JPH11200642A - Demolishing method for reinforced concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently facilitate the demolition of a concrete with a relatively slight work. SOLUTION: In a demolishing method, a reinforcing bar 2 is used as a positive electrode and a negative electrode connected to the surface of a concrete 1 to carry a DC current thereto and then a reinforced concrete structure is demolished. In this case, a demolition area R is previously separated into small blocks 9 at random, the one-side opening of a container formed with an electric insulator is faced to the small block 9 side to be mounted on the peripheral sides of the small blocks 9, a wire gauze is inserted into the container and oxidation promoter is filled therein to form a negative electrode, so that a DC current can be carried thereto to make a concrete in the negative electrode mounted area deteriorate for dismantling and carrying out the concrete in the small blocks 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dismantling a reinforced concrete structure, and more particularly to a method for disassembling the reinforced concrete structure by passing a weak current between the reinforcing bar and the concrete to deteriorate the concrete.
Rather than installing the cathode over the entire surface of the disassembly area, the reinforced concrete structure separates the disassembly area into small blocks, degrades the concrete around the small blocks, and removes and transports the concrete for each small block. It relates to a method of dismantling an object.

[0002]

2. Description of the Related Art Conventionally, as a method for dismantling a reinforced concrete structure of this kind, a method disclosed in Japanese Patent Application Laid-Open No. 52-101834 is known. Thus, in the method of dismantling a reinforced concrete structure described in the publication, a reinforced concrete is impregnated with an aqueous solution of sodium chloride or calcium chloride in advance, an anode is connected to the reinforcing steel, and a layered metal is further applied to the surface of the concrete. This method is to disassemble the reinforced concrete structure after installing and connecting a cathode to the electrodes and applying a weak current of about several mA / cm ² between both electrodes.

According to this method, the reinforcing bar is oxidized and expanded by the electric current, and the reinforcing bar is separated from the concrete and a crack is generated inside the concrete, so that the concrete is easily crushed. The reason that the reinforced concrete is impregnated with the aqueous sodium chloride solution or the aqueous calcium chloride solution in advance is to promote the oxidation of the reinforcing steel.

[0004] The applicant of the present application has already filed an application for a method of dismantling such a reinforced concrete structure as Japanese Patent Application No. 8-061356. In the invention according to this prior application, an anode is connected to a reinforcing bar, a conductive putty is applied to a wire mesh on a concrete surface to form a flat plate, and the flat plate extends over the entire area of the dismantling area of the reinforced concrete structure. Attached to the cathode.

[0005]

In the above prior art, as a means for previously impregnating a reinforced concrete with an aqueous solution of sodium chloride or calcium chloride, a cloth, cotton or the like impregnated with the aqueous solution is attached to the concrete surface for about one week. However, according to this method, since the water on the cathode side moves to the anode side due to energization, sufficient water cannot be maintained on the cathode side, and therefore, the interface resistance between the cathode plate and the concrete surface is reduced. As a result, the energizing current decreases and the intended purpose cannot be achieved effectively. Further, since the water must always be supplied to the cathode side during energization, the actual work becomes extremely complicated.

In the invention according to the above-mentioned prior application, a steel material such as a form separator may be embedded in the vicinity of a concrete surface in contact with a reinforcing bar in a dismantling area.
The energization causes a short-circuit phenomenon, which may significantly reduce the deterioration efficiency of the concrete with respect to the amount of energization. Further, similarly to the above-described conventional example, the current on the cathode side moves to the anode side due to energization, and the water content on the cathode side becomes insufficient, and the interface resistance between the cathode plate and the concrete surface increases. Therefore, in order to reduce the interface resistance, it is necessary to supply sufficient water to the cathode plate. However, since the water retention capacity of the cathode flat plate of this prior application is limited, if the current is applied for a long period of time, the cathode flat plate dries, the current flow resistance increases, and the current flow decreases. Therefore, water supply during energization is required. Furthermore, the calcium ions in the concrete are eluted to the cathode side when energized, and are precipitated as calcium carbonate. However, the calcium carbonate adheres to the cathode plate, the water retention capacity is reduced, and the deterioration efficiency of the concrete with respect to the amount of electricity is reduced. Is extremely bad.

The present invention has been made in view of the above-mentioned deficiencies of the prior art and the above-mentioned problems of the prior art, and has a reinforcing member of a reinforced concrete structure used as an anode, a cathode connected to the concrete surface to supply a direct current, and In a method of dismantling a reinforced concrete structure which is intended to deteriorate concrete of a product, the dismantling work can be carried out with relatively small work, and the deterioration of the concrete can be efficiently promoted. A technical problem to be solved arises, and an object of the present invention is to solve the problem.

