Using mixtures for concrete repair. Selection of materials and main stages of concrete repair work Manufacturers of repair mixtures

It is generally accepted that concrete is characterized by reliability, strength and durability, but under the influence of various factors it can become damaged and begin to collapse. If structural damage has not yet led to serious consequences, they can be eliminated using a concrete repair mixture. Such compositions are specially selected components in strictly defined proportions; after preparation (mixing), they become suspensions, solutions or other viscous masses used for repair, protection, enhancement of reinforcing properties and waterproofing of damaged areas.

The main task preceding the start of restoration work is to determine the technology and correct selection components. Repair dry mix for concrete is indispensable when eliminating minor damage various designs in cases where the costs associated with major repairs can be avoided. Such compositions, thanks to various fillers and additives, are well suited for restoring the surface structure of reinforced concrete and concrete structures.

Currently available the widest range these products having different properties, produced by different manufacturers in many countries, so the price of concrete repair mixture can vary greatly. Some brands of restorative compounds can be interchangeable, others are suitable only for a certain type of work.

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

The choice of composition is made depending on the nature of the damage, 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 compounds are used, which do not spread, adhere well and hold well, have minimal shrinkage, high strength, water resistance and frost resistance. Before applying them, it is recommended to use deep-penetrating, adhesion-improving primers.

Concrete structures experiencing significant loads may have an insufficiently strong surface (screeds, floor slabs and other monolithic structures). Primers are also good for strengthening them. deep penetration. During the inspection, exposed reinforcement may be identified; an anti-corrosion primer is used to eliminate the defect.

Particularly critical areas are restored using special mixtures for quick repair, which contain fiber to improve reinforcing characteristics.

Horizontal planes that are damaged and require leveling are restored by using casting mixtures. Having a relatively liquid consistency, they are poured onto the surface in a layer of up to 100 mm, set quickly, provide minimal shrinkage and high strength.

IN climatic conditions Where there are frequent temperature changes, one of the most common defects in concrete structures is cracks. In most cases, their repair is carried out using the same compounds 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 avoid buying factory-made mixtures and make repair compounds for concrete yourself.

Most often in the household, screed restoration 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 g;
a complex of modifying additives, the composition of which depends on the characteristics of old concrete and operating conditions, these can be regulators of: rheological properties; setting and hardening processes; special purpose (frost resistance, moisture resistance, heat resistance); multifunctional action;
water – 2 l.

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

The selected and weighed components are thoroughly mixed in dry form. Pours into an empty container required quantity clean fresh water, after which the bulk 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 attachment. 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 indicative prices in Moscow for various dry repair mixtures.

Supplier	Name	Packaging, kg	Price, rubles	Notes
"Stroymag" (i/m)				order delivery by phone or pick up


"Stroyportal" (i/m)	Mapegrout Thixotropic			cash/non-cash
"Vipkraska" (i/m)				sales and delivery
"Blizko.ru" (i/m)	Emaco Fast Fluid			Moscow and region
OOO Trading house"Quartz"	MBR-300 ÷ MBR-700
"Maximus-Stroy" (i/m)				call delivery; retail prices, volume discount system


	TM-40-Penetrating

The choice must be approached as responsibly as possible. After all, if work to restore a concrete base is carried out using unsuitable or low-quality materials, the structure only loses strength, not to mention the fact that its cost increases significantly.

What causes concrete to fail?

Concrete structures are destroyed under the influence of the following negative factors:

Chemical reactions caused by increased carbon content in concrete. These processes provoke a violation of the proportions of water and cement content in the solution.

Chemical reactions caused by the action of chlorine ions contained in road salt, which is used in the cold season to protect reinforced concrete road surfaces from ice. As a result of these processes, oxidation of reinforcement in concrete begins.

Action of moisture. Water seeps into concrete cavities. When frozen, it crystallizes and causes destruction and cracking in the concrete structure.

Mechanical factors - shocks and dynamic impacts exceeding the permissible loads provided for in the design documentation, etc.

Seismic processes.

Natural disasters - floods, hurricanes, etc.

Fires.

Failure to comply with technological standards and violations at the construction stage. For example, long periods of downtime during the concreting stage can lead to poor adhesion of the new concrete to the old base. This entails the formation of working (cold) seams and, over time, reduces strength and damages the aesthetics of the structure.

