What is concrete corrosion

Why does concrete corrosion occur and how to deal with it?

• Types of concrete corrosion
• What is concrete corrosion?
• Corrosion processes in reinforced concrete
• How can concrete and reinforced concrete be protected against corrosion?
• Types of concrete protection against corrosion

When manufactured according to all the rules, corrosion of concrete is not dangerous for products made from it, and they will serve for a very long time. Concrete must be resistant to the corrosive effects of cement stone.

Concrete corrosion is the process of destruction of the integrity of the material resulting from the influence of external aggressors.

Currently, concrete remains one of the most popular materials in the construction industry. The properties of this material are mostly positive and resistant to atmospheric influences.

Types of concrete corrosion

The physical and chemical effects of the surrounding space on concrete are such that it is destroyed, called corrosion. Many processes occur in the connection between cement and water, an aggressive environment arises, and to protect concrete from corrosion, it is necessary to study the intricacies of this phenomenon. Experts distinguish 3 types of corrosion, but most often destruction occurs under the influence of several types at once:

Types of concrete destruction.

1. Biological corrosion of concrete, implying the formation of large-volume compounds in the concrete stone. This occurs under the influence of various substances that penetrate into concrete. Connections that acquire greater volume inside cause internal stresses and, as a result, cracks in the concrete. Sulfate corrosion is of greatest importance in the study of concrete destruction.
2. Physico-chemical forms of concrete corrosion, in which the components of concrete stone dissolve in water. In this case, the dissolution and leaching of calcium hydroxide that was previously present or formed often occurs. Reinforced concrete is eroded by water at different rates. Hydraulic structures have a dense mass in which corrosion occurs slowly, its results are visible only after decades. And in cooling towers that have thin shells, calcium hydroxide is washed out much faster, which is why repairs are required after just a few years. If water is filtered through concrete, decomposition is accelerated many times over, the concrete becomes highly porous, and its strength is reduced by more than half. This process is also called lime leaching or white death, due to the external signs of such destruction. When the material begins to be corroded by an aggressive environment, it becomes covered with a white coating.
3. Chemical corrosion, which occurs as a result of the interaction of concrete stone and substances from the environment, often forms easily soluble salts, which are then washed out. Together with substances washed out by water, amorphous masses that have no binding ability are often deposited in concrete masses. Under the influence of these forces, concrete over time turns into a loose porous mass, which collapses very easily.

Corrosion can be called a separate branch of science, which studies all processes called corrosion, means of preventing them, and the resistance of concrete structures to various natural processes. Such a phrase as concrete corrosion sounds unusual, but not only concrete, but also brick, asbestos cement and aerated concrete, foam concrete along with silicate blocks corrode.

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What is concrete corrosion?

Scheme of concrete corrosion.

This process begins with the concrete hardening, turning into cement stone, the durability of which is much lower than that of stone fillers. The composition of cement stone includes compounds formed during the hardening process. It has many capillary passages, both open and closed, they can be filled with either water or air. The structure of hardened concrete is very heterogeneous.

In relation to hardened concrete and reinforced concrete, river water, sea water, sewage and drainage water, together with acid gases present in the air, are aggressive. Within cities and especially in areas of industrial enterprises, groundwater contains a lot of different impurities that contribute to the corrosion of hardened reinforced concrete.

If there are chemical plants in the vicinity, then groundwater will be contaminated with acids, both organic and mineral, nitrates and chlorides, ammonium, copper, zinc, iron and nickel salts, sulfates, and alkalis.

In the vicinity of metalworking plants, the soil will be saturated with the products of pickling processes and iron sulfates.

Dependence of the rate of destruction of concrete on the time of exposure to unfavorable factors.

More than groundwater, wastewater from factories and factories is saturated with substances that cause the destruction of cement stone. If untreated water is discharged into rivers, then the water in the rivers becomes aggressive towards concrete structures.

Concrete corrosion very often affects hydraulic structures. The air near and at the enterprises themselves also often contains pollutants, such as nitrogen oxides, sulfur dioxide, and hydrogen chloride.

The concentration of these gases within the permitted standards does not cause harm to human health, but nevertheless it is enough for concrete structures to begin to collapse.

Corrosion of concrete is very diverse, since there are more than a hundred substances and their compounds that, when in contact with concrete stone, cause its destruction. There are microorganisms called biodestructors that destroy all types of structures.

Microorganisms that destroy materials can be in direct contact with them or settle inside porous structures. The worst time for concrete structures is the metabolic processes of microorganisms, since all the qualities of the material and its service life are significantly reduced.

Bioorganisms that produce substances aggressive to concrete are capable of harming concrete even from a distance.

In any liquid or gaseous medium, corrosion of concrete and reinforced concrete does not require additional factors. If there is high humidity in a gaseous environment, this factor accelerates corrosion processes.

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Corrosion processes in reinforced concrete

Reinforced concrete is most susceptible to corrosion, as it contains a metal frame.

Although the processes occurring in these materials are very similar, the destruction of reinforced concrete is a much more complex process. The difficulty lies in maintaining a metal frame, for which electrochemical corrosion is the enemy. Reinforced concrete is considered to be very strong and durable.

This is due to the formation of a passive layer with protective properties during the interaction of the surface of the reinforcement and the alkaline nature of concrete. But at the same time, if concrete is exposed to precipitation containing salts and carbon dioxide for a long time, carbonization occurs, and the environment as a result becomes acidic.

As a result, the strength decreases and the building begins to collapse faster.

In order for this type of corrosion to be stopped, it is necessary to introduce special inhibitors into concrete that act specifically on metal corrosion. Such substances can create a film on the surface of the reinforcement inside the concrete, which increases the overall strength.

This film does not allow metal and concrete to interact, thus the electrochemical corrosion reaction does not occur. These compounds are added directly to the raw solution before making concrete slabs or applied to finished products.

The composition can penetrate 50 mm into concrete.

The process of corrosion destruction is complex and dangerous for reinforced concrete buildings. If you don't take it seriously enough and don't try to prevent and stop its effect, any structure will be destroyed much faster. Projector anodes are also used to protect reinforced concrete.

With their help, an electrical contact is created between a frame made of reinforcement and a metal blank, which has more active properties. With electrochemical corrosion, decomposition occurs due to the EMF of the metal with negative values.

