Repair method for cement-based structures and two-component epoxy resin paint

Abstract

To provide a method for repairing a cement structure, capable of repairing even a cement structure to be repaired that is wet with water or contaminated with a contaminant such as oil. [Solution] The method for repairing a cement-based structure includes a cleaning step in which the surface of the cement-based structure to be repaired is cleaned with a cleaning solution containing a surfactant and an acidic solution, and a coating step in which the cleaned repaired surface is painted with a two-component epoxy resin paint consisting of an epoxy resin base containing an epoxy resin and an epoxy curing agent containing an amine-based curing agent and a curing accelerator. The curing accelerator for the epoxy curing agent is an imidazole derivative or imidazoline derivative having a hydroxy group.

Description

[Technical Field]

[0001] The present invention relates to a method for repairing cement-based structures and a two-component epoxy resin paint that adheres to cement-based structures. [Background technology]

[0002] Epoxy resin paints used for repairing cement-based structures such as concrete structures have been known for some time. Patent Document 1 describes an epoxy resin paint containing a liquid epoxy resin and an epoxy resin curing agent containing an aromatic amine, a specific aliphatic amine, and a curing accelerator. This epoxy resin paint has excellent adhesion to the cement-based structure to be repaired, even when the structure is wet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 088528 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the cement-based structures to be repaired are not only those that are wet with water, but also those that are contaminated with contaminants such as oil. The epoxy resin paint described in Patent Document 1 can repair cement-based structures that are wet with water, but there is a problem in that it may not be able to repair cement-based structures that are contaminated with contaminants such as oil.

[0005] In view of the above, an object of the present invention is to provide a method for repairing a cement-based structure that can repair a cement-based structure even if the cement-based structure to be repaired is wet with water or contaminated with contaminants such as oil. [Means for solving the problem]

[0006] A method for repairing a cement-based structure according to an embodiment of the present specification includes a cleaning step of cleaning a surface of the cement-based structure to be repaired with a cleaning liquid containing a surfactant and an acidic solution; a coating process for coating the cleaned repaired surface with a two-component epoxy resin paint comprising an epoxy resin base agent containing an epoxy resin and an epoxy curing agent containing an amine-based curing agent and a curing accelerator; A method for repairing a cement-based structure, comprising: The curing accelerator is characterized by being an imidazole derivative or imidazoline derivative having a hydroxy group.

[0007] According to the method for repairing a cement-based structure according to an embodiment of the present specification, in the cleaning step, an acidic solution of the cleaning liquid reacts with calcium carbonate in the cement-based structure to generate carbon dioxide gas. The generated carbon dioxide gas strips contaminants such as oil that have penetrated the interior of the cement-based structure from the cement-based structure. The stripped contaminants are lifted into the cleaning liquid by the surfactant in the cleaning liquid and then washed away. Next, in the coating step, the hydroxy groups of the imidazole derivative or imidazoline derivative contained in the epoxy curing agent cause the two-component epoxy resin paint to act as if it were partially hydrophilic. The hydrophilic two-component epoxy resin paint is absorbed by the hydroxy groups of the epoxy curing agent into the cementitious substance of the cementitious structure that has been wetted by the cleaning liquid, promoting adhesion to the cementitious substance. As the two-component epoxy resin paint hardens, the hydroxyl groups of the epoxy hardener react with the epoxy groups of the epoxy resin base, and the two-component epoxy resin paint also acts as an oleophilic (hydrophobic) paint, which adapts to cementitious structures contaminated by contaminants such as oil adhering to the interior of the cementitious structure, promoting adhesion to the contaminated cementitious structure. In other words, the method for repairing a cementitious structure of the embodiment can repair a cementitious structure that is wet with water or contaminated by contaminants such as oil.

[0008] In the repair method, the epoxy resin base may contain a fine filler.

[0009] This allows the viscosity of the epoxy resin base to be adjusted, improving the workability of the two-component epoxy resin paint.

[0010] In the repair method, the fine filler may be silica particles.

[0011] This allows the lipophilic portion of the epoxy resin to have an affinity with the silica particles, and when the two-component epoxy resin paint is applied to a cement-based structure, the dispersion and diffusion of the epoxy resin into a wet state is suppressed, thereby improving the adhesion of the two-component epoxy resin paint to the cement-based structure.

