JP7060924B2 - Washing-less repair method - Google Patents

Description

The present invention relates to a method for repairing a steel structure.

When repairing and painting steel structures, it is recommended to apply the Rc-I coating system (Non-Patent Document 1), which has excellent long-term durability in repainting of painted bridges. In this substrate adjustment treatment, it is necessary to treat the rust removal degree specified in ISO8501-1 to be Sa2 1/2 and to reduce the amount of adhering salt to 50 mg / m ² or less. As a conventional method related to this, for example, Non-Patent Documents 1 and 2 can be mentioned.

In order to achieve an attached salt content of 50 mg / m ² or less, washing with water is usually required. However, from the viewpoint of the impact on the surrounding residents and environmental conservation, the manager cannot obtain permission for drainage locally for bridges that cross urban areas or some rivers, and all wastewater must be collected. Is so difficult that it is difficult to apply water washing in areas where local drainage permits are not available.

To solve such a problem, a method of applying an alkaline aqueous sodium carbonate solution after adjusting the substrate with a rotary grinding tool or the like has been proposed (see, for example, Patent Documents 1 and 2). Sodium carbonate has an action of removing salt from the corrosive interface by reacting chloride ions contained in rust generated on the surface of a steel structure with carbonic acid ions. Patent Documents 1 and 2 describe that the washing step can be omitted by applying an aqueous sodium carbonate solution after adjusting the substrate to detoxify the action of chloride ions, which are corrosive substances.

Japanese Unexamined Patent Publication No. 2007-283237 International Publication WO2007-123149

Steel Road Bridge Anticorrosion Handbook, Nippon Road Association, pp.III-62-III-63, 2014 Atsumi Imai, 2 others, A Study on Implementation of Anticorrosion Repair Painting Method for Weathering Steel Bridges, JSCE Proceedings A1 (Structural and Seismic Engineering), Vol. 68, No2, 347-355, 2012

The sodium carbonate aqueous solution used in the methods of Patent Documents 1 and 2 has an excellent effect of suppressing the action of chloride ions, and is effective when repairs are frequently performed. However, as a result of the studies by the present inventors, it has been found that it is necessary to use a corrosion inhibitor that can reduce the frequency of repairs when long-term durability of the repair coating is desired without washing with water. .. In view of the above, the inventor of the present application has diligently studied and found a method for repairing a steel structure having long-term durability without washing with water, and completed the present invention.

An object of the present invention is to provide a method for repairing a steel structure having long-term durability without washing with water.

The present inventor has studied diligently, found a method for solving the above problems, and completed the present invention.
The present invention is the following (1) to (6).
(1) A repair painting method for steel structures.
The surface A of the corroded steel structure is treated so that the exposed area ratio of the base material is 30% or more, and the base material adjustment step of obtaining the base material adjusted surface B is performed.
A corrosion suppression step of applying a corrosion inhibitor containing hydrotalcite and / or hydrotalcite to the surface B to obtain a surface C coated with the corrosion inhibitor.
A water-washing-less repair method.
(2) The water-washless repair method according to (1) above, comprising a polishing and grinding step of grinding or polishing the surface C to obtain the ground or polished surface D.
(3) The water-washing-less repair method according to (2) above, wherein the polishing and grinding process is performed by a blast treatment.
(4) A paint coating step of applying a zinc powder-containing paint to the surface C to obtain a surface E coated with the zinc powder-containing paint.
The painting process of applying paint to the surface E and
The water-washing-less repair method according to (1) above.
(5) A paint application step of applying a zinc powder-containing paint to the surface D to obtain a surface F to which the zinc powder-containing paint is applied.
The painting process of applying paint to the surface F and
The water-washless repair method according to (2) or (3) above.
(6) The metal rotating disk has a mounting portion at the center for attaching the substrate adjusting step to the rotating shaft of the rotary drive device, and a metal rotating disk having a grinding surface composed of a grinding machine surface and a grinding peripheral surface. The above (1) to (5) are carried out using a rotary grinding tool in which hard particles having a Morse hardness of more than 9 are waxed on a part or all of the ground surface so as to have a surface density of 20 pieces / cm ² or more. The water-washing-less repair method described in any of the above.