The main stages of concrete repair activities

Work is carried out in the following sequence:

Examination. At this stage, specialists assess the severity of the damage caused and analyze possible reasons who provoked them. To do this, the size of cracks, the thickness of the protective layer, the intensity of carbonization processes, etc. are measured. Based on the results of the surveys and their recommendations, a repair plan is drawn up and the means intended for this are selected.

Preparatory work. The damaged layer and signs of previously carried out restoration measures are completely removed from the base to a dense, clean and solid base. Its surface is cleaned of all types of dirt, traces of paint, oils, etc.

Processing of reinforcement. Bare reinforcement bars are carefully cleaned from traces of corrosion and covered with protective compounds.

Repair work. Construction mixtures for concrete repair are applied manually, by pouring (for example, into formwork) or by spraying/gunning.

- Recovery by using special means. Protective compounds on an organic or inorganic basis protect concrete from the negative effects of the environment, pollution and other aggressive external factors.

If necessary, a decorative layer is applied over the protective layer.

Types of mixtures for concrete repair

Depending on the purpose and nature of use, the following types of compositions are distinguished:

Compositions used to restore load-bearing concrete structures (floors, beams, highways, floors in industrial premises and other types of coatings experiencing strong dynamic loads).

Compounds used for non-structural restoration of concrete, leveling the surface of the base and sealing minor defects.

When choosing repair staff for concrete, the nature and degree of damage, specific operating conditions, technical parameters of concrete and other factors are taken into account.

Concrete repair mixtures from MAPEI

MAPEI offers various materials for a complete and quality repairs reinforced concrete structures:

Means for anti-corrosion protection of fittings.
Materials for repair of reinforced and unreinforced concrete.
Leveling mixtures.
Waterproofing compounds.
Epoxy resins for crack repair injection method.
Finishing decorative and protective materials, etc.

The most popular materials for complex concrete repair from MAPEI are produced in Russia, at the company’s own factories.

The most popular mixtures for concrete repair from MAPEI

Mapegrout Thixotropic is a dry mixture for the repair of reinforced concrete and concrete structures, reinforced with polymer fiber, with compensated shrinkage. It is characterized by excellent adhesion to concrete and steel, frost resistance, water resistance, and mechanical strength. Applied in a layer of 10 to 35 mm. Thanks to its thixotropic properties, it is suitable for use on both vertical and horizontal bases, without requiring the use of stationary formwork. Gains strength quickly. This dry mixture is intended for surface restoration concrete foundations- for example, for filling formwork marks, smoothing open reinforcing rods, repairing upper layers industrial floors, ramps, etc.

Mapegrout Hi-Flow is a dry mixture for repairing concrete by pouring into formwork. Indispensable where, due to the depth and specificity of the damage, materials with high fluidity rates are required - for example, for restoring road surfaces, filling the distances between elements of concrete structures, etc. Apply in a layer of 10 to 40 mm. Upon contact with water, it forms a concrete mixture that is not subject to delamination, resistant to abrasion, low temperatures and has waterproofing properties.

Mapegrout 430 is a concrete repair material characterized by controlled shrinkage and medium strength values. Used for repairing concrete foundations destroyed as a result of corrosion processes in reinforcement. It is applied in a layer of 5 to 35 mm without the use of formwork on vertical surfaces. In order to ensure the composition can fully expand on open construction sites, it is recommended to use it in combination with the Mapecure SRA additive.

Mapegrout SV-R Fiber is a dry repair mixture that quickly gains strength and is intended for the repair of serious defects where the coating is subject to heavy loads and long-term downtime is not possible (road surfaces, airport runways, industrial premises etc.). Can be used under negative temperature conditions from -5*C. Apply a layer of 20-50 mm.

ARB-10 and ARB-10F are concrete repair compounds that quickly gain strength. They are characterized by high resistance to mechanical damage, water resistance and compensated shrinkage. Thanks to the presence of steel fibers in the composition, ARB 10F can be used to repair foundations subject to severe loads. These products were developed specifically for the restoration of airport runways, bridges, industrial floors, etc. Apply in layers from 50 to 300 mm

Mapefill and Mapefill 10 are expansive, flowable concrete mixtures that do not shrink and quickly gain strength. Used for base fixation and anchoring of industrial equipment. In addition, it is suitable for filling seams, technological cavities, etc.

