How to choose the right repair composition (for sealing cracks) for concrete, concrete floor

Repair compounds for concrete can eliminate deformations and chips in structures. The products are used in different seasons, withstand changes in temperature conditions, are resistant to high humidity, the effects of fungus and mold, have good adhesion and rapid setting of the composition.

The list of popular products includes products from the brands Emaco, Consolit Bars, Birss, Siltek, Knauf, Mapei.

Difficulties of the concrete repair process

Repair of concrete surfaces using mortar or dry mixtures is required when the reinforcement is exposed, the material is destroyed, or the surface cracks down to the crushed stone filler. In the absence of restoration work, the structure may collapse.

There are the following difficulties in repairing concrete structures:

• cement grain has a dense structure and does not absorb liquids, solutions, standard masonry composition does not adhere to the base;
• The typical repair mixture shrinks and peels off on a concrete base.

To restore the integrity of the surface, specialized mixtures are used that are characterized by plasticity, a high degree of adhesion, and strength.

The product formula includes the following basic principles:

• dry polymer-cement and ready-made compositions;
• fibropolymer compounds consisting of sifted sand, acrylic and cement;
• compositions with epoxy resins.

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;
• the ability to carry out 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 the right type of 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 compositions 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 made in Russia costs about 260 rubles per linear meter.

Classification

Repair composition for sealing cracks in concrete is divided into the following types:

• injection molding;
• dry.

To adjust the characteristics, plasticizers, granular fillers, modifying additives, etc. are added to the mixture.

According to the complexity of the composition formula, products are divided into the following subtypes:

• one-component - cement-based with filler of different granularity levels;
• two-component - epoxy differ in the degree of density, ductility and fluidity;
• multicomponent - based on polyurethane, have a liquid consistency.

According to the level of compression, products are divided into the following subtypes:

• shrinkage;
• non-shrinkable.

According to their functional purpose, the following subtypes are provided:

• for structures with high mechanical loads - ceilings, load-bearing wall panels, beams, pillars;
• compositions for protecting reinforced concrete structural elements from corrosion, the appearance of fungus, and damage from mold;
• Products with increased strength for the restoration of road surfaces and building screeds provide additional protection in winter.

According to the conditions of use, products are divided into the following subtypes:

• casting - for horizontal surfaces;
• thixotropic - for correcting unevenness on wall panels;
• frost-resistant - for external repair work;
• quick-hardening - for urgent repair work, eliminating leaks.

Fast acting mixture

Fast-acting concrete repair mixtures harden and dry quickly. The use of heavy loaders is permitted 30 minutes after application of the composition. The mixtures are suitable for a concrete layer no larger than 40 mm. The materials are used for emergency repairs in warehouses, in places where equipment is not allowed to remain idle.

Non-shrink repair product

Shrinkage occurs when the volume of cement stone in the solution decreases during the evaporation of water from the adhesive composition. Deformations can lead to the formation of cracks and chips. A special non-shrinking composition prevents destruction of the concrete base.

The formula of the product includes additives with a special reagent to expand the mass.

The solution is plastic, does not separate, does not shrink and sets quickly. The compositions are suitable for different types of bases, are strong, durable, and are highly expensive.

Thixotropic mixture

The thixotropic mixture is intended for repairing blocks, wall panels on a slope, and horizontal surfaces. When using the product, no auxiliary lathing is required; the product has a high viscosity that prevents spreading outside the treated area.

The dry mixture is based on durable cement powder, mineral fillers, and modifying agents. The mass also includes reinforcing fibers.

After dilution in water, a strong solution is formed that does not create shrinkage. The thixotropic mixture must be applied in a dense layer. For stability in places with heavy loads, reinforcing bars will be required. After hardening, the composition becomes resistant to compression and bending, and vapor permeable.

The product is intended for professional repairmen and restoration work in private buildings.

When used professionally, the mixture is suitable for the following areas and types of structures:

• restoration of damaged surfaces, structural repairs in the event of reinforcement corrosion;
• to eliminate defects that arose during construction;
• to restore the protective layer;
• for filling thin seams;
• for leveling wall panels and fences;
• for mounting foundations exposed to strong mechanical loads;
• for waterproofing work on the roof;
• for repairing boiler houses, thermal power plants, bridges, chimneys, viaducts;
• for restoration of ceilings in basements.