According to the present invention, it is possible to provide a repair method (water wash-less repair method) for a steel structure having long-term durability without washing with water. For example, when a weathering steel structure is to be repaired, it is possible to provide a repair method having long-term durability equivalent to or close to that of the Rc-I coating system for weathering steel without washing with water.

FIG. 1 is a diagram showing a process flow of level 1 in the embodiment. FIG. 2 is a diagram showing a process flow of level 2 in the embodiment. FIG. 3 is a photograph showing the status of (a) shielding exposure test and (b) salt water spraying test in Examples. FIG. 4 is a graph showing the swelling evaluation result in Example 2. FIG. 5 is a graph showing the rust evaluation result in Example 3. FIG. 6 is a graph showing the rust evaluation results in Example 4. FIG. 7 is a graph showing the swelling evaluation result in Example 5. FIG. 8 is a graph showing the swelling evaluation result in Example 6. FIG. 9 is a diagram showing a process flow at level 2'.

The present invention will be described.
The present invention is a repair coating method for a steel structure, wherein the surface A of a corroded steel structure is treated so that the exposed area ratio of the base material is 30% or more, and the base material adjustment to obtain the base material adjusted surface B is obtained. A washing-less repair comprising a step and a corrosion suppressing step of applying a corrosion inhibitor containing hydrocarbylite and / or hydrotalcite to the surface B to obtain a surface C coated with the corrosion inhibitor. It is a construction method.
Such a water-washing-less repair method is also referred to as "the method of the present invention" below.

<Base material adjustment process>
The method of the present invention comprises a substrate adjusting step.
The substrate adjusting step provided in the method of the present invention is a step of performing a treatment on the surface A of the corroded steel structure so that the exposed area ratio of the substrate is 30% or more to obtain the surface B to which the substrate has been adjusted.

The steel structure is not particularly limited as long as it is a structure that uses steel as a main material and functions as a social or corporate infrastructure. For example, steel bridges, steel buildings, steel plants, steel cargo handling machines can be mentioned, and the method of the present invention can be preferably applied to steel structures made of weathering steel, particularly bridges made of weathering steel. ..
Corrosion progresses with the passage of time, so repair coating is required on the corroded part to prevent it.

In the substrate adjusting step, the surface A of the corroded steel structure as described above is treated so that the exposed area ratio of the substrate is 30% or more. Specifically, the processing can be performed by using a conventional substrate adjustment method, for example, a blasting process, or a tool such as a grinder or a disc grinder in which a rotary grindstone, a grinding disk, or the like is attached to an electric rotary drive device. ..
Further, it has a metal rotating disk having a mounting portion at the center for attaching the substrate adjusting process to the rotating shaft of the rotary drive device and a grinding surface composed of a grinding machine surface and a grinding peripheral surface, and has a grinding surface of the metal rotating disk. A rotary grinding tool (hereinafter also referred to as "diamond tool") in which hard particles having a Morse hardness of more than 9 are waxed so as to have a surface density of 20 pieces / cm ² or more can be used for a part or all of the grinding tools. preferable. The reason is that by using this rotary grinding tool, it is possible to efficiently remove the corrosion products of the steel structure and shorten the time required for the substrate adjusting process.
Examples of the process using such a rotary grinding tool include the methods described in Japanese Patent No. 5506141 or Japanese Patent No. 5686338 already proposed by the applicants of the present application.

By such treatment, the surface A is ground or polished so that the base material exposed area ratio (base material exposed area of the treatment target surface / area of the treatment target surface) is 30% or more (preferably 50% or more).
The surface of the steel structure obtained by such a treatment and having an exposed base material ratio of 30% or more is the surface B.

