Concrete coverings are used in a variety of areas: when installing floors, concreting surfaces in both industrial and residential buildings, highway construction and much more. However, concrete has a low tensile strength, so during the hardening process the mixture contracts slightly and shrinkage of the structures occurs. Because of this, minor and more serious defects appear on the surface. In this case, sealing of cracks in concrete is required, which is carried out according to different technologies depending on the type of damage and the cause of its occurrence.

Types of cracks in concrete

Some beginners or unscrupulous builders prefer to simply cover up a hole or any other defect with putty or mortar. However, before you repair a hole or crack in concrete wall and other reasons, it is worth understanding what exactly caused such troubles.

There are several types of defects:

• Superficial. Such cracks often appear after pouring the foundation during the drying of the sand-cement mortar, if the mixture was prepared without observing the required proportions of the components, low-quality components were used, or there was not enough water in the mixture.
• Shrinkage cracks (also called hairline cracks). Defects of this type are considered the most dangerous, since they cause not only deformation of the fundamental foundation, but also the entire building as a whole. This leads to a decrease in strength. Defects of this type appear when there is an uneven load on the foundation and when improperly selected cement composition.

• Temperature-shrinkable. Cracks of this type appear during the hardening process of the concrete base due to the exothermic reaction occurring between cement and water. Very often, when constructing walls and ceilings, novice builders do not take into account the freedom of deformation, as a result of which temperature stress occurs in the concrete mass and defects appear on the surface.
• Cracks and holes appearing due to poor quality reinforcement. If the frame for strengthening the structure is too weak, it will bend under loads, which will also lead to the formation of defects. In addition, the reinforcing rods may begin to oxidize. Due to corrosion, the material increases in size, tearing the concrete mass from the inside.

Concrete surfaces located outdoors are also susceptible to cracking. In the external environment they contain chemical active substances, which create favorable conditions for the appearance of defects.

In addition, sharp temperature changes, which can occur both on the surface and in the very thickness of concrete, have a destructive effect. At the same time, it has a detrimental effect not only cold air, but also ultraviolet.

It is also worth paying attention to the width of the cracks, since in some cases such defects are not critical.

Acceptable crack sizes

In the construction industry there is such a definition as the permissible crack opening width, which is determined according to DBN V.2.6-98:2009 based on operating conditions:

• The crack size should not exceed 0.5 mm if the concrete surface is not exposed to weather conditions. That is, it is not affected by moisture, low temperatures and ultraviolet.
• The permissible crack opening width cannot be more than 0.4 mm, provided that the structure is exposed to weather influences.
• The width of the crack should not exceed 0.3 mm if the concrete base is located in an aggressive environment.
• It is not recommended to allow the formation of gaps larger than 0.2 mm when we are talking about reinforced structures that are characterized by reduced resistance to corrosion.

Horizontal cracks with a small opening, which often appear in reinforced concrete columns, are also considered non-hazardous.

However, it is important to take into account that there are certain operating conditions under which cracking is not allowed at all:

• if we are talking about reinforced concrete structures that constantly interact with liquids and gases (that is, they must be impenetrable and airtight);
• when using structures that are subject to more stringent requirements for their durability.

Having determined the type of defect and the need to correct it, it is much easier to choose than to repair holes in a wall or any other concrete surface.

Cement mortars

These compounds are very popular due to their low cost and ability to repair minor shrinkage cracks in concrete.

Repairing a crack

Before you begin sealing, you need to check the crack itself for chips around it. If there are any, then in the near future they may turn into holes, so it is imperative to remove all peeling pieces of concrete. After this you need:

• Perform jointing. To do this, using a chisel and hammer, you need to walk along the entire length of the crack so that its depth is at least 5 mm. If necessary, you can use a spatula to create a depression.

• Remove dust using a vacuum cleaner and rinse the resulting depression with water.
• Remove excess water and cover the crack cement mortar(3 parts sand to 1 part cement with the addition of PVA). In this case, you need to ensure that the composition covers the entire space of the recess.
• Moisten the poured cement with water.

