JP7421279B2 - How to install galvanic anode material - Google Patents

Description

The present invention is a dotted anode type galvanic anode material used in electrochemical corrosion protection methods for concrete structures such as reinforced concrete slabs and box girders constituting elevated roads and bridges, and box culverts buried underground. Regarding the installation method.

For example, there are thick concrete sections with embedded steel materials such as reinforcing bars, such as reinforced concrete slabs and web sections of concrete box girders that make up elevated roads and bridges, box culverts that make up underground structures, etc. In concrete structures, internal steel materials may corrode due to the neutralization of concrete, salt contained in concrete materials, and the effects of flying salt from the outside and antifreeze materials (salt damage), leading to deterioration of the concrete structure. be.

As a countermeasure against corrosion of steel materials such as reinforcing bars, an electrochemical corrosion protection method is known, which prevents corrosion of steel materials such as reinforcing bars (hereinafter referred to as steel materials subject to corrosion protection) by supplying an electric current to the steel materials. Depending on the supply method, it is broadly divided into external power supply method and galvanic (sacrificial) anode method.

In the external power supply method, an insoluble anode made of titanium or the like is installed on the concrete surface or inside the concrete, and a DC power supply is connected between this insoluble anode and the reinforcing bars that form the cathode, and current is supplied from the insoluble anode to the reinforcing bars. Because it allows the amount of current to be adjusted and has excellent long-term corrosion protection, it is often used in electrochemical corrosion protection methods for reinforced concrete structures.

However, this type of electrochemical corrosion protection method using an external power source requires an external power source, its control device, etc., and therefore has the problem of high equipment costs and high maintenance and management costs.

On the other hand, the galvanic anode method installs a galvanic anode made of zinc, aluminum, etc., which has a lower oxidation-reduction potential than the steel to be protected against corrosion, on the concrete surface, and utilizes the potential difference between the galvanic anode and the reinforcing steel. This method supplies current to the reinforcing bars, and although the amount of current generated is small, it can be expected to have a sufficient corrosion prevention effect, and since it does not require an external power source, the installation cost and maintenance cost are low. It is hoped that the anti-corrosion method will be applied to various concrete structures such as concrete floor slabs, concrete box girders, and box culverts.

On the other hand, electrochemical corrosion protection structures for concrete structures are classified into a planar anode system, a linear anode system, and a dot anode system, depending on the placement of the anode in the concrete part where the steel material to be protected against corrosion is buried.

In the planar anode method, an anode material formed in the form of a sheet or net is laid on the surface of the concrete part, and in the linear anode method, multiple grooves are formed on the surface of the concrete part, and linear wires are placed in the grooves. Anode material is embedded (see Patent Document 1). The point anode method is a construction method in which multiple holes are made in concrete depending on the amount of reinforcing steel, an anode is inserted into the hole, the hole is backfilled with cement-based non-shrinkable mortar, etc., and the anode is installed in the concrete. (See Patent Document 2).

Japanese Patent Application Publication No. 2008-169462 JP2017-179526A

In the planar anode method, since the concrete surface is covered with the anode material, it can be expected that the corrosion inhibiting effect will be obtained throughout the entire surface of the concrete. However, since the concrete surface is not visible, it is difficult to confirm the anticorrosion effect from the concrete surface side. Furthermore, the planar anode method is unsuitable when partial corrosion protection is desired because the entire concrete surface is covered with the anode material, including areas that do not require anticorrosion measures. Although the linear anode method is not as bad as the planar anode method, it still has similar problems, such as the embedded part of the linear anode becoming an obstacle when confirming the corrosion protection effect and being unsuitable for partial corrosion protection measures. . Furthermore, in the linear anode method, it is necessary to electrically connect the embedded linear anode materials to each other using conductive wires, which requires a great deal of effort.

In addition, in the linear anode method and point anode method, in order to bury the anode material in the concrete structure and electrically connect it to the steel material to be protected against corrosion, the surface of the concrete is scraped away until the steel material to be protected against corrosion is exposed. This is often done. However, it takes a lot of effort and time to scoop out the concrete and repair the scooped out area. In addition, with this type of buried point anode method, by inserting and burying the galvanic anode material vertically into the surface of the concrete structure, it is possible to penetrate not only the reinforcing bars near the surface of the concrete structure but also deeper into the structure. Although it is expected that a corrosion-preventing effect can be obtained for certain reinforcing bars, it is necessary to drill holes using large-scale equipment such as core drills to embed galvanic anode materials in concrete structures, which is still time-consuming and costly. increases.