Until the more reactive metal dissolves, the reinforced concrete frame will be out of danger.

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How can concrete and reinforced concrete be protected against corrosion?

Methods for protecting concrete from corrosion.

Concrete, widely used in construction, has several developments that are used to combat and reduce destructive processes. This includes both protecting the material from environmental influences and introducing various types of additives that have different functions. Some of them prevent cracks from appearing in concrete, its destruction and washing out. High-density concrete, which has no capillary structure inside, is often used for structures.

The destruction of concrete can be stopped by introducing hydraulic additives. To prevent leaching, they bind calcium hydroxide into a compound that is less susceptible to dissolution, calcium hydrosilicate.

Protection of concrete from corrosion may involve the use of belite cement, since this material releases minimal calcium hydroxide and contains less tricalcium silicate.

If the destructive liquid is in small quantities and evaporates from the concrete surface on its own, calcium hydroxide will not be washed out of the concrete. It will compact its structure and stop filtration, which is called self-healing of concrete.

If cement stone is damaged by waters that contain sulfate or chloride salts, this is due to the formation of products, which are then easily washed out of the concrete. It happens that the binding properties of concrete are lost. This must be dealt with in a similar way by reducing the calcium hydroxide content in concrete. For example, calcium chloride is 100 times less susceptible to dissolution in water when compared with calcium hydroxide.

Major repairs, waterproofing and protection of concrete structures from corrosion.

Corrosion of sulphate concrete is characterized by formations in the pores of concrete, which rupture it during growth. These are called cement bacilli. Therefore, cement whose tricalcium aluminate content is insufficient must additionally be resistant to sulfates. Concrete structures should not be covered with fungi and bacteria, river and sea algae, lichens, mosses, and plants, as all this has a destructive effect on them.

Protection of concrete from water with various additives can be done in various ways. These could be improvements, technological changes, including stages of concrete preparation. Cement for preparation must contain active mineral additives of a certain type and an appropriate mineral composition. Solutions that use drainage, drainage and waterproofing to protect concrete from corrosion can also help.

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Types of concrete protection against corrosion

The simplest way to protect concrete structures from corrosion is painting.

Good corrosion resistance of concrete is to compact it as much as possible during laying and special preparation of mixtures. To do this, you will need to prepare mixtures with a minimum water-cement ratio. Water resistance can be increased by using various types of additives, such as granulated blast furnace slag, flask, diatomite, tripoli.

Thus, concrete protection can be divided into 2 types. Primary protection is considered to be the addition of various kinds of substances during creation, and secondary protection is the application of protective coatings to finished concrete structures. This protection includes sealing impregnations and paint coatings.

Painting concrete walls is very popular. If the paint contains polyvinyl chloride resin, then after some time after hardening the paint forms a good protective film. This type of technology is successfully applied to residential buildings and private houses, to public buildings.

Decorative items and façade slabs can be protected in the same way.

To make the protection even more reliable, biocidal preparations are used, which reduce the biological impact on concrete, and sheet protective materials.

Such preparations penetrate very deeply into the structure of concrete, protecting it both inside and not just outside. Penetration into depth contributes to a significant reduction in water permeability. Usually, inside the concrete, the preparations create a crystalline structure that does not allow moisture to enter. Thus, the moisture content of the concrete remains at a level at which the corrosion process does not begin.

Source: https://VseBloki.ru/stati/pochemu-poyavlyaetsya-korroziya-betona-i-kak-s-ney-spravitsya/

Chemical Corrosion of Concrete. Reasons and measures to protect concrete from corrosion on Roof-n-Roll,ru

Concrete is a composite material often used in construction. The final properties of concrete depend on many different factors: composition, quality of initial components, preparation technology, etc.

The main advantages of concrete are its strength and durability, as well as the ability to form products of any shape while protecting the reinforcing steel.

Protection of reinforcement in concrete is determined by the high alkalinity of concrete (pH 12-13.5). In such a highly alkaline environment, such as concrete, a protective layer (passivation layer) is formed on the surface of the steel reinforcement, which reliably protects it from corrosion of the reinforcement in concrete.

But concrete , just like any other materials, is subject to aging and its corrosion processes . Various environmental factors, combined with frequent design or construction errors, lead to the destruction of the concrete structure.

Corrosion of concrete and reinforcement gradually leads to their destruction and loss of the bearing capacity of the entire structure. Depending on the causes, concrete corrosion can be physical or chemical .

Physical corrosion of concrete.

Physical corrosion of concrete is caused by:

• The destructive effect of frost on wet concrete (while retaining residual moisture in the concrete body and with a sharp drop in temperature, water freezes forming ice crystals, which ultimately leads to a significant loss of strength and deformation of the molecular bonds of the concrete structure. Therefore, all work related to “wet” processes should be carried out at ambient temperatures above +5 degrees or when creating “warmhouses”).
• Abrasive wear of a concrete structure
• Mechanical damage to the concrete structure
• The destructive effects of variable or dynamic loads , as well as the effects of excessive loads on a concrete structure.

Chemical corrosion of concrete.

The cause of chemical corrosion of concrete is the chemical action of liquid or gaseous substances with concrete components, which will lead to its destruction.

For example, carbon dioxide contained in the air in combination with moisture will start the process of concrete carbonization . As a result of chemical reactions in concrete during the carbonization process, calcium carbonate is formed, which, on the one hand, compacts its structure, increases resistance to leaching and increases compressive strength, but on the other hand, leads to its neutralization or decrease in alkalinity, which reduces the protection of steel fittings.

Rainwater with a low salt content washes soluble calcium compounds from the concrete structure , forming white stains (efflorescence) on the surface.

This leads to an increase in the porosity of concrete and a decrease in its strength , and, as a result, the carbonization process begins to occur faster, and corrosion of the reinforcement begins earlier.

Chemical corrosion of concrete , as a rule, is characteristic of all old concrete structures.

However, damage to concrete structures caused by one reason or another can be eliminated by restoring both the protection of the reinforcement frame and the directly destroyed concrete body. These measures can significantly extend the service life of the structure.

Note that the process of gradual aging of concrete structures should be perceived as normal , as well as the process of carrying out repair work to restore and protect them. The main thing is to follow technologies and materials in such a way that the turnaround period is as long as possible.