Filling the hole

If a hole has formed in the concrete surface in which the reinforcement is visible, the defect can be repaired as follows:

• Clean the hole in the concrete and treat its surface with an anti-corrosion compound.
• Place the pieces in the hole steel wire about 4 mm in diameter.
• After this, the recess is covered with a primer, applying it evenly over the entire surface. In this case, the thickness of the mixture layer should be about 3 mm.
• Without waiting for the mixture to dry, fill the hole with a cement compound for sealing cracks in concrete and make sure that it fills the entire hole. If the hole is too deep, then cement is poured in several stages. In this case, each subsequent layer must be moistened with water from a spray bottle.
• Level the surface with a lath (metal or wood), moving the tool from right to left.

• After the mixture has hardened, excess cement composition must be removed with a spatula and the surface must be plastered. If the crack was too deep, then leveling is done using grinding machine.

Healthy! The cement composition must be poured with a reserve so that it is slightly higher than the floor surface. The mixture will shrink as it hardens.

After 24 hours, the concrete floor can be painted or any finishing material can be laid on it.

However, it is worth considering that such sealing of cracks in concrete will not provide a sealing effect and is not suitable for surfaces that have increased waterproofing requirements. In addition, the cement composition can be considered as a temporary solution to problems. Sooner or later the defects will appear again. If you want to “overhaul” the holes and avoid their appearance in the future, then in this case you can repair the defects using resins, specialized repair compounds based on them, or sealant.

Long-term repair of defects

Deciding how to repair cracks in concrete long term, it is worth paying attention to this defect handling method. Resin and sealing mixtures based on it are suitable for restoring screeds, blind areas and various concreted areas or horizontal surfaces.

Repairing cracks in concrete using such compounds has a number of advantages. First of all, this is the low cost of the mixtures, as well as their quick drying. On the other hand, the resin allows you to securely fix the seams and keep them from subsequent expansion.

So, to eliminate defects you will need to prepare:

• angle grinder and diamond-coated discs;
• vacuum cleaner;
• spatulas and a trough for diluting the composition;
• primer composition for concrete;
• Epoxy (base A and hardener B);
• Fine-grained sifted sand.

Before you repair a crack, you need to clean it of dust and dirt. After this, we carry out the sealing in the following sequence:

• We repair the crack. In this case, the width of the resulting recess must be at least 5 mm.
• Using a grinding machine, we cut transverse seams in the concrete in increments of 400 mm (the length of the grooves is about 100-150 mm).
• We remove the loose layer of concrete and remove dust from the surface using a vacuum cleaner.
• We treat the surface of the defect with a primer, and fix the transverse grooves using repair brackets.
• We prepare a solution from resin (base), hardener and sand according to the instructions on the packaging with the composition.
• We fill the defect with the resulting mixture and quickly level the surface, since the setting time of the resin is only 10 minutes.

The best epoxy compounds

If we talk about the best materials for repairing cracks in concrete walls and other surfaces, the most effective today are considered to be:

• Domestic epoxy resin ED-16 and ED-20 costs about 2,000 per 3 kg. The hardener will have to be purchased separately (costs about 300-500 rubles).
• Epoxy 520 resin from the Czech manufacturer Spolchemie costs 3,500 rubles per 5 kg.
• German composition UZIN KR 416, which will cost 2,700 rubles per 0.75 kg.

Also very popular are compositions from the Italian manufacturer Sika.

However, it is worth considering that this method of correcting defects is not suitable for processing holes that form in concrete foundations experiencing strong pressure from water. In this case, it is worth using a sealant.

Use of sealants and self-expanding tapes

It’s worth saying right away that this method of sealing defects is very expensive, so it is most often used when repairing concrete bowls of country pools. However, despite its high cost, the use of sealant and self-expanding cords has its own advantages:

• the ability to process any type of defect;
• complete tightness;
• possibility of conducting installation work in cold weather conditions.

