Reinforcement body and reinforcement method for concrete structures

Abstract

A reinforced concrete structure which is obtained by sequentially providing the surface of a concrete structure with at least a reinforcement layer and a protective layer. The reinforcement layer has a structure wherein a glass fiber sheet having a weight of from 500 to 1,000 g / m2 and a cured product of an adhesive for concrete structures are integrated with each other. The protective layer is a coating film of a protective coating material that contains an inorganic component. The difference between the refractive index of the glass fiber sheet and the refractive index of the cured product of an adhesive for concrete structures is less than 0.04.

Description

[Technical Field]

[0001] The present invention relates to a reinforcing body and a reinforcing method for concrete structures. More specifically, the present invention relates to a reinforcing body and a reinforcing method for concrete structures such as road tunnels. [Background technology]

[0002] Reinforcing concrete structures generally involves procedures such as removing deteriorated concrete, injecting crack reinforcement agents, and pouring lining concrete. However, since this often involves heavy work at heights, there is a need for simpler methods.

[0003] In response to this, a reinforcement method has been proposed that involves attaching synthetic fiber woven, knitted, or nonwoven fabrics to the reinforcement area and then applying and curing resin to form what is known as FRP (fiber-reinforced plastic). Conventionally, aramid fibers and carbon fibers have been used as synthetic fibers.

[0004] Furthermore, in recent years, it has become increasingly necessary to continuously monitor the changes in concrete structures over time after surface reinforcement has been carried out. However, the surface of concrete structures reinforced using conventional methods is covered with a reinforcing layer such as opaque resin or sheet material, making it difficult to visually observe the condition of the bare concrete structure from the outside.

[0005] Therefore, in concrete structures covered with a reinforcement layer using conventional reinforcement methods, it was necessary to remove a portion of the existing reinforcement layer applied to the surface and create an inspection window to expose the bare material when visually observing the condition of the base material from the outside.

[0006] However, there were concerns that creating inspection windows to observe the state of the concrete structure would reduce the strength of that area, and that the inspection windows could become the starting point for deterioration of the reinforcing layer.

[0007] Therefore, construction methods have been proposed that allow observation of the substrate of a concrete structure after construction using adhesives and fiber sheets. For example, Patent Document 1 proposes a method for repairing a concrete structure in which a primer resin (acrylic resin) is applied to the surface of the concrete structure, a fiber base material (nylon fiber or vinylon fiber) is attached to the applied surface, and a topcoat resin (acrylic resin) is applied on top of that. Patent Document 2 also proposes a method for reinforcing the surface of a concrete structure in which a transparent polyurethane resin solution is applied to the surface of the concrete structure, a continuous glass fiber sheet is attached, a transparent polyurethane resin solution is applied on top of that to impregnate the continuous glass fiber sheet, and then it is dried to solidify and form a transparent or translucent coating layer. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2006-342538 [Patent Document 2] Japanese Patent Publication No. 2010-1707 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, since the methods described in Patent Documents 1 and 2 are primarily aimed at suppressing concrete spalling, the layers formed by these methods do not possess the necessary strength to serve as reinforcing layers. In other words, the layers formed by these methods have low tensile strength, resulting in insufficient reinforcement performance for concrete structures, and also failing to adequately suppress the generation of harmful gases. [Means for solving the problem]

[0010] The present invention has been made to solve the above problems, and an object thereof is to provide a reinforcing member and a reinforcing method for a concrete structure that enable the base of the concrete structure to be visually recognized, and that are excellent in the reinforcing performance of the concrete structure and the effect of suppressing the generation of harmful gases.

[0011] As a result of intensive research, the inventor of the present invention has found that the above problems can be solved by sequentially providing a specific reinforcing layer and a specific protective layer on the surface of a concrete structure, and has thus completed the present invention.

[0012] That is, the present invention is a reinforcing member for a concrete structure in which at least a reinforcing layer and a protective layer are sequentially provided on the surface of the concrete structure, where the reinforcing layer has a structure in which a glass fiber sheet having a basis weight of 500 to 1000 g / m 2 is integrated with a cured product of an adhesive for a concrete structure, the protective layer is a coating film of a protective paint containing an inorganic component, the difference between the refractive index of the glass fiber sheet and the refractive index of the cured product of the adhesive for a concrete structure is less than 0.04, the glass fiber sheet is a biaxial woven fabric in which the fibers in the warp direction and the fibers in the weft direction are orthogonal, the law of nature , The protective coating contains an inorganic component with a melting point of 1000°C or lower and an organic binder in a solid content mass ratio of 30:70 to 70:30, and the inorganic component contains SiO 2 The content is 30% by mass or more. and is a reinforcing member for a concrete structure.

[0013] Further, the present invention is a reinforcing method for a concrete structure in which at least a reinforcing layer and a protective layer are sequentially formed on the surface of the concrete structure, where the reinforcing layer has a structure in which a glass fiber sheet having a basis weight of 500 to 一千 g / m 2 is integrated with a cured product of an adhesive for a concrete structure, the protective layer is a coating film of a protective paint containing an inorganic component, the difference between the refractive index of the glass fiber sheet and the refractive index of the cured product of the adhesive for a concrete structure is less than 0.04, The aforementioned glass fiber sheet is a biaxial woven fabric in which the warp fibers and weft fibers are perpendicular to each other. the law of nature , The protective coating contains an inorganic component with a melting point of 1000°C or lower and an organic binder in a solid content mass ratio of 30:70 to 70:30, and the inorganic component contains SiO 2 The content is 30% by mass or more. This is a method for reinforcing concrete structures. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a concrete reinforcement body and reinforcement method that allow the substrate of the concrete structure to be visually inspected, and that are excellent in terms of reinforcement performance of the concrete structure and the effect of suppressing the generation of harmful gases. [Modes for carrying out the invention]

[0015] Preferred embodiments of the present invention will be described below, but the present invention should not be construed as being limited thereto, and various modifications and improvements can be made based on the knowledge of those skilled in the art, without departing from the spirit of the invention. The multiple components disclosed in the embodiments can be combined in appropriate ways to form various inventions. For example, some components may be removed from all the components shown in the embodiments.

