KR20230097742A - Electrochemical Deposition device with Zinc Paints as Anode Electrode And Re-passivation of corroded rebar in Concrete Structure - Google Patents

Abstract

The present invention relates to an electrochemical electrodeposition device using a galvanized film as an oxidizing electrode and a method for repairing concrete micro-cracks and inhibiting corrosion of reinforcing bars using the same, and more particularly, to an electrochemical electrodeposition device using an inexpensive galvanized film as an oxidizing electrode. An electrochemical electrodeposition device that uses a galvanized film as an oxidizing electrode that can repair micro-cracks in concrete while securing economic feasibility by preventing corrosion of reinforcing bars and a method for repairing micro-cracks in concrete and inhibiting corrosion of reinforcing bars using the same It is about.
A preferred embodiment of an electrochemical electrodeposition device using the zinc coating film of the present invention as an oxidation electrode includes: a water tank of a certain size; an electrolyte filled in the water tank; an oxide electrode formed of a galvanized film at the lower outlet of the water tank; It is composed of a absorbent cotton configured to cover the anode; so that the reinforcing bar corroded in the concrete by the rectifier becomes a cathode (-) and the anode is used as an anode (+) to apply current at a constant current density to generate electricity to undergo chemical electrodeposition.

Description

Electrochemical deposition device with Zinc Paints as Anode Electrode And Re-passivation of corroded rebar in Concrete Structure}

The present invention relates to an electrochemical electrodeposition device using a galvanized film as an oxidizing electrode and a method for repairing concrete micro-cracks and inhibiting corrosion of reinforcing bars using the same, and more particularly, to an electrochemical electrodeposition device using an inexpensive galvanized film as an oxidizing electrode. An electrochemical electrodeposition device that uses a galvanized film as an oxidizing electrode that can repair micro-cracks in concrete while securing economic feasibility by preventing corrosion of reinforcing bars and a method for repairing micro-cracks in concrete and inhibiting corrosion of reinforcing bars using the same It is about.

Deterioration of reinforced concrete structures proceeds through a process such as incubation period -> vibration period -> accelerator -> deterioration period, and when reaching the accelerator and deterioration period, very large maintenance/management costs are required to maintain durability. Hundreds of μm cracks generated in the propulsion phase rapidly degrade the performance of the structure and render it unusable through the accelerator and deterioration phase. When such micro-cracks occur, the diffusion rate of dissolved oxygen rapidly increases, accelerating the corrosion rate of the reinforcing bars. In general, when several cm cracks (gaps) occur in reinforced concrete structures, there are various repair and reinforcement methods such as epoxy injection. However, it is true that there is no way to repair or reinforce when cracks of tens to hundreds of μm occur. These micro-cracks gradually grow, and when faced with an accelerator and a deterioration period, they grow into cracks of several cm, resulting in a rapid increase in maintenance costs.

An insoluble anode such as Ti (titanium), Pt (platinum), or Ir (iridium) is used as the anode (oxidation electrode) used for electroplating, electromethod (cathode method), etc. using conventional electrochemical methods. This is to prevent consumption by using precious metals since current flows out from the anode when electroplating or electrocorrosion is performed. Due to this, constant current density is always possible. However, precious metals are very expensive, and there is a problem in that the cost increases when they have a large area.

As a background technology of the present invention, there is Patent Registration No. 1081991 "Artificial Crack Healing Method of Concrete Cracks Using Electrochemical Electrodeposition Technique" (Patent Document 1). In the background art, 'injecting an electrolyte into the cracked part of the concrete structure; arranging an anode to electrically contact the electrolyte solution; applying a current so that the anode and the cathode are energized using an electrically conductive member installed inside the concrete structure as a cathode; and performing the electrochemical reaction by an applied current to precipitate an electrodeposited material in the crack portion; Including, but the electrolyte solution is MgCl2 of molarity 0.1 ~ 0.5 mol / ℓ, and the current density of the current is 0.01 ~ 0.03 A / m2 Artificial crack healing method of concrete cracks using electrochemical electrodeposition technique, characterized in that suggests

However, the background art has a problem in that it is composed of an electrochemical cell structure that is impossible to use in the field.