[0012] Here, the two-component epoxy resin paint of the embodiment is a two-component epoxy resin paint comprising an epoxy resin base agent containing an epoxy resin, and an epoxy curing agent containing an amine-based curing agent and a curing accelerator, The curing accelerator may be an imidazole or imidazoline derivative having a hydroxy group.

[0013] According to the two-component epoxy resin paint of the embodiment, the hydroxy groups of the imidazole derivative or imidazoline derivative contained in the epoxy curing agent cause the two-component epoxy resin paint to act partially hydrophilic, promoting adhesion to wet substrates. As the two-component epoxy resin paint cures, the hydroxy groups of the epoxy curing agent react with the epoxy groups of the epoxy resin base, causing the two-component epoxy resin paint to act lipophilic (hydrophobic), promoting adhesion to contaminants such as oil adhering to the substrate. In other words, the two-component epoxy resin paint of the embodiment can achieve adhesion even to wet substrates or substrates with contaminants such as oil adhering to them. [Effects of the Invention]

[0014] According to the embodiment of the method for repairing a cement-based structure, the cement-based structure to be repaired can be repaired even if it is wet with water or contaminated with contaminants such as oil attached. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of a method for repairing a cement-based structure will be described. The method for repairing a cement-based structure of this embodiment includes a cleaning step of cleaning the surface of the cement-based structure to be repaired using a cleaning solution containing a surfactant and an acidic solution, and a coating step of painting the cleaned repaired surface with a two-component epoxy resin paint consisting of an epoxy resin base containing an epoxy resin, and an epoxy curing agent containing an amine-based curing agent and a curing accelerator. The curing accelerator for the epoxy curing agent is an imidazole derivative or imidazoline derivative having a hydroxy group.

[0016] When the hardening accelerator is an imidazole derivative or imidazoline derivative having a hydroxy group, the two-component epoxy resin paint acts as a hydrophilic agent in the early stage of the reaction, and adheres to the cementitious substance of a wet cement-based structure. As the hardening progresses, the two-component epoxy resin paint acts as a lipophilic agent, and becomes familiar with a cement-based structure contaminated by contaminants such as oil remaining and adhering to the inside of the cement-based structure, and adhesion to the contaminated cement-based structure is promoted.

[0017] The two-component epoxy resin coating material of the embodiment is composed of an epoxy resin base agent containing an epoxy resin, and an epoxy curing agent containing an amine-based curing agent and a curing accelerator.

[0018] The epoxy resin contained in the epoxy resin base is a compound or polymer compound having two or more epoxy groups in one molecule. Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, tetrabromobisphenol A type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenyl benzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl disulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, and methylhydroquinone type epoxy resin. Bifunctional epoxy resins such as dibutylhydroquinone-type epoxy resins, resorcinol-type epoxy resins, methylresorcinol-type epoxy resins, and catechol-type epoxy resins; trifunctional epoxy resins such as N,N-diglycidylaminobenzene-type epoxy resins and triazine-type epoxy resins; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane-type epoxy resins and diaminobenzene-type epoxy resins; multifunctional epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, triphenylmethane-type epoxy resins, tetraphenylethane-type epoxy resins, dicyclopentadiene-type epoxy resins, naphthol aralkyl-type epoxy resins, and brominated phenol novolac-type epoxy resins; and alicyclic epoxy resins can be used. These can be used alone or in combination of two or more. Furthermore, epoxy resins modified with isocyanates or the like can also be used. In another embodiment, the epoxy resin may be a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AD ​​type epoxy resin, a bisphenol M type epoxy resin, or a bisphenol P type epoxy resin, which have excellent adhesion to cement-based structures. In yet another embodiment, a bisphenol A type epoxy resin may be used.

[0019] The epoxy resin base can contain fine fillers, which adjust the viscosity of the epoxy resin base and improve the workability of the two-component epoxy resin paint.

[0020] The fine filler of the embodiment is a filler (filling material) having an average primary particle diameter of 5 to 100 nm. Examples of fillers having an average primary particle diameter of 5 to 100 nm include silica particles, calcium carbonate particles, metal particles, and ceramic particles. In another embodiment, the fine filler may be silica particles, and fumed silica or aerosil may be used as the silica particles. By incorporating silica particles into a two-component epoxy resin coating material, the lipophilic portion of the epoxy resin and the silica particles become compatible with each other. When the two-component epoxy resin coating material is applied to a cement-based structure, the dispersion and diffusion of the epoxy resin into a wet state is suppressed, and the two-component epoxy resin coating material can have improved adhesion to cement-based structures.