Furthermore, although both the planar anode method and the linear anode method are generally applied to the entire surface of a concrete structure, the areas that require cathodic protection are often unevenly distributed, so galvanic anode materials are used. Even if it melts locally and requires partial replacement, it is necessary to replace it over a wide area.

The purpose of the present invention is to provide an electrochemical corrosion protection structure for concrete structures that facilitates the installation of point anode type galvanic anode materials, the repair of concrete after galvanic anode material installation, and the easy replacement of galvanic anode materials. It is an object of the present invention to provide a method for installing a galvanic anode material that can be obtained.

In order to solve the above-mentioned problems, a method for installing a galvanic anode material according to one embodiment of the present invention involves drilling holes in the concrete surface of a concrete structure in which the steel material to be protected against corrosion is buried, in accordance with the position of the steel material to be protected against corrosion. An anchor hole is provided in the concrete surface near the construction hole, an anchor is installed in the anchor hole, a metal connecting member is installed on the bottom of the construction hole so as to be in contact with the steel material to be protected against corrosion, and a plate-shaped A galvanic anode material, a cover that forms a space three-dimensionally surrounding the galvanic anode material by the concrete surface and its own inner surface, a support part that supports the galvanic anode material and the cover, and the anchor. The corrosion protection target is fixed to the anchor by fixing the upper end of an electrochemical corrosion protection unit having a removable upper end and a metal rod electrically connected to the connecting member by a lead wire. The steel material and the galvanic anode material are electrically connected through the connection member, the lead wire, and the metal bar.

According to the galvanic anode material installation method of one embodiment of the present invention, a dot-type galvanic anode material can be installed outside a concrete structure. Therefore, it is possible to reduce the amount of cutting of the concrete part by cutting off only the part necessary to establish continuity with the steel material to be protected against corrosion in the concrete structure, and the installation work of the galvanic anode material. can be done efficiently. Furthermore, by making the galvanic anode material removable from the outside of the concrete structure via a rod, the state of consumption of the galvanic anode material can be visually checked simply by removing the cover, which speeds up wear and tear. Maintenance costs, including replacement work for the electrolytic anode material, can also be kept low. Furthermore, according to this installation method, the position of the electrochemical corrosion protection unit can be determined with a high degree of freedom with respect to the position of the construction hole drilled in accordance with the position of the steel material to be protected against corrosion in the concrete structure. Thereby, for example, the electrochemical corrosion protection unit can be installed even in places where installation is difficult, such as corners and edges of the reinforced concrete floor slab 1, and the degree of freedom in installation can be increased.

1 is a sectional view showing an electrochemical corrosion protection structure of a concrete structure according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing the structure around the construction hole 1H in the electrochemical corrosion protection structure of the concrete structure shown in FIG. 1. FIG. It is a figure which shows the drilling stage of a construction hole in the procedure of the installation method of the galvanic anode material of 1st Embodiment. It is a figure which shows the installation stage of a metal screw in the procedure of the installation method of the galvanic anode material of 1st Embodiment. It is a figure which shows the fixation stage of the attachment bolt to the anchor in the procedure of the installation method of the galvanic anode material of 1st Embodiment. It is a figure which shows the installation stage of a mounting bolt and a galvanic anode material in the procedure of the galvanic anode material installation method of 1st Embodiment. FIG. 3 is a cross-sectional view for explaining an injection method for filling a backfill material. FIG. 8 is a sectional view showing a state in which filling is completed in the injection method of FIG. 7; FIG. 6 is a diagram illustrating a stage in which the backfill material 18 is stored in a surplus state in the cover before installation in the method of filling the backfill material with excess. FIG. 10 is a cross-sectional view showing a state in which filling is completed in the overfilling method of FIG. 9; FIG. 10 is a sectional view showing an example in which a through hole is provided in the galvanic anode material to allow the backfill material to pass through in the overfilling method of FIG. 9; FIG. 7 is a cross-sectional view showing a modification of the method for installing a galvanic anode material according to the present invention. FIG. 2 is a sectional view showing a concrete box girder employing the galvanic anode material installation method according to the present invention.