Patent registration No. 1081991 "Artificial crack healing method for concrete cracks using electrochemical electrodeposition technique"

The present invention is to solve the above problems, and economically and effectively increases the life time of the structure by using a galvanized film as an oxidation electrode for filling micro-cracks irregularly scattered in a concrete structure and suppressing corrosion of reinforcing bars due to this. The purpose of the present invention is to provide an electrochemical electrodeposition device and a method for repairing concrete microcracks and suppressing corrosion of reinforcing bars using the same.

The present invention and a tank of a certain size; an electrolyte filled in the water tank; an oxide electrode formed of a galvanized film at the lower outlet of the water tank; It is made up of a absorbent cotton configured to cover the anode; so that the reinforcing bar corroded in the concrete by the rectifier becomes a cathode (-) and the anode is used as an anode (+) to apply current at a constant current density to generate electricity It is intended to provide an electrochemical electrodeposition device using a galvanized film as an oxidation electrode, characterized in that it allows chemical electrodeposition.

In addition, it is intended to provide an electrochemical electrodeposition device using a galvanized film as an oxidation electrode, characterized in that the electrolyte is saturated MgCl ₂ or ZnCl ₂ .

In addition, of saturated MgCl ₂ or ZnCl ₂ Mg ²⁺ or Zn ²⁺ ions diffuse toward the negative (-) reinforcing bar in the concrete along the micro-cracks of the concrete, and are precipitated as Mg(OH) ₂ or Zn(OH) ₂ , which is then deposited on the surface of the corroded reinforcing bar. It is intended to provide an electrochemical electrodeposition device using a galvanized film as an oxidation electrode, characterized in that it fills microcracks.

In addition, it is intended to provide an electrochemical electrodeposition device using a galvanized film as an oxide electrode, characterized in that the current density is 1 to 5 uA/cm ² .

In addition, it is intended to provide an electrochemical electrodeposition device using a galvanized film as an oxide electrode, characterized in that the galvanized film is formed to a thickness of 50 to 100 μm.

In addition, (a) using the electrochemical electrodeposition device as a rectifier, the corroded reinforcing bars in the concrete are made to be negative (-), and the anode is used as anode (+) to apply current at a constant current density to obtain concentrated ions in the electrolyte Precipitating in the form of a compound to fill the inside of the micro-cracks and at the same time coating the surface of the rebar; (b) drying the concrete; to provide a method for repairing concrete micro-cracks and inhibiting corrosion of reinforcing bars using an electrochemical electrodeposition mechanism, characterized in that it comprises.

In addition, between steps (a) and (b), to provide a method for repairing concrete microcracks and inhibiting corrosion of reinforcing bars using an electrochemical electrodeposition device, characterized in that a pH13 NaOH solution is applied along the microcracks.

The electrochemical electrodeposition device using a galvanized film as an oxidizing electrode and a method for repairing concrete micro cracks and inhibiting corrosion of reinforcing bars using the galvanized film as an oxidizing electrode by using an inexpensive galvanized film as an oxidizing electrode instead of expensive titanium, platinum and iridium Economic feasibility can be secured, and if the distribution of micro-cracks is wide, the coating area of the galvanized film can be expanded and used, so it has an advantage over the existing price and effect compared to the existing ones. Since it is repairable, it is possible to repair/reinforce microcracks caused by corrosion of steel bars caused by various offshore structures or snow removal work in winter, and also has a very useful effect that contributes to the extension of the lifespan of structures.

