance with the proportions of the components, aggressive external environment, mechanical damage. Defects can be eliminated with the help of special repair compounds.

In order to prepare the composition, you need to mix the dry repair mixture with water. A variant is possible with the use of special additives that improve some of the characteristics of concrete. Ready-made compounds are used to repair floors, walls, stairs, bridges, roads and other concrete structures.

All repair mixtures can be conditionally divided according to their purpose:

• for the repair of load-bearing concrete structures, for example, columns, beams, floor slabs;
• for the repair of roads and concrete floors;
• to protect concrete structures from corrosion.

A fairly wide range of repair compounds with different properties is presented on the market, from various domestic and global manufacturers. Accordingly, their quality and price category can vary quite significantly.

Repair compounds must provide high adhesion to concrete, non-shrinkage and absolute compatibility with it. With their help, the bearing capacity of structures is restored, water resistance, frost resistance and concrete strength are increased. In addition, they must be affordable and economically viable.

According to international and domestic experience, it has been proven that the use of repair mixtures is more effective than the use of traditional cement-sand mortars.

Repair mixes for concrete are divided into thixotropic and casting mixes. The former are used for vertical surfaces, the latter for horizontal ones. You can increase the reinforcing properties with the help of fiberglass.

How to choose a repair compound

Several factors influence the choice of repair composition:

• damage type
• defect size
• terms of Use

There are three main types of repairs:

• reinforcement of the concrete surface
• leveling the concrete surface
• crack repair

To strengthen concrete, which carries heavy loads and has a fragile surface (screed, floor slabs), deep penetration primers are usually used.

The most common type of concrete repair is leveling unevenness. The sealing of vertical surfaces is carried out using thixotropic dry mixes. They perfectly cling to the surface, hold well on them and do not blur. They have minimal shrinkage and high characteristics in terms of strength, water and frost resistance.

Particularly critical areas require the addition of reinforced fiberglass. Quick repair is provided by special compounds. Their curing time is up to 6 hours. But they have a limitation on the thickness of the layer - up to 30-40 mm.

Horizontal surfaces are leveled with casting mixtures. They are more liquid and, due to this, they are simply poured onto the surface. The mixture sets quickly, has minimal shrinkage and is quite strong. One layer can be laid up to 10 cm thick.

Leveling compounds are also used to repair cracks in concrete.

The choice of repair composition is influenced by the operating conditions of the structure. If necessary, components can be added to the mixture that enhance various properties, for example, water resistance or quick solidification.

The most famous manufacturers of repair mixtures are BASF, MAPEI, SIKA, from Russian ones - Lakhta, Alit, Konsolit, SpetsRemSmes.

floor leveling

To level the floor, it is necessary to prepare a cement-sand screed. The concrete surface is pre-cleaned of dust and treated with a primer. After that, they are determined with the point at which the floor will be leveled, beacons are installed at the laser level.

Next, the screed is poured. Its maximum height should not exceed 35-40 mm. The pre-mixed solution is poured onto the surface and leveled with a spatula. On the second day, the beacons are removed and the seams are sealed with a rubbing solution.

The screed should dry well. This may take up to 2 weeks. The screed is covered with a film, and the surface itself is periodically moistened with water. Thanks to this, it will become stronger and will not crack.

Horizontal surfaces can be repaired using a self-levelling compound. They are used in the presence of small defects and uneven areas. The end result is a perfectly flat surface.

To level the floor, I use the following mixtures: VOLMA-Nivelir Express (cost - 14 rubles / kg), Vetonit-2000 (17 rubles / kg), KESTONIT 97 (39 rubles / kg).

Floor pothole repair

At the beginning of work, small incisions are made around the damage using a diamond disc or grinder. Then, the remains of damaged concrete are removed with a chisel and a perforator, the surface is cleaned of dust. For better adhesion of the composition to concrete, a special epoxy primer is applied to the surface.

After applying the solution, it is necessary to remove its excess and level the surface with a rail. After complete drying, the composition becomes as durable as possible. The closed place is polished.

The following mixtures are suitable for filling potholes: IVSIL EXPRESS-BASIS (cost - 10 rubles / kg), Thomsit RS 88 (30 rubles / kg), LAKHTA Quick Repair (80 rubles / kg).