Stabilcem is a cement binder for the preparation of injection solutions for repairing cracks in concrete, brick, and stone using the injection method. It is also used to compact foundations and fill hard joints.

Compositions:

Mapelastic is an elastic composition for protection against water load and atmospheric influences, both external (balconies, terraces) and underground parts of the structure (basement walls, swimming pools, water tanks, etc.), as well as plastered surfaces and old floors.

Idrosilex Pronto - rigid waterproofing for the protection of underground structures: basements, foundations, channels, swimming pools, under positive and negative water pressure

We focused only on the most famous repair compounds from MAPEI. The company’s product range is so wide and includes so many materials for different areas of construction that it is simply impossible to list the entire product line in one article.

Comments:

Repairing cracks in concrete sometimes appears as a task of increased importance. Defects and cracks form both in old structures and in newly built ones. Before you start getting rid of cracks, you will need to choose the most convenient method.

Cracks in concrete can occur due to moisture or deformation concrete product, shrinkage or loading.

Sealing cracks in concrete

Defects and cracks can form both in new concrete structures and in those that have been in use 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 or shrinkage. Deformation cracks are those that occur due to temperature expansions or incorrect shrinkage. They can appear in structures with light loads that are not load-bearing. These can be screeds, the bases of paths 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 foundations and soils.

Shrinkage cracks can be caused by the concrete mixture setting and drying too quickly. The opening of cracks may be uneven, but not large. Sometimes concrete becomes covered with a web of small cracks that are barely noticeable to the eye. But if you wet the surface, the 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 a concrete structure:

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

Seating. For example, a foundation made of concrete may settle due to the fact that the soil compresses unevenly, and the load is different for different areas. A material such as concrete is not so strong that it does not change under loads, and during its hardening it can crack due to uneven loads.
Corrosion. The impact of carbon dioxide, carbonation, and salts on the components creates the most favorable environment for cracks to appear in the material.
Mechanical loads. Various types of destruction can occur due to accidents, possible seismic activity, excessive vibrations, and so on.
Other impacts. The material may slowly deteriorate due to the influence of salts, acids or alkalis.

Here are the main reasons why defects may occur in the material. Any problems of this kind require immediate elimination, otherwise cracks in concrete will appear again and again.

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How to repair defects in concrete

When starting to seal cracks, first determine how you will do it. In most cases, thin cracks in concrete are simply primed, plastered or painted over.

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

Sealing of cracks is carried out mainly by filling the depth with synthetic mixtures with the addition of resins, which have low viscosity. Holes are drilled along the crack; they must be placed diagonally, towards the defect. After this, bushings are placed in the holes and the working mixture is pumped through them. Then the resin is pressed in using an injector. This method helps ensure that the structure has good strength and is able to function as a single unit.

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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 possessing best effect. But to use it you must have certain working skills. This method is more expensive, but the results are impressive. The procedure is carried out as follows: into the formed seams, voids, cracks in concrete, pump special compounds from polymers or cement mixtures with additives. 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 tap the space with a chisel. The excess layer of concrete must be removed 300 mm up from the crack and the same amount down. After treatment, crumbs and dust are completely removed from the area and the prepared repair compound is applied. It is prepared from a solution of sand and cement, adding polymer components. You can use epoxy resin in this composition. At the last stage, the treated surface is coated with polyurethane sealant.

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Which repair compounds are more popular?

Preparation of a 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, a new layer of cement-sand mixture will then need to be applied 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 the damage and cracks. For example, the composition for sealing large defects will differ from the one used to treat hairline cracks.

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

When making the mixture, the composition should turn out a little fatter than the previous one. After laying, the concrete mixture 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 cracks small size. The composition is made by mixing Portland cement and sand, ratio 1:3. For the sealer, styrene-butadiene latex can be used. The coating is waterproof and the adhesion of the mixture to the surface is improved. If the cracks are very small, less than 100 mm in depth, it is better to apply the composition using a pneumatic apparatus. This results in a better seal. You can choose shotcrete concrete for embedding - it will provide good strength for possible compression.

Concrete surfaces and structures have the qualities of durability and high strength, however, with prolonged use or significant loads, damage and cracks appear on them. In this case, a concrete repair mixture will help. However, before purchasing it, it is important to consider the features and quality characteristics each brand.