Next, embodiments according to the present invention will be described based on the drawings.

<First embodiment>
FIG. 1 is a sectional view showing an electrochemical corrosion protection structure of a concrete structure according to a first embodiment of the present invention.
In the figure, a reinforced concrete floor slab 1, which is a concrete structure, has reinforcing bars 2, which are steel materials to be protected against corrosion, arranged at a predetermined distance from a lower surface 1U. On the lower surface 1U of the reinforced concrete floor slab 1, an electrochemical corrosion protection unit 10 of a dotted anode type is installed. This electrochemical corrosion protection unit 10 includes a mounting bolt 11 that is a rod, a galvanic anode material 13, and a cover 15.

The mounting bolt 11 is a rod-shaped member for mounting the electrochemical corrosion protection unit 10 on the lower surface 1U side of the reinforced concrete floor slab 1. The mounting bolt 11 is made of a corrosion-resistant metal material such as aluminum or carbon steel. A thread is provided on the circumferential surface of the entire length of the mounting bolt 11 or a portion thereof. The mounting bolt 11 has an upper end portion 11a that is inserted into and fixed to the anchor 3 installed on the reinforced concrete floor slab 1, and a support portion 11b that supports the galvanic anode material 13 and the cover 15 at positions spaced apart from each other in the rod axis direction. and has.

In the electrochemical corrosion protection structure of the concrete structure of this embodiment, construction holes 1H for connecting reinforcing bars are drilled in the lower surface 1U of the reinforced concrete slab 1, reaching a depth of, for example, the lower end of the reinforcing bars 2 or the vicinity thereof. Ru. A metal screw 5 is screwed into the bottom surface of this construction hole 1J and installed with respect to the reinforcing bar 2 of the reinforced concrete floor slab 1 so that the side surfaces thereof are in contact with each other.

FIG. 2 is an enlarged sectional view showing the structure around the construction hole 1J in the electrochemical corrosion protection structure of the concrete structure shown in FIG. As shown in the figure, a metal screw 21, such as a tapping screw, is screwed into the bottom surface 1K of the construction hole 1J as a metal connection member so that the side surfaces of the reinforcing bar 2 are in contact with each other. More specifically, a screw hole 5 is drilled in the bottom surface 1K of the construction hole 1J in a direction perpendicular to the bottom surface 1U of the reinforced concrete floor slab 1 using a hand drill or the like, and a metal screw 21 is inserted into this screw hole 5. It is screwed in while contacting the side surface of the reinforcing bar 2. A first terminal fitting 25 to which one end of a lead wire 23 is connected is held between the head 21a of the metal screw 21 screwed into the screw hole 5 and the bottom surface 1K of the installation hole 1J. The construction hole 1J is filled with a filler 19 such as non-shrinkable mortar or backfill material.

An anchor 3, such as a female threaded type anchor 3, is installed in the vicinity of the construction hole 1J on the lower surface 1U of the reinforced concrete floor slab 1, and the upper end of the bolt 11 is attached to the hollow cylindrical sleeve 3A, which is the anchor body of the anchor 3. The portion 11a is screwed in. Note that the anchor 3 does not need to be electrically conductive. Then, the other end portion of the lead wire 23, one end of which is connected to the first terminal fitting 25 held between the head 21a of the metal screw 21 and the bottom surface 1K of the construction hole 1J, is inserted into the construction hole 1J. The lead wire 23 is drawn out from the hole 1J downward from the lower surface 1U of the reinforced concrete floor slab 1, and the other end of the lead wire 23 is electrically connected to the mounting bolt 11 via the second terminal fitting 26.

The anchor 3 may be, for example, a female screw type metal anchor 3 driven into the main body. The main body driven type female screw type anchor 3 has a hollow cylindrical sleeve 3A which is an anchor body that is press-fitted into an anchor hole 4 drilled in the lower surface 1U of the reinforced concrete floor slab 1, and one end of the sleeve 3A is provided with an extension portion 3C. The expanded portion 3C is expanded in the radial direction by the plug 3E pushed into the sleeve 3A through the opening 3F formed at the upper end of the sleeve 3A in the axial direction, so that the outer peripheral portion 3B of the expanded portion 3C meets the inner wall surface 4A of the anchor hole 4. dig into it. As a result, the anchor 3 is fixed to the anchor hole 4. Further, the sleeve 3A is provided with a screw hole 3J opened on the other end surface in the axial direction, and the upper end portion 11a of the mounting bolt 11 is screwed into the screw hole 3J, so that the mounting bolt 11 is attached to the anchor 3. Fixed.

