JP3000411B2 - Early diagnosis method and repair method for cracks in reinforced concrete structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rather <br/>如shore wall or pier pillar relates early diagnosis method and method of repairing a crack portion of reinforced concrete structures with an immersion face in seawater .

[0002]

2. Description of the Related Art Reinforced concrete structures used in the state of being immersed in seawater are porous because they are porous, easily absorb water, and easily penetrate water. The rebar may be significantly corroded, and when the rebar is corroded, the rebar is enlarged and a crack is generated in the concrete layer, so that the strength of the rebar itself is reduced and the strength of the reinforced concrete structure is also reduced.

[0003] Therefore, in a reinforced concrete structure having a surface immersed in seawater, it is necessary to periodically inspect the state of crack generation in the concrete layer, that is, to diagnose a so-called reinforced concrete structure. In the inspection of the crack, a diagnosis of the occurrence of the crack is conventionally performed by a diver's naked eye.

[0004]

However, there is a problem in the conventional method of visually diagnosing a reinforced concrete structure as described above. In other words, shellfish and algae often adhere to the seawater immersion surface of this type of reinforced concrete structure,
Not only was the crack found troublesome, but also fine cracks were difficult to find, and thus accurate diagnosis could not be made.

[0005]

Means for Solving the Problems The present invention has been made to solve the above-mentioned conventional problems, and is arranged so as to face a seawater immersion surface of a reinforced concrete structure .
The electrode in sea water as an anode, the current density rebar that is furnished between as the cathode two electrodes in reinforced concrete structures 4
00mA / ft ² or more a direct current flows so that, cracking portion of the iron <br/> muscle concrete structure of the cracked portion reinforced concrete structure which is adapted to deposit a <br/> electrodeposit rich magnesium substance in It provides an early diagnosis method.

[0006]

[Work] Anode electrode in seawater and reinforced concrete structure
The current density is 4 between the reinforcing bars inside the structure.
00mA / ft ² When a DC current is passed as described above,
Since cracks easily flow current, reinforced concrete structures
Of milky white electrodeposit rich in magnesium in cracks
To fold out. Therefore, the presence or absence of cracks on the seawater immersion surface
And deposit the electrodeposits necessary to know the extent
It is possible to greatly shorten the power supply period for the operation.

Another aspect of the present invention is a reinforced concrete.
Electricity in seawater placed opposite the seawater immersion surface
The pole is used as the anode, and the interior is installed in the reinforced concrete structure.
The current density between the two electrodes is 400 mA /
ft ² a direct current flows so that above, reinforced concrete
Folded magnesium-rich electrodeposits at cracks in sheet structure
After checking the presence and extent of cracks,
Reduce the strength to 40 to 400 mA / ft ² and
A protective coating made of electrodeposit is formed on the seawater immersion surface of the
Cracks in reinforced concrete structures
It provides a repair method for the place.

[Work] Anode electrode in seawater and reinforced concrete structure
The current density is 4 between the reinforcing bars inside the structure.
00mA / ft ² When a DC current is passed as described above,
Early milky white electrodeposits rich in magnesium in cracks
Power supply period can be greatly reduced.
After checking the presence and degree of cracks,
Flow density of 40-400 mA / ft ² Reinforced concrete
Electrodeposited protective coating on seawater immersed surface of cleat structure
Cracks in reinforced concrete structures by forming
It is possible to reliably and firmly repair cracks
is there.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for diagnosing a reinforced concrete structure according to the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a concrete structure in which a reinforcing bar 2 is provided.
Has a seawater immersion surface 3 that is in contact with the surface. An electrode 4 is disposed in the sea facing the seawater immersion surface 3 of the concrete structure 1, and the electrode 4 is used as an anode, and the reinforcing bar 2 is used as a cathode and connected to a DC power supply 7 by wirings 5 and 6. .

When a DC current having a large current density is caused to flow by the DC power supply 7, an electrodeposit is deposited in the crack 8 of the concrete structure 1 as shown in FIG. More specifically, when a direct current is applied between the electrode 4 and the reinforcing bar 2, alkaline earth metal ions such as calcium ions and magnesium ions dissolved in seawater are immersed in the voids in the concrete layer and the concrete layer as electrodeposits. Precipitates on the surface.

Since the cracks 8 in the reinforced concrete structure 1 are caused by enlargement due to corrosion of the reinforcing bars 2, a large amount of DC current flows through the cracks 8. As a result, the electrodeposits 9 are deposited on the cracks 8. Is preceded. The chemical composition of the electrodeposit 9 changes depending on the relationship with the current density. FIG. 3 shows the relationship between the current density and the amount of electrodeposits deposited. When the current density is a small value of 40 mA / ft ² or less, the amount of calcium increases and the amount of magnesium decreases. Has been confirmed. The electrodeposit is crystalline and porous.

