Means for the repair of concrete surfaces. Concrete repair and restoration

Potholes, chips, cracks - all this can happen to any concrete surface. In this article, we will tell you how and with what mixes 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 deteriorate. The reason for this may be poor-quality styling, non-observance of the proportions of the components, an aggressive 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. An option 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 such as columns, beams, floor slabs;
for the repair of roads and concrete floors;
to protect concrete structures from corrosion.

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

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

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 cast. The former are used for vertical surfaces, the latter for horizontal ones. It is possible to increase the reinforcing properties with the help of fiberglass.

How to choose a repair compound

Several factors influence the choice of the repair composition:

type of damage
defect size
terms of Use

There are three main types of repair work:

strengthening the concrete surface
leveling the concrete surface
crack repair

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

The most common type of concrete repair is unevenness leveling. Sealing of vertical surfaces is carried out using thixotropic dry mixes. They adhere perfectly to the surface, adhere well to 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 fiber-reinforced fiber. Fast repairs are provided with special compounds. Their solidification time is up to 6 hours. But they have a limitation on layer thickness - up to 30-40 mm.

Horizontal surfaces are leveled with molding 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 durable. One layer can be laid up to 10 cm thick.

Leveling compounds are also used to repair cracks in concrete.

The choice of the 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 fast solidification.

The most famous manufacturers of repair mixes are BASF, MAPEI, SIKA, from the Russian ones - “Lakhta”, “Alit”, “Consolit”, “SpetsRemSmes”.

Leveling the floor

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 according to the laser level.

Next, the screed is poured. Its maximum height should not exceed 35-40 mm. The pre-mixed mortar 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 must 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-leveling compound. They are used in the presence of small defects and uneven areas. The result of use is a perfectly flat surface.

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

Repair of potholes on the floor

At the beginning of work, small cuts are made around the damage with 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 mortar, it is necessary to remove its excess and level the surface using a strip. After complete drying, the composition becomes as strong as possible. The sealed area is sanded.

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

Crack repair

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

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

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

There is one more method for eliminating 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 kerf is filled with repair mixture. In the event that the concrete crumbles, it is worth using a better mixture, if it practically does not produce dust, a cheaper product 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 mixes:

Parameters	"LAKHTA basic repair composition"	BASF MasterEmaco S 488	Sika Monotop 612
Material consumption, kg / dm 3	1,6-1,7	1,9	2,11
Water consumption, l / kg	0,13	0,145-1,6	0,1-0,115
Bond strength to concrete after 28 days, MPa, not less	1,5	2,5	1,5-2,5
Flexural strength after 28 days, MPa, not less	8	8	7-9
Waterproof mark not less than	W12	W16	W16
Application temperature, ° C	from +5 to +35	from +5 to +50	from +5 to +35
Cost, RUB / kg	57	33	86

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

Correctly selected concrete repair mix and well-executed work guarantee an excellent end result.

Andrey Badovsky, rmnt.ru

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 collapse. There can be several reasons for the appearance of cracks, chips, deformations: a violation of the ratio of elements during mixing, mechanical stress, environmental influences, loads, etc. 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 mortars for concrete are of two types:

molding;
dry.

Casting mixtures for concrete are used to fill pre-prepared cracks and recesses. They have the ability to expand and have 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 hardens the surface to be repaired. Casting mixtures are used for the restoration of horizontal surfaces.

Concrete restoration and reinforcement of monolithic structures are also carried out using dry mortars. The high level of frost resistance and strength allows the use of dry mixtures 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 substance that has gained strength, it is often used for waterproofing concrete. 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 road restoration;
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.

Review of popular manufacturers

The requirements for casting and dry mixtures are as follows:

high degree of adhesion to the restored surface (concrete, stone, reinforcement);
exclusion of shrinkage.

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

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

"Emaco"

The Russian company "Basf" manufactures and sells "Emaco" compounds used for repairing damage to concrete of varying degrees of complexity: from small cracks to complex deformations.

"Emaco" 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 surface areas, 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 no more than 40 mm (third degree).
Cracks over 0.2 mm, bare reinforcement, high level of carbonation - the fourth degree, depth up to 100 mm - are repaired with Emaco T1100 TIX, S 466, S560FR compounds.
Severely damaged concrete structures with exposed reinforcement and chips with a depth of more than 200 mm are restored using non-shrinking ("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"

Birss concrete base restoration mix is produced in Russia and is designed for repairs of any degree of complexity.