The following drawings attached to this specification illustrate a preferred embodiment of the present invention, and together with the detailed description of the present invention serve to further understand the technical idea of the present invention, the present invention is limited to those described in the accompanying drawings. It should not be construed as limiting.
1 is a diagram showing the operation of an electrochemical electrodeposition apparatus using a zinc coating film of the present invention as an oxidizing electrode.
2 is a side view of an electrochemical electrodeposition device using the zinc coating film of the present invention as an oxidizing electrode.
Figure 3 is a photograph comparing the appearance before and after electrochemical electrodeposition treatment for a specimen having microcracks using the present invention.
FIG. 4 is an enlarged view of a micro-crack portion after the electrodeposition treatment in FIG. 3;

Below, the present invention will be described in detail with reference to the embodiments presented in the accompanying drawings, but the presented embodiments are illustrative for a clear understanding of the present invention, and the present invention is not limited thereto.

Hereinafter, the technical configuration of the present invention according to a preferred embodiment will be described in detail.

1 is a diagram showing the operation of an electrochemical electrodeposition device using a zinc coating film of the present invention as an oxidation electrode, and FIG. 2 is a side view of an electrochemical electrodeposition device using a zinc coating film of the present invention as an oxidation electrode.

An insoluble anode such as Ti (titanium), Pt (platinum), or Ir (iridium) is used as an anode for use in electroplating using electrochemical methods and electromethod (cathode method).

This is to prevent consumption by using precious metals since current flows out from the anode when electroplating or electrocorrosion is performed. Due to this, constant current density is always possible. However, precious metals are very expensive, and the cost increases when they have a large area.

However, in the present invention, electrochemical electrodeposition is performed using an inexpensive zinc coating film as an oxidizing electrode to prevent corrosion of reinforcing bars, thereby securing economic feasibility, repairing microcracks in concrete, and improving the distribution of microcracks. If it is wide, it can be used by widening the coating area of the galvanized film, so the price and effect are superior to the case of using expensive titanium, platinum and iridium as anodes.

As shown in FIGS. 1 and 2, the present invention includes a water tank 10 of a certain size; An electrolyte 20 filled in the water tank 10; an oxidation electrode 30 formed of a galvanized film at the lower outlet of the water tank 10; and a absorbent surface 40 configured to cover the anode 30.

As the electrolyte 20 configured inside the water tank 10, various known electrolytes may be used, and in particular, in the present invention, an electrolyte saturated with MgCl ₂ or ZnCl ₂ may be used.

The galvanized film can be freely adjusted to more than 1m depending on the area where microcracks occur. In addition, it is not easy to measure the galvanized film at a thickness of less than 50 μm, and economical efficiency deteriorates when the thickness exceeds 100 μm, so it is preferable to form a thickness of 50 to 100 μm. If microcracks occur randomly in a large area of a structure, repair/reinforcement can be performed simultaneously by installing several electrodeposition devices.

Absorbent cotton 40 is configured to cover the zinc coating film. increase wettability.

As shown in FIG. 1, the water tank 10 is filled with the electrolyte 20 saturated with ZnCl ₂ or MgCl ₂ , the anode 30 formed of a galvanized film by the rectifier is used as an anode, and the corroded reinforcing bar 60 ) as a cathode, when a current is applied at a constant current density (preferably 1 to 5 uA/cm ² ), the concentrated ions in the electrolyte precipitate in the form of a compound to fill the inside of the micro crack and at the same time coat the surface of the reinforcing bar It repairs cracks with chiro and reduces corrosion of reinforcing bars.

As shown in FIG. 1, about 1 week or less is sufficient when filling micro-cracks distributed over the (1x1)m area of the oxidation electrode 30.

If the area of the galvanized film in the oxidation electrode 30 is increased, it may be shorter than this. Since the electrodeposition current density is very low, even if a relatively soluble anode is used as a counter electrode, its consumption is extremely small.

In addition, even if the galvanized film is completely dissolved and consumed, it can be used by re-coating the galvanized film, and since no precious metal is used as an anode material, it is possible to manufacture a number of electrochemical electrodeposition devices, reducing the processing time required for micro-crack repair. , it is possible to repair microcracks randomly distributed over a large area of a structure.