[0008]

Means for Solving the Problems The present invention has been proposed to achieve the above object, and has a reinforcing bar as an anode,
In the method of dismantling a reinforced concrete structure after connecting a cathode to a concrete surface and applying a DC current thereto, the dismantling area is separated into arbitrary small blocks in advance, and an electric insulator is provided around the small blocks. One side open part of the formed container is mounted facing the small block side, and further,
A metal mesh is inserted into the container and an oxidation promoter is filled to form a cathode, and the direct current is applied to deteriorate the concrete at the cathode mounting site, thereby removing and carrying out the concrete for each small block. In the method of dismantling a reinforced concrete structure formed so that it can be formed, and using a reinforcing bar as an anode, connecting a cathode to the concrete surface and passing a direct current, and then dismantling the reinforced concrete structure, It is separated into arbitrary small blocks in advance, a plurality of holes are drilled from the concrete surface in the vicinity of the reinforcing bar in the small blocks, a steel pipe having a large number of small holes is inserted into each of the holes, and the steel pipe is oxidized. Filling the accelerator to form a cathode, and energizing the direct current to degrade the concrete at the cathode mounting site, thereby reducing the concrete for each small block. 3. The method for dismantling a reinforced concrete structure according to claim 2, wherein the method for dismantling a reinforced concrete structure formed so as to be able to be removed and carried out, and the method for dismantling a reinforced concrete structure according to claim 2, wherein the steel pipe is formed in a T-shape by connecting a transparent pipe to a rear end thereof. To provide.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described in detail with reference to FIG. In the figure, reference numeral 1 denotes a concrete of a reinforced concrete structure.
Reinforcing bars 2, 2,... As reinforcing bars are buried vertically and horizontally. When dismantling a part of the reinforced concrete structure, as shown in FIG. 1, a dismantling area R is set, and the periphery of the dismantling area R is marked, and a small concrete cutter or the like is placed on the marking. Make a cut 3. The cut 3 may be about 2 to 3 cm. Cut 3
Prevents a crack caused by energization described later from spreading outside the disassembly region. After that, the position of the reinforcing bar 2 is detected by a reinforcing bar detector or an RC radar. The reinforcing bar 2 serves as an anode in the present invention. Therefore, as shown in FIG. 5, two holes 4, 4a are drilled in the concrete 1 immediately above the detected reinforcing bar 2 so as to reach the reinforcing bar 2, facing one another, and as shown in FIG. A welding rod 5 is inserted into the hole 4 to bring the tip of the welding rod 5 into contact with the reinforcing bar 2, and a steel rod 6 is inserted into the other hole 4 a and the tip thereof is brought into contact with the reinforcing bar 2. When the welding rod 5 is connected to the plus side of 7 and the steel rod 6 is connected to the minus side to perform arc welding, the steel rod 6 is on the ground side and the tip of the welding rod 5 is Weld to 2. Therefore, as shown in FIG. 7, an anode cable 8 is connected to the welding rod 5 to form an anode. When a direct current is applied to the anode, the reinforcing strength of the reinforcing bar 2 with respect to the concrete 1 is reduced by electrolysis, and furthermore, the expansion of corrosion products generated by electrolytic corrosion and cracking of the concrete 1 due to the generated oxygen gas pressure occur. .

Next, the installation of the cathode according to the present invention will be described. As shown in FIG. 2, the disassembled region R shown in FIG. 1 is divided into small blocks 9, 9,... And disassembled for each block 9, 9,. I do. Although FIG. 2 shows one divided into four blocks, the shape and number of the small blocks 9, 9... Are arbitrarily determined.

In FIG. 2, in order to form a cross-shaped concrete deteriorated portion 10 inside the cut 3 in the demolition area R, a concrete surface corresponding to the concrete deteriorated portion 10 is formed on the concrete surface shown in FIG. As shown in FIG. 9, the vinyl chloride containers 11 are respectively mounted. The mounting surface and the upper surface of the vinyl chloride container 11 with respect to the concrete 1 are open, and the open side wall 11a of the vinyl chloride container 11 is opened.
Is attached to the concrete 1 using an adhesive or the like. In addition to using a soft epoxy-based elastic adhesive, the mounting method can be replaced with a waterproof material instead of the adhesive and fixed with an anchor, and the mounting method is not specified. Absent.