[0021] The epoxy curing agent is used to cure the epoxy resin and contains an amine-based curing agent and a curing accelerator.

[0022] The amine-based curing agent contained in the epoxy curing agent is a compound that can crosslink with the epoxy resin to cure the epoxy resin. Examples of the amine-based curing agent that can be used include aliphatic amine-based curing agents, aromatic amine-based curing agents, polyamidoamine-based curing agents, and polyamine-based curing agents.

[0023] Examples of aliphatic amine curing agents that can be used include diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, 1,2-diaminocyclohexane, and 1,8-diazabicyclo(5,4,0)undecene-7 (DBU).

[0024] Examples of aromatic amine curing agents that can be used include diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, trimethylenebis(4-aminobenzoate), and polytetramethyleneoxide-di-p-aminobenzoate.

[0025] The curing accelerator contained in the epoxy curing agent is a compound that does not crosslink itself when curing an epoxy resin, but accelerates the crosslinking reaction of the curing agent. As the curing accelerator of the embodiment, an imidazole derivative or imidazoline derivative having a hydroxy group can be used.

[0026] Examples of imidazole derivatives having a hydroxy group that can be used include 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole, 4(5)-hydroxymethyl)imidazole, 1-(2-hydroxyethyl)imidazole, 1-(3-hydroxypropyl)imidazole, 2-hydroxybenzimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0027] Examples of imidazoline derivatives having a hydroxy group that can be used include 1-(2-hydroxyethyl)imidazoline, 1-(3-hydroxypropyl)imidazoline, cocoyl hydroxyethyl imidazoline, and hydroxyethyl diphenyl imidazoline.

[0028] Curing accelerators with hydroxyl groups can adhere to the surface of cement-based structures when the hydroxyl groups are wet. Furthermore, the hydroxyl groups of the curing accelerator react with the epoxy groups of the epoxy resin base, separating water (H2O). The separated water has a cleaning effect on the interface of cement-based structures. In two-component epoxy resin paints from which the water has separated, the binder resin acts as if it has lipophilic (hydrophobic) properties. Lipophilic two-component epoxy resin paints are adsorbed to contaminants such as oil that remain and stick inside cement-based structures, promoting adhesion even to contaminated cement-based structures.

[0029] The two-component epoxy resin paint of the embodiment can be produced by mixing an epoxy resin and a fine filler to form the epoxy resin base, and by mixing an amine-based curing agent and a curing accelerator to form the epoxy curing agent. By mixing the epoxy resin base and the epoxy curing agent, they become a two-component epoxy resin paint formed from two components. Note that the two-component epoxy resin paint can be diluted by adding a dilution solvent to adjust the viscosity.

[0030] Examples of dilution solvents that can be used include isopropyl alcohol, acetone, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, propylene glycol phenyl ether, diethylene glycol dimethyl ether, diacetone alcohol, etc. These can be used alone or in combination of two or more.

[0031] The cleaning solution of the embodiment is a solution for cleaning the repaired surface of a cement-based structure, and is made by adding a surfactant and an acidic solution to water. The acidic solution reacts with calcium carbonate in the cement-based structure to generate carbon dioxide gas, which has the effect of removing contaminants such as oil that have penetrated the interior of the cement-based structure from the cement-based structure. The removed contaminants such as oil are floated into the cleaning solution by the surfactant in the cleaning solution and are then cleaned away.

[0032] Specifically, the cleaning solution of the embodiment reacts with calcium carbonate in the cement-based structure to generate carbon dioxide gas. During the carbon dioxide gas generation process, most of the oil and other contaminants that have entered the capillaries of the cement-based structure are lifted and removed by the surfactant. However, some of the oil and other contaminants that have entered the capillaries are sealed at the top by the water in the cleaning agent, preventing them from lifting. This phenomenon occurs because the surface tension of oil and other contaminants in the capillaries is lower than that of water.

[0033] In the process of generating carbon dioxide gas by washing with the cleaning solution, most of the oil and other contaminants that have entered the capillaries of the cementitious structure are lifted up and removed by the surfactant, and the surface of the cementitious structure is wetted by the water in the cleaning water. At this time, the hydroxy group of the imidazole derivative or imidazoline derivative contained in the epoxy curing agent can adhere to the wet surface of the cementitious structure, and the two-component resin paint of the embodiment can adhere to the wet surface of the cementitious structure.

