Crack repair composition and crack repair method

Abstract

To provide a crack repairing material composition and a crack repairing method that can enhance the durability of structures with metal reinforcement.SOLUTION: A repair method for repairing cracks in structures with metal reinforcement includes a step to prepare first and second crack repairing material compositions that contain epoxy resin and a rust preventive agent and have different viscosities when prepared, and a step to inject the first crack repairing material composition 31 into the cracks of the structure from the surface of the structure toward the back and then inject the second crack repairing material composition. The first crack repairing material composition has a lower viscosity than the second crack repairing material composition, and the content rate of the rust preventive agent in the first crack repairing material composition is higher than the content rate of the rust preventive agent in the second crack repairing material composition.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a crack repair material composition and a crack repair method. [Background technology]

[0002] For example, in concrete structures, cracks may occur in the concrete skeleton due to expansion and contraction of the concrete skeleton caused by changes in environmental temperature. One method of repairing cracks is to inject epoxy-based, cement-based or other repair materials into the cracks (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-139858 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of structures containing metal reinforcement, such as reinforced concrete structures, it has sometimes been difficult to increase the durability of the structures using the repair materials.

[0005] An object of one aspect of the present invention is to provide a crack repair material composition and a crack repair method that can increase the durability of a structure containing a metal reinforcing material. [Means for solving the problem]

[0006] One aspect of the present invention provides a crack repair material composition containing an epoxy resin and a rust inhibitor.

[0007] The rust inhibitor preferably includes mineral oil, sorbitan fatty acid ester, and petroleum sulfonate.

[0008] Another aspect of the present invention provides a crack repair method, which comprises injecting a crack repair material containing an epoxy resin and a rust inhibitor into cracks in a structure containing a metal reinforcement material.

[0009] The crack repair method may include preparing a plurality of crack repair materials each having a different viscosity when prepared, injecting a first crack repair material from the plurality of crack repair materials into the crack, and then injecting a second crack repair material from the plurality of crack repair materials, the second crack repair material having a higher viscosity than the first crack repair material, into the crack.

[0010] The amount of the rust inhibitor mixed in the first crack repair material is preferably greater than the amount of the rust inhibitor mixed in the second crack repair material. Effect of the Invention

[0011] According to one aspect of the present invention, there is provided a crack repair material composition and a crack repair method capable of increasing the durability of a structure containing a metal reinforcing material. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing an example of a structure containing metal reinforcement to which the crack repair method of the embodiment can be applied. FIG. [Diagram 2] FIG. 1 is a perspective view illustrating a repair method according to a first embodiment. [Diagram 3] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 4] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Diagram 5] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 6] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 7] FIG. 2 is a cross-sectional view illustrating a repair method according to the first embodiment. [Figure 8] FIG. 11 is a cross-sectional view illustrating a repair method following the previous figure. [Figure 9]FIG. 11 is a cross-sectional view illustrating a repair method following the previous figure. [Figure 10] FIG. 11 is a cross-sectional view illustrating a repair method following the previous figure. [Figure 11] FIG. 11 is a perspective view illustrating a repair method according to a second embodiment. [Figure 12] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 13] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 14] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 15] FIG. 11 is a perspective view illustrating a repair method following the previous figure. [Figure 16] FIG. 11 is a perspective view illustrating a repair method following the previous figure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a crack repair material composition and a crack repair method according to an embodiment will be described in detail with reference to the drawings.

[0014] [Metal reinforced structure] FIG. 1 is a perspective view showing an example of a structure containing metal reinforcement to which the crack repair method of the embodiment can be applied. The reinforced concrete structure 10 shown in Fig. 1 is a reinforced concrete (RC) structure, and is a specific example of a structure containing metal reinforcement. The reinforced concrete structure 10 is a wall erected on a base 11. The reinforced concrete structure 10 comprises internal reinforcing bars 12 and a concrete skeleton 13. The internal reinforcing bars 12 are embedded inside the concrete skeleton 13. The internal reinforcing bars 12 comprise vertical reinforcing bars 14 extending in the height direction of the reinforced concrete structure 10, and horizontal reinforcing bars 15 extending in a direction perpendicular to the vertical reinforcing bars 14. The internal reinforcing bars 12 are an example of a metal reinforcement.

