Reinforcing or repairing method for structure

Abstract

To provide a reinforcing or repairing method for structure that can improve the workability of reinforcing or repairing construction work.SOLUTION: A repairing method includes: a temporary fixing step of bringing a reinforcing fiber sheet 10, having been already coated with an adhesion layer 20 made of thermoplastic resin, on the adhesion layer 20 side into contact with a structure 1, and temporarily fixing the reinforcing fiber sheet 10 to the structure 1; a sealing step of covering the reinforcing fiber sheet 10 with a sealing seat 30 and also sealing the sealing sheet 30; an impregnating step of fusing and polymerizing the adhesion layer 20 through heating, and producing a vacuum inside the sealing sheet through evacuation to impregnate gaps etc., of the reinforcing fiber sheet 10 with the adhesion layer 20; a primary fixing step of cooling and hardening the adhesion layer 20; and a peeling step of peeling the sealing sheet 30 from the reinforcing fiber sheet 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for reinforcing or repairing structures such as concrete structures and wooden structures. [Background technology]

[0002] As a conventional method for reinforcing or repairing a structure, Patent Document 1 describes a method in which a reinforcing fiber sheet and a thermoplastic epoxy resin are overlapped and brought into contact with the structure, these fiber sheets etc. are sealed with a sealing sheet, the thermoplastic epoxy resin is then heated to melt, the space within the sealing sheet is evacuated to a vacuum, the thermoplastic epoxy resin is impregnated into the gaps in the reinforcing sheet and the voids in the structure, and the thermoplastic epoxy resin is then cooled and solidified. The thermoplastic epoxy resin is also arranged on the structure by, for example, a thermal spraying method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-69432 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned method, a thermoplastic epoxy resin is basically applied to a structure by a thermal spraying method or the like, and then a replacement fiber sheet is placed on the structure. However, in this case, the reinforcement or repair work requires a lot of man-hours, so there is a need for an improvement in workability.

[0005] Therefore, an object of the present invention is to provide a method for reinforcing or repairing a structure, which can improve the workability of the reinforcement or repair construction work. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention is a method for reinforcing or repairing a structure by adhering a reinforcing fiber sheet to the structure, the method comprising: a coating step of coating at least one surface of the reinforcing fiber sheet with a raw material of a thermoplastic resin containing an unpolymerized portion to form an adhesive layer; a temporary fixing step of contacting the adhesive layer side of the reinforcing fiber sheet with the structure and temporarily fixing the reinforcing fiber sheet to the structure; a sealing step of covering at least a portion of the peripheral edge of the reinforcing fiber sheet on the structure with at least a sealing sheet and sealing the sealing sheet; and a method of reinforcing or repairing the adhesive layer by adhering a reinforcing fiber sheet to the structure. The method includes a heating and impregnation process in which the raw material of the thermoplastic resin is heated to melt and polymerize it, the internal space defined by the sealing sheet and the structure is evacuated to a vacuum, the sealing sheet is used to press the reinforcing fiber sheet against the structure, and the thermoplastic resin is impregnated into the gaps in the reinforcing fiber sheet and the voids or gaps present on the surface of the structure; a final fixing process in which the thermoplastic resin is cooled and hardened, and the reinforcing fiber sheet is finally fixed to the structure via the adhesive layer; and a peeling process in which the sealing sheet is peeled off from the reinforcing fiber sheet.

[0007] Another aspect of the present invention is a method for reinforcing or repairing a structure by adhering a reinforcing fiber sheet to the structure, the method comprising: a raw material impregnation step of pre-impregnating the reinforcing fiber sheet with a raw material of a thermoplastic resin containing an unpolymerized portion into the reinforcing fiber sheet; a temporary fixing step of contacting the reinforcing fiber sheet with the structure and temporarily fixing the reinforcing fiber sheet to the structure; a sealing step of covering at least a portion of the peripheral edge of the reinforcing fiber sheet on the structure with at least a sealing sheet and sealing the sealing sheet; and a step of heat-treating the raw material of the thermoplastic resin to form a thermoplastic resin. The method includes a heating and impregnation process in which the thermoplastic resin is melted and polymerized, while evacuating the internal space defined by the sealing sheet and the structure, pressing the reinforcing fiber sheet against the structure with the sealing sheet, and impregnating the thermoplastic resin into the gaps in the reinforcing fiber sheet and the voids or gaps present on the surface of the structure; a final fixing process in which the thermoplastic resin is cooled and hardened, and the reinforcing fiber sheet is finally fixed to the structure via the thermoplastic resin; and a peeling process in which the sealing sheet is peeled off from the reinforcing fiber sheet.