[0016] In the concrete structure reinforcement according to the embodiment of the present invention, at least a reinforcing layer and a protective layer are sequentially provided on the surface of the concrete structure. Furthermore, the concrete structure reinforcement method according to the embodiment of the present invention (hereinafter sometimes abbreviated as "reinforcing method") is carried out by sequentially forming at least a reinforcing layer and a protective layer on the surface of the concrete structure. Unless otherwise specified, "concrete" refers collectively to cement paste, mortar, and concrete.

[0017] The reinforcing layer, also known as the FRP layer, has a structure in which a glass fiber sheet and a hardened adhesive for concrete structures are integrated. The glass fiber sheets that make up the reinforcing layer can be obtained by forming glass fibers, known as glass yarn or glass roving, into woven fabrics, nonwoven fabrics, or braided fabrics. Since woven fabrics, nonwoven fabrics, and braided fabrics using glass fibers are commercially available, these commercially available products may also be used.

[0018] Furthermore, if the glass fiber sheet is a woven or braided fabric, its axial structure is not particularly limited and may be any of the various multiaxial structures, such as a biaxial or triaxial structure. Among these, the glass fiber sheet is preferably a biaxial woven fabric in which the warp and weft fibers are perpendicular to each other. By using a biaxial woven glass fiber sheet, it is possible to improve the visibility of the substrate while increasing the tensile strength of the glass fiber sheet and the reinforcing layer.

[0019] The basis weight of the glass fiber sheet is 500-1000 g / m². 2 Preferably 600-800 g / m² 2 The weight is 500g / m². 2 By doing so, the tensile strength of the reinforcing layer becomes 150 kN / m or more, thus obtaining the desired reinforcement performance. Furthermore, the basis weight is 1000 g / m². 2 By doing the following, the flexibility and workability of the reinforcement layer can be ensured.

[0020] The mesh size of the glass fiber sheet is not particularly limited, but is preferably 1 to 25 mm, more preferably 2 to 10 mm. By controlling the mesh size within the above range, the adhesion of the reinforcing layer to the concrete structure is improved, and the effect of suppressing the spread of fire in the event of a fire can be enhanced.

[0021] The glass fibers forming the glass fiber sheet preferably contain 12% by mass or more of ZrO2 and 10% by mass or more of R2O (where R is at least one selected from Li, Na, and K). By controlling the content of ZrO2 and R2O within the above range, the glass fiber sheet becomes less susceptible to deterioration by alkaline components derived from the concrete structure, thereby suppressing a decrease in the strength of the reinforcing layer.

[0022] The glass fiber sheet may contain components other than glass fibers. The components other than glass fibers are not particularly limited, and examples thereof include fibers made of components other than glass, thermoplastic resins, thermosetting resins, inorganic compounds, metals, and the like. These can be used alone or in combination of two or more.

[0023] The glass fiber sheet preferably contains heat-fusible fibers in at least one direction of the fibers. Here, the heat-fusible fiber means a fiber that melts by heat. By using heat-fusible fibers, the glass fibers can be adhered and the separation of the glass fiber sheet can be suppressed. Examples of heat-fusible fibers include nylon fibers, polyester fibers, and the like. These can be used alone or in combination of two or more.

[0024] The glass fiber sheet preferably has a content of components other than glass fibers of 50 g / m 2 or less, and more preferably less than 50 g / m 2 . By controlling the content of components other than glass fibers to 50 g / m 2 or less, the visibility of the base can be enhanced.

[0025] The adhesive for concrete structures used in the reinforcing layer integrates with the glass fiber sheet upon curing. The adhesive for concrete structures is not particularly limited, but is preferably a composition containing at least one resin selected from the group consisting of (meth)acrylic resins, vinyl ester resins, unsaturated polyester resins, urethane resins, urea resins, epoxy resins, and silicone resins, more preferably a composition containing at least one resin selected from the group consisting of (meth)acrylic resins, vinyl ester resins, unsaturated polyester resins, urethane resins, urea resins, epoxy resins, and silicone resins as a main component, and most preferably a composition containing at least one resin selected from the group consisting of (meth)acrylic resins and epoxy resins as a main component. By containing these resins, the tensile strength of the reinforcing layer can be improved. Herein, in this specification, "main component" means a component that accounts for 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more of the total.

[0026] A composition containing (meth)acrylic resin is preferably made to contain (meth)acrylate, a radical polymerization initiator, and a decomposition accelerator, as it cures at room temperature. Here, (meth)acrylic includes at least one selected from the group consisting of acrylic groups and methacrylic groups. (meth)acrylate includes at least one selected from the group consisting of acrylate and methacrylate. Among (meth)acrylates, it is preferable to include at least one selected from the group consisting of (meth)acrylates having aromatic groups and alkyl (meth)acrylates, as this greatly enhances the effects of the present invention. Among (meth)acrylates having aromatic groups, benzyl (meth)acrylate is preferred. Among alkyl (meth)acrylates, cyclohexyl (meth)acrylate is preferred.