Characteristics of repair mixtures

The mixture intended for the restoration of concrete structures and surfaces must be resistant to frost and temperature changes. Among other things, it must have a high level of adhesion and also demonstrate durability. The composition must have antiseptic properties and vapor permeability. Once applied to the surface, the mixture should cope well with water.

Indications for use of the repair mixture

It is applied when there are a large number of potholes and defects on the base. Such compositions are used when cracks are opened by 0.3 millimeters or more. Quite often, concrete is characterized by increased dust formation, and the use of a repair mixture is also indicated. The structure can become covered with voids, undergo corrosion, and have all sorts of defects. In all these cases, it is recommended to use a repair mixture.

Manufacturers of repair mixtures

Repair mixture for concrete "Emako" is produced in Russia. It is used to restore concrete structures that have serious or minor damage. This composition is capable of eliminating five different degrees of damage.

The first degree involves the presence of shells, shrinkage cracks, and contamination. The maximum depth of damage is 5 millimeters. To eliminate such errors, you should use a mixture of the Emaco N 5100 brand.

The second degree of damage involves peeling of the surface and the presence of minor chips. In order to get rid of such shortcomings, you should use compositions of the Emaco N 900 and Emaco N 5200 brands.

The third degree involves the occurrence of cracks within 1-2 millimeters and rust. The maximum depth of damage is 40 millimeters. If you choose repair mixtures for restoring concrete with such errors, then it would be best to purchase compositions of the Emaco S 488 PG, Emaco S 5400 and Emaco S 488 brands.

The fourth degree is cracks that are larger than 0.2 millimeters. In this case, exposed reinforcement may appear and carbonization may occur. The maximum depth of damage is 10 cm. It is best to purchase Emaco T1100 TIX, Emaco S560FR or Emaco S 466 mixtures to eliminate such damage.

The most recent damage is grade five. In this case, the reinforcement may be exposed, and there may be deep cracks on the surface. The depth of the damage exceeds 20 cm. The Emaco Nanocrete AP mixture will help protect the reinforcement from the effects of corrosion. If you decide to use the above-mentioned brands of repair compounds, then you will have to pay from 13 to 26 dollars per 25 kg.

Repair mixtures of the Birss brand

Repair mixtures for restoring concrete are produced by the Birss company, which is located in Russia. These compositions are intended for the restoration of structures and If there is a need to cope with damage of the first degree, then the mixtures “Birss 28”, “Birss 29” can be used. While the second degree will be handled by the compositions “Birss 30 C1” and “Birss 58 C1”.

This manufacturer has repair mixtures for all degrees of damage. The main advantages include salt resistance, high level of adhesion, water resistance, frost resistance, density and elasticity, as well as wear resistance and shrinkage resistance. The price of such mixtures is much lower and is equal to 6 dollars per 50 kg.

Features of Bars repair mixtures

The Bars concrete repair mixture is easy to apply and can be used to repair horizontal and vertical surfaces. These compounds can even be applied to old concrete surfaces. Mixtures of bulk and thixotropic types are available for sale. The last variety includes the composition of the Bars 102 B45 brand; it should be applied to the surface in a layer whose thickness varies from 2 to 4 cm. The composition contains non-shrinking components, as well as reinforcing fibers. The price compared to other mixtures is considered average and is equal to $13 per 30 kg. If there is a need to eliminate water leaks in a concrete structure, then you should use the Bars 113 console; this mixture has additional strength properties and expansion ability.

Features of Ceresit repair mixtures

Repair mixture for concrete "Ceresit" is widespread on the market building materials, perhaps most of all. It has excellent restoration properties for all kinds of concrete surfaces and bases. After application, the composition forms a non-shrinking plug that is resistant to frost and water. It will reliably seal all cracks and leaks. You can purchase this composition at a higher price compared to other mixtures; the price varies between $41 per 25 kg. However, this mixture will be compensated by superior quality.