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

Frost resistance of Birss compounds allows for repairs at low temperatures. They have high adhesion strength, elasticity, density and water resistance.

The advantage of the material is its 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.

Distinguish between bulk and tikstotropic compositions. The first ones differ in the thickness of the applied layer, the slope of the repaired surface and the cost. The price of bulk mixes varies from 800 to 1,000 rubles per 30 kg.

Tikstotropic solutions "Consolit Bars" are:

reinforcing (113 B60);
finishing (115 V50);
repair non-shrinking (111 V30).

The moisture-resistant coating is created by the Consolit Bars 100 mixture, 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"

It is better to repair concrete structures in high humidity conditions using the Ceresit CX5 mixture, which, when hardened, does not shrink and forms a moisture-resistant and frost-resistant coating that reliably closes all defects.

Costs "Cerezit", which has high technical characteristics, is quite expensive - about 2,700 rubles per 25 kg.

Knauf

Waterproofing of concrete is usually done with the Knauf Flechendicht 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. Knauf solution can be used both outdoors and indoors. Price - from 350 rubles per 5 kg.

"Osnovit"

A novelty on the Russian market - "Osnovit Innoline NC60" from "INDASTRO". It 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 per 25 kg.

With the help of a dry leveler "Osnovit Selform T-112", floors and walls of various types of concrete are repaired. Possesses a high level of adhesion and water-repellent properties. Costs from 160 rubles for 20 kg.

"Alit"

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

Being resistant 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"
Fast and convenient concrete repair is guaranteed by the manufacturers of dry mixes "Mapei". 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 the 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. The moisture-resistant and durable composition is suitable for carrying out repair work as soon as possible. The solution, when solidified, forms an anti-corrosion protective coating and is an excellent waterproofing agent.

Price for 25 kg - from 240 to 260 rubles.

How to choose the right repair material

In order to choose the right mixture for concrete repair, a certain algorithm of actions must be followed.

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, components of mixtures and choose a manufacturer.
Calculate the amount of material required 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 (non-shrinking compositions should be chosen).

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

The correct choice of the repair mix guarantees the concrete structures many more years of safe service.

The cost of mixes for concrete repair

The approximate prices for the compositions for restoration are shown in the table below.

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 all the same, the final condition 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 questions about the repair of concrete structures

Most common injuries

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

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

The most common problems include:

Dusting - fine destruction of the surface layer... It occurs as a result of a violation of the pouring technology, as well as with a significant intensity of operational loads. It is eliminated by applying film-forming compounds - silings.
Cracks - are formed when strong loads are applied to a small area, as well as during thermal deformations. In addition, concrete can crack during shrinkage.

Advice!
To avoid the appearance of deformation and shrinkage cracks, it is necessary to take measures even 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 details.
Level drops 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 when cracks or potholes appear, the mixture for repairing concrete will help restore the surface.

Types of mixtures

A variety of compounds are used to carry out repair work. Their assortment is very extensive, but still it can be conditionally divided into two groups. The features of the materials are easiest to analyze by studying the table below:

Mix type	Properties	Application features
Bulk	The use of components that provide increased fluidity allows the particles of the repair mortar to penetrate deep into the damaged concrete, reliably fastening to the base.	They are used to restore defects on horizontal surfaces - floors, screeds, ceilings, etc.
Thixotropic	When mixed with water, the material acquires plasticity, does not delaminate and does not shrink. High viscosity prevents the free flow of the composition from the damaged area.	They can be used both for filling horizontal cracks and for repairing walls. With a certain skill, it is possible to use the ceiling to eliminate defects.

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

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

Self-production

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 effectiveness will be slightly lower, but it is quite suitable for domestic needs.

For cooking we need:

PVA glue or bustilate 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 just before the start of the repair.

For this:

Pour the cement-sand mixture into a container with a wide neck.
Add glue suspension to the dry material, gradually stirring the solution by hand. 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 attachment and mix the composition until completely homogeneous. As a rule, three to five minutes are enough for this.

Damage elimination technique

Preparation of the base

Usually, an instruction is attached to any mixture for repairing concrete surfaces, clearly regulating the process of its use.

