We protect concrete from corrosion. Concrete corrosion

Concrete is an artificial stone material consisting of cement, sand, water and crushed stone. When the compacted mixture of binder (cement) with aggregate hardens, concrete is formed. Crushed stone, sand, gravel can be used as a filler.

- the process of destruction of its structure, embrittlement under the influence environment. concrete can be of three types.

Types of concrete corrosion:

1. Dissolution of the constituent parts of the cement stone.

This is the most common type of concrete corrosion failure. Concrete products are used mainly in outdoors. At the same time, they are exposed to atmospheric precipitation and other liquid media. Integral part concrete is the resulting calcium oxide hydrate (Ca (OH) 2) - slaked lime. This is the most easily soluble component, so over time it dissolves and is gradually removed, while violating the structure of concrete.

2. Corrosion of concrete during the interaction of cement stone with acids contained in water.

Under the influence of acids, the corrosion of concrete proceeds either with an increase in its volume, or with the washing out of easily soluble lime compounds.

The increase in volume occurs according to the reaction:

Ca(OH) 2 + CO 2 = CaCO 3 + H 2 O

CaCO 3 is insoluble in water. Gradually, its deposition occurs in the pores of the cement stone, due to which there is an increase in the volume of concrete, and further its cracking and destruction.

When concrete comes into contact with aqueous solutions of acids, easily soluble calcium bicarbonate is formed, which is aggressive for concrete, and in the presence of water it dissolves in it and is gradually washed out of the structure of the concrete stone. The formation of calcium bicarbonate is described by the reaction:

CaCO 3 + CO 2 + H 2 O \u003d Ca (HCO 3) 2.

In addition to dissolution, the chemical corrosion of concrete is also observed:

Ca (OH) 2 + 2HCl \u003d CaCl 2 + 2H 2 O,

in this case, salts of calcium chloride are washed out.

If the destruction of concrete occurs under the influence of water sulfates, pozzolanic Portland cement is used, as well as sulfate-resistant Portland cement.

3. Corrosion of concrete due to the formation and crystallization of sparingly soluble substances in the pores.

In addition to the above-described corrosion destruction of concrete, in the presence of microorganisms, biocorrosion may occur. Fungi, bacteria and some algae can penetrate into the pores of the concrete stone and develop there. The products of their metabolism are deposited in the pores and gradually destroy the structure of the concrete stone.

During corrosion of concrete, several types of destruction usually occur simultaneously.

Corrosion of concrete (reinforced concrete structures) under extreme operating conditions

Extreme conditions include exposure to concrete stone of very low temperatures and various substances with increased aggressiveness.

A fairly common case of concrete corrosion under extreme conditions is the destruction of the material under the influence of sulfates (chemical corrosion of concrete). First of all, aluminate components of concrete stone and calcium hydroxide interact with sulfates. The interaction of aluminate minerals and sulfates is highly undesirable. As a result, several modifications of hydrosulfoaluminate are formed, the most dangerous of which is ettringite(3СaO Al 2 O 3 3CaSO 4 32H 2 O). This salt, as it grows (crystals increase), forms a very high voltages, which significantly exceed the strength characteristics of cement stone. As a result, under the influence of solutions containing sulfates, the corrosion destruction of concrete proceeds very intensively.

When calcium hydroxide interacts with sulfates, CaSO 4 2H 2 O is formed. Over time, the substance accumulates in the pore space of concrete, gradually destroying it.

The resistance to sulfate-containing environments depends very much on the mineralogical composition of the concrete. If the content of minerals based on aluminum and tricalcium silicate is limited in cement, then it is more stable in this environment.

If iron reinforcement poured with concrete is used in the structures, i.e. reinforced concrete, another type of destruction is possible - corrosion of reinforcement in concrete. Under the influence of environmental waters or in the presence of hydrogen sulfide, chlorine, sulfur dioxide in the air, the reinforcement in the middle of the concrete rusts and corrosion products of iron are formed. In terms of volume, they exceed the initial volume of the reinforcement, which leads to the emergence and growth of internal stresses, and subsequently to cracking of concrete.