In private construction, compositions are used in the following cases:

• repair of concrete floors, paths, floors, staircases, basements, vegetable stores;
• sealing cracks, chips, grooves;
• restoration of garages;
• repair of structures subject to dynamic loads.

Thixotropic repair materials are not used for finishing smooth surfaces and are not suitable for anchoring or preparing formwork. The installation temperature must exceed +5°C. The thickness of 1 coating reaches 30-35 mm, after 28 days the compressive strength reaches 60 N/mm², elasticity parameters are 25,000 N/mm².

Frost-resistant

Frost-resistant compounds are used to repair concrete outdoors. The product can withstand sub-zero temperatures and temperature changes. The formula of the mixture contains polymer compounds, minerals, fractionated sand, modifying fillers, Portland cement, etc.

The product is used for repairing brick and concrete buildings, cracks in floors, technological holes, restoring smoke, boiler houses, thermal power plants, prefabricated reinforced concrete structures, plinths, for waterproofing building foundations, eliminating defects in monolithic structures, etc.

The main causes of concrete floor defects

There are many reasons for damage to the screed - these can be external or internal influences.

A typical, but even worse, damage to a concrete screed is the appearance of a network of cracks.

• Changes in the soil can have a negative impact on screeds that are poured directly onto the subgrade. Deformations are possible due to poor quality compaction of the base. the cause may be the absence or insufficiency of thermal insulation - with the advent of cold weather, the effect of winter swelling of soils is possible. Another reason is that the screed was poured without regard for the very close location of groundwater.

All these factors can lead to instability of the soil layers, which is reflected in the concrete slab. And this is without taking into account possible seismic shocks.

• Impacts of an internal nature. This item most often includes the use of low-quality screed mortar, as well as pouring carried out in violation of technological requirements. Another factor is the completely natural shrinkage of the structure, which can create very significant internal stresses in the concrete slab, leading to its cracking.
• External influence . This group includes mechanical damage due to the fall of various heavy objects, violation of operating rules (exceeding the permissible load), or from exposure to moisture for a long time.

As you can see, some factors can be foreseen, and try to minimize the likelihood of their negative impact. But there are also reasons of a spontaneous nature, as well as natural aging processes of building structures. So repairing a concrete floor can become an urgent need for any owner of a house or apartment.

Manufacturers

The list of popular repair compounds includes products from the following manufacturers:

• Ceresite;
• Penetron;
• Basf;
• Birss;
• Consolidated Bars;
• Siltek;
• Knauf;
• Industry;
• Mapei.

Ceresit

The manufacturer Ceresit produces different types of building mixtures for concrete foundations. The Ceresit CX5 mixture is a restorative mixture, suitable for repairing concrete structures at high humidity. The product does not shrink significantly when hardened and used, and can withstand changes in temperature conditions. The coating is resistant to high humidity and reliably hides defects. The cost of the composition is high - about 2500-3000 per package of 25 kg.

The composition of Ceresit CN 88 is intended for leveling floor coverings and is durable. The product is laid out in a layer of 5-50 mm and can be used indoors and outdoors. The mass is quickly leveled, the surface can be used 6 hours after restoration. The product is wear-resistant, suitable for mechanized spraying, and environmentally friendly in composition.

The product is suitable for leveling screeds and restoring foundations that can withstand high loads. The mass is suitable for manual application to the coating.

The minimum layer thickness is no less than 35 mm; on the sound and heat insulating layers, the product is laid out with a thickness of no less than 45 mm. Can be used as a base for laying finishing material.

Penetron m500 bond mixture

Concrete repair compositions from the Penetron brand are dry mixes. The formula contains processed quartz sand, fine-grained Portland cement, polymer compounds to improve the elasticity of the product, and mineralized fiber fibers. The mixture must be diluted in the proportions of 170 g of water per 1 kg of powder. Laying the mass is carried out at a temperature of at least +5°C. The surface must be washed with clean water.

The product is laid out in a thickness of 5-35 mm, consumption is carried out in proportions of 1.8 kg per 1 m². The composition can be laid out in several layers, the second coating is applied after 4 hours. It takes 120-150 minutes for the layer to harden. After 28 days, the patch increases water resistance to W14, the strength category is 50 MPa, the adhesion level is up to 1.3 MPa.