On the contrary, when the current density is increased to 400 mA / ft ² or more, the amount of calcium decreases and the amount of magnesium increases. The electrodeposits in this case are milky white, amorphous and easily disintegrating, but they are milky white and have a conspicuous color even in the sea, making them suitable for finding defects in concrete. As described above, the properties of the electrodeposit vary depending on the current density at the time of energization, and the amount of deposition is greatly related to this. That is, as shown in FIG. 4, when the current density is increased, the deposition amount of the electrodeposit increases.

As described above, the properties and deposition amount of the electrodeposits change depending on the current density. Therefore, in the present invention, focusing on these properties, the current density is higher than the current density used in the normal seawater electrodeposition process. By passing a direct current having a high density, an electrodeposit is deposited at the cracked portion 8 at an early stage, and the deposited state can be visually identified to diagnose the presence or absence of the cracked portion and its degree.

[0013] Of course, after diagnosing a reinforced concrete structure by such a method, if a crack 8 is found and its repair becomes necessary, the current density is reduced to about 40 to 400 mA / ft ² and a DC current is applied. As a result, a protective film made of a good electrodeposit can be formed in the concrete layer and on the surface thereof.

[0014]

According to the present invention , an anode electrode in seawater,
Reinforcing bar as a cathode inside a reinforced concrete structure
So that the current density becomes 400 mA / ft ² or more during
When a DC current is applied, the cracks easily flow through the
Magnesium-rich milk at cracks in concrete structures
White electrodeposits fall out early. For this reason, the seawater immersion surface
Required to know the presence and extent of cracks in
Significantly shorten the power-on period to allow the kimono to be extended
Is now possible.

Further , as in the present invention, the anode electrode in seawater is used.
As poles and cathodes inside reinforced concrete structures
Current density is 400 mA / ft ² or more between the rebar
When a DC current is applied, the cracks become magnesium
To enrich the milky white electrodeposits quickly,
In addition to being able to greatly shorten, there is no crack
And after diagnosing the degree, the current density is increased to 40 to 400 mA /
ft ² and immersed in seawater of reinforced concrete structure
By forming a protective coating made of electrodeposits on iron,
Cracks in reinforced concrete structures reliably and
It has become possible to make strong repairs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a state of a method for diagnosing a reinforced concrete structure according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a crack generated in a reinforced concrete structure.

FIG. 3 is an explanatory diagram of a current density and a chemical composition of an electrodeposit when electrodeposition is performed on a reinforced concrete structure.

FIG. 4 is an explanatory diagram of a current density and a deposition amount of electrodeposits when electrodeposition is performed on a reinforced concrete structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete structure 2 Reinforcement 3 Seawater immersion surface 4 Electrode 5, 6 Wiring 7 DC power supply 8 Crack part 9 Electrodeposit.

────────────────────────────────────────────────── ─── Continued on the front page (72) Tsutomu Fukute, Inventor 3-1-1 Nagase, Yokosuka City, Kanagawa Prefecture Inside the Port and Harbor Research Institute, Ministry of Transport (72) Inventor Masami Abe 3-1-1 Nagase, Yokosuka City, Kanagawa Prefecture Within the Port and Harbor Research Institute of the Ministry of Transport (72) Inventor Yu Yokota 2109-8 Yashima Nishimachi, Takamatsu City, Kagawa Prefecture Inside Shikoku Research Institute (72) Inventor Harutoshi Sasaki 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Co., Ltd. (56) References Mitsui Engineering & Shipbuilding Technical Report, [143] (issued June 1, 1991) Kumada, Miyazaki, Sasaki, five others, p. 1-7 “Corrosion prevention and repair technology for reinforced concrete structures using electrodeposition” (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 17/00 G01N 27/26

Claims (2)

(57) [Claims] Claims: 1. On a seawater-immersed surface of a reinforced concrete structure
The electrodes in seawater arranged so as to face an anode, both the reinforcing bars is furnished to the reinforced concrete structure as a cathode
The current density between the electrodes should be 400 mA / ft ² or more
DC current is flowed, early diagnosis method for cracking portion of reinforced concrete structures, characterized in that so as to precipitate the iron muscle concrete structure of electrodeposits rich magnesium quality crack portion. 2. On the surface immersed in seawater of a reinforced concrete structure.
An electrode in seawater arranged to face is used as an anode, and the iron
Reinforcing bars inside a reinforced concrete structure are used as cathodes.
400 mA / ft current density between electrodes ² To be more than
DC current through the cracks in reinforced concrete structures
Precipitated magnesium-rich electrodeposits with cracks
After diagnosing nothing and its extent, the current density is 40 to 400 mA
/ Ft ² Immersed in seawater of reinforced concrete structures
That a protective coating consisting of electrodeposits is formed on the surface
Cracks in reinforced concrete structures characterized by
Repair method.