<Corrosion suppression process>
The method of the present invention comprises a corrosion suppression step.
The corrosion suppressing step provided in the method of the present invention is a step of applying a corrosion suppressing agent containing hydrocarbylite and / or hydrotalcite to the surface B to obtain a surface C to which the corrosion suppressing agent is applied. ..

As a result of the studies by the present inventors, it was found that the application of a corrosion inhibitor containing hydrocarbimite and / or hydrotalcite improves the durability in the long term as compared with the application of an aqueous sodium carbonate solution. .. The cause of this is not always clear, but hydrotalcite and / or hydrotalcite is powdery, less soluble in water than sodium carbonate, and can stably fix chloride ions even if it remains in the repaired area. It is thought that this is because of it. In addition, since sodium carbonate becomes alkaline when dissolved in water, there is a concern that it may have an adverse effect on painting, but hydrotalcite and hydrotalcite, which are difficult to dissolve in water, do not cause such a problem. As described above, according to the method of the present invention including the corrosion suppressing step of applying the corrosion suppressing agent containing hydrocarbamite and / or hydrotalcite to the surface after the substrate preparation, the washing with water required in the conventional method is unnecessary. The inventor of the present application has found that long-term durability can be imparted to a steel structure.

The corrosion inhibitor contains hydrotalcite and / or hydrotalcite, and is preferably a solution in which hydrotalcite and / or hydrotalcite is dissolved or a dispersed dispersion. Hydrotalcite and / or hydrotalcite is usually powdery and sparingly soluble in water. Therefore, the corrosion inhibitor is preferably a dispersion liquid in which powdered hydrocalmite and / or hydrotalcite is dispersed in water (dispersion medium). The corrosion inhibitor may be hydrotalcite and / or hydrotalcite itself. For example, if the surface B is sufficiently wet, hydrotalcite and / or hydrotalcite itself may be applied.

The content of hydrotalcite and / or hydrotalcite in the corrosion inhibitor is preferably 1 to 25% by mass, more preferably 5 to 15% by mass, and even more preferably about 10% by mass. ..

The method for applying the corrosion inhibitor containing hydrotalcite and / or hydrotalcite to the surface B is not particularly limited, and for example, it can be applied using a brush or a roller.

The surface of the steel structure coated with the corrosion inhibitor obtained by such treatment is the surface C.

<Polishing and grinding process>
The method of the present invention can include a polishing and grinding step.
The polishing and grinding step included in the method of the present invention is a step of grinding or polishing the surface C to obtain a grounded or polished surface D.

In the polishing and grinding step, the surface C as described above is ground or polished. Of course, the mode may be such that the grinding process and the polishing process are performed together. Specifically, the processing can be performed by using a conventionally known method, for example, a tool such as a grinder or a disc grinder in which a rotary grindstone, a grinding disk, or the like is attached to an electric rotary drive device.

The polishing and grinding process is preferably performed by a blasting process. Further, it is preferable to perform the treatment by the shot blast method so that the rust removal degree specified in ISO8501-1 is Sa2 1/2. The reason is that by using the blast treatment, the corrosion inhibitor remaining on the surface can be reliably removed, and an anchor pattern necessary for improving the adhesion of the coating film can be formed.

The surface D, which has been ground or polished, is the surface D obtained by such treatment.

<Paint application process>
The method of the present invention can include a paint coating step.
The paint coating step provided in the method of the present invention is a step of applying a zinc powder-containing paint to the surface C to obtain a surface E coated with the zinc powder-containing paint, or a step of applying a zinc powder-containing paint to the surface D. This is a step of applying the zinc powder-containing paint to obtain a surface F coated with the zinc powder-containing paint.

In the paint application step, for example, a conventionally used organic or inorganic zinc rich primer can be used as the zinc powder-containing paint, and this can be applied to the surface C or the surface D.

