KR20220165450A - Repair technology of cathodic polarization for rebar and porous water proof for outworn reinforced concrete - Google Patents

Abstract

The present invention relates to a repair technology on a damaged concrete unit due to aging and deterioration of a ferroconcrete structure. The conventional domestic repair technologies (patented technologies, new technologies, etc.), as in the figure, in general, when ferroconcrete structures are damaged to have a reduced strength, uses the methods to treat for preventing corrosion by resin-based paint for rebars as in the figure, to fill the damaged concrete parts with high-strength, high-alkaline repair mortar, and to perform the waterproofing treatment on the surface with a non-ventilation waterproofing material. Here, if a potential reverse phenomenon (a phenomenon where the relative positive pole and negative pole are reversed) occurs in rebars penetrating the repaired parts and the non-repaired parts, an even bigger concrete damage will occur by the corrosion of the positive pole reaction battery in the rebars of the non-repair parts, thereby reducing the repair cycle. The present technology is a new technology which is able to suppress the potential reverse phenomenon of rebars, which the conventional repair technologies all have in common, by applying an inorganic paint with the negative polarization function, and to simultaneously reduce the positive pole reaction battery corrosion in the rebars by applying a ventilation waterproofing agent.

Description

Repair technology of cathodic polarization for rebar and porous water proof for outworn reinforced concrete}

The present invention is a repair technology by applying a paint having an electrochemical negative polarization function to the reinforcing bars of an old and deteriorated reinforced concrete structure and applying a breathable waterproofing agent to the surface of the repairing part. It is a technology that improves safety and economy by improving the maintenance cycle by suppressing

The phenomenon of early concrete damage and shortened repair cycle in existing reinforced concrete structures in Korea has various technical and policy backgrounds, and these backgrounds are the background of the development of this technology.

Existing domestic reinforced concrete repair technologies (patents, new technologies, various guidelines, etc.) generally cause corrosion problems in reinforcing bars due to concrete deterioration as shown in Figure 1. After expanding and arranging the parts, surface treatment for the exposed reinforcing bars, apply a bipolarizing resin-based paint (e.g., epoxy, urethane, fluororesin, etc.), and fill the damaged concrete with high-strength, high-alkaline repair mortar, As shown in Fig. 8(F), it is common to treat surface waterproofing with non-permeable waterproofing materials, and some of them have been recognized as new technologies by adjusting the strength and pH of the repair mortar. At this time, as shown in Fig. 9, if a potential reversal (relative negative/positive change phenomenon) occurs in the reinforcing bar penetrating between the repaired part and the non-repaired part, before the early repair by anodic reaction battery corrosion in the non-repaired reinforcing part Larger-scale concrete damage problems may occur.

This phenomenon is the result of the policy background. With about a century of history in the United States, Japan, and the United Kingdom, which have similar corrosive environments to Korea, we have developed method engineering to study metal corrosion problems electrochemically, and at the same time, a policy to train and utilize various professional technicians for corrosion protection. (Example: 10 types in the US, 4 types in Japan), but in Korea, the phenomenon that inevitably occurs by excluding method-related policies can be called the policy background.

The following are basic data related to corrosion of steel bars in reinforced concrete, which are common sense and utilized in advanced countries with anticorrosive technology policies.

1) Deterioration and impact of concrete

Types of deterioration that decrease the quality of concrete include neutralization, freeze-thaw action, chloride action, and ettringite of sulfate. When concrete is deteriorated by these causes, it affects the strength of concrete itself. At the same time, it has a direct or indirect effect on the corrosion of internal reinforcing bars. When the reinforcing bars in a reinforced concrete structure are corroded, the volume expands about 3 to 5 times, so the concrete in contact with it is damaged, resulting in a shortened safety life.

Therefore, it is necessary to find out the factors that deteriorate concrete and remove them technically.

(1) Neutralization

Concrete is a high-strength construction material made by mixing sand, water, and gravel with ceramic cement. When cement undergoes hydration with water, about 30% of Ca(OH) ₂ , a highly alkaline component, is produced, so sound concrete has a high alkalinity (PH≒12~13).

