JP2002105677A - Electrolytic corrosion protection device of concrete structure, and the concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic corrosion protection device which is less effective on a concrete structure and easy in construction thereof, and to provide the concrete structure. SOLUTION: This electrolytic corrosion protection device of the concrete structure comprises an electrolytic corrosion protection electrode holding means which holds at least one electrolytic corrosion protection electrode and is fixed in a concrete directly or via other members, a bar-like protective member for the electrolytic corrosion protection electrode which is disposed opposite to at least a steel side of the electrolytic corrosion protection electrode, and an electrolytic corrosion protection current feeding means to the electrolytic corrosion protection electrode and a steel member in the concrete.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing corrosion of a concrete structure and a concrete structure.
In particular, the present invention relates to an anticorrosion apparatus and a concrete structure in which an anticorrosion electrode is disposed near a steel material such as a reinforcing bar in a new or existing concrete structure.

[0002]

BACKGROUND OF THE INVENTION Reinforcing bars in concrete structures do not normally corrode in an alkaline environment in concrete. However, in concrete structures located along the coast and structures that come in contact with water containing halides such as calcium chloride and salt sprayed to prevent freezing, the halides penetrate into the concrete, and Corrosion may occur. When the reinforcing bar is corroded, the volume of the reinforcing bar is expanded by the generated hydroxide of iron or the like, and stress acts on surrounding concrete to cause cracking of the concrete. If water containing a halide such as seawater infiltrates further due to cracks generated in concrete, corrosion of the reinforcing bar proceeds, and there is a risk that serious problems such as falling of the concrete structure may occur.

As means for preventing corrosion of steel structures such as reinforcing bars in concrete structures, an electrode having an electrode catalyst coating formed on the surface of a corrosion-resistant metal such as titanium is mounted on the surface of the concrete structure, and the reinforcing bars are connected to the cathode. An electrolytic protection method for supplying a corrosion protection current to a reinforcing bar is known. The method of cathodic protection of steel bars and the like is to prevent corrosion from occurring by changing the potential of steel bars in a corrosive environment to a base direction that does not cause corrosion. Various installation methods are known. For example, the surface of the concrete is subjected to ground treatment using sand blasting or the like, and the net-like cathodic protection electrode is installed on the concrete surface using a fixing jig. After spot welding was performed to secure electrical continuity between the electrodes for corrosion protection, the entire surface of the anode was covered with a cement-based overlay material on the mesh-like electrode for corrosion protection fixed to the concrete surface. However, there was a problem that the dead load of the structure after the construction was increased by covering with the overlay material.

Further, it is necessary to coat the mortar such as an overlay material on the anticorrosion target in several times to a predetermined thickness so as to sufficiently secure the adhesive strength between the mortar and the concrete frame. Work by skilled technicians is required. In addition, a method is known in which grooves are cut at predetermined intervals using a concrete cutter or the like in order to embed the strip-shaped cathodic protection electrode on the concrete surface. In this method, the strip-shaped cathodic protection is fixed to the cut grooves, the respective cathodic protection electrodes are connected by a current distribution member, and are electrically integrated in the same circuit, and then the grooves are filled with cement mortar. are doing.

[0005] Further, in a severe environment such as directly receiving a splash of seawater or the like, a mold is installed in a groove and a cement-based filler is injected. However, when constructing an existing structure, it is necessary to remove the groove for embedding the belt-shaped anode on the concrete surface by cutting it with a concrete cutter or the like. It is necessary to provide a groove for burying the electrode for cathodic protection. The strip-shaped cathodic protection electrode needs to be provided with grooves at predetermined intervals so as to uniformly supply a cathodic protection current to the steel material in the target structure, and the cathodic protection electrode needs to be installed, and this operation requires time. In addition, when the cover thickness of the concrete on the reinforcing bar is small, there is a risk of short-circuiting between the electrode for cathodic protection and the reinforcing bar, so that the construction becomes impossible.
In addition, there is a possibility of short-circuiting with the binding wire used to bind the reinforcing bars embedded in the concrete, and there is a problem that it is necessary to check the insulation between the electrode for cathodic protection and the reinforcing bars at all times. there were.