The zinc powder-containing coating composition contains 100 parts by mass (solid content weight) of the binder resin, 200 to 800 parts by mass of the zinc powder, 1 to 95 parts by mass of the corrosive ion immobilizing agent component, and 200 to 200 parts of a solvent for dispersing them. A coating composition containing 1000 parts by mass is preferable.
Further, the binder resin is more preferably an inorganic resin or an organic epoxy resin, an acrylic resin, or a urethane resin.
Further, it is more preferable that the corrosive ion immobilizing agent component is hydrotalcite and / or hydrotalcite.
Further, it is preferable that it further contains a coupling agent.

It contains 100 parts by mass (solid content weight) of the binder resin, 200 to 800 parts by mass of zinc powder, 1 to 95 parts by mass of the corrosive ion immobilizing agent component, and 200 to 1000 parts by mass of a solvent for dispersing them. The binder resin is an inorganic resin or an organic epoxy resin, an acrylic resin, or a urethane resin, and the corrosive ion-fixing agent component is hydrocarbimite and / or hydrotalcite, and zinc containing a coupling agent. The powder-containing paint composition is also referred to as "special organic zinc rich paint" below.

The method of applying the zinc powder-containing paint to the surface C or the surface D is not particularly limited, and the paint can be applied by using, for example, a spray, a brush, or a roller.

The thickness of the film formed by applying the zinc powder-containing paint to the surface C or the surface D is not particularly limited, but is preferably 10 to 300 μm, more preferably 25 to 125 μm, and more preferably about 75 μm. Is even more preferable.

The surface E coated with the zinc powder-containing paint obtained by subjecting the surface C to the above-mentioned treatment is the surface E. Further, the surface F coated with the zinc powder-containing paint obtained by subjecting the surface D to the above-mentioned treatment is the surface F.

<Painting process>
The method of the present invention preferably comprises a painting step.
The coating step included in the method of the present invention is a step of applying coating to the surface E or the surface F.

This coating is for blocking the influence of the environment on the steel structure, and also for preventing deterioration of the coating film layer applied to the steel material surface due to ultraviolet rays or the like. Various paints such as polyurethane resin paints and epoxy resin paints can be used depending on the requirements of the surrounding environment. These paints may be applied a plurality of times to form a coating film having two or more layers.
Further, one or more layers of the fluororesin paint may be further applied.

The method of applying the coating to the surface E or the surface F is not particularly limited, and examples thereof include a method of applying the coating using a spray, a brush, or a roller.

The thickness of the film formed by applying the paint to the surface E or the surface F is not particularly limited. For example, when two or more layers of a paint such as a polyurethane resin paint or an epoxy resin paint are formed, the total layer thickness thereof is preferably 10 to 400 μm, more preferably 50 to 200 μm, and about 100 μm. It is more preferable to have.
Further, for example, when one or more layers of the fluororesin paint are applied, the total layer thickness is preferably 10 to 200 μm, more preferably 30 to 100 μm, and further preferably about 50 μm.
As the paint, a weak solvent type modified epoxy resin paint, a weak solvent type polyurethane resin paint, or a weak solvent type fluororesin paint may be used.

Examples of the present invention will be described. The present invention is not limited to the following examples.

<Test material>
SMA490W weathering steel (I cross-section girder: 500 mm x 200 mm x 9 mm x 9 mm, length 1,000 mm) was sprayed with a 3 wt% -NaCl aqueous solution 5 times a week for 18 months to artificially rust. Was generated.

First, the steel surface was exposed by about 50% with a diamond tool, and the amount of adhering salt was measured. Next, a corrosion inhibitor was applied by a brush, a blast treatment was performed, the degree of substrate adjustment was set to ISO Sa2 1/2, and then the amount of adhering salt was measured again. For comparison, blasting was performed without applying a corrosion inhibitor and the amount of adhering salt was measured. The ratio of the amount of adhering salt after the blasting to the amount of adhering salt before the blasting was determined as a percentage (residual adhering salt content). As a result, the residual salt content was 25.1% when the corrosion inhibitor was not applied, whereas the residual salt content was 12.8% when the corrosion inhibitor was applied.