Through the pores in the cement stone, air and moisture penetrate to the reinforcement. Their supply to the metal surface is not carried out uniformly, which is why different potentials are observed in different parts of the surface - electrochemical corrosion proceeds. The rate of electrochemical corrosion of reinforcement depends on the moisture permeability, porosity of the concrete stone and the presence of cracks in it.

The presence of dissolved substances in water increases the corrosion of reinforcement with an increase in electrolyte concentration.

With prolonged exposure of concrete to air, a very thin (5–10 µm) layer is formed on the surface. protective film, which does not dissolve in water and does not interact with sulfates. The process of formation of a protective film under the influence of atmospheric carbon dioxide is called carbonization. Carbonization protects concrete from corrosion, but promotes corrosion of reinforcement in concrete.

It is impossible to reinforce concrete, which includes calcium chloride (more than 2% by weight of cement). Calcium chloride accelerates the corrosion of reinforcement both in air and in water.

Corrosion protection of concrete reinforcement

There are several ways to protect steel reinforcement in concrete from corrosion: improve the environment surrounding the metal (i.e. use high-quality concrete special composition, the introduction of inhibitors); additional protection of concrete reinforcement against corrosion (films, etc.); improve the characteristics of the metal itself.

Concrete itself is located around the reinforcement, therefore it is concrete that is the medium surrounding the metal. To extend the service life of the reinforcement, it is necessary to improve the effect of concrete stone on steel. First of all, it is necessary to exclude or, if this is not possible, to minimize the substances that make up the concrete, which contribute to the intensification of the process of corrosion of reinforcement in concrete. These substances include thiocyanates, chlorides.

If a reinforced concrete product is operated under conditions of periodic wetting, it is necessary to impregnate the concrete with special impregnations (bitumen, petrolatum, etc.). This will greatly reduce the permeability of the concrete. With constant saturation of the concrete stone, the corrosion of reinforcement in concrete is practically reduced to a minimum. This is explained by the fact that the penetration of oxygen to the metal surface is very difficult, and the cathode process is significantly retarded.

To extend the service life of the metal base of reinforced concrete, the concrete is ennobled. During the formation concrete mix corrosion inhibitors are added to the composition.

To protect reinforcement against corrosion in structural and heat-insulating concretes, the method of ohmic limitation is widely used. The bottom line is that the humidity of the concrete itself should not exceed the equilibrium value at a relative humidity of 60%. Then the processes of reinforcement corrosion almost stop, because. there is a high ohmic resistance of moisture films near the surface of the reinforcement. This method is not so simple and not effective in areas with high humidity and frequent precipitation.

Good concrete should have an initial passivating effect on the reinforcement. Concrete products completely dry out in about 2-3 years. If the climate is dry, then a little faster. It is at this time that the strongest corrosive destruction of the reinforcement occurs, because. it is in a damp concrete environment.

A good way to protect the reinforcement of concrete from corrosion is the preliminary passivation of the surface of the reinforcement, as well as the formation of oxide protective films under the influence of the aqueous alkaline environment of the concrete stone. The protective properties of the film are enhanced by introducing passivators into the concrete mixture. Often sodium nitrite is used in an amount of 2 - 3% of the initial cement weight.

Corrosion protection of concrete

To protect concrete from corrosion and extend its service life, it is not enough to use only one type of protection. So that concrete does not succumb to the harmful effects of the environment, preventive measures are taken to protect it already at the design stage.

Operational and preventive measures provide for the neutralization aggressive environments, sealing, intensive ventilation during the operation of cement stone in the room (for air drying).

Rational design plays an important role in preventing concrete from further failure. At the same time, it is necessary to give the concrete surface a structural form that will exclude the accumulation of water and various organic matter. In addition, it is important to ensure the free flow of liquid from the surface. This can be achieved by using drainage or by forming a concrete surface with a slope.