Therefore, it has the function of passivating and protecting the internal reinforcing bars. However, expansion by heat of hydration (about 60~70℃) generated when concrete reacts with water and contraction reaction when cooled cause microscopic cracks to occur, and concrete is formed by capillary tubes formed by evaporation of water for pouring during drying. As the water touches the surface, moisture penetrates into the inside as shown in Figure 1.(B), and at this time, carbon dioxide (CO ₂ ) in the atmosphere is also introduced at the same time, resulting in a reaction as shown in Equation (3), resulting in strong alkali of concrete. The factor Ca(OH) ₂ is neutralized with neutral CaCO ₃ and the pH drops below 10.

Currently, the criterion for neutralization of concrete is pH 10.

The following is the hydration reaction of concrete.

In other words, when Ca(OH) ₂ , an alkali component generated in the hydration equations (1) and (2) of concrete, is changed to neutral CaCO ₃ by moisture and carbon dioxide gas penetrating from the concrete surface, the pH of concrete changes from 12.5 to 10 At this point, the concrete is evaluated as neutralized.

When the neutralization of concrete proceeds to the reinforcing bars as shown in the figure, the potential of the reinforcing bars becomes negatively polarized to the corrosion potential as shown in the figure, forming a corrosion cell with the surrounding reinforcing bars, and the corrosion rate increases due to anode reaction battery corrosion, which damages the concrete. do. (When reinforcing bars corrode, the volume expands about 3 to 5 times)

Figure.2 shows the potential relationship of rebar according to pH change, and Table.2 shows the experimental value of the corrosion tendency of steel according to pH change.

The following is the empirical formula and neutralization rate presented in relation to the neutralization rate of concrete.

here

W = water-cement ratio

X = Depth of Neutralization

R = neutralization rate

(2) freeze-thaw action

When freezing and melting of moisture are repeated on the concrete surface subjected to rapid temperature changes, cracks propagate on the surface and the concrete deteriorates. This surface damage proceeds in the following order.

In order to suppress this freeze-thaw action, an air entraining agent (AE agent) is applied. Fig. 3 shows the experimental values for the air entraining agent.

3) Chloride action

Early (before the 1990s), calcium chloride was added around 1 to 2% of the amount of cement worldwide for the purpose of promoting hardening and preventing freezing of concrete during concrete placement.

However, since it was discovered that calcium chloride added to concrete has a bad effect on corrosion of internal reinforcing bars, the application of calcium chloride has been banned worldwide. Figure.4 is the experimental data showing the change trend of the surface potential of the rebar according to the amount of salt.

As shown in Figure.4, when the chloride content in concrete is 0.04 to 0.09%, the concrete protects the reinforcing bar by positively polarizing it over time, but at 0.16% or more, the negative polarization increases over time, which tends to promote corrosion of the reinforcing bar. It can be seen that there is

This shows that the negative polarization tendency of the reinforcing bar increases as the chloride content increases.

(4) Ettringite sulfate (Ettringite)

There are many cases in which reinforced concrete structures are greatly damaged by soil or seawater containing sulfate. This is because sulfate reacts with calcium hydroxide (Ca(OH) ₂ ), an alkali component in concrete, to make gypsum (CaSO ₄ ), which in turn reacts with calcium aluminate to form ethylene oxide (3CaO-A1 ₂ O ₃ 3CaSO) with a large volume. ₄ 31H ₂ O).

Table 4 compares the effects of various sulfate-containing soils and solutions on concrete.

Meanwhile, magnesium salts and ammonium salts in concrete may also react with calcium hydroxide to form ethringite as follows.

Mg(OH) ₂ produced here is precipitated as a solid with low solubility, and NH ₂ escapes as a gas. Therefore, it results in reducing the amount of Ca(OH) ₂ in concrete. And the gypsum (CaSO ₄ ) produced at this time produces ettringite through the following reaction.