To work, in addition to the standard set of tools, you will need:

• mounting gun;
• self-expanding tape or cord;
• chisel and brushes;
• sealant for concrete.

However, before covering up the flaw, you need to measure the dimensions of the cracks and purchase desired type sealant and tapes depending on this. For example, if the hole depth is 60 mm, then an 18 x 23 mm cord will do.

The next step is necessary:

• Expand the cracks and remove dust.
• Install the cord into the recess.
• Fill the remaining space with sealant.
• Smooth out the protruding compound using a spatula.

After completing the work, you won’t have to guess how to putty the surface or caulk it. It is enough just to apply the composition and smooth it out.

If we talk about the best lineups of this type, the most popular are:

• Domestic ELASTOSIL PU 20 costs 280 rubles per 600 ml.
• The composition is from the French manufacturer Rubberflex, which today sells for 300 rubles per 310 ml.
• PLOW tape Russian production costing about 260 rubles per linear meter.

Injection

Also, when deciding how to seal holes in a concrete wall in the most effective way, especially if not only a crack has appeared, but also water is flowing through it, you should pay attention to this method.

Injection technology involves the introduction special staff(polyurethane or epoxy resin, microcement or waterproofing mixture) into the thickness of concrete using special injection pumps that create strong pressure.

To perform such restoration of defects it is necessary:

• Make holes in checkerboard pattern on both sides of the gap.
• Install packers in them (special tubes through which the solution is supplied, reminiscent of a dowel) at an angle.

• Pour in the solution.
• Pull out the tubes and cover the surface with the building compound.

So, we looked at how to fix a hole in a concrete wall yourself, but what if we are talking about aerated concrete?

Features of sealing cracks in aerated concrete

Cracks form in aerated concrete as often as in conventional cement-sand monoliths. To seal them, work is performed in the following sequence:

• A layer of destroyed material is removed from a wall or any other aerated concrete surface. building material and cleaning from dust and dirt.
• The gap is primed. To do this, it is recommended to use a 50% aqueous dispersion of PVA and water (1:3 ratio).
• Cracks are sealed depending on their size. If the damage is single and its width does not exceed 0.4 mm, then the gap is widened to 10 mm and any building compound is poured into it (you can use cement or special adhesive for aerated concrete). If the width of the defect is up to 10 mm, then it is better to use porous adhesive composition and widen the gap to 20 mm. If a defect up to 20 mm wide appears, it is recommended to use an adhesive or cement composition, after adding coarse crushed stone from aerated concrete.

After completing the work, it is necessary to cover the treated surface with a sheet of plywood (secure with self-tapping screws) for 3-5 hours.

Concrete coatings have long gained popularity among consumers due to their durability. They are used not only for the manufacture of floors in production workshops or as road surfaces, but also in private housing construction. IN this material will talk about how to seal cracks in concrete, which are often a coating problem.

Their appearance is associated with:

• low tensile strength of the material, when when the structure dries, it contracts and shrinks;
• mechanical and chemical damage to the coating;
• temperature changes;
• corrosion of reinforcement.

Advice: it is necessary to repair any cracks as quickly as possible, regardless of the reasons for their appearance. This is one of the main tasks that can prevent further destruction of the structure.

Repair options

Industrial method
Injection	It is necessary to introduce into cracks and voids polymer materials, injecting them there using “injections”. This method makes it possible not to partially replace the concrete structure. It is often used when deciding how to repair cracks in a concrete wall.
Special repair composition for sealing cracks in concrete	In this case, the damaged surface is treated with a solution consisting of a cement-sand mixture and a polymer additive (furyl alcohol and sulfanol). After it dries, it is necessary to apply polyurethane sealant on top.
Shotcrete	Damaged areas are treated with the same material. An additional layer is applied to the surface, consisting of: · cement; · fractional sand; · organic additives (bitumen, resin, latex). Remember this method increases the mass of the structure, thereby creating additional pressure on the foundation.