[0008] According to the above invention, the reinforcing fiber sheet has an adhesive layer formed by pre-applying a thermoplastic resin raw material to at least one side thereof, or is pre-impregnated with a thermoplastic resin raw material. Therefore, for example, a process of applying an adhesive or the like to the structure is not required, and the process can be as simple as simply contacting the adhesive layer or reinforcing fiber sheet with the structure, thereby improving the workability of construction work for reinforcing or repairing structures.

[0009] Furthermore, gases such as water vapor are generated from the application surface during the heating, melting, and polymerization of the thermoplastic resin. However, in the present invention, the sealing sheet enclosing the reinforcing fiber sheet is evacuated to a vacuum during the heating, melting, and polymerization of the thermoplastic resin. Therefore, the gases do not become an obstacle that prevents the adhesion of the reinforcing fiber sheet to the structure. Furthermore, since the reinforcing fiber sheet is enclosed by the sealing sheet, reinforcement or repair of structures is possible even in wet conditions and even underwater.

[0010] Furthermore, due to the above-mentioned vacuum evacuation, the sealing sheet compresses the reinforcing fiber sheet and presses the reinforcing wire sheet against the structure, so that the thermoplastic resin can easily penetrate into the gaps in the reinforcing fiber sheet and even into voids or gaps present on the surface of the structure, and function more effectively as an adhesive between the reinforcing fiber sheet and the structure.

[0011] Furthermore, since the raw material for the thermoplastic resin contains unpolymerized portions, even at temperatures below a predetermined temperature and above a predetermined humidity, it temporarily becomes low in viscosity when heated, melted, and polymerized. This makes it easier for the thermoplastic resin to be impregnated into the gaps in the reinforcing fiber sheet and into voids or gaps present on the surface of the structure, thereby enabling the reinforcing fiber sheet to be securely fixed to the structure.

[0012] Furthermore, the thermoplastic resin raw material containing the unpolymerized portion becomes less sticky at relatively low temperatures such as room temperature, and furthermore, it becomes easier to ensure adhesion to the structure during evacuation, and there is no problem with the evacuation of gas during heating, melting, and polymerization, thereby improving the construction environment.

[0013] The reinforcing fiber sheet may be a prepreg sheet that has been impregnated in advance with a polymerized resin raw material, and the coating step may be carried out on the reinforcing fiber sheet that has been made into a prepreg sheet.

[0014] According to the above aspect, the reinforcing fiber sheet is a prepreg sheet with improved rigidity and strength compared to ordinary sheets, and therefore can further increase the strength of reinforcement and repair of structures and broaden the range of applications.

[0015] In the method for reinforcing or repairing a structure according to the present invention, the sealing sheet is pre-bonded to the reinforcing fiber sheet in a releasable manner with a bonding strength lower than the bonding strength of the reinforcing fiber sheet to the structure during the main fixing process, so that the reinforcing fiber sheet and the sealing sheet are integrated, and by temporarily fixing the reinforcing fiber sheet to the structure, at least a portion of the peripheral edge of the reinforcing fiber sheet on the structure is encompassed by at least a sealing sheet, and the sealing sheet is sealed, so that the temporary fixing process and the sealing process may be performed simultaneously.

[0016] According to the above aspect, the sealing sheet is pre-bonded to the reinforcing fiber sheet in a releasable manner, so the reinforcing fiber sheet can be configured to have not only the adhesive layer but also the sealing sheet bonded to it, thereby further improving the workability of construction work to reinforce or repair structures.

[0017] Furthermore, since the sealing sheet is bonded to the reinforcing fiber sheet with a bonding strength that is lower than the bonding strength of the reinforcing fiber sheet to the structure during this fixing process, the sealing sheet can be reliably peeled off from the reinforcing fiber sheet during the peeling process.

[0018] In the method for reinforcing or repairing a structure according to the present invention, the structure may be made of at least one material selected from concrete, wooden structural members, steel structural members, and resin-reinforced continuous fiber members, and the thermoplastic resin raw material may be melted and polymerized at a temperature of 80°C or higher and 250°C or lower.