In order to reduce the impact of sulfate, sulfate-resistant cement with a lowered content of 3CaO Al ₂ O ₃ is prescribed and used in an environment where sulfate is over 1,500 ppm, and research is being conducted to apply admixtures such as blast furnace slag or phosran. have been studied in depth

However, since seawater contains about 2,500 ppm of sulfate, 5 types of cement with maximum reduction of 3CaO·Al ₂ O ₃ were used for reinforced concrete structures (especially nuclear power plants) in salt-damaged areas from early on.

However, since the fact that about 17,000ppm of chloride contained in seawater has a greater effect _on reinforcing steel corrosion when 3CaO·Al2O3 is reduced, the use of class ₅ cement has been banned in marine reinforced concrete structures.

In Korea, it is reported that there is a performance of importing and applying class 5 cement in the construction of a nuclear power plant, and some application in the early stage of the construction of a new airport.

Recently, a method of applying mixed cement with blast furnace slag or phosran is being studied.

2) Corrosion and Method Theory of Rebar

(1) Corrosion theory of steel

Steel is produced by reducing iron oxide (Rust), which exists in nature, by heating it. Therefore, steel is characterized by being oxidized when it is in contact with water and oxygen in the air and returning to its original form, that is, iron oxide (Fe ₂ O ₃ : rust). When moisture and oxygen come into contact with the steel surface, the oxidation reaction proceeds as follows.

· Anode reaction

Oxidation reaction of metal (ionization reaction)

· Cathodic reaction

Reduction reaction of environmental components (electron consumption reaction)

Battery reaction between negative and positive electrodes

In case of lack of oxygen, Fe ₃ O ₄ nH ₂ O

2) Pourbaix diagram

M. Pourbaix early showed the corrosion characteristics of steel as a picture by combining the thermodynamic formula and experimental values. In other words, as shown in Figure.5, the Y-axis represents the corrosion potential of metal, and the X-axis represents the pH of the environmental component. Figure.5 is the corrosion degree of steel. (Every metal has its own corrosion rate.)

*Pourbaix diagram is also expressed as potential-pH of OO metal, corrosion degree of OO metal, etc.

In Fig. 5 the following steel corrosion properties can be read.

· Steel corrodes in neutral aqueous solutions. (Corrosion potential: -0.65 Volt)

· If the potential of the steel is raised (① in Fig. 5), the surface of the steel is passivated.

· When the potential of the steel is lowered (② in Figure 5), the surface of the steel is stabilized.

· When steel is exposed to high alkalinity (Fig. 5 ③), the surface of the steel becomes passivated.

Here, ① in Figure 5 is an anode method (Anodic protection). ② is called cathodic protection, and ③ is called alkalinity protection.

(3) Lecture method theory

The method theory of steel is explained based on the corrosion theory.

Table 5 shows the basic method theory derived from equations (9), (10), (11) and Figure.5 Pourbaix diagram.

① Blocking the contact of moisture on the surface of the steel, which serves as a circuit of the corrosion battery, suppressing the battery reaction of metal (see Equation (9))

② In conditions where water is in contact (e.g. boiler, water tank, piping), dissolved oxygen in the water is removed to suppress the reduction reaction (see equation (10))

③ A method of passivating the surface by anodic polarization of the potential of the metal (Figure 5 (1))

④ Stabilization method by cathodic polarization of metal potential (Figure 5 (2))

⑤ How to passivate the metal surface by alkalizing environmental components (Figure 5 (3))

Table 5 is a comparison between lecture method theories.

3) Method technology to block moisture contact on the surface of rebar

(1) Resin painting

Insulating resin is applied to reinforcing bars to prevent contact with moisture and prevent corrosion. Rebar painting uses a dedicated painting machine. When reinforcing bars are inserted into the painting machine

In the process, an insulating epoxy coating film is formed on the outside.