[0034] If the surface of a cement-based structure is not wet and most of the water in the cleaning solution evaporates, the water seal at the top of the capillaries will break, and contaminants such as oil that have entered the capillaries will float to the surface of the cement-based structure. The floating contaminants will hinder the adhesion of two-component epoxy resin paint to the surface of the cement-based structure. For this reason, the surface of the cement-based structure must be kept wet.

[0035] If the cleaning solution does not contain an acidic solution, it will be unable to generate carbon dioxide gas. Also, if the cleaning solution does not contain a surfactant, it will be unable to lift and remove contaminants such as oil that have entered the capillaries of the cement-based structure during the process of generating carbon dioxide gas.

[0036] The acidic solution may be, for example, a hydrochloric acid solution, a nitric acid solution, a diluted sulfuric acid solution, etc. In another embodiment, a hydrochloric acid solution may be used, which is easy to handle.

[0037] The surfactant may be a nonionic surfactant that can be used even in an acidic environment, such as polyoxyethylene alkyl ether or polyoxyalkylene derivative.

[0038] The cleaning solution of this embodiment can be produced by mixing an acidic solution and a surfactant with water. The acidic solution is added in an amount that makes the pH of the cleaning solution 0 to 2. The surfactant is added in an amount that makes the amount of the surfactant 5 to 15% by mass of the cleaning solution.

[0039] Next, a method for repairing a cement-based structure according to an embodiment will be described. The method for repairing a cement-based structure includes a cleaning process for cleaning the surface of the cement-based structure to be repaired using a cleaning liquid, a coating process for painting the cleaned surface with a two-component epoxy resin paint, and a finishing process for painting a finishing paint on the surface that has been painted with the two-component epoxy resin paint.

[0040] The repair method of the embodiment can repair not only cementitious structures that are wet with water, but also those that are contaminated with contaminants such as oil.

[0041] The cleaning process involves spraying a cleaning solution onto the surface of the cement structure to be renovated, and then brushing and cleaning the surface using a deck brush or the like.

[0042] In the cleaning process, the acidic solution of the cleaning liquid reacts with the calcium carbonate of the cement-based structure to generate carbon dioxide gas, which then removes contaminants such as oil that have penetrated the cement-based structure. The removed contaminants are then lifted into the cleaning liquid by the surfactants in the cleaning liquid and washed away.

[0043] The painting process involves applying a two-component epoxy resin paint to the cleaned, wet repaired surface using a wool roller, etc. Two-component epoxy resin paint is made ready for painting by mixing the epoxy resin base and epoxy hardener just before painting.

[0044] During the painting process, the hydroxyl groups of the imidazole or imidazoline derivatives contained in the epoxy curing agent cause a portion of the binder resin of two-component epoxy resin paint to act as hydrophilic in the early stages after painting. The hydrophilic two-component epoxy resin paint blends with the cementitious substance of the wet cementitious structure due to the cleaning solution, promoting adhesion to the cementitious substance. As the two-component epoxy resin paint hardens, the hydroxyl groups of the epoxy curing agent's accelerator react with the epoxy groups of the epoxy resin base, separating water (H2O). The separated water exerts a cleaning effect on the interface of the cementitious structure. Once the water has separated from the two-component epoxy resin paint, the binder resin acts as an oleophilic (hydrophobic) substance. The oleophilic two-component epoxy resin paint blends with contaminants such as oil remaining inside the cementitious structure, promoting adhesion to even contaminated cementitious structures.

[0045] The finishing process involves applying a finishing paint to the repaired surface, which has been coated with a two-component epoxy resin paint, using a wool roller or plastering trowel. General-purpose finishing paints can be used, including those specified in architectural finishing coating materials (JIS A 6909), architectural waterproof coating materials (JIS A 6021), glossy synthetic resin emulsion paints (JIS K 5660), synthetic resin emulsion paints and sealers (JIS K 5663), architectural weather-resistant topcoats (JIS K 5658), and epoxy resins for architectural repair and reinforcement (JIS A 6024). [Example]

[0046] The raw materials used for the two-component epoxy resin paint (epoxy resin base and epoxy curing agent) and cleaning solution of the examples are listed below.