Protection of concrete against corrosion can be divided into primary and secondary.

Primary protection of concrete against corrosion provides for the introduction of special additives into the composition of concrete during its manufacture and formation, while changing its mineralogical composition. This method is considered the most effective.

Various water-retaining, plasticizing, stabilizing, chemical modifiers, amorphous silica, etc. can serve as additives.

In addition, focusing on the operating conditions of the cement stone, during its formation, the composition that is optimal for these conditions is selected. For example, for cements operating in sulfate-containing waters, the C 3 S content is reduced.

Pozzolanization is often used. Acid hydraulic additives containing active silica are added to Portland cement.

Ca (OH) 2 + SiO 2 nH 2 O \u003d CaO SiO2 (n + 1) H 2 O,

The resulting calcium hydrosilicate is more stable than Ca(OH) 2 .

Chemical additives can improve a lot operational properties concrete. Increase its density, as a result of which aggressive agents in the pores slow down the speed of their movement. Reinforcement, being in dense concrete, is less susceptible to corrosion damage.

Also, with the help of chemical additives, it is possible to significantly increase the number of conditionally closed pores. As a result, the frost resistance of cement stone increases significantly.

The most common chemical additives that are used to protect concrete from destruction are: plasticizing, antifreeze, sealing, water-repellent, air-entraining, setting retarders, gas-forming, reinforcement corrosion inhibitors.

Some additives have a double effect, i.e. improve several indicators at once. Others may improve one and downgrade the other.

The most promising and common are the following additives.

Mylonaft. It is a plasticizing additive consisting of a mixture of sodium salts of water-insoluble organic acids. It helps to increase the homogeneity of the concrete mix, while reducing the friction between its individual grains. Also involves air. Produced and supplied in the form of pastes. It is necessary to introduce into the concrete mixture from 0.05 to 0.15% by weight of cement (in terms of dry matter). If the specified dosage is exceeded, the compressive strength of concrete decreases.

Mylonaft increases the water resistance of concrete stone by two grades, frost resistance by two times, resistance to mineral salt solutions, and crack resistance.

Sulfite-yeast brew SDB. This is a chemical plasticizing additive. It is obtained by processing calcium salts of lignosulfonic acids. The substance helps to increase the mobility of the concrete mix, entrain air in it and reduce the sticking of cement grains. Manufacturers may supply SDBs as solid or liquid concentrates. To achieve the protective effect of this additive, you need a little more than soap naphtha. In terms of dry matter of cement, it is necessary to introduce 0.15 - 0.3% of sulfite-yeast mash. It increases frost resistance by 1.5 - 2 times, by 5 - 10% strength, by one grade - water resistance, resistance to mineral salt solutions and crack resistance.

Sulfite-yeast mash has the best effect when it is introduced into a concrete stone based on high-aluminum and fast-hardening Portland cements.

Silicone liquid GKZH-94. This is a hydrophobic and gas-forming additive, which is formed during the hydrolysis of ethylhydrosiloxane. As a result of the interaction of cement and this additive, hydrogen is released and a large number of closed pores evenly distributed in concrete are formed. It has an active water-repellent effect on the capillaries and pore walls of concrete. It almost does not affect the rheological properties of the mixture, but it greatly slows down the process of concrete hardening (initial stages). Supplied as a 50% aqueous emulsion or 100% liquid. The second is introduced into the concrete mixture in the amount of 0.03 - 0.08%.

It helps to increase the water resistance of concrete by two grades, frost resistance - by three to four times. In addition, it increases resistance to variable moistening and drying, the effects of mineral salt solutions (under conditions of capillary suction), stretching.

Secondary protection of concrete against corrosion provides for the application of various paintwork materials, protective mixtures, coatings and lining with various plates. Those. concrete waterproofing.

Secondary protection can also include carbonization (exposure of concrete in air).