It was developed in the United States in the 1960s and was intensively applied in the construction of marine bridges. After about 10 years of application, the rate of cracking in concrete was higher than that of general reinforcing bars, so the American Concrete Institute analyzed the cause. As a result of the study, it was confirmed that the damage to the film is a crack caused by battery corrosion, as a small anode-to-cathode corrosion battery is formed in which the damaged film (cutting surface, splitting of the coating during bending) that occurs during cutting and bending in the process of reinforcing is relatively anode. At the same time, a rule was added to prohibit the use of epoxy-painted reinforcing bars in bridge construction in the concrete specification. In Korea, some cases of use in the piers of Seohae Bridge, Yeongjong Bridge, and Gwangan Bridge have been reported.

(2) Zinc plating

When general rebar is immersed in a hot-dip zinc bath after going through pickling and water washing, the surface is galvanized. Zinc-dipped rebar has better adhesion to concrete than resin-coated reinforcing bars (adhesion to resin-coated reinforcing bars is about 80% of that of general reinforcing bars), and above all, the damage to the coating that occurs during the reinforcement process acts as a relative cathode. However, since the reinforcement is protected by the cathodic protection effect of the sacrificial anode, it has been evaluated as an ideal reinforcement method and has recently been widely applied to offshore reinforced concrete structures. In Korea, no case has been reported so far, but it is recommended to use it in highly corrosive areas including salt-damaged areas in the future. Galvanized rebars can be applied according to the work standards for general rebars.

(3) Surface waterproofing

Among the reinforcement method technologies for reinforced concrete structures, the surface waterproofing technology is evaluated as the most economical technology. Therefore, surface waterproofing technology has been developed and applied over a long history. Among them, the organic resin waterproof coating method has been widely applied worldwide, but recently, inorganic waterproof paints that have improved the environmental problems and adhesiveness problems of organic resin paints have been developed and are expanding the scope of application.

In addition, among the recently developed advanced inorganic waterproof paints, technologies with higher insulation functions are continuously developed and applied. In addition, among concrete surface waterproof technologies, waterproof sheets, linings, and waterproof mortar technologies with improved seawater resistance, chemical resistance, and impact resistance have been developed and used for special purposes.

(4) sphere waterproofing

Spherical waterproofing is a technology that prevents moisture from penetrating into the concrete by inserting a crack-resistant admixture during concrete pouring to suppress internal cracks caused by the heat of hydration generated during concrete curing. Concrete waterproofing materials are generally produced in liquid form, but in Korea, there is a case in which powder-type concrete waterproofing materials have been recognized as a new technology. It is a reinforcement technology that is widely applied to offshore structures with strong corrosiveness, water tanks that are always in contact with water, and sewage treatment plants.

4) Passivate the surface with bipolar polarization

As shown in Figure.5 and Table.5, if the surface potential of the reinforcing steel is positively polarized to a certain extent or more, the progress of corrosion can be effectively inhibited by passivation. In reinforced concrete structures, nitrite-based corrosion inhibitors with anodic polarization are mainly used. Application is mainly used for reinforced concrete structures (port facilities, bridges) in salt-damaged areas, and when applied to riverbed bridges, water purification plants, and sewage treatment plants in inland areas, it can economically improve the corrosion problem of reinforcing bars.

5) Stabilize the surface with cathodic polarization

Corrosion of rebar can be effectively prevented by the cathodic protection method, which suppresses corrosion by supplying electrons to negatively polarize the metal surface.

Figure.6 is a schematic diagram of the electric protection method applied to reinforced concrete. In actual application, the external power cathodic protection technology is mainly applied, and in this case, it is common to use -100mV (-0.1Volt) negative polarization as the standard.

In other words, AC power is converted into DC power through a rectifier, and then the negative electrode (-) is connected to the reinforcing bar, and the positive electrode (+) is connected to the insoluble anode installed on the surface (mostly titanium is used a lot). By supplying electrons to negatively polarize the potential to about -100mV (-0.1Volt), corrosion of rebar can be effectively prevented.

This technology is an oxidation reaction in which electrons are lost when moisture comes into contact with the steel surface, and the steel is separated into ions.