[0027] Organic peroxides are preferred as radical polymerization initiators. Among organic peroxides, cumene hydroperoxide is preferred because it exhibits the greatest effect of the present invention. The amount of radical polymerization initiator used is preferably 0.5 to 10 parts by mass, and more preferably 1 to 7 parts by mass, per 100 parts by mass of (meth)acrylate. The decomposition accelerator is preferably one that reacts with the radical polymerization initiator at room temperature to generate radicals. A metal salt is preferred as the decomposition accelerator. Among metal salts, cobalt octylate is preferred because it exhibits the greatest effect of the present invention. The amount of decomposition accelerator used is preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 4 parts by mass, per 100 parts by mass of (meth)acrylate.

[0028] For compositions containing epoxy resin, in terms of curing properties, at least the main component (component A) and at least the curing agent (component B) are stored separately. In this case, both components can be used by applying them to the substrate simultaneously or separately, allowing them to come into contact and cure. Aromatic epoxy resins are preferred as the epoxy resin. Among aromatic epoxy resins, compounds having a bisphenol structure are preferred. Bisphenol A type diglycidyl ether is preferred as the compound having a bisphenol structure. A curing agent is a component that can cure epoxy resin. Amine compounds are preferred as curing agents. The amount of curing agent used is preferably 0.5 to 1.5 equivalents of active hydrogen in the curing agent, and more preferably 0.8 to 1.3 equivalents, per equivalent of epoxy groups in the epoxy resin. The amount of curing agent used is preferably 30 to 100 parts by mass, and more preferably 50 to 70 parts by mass, per 100 parts by mass of epoxy resin.

[0029] The adhesive (composition) for concrete structures may further contain inorganic components as needed. Preferably, the inorganic components include oxides of metallic elements (main group elements, transition elements). Among the oxides of metallic elements (main group elements, transition elements), titanium oxide is preferred. The amount of inorganic components used is preferably 0.5 to 10 parts by mass, and more preferably 1 to 7 parts by mass, per 100 parts by mass of resin.

[0030] Adhesives for concrete structures may further contain known components such as oil, rubber, viscosity modifiers, pigments, dyes, plasticizers, sensitizers, catalysts, polymerization inhibitors, waxes, tackifiers, silane coupling agents, antioxidants, flame retardants, and organic solvents, to the extent that they do not impair the performance of the adhesive.

[0031] The curing method for adhesives for concrete structures is not particularly limited, and various known curing methods can be used. For example, methods such as curing by volatilizing volatile components, curing by reacting the components of the adhesive with moisture in the air, curing by mixing two (or more) components, a main agent and a hardener, and curing by a chemical reaction, and curing by applying external energy such as heat or light can be used. Among these, considering the strength of the reinforcing layer and the workability for concrete structures, the method of mixing two components and curing by a chemical reaction is preferred.

[0032] Two or more types of adhesives for concrete structures may be used in combination. When using two or more types of adhesives for concrete structures in combination, the two or more adhesives may be mixed in advance before use, or the first type of adhesive for concrete structures may be applied first, and then the second and subsequent types of adhesives may be applied.

[0033] The cured product of the adhesive for concrete structures preferably has a Gardner color count of 8 or less. By controlling the Gardner color count to 8 or less, the visibility of the substrate can be improved. The Gardner color count can be measured in accordance with JIS K 0071-2:1998.

[0034] The difference in refractive index between the glass fiber sheet and the cured adhesive for concrete structures that constitute the reinforcing layer is less than 0.04, preferably 0.025 or less, and more preferably less than 0.025. By controlling the difference in refractive index within this range, visibility of the substrate can be ensured. Herein, in this specification, "refractive index" means the refractive index measured in accordance with JIS K7142:2014.

[0035] The tensile strength per unit length of a Type B test specimen, prepared in accordance with JIS A1191:2004 using a glass fiber sheet and concrete structure adhesive used in the reinforcing layer, is preferably 150 kN / m or more, and more preferably 175 kN / m or more. Here, a Type B test specimen refers to a glass fiber sheet impregnated with concrete structure adhesive. With a tensile strength within this range, it is possible to achieve reinforcing performance comparable to conventional concrete structure reinforcement methods using carbon fiber sheets or aramid fiber sheets.

[0036] The reinforcing layer is formed using the above-mentioned glass fiber sheet and concrete structure adhesive. Specifically, the reinforcing layer is formed by impregnating the glass fiber sheet with concrete structure adhesive and then curing the concrete structure adhesive. When forming a reinforcing layer on the surface of a concrete structure, a concrete adhesive is applied to the surface of the concrete structure, a glass fiber sheet is placed on the applied surface, and then the glass fiber sheet is impregnated with the concrete adhesive and allowed to harden.

[0037] For applying adhesives to concrete structures, known methods such as application with rollers, trowels, spatulas, and spray painting can be used. The adhesive for concrete structures may be applied all at once or in two or more stages, but it is preferable to apply it in two or more stages. Applying the adhesive in two or more stages prevents dripping and allows for the application of the amount necessary for integration with the glass fiber sheet. When applying the adhesive in two or more stages, the glass fiber sheet should be placed first, and then the adhesive should be applied on top of it.

[0038] The amount of adhesive for concrete structures to be applied is preferably 0.2 to 2.0 kg / m² per glass fiber sheet. 2 More preferably 0.5 to 1.4 kg / m 2 The amount of adhesive to be applied to concrete structures is 0.2 kg / m².2 By controlling the process as described above, the fiberglass sheet can be fixed in place. Furthermore, the application amount of adhesive for concrete structures is 2.0 kg / m². 2 By controlling the following, the visibility of the substrate can be improved.