Corrosion protection of concrete with paint and acrylic coatings used when exposed to solid and gaseous media. The resulting protective film effectively protects the concrete surface not only from air and moisture, but also from the effects of various microorganisms.

Protecting concrete from corrosion with mastics it is used when exposed to moisture, contact with solid media. Mastics based on various resins (resinization) are often used.

Protection of concrete against corrosion by sealing impregnations used in almost all media (liquid, gaseous), especially when high humidity, in addition, they are used before applying paintwork materials. Sealing impregnations fill the outer layer of concrete, giving it good hydrophobic properties, and reduce water absorption.

Biocidal materials used to protect concrete from impact various kinds fungi, mold, bacteria, microorganisms. Chemically active substances of biocidal additives fill the pores of concrete and destroy bacteria.

Corrosion protection of concrete with adhesive coatings it is used in the operation of concrete stone in liquid media, soils with high humidity and places of frequent wetting with electrolyte. For example, the lower part of a concrete breakwater is pasted over with polyisobutylene plates.

As pasting coatings, polyethylene film, polyisobutylene plates, oil bitumen rolls can be used. They can also act as an impermeable sublayer in claddings.

The most effective is the complex protection of concrete against corrosion, i.e. both primary and secondary.

Aggressive environment negatively affects the condition building materials. Salt, carbon dioxide, water, and temperature fluctuations (freeze-thaw cycles) often lead to corrosion. Therefore, the protection of concrete from corrosion is the most important task in the construction or operation of any objects.

Causes of corrosion

Concrete produced on a mineral basis has a capillary-porous structure and is subject to the greatest impact in comparison with other materials. As a result of atmospheric action, crystals are formed in its porous structure, the increase of which leads to the appearance of cracks. Carbonates, sulfates and chlorides, dissolved in large quantities in the air, also have a devastating effect on building structures.

Types of corrosion

Corrosion of concrete is divided into three types. The main criterion for such a classification is the degree of deterioration of its characteristics and properties.

• First degree - washout constituent parts concrete.
• The second degree is the formation of corrosion products without binding properties.
• The third degree is the accumulation of poorly soluble crystallizing salts, which increase the volume.

Protection methods

To protect concrete and increase its durability, you should apply primary and secondary protection.

Primary protection methods include the introduction of various modifying additives. They can be plasticizing (increasing), stabilizing (preventing delamination), water-retaining, and also regulating the setting of concrete mixes, their density, porosity, etc.

Secondary protection methods include the application of various protective coatings:

• Biocidal materials - destroy and suppress fungal formations on concrete structures. The principle of operation is the penetration of chemically active elements into the structure of concrete, and their filling of microcracks and pores.
• Pasting coatings - are used when exposed to liquid media (for example, if a concrete pile is heated groundwater), in soils, and also as an impervious sublayer in facing coatings. These can be oil bitumen rolls, polyethylene film, polyisobutylene sheets, etc.
• Sealing impregnations - give concrete high hydrophobic properties, dramatically increase water resistance and reduce water absorption of the material. Due to these properties, they are used in conditions of high humidity and in places where there is a need to ensure special sanitary and hygienic requirements.
• Paintwork and acrylic coatings- form weatherproof, strong and durable protection. So, for example, acrylic prevents destruction by creating a polymer film. Another advantage of this method of combating corrosion is the protection of the surface from fungi and microorganisms.
• Paint and varnish mastic coatings - are used when exposed to liquid media, as well as in direct contact of concrete with a solid aggressive environment.

Anti-corrosion coatings can be applied wherever there is a similar need for concrete. Structures made of this material are found in the floors and walls of residential premises, foundations, garage complexes, greenhouses, greenhouses, treatment facilities, collectors. Also when choosing protective equipment you should take into account the characteristics of the environment, the possible physical and chemical effects.