<Test material>
SMA490W weathering steel (150 mm × 70 mm, thickness: 6 mm) was sprayed with a 3 wt% -NaCl aqueous solution 5 times a week for 8 months to artificially generate rust.

<Test level>
First, a comparison was made between a repair method (level 1) in which the amount of adhering salt was reduced to 50 mg / m ² or less by washing with water and blasting, and a water-washing-less method (level 2) of the present invention. Level 1 is an ideal method from the viewpoint of corrosion resistance, although the cost is high. The contents are also shown in Table 1.

[Level 1] Repair method by washing with water and blasting First, expose about 50% of the steel surface with a hammer keren and a diamond tool. Next, blasting and washing with water are repeated to reduce the degree of substrate adjustment to ISO Sa2 1/2 and the amount of adhering salt to 50 mg / m ² or less. Then, within 4 hours, the first layer treatment in the painting described later is performed.

[Level 2] Wash-less construction method First, expose the steel surface by about 50% with a hammer keren and a diamond tool. Next, the corrosion inhibitor is applied by brush. Apply once / day and twice. Then, a blast process is performed, and the degree of substrate adjustment is set to ISO Sa2 1/2. Then, within 4 hours, the first layer treatment in the painting described later is performed.

Then, the following treatments were performed at each of Levels 1 and 2.

After applying a special organic zinc rich paint to form a film having a film thickness of 75 μm, a moisture-curable polyurethane resin paint (trade name: V-Gran undercoat, manufactured by Dai Nippon Toryo Co., Ltd.) was applied twice. Since a film having a film thickness of 50 μm was formed by one application, the film thickness of the film made of the moisture-curable polyurethane resin paint is 100 μm. Then, a thick film type fluororesin paint (trade name: V-Freon HB, manufactured by Dai Nippon Toryo Co., Ltd.) was further applied to form a film of 50 μm. A composite film was formed by such an operation.

The process flows at Level 1 and Level 2 as described above are summarized in FIGS. 1 and 2.

<Test method>
The test methods are "shielded exposure test" at the exposure test site in Okinawa Prefecture (area corresponding to C4 of ISO9223-92 corrosive classification) and 0.2 wt% -NaCl aqueous solution 5 times a week in a closed box. A "salt water spraying test" for spray spraying was carried out for one year. In both the shield exposure test and the salt water spray test, the test pieces were installed with the angle horizontal and the evaluation surface facing up. An example of the shield exposure test situation is shown in FIG. 3 (a), and an example of the salt water spray test situation is shown in FIG. 3 (b).

<Evaluation method>
The appearance of the test piece after exposure was evaluated for swelling according to ASTM standard D714-02. Evaluation 10 indicates that no swelling has occurred, and indicates that the swelling that has occurred in the order of 8, 6, 4, and 2 has progressed.

<Result>
FIG. 4 shows the swelling evaluation results according to ASTM standard D714-02.

Comparing the [Level 1] water-washing and blasting repair method with the [Level 2] water-washing-less method, the following results were obtained.
-In the shielded exposure test, no swelling was observed at evaluation 10 at [Level 1], and swelling at evaluation 8 was observed at [Level 2].
-In the 0.2% salt water spray test, both [Level 1] and [Level 2] were evaluated as 10 for the composite membrane, and there was no difference in evaluation between the two levels.

In this way, it is considered that the [Level 2] water-washing-less method has the same or similar durability as the ideal repair method [Level 1] water-washing and blasting repair method. Will be.