[0039] There are no particular limitations on the method for impregnating the glass fiber sheet with adhesive for concrete structures, but it is preferable to use a de-aerating roller. By using a de-aerating roller, air bubbles in the adhesive for concrete structures and within the glass fiber sheet are removed, making it easier to impregnate the glass fiber sheet with the adhesive for concrete structures.

[0040] The reinforcing layer preferably includes two or more glass fiber sheets, and more preferably two glass fiber sheets. By using two or more glass fiber sheets, it is possible to achieve reinforcing performance equivalent to that of existing reinforcing methods using carbon fiber sheets or aramid fiber sheets. When using two or more glass fiber sheets, the glass fiber sheets may be placed on the surface coated with the adhesive for concrete structures at one time, or they may be placed one by one in two or more stages, but it is preferable to place them one by one in two or more stages. Placing the glass fiber sheets one by one in two or more stages helps to prevent them from falling due to their own weight. When placing the glass fiber sheets one by one in two or more stages, the process can be repeated by placing a glass fiber sheet on the surface coated with the adhesive for concrete structures, then applying more adhesive on top of it, and then placing another glass fiber sheet on that coated surface.

[0041] The reinforcing layer may be fitted with measures to prevent the fiberglass sheet from falling, using known technologies such as anchor pins and anchor bolts, as needed. There are no particular limitations on the number of anchor pins and anchor bolts used, but the area of ​​the reinforcing layer covered by anchor pins and anchor bolts is preferably 20% or less of the entire reinforcing layer, more preferably less than 20%, even more preferably 10% or less, and most preferably less than 10%. By controlling the area covered by the reinforcing layer within the above range, visibility of the substrate can be ensured.

[0042] Before forming the reinforcing layer on the surface of the concrete structure, the concrete structure may be prepped as needed. Prepping the concrete structure ensures that the adhesion of the reinforcing layer to the concrete structure is maintained over a long period of time. Surface preparation is performed to remove laitance, surface dirt, and deteriorated substrate, and known techniques such as water jet treatment, sandblasting, sanding, and wire brushing can be used.

[0043] Furthermore, before forming the reinforcing layer on the surface of the concrete structure, cross-sectional repair of the concrete structure may be performed as needed. By performing cross-sectional repair, the adhesion of the reinforcing layer to the concrete structure can be improved. As cross-section repair materials, known materials such as concrete, mortar, cement paste, grout, polymer cement mortar, and resin mortar can be used. These materials can be used individually or in combination of two or more.

[0044] Furthermore, a primer may be applied to the surface of the concrete structure before forming the reinforcing layer, if necessary. Applying a primer not only improves the adhesion between the concrete structure and the reinforcing layer, but also allows the primer to impregnate cracks and other deteriorated parts of the concrete structure, restoring its soundness. In addition, the primer inhibits the seepage of moisture, alkali metals, and gases from the concrete structure, thus maintaining the performance of the reinforcing layer over the long term.

[0045] As primers, known materials such as (meth)acrylic resin primers, epoxy resin primers, vinyl ester resin primers, silicone resin primers, and inorganic primers can be used. These materials can be used individually or in combination of two or more. The primer preferably has a number of guardner colors of 8 or less in its cured form. By controlling the number of guardner colors to 8 or less, the visibility of the substrate can be improved. The amount of primer to apply varies depending on the condition of the concrete structure, but generally it is 0.05 to 1.0 kg / m². 2 That is the case. The method of applying the primer is not particularly limited, and known methods such as application with a roller, brush, trowel, spatula, or spray painting can be used.

[0046] Furthermore, before forming the reinforcing layer on the surface of the concrete structure, the unevenness of the structure may be adjusted in advance as needed. By adjusting the unevenness, the reinforcing layer can be formed uniformly on the surface of the concrete structure, thereby stably exhibiting reinforcing performance over a large area. For leveling uneven surfaces, leveling materials can be used. Known materials such as resin mortar or polymer cement mortar, which combine resin and aggregate, can be used as leveling materials. These materials can be used individually or in combination of two or more. The surface leveling material is preferably such that the number of Gardner colors in its cured form is 8 or less. By controlling the number of Gardner colors to 8 or less, the visibility of the substrate can be improved. The amount of surface leveling agent to apply varies depending on the surface's unevenness, but generally, it is 1.8 kg / m². 2 The following is preferable: 1.8 kg / m 2 Less than is preferable. As for the application method of the leveling material, known methods such as application with a trowel or spatula, or spray painting can be used.

[0047] The protective layer is a protective coating film formed on the surface of the reinforcing layer. Here, in this specification, "coating film" means the cured product of the protective coating. The protective coating that forms the protective layer contains inorganic components with a melting point of 1000°C or lower. By including such inorganic components in the protective coating, the inorganic components melt in the event of a fire and form a glassy coating, thereby suppressing the spread of fire and the generation of harmful gases. The lower limit of the melting point of the inorganic components is not particularly limited, but is generally 400°C. Herein, in this specification, "melting point" means the melting point measured by a differential scanning calorimetry (DSC).

[0048] Inorganic components with a melting point of 1000°C or less include SiO2-containing components such as silicon dioxide, silicic acid, silicates, and silica; metallic elements (mainstream elements, transition elements), nonmetallic elements, and their hydrogen compounds, oxides, oxoates, hydroxides, halides, sulfates, nitrates, carbonates, and acetates; and metal complexes (coordination compounds). These can be used individually or in combination of two or more. Examples of silicates include aluminosilicate, ultramarine, Egyptian blue, yttrium rowanite, aluminum silicate, potassium silicate, calcium silicate, sodium silicate, hafnium(IV) silicate, magnesium silicate, elestadite, tobe mica, sodium hexafluorosilicate, and bentonite.