As described above, metal screws 5 are installed on the bottom surface 1K of the construction hole 1J with respect to the reinforcing bars 2 in the reinforced concrete floor slab 1 so that their circumferential surfaces are in contact with each other, while the reinforced concrete floor near the construction hole 1J is An anchor 3 is installed on the lower surface 1U of the plate 1, and the upper end 11a of the metal mounting bolt 11 is fixed to the anchor 3, and the metal screw 5 and the mounting bolt 11 are connected to the first terminal fitting 25 and the lead. By electrically connecting them to each other through the wire 23 and the second terminal fitting 26, a corrosion protection current due to the potential difference between the reinforcing bar 2 and the current anode material 13 flows.

Returning to FIG. 1, the galvanic anode material 13 and the cover 15 are supported by the support portion 11b of the mounting bolt 11. The galvanic anode material 13 is a plate-shaped, for example, a disk-shaped member made of a material having a lower oxidation-reduction potential, such as zinc, aluminum, magnesium alloy, etc., than the reinforcing bar 2, which is the steel material to be protected against corrosion. The galvanic anode material 13 has a hole 13a in which the mounting bolt 11 is inserted in a predetermined part such as the center, and the galvanic anode material 13 has a pair of holes 13a in which the mounting bolt 11 is inserted. It is attached using mounting fittings 14A and 14B.

The cover 15 has a cylindrical shape (cylindrical shape or polygonal cylindrical shape) with an open upper side, and has a space in which the galvanic anode material 13 attached to the mounting bolt 11 is three-dimensionally surrounded by the concrete surface 1U and its own inner surface. Form. The cover 15 is removably attached to the lower end portion of the support portion 11b of the attachment bolt 11 using an attachment fitting 14C such as a nut with a washer. The cover 15 is installed with the upper end surface 15a around the upper opening abutting against the lower surface 1U of the reinforced concrete floor slab 1 with the packing material 16 in between.

The galvanic anode material 13 is arranged approximately at the center of a three-dimensional space formed by the inner surface of the cover 15 and the concrete surface 1U, and this space is filled with a backfill material 18. The purpose of the backfill material 18 is to facilitate the dissolution of the galvanic anode material 13 by lowering the resistance near the periphery of the galvanic anode material 13. Note that the backfill material 18 may be made of, for example, a fluid material containing gypsum, bentonite, or the like as a main ingredient. Alternatively, a porous member having water-retaining properties such as a phenol resin continuous foam may be used, in which an electrolyte solution is impregnated and retained.

Note that the construction holes 1J drilled in the lower surface 1U of the reinforced concrete floor slab 1 may be filled with a filler 19 such as non-shrinkable mortar or backfill material, for example, before the cover 15 is attached.

<Construction procedure>
Next, a procedure for installing a galvanic anode material related to the electrochemical corrosion protection structure of a concrete structure according to the present embodiment will be explained using FIGS. 3 to 8.
First, with reference to the design drawing of the reinforced concrete deck slab 1 to be subjected to anti-corrosion construction, the position of the reinforcing bar 2, which is the steel material to be anti-corrosion-protected, in the reinforced concrete deck slab 1 is checked, and the position of the construction hole 1J is determined. Alternatively, the position of the construction hole 1J may be determined by searching for the reinforcing bars 2 using a concrete internal exploration radar.

Next, as shown in FIG. 3, a construction hole 1J is drilled on the lower surface 1U side of the reinforced concrete floor slab 1 using a drill cutter or the like. At this time, the position of the construction hole 1J is determined so that the hole is drilled to a depth that allows the position of the reinforcing bar 2 to be visually observed, and an area where the metal screw 21 can be installed immediately beside the reinforcing bar 2 is secured.