At home they use:

1. Cement liquid “dough” - for cracks whose dimensions do not exceed 3 mm.
2. Compositions with epoxy resin.
3. Special repair mixtures.

Tip: if the size of the cracks exceeds 3 mm, use a special mixture (Portland cement 1 part, water and sand - 3 parts each, as well as PVA glue).

There is also such a concept - self-healing of cracks, which implies their spontaneous filling. Typically, the method only works for very small defects no larger than 0.1 mm in size.

Technology

Below you will find instructions that will help you understand the entire cycle of work.

You should first prepare the tools and materials:

• hammer;
• chisel;
• cement;
• sand;
• PVA glue;
• water;
• brush;
• spatula;
• mittens;
• paint brush;
• trowel;
• wooden slats;
• pieces of wire;
• metal smoother;
• sander.

Tip: if you forget to leave technological channels in the foundation, floor or walls, will help you diamond drilling holes in concrete with crowns of the required diameter.

Reconstruction methods

Cement-lime mixture

Now you will learn how and with what to repair cracks in concrete floor and do not make a mistake when using the composition:

1. Conduct preliminary preparation of the work site. To do this, check the crack itself and the area next to it so that there are no chips on it, which in the future may become shallow pits.
2. Before repairing cracks in concrete, take a chisel and hammer and go along the entire length of the defect to open it up.

Advice: if a hidden chip is detected, this piece of concrete should be removed.

1. Clean the surface with water, brush and detergent. You can use a vacuum cleaner to remove dust from the crack. Remove any remaining water with a sponge.
2. Take a spatula and deepen the defect to about 5 mm, then the cement-lime mortar will be able to fill the entire space of the cracks and will hold firmly and for a long time.

1. Prepare the solution by taking 3 parts sand, 1 part cement and add PVA glue to the mixture. Please note that the solution should not be thick or liquid.
2. Take a trowel and pour the mixture into the crack, then moisten it with water.

Tip: if you are using a polymer composition, there is no need to moisten it with water.

If there are cracks in the floor medium size and reinforcement can be seen from them, they must be cleaned and treated with a solution that protects the metal from corrosion. You can also put pieces of wire of the same length and Ø4 mm into the grooves.

1. Apply the adhesive compound with a brush and spread it over all uneven areas. In this case, the layer thickness should be about 3 mm.
2. Fill them with the solution without waiting for the composition to dry.. Try to fill gradually, then the solution will lie more densely.
3. Use a wooden lath to level the surface, removing any excess layer of mixture from it..

Tip: if the defect is very deep and large, apply the solution in several layers, wetting each with a small amount of water.

You can lay laminate or paint a concrete surface literally after 24 hours, but with gluing ceramic tiles you shouldn't rush.

Be sure to remember next rule— the filling layer must be higher than the floor level; the solution will shrink after drying. Carry out subsequent work.

Advice: widen a crack in the floor that has large sizes Cutting reinforced concrete with diamond wheels will help you, after which the process is similar to working with medium-sized defects.

Application of elastic sealant

You can also repair a crack in a concrete floor using elastic sealant, among the variety of which silicone is the most widespread. It is used to repair defects of various sizes.

The process is no different from working with CIS. You will also need to clean out cracks or make additional grooves.

Tip: When applying sealant, it is necessary to moisten the surface.

Its main advantage is its drying speed, which is much faster than that of cement-lime mortar. But, the price of this method will also be higher.

Conclusion

Today you learned the best and fastest way to repair cracks in concrete, and also that repairs must begin as soon as possible, otherwise further destruction of the surface area may occur. This will increase the cost of the process several times ().

This article proposed two main methods for dealing with defects in concrete floors and walls.

The video in this article will help you find additional information on this topic.