[0047] Epoxy resin Bisphenol A epoxy resin (EP-4520S (ADEKA Corporation)) (Epoxy equivalent: 200g / eq, viscosity: 1000mPa·s) Fine filler Fumed silica (Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.)) Amine-based hardener Aliphatic amine (EH-6019 (ADEKA Corporation triethylenetetramine)) (Amine value: 430 KOHmg / g, viscosity: 1200 mPa·s) Aromatic amine (JerCure WA (diaminodiphenylmethane manufactured by Mitsubishi Chemical Corporation)) (Amine value: 630 KOHmg / g, viscosity: 165 mPa·s) Polyamidoamine (Polymide L-4051 (manufactured by Sanyo Chemical Industries, Ltd.)) (Amine value: 345 KOHmg / g, viscosity: 300 mPa·s) Curing accelerator Imidazole derivatives (1-(2-hydroxyethyl)imidazole) surfactants Nonionic surfactant (polyoxyethylene alkyl ether) acidic solution Hydrochloric acid (35% hydrogen chloride) These are commercially available products.

[0048] The two-component epoxy resin paints (epoxy resin base and epoxy curing agent) of the examples were subjected to the evaluation tests described below.

[0049] <Adhesion strength test> The standard conditions for the bond strength test were in accordance with JIS A 6909:2014 (Architectural Finish Coating Materials) 7.10 Bond Strength Test. The substrates used were prepared according to JIS K 5600-1-4:2004 (General Test Methods for Paints - Part 1: General Provisions - Section 4: Standard Test Version for Testing) 5.10 Cement Mortar Board. For the wet condition, the substrate (cement mortar board) was cured in water for 7 days, then cleaned with the cleaning solution and brush listed in Table 1 (cleaning process), and immediately after cleaning, the substrate was painted with a two-component epoxy resin paint (painting process). The rest of the procedure was the same as for the standard condition. For the contaminated condition, the substrate was immersed in motor oil (SEA5-20) for 7 days, then cleaned with the cleaning solution and brush listed in Table 1 (cleaning process), and immediately after cleaning, the substrate was painted with a two-component epoxy resin paint (painting process). The rest of the procedure was the same as for the standard condition. And the adhesive strength is 1.0N / mm 2 0.7N / mm or more: ○ 2 More than 1.0N / mm 2 Less than 0.7N / mm 2 If the value was less than this, it was evaluated as x.

[0050] [Table 1]

[0051] <Compression strength test> The compressive strength test was carried out in accordance with JIS A 6916:2014 (construction surface preparation coating materials) 7.12 compressive strength test.2 7N / mm or more: ○ 2 More than 10N / mm 2 Less than 7N / mm 2 If the value was less than this, it was evaluated as x.

[0052] <Dispersibility in wet conditions> Dispersibility in wet conditions was judged by the state of the two-component epoxy resin paint when it was applied in a wet state in the adhesion strength test. The two-component epoxy resin paint that was applied was evaluated as ○ if it was incompatible (repellent) with water (washing water), △ if it was compatible but did not cause any problems with the coating performance, and × if it was compatible but showed abnormalities in the coating such as blisters.

[0053] The formulations of the two-component epoxy resin paints (epoxy resin base and epoxy curing agent) of the test examples and the test results are shown in Tables 2 and 3. Test Examples 1 to 5 and Test Examples 9 to 13 are working examples, and Test Examples 6 to 8 and Test Examples 14 to 16 are comparative examples.

[0054] [Table 2]

[0055] [Table 3]

[0056] (Test Examples 1 to 5) Test Examples 1 to 5 are test examples in which a bisphenol A type epoxy resin was used as the epoxy resin and an imidazole derivative was used as the epoxy curing agent accelerator, and the type of amine-based curing agent was changed. The amine-based curing agent used was an aliphatic amine in Test Example 1, an aromatic amine in Test Example 2, a polyamidoamine in Test Example 3, an aliphatic amine and an aromatic amine in Test Example 4, and an aromatic amine and a polyamidoamine in Test Example 5. Test Examples 1 to 5 were not inferior to the standard conditions in the wet and contaminated conditions in the bond strength test, and achieved an bond strength of 1.0 N / mm 2The results were as above. In a wet state, the hydroxyl groups of the imidazole derivative contained in the epoxy hardener make the two-component epoxy resin paint partially hydrophilic, blending with the cementitious substance of the wet cementitious structure and promoting adhesion to the cementitious substance. In a contaminated state, the acidic solution of the cleaning liquid reacts with the calcium carbonate of the cementitious structure during the cleaning process to generate carbon dioxide, which is presumably responsible for removing oil contaminants that have penetrated the interior of the cementitious structure from the structure. In a contaminated state, as the two-component epoxy resin paint hardens, the hydroxyl groups of the epoxy hardener react with the epoxy groups of the epoxy resin base, causing the two-component epoxy resin paint to act as an oleophilic (hydrophobic) substance, blending with the cementitious structure contaminated by oil and other contaminants adhering to the interior of the cementitious structure and promoting adhesion to the contaminated cementitious structure. In a compressive strength test, the compressive strength was 10 N / mm 2 As for dispersibility in a wet state, the two-component epoxy resin paint applied was found to be compatible with water (washing water), but this did not cause any problems with the coating film performance.

