We repair cracks in concrete

Many homeowners are interested in what to do with cracks in concrete, as this is a fairly common problem for holiday homes and country houses.

Concrete is used in various areas - for pouring floors of apartments and houses, industrial premises, roads, for erecting a foundation.

This material weakly withstands tension, during the drying process concrete structures are narrowed, which can cause various defects and openings.

This is particularly true for concrete floors or foundations.

In addition, cracks often appear due to corrosion of metal fittings, temperature instability, various negative influences.

This defect is very dangerous and common, and in order to solve the problem, you need to know why it arises, what are the reasons for the disclosure.

Specialists identify such causes of cracks in concrete:

• A violation of the technology of manufacturing the mixture is still in the factory, when the ratio of water and cement is broken.
• Because of this the brand of the composition does not match the specified. In addition, prolonged transportation leads to "welding" of concrete;
• Errors in calculations are also frequent reasons for the formation of cracks. A lack of reinforcement or a heavy load harms the integrity of the concrete cover. It is very important to adhere to the norms of SNiP when implementing all calculations;
• Complex geological conditions. Not always the calculations take into account the characteristics of the soil on the ground;
• Incorrect mixing technology for laying. Often, in order to fit more conveniently, it is diluted with water, which prevents concrete from gaining strength. In addition, improper compaction of concrete and the dismantling of the formwork, as well as neglect of the rules for laying reinforcement according to the norms of SNiP, will subsequently lead to the deflection of concrete and the formation of cracks;
• Violation of the rules for the care of freshly laid concrete, especially when it comes to laying in hot weather, when moisture evaporates too quickly from the coating;
• Construction of various facilities that have not been accounted for in advance in the calculations;
• . It is not always possible to correctly select the type of foundation according to the rules of SNiP, because of this, deflections and cracks may occur during the operation of the building;
• Another frequent cause of cracking is the rusting of the reinforcement, resulting in a larger volume of metal and tearing the concrete from within.

Crack varieties

To know how to eliminate cracks in concrete,to what type does it belong:

• End-to-end cracks occur with tensile forces;
• Surface cracks appear after the drying of concrete due to a violation of the formulation of the solution;
• Cracks in the stretching zone appear when bending and are directed across to reinforcing bars;
• Cracks located at an angle to the reinforcement, which arise under the influence of shear force;
• Parallel reinforcement shrinkage cracks that arise due to ground punching, uneven shrinkage or incorrect anchoring. Because of such cracks, shrinkage and deformation of the foundation and the entire structure occurs. Shrink cracks can also appear if the calculation of the load was made not according to the rules of SNiP;
• Small cracks that appear when temperature drops;
• Hair cracks occur for the same reason as the previous ones, but usually their depth does not exceed a few millimeters.

Having determined the causes and types of cracks are determined with the type of repair work.

Repair of cement mortar and mixtures

This type of repair can be considered the simplest and at the same time the weakest. This temporary partial filling of cracks in the floor, walls and foundation in both dry and wet rooms.

Such filling of cracks does not seal them, but protects against contamination for some time and prevents their further unfolding for a while.

Begin repair by the rules of SNiP with the preparation of the disclosure itself.

It should be checked for chips, since in the future other cracks and openings may form. The chisel passes along the entire length of the crack to make it wider.

Hidden chips that appear during operation should be deleted immediately.

Next, clean the crack with water and a brush to remove various dirt, you can also use a vacuum cleaner. Remains of water must be collected with a sponge.

Use a spatula to also deepen the crack to 5 mm to keep the solution stronger.

For repair make a solution of 3 parts of sand and 1 part of cement, in which also need to add PVA glue. The solution should be thick enough.

Pour it into the crack with a trowel, and moisten from above. If you carry out repairs using a polymer mixture, and do not use a concrete solution, you do not need to wet the compound.

In the middle cracks the reinforcement is usually visible, it needs to be cleaned and covered with a special agent that will prevent corrosion. Next, you need to make grooves and put pieces of reinforcement in them 4 mm.

Now evenly over the entire surface, we apply an adhesive compound, so that the thickness of the layer is about 3 mm, and without waiting for drying, you need to fill it with a solution.

The solution needs to be compacted so that it gets into all the recesses and irregularities, and the surface is leveled with a wooden strip, which must be moved along the surface of the solution to the right and left and on itself.

If the gap is very deep, it is advisable to stack the solution in several passes. At each stage, the surface should be slightly sprayed with water.

To make the surface of concrete perfectly smooth, a special metal trowel will help. When the solution is frozen, the excess should be removed with a spatula.

If the surface of concrete you will paint or cover with a laminate, then such work can be done already a day after the repair is made, but for laying the tiles you should wait longer.

It is important to know that after drying the solution shrinks, so the casting compound is laid slightly above the floor level, and after drying it will fall into its place.

If this still does not happen, with the help of a grinder the surface of the former crack is leveled to the required level.