Ceresit specialists have developed a system of materials for the restoration and comprehensive protection of concrete and reinforced concrete structures, which is suitable for Russian conditions, compatible with concrete class not lower than B22.5 (M300 and higher), has excellent performance properties and provides significant time savings between applying different layers using the wet-on-wet method.

Components of the Ceresit system for repairing and protecting concrete

Price list: waterproofing and concrete repair Ceresit prices

Source: https://www.roof-n-roll.ru/services/sukhie-smesi/biblioteka-tekhnologa/korroziya-betona-prichiny/

How to prevent concrete corrosion and protect the material from destruction?

Concrete is a material that is essential for the construction of residential and non-residential buildings. Its structure is very durable, but even this building material deteriorates and collapses over time.

With constant contact with water, as well as as a result of exposure to temperature changes, cracks and other defects appear on the surface.

But corrosion of concrete will not be so dangerous if the requirements of regulatory documentation are taken into account when manufacturing and maintaining reinforced concrete products.

Types of corrosion and causes

Concrete that is located on the street is constantly exposed to negative environmental influences. Precipitation, temperature fluctuations, acids and gases - all this causes certain physical and chemical reactions in the structure of the material. Based on the research, the types of concrete corrosion, as well as the main causes of its occurrence, were identified.

Biological

This type of change in concrete and reinforced concrete occurs as a result of the accumulation of salts in microcracks and capillaries of the structure, which are insoluble in water. Gradually, a hard stone forms, which provokes the destruction of concrete. It is possible that bacteria, fungi and algae can penetrate into the pores of the material, which continue to multiply and provoke cracking of the structure.

Physico-chemical

This is the process of leaching important components from the body material. The structures are mainly used in open areas, so they are affected by external negative factors. The concrete mixture contains calcium hydroxide, which evaporates when exposed to a humid environment or water. Under the influence of this influence, the structure of concrete is disrupted, and cracks begin to appear, provoking processes of further destruction.

Chemical

Chemical corrosion of concrete is the process of washing away lime formed by easily soluble compounds in direct contact with an acidic environment. Under the influence of aggressive environments, the formation of salts and amorphous masses occurs. The former are formed in the process of interaction with negative factors; they quickly dissolve and are washed out along with water. Amorphous masses have no binding characteristics at all.

Chemical corrosion is recognized as a result of the appearance of hydroferites, hydroaluminates and hydrosilicates, which contribute to the formation of soluble salts and other substances. carbon dioxide provokes the appearance of corrosion of carbon dioxide-type concrete structures. The reason for the destruction of the oxide film formed by carbonate is the excess of the permissible carbon dioxide content.

To ensure the protection of reinforced concrete structures and concrete, it is necessary to study the cause of the occurrence of adverse factors and take this into account during manufacturing, installation work and when caring for concrete.

Corrosion from destruction of reinforcement

Reinforced concrete products consist of two components - a concrete mixture and reinforcement. The latter has a direct effect on the material. During operation, the metal rusts because concrete is exposed to chemical elements: chlorine, hydrogen sulfide and sulfur dioxide gases. Internal stress appears in the body of the concrete structure, which leads to the formation of cracks.

Air and water penetrate inside through the pores of the concrete product. Electrochemical corrosion occurs due to uneven exposure to negative environments, and the rate of reactions depends on the level of moisture penetration and the pore size of the stone.

If concrete is left in the open air for a very long time, then under the influence of carbon dioxide a thin layer of oxide film will form, which does not dissolve in water and does not react with salts. The name of the process is carbonization. It protects the concrete stone from rust, but causes corrosion of the reinforcement.

When manufacturing reinforced concrete products, anti-corrosion treatment of reinforcement should be taken into account. These requirements are mandatory and regulated by regulatory documents.

Methods for protecting concrete

In order for the material to be affected as little as possible by corrosion throughout the entire operation of reinforced concrete products, which results in its destruction, the design process must provide for conditions to prevent these phenomena.

Protection measures typically include sealing, neutralization and ventilation while the concrete products are performing their intended purpose.

It is important to ensure that in the process of constructing forms of concrete and reinforced concrete products there are no places for water concentration, that is, there must be natural drainage of the formed surface. The latter is achieved by forming a slope of the concrete base during the construction of the structure. In general, they protect concrete from corrosion in two ways: primary and secondary.

Primary protection

At the manufacturing stage, various additives are added to the concrete mixture, so the mineralogical composition of the final material changes. The effectiveness of this method has been confirmed by tests.

Anti-corrosion additives for concrete mixtures can be plasticizers, water-retaining compounds, or the addition of chemicals, including amorphous silica.

The manufacturing project takes into account the operating environment of the product; for example, if contact with sulfate-containing water cannot be avoided, then the percentage of sulfur dioxide in the concrete mixture must be reduced. Quite often pozzolanization is used, that is, hydraulic additives with active silica are added to the composition of Portland cement. In this case, calcium hydrosilicate is formed, which is more resistant to corrosion than calcium hydroxide.

When a chemical active additive is added to a concrete mixture, the density of the concrete stone increases, and this helps slow down the rate of exposure to aggressive environments. As a result, the fittings inside are less susceptible to rust.

Additives make it possible to reduce the size and number of pores, and this ensures an increase in the resistance of the future structure to frost.

Anti-corrosion additives

Protection of concrete from corrosion must be ensured at the stage of production of the mixture and reinforced concrete structures. Chemical additives against the effects of the corrosive factor are as follows:

• plasticizers;
• anti-frost;
• air-entraining;
• sealing;
• corrosion inhibitory properties;
• gas-forming;
• reducing the setting speed.

From this list we can highlight several of the most commonly used types of anti-corrosion mixtures:

Additive name	Compound	Properties	What part should be added?
Mylonaft	A mixture of organic acids and sodium salts, insoluble in aqueous media.	Increasing the homogeneity of concrete, reducing the coefficient of friction between components, involving air masses. Frost resistance and water resistance increases by 2 levels, as a result of which the resistance to cracking and penetration of mineral salts increases.	0.15-0.5% of the bulk of the cement powder; if the dosage is exceeded, the strength of the sample during compression testing decreases.
Sulphite-yeast mash or SDB	This additive is produced by processing calcium salts from lignosulfonic acids.	The mobility of the concrete mixture is significantly increased, providing better adhesion of cement powder grains and penetration of air masses. Hydrogen is released and pores are formed. Resistance to frost increases almost 2 times, and the strength index increases from 5 to 10%. Water resistance, salt resistance and crack resistance increases by one grade.	It is enough to introduce 0.15-0.3% SDB into concrete. Available in solid or liquid form.
GKZh -94	The production of the product is achieved through the hydrolysis process of ethylgyrosiloxane.	When cement and this additive come into contact, hydrogen is released, so many pores are formed, which are simultaneously closed to each other. The capillaries and walls of concrete are actively affected by a water-repellent substance. The process of setting the mixture slows down. At the same time, water resistance increases by 2 levels, and frost resistance by 3-4 times.	0.03-0.08% of this substance is introduced into concrete. Available in liquid form, 100% composition or 50% solution with water.