[0015] A crack 20 (fissure) is formed in the concrete body 13 of the reinforced concrete structure 10. The crack 20 is formed from the first main surface 10a of the reinforced concrete structure 10 toward the inside of the reinforced concrete structure 10. The crack 20 is formed when the concrete body 13 expands due to, for example, a change in the environmental temperature or a change in the moisture content of the concrete body 13. The cracks 20 are caused by the expansion and contraction of the concrete body 13. For example, the cracks 20 are formed when the concrete body 13 is divided by the tensile stress caused by the expansion and contraction of the concrete body 13. The cracks 20 include defects and flaws formed in the concrete body 13. The cracks 20 reach the internal reinforcing bars 12, for example.

[0016] [Crack repair composition] The crack repair material composition of the embodiment contains an epoxy resin and a rust inhibitor. The epoxy resin may be a two-liquid type or a one-liquid type. The two-liquid type epoxy resin is prepared by mixing a base agent and a curing agent. The base agent is produced, for example, by polymerization of bisphenol A and epichlorohydrin. The base agent has two or more epoxy groups in one molecule. The base agent includes, for example, a phenol novolac type epoxy resin, n-butyl-2,3-epoxypropyl ether, and a reactive diluent. The reactive diluent has a lower viscosity than the viscosity of the epoxy resin when it is prepared (the viscosity immediately after the base agent and the curing agent are mixed). The base agent may be mixed with silica.

[0017] Examples of the curing agent include amine compounds, organic acids, acid anhydrides, etc. Examples of the amine compounds include tetraethylenepentamine, diethylenetriamine, modified aliphatic polyamines, aliphatic polyamines, metaxylylenediamine, polyamidoamine, etc. These amine compounds may be used alone or in combination of two or more.

[0018] The curing agent may contain phenols. Examples of phenols include 2,4-di-tert-butylphenol, phenol, cresol, etc. These phenols may be used alone or in combination of two or more.

[0019] Examples of the rust inhibitor include mineral oils, esters, petroleum sulfonates, carboxylic acids, nitrogen compounds, phosphates, and thiophosphates. Examples of mineral oils include paraffinic mineral oils and naphthenic mineral oils. Examples of esters include sorbitan fatty acid esters and pentaerythritol monooleate. Examples of sorbitan fatty acid esters include sorbitan monoisostearate and sorbitan monooleate. Examples of petroleum sulfonates include calcium petroleum sulfonate, sodium petroleum sulfonate, and barium petroleum sulfonate. Examples of carboxylic acids include alkali metal salts of aliphatic carboxylic acids, alkali metal salts of alkenyl succinic acids, and alkali metal salts of aromatic carboxylic acids. Examples of nitrogen compounds include dicyclohexyl ammonium nitrite and diisopropyl ammonium nitrite.

[0020] Rust occurs, for example, due to oxidation reactions caused by electrical and chemical effects on the metal surface. It can be assumed that rust inhibitors suppress the generation of rust, for example, due to the following effects. Rust inhibitors are adsorbed onto the surface of the target metal (e.g., the internal rebar 12), suppressing the adsorption of water and oxygen, and making the metal less likely to ionize. Therefore, the rust inhibitor reduces the reactivity of the metal (e.g., the internal rebar 12), and can suppress the generation of rust.

[0021] The rust inhibitor preferably contains at least a mineral oil, a sorbitan fatty acid ester, and a petroleum sulfonate, which can enhance the rust-preventing effect in reinforced concrete structures. The amount of the rust inhibitor to be added to the epoxy resin may be, for example, 0.5 to 10 parts by mass (preferably 0.5 to 5 parts by mass) per 100 parts by mass of the epoxy resin. It is preferable to mix the rust inhibitor with the hardener in advance, which makes it easier to prepare the crack repair material at the construction site.