That is, Fe->Fe ^{2 +} +2e ^- (see Formula 9)

When electrons are supplied to the steel to negatively polarize the potential, the oxidation reaction of the steel does not occur and is stabilized. This cathodic protection technology for reinforcing bars is mainly applied to dock facilities and bridges in salt-damaged areas.

6) Passivation by alkalinization

Since concrete shows a high alkalinity of about 12 to 13 in pH due to the influence of Ca(OH) ₂ and Mg(OH) ₂ among the components, the internal reinforcing bars are passivated and protected.

Therefore, the following fragmentary theories have been proposed in relation to corrosion of internal reinforcing bars in reinforced concrete structures.

Even if sea sand is used as an aggregate, the reinforcing bars will not corrode if moisture does not come into contact with them.

Even if sea sand is used as an aggregate, the reinforcement will not corrode if the concrete is dry.

Since concrete is strongly alkaline, rebars do not corrode even when sea sand is used as an aggregate.

etc.

However, in relation to the corrosion problem of reinforcing bars in reinforced concrete structures, the corrosion characteristics of reinforcing bars should not be determined only by the strong alkalinity of concrete.

In other words, it is because the various causes of concrete deterioration listed above can also act as variables in the corrosion characteristics of reinforcing bars. Therefore, when discussing the theory of passivation of rebar by alkalization of concrete, the following points should also be supplemented.

Measures against factors that promote neutralization of concrete

Example: surface waterproofing, concrete waterproofing

Measures to restore neutralization for concrete structures that have undergone neutralization

Example: Alkali injection technology at the surface

As for the above neutralization restoration technology of reinforced concrete structures, manufacturers specializing in corrosion inhibitors are developing and providing various technologies.

7) Non-destructive corrosion diagnosis method of rebar

As a non-destructive corrosion diagnosis method for internal reinforcing bars in existing reinforced concrete structures, a method based on electric potential measurement and a method for determining corrosion resistance of reinforcing bars by measuring neutralization of concrete have been put into practical use.

(1) Potential measurement method

As the most widely used diagnosis method in the diagnosis of corrosion of rebar, the measurement and evaluation methods are shown in Figure.7 and Table.6.

In Figure.7, when a wire is connected between the negative electrode (-) of the high-resistance potentiometer and the reinforcing bar, and a sponge impregnated with water is inserted into the reference electrode connected to the positive electrode (+), and in contact with the concrete surface, as shown in Table.6. The potential of the same internal rebar can be read. The potential measured in this way can be data to evaluate the corrosive tendency of the reinforcing bar, but it is irrelevant to the evaluation of the amount of corrosion.

(2) Neutralization measurement method

As shown in Fig. 7, since neutralization of concrete in reinforced concrete structures is a direct cause of corrosion of reinforcing bars, the method of measuring neutralization of concrete is closely related to corrosion evaluation of reinforcing bars.

(The original neutralization standard is pH7, but the neutralization standard of concrete is pH10. When water and air penetrate into the concrete from the surface and change into Ca(OH), which is an alkaline component, and reacts with neutral CaCO, the concrete becomes pH<10 or less. Neutralization may occur.)

When the potential of the internal reinforcing bars is negatively polarized due to the change in the pH of the concrete, the corrosion rate increases significantly as shown in Table 6. Therefore, in the non-destructive corrosion diagnosis of rebar, the neutralization diagnosis of concrete can be said to be an indirect reinforcement corrosion diagnosis method. In the measurement of neutralization of concrete, it is common to use 1% alcohol solution of phenolphthalene as a reagent. That is, the neutralization depth is measured by color change by painting the reagent on a cylindrical core sampled from the concrete surface in the depth direction. The part that turns red when the reagent is painted is evaluated as sound concrete that has not been neutralized, and the part without color change is evaluated as neutralized with a pH of 10 or less.

8) Reinforced concrete damage and advanced repair technical data

(1) General reinforced concrete structures

If a general reinforced concrete structure is partially corroded due to deterioration of concrete as shown in Figure 1 and the concrete is damaged, repair it with the procedure shown in Figure 8.