To begin with, we need to inspect the damaged area and approximately estimate the amount of material that we need.
Then we remove concrete fragments, dust, debris, etc. from the crack. For small defects, a stiff brush can be used, while large damage is more convenient to clean with a high pressure sandblaster or water jet.
To secure the edges, the crack can be deepened 20-50 mm below the natural fracture line. In the process of splitting cracks, cutting of reinforced concrete with diamond wheels is often used, which allows you to get perfectly smooth edges and eliminate all loose areas.

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

Particular attention should be paid to the reinforcement cage. We clean all metal parts protruding beyond the concrete cover to a shine. Then we apply an anti-corrosion primer to the cleaned rods to prevent oxidation of the material during the hydration of the repair mixture.
If the defect depth exceeds 50 mm, then additional reinforcement must be laid in it. The armature is mounted in such a way that the metal is subsequently covered with a layer of mortar not thinner than 20 mm.

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

Preparation and application of the composition

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

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

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

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

We apply molding 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 higher than the planned level of coverage.
Pour the prepared fluid mixture onto the concrete, evenly distributing it from one edge to the other. This sequence of actions will avoid trapping 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 run a metal strip around the perimeter.

We act differently with thixotropic agents:

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

With an effort we press the composition into the crack, filling it in one pass by 15-25 mm.
After waiting some time for the layer to polymerize, we repeat the treatment until the defect is eliminated.
Smooth the surface with a moistened steel trowel, trying to mask all 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.

To prevent the repair compound from cracking, 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 bottle or hose, after which we cover it with polyethylene or burlap.

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 separation of the protective layer, the formation of voids and cavities on the surface;
the formation of destruction, loose areas, cracks in deeper layers ;
corrosion of reinforcement, mortgages.

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

Control methods

The choice of concrete repair technology depends on the type of damage found 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 concrete service life from 15 to 40 years.

Choosing a material is based on the following indicators:

the degree of responsibility of the structure, bearing capacity, loading;
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 significant defects

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

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

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

The area that is subject to new concreting must be buried and have sufficient thickness... 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 and washed. It is required to expose the aggregate grains, to 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 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 multiple application experience.

The thickness of the repair layer in 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 artificial stone repair:

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 geometry and load-bearing capacity).

Scope of application of dry mixes: accelerated repair, sealing of defects, including concrete, reinforced concrete structures, roadbed with concrete, sealing 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;
repair of concrete is carried out in the shortest possible time.

Flaws:

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

Specifications

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

Thixotropic formulations (MAPEI, BASF, Sika)

This is a type of dry mixes based on high-strength cement, additives, and fractionated sand. Materials containing polymer fiber were especially effective.

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 a high-strength concrete. Application thickness 10-35 mm.

Scope of application: repair of monolithic, precast 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.

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 (Elakor, Technoplast, KrasKO)

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

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

Repair acrylate compounds are used to seal cracks, chips, increase the strength, water resistance of the base. To enhance the positive properties, filling with quartz sand can be carried out.

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

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.

Flaws:

low vitality.

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, apply:

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

Equipment and accessories for repair work

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

Pre-cleaning of concrete will require sandblasting machines, high-pressure washers and high-pressure stations that create them.

This group includes the following:

mobile power plants of the required power;
compressors;
perforators and jackhammers;
construction vacuum cleaners;
grinders, grinders;
chisels, scrapers, 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 selected, the workflow is subject to a single technological sequence.

The bottom line is as follows:

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 care.

Preparation of concrete surfaces for repair

Before the start of any manipulations, the work site is fenced, lighting is organized, mechanisms, tools and equipment are prepared. All equipment is tested to be ready to idle... 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 the start of preparation, if necessary, eliminate leaks in the repaired area.

Preparation can be done in the following ways:

mechanical- use rock drills, jackhammers, picks, pneumatic chippers, shot blasting machines, sandblasting machines, grinding equipment and cutters.
thermal- use oxygen or propane burners. Surface heating should not exceed 90 degrees. This method is good for shallow 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 treatment;
chemical- use special formulations. The method is implemented only where the mechanical method cannot be applied. 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. A layer with insufficient thickness (up to 20 mm), 10-15 cm wide is produced, acting along the reinforcing bars, a peeling protective layer, loose concrete with cavities, structural damage.