Next, as shown in FIG. 4, a screw hole 5 is drilled in the bottom surface 1K of the construction hole 1J using a hand drill or the like, and a metal screw 21 is screwed into the screw hole 5 and installed. At this time, care should be taken to ensure that the side surfaces of the metal screw 21 and the reinforcing bar 2 are in contact with each other to ensure an electrical connection between the two. Here, a metal screw 21 that is harder than the reinforcing bar 2 is used, and the inner diameter of the screw hole 5 is smaller than the diameter of the metal screw 21 by the thread length, so that when screwing the metal screw 21 into the screw hole 5, Then, the thread of the metal screw 21 is inserted into the inner wall surface of the screw hole 5. This makes the electrical connection between the reinforcing bar 2 and the metal screw 21 more reliable. Conversely, the metal screw 21 may be made of a material having a lower hardness than the reinforcing bar 2, and the thread may be crushed by the reinforcing bar 2 when the metal screw 21 is screwed into the screw hole 5.

Furthermore, when screwing the metal screw 21 into the screw hole 5, the first terminal fitting 25 to which one end of the lead wire 23 is connected is held between the head 21a of the metal screw 21 and the bottom surface 1K of the construction hole 1J. . A second terminal fitting 26 is connected to the other end of this lead wire 23.

Next, as shown in FIG. 5, the construction hole 1J drilled in the lower surface 1U of the reinforced concrete floor slab 1 is filled with a filler 19 such as non-shrinkable mortar or backfill material. Note that this step can be omitted if the construction hole 1J is also filled with the backfill material at the same time when the cover 15 is filled with the backfill material 18.

On the other hand, an anchor hole 4 is drilled in the lower surface 1U of the reinforced concrete floor slab 1 near the construction hole 1J using a hand drill or the like, and the anchor 3 is press-fitted into the anchor hole 4 and installed.

Subsequently, as shown in FIG. 6, the upper end 11a of the mounting bolt 11 is screwed into the screw hole 3J of the sleeve 3A of the anchor 3 to fix the mounting bolt 11 to the anchor 3, and the support portion of the mounting bolt 11 is fixed to the anchor 3. The galvanic anode material 13 is attached to 11b using a pair of upper and lower mounting fittings 14A and 14B such as nuts with washers. The height position at which the galvanic anode material 13 is attached to the mounting bolts 11 is a position lower than the lower surface 1U of the reinforced concrete deck 1, or, considering the filling property of the backfill material 18, the height position where the galvanic anode material 13 is attached is lower than the lower surface 1U of the reinforced concrete deck 1. Appropriately, a height position approximately in the middle of the mounting bolt 11 protruding downward from the top is suitable. That is, if the gap from the lower surface 1U of the reinforced concrete floor slab 1 to the galvanic anode material 13 is too narrow, the backfill material 18 may not be sufficiently filled in the gap.

Next, as shown in FIG. 1, the cover 15 is attached to the support part 11b of the attachment bolt 11 with the attachment fittings 14C, and the cover 15 is installed in the three-dimensional space formed by the lower surface 1U of the reinforced concrete floor slab 1 and the inner surface of the cover 15. Fill with backfill material 18.

As described above, according to the electrochemical corrosion protection structure of a concrete structure and the installation method of the galvanic anode material of the first embodiment, the galvanic anode material 13 of the point anode type is installed outside the reinforced concrete floor slab 1. It can be attached to. As a result, the amount of cutting of the concrete part can be kept low compared to the method of embedding the galvanic anode material in the concrete part of the reinforced concrete slab 1. Specifically, it is sufficient to drill holes in the concrete portion only in the portions necessary to establish continuity with the reinforcing bars 2 in the reinforced concrete floor slab 1. This reduction in the amount of concrete cutting makes it possible to efficiently install an electrochemical corrosion protection unit containing a galvanic anode material. Furthermore, by attaching the galvanic anode material 13 outside the reinforced concrete floor slab 1, it is possible to visually check the wear state of the galvanic anode material 13 due to corrosion protection simply by removing the cover 15. Therefore, compared to a construction method in which the galvanic anode material is embedded in a concrete portion, the galvanic anode material 13 can be replaced quickly, and maintenance costs can be reduced. Furthermore, according to the electrochemical corrosion protection structure of the concrete structure and the installation method of the galvanic anode material of the first embodiment, the distance from the construction hole 1J drilled to bring the metal screw 21 into contact with the reinforcing bar 2 is A galvanic anode material 13 can be placed at the location. Therefore, for example, the electrochemical corrosion protection unit 10 can be installed even in places where installation is difficult, such as corners and edges of the reinforced concrete floor slab 1, and the degree of freedom in installation can be increased.