(A): Healthy condition (concrete pH ≒ 12.5)

(B): Concrete neutralization progresses with moisture and CO ₂ intrusion at the surface (pH < 10)

(C): Concrete damage due to corrosion of reinforcing bars (expansion by 3 to 5 times the volume)

(D): before maintenance

(E): Clean up the damage

(F): repair damage

The above repair method for damaged reinforced concrete is a generalized repair technology that has been implemented for a long time. Recently, the repair technology that mixes a corrosion inhibitor with a positive polarization function in repair mortar has been recognized as a new technology and is expanding its application. .

However, the water tank repaired by applying the new technology is damaged in a short period of time due to electrical corrosion of the reinforcing bars near the repair part in a short period of time, resulting in a shortened repair cycle compared to the existing repair technology. A meeting is on the rise.

Figure 9 shows the potential relationship of reinforcing bars according to parts in the reinforcing part penetrating the repair part when the high-alkaline repair mortar that bipolarizes the potential of the reinforcing bar with high insulating resin coating and enhances the bipolarization function for the reinforcing bar in the damaged area. Same as

In addition, the data shown in Fig. 10 are used in the analysis of the potential change trend of the rebar according to the pH.

In Fig.9 and Fig.10 we can read:

As shown in (D) of Fig.8, the potential E① of the damaged part of the concrete is relatively lower than the potential of the reinforcing bar E② and E③ of the undamaged part, causing anode reaction battery corrosion of the corrosion battery.

That is, E①<E②<E③

And, as shown in (E) of Figure.8, if you clean up around the damaged part,

The relation E①=E②<E③ is established.

However, as shown in Figure 8 (F), when highly insulating anticorrosive coating is applied to the reinforcing bars and mortar with high alkali passivation function is filled, the potential of E① and E② is bipolarized by about 0.4 to 0.5 volts, and the potential around the repair part Due to the reversal phenomenon, anodic reaction battery corrosion may occur in the reinforcing bar ③ around the adjoining part.

Undesirable phenomena such as the above should be improved as follows.

first; In the reinforcement method of the damaged part, the anticorrosive coating of the anodic polarization function is applied as the anticorrosive material of the cathodic polarization function.

second; The repair mortar lowers the bipolarization function of the reinforcing bar and applies a mortar with a function similar to that of the existing concrete.

third; Surface waterproofing is carried out widely to prevent the formation of corrosion batteries between reinforcing bars.

KR.10-1708879(2017.02.15.)

(1) Explanation of causes and solutions of domestic corrosion problems Volume 2 P.76~P.99 (2015, Korea Corrosion Prevention Technology Association) (2) Method Technology Handbook Volume 3 P.1~P.83 (1998, Ministry of Construction and Transportation)

In the present invention, existing reinforced concrete structure repair technologies (patents, new technologies, maintenance guidelines, etc.) are treated with a resin-based paint (epoxy, urethane, fluororesin, etc.) with an anodic polarization function for the damaged reinforcing bars. , As shown in Figure 8(F), after filling with bipolar repair mortar, non-permeable waterproofing agent is applied, and the potential reversal phenomenon in which the potential of the damaged reinforcing bar becomes a relative cathode compared to the non-damaged reinforcing bar (relative negative in the reinforcing bar penetrating the damaged area) ·Anode change phenomenon) occurs, and concrete can be damaged on a larger scale than before repair by anodic reaction battery corrosion in non-repaired reinforcing bars.

In the damaged part of the reinforced concrete structure, the potential reversal phenomenon between the non-repaired reinforcing bars due to the excessive positive polarization of the reinforcing bars is suppressed by applying a negative polarizing paint, and the battery corrosion is suppressed by removing moisture by applying a breathable waterproofing agent.