The treatment time may vary depending on the thickness of the concrete or the density of the micro cracks, but the electrodeposition work can be completed in about 7 days or less. Depending on the difference in electronegativity, the Mg ²⁺ or Zn ²⁺ ions diffuse toward the reinforcing steel, which is the cathode in the concrete, along the micro-cracks, and is precipitated as Mg(OH) ₂ or Zn(OH) ₂ to corrode the reinforcing bar. surface and micro cracks can be filled.

Electrodeposition technology using Zn ²⁺ and Mg ²⁺ ions is uniformly precipitated and coated on the cathode surface (rebar surface) in the form of a compound containing Zn(OH) ₂ and Mg(OH) ₂ as main components.

The precipitate coated on the surface of the reinforcing bar also precipitates between the porous corrosion products of the reinforcing bar inside the micro-cracks. This becomes a physical barrier to suppress the diffusion of dissolved oxygen, reducing the corrosion rate.

Figure 3 is a photograph comparing the state before and after electrochemical electrodeposition treatment for a specimen having microcracks using the present invention, and Figure 4 is an enlarged view of the microcrack portion after electrodeposition treatment in FIG.

As shown in FIG. 3, after generating and growing (Before) microcracks using a small test piece, the results (After) of filling the microcracks by electrodeposition of magnesium are shown.

In addition, as a result of cross-sectional analysis, it was confirmed that micro cracks with a width of about 100 to 200 μm, which had grown due to corrosion of the reinforcing bars, were confirmed to be filled with magnesium by electrochemical electrodeposition treatment. From these experimental results, it is thought that the corrosion rate of the reinforcing bar is rapidly reduced by the electrodeposition treatment, and the microcracks do not grow any more. With these experimental results, in order to reduce the non-uniform current distribution by having a large electrical resistance such as reinforced concrete, ① a low-cost large-area anode is required, and ② in order to repair the unevenly distributed microcracks, as in the present invention The electrochemical electrodeposition device is mobile or requires a large number of electrodeposition devices. If this is connected to a rectifier with multiple channels, numerous micro-cracks can be repaired at the same time.

In the method of repairing concrete micro cracks and suppressing corrosion of reinforcing bars using the electrochemical electrodeposition device of the present invention, first, the electrochemical electrodeposition device is used to make the corroded reinforcing bars 60 in the concrete become negative electrodes (-) using a rectifier, and (30) is applied as an anode (+) and a current is applied at a constant current density to precipitate the concentrated ions of the electrolyte in the form of a compound to fill the inside of the micro crack and simultaneously coat the surface of the reinforcing bar (a).

After this electrodeposition treatment, the reduction rate of dissolved oxygen around the reinforcing bar (O ₂ + 2H ₂ O + 4e → 4OH ^- ) decreases, and accordingly, the corrosion rate of the reinforcing bar (F → F ⁿ⁺ + ne) decreases simultaneously. and the growth of microcracks is impossible or slowed down.

O ₂ + 2H ₂ O + 4e ^- → 4OH ^- (1)

2OH ^- + Zn ²⁺ → Zn(OH) ₂ (2) or 2OH ^- + Mg ²⁺ → Mg(OH) ₂ (3)

During the above steps, Free OH ^- is generated by the reduction reaction of dissolved oxygen (O ₂ + 2H ₂ O + 4e ^- → 4OH ^- ) in the steel bar, which is the cathode, and is diffused by the current flowing out to the anode composed of a zinc coating film. Although Zn(OH) ₂ or Mg( ^OH ) ₂ is precipitated by reacting with Zn ²⁺ or Mg 2+ ions, pH 13 NaOH solution may be flowed or applied along the micro-cracks to accelerate the precipitation reaction.

When concrete is initially created, it is about pH 13, and at this pH, reinforcing bars do not corrode at all and exist in a passive state. And, when the concrete is neutralized, the pH is reduced to about 9 to 10, and at this time, the corrosion rate of the reinforcing steel is accelerated.