Concrete and reinforced concrete structures, having the strength of stone, nevertheless, they have a tendency to crack. Subsequently, cracks in concrete cause first partial and then complete destruction. Therefore, having discovered cracking of concrete, it is necessary to carry out repairs as quickly as possible, using the information in this article.

Cracks in concrete: causes of appearance

To better understand crack repair technologies, it is necessary to consider the types and causes of their occurrence of these defects. Cracks in concrete are classified according to the following factors:

• Depth of damage: hairline, through, superficial.
• Direction of cracks: vertical, inclined, horizontal, curved and closed.
• Type of concrete failure: shear, shear, rupture, collapse.

Reasons why concrete material begins to collapse:

• Shrinkage. are the result of incorrect proportions of components when preparing the solution or improper care behind the freshly poured structure. This type of damage appears in the absence of load and is characterized by: a small opening (up to 2 mm), uniform distribution along the entire length of the structure.
• Temperature changes. At length concrete structure 100 meters, temperature change environment per 1 degree Celsius causes a change in linear dimensions of approximately 1 millimeter. Due to the fact that temperature changes can reach 15 degrees or more during the day, concrete cracks. To eliminate this harmful phenomenon, the technology of “expansion joints” is used. In this case, the distance between expansion joints is calculated individually depending on the dimensions of the structure and other factors.
• Draft. Uneven settlement concrete foundations and walls poses a serious danger to newly constructed structures. Settlement is the cause of the most “bad” inclined cracks. To prevent uneven settlement, soil preparation technology should be strictly followed and the building frame should be erected (load the foundation) after natural settlement - 12 months after pouring.
• Heaving. The phenomenon of soil heaving occurs in winter period. Frozen soil tries to “push” the building out of the ground, which can result in very serious damage. As practice shows, linear movements buildings as a result of heaving can reach 15 centimeters. The formation of cracks from heaving can be prevented by the correct depth of foundation embedding below the level of maximum soil freezing in a given area.
• Corrosion of steel reinforcement and improper reinforcement. In accordance with the laws of chemistry, the corroded metal increases in volume and accordingly begins to “tear” the concrete. Also, incorrect calculation of the reinforcement belt can lead to the appearance of cracks.

Repairing cracks in concrete

The width of cracks in concrete is regulated by the current normative document SNiP 52-01-2003. SNP allows cracks in concrete within the following limits:

• Based on the condition of safety of the reinforcement: up to 0.3 mm with prolonged opening and up to 0.4 mm with short opening.
• Based on the permeability of concrete: up to 0.2 mm with prolonged opening and up to 0.3 mm with short opening.
• For large-scale hydraulic structures: up to 0.5 mm.

Hairline cracks in concrete that has already set and hardened can be removed with a wire brush. There are two ways to seal cracks in concrete that has not yet begun to set and harden: additional vibration until the damage is eliminated, or use cement – sand mortar prepared in a ratio of 1 part Portland cement, 3 parts sand (the solution is rubbed into the defects with a trowel or spatula).

Crack sealing agents

Sealing cracks in concrete that has already completely set and hardened, and sealing cracks in concrete on the street is done with special repair compounds. Most Popular repair compounds for cracks in concrete:

• Concrete composition. It is considered the most preferable for eliminating wide and extensive damage. To prepare the concrete repair composition, sand with low self-stress energy (NC20) is used. The sealer is styrene-butadiene latex, which ensures water resistance and adhesion to the base. The ratio of cement and sand, as well as the sand size, depend on the size of the damage. 1:1 for cracks up to 0.3 mm wide (maximum fine sand or dolomite flour), 1:2 for defects from 0.3 to 3 mm (sand with a fraction size of up to 0.1 mm), and 1:3 for damage more than 3 mm wide (river sand with a fraction size of 1.5 mm). The amount of mixer is taken to be 40-45% of the weight of cement.
• Composition based on epoxy resin ED-20, IMTHF hardener and sand ( dolomite flour or limestone flour. The resin is mixed with the hardener in the ratio according to the attached instructions. Next, fine sand is added to the composition in a ratio of 1 part resin and 1 part sand by volume and fill the crack with any in a convenient way: with a spatula, trowel or knife.
• . Liquid glass for sealing cracks in concrete is used in a mixture with cement and sand as a sealer. In fact, liquid glass is a budget analogue of epoxy resin and is diluted in the proportion of 1 part before mixing with cement and sand liquid glass to 2 parts water.
• A special repair composition for sealing cracks in concrete, offered by manufacturers and retail chains: "REPER", Lugato 5-Minute Mortel (Schneller Mortel) and "Glue Constant Granito".