[0019] According to the above-mentioned aspect, the thermoplastic resin can be sufficiently heated, melted, and polymerized to exhibit its adhesive properties, while making it difficult for the structure to deteriorate, thereby reliably fixing the reinforcing fiber sheet to the structure.

[0020] In the method for reinforcing or repairing a structure according to the present invention, the thermoplastic resin raw material may be melted and polymerized at a temperature of 110°C or higher and 160°C or lower.

[0021] According to the above aspect, the structure can be made less susceptible to deterioration, and the thermoplastic resin can be appropriately heated, melted, and polymerized, thereby enabling the reinforcing fiber sheet to be securely and effectively fixed to the structure. [Effects of the Invention]

[0022] According to the present invention, the reinforcing fiber sheet has an adhesive layer formed on at least one side by pre-applying a thermoplastic resin raw material, or is pre-impregnated with a thermoplastic resin raw material, so that the process can be simplified by simply contacting the adhesive layer or reinforcing fiber sheet with the structure, thereby improving the workability of construction work to reinforce or repair the structure. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is an explanatory view showing a first step in one embodiment of a method for reinforcing or repairing a structure according to the present invention. [Figure 2] FIG. 10 is an explanatory diagram showing the second step of the method for reinforcing or repairing the structure. [Figure 3] FIG. 10 is an explanatory diagram showing the third step of the method for reinforcing or repairing the structure. [Figure 4] FIG. 10 is an explanatory diagram showing the fourth step of the method for reinforcing or repairing the structure. [Figure 5] FIG. 4 is an explanatory view showing a first step in another embodiment of the method for reinforcing or repairing a structure according to the present invention. [Figure 6] FIG. 10 is an explanatory diagram showing the second step of the method for reinforcing or repairing the structure. DETAILED DESCRIPTION OF THE INVENTION

[0024] (One embodiment of a method for reinforcing or repairing a structure) Hereinafter, one embodiment of a method for reinforcing or repairing a structure according to the present invention will be described with reference to FIGS.

[0025] This method for reinforcing or repairing a structure (hereinafter simply referred to as the "repair method") is a method for reinforcing or repairing a structure 1 such as a concrete structure or a wooden structure by adhering a reinforcing fiber sheet 10 (hereinafter simply referred to as the "fiber sheet 10") to the structure 1, and includes the following steps: (1) an application step, (2) a temporary fixing step, (3) a sealing step, (4) a heat impregnation step, (5) a permanent fixing step, and (6) a peeling step, as described below.

[0026] The structure 1 is made of at least one material selected from the group consisting of concrete, wooden structural members, steel structural members, and resin-reinforced continuous fiber members, and may be made of a combination of two or more of these materials.

[0027] As the fiber sheet 10, for example, a high-strength fiber sheet such as a carbon fiber sheet and / or a glass fiber sheet, or a relatively flexible and stretchable fiber sheet such as an aramid fiber sheet can be used. In this specification, the expression "A and / or B" means "at least one of A and B."

[0028] The former, high-strength fiber sheet, is primarily focused on strength and is suitable for use on the underside of bridges, for example, while the latter, flexible and highly stretchable fiber sheet, is suitable for use in areas that require flexibility in addition to strength, such as the corners of concrete blocks.

[0029] Furthermore, since carbon fiber sheets and the like are electrically conductive, when used to reinforce the interior of a railway vehicle tunnel, for example, they are expected to have an adverse effect on the railway vehicle's pantographs, etc. Therefore, for reinforcing or repairing such structures, aramid fiber sheets and / or glass fiber sheets are preferred. The reinforcing fiber sheets are generally formed by knitting or weaving reinforcing fibers into a long cloth shape.

[0030] As shown in Fig. 1, at least one surface (one surface in the thickness direction, the bottom surface in Fig. 1) of the fiber sheet 10 is coated in advance with a thermoplastic resin raw material containing an unpolymerized portion in the coating step (1) to form an adhesive layer 20. This adhesive layer 20 exhibits adhesiveness to the fiber sheet 10 and is integrated with the fiber sheet 10. Furthermore, this adhesive layer 20 also exhibits adhesiveness to the structure 1. This adhesive layer 20 is made of a material selected from, for example, thermoplastic epoxy resins.