Blend Parade

Parad brand compositions are intended for urgent repairs of concrete structures; the coating thickness can reach 60 mm. Laying can be done at a temperature not lower than +5°C. The advantage of the product is the rapid setting of the composition and the high strength of the patch.

After 1 day, the strength of the layer reaches 20 MPa; after 1 month, the coating acquires a strength parameter of 70 MPa, the frost resistance level is F200.

The product is universal, suitable for different types of structures (anchors, foundations, joints, road slabs, hydraulic structures, drinking water tanks).

Emaco

Repair mortar for concrete floors Emaco brand Basf is used for structures of various levels of complexity. Emako N 5100 is suitable for minor deformations (cracks, chips). Products N 900 and N 5200 are suitable for eliminating defects of medium complexity (cracks, collapsed areas).

Products S 5400, S 488 are used to eliminate damage due to the corrosion process, closing cracks up to 40 mm. The company also offers compositions for damaged concrete surfaces with exposed reinforcement bars and large chips.

The manufacturer has developed frost-resistant, non-shrinking, anti-corrosion compounds. The price in Moscow is 850-1800 rubles. for 1 package.

Birss Russia

The concrete repair mixture from the Birss brand is universal and can be used for surfaces of different levels of complexity. Products 28, 29, 30, 30N are applied to eliminate cracks and deformed coatings. Special products (30С1, 59С2 and 58С1) are intended for medium wear surfaces; mixtures 59S3, 59Ts, RSM, RBM, 600VRS are used in case of major damage to structures.

The compositions have frost-resistant characteristics, are used at sub-zero temperatures, have high strength of bonding of elements, have water-resistant characteristics, high density, and plasticity.

Consolid Bars

Products for surface restoration Consolit Bars are suitable for panels located vertically and on floor coverings; the mass quickly holds surfaces together, does not shrink, and has high adhesion. The product line includes self-leveling, thixotropic (for restoration of wall panels), finishing, waterproof and reinforcing mixtures. The cost of production is 800-1500 rubles. per package 30 kg.

Knauf

Products for concrete repair from the Knauf brand are environmentally friendly, do not contain toxic substances, are durable, provide surface waterproofing, and have water- and vapor-proof characteristics. The mixtures are sold in compact packages (5-6 kg). The products are universal and are used for external and internal repair work. The cost of packaging (5 kg) is 350-500 rubles.

Industry

Indastro products are universal and are used for repairs, restoration of structures on foundations, restoration of road surfaces, etc. The composition ensures strong joining of elements, is durable, wear-resistant, does not have strong shrinkage, is water-resistant, and frost-resistant.

Mapei (Italy)

The mixture from the Mapei brand ensures that restoration work can be completed in a short time, does not shrink during hardening, does not deform, and prevents abrasion of surfaces. The special SW series is suitable for reinforced concrete structures and is resistant to temperature changes, precipitation and moisture. After hardening, the coating layer acquires anti-corrosion properties and is suitable for waterproofing work.

The manufacturer's range also includes mixtures:

• epoxy;
• with the addition of resins;
• with high plasticity;
• for repairing cracks;
• for restoration of ceilings;
• for repairing airfield ceilings, tunnels, production workshops, highways.

The product price is about 850-1500 rubles.

Mount Crystal

Mountain Crystal products are intended for the reconstruction of concrete floor surfaces, reinforced concrete floors, walls lined with foam concrete and aerated concrete blocks. The mass is used to seal cracks and placed in areas of chips, holes, voids and traces of erosion. The product is suitable for restoring walls, floor coverings, and ceilings.

Siltek

The manufacturer Siltek offers a composition for repairing defects in surfaces and finishing seams between panels. The materials are frost- and water-resistant, quickly harden, durable, and wear-resistant. Reinforced microfibers are included in the formulas of some products. Products are certified.

The particle size in the mass reaches 2.5 mm, the thickness of the coating reaches 30 mm, after 3 days the strength of the layer reaches 15 MPa, after 28 days - 35 MPa. The product is suitable for use within 30 minutes after dissolving in water.

Frost resistance parameters reach at least 200 cycles, shrinkage does not exceed 1.2 mm/m, abrasion characteristics do not exceed 0.5 g/cm2.