Concrete corrosion inevitably, sooner or later, under the action of aggressive chemicals, it begins to destroy concrete and reinforced concrete products, structures. Let's try to figure out what is chemical corrosion of concrete and what is the protection of concrete from an aggressive environment. Corrosion is the process of destruction of concrete over a long period of time.
The consequences of concrete corrosion entail a decrease in the strength of structures, deterioration in performance and, of course, large material costs.
Therefore, the protection of concrete from corrosion is the most important task of construction and operation.

Protection of concrete against corrosion is carried out by chemical and polymeric impregnations for concrete, which provide resistance to chemical aggression, mechanical protection of the concrete surface.

To protect concrete from corrosion, we produce and offer a wide range of concrete impregnations.

The section Impregnation for concrete provides detailed information on technologies and prices, recommendations on the choice of impregnations.

It is necessary to distinguish between the operating conditions of structures: on air; in the ground (groundwater); under the water.

The type of operation will depend on the environment in which corrosion of concrete and reinforced concrete will proceed on its own. Accordingly, it depends on which impregnation for concrete should be used. Corrosion destroys not only the concrete itself, but also the reinforcement contained in it. Destruction can be both chemical, biological, and physical. The presence of an atmospheric-chemical factor makes concrete vulnerable to self-destruction, as there are processes associated with the impact on concrete of aggressive substances from the atmosphere - gas corrosion of concrete. Such as: chlorides, carbonates, sulfates; as well as ongoing freeze and thaw cycles. Corrosion resistance depends on the intensity of the aggressive environment, the contact conditions of the interaction, the pressure and speed of movement of liquid media, the action ground water. The intensity of the aggressiveness of the environment can be different for concretes with different densities, as well as for concretes made on different binders. What will cause corrosion in concretes made with Portland cement will not affect concretes made with Portland slag cement or aluminous cement. Corrosion problems arising in solid and gaseous media mainly proceed with the help of the liquid phase.

Types of concrete corrosion

There are many factors and conditions that influence corrosion on concrete. When choosing impregnations for concrete, it is necessary to take into account in what environments and under what conditions (temperature, humidity, etc.) the concrete surface will be used.
Consider the main types of chemical corrosion of concrete.

1. Acid corrosion of concrete is a consequence of exposure to organic and inorganic acids.
2. Sulfate corrosion of concrete - occurs as a result of interaction with sulfates.
3. Alkaline corrosion of concrete is a consequence of interaction with alkalis.

There are two types of aggressive impact of the environment on concrete. The first is the impact for liquid media and the second for gas.
The impact on concrete of the aquatic environment occurs in three cases:

1. Washing out of cement stone particles with soft water by filtering water through concrete.
2. Exposure to waters containing chemicals.
3. Accumulation of poorly soluble salts in the pores of concrete and their crystallization, followed by destruction.

Gas corrosion of concrete is mainly due to the content of carbon dioxide in the air.

Properly selected impregnation for concrete will provide long-term protection.

Corrosion of concrete and reinforced concrete can proceed for a long time, and has several degrees of aggressiveness.

Permissible depth (cm) of destruction of concrete for 50 years.

Corrosion protection of concrete

It is necessary to protect concrete from an aggressive environment - a coating or impregnation for concrete, which could ensure efficient and durable operation. Consider, as an example, the technology of concrete fluting. A simple and convenient technology for impregnating concrete with Elakor-MB1 fluorosilicate (fluate impregnation for concrete) makes it possible to apply it both for concrete that has just gained strength, and for concrete with a long service life. Fluorosilicate acts on active lime and converts it into chemically passive and mechanically strong calcium fluoride, which contributes to a significant increase in chemical resistance. In addition, under the influence of fluorosilicate, solid silicates are formed, which provides an increase in the strength of concrete. Fluorosilicate impregnation for concrete gives full protection from all negative environmental factors, providing improved performance.

Initially, the term "corrosion" was applied only to metals. Later it began to be used in relation to other materials and products from them. The main synonym for corrosion is destruction. And this process is subject to almost all building structures under the influence of various external factors.