Features of MBR repair mixtures

In the assortment you can find other types of compositions. For example, the repair mixture for concrete MBR 500 is intended for repairing structures that have defects. This composition can be stored for six months at a fairly wide temperature range, from -50 to +50 degrees. Considering technical specifications of this composition, it can be noted that it has different brands within the range of MBR 300 - MBR 700. Each of these mixtures can be laid with a maximum thickness in one go. For example, MBR 320 is applied at a thickness of 40 millimeters, while MBR 700 is applied at a thickness of 20 millimeters. As an alternative solution in the latter case, a form can be used. After hardening, MBR 700 acquires a density of 2350 kilograms per cubic meter. While MBR 300 demonstrates a density within 2100 grams per cubic meter.

The repair mixture for concrete should be selected depending on the type of defect, the expected load during operation, and the size of the damage. If there is a need to strengthen the base, then the most suitable option is the use of a deep-penetrating primer mixture. If you are choosing a concrete repair mixture that should help strengthen a vertical surface or concrete structure, you should prefer thixotropic compounds. Such mixtures have a thick consistency and excellent adhesive properties. This means that they adhere quite well to the surface of the walls.

Conclusion

When leveling surfaces, you should use compounds that have good qualities clutch. If there is a need to eliminate cracks, it is recommended to choose fiber-reinforced compounds. Before purchasing, you need to pay attention to some characteristics of the composition, including the hardening period, material consumption, and shrinkage size.

Concrete is a complex composite material with a capillary-porous structure that operates under conditions of 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 backdrop 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 tiny defects, which significantly reduces the strength of the artificial stone and affects further degradation;
destruction of surface layers. This may include the peeling of the protective layer, the formation of voids and cavities on the surface;
formation of destruction, loose areas, cracks in deeper layers ;
corrosion of reinforcement, mortgages.

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

Fighting methods

The choice of concrete repair technology depends on the type of damage detected after structural analysis. When selecting a technical solution, we focus on modern technologies and materials that ensure an extension of the service life of concrete from 15 to 40 years.

When choosing material, rely on the following indicators:

degree of responsibility of the structure, load-bearing capacity, load;
depth of defects;
operating conditions (dynamic loads, aggressive environments, 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 major defects

If significant damage has occurred on the surface, the base is filled with new concrete. Initially, the damaged area is cleaned to sound concrete, then repairs are carried out.

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

Conventional heavy concrete is used when completely or partial renovation structures, pouring solid reinforced concrete jackets, applying repair layers more than 10 cm thick.

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

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

Dry mixes (Emaco, BIRSS, Osnovit, Knauf)

Dry mixtures are prepared on the basis of cement, which ensures 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 per application varies from 5 to 50 mm, which is typical for vertical/horizontal bases, on ceiling surfaces thickness is taken as 30 mm. Maximum effect achieved using primers.

Types of dry mixtures for repairing artificial stone:

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

Scope of application of dry mixtures: accelerated repairs, sealing of defects, including concrete, reinforced concrete structures, road surfaces with concrete pavement, sealing of industrial floors, joints

Advantages:

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

Flaws:

low shelf life;
high price;
Use only at positive temperatures.

Specifications

Frost resistance	F400
Waterproof	W10-W12
Adhesion, MPa	2.85
Compressive strength, MPa	B40

Thixotropic compounds (MAPEI, BASF, Sika)

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

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

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

Advantages:

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

Flaws:

high price;
application at positive temperatures.

Specifications

Thixotropic compounds are suitable for structural and non-structural repairs

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

Such materials are used for various types concrete repair, when injection work ah to protect concrete from various types of influences (polyurethane, acrylate, epoxy). Rigid, semi-rigid, and elastic solutions are used.

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

Repair acrylate compounds are used to seal cracks, chips, and increase the strength and water resistance 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 load-bearing capacity of concrete, create an adhesive layer, and repair cracks. Two- and three-component polyurethane are effective in localizing leaks and blocking the flow of water.

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

Advantages:

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

Flaws:

low viability.

Specifications

Viability	30 minutes
Curing time	24 hours
Adhesion to concrete	Over 1.5 MPa
Consumption	200-300 g/sq.m.

Secondary waterproofing of concrete, repair (SCHOMBURG, Protexil)

To protect structures from operating conditions, the following is used:

hydrophobic impregnations (silane, silaxane, polysilaxane) - essentially, this is the treatment of surfaces to obtain a base with a water-repellent effect;
impregnations on a mineral and polymer, polymer-cement basis - provide strengthening and reduction of surface porosity.