Therefore, in the present invention, the pH of the electrodeposition solution can be adjusted to the pH of the initial concrete state by flowing or applying the pH 13 NaOH solution along the micro-cracks, thereby making it easy to precipitate on the surface of the reinforcing bar.

Finally, the concrete is allowed to dry (b).

Drying may be performed by various known methods including natural drying.

The electrochemical electrodeposition device using the galvanized film of the present invention as an oxidizing electrode and the method for repairing concrete micro cracks and inhibiting corrosion of reinforcing bars using the same as described above use an inexpensive galvanized film as an oxidizing electrode instead of expensive titanium, platinum and iridium. Economic feasibility can be secured by using it, and if the distribution of micro cracks is wide, the coating area of the galvanized film can be widened and used. By simultaneously repairing cracks, it is possible to repair/reinforce micro-cracks caused by corrosion of steel bars caused by various offshore structures or snow removal in winter, and have a very useful effect that contributes to the extension of the lifespan of structures.

So far, the present invention has been described in detail with reference to the presented embodiments, but those skilled in the art can make various modifications and variations without departing from the technical spirit of the present invention with reference to the presented embodiments. will be. The present invention is not limited by these variations and modifications, but is limited only by the claims appended below.

10: water tank
20: electrolyte
30: oxidation electrode
40: cotton wool
50: concrete
60: rebar

Claims (7)

A water tank 10 of a certain size;
An electrolyte 20 filled in the water tank 10;
an oxidation electrode 30 formed of a galvanized film at the lower outlet of the water tank 10;
It consists of a; absorbent cotton 40 configured to cover the oxidation electrode 30,
The rebar 60 corroded in the concrete 50 by the rectifier is made to be a negative electrode (-) and the oxidizing electrode 30 is made to be an anode (+), and a current is applied at a constant current density to perform electrochemical electrodeposition An electrochemical electrodeposition device using a characteristic zinc coating film as an oxidizing electrode. The method of claim 1,
The electrolyte 20 is an electrochemical electrodeposition device using a galvanized film as an oxidation electrode, characterized in that saturated MgCl ₂ or ZnCl ₂ . The method of claim 2,
of saturated MgCl ₂ or ZnCl ₂ Mg ²⁺ or Zn ²⁺ ions diffuse along the micro-cracks of the concrete 50 toward the negative electrode (-) reinforcing bar 60 in the concrete 50,
An electrochemical electrodeposition device using a zinc coating film as an oxidation electrode, characterized in that it is precipitated with Mg (OH) ₂ or Zn (OH) ₂ to fill the surface and microcracks of the corroded reinforcing bar (60). The method of claim 1,
An electrochemical electrodeposition device using a zinc coating film as an oxide electrode, characterized in that the current density is 1 to 5 uA / cm ² . The method of claim 1,
An electrochemical electrodeposition device using a zinc coating film as an oxide electrode, characterized in that the zinc coating film is formed to a thickness of 50 to 100 μm. In the method for repairing micro cracks in concrete and inhibiting corrosion of reinforcing bars using the electrochemical electrodeposition device of any one of claims 1 to 5,
(a) Using an electrochemical electrodeposition device as a rectifier, the corroded reinforcing bar 60 in the concrete 50 becomes a negative electrode (-), and the oxidizing electrode 30 is used as an anode (+) to apply current at a constant current density so that the concentrated ions of the electrolyte are precipitated in the form of a compound to fill the inside of the micro-cracks and at the same time coat the surface of the rebar;
(b) drying the concrete (50); a method for repairing concrete micro-cracks and inhibiting corrosion of reinforcing bars using an electrochemical electrodeposition device, characterized in that it comprises. The method of claim 6,
Between steps (a) and (b),
A method for repairing concrete micro-cracks and inhibiting corrosion of reinforcing bars using an electrochemical electrodeposition device, characterized in that the pH13 NaOH solution is applied along the micro-cracks.

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