[0049] The protective coating can further contain an organic binder. By including an organic binder in the protective coating, the binding strength of the inorganic components is enhanced, allowing for the stable formation of the coating film. Examples of organic binders include waxes, polyvinyl alcohol, paraffin, polyvinyl butyral, (meth)acrylic resins, urethane resins, glyoxal resins, phenolic resins, butadiene resins, polycarboxylic acids, fatty acids, fatty acid amides, and polyesters. These can be used individually or in combination of two or more.

[0050] The solid content mass ratio of inorganic components with a melting point of 1000°C or lower to organic binders is preferably 30:70 to 70:30. By controlling the solid content mass ratio within this range, it is possible to stably achieve both film-forming properties and the effects of the protective layer (effects of suppressing the spread of fire and the generation of harmful gases in the event of a fire).

[0051] The inorganic component preferably contains 30% by mass or more of SiO2. By controlling the SiO2 content within this range, the above-mentioned effects of the protective layer can be stably improved.

[0052] Protective coatings may contain known components such as inorganic fillers, oils, rubbers, viscosity modifiers, pigments, dyes, plasticizers, polymerization initiators, sensitizers, catalysts, polymerization inhibitors, waxes, tackifiers, silane coupling agents, antioxidants, flame retardants, and organic solvents, to the extent that they do not degrade their performance.

[0053] The protective layer (coating) is formed by applying a protective coating to the surface of the reinforcing layer and then allowing it to harden. The curing method for protective coatings is not particularly limited, and various known methods can be used. For example, methods such as curing by volatilizing the volatile components of the protective coating, curing by reacting the components of the protective coating with moisture in the air, curing by a chemical reaction after mixing two (or more) components, a main agent and a hardener, or curing by applying external energy such as heat or light can be used. Among these, considering compatibility with inorganic components and ease of application, the method of curing by volatilizing the volatile components (moisture) of the protective coating is preferred.

[0054] The protective coating can be applied using known methods such as rollers, brushes, trowels, spatulas, or spray painting. The amount of protective coating to be applied is preferably 0.01 to 1.0 kg / m² in terms of solid content. 2 , more preferably 0.02~0.2 kg / m 2 That is the case.

[0055] The protective layer (coating) preferably has 8 or fewer guardner colors. By controlling the number of guardner colors to 8 or fewer, the visibility of the substrate can be improved.

[0056] In the concrete structure reinforcement body and reinforcement method according to the embodiment of the present invention, a coating, adhesive layer, fiber sheet, film, resin molded product, etc., known in the art, may be provided individually or in combination between the reinforcement layer and the protective layer or on the surface of the protective layer, as necessary.

[0057] In the concrete structure reinforcement according to the embodiment of the present invention, when subjected to a gas toxicity test (using multiple mice) as stipulated in the Fire Resistance Performance Testing and Evaluation Procedure Manual based on the Building Standards Act of Japan, it is preferable that the average time from the start of the test until the mice cease their activity is 6.8 minutes or more. With such an average time, the possibility of evacuees being caught in harmful combustion gases and having their lives endangered in the event of a tunnel fire is reduced. Therefore, the concrete structure reinforcement according to the embodiment of the present invention can be used inside tunnels.

[0058] In the concrete structure reinforcement according to the embodiment of the present invention, it is preferable that the flame extinction time in the fire spread test according to NEXCO Test Method 738 is 30 seconds or less, and the leading edge of the fire caused by combustion is less than 600 mm from the ignition point. With such a flame extinction time, the possibility of evacuees being caught in harmful combustion gases and endangering their lives in the event of a tunnel fire is reduced. Therefore, the concrete structure reinforcement according to the embodiment of the present invention can be used inside tunnels. Herein, in this specification, "fire spread test in NEXCO Test Method 738" means NEXCO Test Method 738-2011, "Method for testing the fire spread of tunnel repair materials." [Examples]

[0059] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. Note that Example 19 is shown below. 、 20 and 27-30 This is an example.

[0060] <Preparation of glass fiber sheets> The raw materials with the composition shown in Table 1 were melted and spun into yarn to obtain glass fibers (glass yarn).

[0061] [Table 1]

[0062] Next, a beam (fiber bundle) was obtained by bundling a predetermined number of glass yarns and heat-fusible threads formed from nylon fibers (heat-fusible fibers) with a sizing agent. An emulsion containing a silane coupling agent was used as the sizing agent. Glass fiber sheets of each axial structure were obtained using the obtained beam. Details of the fabricated glass fiber sheets are shown in Table 2. In the beam configuration, "other" refers to the sizing agent.

[0063] [Table 2]

[0064] <Adhesive for concrete structures> Adhesives for concrete structures were prepared by mixing the components shown in Table 3. The Gardner color number and refractive index of the cured adhesives were also measured. The results are shown in Table 3. The Gardner color number and refractive index were measured according to the method described above.

[0065] [Table 3]

[0066] The components shown in Table 3 are as follows: (Acrylic resin composition A) This is an acrylic resin composition that hardens by redox polymerization, containing Viscoat #160 (trade name, manufactured by Osaka Organic Chemical Co., Ltd., benzyl acrylate), Perkmill H (trade name, manufactured by NOF Corporation, cumene hydroperoxide), and cobalt octoate (manufactured by Osaki Industries Co., Ltd.) in a mass ratio of 100:2:2. (Acrylic resin composition B) This is an acrylic resin composition that hardens by redox polymerization, containing Viscoat #155 (trade name, manufactured by Osaka Organic Chemical Co., Ltd., cyclohexyl acrylate), Perkmill H (trade name, manufactured by NOF Corporation, cumene hydroperoxide), and cobalt octoate (manufactured by Osaki Industries Co., Ltd.) in a mass ratio of 100:2:2. (Epoxy resin composition) This epoxy resin composition contains jER828 (trade name, manufactured by Mitsubishi Chemical Corporation, bisphenol A type diglycidyl ether) and ST11 (trade name, manufactured by Mitsubishi Chemical Corporation, modified amine) in a mass ratio of 100:60, and cures by a polyaddition reaction between a glycidyl group and an amino group.