Repairing cracks in concrete using the injection method is a separate method, because it requires a special technological equipment and special materials.

The technical essence of the crack injection method is to inject polymer or cement mixtures with special additives into the cracks. In this case, a mixture for sealing cracks in concrete , fills all corners of damage and reliably seals the structure.

Conclusion

If we consider current problem How to repair cracks in concrete, the following basic principles can be noted. Cracks must be carefully filled and cleaned for repair, and repair compounds must meet the requirements of climatic conditions, water resistance and minimal shrinkage after polymerization or curing.

Comments:

Many people have a question: how to repair cracks in concrete, can you do it yourself, because concrete structures serve for a long time and reliably until the smallest damage is accidentally discovered that appears on the surface of the structure? There are different techniques effects on the material, which answer the question of how to repair cracks in concrete. It should be remembered that not only old material: fresh concrete must also be checked so as not to see significant damage one day.

Cracks in concrete can occur due to exposure to moisture or deformation of the concrete product.

Causes of cracks

There are many known factors whose influence leads to cracking of concrete structures. The most typical damage occurs in places where excess voltage accumulates locally. Thus, in the zone of bending forces, cracks appear perpendicular to the axis of the reinforcing rod: they can extend from the edge of the structure to the axis. Shear cracks (transverse load) are usually located diagonally to the axis of the reinforcement. Defects may cluster in place anchorage, where the stress concentration is quite high.

Shrinkage processes are a noticeable accumulator of cracks. In this case, both the shrinkage of the structure during operation and the shrinkage of the material during hardening of the mass play a role. Shrinkage of the foundation during soil movement causes unacceptable tensile forces, leading to destruction. The accelerated abnormal rate of concrete hardening can lead to the development of many small surface cracks.

Corrosion of concrete under the influence carbon dioxide, carbonization (in the absence of effective additives) creates conditions for the formation and growth of cracks and microcracks. They work in a similar way chemically. active ingredients external environment: acids, alkalis. Influenced by various chemical reactions favorable soil for cracking appears.

The source of concentration of internal stresses can be a temperature difference on the surface and in the thickness of concrete. Usually the reason for this lies in rapid cooling surface due to exposure to cold air, water, as well as the release of increased heat and accelerated hydration of cement. If the stress concentration reaches extreme values, then cracks will grow in the concrete, going quite deep. One of the causes of surface cracking is thermal and ultraviolet exposure to direct sun rays, especially in hot weather.

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Process standardization

There are cracks in almost any concrete, therefore, taking into account the possible impact of the freezing process of water inside the cavity, the standard allows for the presence of small cracks on the surface of the concrete, but their width should not be more than 0.1 mm. Technological surface cracks directed perpendicular to the axis of the reinforcement bar can reach 0.4 mm if they do not lead to a critical decrease in strength. Defect tolerances are based on mandatory condition control of their growth process. Naturally, it is generally accepted that the presence of minor violations is not critical. It is important to exclude their development and ensure timely.

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Features of concrete repair

When concrete cracks, its repair consists of stopping the process of crack development, filling them with a composition that will not allow water to penetrate them, or covering the material with a layer that protects it from external factors.

The first option is usually implemented in two ways: the injection method and sealing. The second option involves applying a surface layer: putty, primer, paint and varnish coating, waterproofing, etc.