Crack repair

Cracks appear in concrete due to various reasons. Over time, they can grow, destroying the whole structure. This defect must be repaired.

Vertical cracks are repaired by the injection method. When using the injection method, the composition is pumped into the fracture using special equipment - a packer.

Surface cracks, which usually form on inclined and horizontal surfaces, are repaired by the saturation method. In this case, the cracks are impregnated with a mixture without pressure.

There is another way to fix cracks. At the beginning of the work, the crack is sawn 25-50 mm deep and 10-20 mm wide. Excess concrete must be removed and the crack blown out of dust and dirt. The cut is filled with a repair mixture. In the event that the concrete crumbles, it is worth using a better mixture, if it practically does not dust, a cheaper agent will do.

The following mixtures can be used to repair cracks: LAKHTA basic repair compound (cost - 57 rubles / kg), BASF MasterEmaco S 488 (33 rubles / kg), Sika Monotop 612 (86 rubles / kg).

Comparative table of technical characteristics of dry repair mortars:

The main technical characteristics presented in this table will help you choose the best repair mortar for your needs.

The right mixture for concrete repair and the quality of the work performed guarantee an excellent end result.

Andrey Badovsky, rmnt.ru

It is generally accepted that concrete is characterized by reliability, strength and durability, however, under the influence of various factors, it can get damaged and begin to collapse. If violations of the structure have not yet led to serious consequences, they can be eliminated with the help of a repair mixture for concrete. Such compositions are components specially selected in strictly defined proportions, after preparation (mixing) they become suspensions, solutions or other viscous masses used to repair, protect, enhance reinforcing properties and waterproof damaged areas.

The main task preceding the start of restoration work is the definition of technology and the correct selection of components. Repair dry mix for concrete is indispensable in the elimination of minor damage to various structures in cases where it is possible to avoid the costs associated with the overhaul. Such compositions, thanks to various fillers and additives, are well suited for restoring the surface structure of reinforced concrete and concrete structures.

The widest range of these products with different properties is currently available from different manufacturers in many countries, so the price of a concrete repair mix can vary greatly. Some brands of restorative compounds can be interchanged, others are only suitable for a certain type of work.

All repair mixtures can be divided into two main categories. Cast (or bulk), used for horizontal surfaces, and thixotropic - for vertical ones. For example, repair mixtures MBR-300 and MBR-500 for concrete, produced by CJSC Quarry "Mountain Khrustalnaya", the differences in marking show that the first is of the bulk type, the second is of the thixotropic type.

The choice of composition is made depending on the nature of the damage, the type of surface, and operating conditions.

One of the most common flaws in concrete structures is unevenness. For vertical surfaces, in this case, thixotropic dry compositions are used that do not blur, fit well and hold well, have minimal shrinkage, high strength, water resistance and frost resistance. It is recommended to use deep-penetrating, adhesion-improving primers prior to their application.

Concrete structures that experience significant loads may have an insufficiently strong surface (screeds, floor slabs and other monolithic structures). Deep penetration primers are also well suited for strengthening them. During the examination, bare reinforcement can be detected, an anti-corrosion primer is used to eliminate the defect.

Particularly critical areas are restored using special mixtures for quick repair, which include fiberglass to improve the reinforcing characteristics.

Horizontal planes that have received damage and require alignment are restored by using casting mixtures. Possessing a relatively liquid consistency, they are poured onto the surface with a layer of up to 100 mm, quickly set, give minimal shrinkage and high strength.

In climatic conditions, where there are frequent temperature changes, one of the most common defects in concrete structures are cracks. Their repair in most cases is carried out using the same compositions as when leveling surfaces, only using a different technology.

We make the composition ourselves

Even the strongest and most durable structures sometimes need some attention and timely repairs. If the area of ​​damage is relatively small, you can not buy factory mixes, but make repair compounds for concrete with your own hands.