[0067] (Vinyl acetate resin composition) CH18 (product name, manufactured by Konishi Co., Ltd., vinyl acetate resin emulsion type adhesive) is a one-component curing adhesive that hardens through the evaporation of water. (Water glass) This is No. 3 water glass (manufactured by Fuji Chemical Co., Ltd.) as specified in JIS K1408, which hardens through the evaporation of water. (Titanium dioxide) The product is R820 (product name, manufactured by Ishihara Sangyo Co., Ltd., titanium dioxide produced by the sulfuric acid method). Titanium dioxide was used to adjust the range of colors for adhesives used in concrete structures.

[0068] <Protective paint> A protective coating with the composition shown in Table 4 was prepared using Snowtex 40 (trade name, manufactured by Nissan Chemical Industries, Ltd., colloidal silica) as the SiO2-containing component, TTO-W-5 (trade name, manufactured by Ishihara Sangyo Co., Ltd., neutral titania sol) as the other inorganic component, and R967 (trade name, manufactured by Kusumoto Kasei Kogyo Co., Ltd., water-based polyurethane resin) as the organic binder. The Gardner color number of the prepared protective coating film (cured product) was measured according to the method described above. In addition, the melting points of the inorganic components were measured using a differential scanning calorimeter (Brucker DSC3100SA). The results are also shown in Table 4.

[0069] [Table 4]

[0070] The following evaluations were performed using the glass fiber sheets, concrete structure adhesives, and protective coatings obtained above. Table 5 shows the combinations of materials used in each example and comparative example. In Table 5, the difference in refractive index refers to the difference between the refractive index of the glass fiber sheet and the refractive index of the cured concrete structure adhesive.

[0071] [Table 5]

[0072] (1) Visibility A 150mm x 70mm x 10mm mortar piece, prepared in accordance with JIS R5201:2015, had its application surface (150mm x 70mm) sanded with #150 grit sandpaper to remove laitance, and dust was removed with compressed air. Two crack patterns, 0.2mm and 0.5mm wide, were drawn along the longitudinal direction of the application surface using black and HB pencils to obtain a test piece (hereinafter referred to as "mortar piece for visibility evaluation"). Next, Denka's acrylic crack injection repair material (Denka DK550-003R) was applied as a primer to the surface of the mortar sample used for visibility evaluation using a roller. The amount of primer applied was 0.15 kg / m². 2 That's what I decided. After applying the primer, it was left for 15 minutes to form a reinforcing layer on top of the primer. The reinforcing layer was formed as follows: Concrete structure adhesive was applied as a base coat using a rubber spatula or trowel (application amount: 0.6 kg / m²). 2 The following steps were taken: A predetermined number of glass fiber sheets were placed on the coated surface immediately after application, and the primer resin was impregnated into the glass fiber sheets using a de-aeration roller. Concrete structure adhesive was used as the primer resin. Next, concrete structure adhesive was applied as the topcoat using a rubber spatula or trowel (application amount: 0.6 kg / m²). 2 After that, the concrete structure adhesive was cured at 20°C for 24 hours to harden and form a reinforcing layer.

[0073] Next, a protective layer was formed on the surface of the reinforcing layer. The protective layer was formed by applying a protective coating to the surface of the reinforcing layer with a roller (coating amount: 0.15 kg / m²). 2 After that, the protective coating was dried and hardened at 20°C for 7 days to form a protective layer. Visibility was evaluated by visually observing the crack pattern after the formation of the reinforcement layer, according to the following criteria. ○: Cracks measuring 0.2 mm and 0.5 mm in width are visible throughout the entire area. △: Cracks with a width of 0.5 mm are visible throughout the entire area, but some or all of the cracks with a width of 0.2 mm are not visible. ×: Part or all of the crack patterns, both 0.2 mm wide and 0.5 mm wide, are not visible to the naked eye.

[0074] (2) Alkali resistance A test specimen was obtained by preparing a 150mm x 70mm x 10mm mortar piece in accordance with JIS R5201:2015, then sanding the application surface (150mm x 70mm surface) with #150 grit sandpaper to remove laitance, and removing dust with compressed air (hereinafter referred to as "mortar piece for alkali resistance evaluation"). Next, a primer was applied to the application surface of the mortar sample used for alkali resistance evaluation under the same conditions as for the visibility evaluation. Then, a reinforcing layer was formed on top of the primer using a concrete structure adhesive and a glass fiber sheet, and a protective layer was formed using a protective coating. The reinforcing layer and the protective layer were formed sequentially. Alkali resistance was measured as follows: After the protective layer was formed, mortar samples for alkali resistance evaluation were immersed in a saturated calcium hydroxide solution for 28 days. After immersion, the mortar samples were removed from the solution. The surface condition was immediately observed visually and evaluated according to the following criteria. ○: No discoloration, cracks, peeling, blistering, fissures, or leakage are observed on the surface. △: Discoloration, cracking, peeling, blistering, fissures, or leakage are observed on the surface.