Important! The percentage of added additives is established by regulatory documents and taken into account by the manufacturer during manufacturing.

Source: https://GidPoKraske.ru/spetsialnye-materialy/rzhavlenie/korroziya-betona.html

Concrete corrosion, its types and methods of combating corrosion

Concrete is a fairly popular building material. It is a combination in certain proportions of such constituent elements as cement, sand, water, crushed stone. The binding element is cement, which hardens to form concrete.

What is concrete corrosion

Concrete corrosion is a process that leads to the destruction of the integrity of the structure of the building material. Corrosion can occur as a result of several factors, for example:

• Effect of moisture and water on concrete
• Periodic freezing and thawing of material
• The process of saturation with moisture and drying, which is repeated cyclically
• The action of various substances, the result of which is the destruction of concrete

There are several types of concrete corrosion, each of which depends on the action of certain factors.

Types of corrosion

Based on the results of experiments and research conducted by scientists, the main types of concrete corrosion were identified http://udarnik.spb.ru/produkty_i_uslugi/korroziya_betona/:

• Washing out of the constituent elements of a building material - the main cause of this type of corrosion is the leaching of the main elements from its composition. For example, when water or moisture gets on cement, calcium hydroxide is washed out of it, and as a result of a chemical reaction, hydrosilicate, hydroaluminate and calcium hydroferrite are destroyed. These processes increase the porous structure of the material, thus destroying its integrity
• Exposure of cement to materials that have an aggressive reaction - the main factors that lead to the occurrence of this type of corrosion are aggressive substances, the effect of which on cement leads to the formation of salts and amorphous masses. Depending on the type of aggressive substance, this type of corrosion is divided into subtypes (acid and carbon dioxide)
• The effect of microorganisms and their metabolic products on concrete - this type of destruction of the integrity of the concrete structure is called biocorrosion. The main reason for its development is fungi, microorganisms and algae that get into the porous compounds of the building material. As a result of the deposition of the products of their metabolism, concrete deteriorates slowly

Typically, the process of destruction of the integrity of concrete includes several types of corrosion of the material. That is why, when choosing methods of protection against corrosion, it is necessary to include a whole range of protective measures and measures that will help prevent the occurrence and development of concrete corrosion.

Source: https://nvph.ru/korroziya-betona

What is concrete corrosion and its causes?

There are three types of concrete corrosion found in nature. To increase the resistance of Portland cement in mineralized (sulfate) waters and for economic reasons, active silica (pozzolans) in the form of tripolite, trace, etc. or granulated blast furnace slag is introduced into it during grinding.

Three types of concrete corrosion

It was assumed that in this case the active silica of the additive would bind the free lime of the cement into a more stable monocalcium hydrosilicate:
SiO2 + Ca(OH) - CaO • Si02 • H2O.

However, it turned out that this reaction, which proceeds intensively at elevated temperatures, proceeds extremely slowly without heating (months and even years), and the additives achieve their goal only with high silica activity.

Granulated blast furnace slags, which are introduced into Portland cement in an amount of 30-70% of the total composition, act similarly. The acid resistance of these cements remains as low as without additives, and the sulfate resistance of pozzolanic Portland cements (in the presence of 30-40% of active additives) slightly increases. The alkali resistance of these cements is lower than that of Portland cements.

Considering in general the destructive processes occurring in cement concrete, they can be systematized based on the mechanism of transfer of active agents, according to the classification proposed by V. M. Moskvin:

1. Type I corrosion, in which relatively easily soluble components, mainly lime and alkalis, are removed or leached from concrete;
2. type II corrosion, when exchange reactions occur: this includes the action of acids, alkalis and some salts;
3. type III corrosion, which is observed when salts, especially sulfates, are introduced into concrete and accumulate there; the internal pressure developed in this case seems to explode the concrete with the formation of characteristic cracks.

Under specific conditions, one type of concrete corrosion may overlap or accompany another.

Salts and solutions hazardous to cement

Hardening cement concrete or mortar can be affected by various liquids and gases. Some of them reduce the strength, damage or even completely destroy Portland cement. Corrosion is associated with the release of free calcium hydroxide during cement hardening and the presence of tricalcium aluminate in it. As mentioned above, during the hydrolysis of cement, the following reaction occurs with the release of calcium hydroxide:

3CaO • Si02+-nH2O=2Ca0 • Si02(n-1)H2O+Ca(OH)2.

The simplest type of physical corrosion and the dissolution and leaching of free calcium hydroxide from cement. Although its solubility is low (at 15, about 1.3 g of CaO per 1 liter of water dissolves), a large amount of Ca(OH)2 can be washed out of the cement stone in concrete under the influence of running water; in this case, the cement stone becomes porous and loses some of its strength.

If the concrete is dense and has no voids or cracks, then corrosion can only occur from the surface; If the concrete is porous and water passes through it under pressure, then the process of washing out Ca(OH)2 is very intense.

The strongest dissolving effect on calcium hydroxide is exerted by pure distilled condensation water (in factories) and soft natural water.
However, dissolution is prevented by a protective crust of calcium carbonate, calcium hydroxide released in cement, and carbon dioxide during preliminary hardening of concrete in air: Ca(OH)2+CO2=CaCO3+H2O.

The solubility of calcium carbonate in pure water is approximately 100 times less than that of calcium oxide hydrate. The calcium carbonate crust, although very thin (usually only a few millimeters thick), protects the cement stone from dissolution (unless there is mechanical damage)

The protective properties of calcium carbonate are used, for example, in the construction of offshore structures from large concrete blocks. These blocks are prepared on the shore, kept in the air for 2-3 months to form a protective crust, and only then lowered into the sea.