<How to fill with backfill material>
Next, a method of filling the fluid backfill material 18 into the three-dimensional space formed by the lower surface 1U of the reinforced concrete floor slab 1 and the inner surface of the cover 15 will be described.
There are two methods for filling the fluid backfill material: an injection method and an overfill method.

The injection method is a method in which the backfill material 18 is injected while the cover 15 is temporarily fixed to the support portion 11b of the mounting bolt 11. As shown in FIG. 7, the cover 15 is provided with an injection port 15b in order to inject the fluid backfill material 18 into the cover 15. It is preferable that the injection port 15b be provided, for example, at a portion that becomes the bottom portion when the cover 15 is completely attached. A nozzle 17 for supplying backfill material is inserted into the injection port 15b, and the backfill material 18 is injected (press-fitted) into the cover 15 through the nozzle 17.

The backfill material 18 is injected into the cover 15 so that the air E in the space inside the cover 15 is replaced with the backfill material 18, and the backfill material 18 is injected into the cover 15 so that the air E is smoothly discharged outside the cover 15. When pouring the material 18, it is desirable to secure an appropriate gap G between the lower surface 1U of the reinforced concrete floor slab 1 and the end surface of the packing material 16 adhered to the end surface 15a around the upper opening of the cover 15.

As shown in FIG. 8, when the inside of the cover 15 is almost filled with the backfill material 18, the backfill material 18 overflows from the above-mentioned gap G, so this state is regarded as a state in which the filling of the backfill material 18 is completed, and the backfill material 18 is filled with the backfill material 18. After completing the injection of the fill material 18, the nozzle 17 is removed and the injection port 15b is closed with a lid or the like.

After that, the cover 15 is lifted up to a height where the end surface of the packing material 16 bonded to the upper end surface 15a around the opening hits the lower surface 1U of the reinforced concrete floor slab 1, and the height position of the cover 15 is fixed with the mounting bracket 14C. . This completes the installation of the electrochemical protection unit 10.

FIGS. 9 and 10 are diagrams for explaining the overfilling method.
As shown in FIG. 9, for example, before attaching the cover 15 to the mounting bolts 11, a space (galvanic anode material (excluding the space occupied by 13).

Next, as shown in FIG. 10, the support part 11b of the mounting bolt 11 is inserted into the hole (not shown) provided on the bottom surface of the cover 15, and the cover 15 is lifted toward the lower surface 1U of the reinforced concrete slab 1. . When the cover 15 approaches the lower surface 1U of the reinforced concrete floor slab 1, the surplus of the backfill material 18 in the cover 15 begins to overflow from the gap G between the cover 15 and the lower surface 1U of the reinforced concrete floor slab 1. Therefore, at the time when the end surface of the packing material 16 around the opening of the cover 15 hits the lower surface 1U of the reinforced concrete deck 1, a backfill is filled in the three-dimensional space formed by the lower surface 1U of the reinforced concrete deck 1 and the inner surface of the cover 15. The material 18 is now filled. Finally, as shown in FIG. 1, the height position of the cover 15 is fixed to the support portion 11b of the mounting bolt 11 using the mounting bracket 14C. This completes the installation of the electrochemical corrosion protection unit 10 filled with the backfill material 18.

In addition, as shown in FIG. 11, the backfill material 18 is attached to the galvanic anode material 13 so that the backfill material 18 sufficiently wraps around the space between the upper surface of the galvanic anode material 13 and the lower surface 1U of the reinforced concrete deck 1. A through hole 13b may be provided for passing through.

According to this overfilling method, the backfill material 18 can be filled in a shorter time than the above-described injection method. In addition, the work of putting the backfill material 18 into the cover 15 in a surplus state can be performed on the ground facing downward. Therefore, compared to the above-mentioned injection method, this method has excellent work efficiency, and there is no need to provide an injection port in the cover 15 or a lid to cover the injection port, so that cost reduction can be expected.

<Modified example>
Next, a modification of the above embodiment will be shown.
FIG. 12 is a sectional view showing a modification of the method for installing a galvanic anode material according to the present invention.
This modification is an example in which metal clip members 6 are used to fix the mounting bolts 11 to the reinforced concrete floor slab 1 and to electrically connect them to the reinforcing bars 2.