Thus, the wire mesh having the length and width extending over substantially the entire inner surface of the vinyl chloride container 11 is provided in the vinyl chloride container 11 mounted on the surface of the concrete 1 at the small blocks 9, 9... 12 is inserted. The wire mesh 12
May be inserted into the vinyl chloride container 11 before the vinyl chloride container 11 is mounted on the small blocks 9, 9,..., And then the vinyl chloride container 11 may be mounted on the surface of the concrete 1. A cathode cable 13 is connected to the metal net 12 to form a cathode. Further, the vinyl chloride container 11 is filled with a magnesium chloride solution 14 as an oxidation accelerator to form a cathode surface electrode 15. The width of the vinyl chloride container 11 is about 10 cm, the thickness is about 1 cm, and the vertical length is appropriately set in accordance with the length of each small block 9 in the longitudinal direction. Be changed. Thus, since the magnesium chloride solution 14 is in direct contact with the surface of the concrete 1, the interface resistance is extremely small, and the magnesium chloride solution 14 is sufficiently stored in the vinyl chloride container 11. , It is possible to prevent an increase in resistance due to drying,
After cracking of the concrete, the magnesium chloride solution 14 penetrates into the cracked portion, and the magnesium chloride solution 14 comes into contact with the nearest reinforcing bar 2, so that the progress of corrosion of the reinforcing bar 2 is remarkably promoted.

FIGS. 10 to 1 show the cathode electrode.
As shown in FIG. 2, the outer bar electrode 16 of the surface electrode 15 can be used. As shown in FIG. 10, the rod electrode 16 first has a plurality of holes 17, 17... Formed on both sides near the reinforcing bar 2 interposed in the concrete deteriorated portion 10 in the small block 9. The holes 17, 17... Can be provided at positions about 5 cm away from the reinforcing bar 2. The steel pipes 18, 1 in which a number of small holes 18a, 18a.
8 is inserted. Further, at the mouths of the holes 17, 17,..., A magnesium chloride solution 14 as an oxidation promoter filled in the steel pipe 18 with a water-stopping material 19 of silicone resin interposed.
a is configured not to leak out of the concrete 1. Further, a transparent vinyl chloride pipe 20 having an open upper surface is connected to the rear end of the steel pipe 18, and is formed in a T-shape by the steel pipe 18 and the vinyl chloride pipe 20. The cathode rod 13 is formed by connecting the cathode cable 13a.

The transparent vinyl chloride tube 20 is shown in FIG.
In 2, a T-shaped connection pipe 21 is connected to the rear end of the steel pipe 18, and an upper open / closed upper vinyl chloride pipe 20 a is connected to an upper opening of the T-shaped connection pipe 21. Although the lower PVC pipe 20b having only the upper surface opened is connected to the lower opening of the T-shaped connecting pipe 21, the connection method of the transparent PVC pipe 20 should not be limited to this.

Since the water content on the cathode side is reduced by electrolysis during energization, the resistance may be increased by drying. Therefore, in order to prevent this increase in resistance, several tens of cc of excess liquid is stored in advance in the transparent vinyl chloride pipe 20 connected to the rear end of the steel pipe, and sufficient water is supplied to the cathode side. , And is configured to prevent the increase in resistance. When the energization time is long, a large-capacity transparent vinyl chloride tube 20 may be used. Alternatively, a vinyl tube, a poly container or the like can be used.

Thus, the magnesium chloride solution 1
4a has a function of reducing the concrete resistance, promoting the corrosion of the reinforcing bar 2 by chlorine ions and the deterioration of concrete by magnesium ions. When the concrete strength is decreased by the ions, insoluble calcium carbonate may precipitate at the same time and precipitate in the steel pipe 18 to increase the resistance. In this case, the calcium carbonate may lose its weight due to its own weight. The sedimentation occurs at the lower end of the transparent vinyl chloride tube 20, so that the increase in the resistance can be prevented.

In addition, the energization is performed by a DC voltage low current power supply. Further, the required amount of current is 50 V
Within 1 to 5 per area subject to deterioration of concrete 1
About 7 days to about 10 days are allowed for about A, but the present invention is not limited thereto. That is, the longer the energization days, the better.

By this energization, as shown in FIG. 2, in the disassembly area R, a substantially deteriorated concrete-shaped portion 10 is formed. That is, the concrete deteriorated portion 10 has a reduced concrete strength, cracks due to reinforcing steel corrosion and the reinforcing steel 2
Is a site where the adhesive strength of the concrete 1 to the concrete 1 also decreases. Therefore, as shown in FIG. 3, holes are drilled in places of the cross-shaped concrete deteriorated portion 10, and a static crushing agent such as calcium oxide is inserted into the holes, and the static crushing agent acts by the action of the static crushing agent. The U-shaped concrete deterioration part 10 is crushed. Alternatively, it is also possible to insert a lock jack into the hole and drive the lock jack to crush the cross-shaped concrete deteriorated portion 10. Thus, each small block 9,
9 ...
Are exposed, and the small blocks 9, 9,... Can be easily removed by cutting the exposed rebars 2, 2,. Thus, as shown in FIG. 4, the dismantling region R of the concrete 1 is efficiently dismantled and removed.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0020]