The permissible operating temperature is -30…+70°С. After 3 days, the bending strength parameters reach 3 MPa, after 28 days - no less than 5 MPa. The strength of bonding to the surface is not less than 2.0 MPa.

Types of damage

The choice of method for repairing structures depends on the type of cracks. They are:

• by degree of penetration: superficial - shallow and deep, through;
• by size: hairline (up to 1 mm), medium (from 1 to 10 mm), wide massed (11 mm or more);
• in relation to reinforcement: without exposure, with complete or partial exposure;
• by location: local, spread over all surfaces, corners, edges;
• by impact on the structure: no effect, reducing strength by 5–50%, destroying when strength is less than 50%.

How to choose?

When selecting products, the following parameters must be taken into account:

• type of repair required;
• extent of damage;
• permissible loads on the base;
• location (indoor or outdoor);
• safety, no toxic particles;
• thickness of the mass laying layer;
• volume of raw materials;
• level of protection against ultraviolet radiation;
• shrinkage characteristics;
• resistance to chemicals and sub-zero temperatures.

When choosing the type of product, it is important to consider the following recommendations from experts:

• it is better to strengthen panels located vertically with thixtotropic mixtures, since the products have a thick consistency and hold securely during operation;
• compositions for leveling the surface must have a high adhesion rate;
• The setting period of the mass should be short.

Plastering the foundation with your own hands: from choosing cement to grouting the surface

Regardless of what kind of foundation is made, sooner or later it will still begin to collapse. Cracks and damage appear especially quickly on brick and block foundations. It's no secret that cement is short-lived. It is not able to withstand the influence of rain, and therefore is washed out quite quickly. It goes without saying that every home owner thinks about protecting the foundation. In this case, the best defender will be foundation plaster, and anyone can do it with their own hands.

Application practice

Concrete structures are destroyed if the proportions of substances are not observed, manufacturing technology is violated, due to mechanical deformations, or exposure to the external environment.

The use of special compounds is required in the following cases:

• chips;
• recesses;
• holes exposing reinforcement;
• cracks larger than 0.5 mm;
• intensive dust formation;
• corrosion process in the foundation (deep or surface);
• defects larger than 0.3 mm.

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 introducing a special composition (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 a staggered 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?

Self-production

You can make a repair composition for concrete yourself for work on the arrangement of a private house, outbuildings, etc.

You will need to mix the following components:

• 1 part cement powder;
• 3 parts clean fine sand;
• glue (PVA or Bustilat) with water in proportions 1:3.

You need to mix sand and cement powder, mix with other ingredients and prepare a homogeneous mass. When mixing, use a special mixer. The composition is prepared on the eve of work to prevent pre-hardening. The mixture is suitable for finishing floor coverings, vertical panels, etc.

Ways to improve the quality of the solution

1. Even if all the requirements for the components of a concrete solution are met, sometimes its quality needs to be improved. For example, various plasticizers and superplasticizers allow you to increase strength and ductility while reducing the amount of water. The most famous of them is s-3.
2. Water repellents attract many air bubbles into the solution, thereby slowing down the setting process.
3. In cold weather, it is better to mix the cement mixture not with clean water, but with salt solutions. There are many other additives that change the properties of concrete.

The quality of the finished concrete is also affected by the method of its placement. The most reliable, durable foundation will be obtained if the solution is subjected to vibration . It will allow you to lay the concrete as tightly as possible, without unnecessary air chambers. In the absence of professional devices, the most primitive method is to rotate a steel rod immersed in a newly poured foundation.

Self-preparation of concrete mortar

As you can see, making homemade concrete is not that easy. If you count all the costs for materials and their delivery, then even in the absence of hired labor and a concrete mixer, the amount you will get is no less than what you would spend on purchasing ready-mixed concrete.

In addition to the fairly high cost, there are other disadvantages of preparing the solution yourself. For example, a person without experience is unlikely to be able to correctly determine the water-cement ratio, taking into account the moisture content of the sand and the size of the crushed stones. Subsequently, this will greatly affect the strength of the structure.