In particular, concrete corrosion is the collapse of its structure, loss of density, strength and, as a result, loss of performance. The destruction of concrete elements begins with the scattering or delamination of the cement stone, since the aggregates are more resistant to aggressive influences.

Types of concrete corrosion

Precipitation containing acids and even air in the vicinity of many industrial enterprises (gas corrosion) can have a harmful, destructive effect on concrete. As well as water from rivers, seas, soil, drainage systems and stocks. When the structure is made of reinforced concrete, then the risk of corrosion processes in the reinforcement is added to external factors.

Depending on the nature of the impurities contained in the external environment, the corrosion of concrete and reinforced concrete is divided into three types:

• 1st type of corrosion - decomposition of cement stone as a result of leaching of calcium hydroxide. This element may be present in the concrete mixture from the moment of its formation, or be formed in the process of exposure to the finished structure of water with harmful impurities. Ca (OH) 2 is the component that dissolves most easily and is most quickly washed out of the concrete body, thereby destroying it.
• Type 2 - implies the disintegration of cement stone from interaction with acids. This type is called chemical corrosion. In this case, easily soluble lime products are washed out in the structure, or the opposite process occurs. Under the influence of aggressive waters, precipitation is formed in the concrete body that does not have astringent properties. As a result, the product loses its strength and turns into a weak loose mass. Alkaline corrosion can be included in this category, which is caused by an excess of antifreeze additives during the formation of the concrete mixture.
• Type 3 corrosion is a process in which, under the influence of an acid, a calcium compound is formed that is insoluble in water. CaCO 2 or CaSO 4 gradually fills the free pores in the mass of concrete, increasing its volume, which results in the destruction of the structure. Of all the types of category 3, sulfate corrosion is the most common in practice.

It is clear that such a division is conditional, since it is not always possible to determine with great accuracy what exactly affected the erosion of a particular structure.

Corrosion processes usually occur under the influence of a combination of various factors and several categories of destruction can occur simultaneously.

In particular, the absence or presence of corrosion of reinforcement in reinforced concrete has a significant impact on the integrity of the structure.

What leads to rusting of the reinforcing cage

There are several reasons for the appearance of rust on the metal inside the concrete mass. And it is not always external influences.

• Internal corrosion can be caused by a large number aggressive components in the water used to mix the concrete mix. In addition, to create reinforced concrete, you cannot use a composition containing more than 2% (by weight of cement) calcium chloride. Since this element significantly accelerates the corrosion of reinforcement in concrete during operation in any environment.
• Equally important is the density of the concrete mix. The fact is that the presence of a large number of pores, voids, shells makes it possible for moisture and air to penetrate inside the product, to the reinforcing cage. As a result, different electrical potentials arise in different parts of the metal circuit, which leads to electrochemical corrosion.
• The concept of physical corrosion is associated with the destruction of concrete as a result of its alternate freezing and thawing. This trouble can be avoided by creating favorable conditions during the curing of concrete strength to a given value.

In order to correctly assess the situation and take corrective action, it is necessary to understand the level of threat. To determine the degree of corrosion of reinforcement and concrete, physico-chemical methods are used:

• The study of the composition of the components newly formed in the concrete mass under the influence of aggressive substances. Research is carried out in the laboratory using differential thermal and X-ray structural diagnostics on specially selected samples.
• Conducting a visual inspection of the modified structure of the concrete in the structure, using a magnifying loupe. This method allows to reveal many surface defects.
• Powerful microscopes help to detect the nature of the location and connection of cement stone elements with grains of aggregates. As well as the state of contact of concrete with reinforcement, dimensions and direction of crack propagation.

To determine the strength characteristics of operated structures made of concrete and reinforced concrete, non-destructive testing methods are used in accordance with the recommendations and requirements of GOST 18105-86.