[0031] Of the thermoplastic resins constituting the adhesive layer 20, the thermoplastic epoxy resin contains (a) a first bifunctional compound having two epoxy groups and (b) a second bifunctional compound having two of at least one functional group selected from the group consisting of a phenolic hydroxyl group, an amino group, a carboxyl group, a mercapto group, an isocyanate group, and a cyanate ester group.

[0032] The thermoplastic resin in this embodiment contains a polymerized portion in which the compounds (a) and (b) are linearly polymerized by a polyaddition reaction, and an unpolymerized portion in which the compounds (a) and (b) are not linearly polymerized by a polyaddition reaction.

[0033] As shown below, thermoplastic epoxy resins particularly have hydroxyl groups, which react with the structure 1 and the fiber sheet 10, and are therefore presumed to exhibit adhesive properties to these.

[0034] Examples of the (a) first bifunctional compound having two epoxy groups include mononuclear aromatic diepoxy compounds having one benzene ring, such as catechol diglycidyl ether, resorcinol diglycidyl ether, t-butylhydroquinone diglycidyl ether, and phthalic acid diglycidyl ether; alicyclic epoxy compounds, such as dimethylolcyclohexane diglycidyl ether, 3,4-epoxycyclohexenylmethyl-3,4-epoxycyclohexenylcarboxylate, and limonene dioxide; bis(4-hydroxyphenyl)-2-(4-hydroxyphenyl)-2-propanol; Examples of bisphenol epoxy compounds include bisphenol-type epoxy compounds such as 1,1-bis(4-hydroxyphenyl)methane diglycidyl ether, 1,1-bis(4-hydroxyphenyl)ethane diglycidyl ether, and 2,2-bis(4-hydroxyphenyl)propane diglycidyl ether, as well as oligomer mixtures (bisphenol-type epoxy resins) obtained by partial condensation of these compounds, 3,3',5,5'-tetramethylbis(4-hydroxyphenyl)methane diglycidyl ether, and 3,3',5,5'-tetramethylbis(4-hydroxyphenyl)ether diglycidyl ether.

[0035] In addition, epoxy resins that exhibit crystallinity when used alone and are solid at room temperature but melt to become liquid at a temperature of 200°C or lower, such as hydroquinone diglycidyl ether, methylhydroquinone diglycidyl ether, 2,5-di-t-butylhydroquinone diglycidyl ether, biphenyl-type or tetramethylbiphenyl-type epoxy resins, bisphenolfluorene-type or biscresolfluorene-type epoxy resins, can be used.

[0036] As the (b) second bifunctional compound having two of at least one functional group selected from the group consisting of a phenolic hydroxyl group, an amino group, a carboxyl group, a mercapto group, an isocyanate group, and a cyanate ester group, for example, a compound having two phenolic hydroxyl groups in one molecule is preferred.

[0037] Examples of this type of compound include mononuclear aromatic dihydroxy compounds having one benzene ring, such as catechol, resorcinol, hydroquinone, methylhydroquinone, t-butylhydroquinone, and 2,5-di-t-butylhydroquinone; bisphenols, such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 1,1-bis(4-hydroxyphenyl)ethane (bisphenol AD), bis(hydroxyphenyl)methane (bisphenol F), bisphenolfluorene, and biscresolfluorene; compounds having condensed rings, such as dihydroxynaphthalene; and bifunctional phenol compounds having an allyl group introduced therein, such as diallylresorcinol, diallylbisphenol A, and triallyldihydroxybiphenyl.

[0038] Furthermore, the thermoplastic resin is cooled in the "(5) main fixing step." During this cooling process, stress is generated due to shrinkage, which can result in insufficient or inconsistent adhesive performance of the adhesive layer made of the thermoplastic resin. To mitigate the stress generated during cooling, a compound capable of imparting flexibility may be mixed and copolymerized with each of the above-mentioned compounds constituting the thermoplastic resin. As a result, flexibility is imparted to the thermoplastic resin, making it possible to mitigate the stress during cooling. Examples of compounds capable of imparting flexibility include compounds in which core-shell rubber particles are monodispersed in an epoxy resin at a high concentration (25 to 40%) (e.g., Kane Ace (registered trademark) MX-257, manufactured by Kaneka Corporation).