The clip member 6 can be manufactured from a spring steel material such as a spring steel plate by bending or the like, and consists of a base 6a and a pair of legs 6b and 6c facing each other. The base 6a has a substantially cylindrical cross-sectional shape corresponding to the outer peripheral shape of the reinforcing bar 2, and is hooked to the reinforcing bar 2 by fitting the reinforcing bar 2 inside. The pair of legs 6b and 6c are portions extending from the base 6a, and hold the upper end 11a of the mounting bolt 11 from both sides. In order to fit the reinforcing bar 2 inside the base 6a, the legs 6b and 6c are pushed outward from the inside and opened when passing between the legs 6b and 6c, so that the reinforcing bar 2 fits inside the base 6a. The legs are closed by the elastic restoring force and the reinforcing bars 2 are held within the base 6a. Thereafter, the upper end portion 11a of the mounting bolt 11 is inserted between the pair of legs 6b and 6c in the closed state, and they are fixed to each other by welding or adhesion.

Thereafter, in the same manner as the installation method of the first embodiment, filling of the filling material into the construction hole 1M, attachment of the galvanic anode material 13 and cover 15, and filling of the backfill material 18 are performed to complete the corrosion protection unit. Installation work is complete.

In this modification, in order to fit the reinforcing bar 2 inside the base 6a of the clip member 6, the clip installation space 7 is created by scooping out the concrete part around the entire circumference of the reinforcing bar 2 exposed at the back of the construction hole 1M. need to be formed.

The electrochemical corrosion protection structure of a concrete structure according to the present invention is not limited to the above-mentioned reinforced concrete slab example, but can be applied to, for example, concrete box girders, box culverts buried underground, and other concrete structures. It can also be applied to

FIG. 13 is a cross-sectional view showing an example of implementation in which the electrochemical corrosion protection structure of a concrete structure according to the present invention is adopted for a concrete box girder.
In this construction example, since the reinforcing bars 2 on the lower side of the lower slab 32 of the concrete box girder 30 and the reinforcing bars 2 on the outside of each web 33 and 34 are steel materials subject to corrosion protection, the lower side of the lower slab 32 and each web Electrically independent electrochemical corrosion protection units 10 are installed on the outer surfaces of 33 and 34, respectively.
In addition, when the reinforcing bars on the upper side of the lower deck 32, the reinforcing bars inside each web 33, 34, or the reinforcing bars 2 of the upper deck 31 are the steel materials to be protected against corrosion, the placement positions of the reinforcing bars 2, which are the steel materials to be protected against corrosion, are similarly determined. The electrochemical corrosion protection unit 10 may be installed on the concrete surface side closer to the concrete surface.

Although the case where the reinforcing bars 2 are the steel material to be protected against corrosion has been described above, the present invention can also be applied to cases where the steel material to be protected against corrosion is other steel materials such as steel frames in concrete structures.

1...Reinforced concrete floor slab 1J...Construction hole 2...Rebar 3...Anchor 4...Anchor hole 10...Electrochemical corrosion protection unit 11...Mounting bolt 11a...Upper end 11b...Support part 13...Galvanic anode material 15...Cover 18...Back Fill material 21...Metal screw 23...Lead wire

Claims (3)

Drilling a construction hole in the concrete surface of the concrete structure in which the steel material to be protected against corrosion is buried, in accordance with the position of the steel material to be protected against corrosion,
A metal connecting member is installed in the construction hole drilled in the concrete surface so as to be in contact with the steel material to be protected against corrosion,
An anchor hole is provided in the concrete surface at a position spaced apart from the construction hole, and the anchor is installed in the anchor hole,
A metal bar to which a plate-shaped galvanic anode material is attached is electrically connected to the metal connecting member installed in the construction hole through a lead wire, to the anchor installed in the anchor hole. , the galvanic anode material is fixed at a position spaced outward from the concrete surface;
After the metal bar is fixed, it forms a cylindrical or polygonal cylinder shape with an opening on one end surface, and with the one end surface abutted against the concrete surface, it is placed between the concrete surface and its own inner surface. A method for installing a galvanic anode material, comprising: attaching a cover configured to form a three-dimensional space for accommodating the galvanic anode material to the metal bar. A method for installing a galvanic anode material according to claim 1, comprising:
The connecting member is a metal screw. Method for installing a galvanic anode material. A method for installing a galvanic anode material according to claim 1, comprising:
The connecting member is a metal clip member. A method for installing a galvanic anode material.

Images