According to the present invention, as described in detail in the above embodiment, the concrete demolition area is divided into small blocks.
Then, by attaching a cathode composed of a surface electrode or a rod electrode to each peripheral portion of each small block and applying a DC current thereto, a deteriorated concrete portion is formed in each peripheral portion of each small block. Thus, the concrete demolition area is extremely easily and quickly dismantled by crushing the deteriorated portion of the concrete using a static crushing agent or the like to expose the reinforcing bar, cutting the reinforcing bar and dismantling and removing each small block. It can be done. In addition, the preparation work is a relatively small work since only the installation of the electrodes and the cables is performed. The power supply equipment needs to be extremely small, and the amount of power supply is small and there is no danger of electric leakage. Furthermore, maintenance during power supply is not required, and noise, vibration,
There is almost no environmental impediment such as dust, and the energized area is only the peripheral part of the small block as described above, and sufficient water is constantly supplied to the cathode side. The interface resistance becomes smaller, and the current-carrying efficiency is improved. Therefore, the deterioration of the concrete proceeds extremely efficiently, and further, the cathode can be used repeatedly, which is combined with the fact that the facilities and work are light. It contributes to cost reduction, and the current-carrying area is limited by the cathode,
This is an invention that has a truly significant effect, such as no longer having any adverse effect on areas other than the disassembly area.

[Brief description of the drawings]

FIG. 1 is a front view showing a dismantling area of reinforced concrete.

FIG. 2 is a front view showing the degraded concrete portion by dividing the disassembly area of FIG. 1 into small blocks.

FIG. 3 is a front view showing a state in which the deteriorated concrete portion in FIG. 2 is crushed using a static crushing agent.

FIG. 4 (a) is a front view showing a state where each small block in FIG. 3 is removed and a concrete dismantling area is dismantled. (B) Cross-sectional view of the above (a).

FIG. 5 (a) is a front view of forming a hole in a reinforcing bar embedded in reinforced concrete to form an anode. (B) Cross-sectional view of the above (a).

FIG. 6 is an explanatory view showing a state in which a welding rod and a steel rod are inserted into the holes of FIG. 5 and the welding rod is welded to a reinforcing bar;

FIG. 7 is an explanatory longitudinal sectional view showing a state in which a welding rod is welded to a reinforcing bar to form an anode according to FIG. 5;

FIG. 8 is a front view showing a state of forming a cathode using surface electrodes.

FIG. 9 is a vertical side view of FIG. 8;

FIG. 10 is a front view showing a state in which a hole is drilled in the vicinity of a reinforcing bar for forming a cathode using a bar electrode.

FIG. 11 is a vertical sectional side view showing a state where a bar electrode is inserted into the hole of FIG. 10;

FIG. 12 is an enlarged longitudinal side view illustrating the rod electrode of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete 2 Reinforcing bar 4 Hole 5 Welding rod 9 Small block 10 Concrete deterioration part 11 Vinyl chloride container 12 Wire mesh 14, 14a Magnesium chloride solution 15 Surface electrode 16 Bar electrode 17 Hole 18 Steel pipe 20 Vinyl chloride pipe R Dismantling area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukinori Kiuchi 417-16 Nakaarai, Ageo City, Saitama Prefecture Inside Nakabo Tech R & D Co., Ltd. (72) Tatsuya Ishii 417-16 Nakaarai, Ageo City, Saitama Prefecture Na Corporation Cabotech R & D Laboratory

Claims (3)

[Claims] 1. A method of disassembling a reinforced concrete structure after a direct current is applied by connecting a cathode to a concrete surface and using a reinforcing bar as an anode, and disassembling the reinforced concrete structure into arbitrary small blocks in advance. At the periphery of the small block, one side open portion of a container formed of an electrical insulator is mounted facing the small block side, and further, a wire mesh is inserted into the container and an oxidation promoter is filled. Dismantling of a reinforced concrete structure characterized in that concrete can be removed and carried out for each of the small blocks by forming a cathode and applying the DC current to degrade the concrete at the cathode mounting site. Method. 2. A method of disassembling a reinforced concrete structure after a direct current is applied by connecting a cathode to a concrete surface and using a reinforcing bar as an anode, and disassembling the reinforced concrete structure into arbitrary small blocks in advance. A plurality of holes are drilled from the concrete surface in the vicinity of the reinforcing bar in the small block, and a steel tube having a large number of small holes is inserted into each of the holes, and the steel tube is filled with an oxidation promoter to form a cathode. A method of dismantling a reinforced concrete structure, characterized in that the DC current is applied to deteriorate the concrete at the cathode mounting site so that concrete can be removed and carried out for each of the small blocks. 3. The method for dismantling a reinforced concrete structure according to claim 2, wherein the steel pipe is formed in a T-shape by connecting a transparent pipe to a rear end thereof.