Instead of applying resin-based paint with positive polarization function, which is applied for the purpose of preventing damage to reinforcing bars in existing technologies, it is treated with inorganic paint with negative polarization function (inorganic paint with combination of alloy zinc anode powder and inorganic binder). By applying a breathable waterproofing agent (a breathable surface waterproofing agent of a combination of electrolytic ionized water and a lithium-based surface waterproofing agent) instead of the non-permeable waterproofing agent of It suppresses battery corrosion with a porous water proof that releases moisture.

In the repair of old and deteriorated reinforced concrete structures, for cracks or deteriorated concrete damages, as in conventional repair techniques, for rusty reinforcing bars exposed after physical surface treatment (high pressure water spray, treatment of damaged areas with tools, etc.), tools Or, after surface treatment with a wire brush, etc., followed by anticorrosive coating with resin-based paint (e.g., epoxy, urethane, etc.), and then filling with high-alkaline repair mortar, the surface is polarized due to the formation of a negative film on the reinforcing bar in the repair part. Potential is improved. Therefore, a potential difference occurs between the reinforcing bars in the non-maintenance part due to potential reversal, and anode reaction battery corrosion occurs due to the potential difference in the reinforcing bars in the non-maintenance part, and concrete is damaged.

Therefore, in the reinforcing bar method, if the anticorrosion treatment is performed with a negative polarization paint (eg, zinc rich inorganic paint) instead of applying a positive polarization resin-based paint, the potential difference between the repair part and the non-repair part is minimized and the potential reversal phenomenon is suppressed. can do.

In addition, when an air permeable waterproofing agent with an inflow or discharge function of an electrolyte (eg water, etc.), which has an absolute effect on corrosion, is applied, the corrosion of the reinforcing bar can be effectively blocked and the strength of the concrete can be restored.

(1) Extend the safety life by improving the repair function of reinforced concrete structures, and improve technological competitiveness by promoting technology.

(2) Raise society's lack of awareness of corrosion to the level of advanced countries with anticorrosive technology policy and improve corrosion loss

(3) Economic development through export commercialization of technology

(4) Improvement of technical skills in the construction industry

It is possible to improve the corrosion problem of reinforcing bars in the repair part by applying anticorrosive coating with resin-based paint and high alkalinity repair mortar. However, excessive anodic polarization of the reinforcing bars also forms a potential difference between the non-maintenance reinforcing bars, and when a potential reversal phenomenon occurs, anodic reaction battery corrosion occurs in the non-maintenance reinforcing bars, reducing the repair efficiency. When applying negative polarization paint to the damaged reinforcing bar, it can improve the corrosion problem of the anodic reaction battery in the non-repair part due to potential reversal, and apply a breathable waterproofing material that blocks the inflow of electrolyte (e.g. water, etc.) and discharges the inherent electrolyte. , it is possible to obtain the effect of blocking corrosion in the reinforcing bar, so that the maintenance cycle can be extended.

1. Development of inorganic paint with negative polarization function when painting on rebar

- Zinc (purity: around 99.8) is alloyed with aluminum (purity: 99.9% or more) with a weight ratio of 3 to 5% to produce an alloy zinc anode with a material potential of -1,000 mw/sec or less and powder it (nano-sized particles)

- Manufacture of inorganic paint with negative polarization function, including silicate-based inorganic binder and alloy zinc anode powder.

2. Production of ion reduced water using magnesium electrode (pH≒10, ORP≒-20mv)

Claims (2)

Physical surface treatment of deteriorated concrete in an aged, deteriorated reinforced concrete structure;
Oxide removal and surface treatment steps for exposed rusty rebar
and reinforcing steel negative polarization protection step by applying inorganic paint containing alloy zinc anode powder with sacrificial anode function to the surface-treated reinforcing bar, and filling the damaged concrete part with high-alkaline repair mortar, and applying electrolytic ionized water and lithium-based inorganic binder to the upper surface. Technology to form a breathable waterproof film containing The concrete repair method of claim 1, wherein a negative polarity zinc rich paint is applied to rusted reinforcing bars in an old and deteriorated reinforced concrete structure, a highly alkaline repair mortar is filled, and an air permeable waterproofing agent is applied to the upper surface.