[0022] [Crack repair method] (First embodiment) Figures 2 to 6 are perspective views for explaining the crack repair method according to the first embodiment (hereinafter, may be simply referred to as the repair method). Figures 7 to 10 are cross-sectional views for explaining the repair method according to the first embodiment. Hereinafter, the crack repair method of the embodiment will be described with reference to Figures 2 to 10.

[0023] (Cleaning process) As shown in FIG. 2, on the surface (first main surface 10a) of the reinforced concrete structure 10, a strip area including the crack 20 (a strip area along the crack 20) ​​is cleaned to remove foreign matter and the like.

[0024] (Sealing process) As shown in FIG. 3, a temporary sealant 21 is applied to the band-like region along the crack 20. In the region where the temporary sealant 21 is applied, the crack 20 is covered, and the opening of the crack 20 is blocked. As shown in FIG. 3 and FIG. 7, the temporary sealant 21 is not applied to an injection point 22 which is part of the band-like region. At the injection point 22, a crack repair material is injected into the crack 20 in a process described later. There may be one injection point 22, or multiple injection points 22. The multiple injection points 22 are secured at intervals in a direction along the crack 20.

[0025] As shown in Figs. 4 and 8, an injection tool 23 for injecting the crack repair material is attached to the injection location 22. The injection tool 23 includes a mounting seat 25 and an injection pipeline 26. The mounting seat 25 is formed in a disk shape. The injection pipeline 26 extends from one surface of the mounting seat 25 in a direction perpendicular to the mounting seat 25. The injection pipeline 26 and the mounting seat 25 have an internal flow path through which the crack repair material flows. The mounting seat 25 of the injection tool 23 is adhered to the first main surface 10a by the temporary sealing material 21. As shown in FIGS. 5 and 6, a pressure tank 28 is attached to the injection line 26 via a branch line 27.

[0026] (Injection process) The above-mentioned crack repair material composition is prepared. When a two-liquid type epoxy resin is used, the base agent and the curing agent are mixed together immediately before injection into the crack 20 to obtain the crack repair material composition. The base agent and the curing agent are mixed together to produce an epoxy resin. A rust inhibitor is mixed into the crack repair material composition. When the curing agent is mixed with a rust inhibitor in advance, the base agent and the curing agent are mixed together to obtain a crack repair material composition containing an epoxy resin and a rust inhibitor.

[0027] As shown in FIG. 5, the crack repair material composition is filled into the storage section 30a of the injection pump 30 as the crack repair material 31. The injection pump 30 injects the crack repair material 31 into the crack 20 through the injection tool 23. As shown in FIG. 9, the crack repair material 31 passes through the internal flow path of the injection tool 23 and enters the crack 20. The crack repair material 31 spreads throughout the crack 20, and some of it reaches the internal rebar 12. Some of the crack repair material 31 covers the surface of the internal rebar 12. The rust inhibitor contained in the crack repair material 31 acts on the internal rebar 12. As shown in FIG. 5, the temporary sealing material 21 prevents the crack repair material 31 from spilling out of the crack 20.

[0028] As shown in FIG. 6, after the crack repair material 31 is injected into the crack 20 through the injection tool 23, the tip of the injection pipe 26 is closed. When the crack repair material 31 is injected, a part of the crack repair material 31 flows into the pressure tank 28. This causes the internal pressure of the pressure tank 28 to increase. Therefore, the crack repair material 31 in the pressure tank 28 is injected into the cracks 20 through the injection line 26 at a stable flow rate even after the injection line 26 is closed. By leaving it for a predetermined time, the crack repair material 31 in the cracks 20 hardens. As shown in FIG. 10, after the crack repair material 31 has hardened, the temporary fixing sealant 21 and the injection tool 23 are removed.