[0039] When the compound (a) and the compound (b) in the above thermoplastic epoxy resin contain polymerized portions that have been linearly polymerized by a polyaddition reaction, these polymerized portions can be linearly polymerized by a polyaddition reaction as exemplified below. The linear polymerization can be confirmed by solubility in solvents, thermal melting properties, etc. However, the presence of a crosslinked structure in part is not excluded as long as it does not impede the object of the present invention.

[0040] [ka] The polymerization catalyst used in the polymerization reaction includes phosphorus-based catalysts, 1,2-alkylenebenzimidazole (TBZ), and 2-aryl-4,5-diphenylimidazole (NPZ). These are used alone or in combination of two or more. Phosphorus-based catalysts are preferred because they improve reflowability.

[0041] Examples of the phosphorus catalyst include dicyclohexylphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, cyclohexyldiphenylphosphine, triphenylphosphine, triphenylphosphine-triphenylborane complex, and tri-m-tolylphosphine-triphenylborane complex.

[0042] The amount of the polymerization catalyst used is usually 0.1 to 10 parts by mass, preferably 0.4 to 6 parts by mass, and particularly preferably 1 to 5 parts by mass, relative to 100 parts by mass of the compound (a), from the viewpoint of achieving an excellent balance between short-time polymerizability and usable time.

[0043] Furthermore, the thermoplastic resin raw material constituting the adhesive layer 20 is preferably heated to melt and polymerize at a temperature of 80°C or higher and 250°C or lower, and more preferably heated to melt and polymerize at a temperature of 110°C or higher and 160°C or lower. If the temperature is lower than 80°C, it becomes difficult to heat-melt and polymerize the adhesive layer 20, and if the temperature exceeds 250°C, deterioration of the structure 1 may occur. Note that the lower limit of the temperature at which the thermoplastic resin raw material can be melted and polymerized is preferably 110°C, and more preferably 150°C.

[0044] Furthermore, on the surface of the fiber sheet 10 opposite to the surface to which the adhesive layer 20 is applied (the other surface in the thickness direction, the upper surface in FIG. 1), a sealing sheet 30 is pre-removably bonded to the fiber sheet 10 with a bonding strength lower than the bonding strength of the fiber sheet 10 to the structure 1 during this fixing step, and the fiber sheet 10 and the sealing sheet 30 are integrated together. That is, in this embodiment, the adhesive layer 20 and the sealing sheet 30 are integrally provided on both sides of the fiber sheet 10.

[0045] The sealing sheet 30 is, for example, a polymer sheet made of PTFE (polytetrafluoroethylene) or the like and has excellent heat resistance, and its outer dimensions (horizontal length, vertical length, etc.) are larger than those of the fiber sheet 10, so that it covers the entire fiber sheet 10. In other words, the sealing sheet 30 extends a predetermined length from the outer peripheral edge of the fiber sheet 10.

[0046] Next, the repair method of this embodiment will be described in detail. As described above, the repair method of this embodiment includes (1) a coating step, (2) a temporary fixing step, (3) a sealing step, (4) a heat impregnation step, (5) a permanent fixing step, and (6) a peeling step.

[0047] The application step (1) is a step of applying a thermoplastic resin raw material containing an unpolymerized portion to at least one surface of the fiber sheet 10 in advance to form an adhesive layer 20. In this embodiment, the thermoplastic resin raw material is applied to the entire lower surface of the fiber sheet 10 to form an adhesive layer 20 of a predetermined thickness (see FIG. 1).

[0048] In addition, a prepreg sheet that has been pre-impregnated with polymerized resin raw material may be used as the fiber sheet 10, and at least one side of this prepreg sheet of fiber sheet 10 may be pre-coated with thermoplastic resin raw material containing unpolymerized portions using the coating process (1) above to form the adhesive layer 20.

[0049] The temporary fixing step (2) is a step of bringing the adhesive layer 20 side of the fiber sheet 10 into contact with the structure 1 and temporarily fixing the fiber sheet 10 to the structure 1 (see FIG. 2). Note that temporary fixing means that the fiber sheet 10 is prevented from shifting relative to the structure 1 to a considerable extent, and can also be said to temporarily hold the fiber sheet 10 to the structure 1.