[0075] (3) Workability A test specimen was obtained by sanding the 300mm x 300mm surface of a 300mm x 300mm x 60mm ordinary concrete slab (designation: N300), manufactured in accordance with JIS A5371:2016, with #150 grit sandpaper to remove laitance, and then removing dust with an air blower (hereinafter referred to as "concrete slab"). Next, the 300mm x 60mm surface of the concrete slab was brought into contact with the ground, and the construction surface was positioned perpendicular to the ground. Then, under the same conditions as for the visibility evaluation, a primer was applied, and a reinforcing layer was formed on top of it using concrete structure adhesive and glass fiber sheeting. During the reinforcement layer formation process, the state of the concrete structure adhesive until hardening was completed was visually observed and evaluated according to the following criteria. ○: There is no peeling, sliding, or falling of the fiberglass sheet, and no sagging of the adhesive for concrete structures occurs. △: Minor slippage of the fiberglass sheet and sagging of the adhesive used for concrete structures were observed. ×: Peeling, falling, or significant sliding of the fiberglass sheet, and sagging of the adhesive for concrete structures were observed.

[0076] (4) Concrete adhesion In the evaluation of workability, a concrete slab with a reinforced layer was used, and a protective layer was formed on the surface of the reinforced layer under the same conditions as in the evaluation of visibility. Next, a 40mm x 40mm steel jig was attached to the surface of the protective layer with Denka's acrylic resin mortar (Denka Dyna N), and cuts were made along the jig until they reached the concrete slab. After that, the jig was pulled perpendicular to the attachment surface using a Building Research Institute type tensile adhesion tester to determine the adhesion strength (N / mm²). 2 The following parameters were measured. The measurement results were evaluated according to the following criteria. ○: 2.0 N / mm 2 The above (Conformity standards for surface protection method (medium corrosion protection type C) in the repair guidelines of Hanshin Expressway Co., Ltd.) △: 1.5 N / mm 2 Above (NEXCO bridge structure flaking prevention method conformity standards) ×: 1.5N / mm 2 less than

[0077] (5) FRP tensile strength Using the fiberglass sheets and concrete structure adhesive used to prepare the reinforcing layer, a Type B test specimen (FRP) was prepared in accordance with JIS A1191:2004, and its maximum tensile load (kN) was calculated. Next, the FRP tensile strength per unit length was calculated according to the following formula [1]. f A =F÷A×B ··· [1] f A : Tensile strength of the test specimen per unit length (kN / m) F: Maximum tensile load of the test specimen (kN) A: Number of fiber bundles in the test specimen (fibers) B: Number of fiber bundles arranged in the tensile direction per meter of glass fiber sheet width (fibers / meter)

[0078] (6) Tensile strength of the reinforcing layer Using the FRP tensile strength per unit length (kN / m) obtained above, the tensile strength of the reinforcement layer was calculated according to the following formula [2]. f B =f A ×C ··· [2] f B :Tensile strength of the reinforcing layer (kN / m) f A : Tensile strength of the test specimen per unit length (kN / m) C: Number of glass fiber sheets (sheets) The tensile strength of the reinforcement layer was evaluated according to the following criteria. 〇:350kN / m or more △: 300kN / m or more and less than 350kN / m ×: Less than 300kN / m

[0079] (7) Gas toxicity Test specimens were obtained by removing dust from the surface (220mm x 220mm side) of a 220mm x 220mm x 10mm calcium silicate board, manufactured in accordance with JIS A5430:2013, using an air blower. Next, a primer was applied to the surface of the test specimen under the same conditions as for the visibility evaluation. Then, a reinforcing layer was formed using a concrete structure adhesive and a glass fiber sheet, followed by a protective layer using a protective coating. The reinforcing layer and protective layer were formed sequentially. The gas toxicity test was conducted using mice as defined in the Fire Resistance Performance Testing and Evaluation Procedure Manual based on Japan's Building Standards Act. The average inactivity time (Xs) of the mice was calculated and evaluated according to the following criteria. For example, the above Fire Resistance Performance Testing and Evaluation Procedure Manual is published by the Better Living Foundation. ○: Xs for 7.2 minutes or more △: Xs is between 6.8 minutes and less than 7.2 minutes ×: Xs takes less than 6.8 minutes

[0080] (8) Flammability Test specimens were obtained by removing dust from the surface of a 900mm x 600mm x 12mm calcium silicate board, manufactured in accordance with JIS A5430:2013, using an air blower. Next, a primer was applied to the surface of the test specimen under the same conditions as for the visibility evaluation. Then, a reinforcing layer was formed using a concrete structure adhesive and a glass fiber sheet, followed by a protective layer using a protective coating. The reinforcing layer and protective layer were formed sequentially. The fire spreadability was evaluated according to the following criteria by measuring the extinction time and the ignition point at the tip of the fire caused by combustion in the fire spreadability test specified in NEXCO Test Method 738. ○: The flame extinguishing time is 10 seconds or less, and the tip of the fire caused by combustion is less than 500 mm from the ignition point. △: The flame extinguishing time is 30 seconds or less, and the tip of the fire caused by combustion is less than 600 mm from the ignition point. ×: The flame extinguishing time exceeds 30 seconds, or the tip of the fire caused by combustion is 600 mm or more from the ignition point. The results of each of the above evaluations are shown in Table 6.