Self-production of concrete is justified only in cases where very little of it is needed (less than one cubic meter), or the construction site is located in a place where it is difficult for a car to reach. In other situations, it is better not to take risks and purchase concrete produced at a concrete concrete plant. The main thing is to choose a trusted manufacturer. In this case, you will save yourself from unnecessary expenses and unjustified loss of time, and your home from destruction associated with the quality of the foundation.

Source

Plastering

This type of mixture has been used for exterior decoration of houses for a very long time. The most commonly used mixture is sand and cement. But now the construction market is ready to offer a lot of new options for finishing, so plaster is more often used for rough finishing. Plaster mixtures are divided according to the type of binder component:

• mineral plasters;
• polymer putties on water;
• polyurethane and epoxy;
• silicone;
• silicate.

Mineral plaster is more often used as a decorative material . But it is worth separating decorative plaster for interior and exterior work. Its solution can be thick or semi-liquid. Water is used as a solvent. Mineral plaster can be prepared directly on site. Mineral plasters have affordable prices, and among their physical properties they are famous for their resistance to fire and high vapor permeability.

What kind of dry construction mixture factories exist in Russia is indicated in this article.

Walls covered with mineral plaster breathe well, but allow water to pass through, which is bad for the surface of the walls. This type of plaster also has a number of disadvantages: the elasticity of the material is extremely low, and the degree of adhesion is also low. Therefore, when choosing a mixture for exterior wall decoration, keep in mind that mineral plaster will not adhere well to a smooth surface.

The article shows how to use dry building mixtures for floor screed.

Water-based polymer plasters

Water-based mixtures are characterized by low toxicity, which is extremely important. Coatings based on this have both their advantages and disadvantages. Among their positive properties, they are distinguished by an average or optimal degree of water resistance, they are elastic, withstand external factors well, and are resistant to ultraviolet radiation.

The main disadvantage is that polymer plaster tolerates temperature changes very poorly. It is impossible to apply the material to a surface that is heated to 90 degrees.

GOST cement-sand mixture and other technical data are indicated in the article.

Polyurethane and epoxy

They also belong to polymeric materials, but on an anhydrous basis. A polyurethane base or epoxy is used as a binding component. The polymer base is applied to almost any surface, be it brick, stone, concrete.

Polymer plasters based on this type have a highly wear-resistant coating. Good adhesive properties are inherent in this type of mixture. It withstands external factors very well, is non-flammable, and has a good degree of hydrophobicity. Of course, there are also disadvantages. If the surface temperature exceeds 140 degrees, the binder will begin to decompose. And when decomposed, this component releases toxic substances. When reaching this temperature, polyurethane polymer plasters will release cyanide, and epoxy plasters will release chlorine.

The consumption of cement-sand mixture per 1 m-3 is indicated in this article.

Silicone plasters

In order to apply silicone plaster, it is recommended to pre-treat the walls with a silicone primer to achieve a more dense base. Silicone is used as a binding component. Silicone plaster for facades appeared on the market relatively recently and has an improved composition.

Silicone is resistant to precipitation and also has a good degree of hydrophobicity. The finished coating has antistatic properties. It is not afraid of prolonged exposure to solar components. Silicone mixtures have a wide range of colors. And maintenance of the finished base is practically not required.

You can learn how to calculate a dry mixture for floor screed by reading this article.

Silicate plaster mixtures

The binding component in this type of mixture is liquid glass. Such plasters are produced in finished form. Silicate plasters have high vapor permeability.

They are often used where acrylic plaster cannot be used. On walls, for example, cellular concrete will hold up well. Plaster is easy to maintain due to the fact that it does not attract dirt and dust. This is due to the neutral electrostaticity of the material.

Foundation preparation

Plastering the foundation with your own hands is not a difficult task, but it is painstaking. In order to apply plaster efficiently and correctly, the foundation must be prepared in advance. In this case, you must adhere to 4 rules:

• For brick or block foundations, it is necessary to clean the joints, which is done using a thin spatula. It is necessary to carry out cleaning so that no traces of the old solution remain. A stiff bristle brush will help get rid of crumbs and dust.
• In the case of a foundation on a concrete strip, cracks and fractures can often occur. It goes without saying that finishing the foundation with plaster can only be done here after these defects have been eliminated. In order to eliminate cracks, it is necessary to stitch out the gaps, and then sweep away the dust with a brush.