[0029] The crack repair material composition contains a rust inhibitor, so that the rust inhibitor can act on the internal reinforcing bars 12 in the cracks 20. This makes it possible to inhibit the occurrence of rust in the internal reinforcing bars 12. This makes it possible to increase the durability of the reinforced concrete structure 10.

[0030] The crack repair method uses a crack repair material composition containing a rust inhibitor, so that the rust inhibitor can act on the internal reinforcing bars 12 in the cracks 20. This makes it possible to suppress the occurrence of rust in the internal reinforcing bars 12. This makes it possible to increase the durability of the reinforced concrete structure 10.

[0031] [Crack repair method] (Second embodiment) Next, a crack repair method according to a second embodiment will be described. In the crack repair method according to the second embodiment, a plurality of crack repair materials having different viscosities when prepared (viscosity immediately after mixing the main agent and the curing agent) are used. For example, three crack repair materials (first to third crack repair materials) having different viscosities when prepared can be used. The second crack repair material has a higher viscosity than the first crack repair material. The third crack repair material has a higher viscosity than the second crack repair material.

[0032] The viscosity of the crack repair material can be adjusted by adjusting the amount of reactive diluent in the base material. For example, by increasing the amount of reactive diluent, the viscosity of the crack repair material can be reduced. By decreasing the amount of reactive diluent, the viscosity of the crack repair material can be increased. It is preferable that the amount of reactive diluent in the base material of the second crack repair material is smaller than that of the first crack repair material. It is preferable that the amount of reactive diluent in the base material of the third crack repair material is smaller than that of the second crack repair material.

[0033] The viscosity of the first crack repair material when prepared may be, for example, 100 to 500 mPa·s (23°C). The viscosity of the second crack repair material when prepared may be, for example, 440 to 840 mPa·s (23°C). The viscosity of the third crack repair material when prepared may be, for example, 5000 to 15000 mPa·s (23°C).

[0034] The hardener of the second crack repair material may contain tetraethylenepentamine as an amine compound.The hardener of the second crack repair material may use 2,4-di-tert-butylphenol as a phenol.

[0035] It is preferable that the first crack repair material has a higher amount (or content) of rust inhibitor than the second crack repair material. The second crack repair material may have a higher amount (or content) of rust inhibitor than the third crack repair material. For example, the amount C1 of rust inhibitor in the first crack repair material, the amount C2 of rust inhibitor in the second crack repair material, and the amount C3 of rust inhibitor in the third crack repair material may satisfy "C1>C2>C3".

[0036] 11 to 15 are perspective views illustrating the repair method according to the second embodiment.

[0037] (Cleaning process) As shown in FIG. 11, on the surface (first main surface 10a) of the reinforced concrete structure 10, The strip containing the crack 20 is cleaned.

[0038] (Sealing process) As shown in FIG. 12, a temporary fixing sealant 21 is applied to a strip-shaped area including the crack 20 along the crack 20 while leaving an injection point 22 . As shown in FIG. 13, an injection tool 23 for injecting the crack repair material is attached to the injection point 22.

[0039] (1st injection process) The first crack repair material 131 is obtained by mixing the base agent and the hardener. 14, a first crack repair material 131 is injected into the crack 20 by an injection pump 30. The first crack repair material 131 has a low viscosity, so that it easily spreads throughout the crack 20.

[0040] (Second injection process) The base agent and the hardener are mixed to obtain the second crack repair material 132. 15, the second crack repair material 132 is injected into the crack 20 by the injection pump 30. Since the second crack repair material 132 has a higher viscosity than the first crack repair material 131, even if an unfilled space remains in the crack 20 in the first injection step, the second crack repair material 132 can fill this space.

[0041] (Third injection process) The base agent and the hardener are mixed to obtain the third crack repair material 133. As shown in Fig. 16, the third crack repair material 133 is injected into the crack 20 by the injection pump 30. Since the third crack repair material 133 has a higher viscosity than the second crack repair material 132, even if an unfilled space remains in the crack 20 in the second injection step, the third crack repair material 133 can fill this space.