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

Preparation of repair mixes

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 mixer attachment.

The amount of the mixture is prepared taking into account the pot life. When mixing with water, they are guided by 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, it is necessary to have a clean container, volumetric dishes for the dosage of the constituent components, a viscometer, and a thermometer.

Preparation of injection solutions:

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

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

Preparation of sealing mastics:

the required volume of epoxy resin is placed in a clean container;
introduce a plasticizer, a hardener;
the composition is mixed;
in the process of mixing, a filler is introduced into the mixture until a pasty homogeneous consistency is obtained.

Composite materials preparation:

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

Repair of defects made during construction

The elimination of such defects can be realized in two ways: with and without formwork installation. In the latter case, small defects are eliminated (at a depth of no more than 3 cm) by filling the cavities with ordinary concrete, mortar, polymer concrete. More serious damage is always filled with concrete with the installation of 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 former is treated with primers.

The concrete solution is fed to the place of repair by hand with the following compaction with deep vibrators. If bulk solutions are used, vibrators are not used. The compaction process is considered complete if cement laitance has appeared on the surface and air has stopped escaping.

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

The repaired area requires care, for which a polyethylene film or a film-forming composition is used. After removing the formwork, all protrusions are removed, possible defects are repaired... Voids, cavities in the places of the device 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 repaired with sealants, if necessary, 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 significantly changing the geometry and weighting the structure. Preparation is carried out using a sandblasting or grinding machine. Further the work site is primed with an epoxy primer. Drying of the layer is 3-12 hours.

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

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

If defects were found in the concrete, they are filled with working composition flush with the floor level. Leveling is carried out with a sharp trowel. When the finished layer has gained the required strength, sanding and pore sealing are carried out... In this case, they work with epoxy resin, which is applied with a roller with an average consumption of 0.2 kg / m2.

Repair of the protective layer

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 washers or pneumatic tools;
cleaning of fittings with high pressure washers or chemical methods;
protection of reinforcement with an anti-corrosion compound;
additional mesh reinforcement (if the embedment depth exceeds 5 cm);
saturation of the old base with water;
application of the repair mortar by spraying or torqueting. 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 found and eliminated. Crack propagation must be completed. Sealing begins when the defects of the waterproofing are corrected, after the release of moisture accumulated in the defects(the base must be dry).

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

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

if the damage is minor (the so-called hairline cracks), as a rule, it is enough to apply a protective coating;
if the concrete contains cracks, plus there are prerequisites for further disclosure 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 produced on both sides of the defect in order to expose the reinforcement and set the gap. Further, cleaning with compressed air is carried out and the chamber is filled with fiber-reinforced concrete.

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

Internal waterproofing of cracks

If the crack is inactive, a chamber is cut along its length, filling with polymer solutions is carried out. 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 repair of concrete

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 with special devices. Access to defects is preliminarily prepared, tools and equipment are connected.

General recommendations for repair are as follows:

dry cracks, the opening of which does not exceed 0.3 mm, are sealed. An elastic material is taken into the work, which will not lose its tightness under the operating conditions of the structure;
cracks filled with cement leaching products must also be sealed, since the internal space can be impermeable to injection compounds;
if the defect is periodically flooded, jointing is carried out in the form of a puncture, 15 mm deep, 20-40 mm wide. Next, the filling is carried out with a polymer material;
on cracks with a higher opening, on wet cracks, injection is carried out. Compositions capable of interacting with water are taken into work.

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

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

Such work contains the following stages:

installation of packers;
expansion of the spacer seal;
the introduction of the composition into the package to failure. The slurry should come out of the adjacent packer;
after completion of work and curing of the solution, the removable part of the packer is removed;
the hole is stamped with a repair compound.

Injection begins with the packers removing the nipples, leaving only the lower extreme (pioneer). Next, a working solution is prepared, poured 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 pot life

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

Concrete torqueting

Torquette concrete materials are successfully used for refurbishment and renovation works. Thus, the filling of shells, cracks, destruction is carried out. The base must have a bearing capacity, be strong and clean. Torketing of reinforced concrete surfaces, work on a metal mesh is permissible. 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 seal with anticorrosive compounds before applying a protective coating. Leaks are eliminated with 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 is applied, up to 3 cm thick;
the surface is treated in layers. The number and thickness of the layers are determined by the project.