There is also known a method in which a hole having a predetermined diameter and depth is formed in a concrete structure by a vibration drill or the like, and an electrode for preventing corrosion is inserted into the hole. In this method, after filling the inside of the hole with the backfill, the electrode rod for cathodic protection is inserted into the hole, each electrode rod for cathodic protection is connected with a titanium wire or the like, and the head of the electrode rod for cathodic protection and the titanium wire are grooved. And backfilled with compounding mortar or the like. However, in this method, it is necessary to provide a large number of installation holes in order to bury a large number of electrode electrodes for cathodic protection. Further, since the electrode for cathodic protection is inserted from the concrete surface into the concrete, there is a danger of contact with the reinforcing steel in the concrete.
The work had to be performed while checking whether the book was in contact with the rebar, and it took time to install the anode. Further, when the cover thickness of the concrete on the reinforcing bar is smaller than the length of the electrode bar for cathodic protection, it is impossible to install the electrode bar for cathodic protection.

Further, in order to uniformly supply the anticorrosion current, the distance between the tip of each inserted electrode rod for cathodic protection and the reinforcing bar becomes a problem. It was necessary to investigate the arrangement of the reinforcing steel inside using a radar or the like, and to find the optimal position of the electrode for cathodic protection.

Therefore, in order to solve these problems, a steel material located near a surface of the concrete to be anticorrosion is exposed, and after a predetermined interval is provided from the steel material, a cathodic protection electrode is arranged. There has been proposed a method of casting concrete to cover a steel material and an electrode for cathodic protection. Japanese Patent Laid-Open No. 7-90643 discloses a reinforced concrete body having an anticorrosion electrode, in which an electrode for anticorrosion is arranged in a formwork so as not to come into contact with a reinforcing bar when a concrete structure is newly installed, and then the concrete is driven into the electrode. Has been proposed.

FIG. 6 is a view for explaining an apparatus for protecting a concrete structure from an electrode for protecting a house in which an electrode for protecting the house is provided close to a reinforcing bar. In the concrete structure, the cathodic protection device 1 has a steel member 3 such as a reinforcing bar in a concrete structure 2 having a cathodic protection member 4 made of an electrically insulating material attached thereto. The anticorrosion electrode 5 is fixed by fixing means 6, and an anticorrosion current is supplied between the electrocorrosion protection electrode 5 and the reinforcing bar 3 by a current supply means 7, thereby performing the anticorrosion.

However, at the time of placing concrete, vibration is applied to the concrete using a vibrator so that the concrete is uniformly filled. Therefore, the electrode may be deformed by the vibrator, or a specific portion of the electrode 5 may be deformed by impact due to the aggregate 8 contained in the concrete at the time of casting. As a result, there is a possibility that the electrode for cathodic protection is cut or comes into contact with the steel material 3 such as a reinforcing bar. When such a situation occurs, there is a problem that the electrode embedded in the concrete cannot exhibit the function as the cathodic protection electrode.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a construction method for realizing the electrolytic protection of steel of concrete structures, regardless of existing or new construction, without attaching an electrode to the concrete surface. It is an object of the present invention to provide an electric anticorrosion device and a concrete structure in a concrete structure having good properties and a large anticorrosion effect.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for protecting a concrete structure from corrosion, in which at least one electrode for protection against corrosion is held and fixed to steel in concrete directly or via another member. Electrode protection electrode holding means, at least a bar-shaped protection member for an electrode for electrode protection provided on the side opposite to the steel material side of the electrode for protection against corrosion, and a means for supplying the electrode for protection against corrosion and current for preventing corrosion of steel in concrete The problem can be solved by an anticorrosion device for a concrete structure having the following. Further, in the concrete structure, at least one electrode for cathodic protection is held,
Concrete holding means for holding an electrode for cathodic protection which is fixed directly or via another member to steel material in concrete, and at least a bar-shaped protection member for electrode for cathodic protection which is arranged on the side opposite to the steel material side of the electrode for cathodic protection. The problem can also be solved by using a structure.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cathodic protection device according to the present invention arranges a cathodic protection electrode at a predetermined distance from a steel material in a concrete structure, regardless of whether the structure is new or repaired. In this case, damage to the cathodic protection electrode or contact between the cathodic protection electrode and steel is prevented, and repair of concrete structures, etc. can be performed by performing cathodic protection on steel in concrete structures. This makes it possible to maintain the initial performance for a long period of time without performing it.