If you deal with a crack, the width and length of which is large enough, you can process it before repair with a circular with a diamond disc, after which the repair is carried out as described above.

This type of sealing is most often used as a temporary solution, since sealing does not occur during such repairs.

The method is relevant both for dry and for rooms with high humidity, where good waterproofing is required.

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Repair of elastic sealant

The elastic sealant will also help to seal the cracks.

The most popular in this case is silicone adhesive - sealant. Such a sealant is used for both small cracks and for those whose width is large enough.

The repair process, which requires the use of sealant, does not differ from the repair, which uses a concrete composition.

First you need to clean the crack from dirt, make grooves to better bond the material to the surface. Applying glue - sealant on the surface, it also must be moistened.

The sealant, unlike the cement mix, dries out in a short time, which makes this material much more convenient.

However, it is worth the sealant is much more expensive, so this repair is not everyone can afford.

Epoxy resin repair

Epoxy resin and repair epoxy composition are also used to seal cracks in concrete.

First you need to expand the expansion and remove loose concrete and chips. The width of the groove should be no more than 25 mm and not less than 4 mm.

Every 400 mm along the crack, you need to make a transverse groove 150 mm long. With the help of a vacuum cleaner, collect all the garbage and dust and process the seams with a primer.

In the transverse grooves that were made earlier, lay the metal braces for reinforcement. Next, the instructions dilute the epoxy solution and add a hardener.

Sand is also poured into the epoxy solution and poured into the furrows.

Top of the epoxy solution is sprinkled with sand, and after an hour the sand is cleaned with a vacuum cleaner.

Repair of a crack in concrete with epoxy resin is quite economical, and drying takes quite a bit of time. In addition, such treatment of cracks prevents their further movement.

It can be used for dry screeding.

If you need to treat with epoxy resin coating for a liquid medium, the mixture does not need to add sand. Do not pour on top with sand.

Repair of cords and tapes

If you need to cover the cracks in a pool or a water tank, in an underground part of the foundation or on the outer walls of a building where high-quality waterproofing is required, then the methods described above will not be enough for the strength of the structure.

For the treatment of disclosure in such places, a special compound is usually used. The cost of such repairs is an order of magnitude higher than the usual methods, but in a humid environment it fully justifies itself.

For each task on sale there is a special material, you just have to make the right choice.

With the help of these materials, the crack is completely sealed, so the coating will last for more than one year.

Repair is possible both indoors and outdoors, at any time of the year.

Begin the repair, as in previous cases, you need to process the disclosure. After all the excess was removed, and with the help of a vacuum cleaner the furrow surface is cleaned, the width and depth are measured.

This is done in order to correctly choose a self-expanding cord for repair.

In the cut the cord is laid, which must lie without compulsion, freely.

To the bottom and top of the furrow should remain 20-30 mm, so that the cord will further expand. Whichever type of cord you choose, you can not force it.

Now on top of the cord is applied polyurethane sealant, the surface of which is leveled with a spatula. The glue that has come out of the seam is removed with a sponge.

Usually on the packaging it is written which material is preferable for this type of cord or tape, strictly adhere to the recommendations.

If you use this material in relatively dry rooms, where the waterproofing is for insurance purposes only, the finish can be made with cement mortar.

In order to choose the material for repairing concrete, you should familiarize yourself with what these materials are and how they differ from each other.

Today the range of such products is quite wide.

This material consists of polymeric resins and modified clay, and also includes bentonite material or an analogue of it, which binds the surfaces together and seals them.

As for the release form, they are as follows:

1. The cord - the material serves to repair not deep slots 30 - 50 mm;
2. Tape - the material is laid in cracks with a width of 20 - 50 mm and a width of up to 150 mm;
3. Pasta sealant is used to treat small furrows;
4. Mats - fasten layers of concrete screed, and when the old coating - a new layer is laid.

Repair of cracks by injection

The name of this method speaks for itself - injection involves inserting into the cavities formed in concrete special materials "injections".

Injection allows you to repair concrete cover without replacing all concrete coating.

This is one of the most effective ways to repair these defects, which is also quite economical.

Injection involves the introduction of a cement, epoxy or polymer mixture into a gap under pressure, so that the mixture fills any smallest voids and cracks.

Thanks to which the design is very durable and reliable.

This method also performs waterproofing of concrete, for which a different composition is used.

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Prevention of crack formation

Even at the stage of pouring concrete it is very important to make sure that the concrete composition of the floor and foundation is of high quality, in compliance with all proportions.

When laying concrete composition, it is necessary to carefully compact it not only manually, but also with the help of a special tool.

To prevent moisture from freshly-mixed concrete from evaporating at high speed, it can be covered with a damp cloth.

In addition, today there are special products on sale that will protect the concrete coating from the appearance of cracks and chips during contact with water.

Do not neglect these tools, as waterproofing is very important for the integrity of the concrete coating.

Waterproofing walls and foundations with such tools will help prevent further crack opening.

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