<Test method>
The test material used in Example 2 was subjected to the same level 1 and level 2 treatments as in Example 2 to obtain test pieces. Then, a test was conducted on this test piece.
As a test method, a "salt water spraying test" was carried out for 16 months in which a 0.2 wt% -NaCl aqueous solution was sprayed 5 times a week in a closed box. All the test pieces for the salt water spray test were installed with the angle horizontal and the evaluation surface facing up. The salt water spraying test situation is the same as in FIG. 3 (b).

<Evaluation method>
The appearance of the test piece after exposure was evaluated for rust according to ASTM standard D610-01. Evaluation 10 indicates that no rust has occurred, and indicates that the rust that has occurred in the order of 9, 8, 7, and 6 has progressed.

<Result>
The rust evaluation result according to ASTM standard D610-01 is shown in FIG.
Comparing the [Level 1] water-washing and blasting repair method with the [Level 2] water-washing-less method, the following results were obtained.
-In the 8.5th month evaluation, both [Level 1] and [Level 2] were evaluated as 9 for the composite membrane, and there was no difference in evaluation between the two levels.
-In the 10th month evaluation, both [Level 1] and [Level 2] were evaluated as 9 for the composite membrane, and there was no difference in evaluation between the two levels.
-In the 16th month evaluation, both [Level 1] and [Level 2] were evaluated as 9 for the composite membrane, and there was no difference in evaluation between the two levels.
In this way, it is considered that the [Level 2] water-washing-less method has the same or similar durability as the ideal repair method [Level 1] water-washing and blasting repair method. Will be.

<Test method>
The test material used in Example 2 was subjected to the same level 1 and level 2 treatments as in Example 2 to obtain test pieces. Then, a test was conducted on this test piece.
As a test method, a "shielded exposure test" was conducted for 16 months at an exposure test site in Okinawa Prefecture (area corresponding to C4 of ISO9223-92 corrosive classification). All of the specimens of the shielded exposure test were installed with the angle horizontal and the evaluation surface facing up. The shielded exposure test status is the same as in FIG. 3 (a).

<Evaluation method>
The appearance of the test piece after exposure was evaluated for rust according to ASTM standard D610-01. Evaluation 10 indicates that no rust has occurred, and indicates that the rust that has occurred in the order of 9, 8, 7, and 6 has progressed.

<Result>
FIG. 6 shows the rust evaluation results according to the ASTM standard D610-01.
Comparing the [Level 1] water-washing and blasting repair method with the [Level 2] water-washing-less method, the following results were obtained.
-In the 10th month evaluation, both [Level 1] and [Level 2] were evaluated as 9 for the composite membrane, and there was no difference in evaluation between the two levels.
-In the 16th month evaluation, both [Level 1] and [Level 2] were evaluated as 9 for the composite membrane, and there was no difference in evaluation between the two levels.

In this way, it is considered that the [Level 2] water-washing-less method has the same or similar durability as the ideal repair method [Level 1] water-washing and blasting repair method. Will be.

<Test method>
The test material used in Example 2 was subjected to the same level 1 and level 2 treatments as in Example 2 to obtain test pieces. Then, a test was conducted on this test piece.
As a test method, a "salt water spraying test" was carried out for 16 months in which a 0.2 wt% -NaCl aqueous solution was sprayed 5 times a week in a closed box. All the test pieces for the salt water spray test were installed with the angle horizontal and the evaluation surface facing up. The salt water spraying test situation is the same as in FIG. 3 (b).

<Evaluation method>
The appearance of the test piece after exposure was evaluated for swelling according to ASTM standard D714-02. Evaluation 10 indicates that no swelling has occurred, and indicates that the swelling that has occurred in the order of 8, 6, 4, and 2 has progressed.