The present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an apparatus for preventing catastrophic corrosion of a concrete structure according to the present invention. FIG. 1 (A) is a side view of a reinforcing bar on which electrodes for cathodic protection are arranged, and FIG. 1
FIG. 3A is a partially enlarged cross-sectional view taken along line AA ′ in FIG. In the cathodic protection device 1 of the present invention, the cathodic protection electrode holding means 4 is disposed at a predetermined interval on a steel material 3 such as a reinforcing bar disposed inside the concrete structure 2. Further, an electrode holding portion 9 for holding the electrode for protecting the cathodic protection at a desired interval from the steel material to be protected is formed in the electrode holding means for cathodic protection 4, and the electrode holding portion has at least one electric protection member. The edible electrode 5 is provided, and an erosion protection current is supplied from the current supply means 7 between the erosion protection electrode 5 and the steel material 3.

Protective rods 10 for protecting the electrodes are provided above and below the cathodic protection electrode 5 in parallel with the electrodes.
The electrode holding portion is provided with an opening 11 for a protection rod. This prevents vibrations from being applied at the time of placing concrete, deformation of the cathodic protection electrode by the aggregate 8 due to the flow of the cast concrete, and contact of the cathodic protection electrode with steel. You. Also, the example in which the protection rod 10 is disposed on both sides of the cathodic protection electrode has been described. However, the protection rod 10 provided on both sides increases the function of the protection rod. May be used.

The electrode holding means for cathodic protection is 50 mm to 3 mm.
It is preferable to arrange them at intervals of 00 mm. Further, any material may be used for the cathodic protection electrode holding means 4 as long as it is a non-conductive material, but it is preferable to use a synthetic resin having high corrosion resistance such as polyvinyl chloride, polypropylene, polyethylene, and nylon. As the protective rod, the same material as that of the material for the cathodic protection electrode holding means 4 can be used. The distance between the protection rods is 5 mm to 1 mm.
The diameter of the protection rod is preferably 2 mm to 5 mm.

In the example shown in FIG. 1, the electrode protection means 4 is attached to the steel material 3 by manufacturing the electrode protection means 4 from a flexible insulating material. By providing the lower part with the openable and closable opening 12, the lower part can be easily attached to an existing steel material with the lower part opened. An electrode holding opening 13 is formed in the electrode holding portion 9 of the cathodic protection electrode holding means 4. Although the strip-shaped cathodic protection electrode can be inserted perpendicularly to the surface of the electrode holding opening 13, even if a long strip-shaped electrode is formed by forming the electrode insertion port 14 on the side surface of the electrode holding portion. Electrodes can be easily inserted.

A current distribution member is connected to the cathodic protection electrode 5 so that a cathodic protection current is supplied uniformly. As the current distribution member, an arbitrary one such as an electric wire is used as long as it has conductivity. However, the current distribution member may be held by a holding unit similar to the cathodic protection electrode holding unit. In particular, in the case where a thin film-forming metal plate such as titanium, a bar, or a base material such as an expanded metal is used as a current distribution member, an insulating thin film is formed on the surface when an anode current is applied. Therefore, it is not necessary to cover with an insulating material, but it is preferable to protect the electrode for cathodic protection from impact such as casting concrete as well as protection of the electrode for cathodic protection.
In addition, the electrode 5 for cathodic protection is formed by forming an electrode catalyst coating containing a platinum group metal or a self-metal group metal oxide on a thin film-forming metal plate such as titanium, a bar, or a base material such as an expanded metal. Can be used.