[0050] Specifically, as shown in Fig. 1, a fiber sheet 10 having an adhesive layer 20 formed on one side and a sealing sheet 30 bonded to the other side is brought close to the surface of the structure 1 with the adhesive layer 20 side facing the structure 1, and the fiber sheet 10 is placed on the surface of the structure 1 via the adhesive layer 20 (see Fig. 2). In this case, the fiber sheet 10 is temporarily fixed to the structure 1 to a considerable extent mainly by the frictional force between the surface of the structure 1 and the underside of the adhesive layer 20 (the surface facing the surface of the structure).

[0051] The sealing step (3) is a step of covering at least a part of the peripheral edge of the fiber sheet 10 on the structure 1 with at least a sealing sheet 30 and sealing the sealing sheet 30, as shown in FIG.

[0052] Specifically, the peripheral portion 31 of the sealing sheet 30, which is bonded to the side opposite the adhesive layer 20 of the fiber sheet 10 indirectly placed on the surface of the structure 1 via the adhesive layer 20, is bonded to the surface of the structure 1 with a bonding member 40 such as masking tape, thereby sealing the sealing sheet 30 so that there is no gap between the sealing sheet 30 and the surface of the structure 1.

[0053] At this time, in a state where tension is applied to the middle portion 33 of the encapsulating sheet 30, that is, in a state where the peripheral portion 31 of the encapsulating sheet 30 is pulled, the peripheral portion 31 is joined to the structure 1 by the joining member 40. As a result, the middle portion 33 of the encapsulating sheet 30 presses the fiber sheet 10 in a direction approaching the surface of the structure 1, and the fiber sheet 10 comes into indirect contact with the surface of the structure 1 via the adhesive layer 20, so that the fiber sheet 10 is temporarily fixed to the structure 1.

[0054] That is, in this embodiment, the sealing sheet 30 and the bonding member 40 serve as temporary fixing means for temporarily fixing the fiber sheet 10, but the temporary fixing means may also be, for example, such that adhesive force is generated in the adhesive layer 20 itself before it is heated, melted, and polymerized, and the fiber sheet 10 is temporarily fixed to the structure 1 by this adhesive layer 20, and is not particularly limited thereto.

[0055] In addition, covering (or enveloping) at least a portion of the peripheral portion of the fiber sheet 10 with the sealing sheet 30 not only means that the sealing sheet 30 is in direct contact with the outer periphery of the peripheral portion of the fiber sheet 10 and directly covers the peripheral portion, but also that the sealing sheet 30 is positioned with a predetermined gap between it and the outer periphery of the peripheral portion of the fiber sheet 10 and indirectly covers the outer periphery of the peripheral portion, so to speak.

[0056] Furthermore, as shown in Figure 2, when the peripheral portion 31 of the sealing sheet 30 is joined to the structure 1, an internal space R is defined (or can be said to be defined) between the structure 1, the sealing sheet 30, the fiber sheet 10, and the adhesive layer 20.

[0057] As shown in FIG. 3, the heating impregnation step (4) is a step in which the thermoplastic resin raw material of the adhesive layer 20 is heated to melt and polymerize it, the internal space R defined by the encapsulating sheet 30 and the structure 1 is evacuated, and the encapsulating sheet 30 presses the fiber sheet 10 against the structure 1 (i.e., the encapsulating sheet 30 presses the adhesive layer 20 against the fiber sheet 10, or the fiber sheet 10 against the adhesive layer 20), and the thermoplastic resin is impregnated into the gaps in the fiber sheet 10 and the voids or gaps present on the surface of the structure 1.

[0058] Specifically, a heating means 50 such as a far-infrared heater is disposed outside the sealing sheet 30, and the adhesive layer 20 is heated by the heating means 50 to melt the thermoplastic resin and polymerize the unpolymerized portion. At the same time, a suction unit 60 such as a vacuum suction device (not shown) is inserted into the internal space R, and the suction unit 60 sucks air from the internal space R to evacuate it.

[0059] As a result, the sealing sheet 30 is sucked in and the fiber sheet 10 is pressed (compressed), and the adhesive layer 20 is pressed through this fiber sheet 10, and the thermoplastic resin that has been heated, melted, and polymerized penetrates (impregnates) into the gaps in the fiber sheet 10 and the voids or gaps present on the surface of the structure 1.