[0081] [Table 6]

[0082] As shown in Table 6, all evaluations were favorable for the reinforcement methods of Examples 1 to 31, which formed specific reinforcing layers and specific protective layers. In contrast, in the reinforcement method of Comparative Example 1, the basis weight of the glass fiber sheet used to form the reinforcement layer was too low, resulting in insufficient tensile strength of the reinforcement layer. In the reinforcement method of Comparative Example 2, the basis weight of the glass fiber sheet used to form the reinforcement layer was too high, resulting in insufficient workability of the reinforcement layer. In the reinforcement methods of Comparative Examples 3 to 6, the difference between the refractive index of the glass fiber sheet and the refractive index of the cured concrete structure adhesive was too large, resulting in insufficient visibility. In the reinforcement method of Comparative Example 7, the protective coating did not contain inorganic components, resulting in insufficient gas toxicity and fire spread. In the reinforcement method of Comparative Example 8, a protective layer was not formed, resulting in insufficient gas toxicity and fire spread. In the reinforcement method of Comparative Example 9, glass fiber sheets were not used, resulting in insufficient tensile strength, gas toxicity, and fire spread of the reinforced layer. In the reinforcement method of Comparative Example 10, since an adhesive for concrete structures was not used, it was not possible to form the reinforcement layer (FRP) itself, and therefore, each evaluation could not be performed.

[0083] As can be seen from the above results, the present invention provides a concrete reinforcement body and reinforcement method that allows the substrate of the concrete structure to be visually inspected, and that are excellent in reinforcing performance of the concrete structure and in suppressing the spread of fire and the generation of harmful gases in the event of a fire.

Claims

1. A concrete reinforcement body having at least a reinforcing layer and a protective layer sequentially provided on the surface of the concrete structure, The aforementioned reinforcing layer has a basis weight of 500 to 1000 g / m². 2 It has a structure in which a glass fiber sheet and a cured product of an adhesive for concrete structures are integrated. The protective layer is a protective coating film containing inorganic components. The difference between the refractive index of the glass fiber sheet and the refractive index of the cured product of the adhesive for concrete structures is less than 0.

04. The aforementioned glass fiber sheet is a biaxial woven fabric in which the warp fibers and weft fibers are perpendicular to each other. The protective coating is a reinforcing body for concrete structures, comprising an inorganic component with a melting point of 1000°C or less and an organic binder in a solid content mass ratio of 30:70 to 70:30, and having a SiO2 content of 30% by mass or more in the inorganic component.

2. The glass fibers forming the glass fiber sheet contain 12% by mass or more of ZrO 2 , and 10% by mass or more of R 2 A reinforcing body for a concrete structure according to claim 1, comprising O (where R is at least one selected from Li, Na, and K).

3. The glass fiber sheet has a mesh opening of 1 to 25 mm, the reinforcing body for a concrete structure according to claim 1 or 2.

4. The glass fiber sheet comprises heat-fused fibers in at least one direction, as described in any one of claims 1 to 3, for the reinforcing body of a concrete structure.

5. The aforementioned glass fiber sheet contains 50 g / m² of components other than glass fibers. 2 A reinforcing body for a concrete structure according to any one of claims 1 to 4, which is less than [amount missing].

6. The concrete structure reinforcing body according to any one of claims 1 to 5, wherein the adhesive for concrete structures is a composition comprising at least one resin selected from the group consisting of (meth)acrylic resin, vinyl ester resin, unsaturated polyester resin, urethane resin, urea resin, epoxy resin, and silicone resin.

7. The concrete structure reinforcing body according to any one of claims 1 to 6, wherein the cured product of the adhesive for concrete structures has a Gardner color number of 8 or less.

8. The reinforcing layer comprises two or more glass fiber sheets, the reinforcing body for a concrete structure according to any one of claims 1 to 7.

9. The reinforcing body for a concrete structure according to any one of claims 1 to 8, wherein the protective layer has a Gardner color number of 8 or less.

10. A concrete structure reinforcing body according to any one of claims 1 to 9, wherein a Type B test specimen prepared in accordance with JIS A1191:2004 using the glass fiber sheet and the adhesive for concrete structures has a tensile strength of 150 kN / m or more per unit length.

11. A concrete reinforcement body according to any one of claims 1 to 10, wherein, in a gas toxicity test stipulated in the Fire Resistance Performance Testing and Evaluation Procedure Manual based on the Building Standards Act of Japan, the average time from the start of the test until the mouse stops moving is 6.8 minutes or more.

12. A concrete reinforcement according to any one of claims 1 to 11, wherein, in the fire spread test according to NEXCO Test Method 738, the flame extinction time is 30 seconds or less, and the leading edge of the fire caused by combustion is less than 600 mm from the ignition point.

13. A method for reinforcing a concrete structure, comprising sequentially forming at least a reinforcing layer and a protective layer on the surface of the concrete structure, The aforementioned reinforcing layer has a basis weight of 500 to 1000 g / m². 2 It has a structure in which a glass fiber sheet and a cured product of an adhesive for concrete structures are integrated. The protective layer is a protective coating film containing inorganic components. The difference between the refractive index of the glass fiber sheet and the refractive index of the cured product of the adhesive for concrete structures is less than 0.

04. The aforementioned glass fiber sheet is a biaxial woven fabric in which the warp fibers and weft fibers are perpendicular to each other. A method for reinforcing concrete structures, wherein the protective coating contains an inorganic component with a melting point of 1000°C or less and an organic binder in a solid content mass ratio of 30:70 to 70:30, and the SiO2 content in the inorganic component is 30% by mass or more.

14. The method for reinforcing a concrete structure according to claim 13, wherein the reinforcing layer is formed by applying the adhesive for concrete structures to the surface of the concrete structure, placing the glass fiber sheet on the applied surface, and then impregnating the glass fiber sheet with the adhesive for concrete structures and allowing it to harden.

15. The aforementioned glass fiber sheet contains 50 g / m² of components other than glass fibers. 2 A method for reinforcing a concrete structure according to claim 13 or 14, wherein the amount is less than [amount missing].

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