FIG. 2 is a view for explaining an example of the electrode holding means for cathodic protection. FIG. 2A is a perspective view showing a state before inserting the electrode for electrode protection, and FIG. 2B is a front view of the electrode protection means. The electrode protection means 4 shown in FIG. 2 has an electrode holding opening 13 which is long in the height direction of the electrode protection means 4 attached to the steel material 3. The electrode holding opening 13 has an electrode insertion port. After attaching the electrode 4 to the steel material 3, the strip-shaped electrode for electrode protection can be easily inserted. It is preferable to provide an opening 15 in the electrode protection means 4. By providing the opening 15, a current passage is formed, so that the influence on the current distribution due to the installation of the cathodic protection electrode holding means can be reduced.

The protection unit 4 is provided with an opening 11 for a protection rod, into which the protection rod 10 is inserted.
The smaller the distance between the protection rods 10 for protecting the cathodic protection electrode 5 is, the larger the protection function against the impact of aggregates and the like becomes. Therefore, it is preferable that the distance a between the protection rods 9 closer to the steel material 3 is greater than the distance b between the protection rods 9 farther from the steel material.
In FIG. 2, four protection rods 9 are provided, but more protection rods 9 may be provided.

FIG. 3 is a view for explaining another example of the electrode holding means for cathodic protection. FIG. 3A is a perspective view showing a state before an electrode for preventing corrosion is inserted, and FIG. 3B is a front view of the electrode protection means. The electrode protection means 4 shown in FIG. 3 is an electrode holding opening 1 long in a direction perpendicular to the height direction of the corrosion protection means 4 attached to the steel material 3.
3, the electrode holding opening 13 has an electrode insertion opening 14, and after the cathodic protection electrode holding means 4 is attached to the steel material 3, the strip-shaped cathodic protection electrode is easily inserted. be able to.

In addition, the cathodic protection electrode holding means 4 is provided with an opening 15 which is long in the height direction. By increasing the area of the opening 15 in this manner, the influence on the current distribution due to the provision of the cathodic protection electrode holding means 4 can be reduced. In addition, the protection unit 4 is provided with an opening 11 for a protection rod, into which the protection rod 10 is inserted. Protective rod 1 for protecting cathodic protection electrode 5
Since the interval of 0 may adversely affect the current distribution, the interval a between the protection rods 10 on the side closer to the steel material 3 may be different.
Is preferably larger than the distance b between the protection rods 10 on the side far from the steel material. Also, in FIG. 3, four protection rods 10 are provided, but more protection rods may be provided.

FIG. 4 is a view for explaining another example of the electrode holding means for cathodic protection. FIG. 4 (A) is a perspective view showing a state before the electrode for electrode protection is inserted, and FIG. 4 (B) is a front view of the electrode protection means. The electrode protection means 4 shown in FIG. 4 has a laterally long electrode holding opening 13, and the electrode holding opening 13 has an electrode insertion opening 14. After attaching to the steel material 3, the strip-shaped electrode for cathodic protection can be easily inserted. In addition, the protection unit 4 is provided with an opening 11 for a protection rod, into which the protection rod 10 is inserted.

Since the distance between the protection rods 10 for protecting the cathodic protection electrode 5 may adversely affect the current distribution, the distance a between the protection rods 10 on the side closer to the steel material 3 is larger than that on the side farther from the steel material. It is preferable that the distance be larger than the distance b between the protection rods 10. Also, in FIG.
Although four are provided, more may be provided. In the case where the distance between the electrodes is reduced when the cathodic protection electrode holding means 4 shown in FIG. 4 is attached to a steel material, the cathodic protection electrode holding means 4 is attached to a fixing jig attached to the steel material by a binding band or the like. May be.