Equipment and accessories for repair work

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

To pre-clean concrete you will need sandblasting machines, high-pressure apparatus and the high-pressure stations that create them

This group includes the following:

mobile power plants of the required power;
compressors;
rotary hammers and jackhammers;
construction vacuum cleaners;
grinders, grinders;
chisels, scraps, shovels, trowels;
metal brushes;
buckets, containers;
instruments for searching for reinforcement, thermometers, instruments for determining the viscosity of a solution, the strength of concrete;
films to protect the solution from drying out and overheating.

Concrete repair technology

Regardless of the type of material selected, the work process follows a single technological sequence.

The bottom line is this:

preliminary preparation of the base;
cleaning of reinforcement, cleaning of reinforced concrete structures, laying additional reinforcement (if required);
dust removal;
if necessary, formwork is installed and surfaces are moistened;
preparation of working solutions;
application and care.

Preparing concrete surfaces for repairs

Before any manipulations begin, the work site is fenced off, lighting is organized, and mechanisms, tools and equipment are prepared. All equipment is checked to ensure it is ready for operation. idling . The preparation method depends on the degree of damage to the concrete, the volume and type of defects, and the type of repair composition. Before preparation begins, if necessary, eliminate leaks in the area being repaired.

Preparation can be done in the following ways:

mechanical– use rotary hammers, jackhammers, picks, pneumatic hammers, shot blasting machines, sandblasting machines, grinding equipment and cutters.
thermal– use oxygen or propane torches. Surface heating should not exceed 90 degrees. This method is good for small depths of damage (up to 5 mm), if the concrete is contaminated with rubber, oils, and residues of other organic compounds. Heat treatment is always followed by hydraulic or mechanical treatment;
chemical– use special compounds. The method is implemented only where the mechanical method cannot be used. After etching, the surface is always washed with water;
hydraulic- use high-pressure apparatus (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 hammer drills, chippers, and concrete breakers. They produce a layer with insufficient thickness (up to 20 mm), 10-15 cm wide, acting along reinforcing bars, peeling protective layer, loose concrete with shells, structural damage.

After cutting, the surface should be rough and textured without dust, stone chips and other contaminants. Reinforcement that is damaged by corrosion and cannot be cleaned is replaced. The rods protruding to the surface should be cut out. In some cases, an integrated approach is possible during preparation.

Preparation of repair mixtures

Repair compositions based on dry mixtures 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 quantity of the mixture is prepared taking into account the viability. When mixing with water, follow the manufacturer’s recommendations, strictly observing the ratio of water and cement material. On average, 1 kg of dry powder requires 0.12-0.13 liters of water.

When preparing solutions, you must have clean containers, measuring containers for dosing the components, a viscometer, and a thermometer.

Preparation of injection solutions:

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

Immediately before using the solution, a hardener is introduced, followed by final mixing for 2-3 minutes.

Preparation of sealing mastics:

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

Preparation of composite materials:

mixing of 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 and without the installation of formwork. In the latter case, small defects (with a depth of no more than 3 cm) are eliminated by filling the cavities with ordinary concrete, mortar, or polymer concrete. More serious damage is always filled with concrete with the installation of formwork and reinforcement.

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

The concrete solution is supplied to the repair site manually with subsequent compaction using deep vibrators. If bulk solutions are used, vibrators are not used. The compaction process is considered complete if laitance appears on the surface and the air flow stops.

At manual application repair material is spread with trowels and spatulas. The permissible layer thickness is 5-50 mm.

The repaired area requires maintenance, for which polyethylene film or a film-forming composition is used. After removing the formwork, all protrusions are removed, possible defects are repaired. Voids and cavities in places where technological seams are installed 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, combining sealing with injection work.

Concrete repair using composite materials

Such work is carried out in cases where it is necessary to strengthen the structure without significantly changing the geometry and making the structure heavier. Preparation is carried out using sandblasting or grinding machine. Next The work area is primed using an epoxy primer. The drying time of the layer is 3-12 hours.

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

After preparing the repair composition, it is applied to the surface using rollers or brushes. If quartz sand is introduced into the mixture, usually use trowels and spatulas. Next, the surface is leveled and smoothed.