Chemical corrosion of concrete

Chemical corrosion of cement occurs under the influence of acids, solutions of certain roles and other substances that react with calcium hydroxide released by cement or tricalcium aluminate of cement.

As a result, salts are formed that easily dissolve in water or, crystallizing in the pores and increasing in volume, tear the cement stone.
All acids, both inorganic (sulfuric, hydrochloric, nitric, etc.

), and organic (for example, fatty acids contained in vegetable and animal oils), have a destructive effect on ordinary Portland cement.

For example, when sulfuric acid acts on calcium hydroxide released during hardening of cement, gypsum is formed according to the reaction:

Ca(OH)2+H2SO4=CaSO4•2HaO

Gypsum crystallizes in the pores of the cement stone, and crystal growth destroys it. With tricalcium aluminate of cement, gypsum forms a complex substance, calcium hydrosulfoaluminate, which significantly increases in volume. All these phenomena lead to the destruction of cement stone by sulfuric acid.

When exposed to hydrochloric acid, calcium chloride is formed according to the reaction:

Ca(OH)2 + 2HCl = CaCl2 + 2H2O,
but calcium chloride is easily soluble in water, as a result of which the cement disintegrates.

Free acids are found in wastewater from industrial enterprises (they can penetrate into the soil and thus destroy concrete foundations) and in swamp waters; acid is also formed by sulfur dioxide gas coming out of boiler furnaces and steam generators of chemical apparatuses. When combined with air moisture or water vapor, sulfuric acid can cause corrosion of reinforced concrete floors: in factories, locomotive depots, etc.

Of the salt solutions, the most dangerous are sulfuric acid salts (sulfates). Natural waters, in particular sea waters, most often contain MgSO4 and CaSO4, sometimes Na2SO4, and industrial waters may also contain other sulfates

The effect of pure gypsum solutions on cement is the formation of a complex chemical compound between gypsum and tricalcium aluminate contained in cement, namely calcium hydrosulfoaluminate according to the reaction:

3CaSO4+3CaO • AlO3+water =3CaO • Al2O3 • 3CaSO4 • 31HaO.

This substance is formed with the addition of a large amount of water and increases in volume up to 2.5 times. Due to the expansion of this compound in the pores of the cement stone, it cracks, and then, under the influence of water or salt solutions, it turns into a white slime that flows out of the concrete.

Calcium hydrosulfoaluminate crystallizes in the form of thin needles resembling bacilli, which is why it is also given the figurative name “cement bacillus.”
Magnesium sulfate acts on calcium hydroxide released by cement due to the exchange reaction:

Ca(OH)2 + MgSO4 + 2H2O = Mg(OH)2 + CaSO4•2H2O;

the resulting magnesium oxide hydrate is a loose amorphous substance that lacks cohesion and strength, and gypsum crystallizes with an increase in volume or forms calcium hydrosulfoaluminate.

All these phenomena, as well as the dissolution of calcium hydroxide described above, lead to the destruction of cement stone and the release of a white dough-like mass from the concrete. This is where the expression white death of concrete comes from.

Of the chloride salts (chlorides), magnesium chloride (found, for example, in sea water), aluminum chloride, etc., have a destructive effect on cement.

When magnesium chloride acts on calcium hydroxide, easily soluble calcium chloride and loose magnesium oxide hydrate are formed according to the reaction: Ca(OH),+MgCl2=CaCl2+ Mg(OH2)

Table salt NaCl increases the solubility of calcium hydroxide, combines with aluminates and slightly reduces the strength of cement; therefore, the presence of a large amount of NaCl in the water acting on concrete is undesirable, but still NaCl is not dangerous for cement.

Of the nitrate salts (nitrates), ammonium nitrate NH4NO3 is very dangerous for cement.

Sea water, as well as water from salt lakes, estuaries and some groundwater containing MgSO4, MgCl2 and other salts have a destructive effect on ordinary Portland cement. If you do not take special protective measures, then in such water this cement will slowly deteriorate.

Natural waters usually still contain free carbon dioxide and its salts carbonate CaCO3 and calcium bicarbonate Ca(HCO3)2. These salts are not dangerous for cement, but free (aggressive) carbon dioxide in amounts greater than 15-20 mg/l acts in the same way as all acids, i.e. destructive. The following happens: the carbonate initially formed in the surface layer of concrete transforms into bicarbonate by the reaction:

CaCO3 + CO2 + H2O = Ca.(HCO3) 2.

Bicarbonate is easily soluble and washes out with water.
If it is necessary to supply water rich in carbon dioxide through concrete pipes, trays, into swimming pools, etc., then it is first passed through a filter filled with pieces of limestone, which binds aggressive carbon dioxide into bicarbonate. The limestone in the filter must be changed periodically.

Effect of sugar solution on concrete

A sugar solution has a harmful effect on concrete because it forms easily soluble calcium sucrose with calcium hydroxide. The effect of all of the listed waters, acids and salt solutions on cement is especially intense if the concrete is not dense, has not hardened enough, or if filtration through it occurs under pressure.

Silica salts (silicates) are harmless to cement, since cement itself consists mainly of silicates as well as salts of hydrofluorosilicic acid (fluates) and salts of carbonic acid (carbonates), for example soda.

Lime solutions

Solutions of sodium hydroxide lime and other alkalis, since hardened cement contains free calcium hydroxide and is therefore itself a basic compound. Ammonia and ammonia water are harmless to cement, but the presence of ammonia salts in water makes it dangerous.

Cement with a high content of aluminates can also be destroyed by the action of strong alkalis. In addition, it should be borne in mind that if cement concrete. is saturated with an alkali solution (caustic soda or potassium) and then dries, then under the influence of carbon dioxide, soda or potash are formed in the cement stone, which, crystallizing, expand in volume and destroy the cement stone.

Oil and petroleum products (kerosene, gasoline, fuel oil, petroleum oils) do not pose a danger to cement if they do not contain large amounts of naphthenic acids or sulfur compounds, however, light petroleum products quickly penetrate through ordinary concrete.

Aggressive action of mineralized waters

To protect against the aggressive action of mineralized waters (in particular sea water), high-density concretes are used; they are made using special types of cements in which free calcium hydroxide is not released or is released only in small quantities, and also contains less or no tricalcium aluminate.