Safety precautions 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 technology chosen.

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

Persons who have reached the age of 18, who have undergone introductory instruction, training, and are admitted to repair for health reasons, are allowed to perform work.

Repair cost

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 works remain very expensive - from 2000 rubles / running meter.

conclusions

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

Waterproofing
Waterproofing swimming pools, foundations, concrete structures under water pressure, urgent elimination of leaks	Dry waterproofing mixtures Waterproofing penetrating mixtures Hydro seals	Application layers: 2-3 and 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, modifying rust, ensuring water resistance	Universal primers Primers Anti-corrosion primers Anti-corrosive liquids	Application layers: 1-5 Average consumption 0.1-1.1 kg / sq.m.
Repair of walls, ceilings (and other vertical, horizontal surfaces)
Elimination of shells, chips, cracks, up to 100 mm deep	Cement-based, polymer-based repair materials, injection compounds	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.
Equipment gravy
Repair of concrete pavements, high-precision cementing of installed equipment	Dry repair mixes	Application layers: 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 the influence of sulfates, repairs using coarse aggregate	Dry repair materials	Application layers: from two Average consumption: from 2 kg / sq.m.

Concrete repair in the parking lot is shown in full detail in the video:

Repair mixtures are designed to eliminate various defects in concrete structures. Special compounds can be used in winter and summer, they tolerate temperature extremes well, pass water vapor, are not afraid of mold and mildew, have increased adhesion, and provide a quick and strong connection.

The widespread use of concrete is due to a large set of advantages: strength, incombustibility, durability and low cost. Gradually, under the influence of various factors, structures begin to collapse. The reasons are different: non-observance of the proportions during mixing, violation of the technology of laying the solution, mechanical damage, aggressive external environment. As a result, the material loses its design characteristics, cracks and chips are formed.

Additional concreting usually does not give good results, therefore it is better to purchase specialized mixtures for repairs. They help to quickly restore geometry and performance.

Situations in which it is advisable to use them:

multiple chips in the floor;
recesses exposing the reinforcement cage;
cracks more than 0.5 mm wide;
significant dust formation;
base corrosion (deep or superficial);
other defects larger than 0.3 mm.

Types and characteristics of mixtures

In the retail network, they are sold in the form of dry powders, which are sufficient to dilute with water in certain proportions. The ready-made mortar fills the free space in concrete, reliably seals and hardens the defective surface. To impart special qualities (frost resistance, moisture resistance, high hardening rate), a variety of plasticizers, modifying additives, granular aggregates are used.

All of them are conventionally classified according to several criteria.

1. By the complexity of the composition.

One-component - cement with different sizes of filler.
Two-component - epoxy with varying degrees of fluidity.
Multicomponent - liquid polyurethane.

2. By the degree of compression.

Shrinkage - mixtures that shrink when hardened in air. When shrinking, it is difficult to calculate the required number of layers in advance. Depending on the complexity of the repair, they are additionally applied 1-2 times. The main advantage is the low price.
Non-shrinking - special additives with an expanding reagent are included. This allows you to obtain a non-exfoliating and mobile solution that does not shrink and hardens quickly. With it, you can easily repair any base, which ultimately turns out to be strong and durable. The only drawback is the high price.

3. By appointment.

Compositions for concrete structures subjected to increased mechanical stress: load-bearing walls, floor slabs, beams, columns.
Mixtures for strengthening reinforced concrete elements against corrosion, as well as protection against mildew and mildew.
High strength products for road surfaces and screeds. In winter, they provide additional protection against frost.

4. According to the conditions of use.

Casting - for screeds and other horizontal surfaces.
Thixotropic - for correcting defects on the walls.
Frost-resistant - for concrete surfaces outdoors.
Fast hardening - for urgent repairs and leaks.
For industrial and domestic purposes.

With the help of bulk (casting) types, it is possible to repair planes up to 100 mm thick. Fast-setting compositions are used for a working layer of not more than 40 mm.

How to choose concrete mixes?

When buying, you need to proceed from the nature of the defect, the size of the damaged area and the operating conditions. It is better to choose solutions that, after setting, do not delaminate and do not shrink.