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

Repair of protective layer

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

The technology can be adopted as follows:

working out damaged areas with a diamond circular saw;
removal of damaged concrete using high-pressure apparatus or pneumatic tools;
cleaning of fittings using high-pressure apparatus or chemical methods;
protection of fittings with anti-corrosion compound;
additional mesh reinforcement (if the embedment depth exceeds 5 cm);
saturating the old base with water;
applying repair mortar by spraying or torquetting. If the amount of work is small, use a trowel;
leveling the layer with a trowel;
surface care using film-forming compounds.

Crack sealing technology

Cracks in concrete are repaired only after the causes of their formation have been discovered and eliminated. The development of cracks must be completed. Sealing begins when the waterproofing defects are corrected, after the moisture accumulated in the defects has been released.(the base must be dry).

The surface should not contain chips, shells, areas of peeling, cleaned old paint, dirt using water jet systems.

The repair method depends on the size of crack opening and the effect of damage on the load-bearing capacity of concrete:

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

Serious defects are stitched 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 with injection. If the defect is active, mandatory sealing is carried out using sealing thiokol mastics. If the crack is deep, additional sealing cords are used. This is a proven method of waterproofing.

Concrete injection repair

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

General repair recommendations are:

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

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

When injecting deep cracks (depth over 45 cm, width over 1 mm), high-pressure injection technology is used. Here you will need hand pump, packers. Light portable membrane-type sediments with controlled supply of the composition into the cavity showed effectiveness.

Such work contains the following stages:

installation of packers;
expansion of the spacer seal;
introduction of the composition into the package until failure. The fluid should come out of the adjacent packer;
after completion of the 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 nipples being removed from the packers, leaving only the lower end (pioneer). Next, prepare a working solution and pour it into the pump. A hose is put on the lower pioneer packer and the compound is injected.

The injection solution 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 sequentially fill the entire defect. The solution injection rate should increase gradually, but not higher than 40 Bar. Typically the operating pressure is 20 bar.

Torquetting of concrete

Torquet concrete materials successfully used for restoration and repair work. In this way, shells, cracks, and damage are sealed. The base must have load-bearing capacity, be durable, and clean. It is permissible to torquet reinforced concrete surfaces, work on metal mesh. Before work begins, the concrete is moistened, but the presence of puddles is unacceptable.

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

Work order:

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

Safety precautions when carrying out repair work

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

Concrete repair work is carried out using ladders, scaffolding, and safety belts. Special attention TB is given when working with epoxy resins and polymer concrete. Workers must undergo training in fire danger. Each person is provided with personal protective equipment and special clothing.

Persons who have reached the age of 18, who have undergone introductory instructions and training, and who are cleared for repairs for health reasons are allowed to perform work.

Repair cost

Average costs for restoration of concrete structures start from 2500 RUR/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 100 rubles / m3. Injection work remains very expensive - from 2000 rubles/linear meter.

Conclusions

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

Waterproofing
Waterproofing of swimming pools, foundations, concrete structures under water pressure, urgent repair of leaks	Dry waterproofing mixtures Waterproofing penetrating mixtures Hydro seals	Application layers: 2-3 or more Consumption: 1.75-2.0 kg/sq.m.
Priming, protective priming of reinforcement and concrete
Strengthening concrete after removing layers of corrosion, ensuring high adhesion, protecting concrete, reinforcement and steel structures, rust modification, waterproofing	Universal soils Primer primers Anti-corrosion primers Anti-corrosion liquids	Application layers: 1-5 Average consumption 0.1-1.1 kg/sq.m.
Repair of walls, ceilings (and other vertical and horizontal surfaces)
Elimination of sinks, chips, cracks, up to 100 mm deep	Repair materials for cement, polymer based, injection formulations	Application layers: 2-3 Average consumption: 2-22 kg/sq.m.
Urgent concrete repair
Repair in the shortest possible time	Thixotropic dry mixes	Application layers: 2-3 Average consumption: from 2 kg/sq.m.
Gravy for equipment
Repair of concrete pavements, high-precision cementing of installed equipment	Dry repair mixtures	Layers of application: from 2 Average consumption: from 1.95 kg/sq.m.
Repair of large concrete areas by torquetting
Repair and restoration of artificial stone, structures exposed to sulfates, repairs using coarse aggregate	Dry repair materials	Layers of application: from two Average consumption: from 2 kg/sq.m.