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Injection method

Seal the cracks with your own in an efficient way- use the injection method. This method is based on the fact that the healing composition is supplied into cracks and pores under pressure using special pneumatic or electric pumps, developed for this purpose. Polymer or cement mixtures are used as a filling composition, which quickly fill all voids and, when hardened, seal them. Since the composition is supplied under pressure, the pores are filled as much as possible. To carry out the injection, holes are drilled in the concrete (along the cracks) in a checkerboard pattern. Tubes are inserted into the holes, through which the composition is supplied.

The most common is a concrete composition, which is used to seal large cracks. It consists mainly of cement and styrene-butadiene latex in a 2:1 ratio. The mixture is thoroughly mixed and has a fairly liquid consistency. The mixture hardens within 4 days.

You can use a cement composition that contains cement-sand mortar (proportion 1:3) and styrene-butadiene latex. Portland cement is used as a binder and latex is used as a thickener. In the case where the cracks are less than 0.1 mm, pressure is created only by a pneumatic apparatus. The composition, after hardening, creates a waterproofing layer. Shotcrete is sometimes used to improve quality. The greatest effectiveness of cement injection is achieved when chemically active ingredients are introduced into the composition, ensuring crystallization of the structure. A fairly reliable remedy is a mixture of the brand Viatron-Inject-Grunt.

Modern injection formulations include polymer mixtures. Polyurethane compositions are used in the form of foam and provide reliable crack filling. Acrylic and polyurethane gels provide a hydrophilic structure. Solutions based on silicates, siliconates, and polyalkyl siliconates have high fluidity.

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Sealing method

The sealing method is based on filling cracks with a composition that, when hardened, ensures the tightness of the structure. The method is implemented as follows.

First of all, the damaged area is freed from dusty and flaky concrete, after the entire space is carefully tapped with a chisel. At a distance of up to 30 cm from the crack, the damaged material is removed as much as possible in all directions. The repair and sealing mixture for concrete is placed on the cleaned area with a spatula or trowel. As such a mixture, a cement-sand mortar with polymer plasticizers, epoxy resin or a polymer sealing composition based on polyurethane is recommended.

To increase the effectiveness of the cement composition, you can use the following additive: furyl alcohol (0.35% by weight of solution) mixed with sulfanol (0.02%).

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Do-it-yourself repair of cracks in concrete

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Tools required for work

In order to solve the question of how to fill cracks in concrete, you should prepare the tools in advance:

• Bulgarian;
• construction mixer;
• pallet type container;
• shovel;
• spatula;
• trowel;
• metal brush;
• grinding machine;
• bit;
• hammer;
• chisel;
• paint brush;
• scales;
• thermometer;
• measuring bucket;
• roulette;
• electric drill.

Repair of monolithic concrete structures can be done with your own hands using simple methods. The work is carried out in the following order. The damaged area is thoroughly washed using detergents. Then, using a metal brush, the cracking zone is freed from delamination and other destroyed elements of the material. Using a grinder, grooves are cut across large cracks with a depth equal to the depth of the crack.

Small damages are expanded using a spatula and deepened to 3-5 mm. Reinforcing wires are placed in large slots. A primer layer up to 3 mm thick is applied over the prepared area, and a repair sealing mixture based on epoxy resin or cement-sand mortar (a mixture of cement and sand in a 1:3 ratio with the addition of PVA glue) is laid on top (before the primer dries).

A liquid solution is used for cracks less than 3 mm, and for cracks larger than 3 mm, a proprietary solution or a special mixture is used, consisting of 1 part Portland cement, 3 parts each of water and sand, as well as PVA glue.

Concrete coating is very durable, so it is used in various areas: for floors in the residential sector, in industrial workshops, on highways. This material has a low tensile strength, and when dry, structures made from it shrink and shrink, so the concrete develops defects, which are a common problem, for example, with concrete floors. They can also appear due to mechanical and chemical damage, temperature changes, and reinforcement corrosion. Regardless of the reasons for the cracks, they need to be repaired.