The compatibility of the composition with the working surface and the level of adhesion are of great importance. Large manufacturers in their assortment always have proprietary deep penetration soil mixtures that bind concrete and provide reliable adhesion.

When choosing, you need to take into account the scale of the repair. Deep cracks, potholes and pronounced drops are leveled with coarse-grained mortars or fiber-reinforced solutions. For small chips and cracks, it is better to buy a version of increased plasticity with a content of fine fractions.

If concrete is used outdoors, in dampness and other extreme conditions, then the compositions must contain additives that give special characteristics (frost resistance, water resistance, etc.). Correctly selected products and strict adherence to the instructions for use are a guarantee of strength and durability.

Repair technology

For correcting large defects and leveling drops, inexpensive sand-cement mixtures are most often used.

Clean the work surface from dust and debris and degrease.
For better adhesion, prime the concrete with an epoxy primer.
Assess the scale of the repair and calculate the required composition. Experts recommend keeping the screed thickness within 40 mm.
Set up control beacons and add mortar.
Remove excess and level with a strip.
Cover the finished plane with plastic wrap and leave for 2 weeks to gain strength. During this time, the concrete is periodically (more often in summer) moistened with water to avoid cracking.

If the size of the defects is insignificant, then for horizontal planes it is better to buy self-leveling liquid types with increased plasticity.

2. Repair of cracks.

First, all the cracks are widened and cleaned. To do this, you need to cut grooves around them to a depth of no more than 50 mm. It is convenient to do this with a diamond wheel or grinder. Then pick out the debris with a chisel or rock drill. Clean the working area with compressed air or with a vacuum cleaner, prime and apply the agent.

Gradually fill cracks on horizontal and inclined surfaces with mortar, without exerting strong pressure on it.
To eliminate cracks on vertical planes, dry mixes of fast hardening should be used.
Internal voids and very deep slots are filled by injection using a special device - a packer. Remove excess composition that has escaped under pressure with a rail.

After hardening, the surface is sanded.

Review of popular brands

The manufacturer is the Russian company Basf. Mixtures are used to repair defects of varying degrees of complexity.

Emaco N 5100 is chosen for minor damage: cracks, shells, dust formation.
Emaco N 900 and N 5200 are recommended for defects of moderate severity: small chips, crumbling areas.
Emaco S 5400, S 488 are intended for elimination of the consequences of corrosion, removal of cracks up to 40 mm deep.
Emaco T 1100 TIX, S 466, S 560FR, A 640 - for severely damaged structures with open reinforcement and deep chips.

2. Consolit Bars.

The composition of the Russian production is excellent for the restoration of vertical and horizontal surfaces. It sets quickly and does not shrink at the same time. Has a high degree of adhesion to concrete.

Bulk - for horizontal and inclined planes.
Tikstotropic - for the restoration of walls and various vertical surfaces. The line is represented by repair, finishing, reinforcing and moisture-resistant coatings.

A domestic product designed for the reconstruction of concrete of any complexity.

Birss 28,29,30,30N - for light repairs of cracks and crumbled surfaces.
30С1, 58С1, 59С2 - for restoration of structures of average degree of deterioration.
59S3, 59C - options for serious damage.
RSM, RBM, 600VRS are used in cases of severe damage.

4. Knauf Flahendicht.

Specially designed for repairing concrete defects. Gives the planes vapor and water resistance. Among the many positive characteristics are the absence of toxic components and small packaging volumes (5-6 kg). They are equally used outdoors and indoors.

5. Ceresite CX5.

Repairing mix for the repair of concrete products in high humidity conditions. It does not shrink during hardening and reliably protects against high and low temperatures.

6. Foundations.

Innoline NC60 is a grouting agent used for the restoration of all types of surfaces. It is successfully used for setting up and fixing heavy equipment on a concrete base.
Selform T112 - for walls and floors. It is characterized by excellent adhesion and water repellency.

Price

Name	Packing, kg	Price per package, rubles
Emaco	25	850-1700
Bierss	50	400-450
Knauf	5	350-450
Ceresite	25	2700-3500
Consolit bars	30	800-1500
Founding Innoline NC60	25	800-1200
Osnovit Selform T112	20	160-250
SW	25	240-260
Mapei	25	850-1300
Alit	25	1100-1700