FIG. 5 is a perspective view for explaining a method of attaching the electrode holding means for corrosion protection to a steel material. FIG. 5 (A)
In order to fix the cathodic protection electrode holding means 4 to which the cathodic protection electrode 5 and the protection rod 10 are attached to the steel material 3, a fixing auxiliary rod 16 is provided on the cathodic protection electrode holding means 4 and fixed by the binding band 17. Shows how to do it. As the binding band fixed to the steel material, any material can be used as long as it is an insulating member such as a synthetic resin such as polyethylene and nylon, but if the steel material surface is covered with the binding band, the passage of the anticorrosion current is prevented. Therefore, it is preferable to use a small amount of the binding band. FIG. 5B shows a method in which a vertically long opening 15 is provided in the sacrificial electrode holding means 4 to which the sacrificial electrode 5 and the protection rod 10 are attached, and the opening 15 is fixed to the steel material 3 through the binding band 17. Indicates that
Although the fixing characteristics of the electrode protection means 4 are slightly inferior to those of FIG. 5 (A), it is not necessary to provide the fixing auxiliary rod 16 in the electrode protection means 4, so that the manufacturing is easy. In addition, by providing an opening having a large opening area, the influence on the current distribution is reduced.

FIG. 5 (C) shows a state in which the cathodic protection electrode holding means 4 to which the cathodic protection electrode 5 and the protection rod 10 are attached is fixed to a fixing jig 18 fixed to the steel material 3 using a binding band 17. is there. In the method shown in FIG. 5C, even when the shape and structure of the portion to be fixed are not constant, various shapes and structures are prepared as the fixing jig 18 so that the anticorrosion electrode holding means can be provided. Since it becomes possible to arrange the electrode held at a predetermined distance from the steel material to be anticorrosion, when repairing the existing concrete structure,
This is a particularly effective method.

[0027]

According to the cathodic protection device of the present invention, when the cathodic protection electrode is arranged close to the steel material in the concrete structure, the contact between the steel material and the cathodic protection electrode, the cutting of the cathodic protection electrode, and the like can be achieved. It is possible to easily obtain an anticorrosion device for a concrete structure having high reliability.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an apparatus for protecting a concrete structure from corrosion according to the present invention.

FIG. 2 is a diagram for explaining an example of an electrode unit for holding a cathodic protection electrode;

FIG. 3 is a diagram illustrating another example of the electrode holding means for cathodic protection.

FIG. 4 is a view for explaining another example of the electrode holding means for cathodic protection.

FIG. 5 is a perspective view for explaining a method of attaching an electrode for preventing corrosion to a steel material.

FIG. 6 is a view for explaining an apparatus for protecting a concrete structure from an electrode for protecting a catastrophic electrode arranged in the vicinity of a reinforcing bar;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electro-corrosion protection device, 2 ... Concrete structure, 3 ... Steel material, 4 ... Electro-corrosion protection electrode holding means, 5 ... Electro-corrosion protection electrode, 6 ... Fixing means, 7 ... Current supply means, 8 ... Aggregate, 9 ...
Electrode holding part, 10: protection rod, 11: opening for protection rod, 12
... Openable and closable opening, 13 ... Electrode holding opening, 14 ... Electrode insertion opening, 15 ... Opening, 16 ... Fixing auxiliary rod, 17 ... Bundling band, 18 ... Fixing jig

Claims (2)

[Claims] 1. An apparatus for protecting a concrete structure from corrosion, comprising: at least one electrode for preventing corrosion, which is fixed to a steel material in concrete directly or via another member; A concrete structure comprising a rod-shaped protection member for an electrode for corrosion protection disposed on the side opposite to the steel material side of the electrode for protection against corrosion, and a means for supplying the electrode for protection against corrosion and a current for preventing corrosion of steel in concrete. Cathodic protection equipment. 2. A concrete structure for holding at least one electrode for protection against corrosion, wherein said means for holding electrode for protection against corrosion is fixed to a steel material in concrete directly or via another member. A concrete structure comprising a bar-shaped protection member for a cathodic protection electrode disposed on a side opposite to a steel material side.