Most often in the household, restoration of the screed is required. In this case, to repair a small damaged area, you can make a mixture of the following components:

• portland cement - 6 kg;
• quartz sand (fractions up to 1.0 mm) - 8.6 kg;
• fine gravel (2.0 ÷ 5.0 mm) - 9.0 kg;
• ground limestone - 0.8 kg;
• polypropylene fiber - up to 4 gr;
• a complex of modifying additives, the composition of which depends on the characteristics of the old concrete and operating conditions, these can be regulators of: rheological properties; setting and hardening processes; special purpose (frost resistance, moisture resistance, heat resistance); polyfunctional action;
• water - 2 l.

The dosage of modifying additives is indicated on the package and usually does not exceed 0.5÷0.8% by weight of cement.

Selected and weighed components are thoroughly mixed in dry form. The required amount of clean fresh water is poured into an empty container, after which a loose composition is added to it with constant stirring. In order to form a homogeneous mass, it is best to use an electric drill with a mixer nozzle. The finished mixture should be used within one hour.

Price

You can buy a fine-grained mixture for concrete repair in almost any corner of Russia. In most cases, delivery of goods directly to the customer is offered as an additional service. The table shows approximate prices in Moscow for various dry repair mixes.

Concrete is considered a very strong, reliable and durable material. However, under the influence of various influences, it begins to collapse. Sometimes defects occur after a short time, and they can be eliminated with special repair compounds.

Concrete is strong enough, strong and durable material, however, it is not eternal. Cracks and breaks may appear on it. And in such cases, it is necessary to use special mixtures to repair it.

Repair compositions for concrete are special products, which include cements, fillers, sand and various additives that give certain properties to the solution.

Scheme of repair of concrete defects with reinforcement exposure: a - concrete defect with reinforcement exposure; b - removal of destroyed concrete, application of a protective layer on the reinforcement; c - restored section of the structure 1 - building structure; 2 - fittings; 3 – “KTtron-primer” material; 4 - repair material "KTtron" thixotropic (depending on the project).

Dry repair compounds are completely ready for use after mixing with water. They are used to eliminate imperfections in concrete floors, walls, bridges, stairs, roads and other concrete structures.

Dry repair compounds are intended for:

• repair of load-bearing structures (beams, columns, floor slabs, etc.);
• repair of road surfaces (runways, parking lots, etc.), industrial floors, floors in warehouses, etc.;
• protection of concrete and reinforced concrete surfaces against corrosion.

Currently, repair compounds for concrete are presented in the widest range: from various manufacturers, with different properties and different price categories. Means for removing defects are divided into two main groups: thixotropic (for vertical surfaces) and casting (for horizontal planes). To increase the reinforcing properties, fiber can be added to the composition of the mixture.

The choice of mix for concrete repair

Scheme for repairing a panel made of cellular concrete with a destruction depth of 20 to 50 mm and an area of ​​up to 0.5 m2: 1 - panel; 2 - nails; 3 - metal wire; 4 - contour of destruction.

The choice of mixtures for concrete repair depends on several parameters: on the type of damage, surface defect, as well as on operating conditions.

Strengthening the concrete surface. Often, concrete surfaces that carry heavy loads have a fragile surface (floor slabs, screed and other monolithic structures). In such cases, deep penetration primers for concrete should be used.

Surface leveling. Rough surfaces are one of the most common defects in concrete structures. In this case, deep penetrating primers are also excellent. For vertical surfaces, thixotropic dry mixes should be used, they fit well on the surface, do not blur and adhere well to vertical planes. In addition, they have high strength, frost and water resistance and have minimal shrinkage.

When repairing particularly critical areas, it is necessary to use reinforced fiberglass. There are also special compositions for quick repairs, which harden in the shortest possible time. In this case, the thickness of each layer should not exceed 35 mm.

Bare reinforcement in concrete structures must be treated with an anti-corrosion primer.

For leveling horizontal surfaces, casting dry mixes are used. Such compounds have a more liquid consistency, unlike thixotropic ones, and are poured onto the surface. The thickness of one layer can reach 10 cm. The mixture has minimal shrinkage, high coating strength and fast setting.

Crack repair. Another common concrete surface defect is cracks. To repair cracks, as a rule, the same compositions are used as for leveling the surface.

When choosing a composition for concrete repair, it is worth considering the operating conditions. During production, various components can be added to the mixture, giving certain properties, for example, frost resistance, water resistance, rapid solidification of the composition, and so on.

floor leveling technology

The use of non-shrink fast-hardening cement-based compounds.