[0060] Furthermore, in this embodiment, as described above, the sealing sheet 30 is pre-bonded to the fiber sheet 10 in a peelable manner with a bonding strength lower than the bonding strength of the fiber sheet 10 to the structure 1 during this fixing process, and by contacting the adhesive layer 20 with the structure 1 and temporarily fixing the fiber sheet 10 to the structure 1, at least a portion of the peripheral portion of the fiber sheet 10 on the structure 1 is encompassed by at least the sealing sheet 30, and the sealing sheet 30 is sealed, so that the temporary fixing process (2) and the sealing process (3) are performed simultaneously.

[0061] It is needless to say that the temporary fixing step (2) and the sealing step (3) may be carried out separately.

[0062] The above-mentioned (5) permanent fixing step is a step of cooling and hardening the adhesive layer 20, and permanently fixing the fiber sheet 10 to the structure 1 via the adhesive layer 20 (see FIG. 3). Specifically, the step waits until the thermoplastic resin that has been impregnated into the gaps in the fiber sheet 10 and the voids or gaps present on the surface of the structure 1, has been heated, melted, and polymerized, and has cooled and hardened. This allows the adhesive properties of the adhesive layer 20 to be developed, allowing the fiber sheet 10 to be permanently fixed to the structure 1.

[0063] The peeling step (6) above is a step of peeling the sealing sheet 30 from the fiber sheet 10. Specifically, by peeling the sealing sheet 30 from the fiber sheet 10 that has been fully fixed to the structure 1, only the fiber sheet 10 remains on the surface of the structure 1, and the reinforcement or repair work for the structure 1 is completed.

[0064] In the above-mentioned heat impregnation step (4), gases such as water vapor are generated from the application surface of the structure 1 when the thermoplastic resin of the adhesive layer 20 is heated, melted, and polymerized. However, in the present invention, when the thermoplastic resin of the adhesive layer 20 is heated, melted, and polymerized, the internal space R of the sealing sheet 30 that encloses the fiber sheet 10 on which the adhesive layer 20 is formed is evacuated to a vacuum. Therefore, the gases do not become an obstacle that prevents the fiber sheet 10 from adhering to the structure 1 via the adhesive layer 20.

[0065] In addition, since the fiber sheet 10 including the adhesive layer 20 is wrapped in the sealing sheet 30, the structure 1 can be reinforced or repaired even in wet conditions, or even underwater.

[0066] Furthermore, due to the above-mentioned vacuum evacuation, the adhesive layer 20 is compressed by the fiber sheet 10 through the sealing sheet 30, so that the heated, melted and polymerized thermoplastic resin of the adhesive layer 20 penetrates well into the gaps in the fiber sheet 10 and also into voids or gaps present on the surface of the structure 1, allowing it to function more effectively as an adhesive between the fiber sheet 10 and the structure 1.

[0067] (Action and effect) Next, the effects of the repair method will be described.

[0068] In other words, since the fiber sheet 10 has an adhesive layer 20 formed by previously applying a thermoplastic resin raw material to at least one side thereof, there is no need for a process such as applying an adhesive to the structure 1, and the process can be as simple as simply contacting the adhesive layer 20 of the fiber sheet 10 with the structure 1, thereby improving the workability of construction work to reinforce or repair the structure 1.

[0069] Incidentally, it is known that thermosetting adhesives generally do not cure in humid environments above a certain humidity level (for example, humidity of 85% or higher), and even adhesives for winter use are known not to cure below a certain temperature (for example, below 5°C). Furthermore, many thermosetting adhesives (for example, two-component epoxy adhesives) have strong adhesive strength, are sticky, and have a strong odor, which creates concerns about the construction environment.

[0070] In contrast, in this repair method, the thermoplastic resin raw material contains unpolymerized portions, so even if the temperature is below a specified temperature and the humidity is above a specified humidity (for example, below 5°C and above 85%), it temporarily becomes low viscosity when heated, melted, and polymerized, making it easier to impregnate the gaps in the reinforcing fiber sheet and the voids or gaps present on the surface of the structure 1, thereby allowing the fiber sheet 10 to be securely fixed to the structure 1.

[0071] Furthermore, thermoplastic resin raw materials containing unpolymerized portions are less sticky at relatively low temperatures such as room temperature, and furthermore, adhesion to structures during evacuation is more easily ensured. There is also no problem with exhausting gases during heating and melting, thereby improving the construction environment.