These include aluminous cement, sulfate-resistant Portland cement, cement with active silica additives (the so-called pozzolanic Portland cement) and slag Portland cement. However, these cements cannot resist the action of free strong acids. To protect structures from the action of acids, it is necessary to use special acid-resistant materials: glass, ceramics, natural or fused stone, acid-resistant cement and concrete.

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Concrete corrosion

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

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

What leads to rusting of the reinforcement cage

There are several reasons for rust to appear on the metal inside the concrete mass. And these are not always external influences.

• Internal corrosion can be caused by the presence of a large number of aggressive components in the water used to mix the concrete mixture. 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 when used in any environment.
• The density of laying the concrete mixture is of no small importance. The fact is that the presence of a large number of pores, voids, cavities allows moisture and air to penetrate inside the product, to the reinforcement frame. 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 while the concrete gains strength to a given value.

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

• Study of the composition of 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 altered structure of concrete in a structure using a magnifying glass. This method allows you to identify many surface defects.
• Powerful microscopes help to detect the nature of the arrangement and connection of cement stone elements with aggregate grains. As well as the state of contact of concrete with reinforcement, dimensions and direction of propagation of cracks.

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

How to protect concrete from corrosion

Methods for protecting concrete and reinforced concrete structures from damage due to rust can be divided into the following options:

• Adjust the composition of the concrete mixture 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 binders with special properties. For example, belite cement, which reduces the formation of calcium hydroxide.
• Use products to protect reinforcement in concrete from corrosion during the formation of a steel frame.
• Treat the external surfaces of structures with hydraulic mixtures.
• Use measures to coat concrete with anti-corrosion agents that have the property of deep penetration into the body of the product.

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

• sulfate-yeast mash;
• organosilicon preparation;
• soaponaft.

This category can also include methods and means that protect the metal inside the mass of reinforced concrete products. Usually these are anti-corrosion drugs.

Secondary protection of concrete from corrosion is provided by external coating of concrete structures with paints, mastics, or impregnations with sealing properties.

A good result is achieved by a waterproofing adhesive coating. However, the best effect can be achieved by using primary and secondary protection together.

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.

Source: https://betonopedia.ru/beton/korroziya.html

Protection of concrete from corrosion

Many building materials, including concrete, are susceptible to corrosion. It represents the destruction of metals under the influence of physicochemical or chemical environmental factors. To prevent destruction in structures made of concrete and reinforced concrete, there are various protection methods. This can be surface coating using a special resistant material or a variety of varnishes and impregnations.

Definition of corrosion

Corrosion is the erosion of building materials under the influence of physical, chemical and biological factors upon contact with the environment. Concrete contains the least durable component - cement stone. It is from this part of the material that the corrosion process begins. Destruction occurs as a result of exposure to various types of water, namely:

• sewage;
• water in trenches or pipes;
• marine;
• river;
• ground.

The most dangerous groundwater for concrete is near industrial enterprises due to the presence of chemical emissions in them. Also, when exposed to concrete and reinforced concrete, wastewater causes significant harm to them. Concrete corrosion affects hydraulic structures and pollutes the air; however, such a concentration of gas in the environment does not harm human health, but contributes to the destruction of concrete structures.

The destruction of building materials is varied and destructive microorganisms can be found both in direct contact and inside the structures. Corrosion in concrete accelerates with high environmental humidity.

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Types and description

Sulfate corrosion.

There are types of concrete corrosion:

• Radiation, which depends on the dose of ionizing radiation and the amount of cement stone. As a result, the crystal lattice of minerals is distorted, the filler expands, which leads to microcracks, macrocracks in the material, and subsequently to complete destruction.
• Chemical, occurring as a result of precipitation and under the influence of carbon dioxide, which is part of the air. Thus, gas corrosion occurs in construction, which is especially relevant when there is a large amount of moisture.
• Biological. Corrosion associated with biological corrosion appears as a result of exposure to chemicals resulting from the operation of concrete structures.
• Physico-chemical corrosion occurs as a result of water freezing. In a liquid state, water enters the pores of the material, and as a result of sub-zero temperatures it freezes. The resulting ice expands and bursts apart buildings, resulting in cracks.

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Chemical corrosion

Formed by the interaction of concrete stone with environmental substances. Chemical corrosion processes fall into three categories:

• As a result of crystallization of materials, cracking occurs. Cracks are a consequence of expansion of the material volume due to low temperatures.
• Leaching by soft waters with the subsequent formation of a white coating.
• The cement bacillus, which is a consequence of moisture, destroys concrete structures. Cracks and cracks form on them.

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Biological destruction

Corrosion with the formation of large volumes of biological compounds in stone is the result of the influence of various substances penetrating into concrete. This contributes to the appearance of internal stress and cracks in the concrete structure. Biological corrosion is determined by the presence of bacteria, mosses, fungi or lichens on the cement stone.

Biological destruction develops due to direct contact of microorganisms with the material. As well as biological organisms that can harm the material from a distance. Biological corrosion develops in a technogenic environment with a high moisture content in the atmosphere.

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Radiation

Concrete corrosion can be radiation corrosion, which occurs as a result of radiation. It helps remove crystallized liquid from the concrete structure and thereby leads to a breakdown in the strength of the structure. Prolonged exposure to radiation leads to a liquid state of crystalline substances. Tension appears in the concrete solution, and cracks appear.

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Factors of influence

Concrete corrosion occurs under the influence of the following circumstances, which determine the rate of destruction of buildings and structures:

• the ability of the surface of the concrete solution to resist substances;
• material porosity;
• substances found in precipitation;
• capillarity.

a component of concrete is its porosity, which determines the number of pores and the presence of density in the structure of the material. The porosity of concrete determines the ability of the structure to absorb moisture when melting snow masses or other atmospheric precipitation .

A material with a significant number of pores is subject to a greater possibility of destruction as a result of physical and chemical corrosion.

Therefore, protecting concrete from corrosion should begin at the initial stage of construction of buildings and structures, because all types of concrete corrosion lead to the destruction of buildings.

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Anti-corrosion protection

Protection of concrete from corrosion.

The types of corrosion damage to concrete are different and varied. Many builders are interested in the issue of protecting concrete structures from the influence of negative external environmental factors.