[0057] (Test Examples 6 to 8) Test Examples 6 to 8 are test examples in which the imidazole derivative, which is an epoxy curing agent effect accelerator, was not blended in from Test Examples 1 to 3. Compared to Test Examples 1 to 3, Test Examples 6 to 8 had an adhesive strength of 0.7 N / mm under all conditions. 2 The results were less than 7N / mm. It is presumed that the absence of a hydroxy group in the imidazole derivatives means that Test Examples 6 to 8 do not blend with the wet cementitious material of the cementitious structure, do not react with the epoxy group of the epoxy resin base, do not act as lipophilic (hydrophobic), and do not blend with the contaminated cementitious structure, resulting in poor adhesion. The compressive strength test showed a result of less than 7N / mm, although the reason is unclear. 2 As for dispersibility in a wet state, similar to Test Examples 1 to 3, the two-component epoxy resin paint applied was found to be compatible with water (washing water), but this did not cause any problems in the coating film performance.

[0058] (Test Examples 9-16) Test Examples 9 to 16 were prepared by adding fumed silica as a fine filler to the epoxy resin base of Test Examples 1 to 8. The two-component epoxy resin paints of Test Examples 9 to 16 had an affinity between the lipophilic portion of the epoxy resin and the silica particles, and when the two-component epoxy resin paints were applied to cement-based structures, the dispersion and diffusion of the epoxy resin into a wet state was inhibited, and the applied two-component epoxy resin paint was incompatible with (repelled by) water. It is assumed that the two-component epoxy resin paints of Test Examples 9 to 16 can improve adhesion to cement-based structures, but no clear difference was confirmed in this test.

[0059] (Other technical ideas) Other technical concepts that can be understood from the method for repairing a cement-based structure or the two-component epoxy resin paint of the embodiment configured as described above will be described below.

[0060] The above-mentioned method for repairing a cement-based structure may further include a finishing step of applying a finishing paint to the repaired surface that has been painted with the two-component epoxy resin paint.

[0061] This can increase the durability of the renovated cementitious structure.

[0062] Furthermore, in the above-mentioned method for repairing a cement-based structure, the finishing paint may be a finishing paint specified in architectural finishing coating materials (JIS A 6909), architectural waterproof coating materials (JIS A 6021), glossy synthetic resin emulsion paints (JIS K 5660), glossy synthetic resin emulsion paints and sealers (JIS K 5663), architectural weather-resistant topcoats (JIS K 5658), or epoxy resins for architectural repair and reinforcement (JIS A 6024).

[0063] This can increase the durability of the renovated cementitious structure.

Claims

1. a cleaning step of cleaning the surface of the cement-based structure to be repaired with a cleaning solution containing a surfactant and an acidic solution; a coating process for coating the cleaned repaired surface with a two-component epoxy resin paint comprising an epoxy resin base agent containing an epoxy resin and an epoxy curing agent containing an amine-based curing agent and a curing accelerator; A method for repairing a cement-based structure, comprising: The method for repairing a cement-based structure is characterized in that the hardening accelerator is an imidazole derivative or imidazoline derivative having a hydroxy group.

2. 2. The method for repairing a cement-based structure according to claim 1, wherein the epoxy resin base contains a fine filler.

3. 3. The method for repairing a cement-based structure according to claim 2, wherein the fine filler is silica particles.

4. A two-component epoxy resin paint comprising an epoxy resin base agent containing an epoxy resin and an epoxy curing agent containing an amine-based curing agent and a curing accelerator, The two-component epoxy resin paint is characterized in that the curing accelerator is an imidazole derivative or imidazoline derivative having a hydroxy group.

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