<Result>
FIG. 7 shows the swelling evaluation results according to ASTM standard D714-02.
Comparing the [Level 1] water-washing and blasting repair method with the [Level 2] water-washing-less method, the following results were obtained.
-In the 8.5th month evaluation, both [Level 1] and [Level 2] were evaluated as 10 for the composite membrane, and there was no difference in evaluation between the two levels.
-In the 10th month evaluation, both [Level 1] and [Level 2] were evaluated as 10 for the composite membrane, and there was no difference in evaluation between the two levels.
-In the 16th month evaluation, both [Level 1] and [Level 2] were evaluated as 10 for the composite membrane, and there was no difference in evaluation between the two levels.
In this way, it is considered that the [Level 2] water-washing-less method has the same or similar durability as the ideal repair method [Level 1] water-washing and blasting repair method. Will be.

<Test method>
The test material used in Example 2 was subjected to the same level 1 and level 2 treatments as in Example 2 to obtain test pieces. Then, a test was conducted on this test piece.
As a test method, a "shielded exposure test" was conducted for 16 months at an exposure test site in Okinawa Prefecture (area corresponding to C4 of ISO9223-92 corrosive classification). All of the specimens of the shielded exposure test were installed with the angle horizontal and the evaluation surface facing up. The shielded exposure test status is the same as in FIG. 3 (a).

<Evaluation method>
The appearance of the test piece after exposure was evaluated for swelling according to ASTM standard D714-02. Evaluation 10 indicates that no swelling has occurred, and indicates that the swelling that has occurred in the order of 8, 6, 4, and 2 has progressed.

<Result>
FIG. 8 shows the swelling evaluation results according to ASTM standard D714-02.
Comparing the [Level 1] water-washing and blasting repair method with the [Level 2] water-washing-less method, the following results were obtained.
-In the 10th month evaluation, both [Level 1] and [Level 2] were evaluated as 10 for the composite membrane, and there was no difference in evaluation between the two levels.
-In the 16th month evaluation, both [Level 1] and [Level 2] were evaluated as 8 for the composite membrane, and there was no difference in evaluation between the two levels.
In this way, it is considered that the [Level 2] water-washing-less method has the same or similar durability as the ideal repair method [Level 1] water-washing and blasting repair method. Will be.

<Test method>
The test material used in Example 2 was subjected to the same level 1 treatment as in Example 2 to obtain a test piece. Further, another level 2 treatment (hereinafter, also referred to as “level 2 ′”), which differs only from the level 2 of Example 2 in the coating process, was performed to obtain a test piece. Then, the same test as in Example 2 was performed on these test pieces. The process flow of level 2'is summarized in FIG.
As a result of the test, the same result as in the case of Example 2 was obtained. That is, it is considered that the [Level 2'] water-washing-less method has the same or similar durability as the ideal repair method [Level 1] water-washing and blasting repair method. ..

Claims (3)

It is a repair painting method for steel structures.
The surface A of the corroded steel structure is treated so that the exposed area ratio of the base material is 30% or more, and the base material adjustment step of obtaining the base material adjusted surface B is performed.
A corrosion suppression step of applying a corrosion inhibitor containing hydrotalcite and / or hydrotalcite to the surface B to obtain a surface C coated with the corrosion inhibitor.
A polishing and grinding step of grinding or polishing the surface C to obtain a ground or polished surface D.
A paint application step of applying a zinc powder-containing paint to the surface D to obtain a surface F to which the zinc powder-containing paint is applied.
The painting process of applying paint to the surface F and
A water-washing-less repair method. The water-washing-less repair method according to claim 1, wherein the polishing and grinding step is performed by a blast treatment. The base material adjusting step has a metal rotating disk having a mounting portion at the center for attaching to the rotating shaft of the rotary drive device and a grinding surface composed of a grinding machine surface and a grinding peripheral surface, and the grinding surface of the metal rotating disk has. The water-washless repair according to claim 1 or 2 , which is carried out using a rotary grinding tool in which hard particles having a Morse hardness of more than 9 are waxed so as to have a surface density of 20 pieces / cm ² or more in part or all of them. Construction method.

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