Alignment of horizontal surfaces can be done independently. Although the work is quite laborious and requires knowledge of technology, but, following all the rules, you can get a perfectly flat plane with your own hands.

To level the floor, a cement-sand screed is required. Before starting work, the surface must be cleaned of dirt and dust, the old coating. Then the plane is treated with a primer, which contributes to a more uniform spreading of the solution.

Next, you should determine the highest point, according to which the floor will be leveled. After that, beacons are installed, which can be used as metal corners, profiles or pipes. Beacons are installed in such a way that their height is at the same level. To do this, it is better to use a laser level.

Schemes of sealing expansion joints of concrete dams: a - diaphragms made of metal, rubber and plastics; b - dowels and gaskets made of asphalt materials; c - injection seals; g - bars and slabs of concrete and reinforced concrete; 1 - metal sheets; 2 - profiled rubber; 3 - asphalt mastic; 4 - reinforced concrete slab; 5 - wells for grouting; 6 – grouting valves; 7 - reinforced concrete beam; 8 - asphalt waterproofing pad.

After installing the beacons, the pouring of the screed begins. The layer thickness should not exceed 40 mm. The solution, previously mixed in a plastic or metal container, is poured onto the base, then leveled with a spatula.

After pouring, the screed must dry out, this may take up to two weeks. On the second day after pouring, it is necessary to remove the beacons, and seal the seams with a grouting solution.

When drying, the screed must be covered with plastic wrap. Periodically, it is recommended to moisten the surface with water. This will prevent cracking of the surface and give the screed greater strength.

It is also possible to repair horizontal concrete surfaces with the help of a self-leveling mixture. Such compounds are used in cases where the surface has small defects, uneven areas up to 3 mm. The result is a perfectly flat surface.

Pothole Removal

Scheme of repairing a chipped edge of a concrete coating at the seam: a - before repair; b - after repair; 1 - existing concrete; 2 - edge chip and crack in concrete; 3 - crushed stone; 4 - dirt; 5 - expansion joint; 6 - waterproofing; 7 - freshly laid concrete; 8 - polyethylene film; 9 - mortgage board.

Often, defects such as potholes appear on the concrete surface. They are eliminated as follows. First, an incision is made along the perimeter of the damage, the depth of which should not exceed 2 cm. For this, it is better to use a tool such as a grinder with a diamond disc. After the incision is made, the remains of the concrete are removed using a perforator and a chisel.

Next, remove dust and dirt. For the best removal of all debris, a vacuum cleaner or sandblasting equipment should be used. An epoxy primer is applied to the cleaned surface. It provides better adhesion of the composition to the concrete surface. Then the pothole is filled with a special compound for repairing the concrete surface.

Excess mortar is removed, and the surface is leveled with a rule or rail. After that, the patch is kept for the required time until it dries completely. During this time, the composition acquires its maximum strength. The final stage is grinding the repaired damage.

For repairs, special dry mixes should be used, and not a regular concrete mortar, since the repair compounds have special properties that ensure the strength of the coating.

Repair of cracks in concrete

Seam repair.

Cracks in concrete can appear for a variety of reasons. At the same time, they can develop further, which negatively affects the strength of the whole structure, or not spread further. In any case, the defect must be repaired.

Depending on the width of the crack and the material used to seal the crack, there are various ways to eliminate defects:

• injection. Vertical cracks are always eliminated in this way. For injection, special equipment is used - an injection packer, with the help of which, under pressure, the crack is filled with a repair compound;
• saturation. The method of saturation (impregnation) is used to eliminate surface cracks. As a rule, such defects occur on horizontal or inclined surfaces. When impregnating cracks, the repair compound is injected into the crack without pressure.

Cracks can be eliminated in the following way. First, the crack is sawn to a depth of approximately 20-50 mm (depending on the size of the crack) and a width of 10-20 mm. After that, excess concrete is removed, dust and dirt are blown out. Then the cleaned cut is filled with a repair compound. At the same time, it is worth considering that if the concrete does not particularly dust during operation, then the composition can be used cheaper, simpler. If the concrete crumbles, then you should choose a better and more expensive product.