The upper layers of concrete are often subject to destruction, then protection consists of using concrete with a small number of capillaries in its structure. Using a preparation against cracks at the initial stage of construction will help protect structures from leaching and washing out.

Protection against destruction in the form of rust is divided into:

• methods that change the composition of concrete, while making it more durable and resistant to negative environmental influences;
• activities related to covering the surface of the material with hydraulic preparations;
• combined measures that include coating concrete with an anti-corrosion agent with its further penetration deep into the material.

The use of belite cement in concrete will reduce the amount of calcium hydroxide released, which promotes the evaporation of liquid. Such a component will compact the material and thereby stop the penetration of liquid through the concrete solution.

Another type of destruction of a concrete structure from rust is sulfate corrosion of concrete. It appears as a result of the interaction of sulfates with stone in the cement of the solution. Destruction is observed in the form of distortion of the structure and expansion of structural elements.

The metal parts of the structure are covered with special protective materials.

Corrosion of concrete caused by exposure to water is prevented in different ways. A variety of additives and preparations are used at the initial stage of preparing concrete mortar: drainage or waterproofing.

Protection of concrete against corrosion is divided into: primary and secondary. Reinforced concrete structures are also susceptible to corrosion by rust. To save them, metal corrosion inhibitors are used at the time of preparing the concrete solution. Thus, a film is formed on the reinforced concrete components, which stops the contact of the metal with the concrete.

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Primary

This protection is due to the introduction of additional drugs into the concrete mixture during its preparation. This method will allow you to change the composition of the mixture and protect buildings and structures from destruction in the future.

A variety of stabilizing, waterproofing, plasticizing, biocidal and other preparations are used. When choosing auxiliary preparations for making a solution, they take into account the operating conditions of the concrete stone. For example, when making cement mortar in waters with a high sulfate content, the amount of lead is reduced.

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What is used?

Chemicals improve concrete mortar and its strength characteristics. They allow you to reduce aggressive substances in the pores, which slow down when moving. This means that corrosion of reinforcement in concrete is subject to less corrosion.

Using chemicals as additives in cement mortar increases the pore closeness. Thanks to this, high frost resistance of concrete and reinforced concrete is formed.

 Chemical additives are used: antifreeze, air-absorbing, sealing, retarding agents.

The use of additives in concrete mixtures that increase frost resistance.

Additives are used that can improve a couple of indicators at once or, conversely, improve one and reduce the other. To protect concrete structures from corrosion of its components by rust, the following additives are used:

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

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Secondary

Secondary protection against rust destruction of concrete structures and reinforced concrete buildings consists of a protective coating of the top layer of cement stone. The protection consists of paint coatings and sealing impregnation. It also includes keeping the concrete exposed to air for a certain time.

Conclusion

Corrosive effects are dangerous for concrete buildings and reinforced concrete structures. It is important to monitor buildings and in every possible way prevent the appearance of corrosive rust. Otherwise, the building, which took a lot of effort and money, may completely fall. There are many different additives on the building materials market that can save a building from destruction.

The main thing is to take measures both during work and at the time of preparing the solution, and to maintain the structures in the future, so that concrete corrosion does not destroy all the work.

Source: https://kladembeton.ru/poleznoe/korroziya-betona.html

Articles

" Back

As you know, concrete does not last forever and is susceptible to corrosion when exposed to the external natural environment. Corrosion processes occurring in concrete, as a rule, differ into three main types (groups).

Each of these groups, in turn, has its own key characteristics by which they are classified into species.
And of course, just like each type of destruction associated with corrosion of reinforced concrete structures, it also has its own specific means of restoration.

But still, let's look at everything in order. So
     

Three types of concrete corrosion

• 1 type of concrete corrosion is caused by leaching. This is when, under the influence of fresh water (soft water), the main components of cement (cement stone) dissolve and penetrate through the thickness of the concrete to the outside during the filtration process.

• Type 2 of concrete corrosion occurs due to the reaction of metabolic processes between the components contained in water and concrete, forming soluble components or products without astringent (fastening) properties, ultimately weakening the structure of the cement stone.

• The 3rd type of concrete corrosion occurs with the gradual accumulation and crystallization of salts in the capillaries, pores and cracks of the cement stone, which contribute to the occurrence of stress and internal destruction of reinforced concrete.

That is, based on this, we can classify and conclude the following:

Type 1 is leaching corrosion.

It consists of: the gradual dissolution and leaching of the components of the cement stone itself from the concrete product due to the filtration of soft (fresh) water through the very thickness of the concrete. In this case, the chemical balance between the liquid in the pores and the constituent components of the cement stone is disrupted.

This ultimately leads to a gradual weakening, affecting the mechanical strength and leading to the destruction of the concrete/reinforced concrete structure. A characteristic external sign of this type of corrosion is the appearance of a white coating on the walls of concrete structures, where water exits during filtration.

Type 2 is acid corrosion.

This corrosion is caused by the action of acids, salts and alkalis of an organic and inorganic nature, when easily soluble salts are formed in concrete. In this case, easily soluble salts are washed out of concrete, and the resulting residual products are present in the form of loose masses that do not have viscosity properties that affect strength.

This type of corrosion can completely destroy cement stone due to the dissolution and leaching of the formed chemical reaction products under the influence of acids.

Type 3 is salt corrosion.

The third type is caused by the destruction of concrete due to crystallization of salts and evaporation of mineralized water in the pores and capillaries of concrete. — This causes internal stresses (volume expansion in the pores of cement) and cracks in the concrete structure. This type of corrosion also differs in the specificity of the action of certain chemical groups: sulfate and magnesium, based on the content of chemical compounds in liquids of an aggressive environment in contact with the cement stone .

According to experts, under the influence of the sulfate group, the destruction of concrete occurs due to its shrinkage and expansion or swelling of aluminates (chemical elements) in the cement stone. In the second (magnesian) - the destruction of concrete occurs due to the formation and appearance of looseness and loss of binding properties in the cement stone , which can lead to persistent severe destruction of structures.

This is a general holistic picture of the causes of concrete destruction, with consideration of 3 main types of corrosion.

When we have clearly seen this “landscape” of destruction from the inside, what can we do to eliminate it?! There are a great many options to consider, but we only need EFFICIENCY and RELIABILITY!