How to protect concrete from corrosion

Concrete and iron protection methods concrete structures from destruction due to rust can be divided into the following options:

• Correct the composition of the concrete mix in such a way as to increase its strength characteristics, as well as resistance to the harmful effects of operating conditions. This can be achieved by using special additives or a binder with special properties. For example, belite cement, which reduces the degree of formation of calcium hydroxide.
• Use means to protect reinforcement in concrete from corrosion during the formation of the steel frame.
• Treat the outer surfaces of the structures with hydraulic mixtures.
• Use measures to cover concrete with anti-corrosion preparations that have the property of deep penetration into the body of the product.

There are many reasons for the formation of corrosion of reinforced concrete, and protective measures also vary. They are divided into primary and secondary. The first includes measures to give the concrete mix improved characteristics. Additives are used that have a stabilizing, waterproofing effect, as well as plasticizers, biocides and much more. These include:

• sulfate-yeast mash;
• organosilicon preparation;
• soap-naft.

The secondary protection of concrete against corrosion is provided by the external coating of concrete structures with paints and varnishes, mastic materials, or impregnations with sealing properties.

A good result is given by a waterproofing pasting coating. However, the best effect can be achieved by using primary and secondary protection in combination.

Corrosion in any of its manifestations is dangerous for buildings made of concrete and reinforced concrete. Therefore, it is very important to comply with the rules and regulations for the construction of buildings and structures. Apply the necessary protective measures to prevent rusting of structures.

Providing excellent manufacturing technology, maintaining the exact proportions of the composition, using quality components and flawless laying does not yet determine that you will get concrete that is perfect in every sense. Young concrete up to two weeks, like a child, requires careful care and protection, protection from the action of aggressive environments.

Factors affecting concrete

Concrete is protected not only from weather phenomena, but also from artificial processes that accompany construction work. Of course, the main "enemies" of freshly poured concrete are temperature (both low and too high) and excessive moisture, or rather systematic or long-term direct contact with water. To gain strength with a solution, any mechanical effects are dangerous. For example, when moistening the mixture, in no case should this be done with a jet of water, this will cause deformation and blurring of the upper layer. To prevent such situations, there is a whole range of measures to protect concrete from exposure.

Primary concrete protection

Primary protection is the introduction of special additives and fillers into the composition of the concrete mix, preventing or reducing the impact of aggressive environments on the composition in the future. This protection is made even before pouring, so it is important to predict and calculate possible problems for concrete curing at the design stage.

This group also includes the selection of the optimal shape and geometry of the structure, which is also done in advance. Primary protection includes the use different kind compactors, vibrorammers to reduce the number of pores in the mixture.

Secondary concrete protection

Secondary protection methods themselves are more complicated in organization and design, but no less effective, especially if used along with primary ones. The main task is to localize concrete or isolate it from the external environment. This is achieved by installing additional layers, mainly waterproofing.

Protection of concrete after pouring includes such obvious measures as covering it with films, canopies from exposure to the sun and moisture, to keep warm in case of low temperatures. Heating and maintaining optimal humidity are also a measure of protection and are provided by electrical appliances. Spraying moisture with the use of protective components on the surface of the concrete protects it from the rapid evaporation of moisture.

Protection of concrete after laying and pouring

There are several ways to protect already laid concrete from the influence of the environment:

• special material impregnation
• painting
• protection with polyurethane compounds (varnishes)

The first method is more expensive, but more reliable due to the action not only on the surface, but also on the entire thickness of the concrete, providing waterproofing properties. Very effective protection of concrete with polyurethane compositions of ready-made concrete structures (hardened), often used for concrete floors. We should not forget about the technology of re-filling in order to avoid "cold seams". As a result of temperature differences or staged pouring, such joints can cause water to penetrate into them and destroy the overall concrete mass. Corrosion protection of concrete structures is also important and is carried out both at the stage of preparing the mixture when adding anti-corrosion additives, when compacting and vibrating the mixture, and by coating ready-made concrete with water repellents.

Concrete protection and care have special provisions in SNiP and design solutions for construction projects, compliance with them will help you not only get the long-awaited result within the estimated time frame, but also save decent amounts and time without correcting mistakes.