Embedding in concrete becomes main task and serves to prevent further destruction of the entire structure.

In this article we will consider the question of how to repair cracks in concrete. There are several repair methods.

Repair methods

We prepare the solution from 3 parts sand and 1 part cement. Be sure to add PVA glue.

The first method is injection. To do this, polymer materials are introduced into the voids using “injections.” This method allows you to do without partial replacement concrete structure. The second method is to apply a special mixture to the damaged surface, which consists of a polymer additive and a cement-sand mortar. The polymer additives are sulfanol and furyl alcohol. When the mixture applied to the concrete dries and hardens, a polyurethane sealant is applied to it. The third method of elimination is the shotcrete method using concrete mixture, that is, applying an additional layer of the same material to the areas being repaired. This mixture consists of fractional sand, water, cement and an organic additive, which can be resin, bitumen, latex. This method is not always convenient to use, since it entails an increase in the mass of the structure, and accordingly, the load on the foundation increases.

All this applies to industrial repairs. If you need to repair it at home, then liquid cement “dough”, solutions with epoxy resin, and proprietary repair mixtures are used for this. Liquid “dough” is used for defects less than 3 mm, and for defects greater than 3 mm, a proprietary solution or a special mixture is used, consisting of 1 part Portland cement, 3 parts each of water and sand, as well as PVA glue. There is also such a thing as self-healing. It implies spontaneous filling. This self-healing is only suitable for very small ones, the size of which does not exceed 0.1 mm. Let's consider the process of embedding in concrete using the example of repairing a concrete floor. To work you will need the following materials and tools:

When applying elastic sealant also in mandatory moisturizing is required.

• chisel;
• hammer;
• sand;
• cement;
• PVA glue;
• spatula;
• brush;
• mittens;
• water;
• paint brush;
• trowel;
• wooden slats;
• pieces of wire;
• metal smoother;
• sander

Reconstruction options

Cement-lime mortar

Before starting work on removing cement-lime mortar, you need preliminary preparation. First, the crack itself is checked to see if there are any chips near it, since in the future they may turn into shallow pits. Next, using a chisel and hammer, we go along the entire length to embroider it. If a hidden chip appears during this work, then this piece of concrete must be removed immediately. Then you need to use water, a brush and detergent clean the surface. In order to remove dust and debris, it is better to also use a vacuum cleaner. Use a sponge to remove any remaining water. So that the cement-lime mortar fills the entire space and holds firmly and for a long time, we deepen them with a spatula up to 5 mm. The solution itself is prepared from 3 parts sand and 1 part cement. Be sure to add PVA glue. In this case, the solution should not be liquid, but thick. You need to pour the solution using a trowel, and then you need to moisten it with water. This procedure with water is not necessary if you use a polymer composition instead of a solution.

If the crack in the floor is of medium size and reinforcement is visible in it, it must be cleaned and treated with a special solution that will protect against corrosion. To strengthen the grooves, you need to put pieces of wire of the same length, the diameter of which is about 4 mm. Then we apply the adhesive composition with a brush and distribute it over the surface of all irregularities. The layer thickness should be approximately 3 mm. Then we fill everything with the solution, without waiting for the composition to dry. It is necessary to pour gradually so that the solution settles tightly. With the help wooden slats level the surface by moving it towards you from right to left. When the hole is very deep and large, the solution must be applied in several layers, with each layer being moistened with a little water. The surface is perfectly leveled using a metal trowel. After hardening, excess mortar is removed with a spatula. Within a day after the repair, the concrete floor can be painted or laminate laid, but it is too early to glue the tiles and you have to wait a little longer.

It is important to remember that the mortar pouring layer must be higher than the floor surface, since the mortar will shrink after drying. We bring the former crack to floor level using grinder. If the crack in the floor is large, then to widen the gap you will need circular saw With diamond blade. Further, the repair process will be the same as in the case of medium-sized cracks.