[0042] After the crack repair materials 131 to 133 have hardened, the temporary fixing sealant 21 and the injection tool 23 are removed.

[0043] The crack repair method involves injecting a first crack repair material 131 into the crack 20, then injecting a second crack repair material 132 having a higher viscosity than the first crack repair material 131 into the crack 20, and then injecting a third crack repair material 133 having a higher viscosity than the second crack repair material 132 into the crack 20.

[0044] In the first injection step, the first crack repair material 131 has a low viscosity, so it penetrates even narrow parts of the crack 20 and spreads throughout the entire crack 20. The first crack repair material 131 spreads over a wide area on the surface of the internal rebar 12. The first crack repair material 131 has a high content of rust inhibitor, so it can improve the rust prevention effect of the internal rebar 12. Therefore, the durability of the reinforced concrete structure 10 can be improved.

[0045] In the second injection step, since the high-viscosity second crack repair material 132 is used, even if an unfilled space remains in the crack 20 in the first injection step, this space can be filled. In the third injection step, since the high-viscosity third crack repair material 133 is used, even if an unfilled space remains in the crack 20 in the second injection step, this space can be filled. According to the second injection step and the third injection step, even if the crack 20 has a large gap between them, the crack 20 can be filled with the crack repair materials 131 to 133 entirely. Therefore, the durability of the repaired portion of the crack 20 can be improved.

[0046] In the crack repair method, the cracks can be completely filled with the crack repair material, so that even if rust occurs in the internal reinforcing bars, water containing rust can be prevented from leaking out of the cracks, thereby preventing the surface of the reinforced concrete structure from becoming dirty due to rust.

[0047] The crack repair material composition and the crack repair method according to the embodiment of the present invention have been described above, but the present invention is not limited to the above embodiment and can be freely modified within the scope of the present invention. The structures containing metal reinforcement that are the subject of the crack repair method are not limited to reinforced concrete (RC) structures, but may also be reinforced steel-reinforced concrete (SRC) structures. In this case, reinforcing bars and steel frames are specific examples of metal reinforcement. The framework in which the metal reinforcement is embedded is not limited to concrete, but may be made of synthetic resin, ceramic, etc. The metal that constitutes the metal reinforcement is not particularly limited, and may be iron, copper, or alloys thereof, but is usually iron or its alloys.

[0048] In the crack repair method of the second embodiment, three types of crack repair materials are used, but the number of crack repair materials may be two, or any number of four or more. When the number of crack repair materials is two, a first crack repair material is injected into the crack, and then a second crack repair material having a higher viscosity than the first crack repair material is injected into the crack. When the number of crack repair materials is four, a first crack repair material is injected into the crack, then a second crack repair material having a higher viscosity than the first crack repair material is injected into the crack, then a third crack repair material having a higher viscosity than the second crack repair material is injected into the crack, and then a fourth crack repair material having a higher viscosity than the third crack repair material is injected into the crack. [Explanation of symbols]

[0049] 10...reinforced concrete structure (structure with metal reinforcement), 20...crack, 31...crack repair material, 131...first crack repair material, 132...second crack repair material, 133...third crack repair material.

Claims

1. A method for repairing cracks in a structure containing metal reinforcement, the method comprising the steps of: A step of preparing first and second crack repair material compositions containing an epoxy resin and a rust inhibitor and having different viscosities when prepared; Injecting the first crack repair material composition into the cracks of the structure from the surface of the structure toward the inside, and then injecting the second crack repair material composition; The first crack repair material composition has a lower viscosity than the second crack repair material composition; A repair method, wherein the content of the rust inhibitor in the first crack repair material composition is higher than the content of the rust inhibitor in the second crack repair material composition.

2. A method for manufacturing a repaired structure, comprising manufacturing a repaired structure by the repair method according to claim 1.

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