Reliable solution for effective WHITEMIX

High-strength dry building mixtures VAYTMIX have proven excellent in restoring concrete structures damaged by corrosion and protecting concrete from corrosion. They offer several options for effectively solving the problems facing builders. Given the types of destruction considered, the WAYTMIX company is ready to provide repairmen with several types of mixtures to choose from to protect concrete from corrosion.

Both ready for this, and specially prepared for a specific task at hand and a specific type of destruction. At the same time, specialists: go to the site, conduct a destruction analysis, select the composition of the mixture for a given object, test it and provide all the documents - certificates, research and test reports.

Of the ready-made high-strength non-shrinking mixtures, the WHITEMIX company offers a line of effective solutions, where the WHITEMIX RT 40 brand stands out for these purposes. This is a thixotropic repair mixture of high-quality cement with a set of polymer additives, fiber and coarse aggregate (fraction up to 2.5 mm). It is used to eliminate concrete damage associated with corrosion and having a depth of 20 to 60 mm.

The hardened composition has good adhesion to old concrete up to 20 kg/cm2, no shrinkage, high frost resistance F300 and water resistance W18, crack resistance due to the presence of fiber (flexural strength up to 125 kg/cm2).

Repair using the mixture VAYTMIX RT40 of the reinforced concrete monolithic ceiling of the boiler room of JSC MZ "Arsenal", St. Petersburg, 2012.
The result of operation for 40 years, constant water leaks from a container standing on the ceiling	After renovation

You can find out more about this on the pages of the website, where all the brands of high-strength WHITEMIX mixtures we present are reviewed in detail.

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Types of concrete corrosion, ways to prevent its destruction

The service life of concrete structures is designed for a long period of time - from 60 to 100 years. But in practice, after 2-3 years, traces of corrosion and chipping may appear. Why this happens and what should be done to prevent concrete corrosion will be discussed in detail in this article.

Main types of corrosion processes

The class and grade of concrete depend on the percentage of cement in the composition. It is the quality of cement that determines such properties of the mixture as frost resistance and water resistance of concrete. But there is another important characteristic - the mobility of the mixture. To achieve the desired parameters of spread, rigidity and degree of compaction, plasticizers are added to the mixture. This avoids the formation of large pores and air pockets and protects the structure from corrosion in the future.

Under no circumstances should you replace special products with household chemicals. The ease of laying concrete can be ensured, but its strength and durability cannot be ensured.

With the help of additives, the appearance of large pores is eliminated, while concrete itself is a porous material. This is due to the fact that the mixture uses water, which evaporates when dried. The resulting pores become a loophole for destructive effects.

Corrosion is divided into four types:

• physico-chemical;
• biological;
• chemical;
• radiation.

Destruction of concrete from radiation is the rarest occurrence, despite the fact that crushed granite stone used in some mixtures has its own radiation background. But it is so insignificant that it cannot significantly affect the strength of the structure.

Corrosion from radiation occurs as follows:

• long-term exposure to radiation changes the crystalline state to an amorphous one;
• the structure of the material is disrupted and strength decreases;
• Internal stress increases and cracks appear in the concrete.

Physico-chemical factors

The more freezing and thawing cycles that occur, the more moisture penetrates into the pores. At low temperatures, water turns into ice crystals, which expand and gradually destroy the structure. As a result, the concrete cracks and crumbles.

Biological reasons

Violation of operating conditions can cause biological corrosion of concrete. With constant dampness, microorganisms develop on the surface of structures, the waste products of which have a destructive effect on the structure of concrete.

Chemical exposure

Atmospheric precipitation combined with carbon dioxide can have different effects on concrete structures depending on what remains on the surface as a result: chlorides, carbonates, sulfates or nitrogen oxide. Three types of corrosion processes can occur in this way:

1. Leaching with low-hardness waters results in the leaching of components soluble in an alkaline medium. Signs of the process are white deposits or streaks. Sometimes such a chemical reaction only increases the resistance of concrete to external influences due to the formation of a colloidal layer.
2. Crystallization due to the formation of poorly soluble compounds. Upon contact with sulfates, such compounds crystallize and expand the concrete.
3. Cracking due to moisture in the atmosphere occurs due to the formation of loose, poorly soluble substances, which over time penetrate from the surface into the structure. Exchange reactions increase the corrosion of concrete.

All protective measures must be carried out in combination:

• correct determination of the design grade of concrete;
• purchasing from companies that adhere to production technology;
• competent installation and control of strength gain until 70% of the design value is achieved;
• preventing rapid drying and exposure to direct sunlight during this period;
• use of techniques for waterproofing the surface of structures.

Constant dampness should be avoided in cases where bridge concrete was not used for the construction of structures. If necessary, treat with antiseptic impregnations or dry mixtures.

Ironing of surfaces

To increase strength and resistance to moisture and chemicals, concrete is often reinforced.

This method is used at the stage of formal hardening of the mixture, when mixtures with sodium aluminate, liquid glass, corundum, granite or quartz fillers are rubbed into the surface.

Polymer reinforcing additives improve adhesion and enhance the ironing effect. The disadvantage of this method is that it is done manually and is quite labor-intensive, so it is suitable for use on small objects.

Waterproofing compounds and materials

This type of corrosion protection includes a whole list of techniques:

• injection;
• penetrating;
• dividing

The injection method is innovative, quite expensive and requires special equipment, with the help of which a gel-like substance is introduced into the structure. A dense, waterproof membrane is formed that is highly effective at preventing the penetration of liquids.

The penetrating method , on the contrary, is easy to use, and special equipment will require a spray gun to optimize the process of applying waterproofing. This method can be used on wet surfaces, since water acts as a catalyst.

A new portion of moisture triggers the chemical process of crystallization, which only improves the strength characteristics of concrete.

An additional advantage worth noting is the vapor permeability of the crystalline layer formed after applying waterproofing compounds, which eliminates the greenhouse effect.

And the last method involves creating a separating layer between the concrete surface and finishing materials. The planes of the structures are coated with polymer, bitumen-latex and polyacrylic compounds. This guarantees an increased level of moisture insulation, fire safety and frost resistance. The advantages include the low cost of the method, and the disadvantages include the impossibility of use if the project does not provide for decorative finishing.

With proper design, construction and operation of concrete structures, their durability exceeds the service life of buildings made of any other materials. If there are any doubts that you will be able to complete all stages of construction correctly on your own, then you should definitely turn to professionals.

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