[0072] Furthermore, in this embodiment, the sealing sheet 30 is pre-bonded to the fiber sheet 10 in a peelable manner with a bonding strength lower than the bonding strength of the fiber sheet 10 to the structure 1 during the main fixing process, and the temporary fixing process (2) and the sealing process (3) are performed simultaneously.

[0073] According to the above embodiment, the sealing sheet 30 is pre-bonded to the fiber sheet 10 in a peelable manner, so the fiber sheet 10 can be configured to have not only the adhesive layer 20 but also the sealing sheet 30 bonded thereto, thereby further improving the workability of construction work to reinforce or repair the structure 1.

[0074] Furthermore, since the sealing sheet 30 is bonded to the fiber sheet 10 with a bonding strength lower than the bonding strength of the fiber sheet 10 to the structure 1 during this fixing process, the sealing sheet 30 can be reliably peeled off from the fiber sheet 10 in the peeling process (6) above.

[0075] In this embodiment, the structure 1 is made of at least one material selected from concrete, wooden structural members, steel structural members, and resin-reinforced continuous fiber members, and the thermoplastic resin raw material is melted and polymerized at a temperature of 80°C or higher and 250°C or lower.

[0076] According to the above embodiment, the structure 1, which is concrete or the like, is less likely to deteriorate, while the thermoplastic resin of the adhesive layer 20 is sufficiently heated, melted, and polymerized to exhibit its adhesive properties, thereby reliably fixing the fiber sheet 10 to the structure 1.

[0077] Furthermore, in this embodiment, the thermoplastic resin raw material is melted and polymerized at a temperature of 110°C or higher and 160°C or lower.

[0078] According to the above embodiment, the structure 1 is made less susceptible to deterioration, and the thermoplastic resin of the adhesive layer 20 is appropriately heated, melted, and polymerized, thereby enabling the fiber sheet 10 to be reliably and efficiently fixed to the structure 1.

[0079] Furthermore, as explained in paragraph 0048, the fiber sheet 10 is a prepreg sheet that has been pre-impregnated with polymerized resin raw material, and when the application process (1) above is performed on the prepreg fiber sheet 10, the following effects are achieved.

[0080] In other words, the fiber sheet 10 is a prepreg sheet with improved rigidity and strength compared to ordinary sheets, and therefore can further increase the strength of reinforcement and repair of the structure 1 and broaden the range of applications.

[0081] Furthermore, as explained in paragraph 0038, the thermoplastic resin is formed by mixing and copolymerizing each of the compounds constituting the thermoplastic resin described in paragraphs 0034 to 0037 with a compound capable of imparting flexibility. In this case, flexibility is imparted to the thermoplastic resin, so that stress during cooling during the main fixing of the thermoplastic resin can be alleviated, and the adhesive performance of the adhesive layer made of the thermoplastic resin can be fully exerted, and the adhesive performance can be uniformly generated throughout the adhesive layer.

[0082] (Another embodiment of the method for reinforcing or repairing a structure) 5 and 6, an embodiment of a method for reinforcing or repairing a structure according to the present invention will be described. Note that parts that are substantially the same as those in the above embodiment will be given the same reference numerals and descriptions thereof will be omitted.

[0083] This method of reinforcing or repairing a structure (hereinafter simply referred to as the "repair method") includes the following steps for the concrete structure 1: (1) raw material impregnation process, (2) temporary fixing process, (3) sealing process, (4) heat impregnation process, (5) permanent fixing process, and (6) peeling process, as described below.

[0084] The raw material impregnation step (1) is a step of pre-impregnating a reinforcing fiber sheet 10A (hereinafter simply referred to as "fiber sheet 10A") with a thermoplastic resin raw material containing an unpolymerized portion. In this embodiment, the entire fiber sheet 10A is impregnated with the thermoplastic resin raw material (see FIG. 5).

[0085] The temporary fixing step (2) is a step of bringing the fiber sheet 10A into contact with the structure 1 and temporarily fixing the fiber sheet 10A to the structure 1. In this embodiment, as shown in Fig. 6, the lower surface of the fiber sheet 10A having the sealing sheet 30 bonded to the upper surface thereof is placed on the surface of the structure 1.

[0086] The sealing step (3) above is a step of covering at least a part of the peripheral edge of the fiber sheet 10A on the structure 1 with at least the sealing sheet 30 and sealing the sealing sheet 30, which is the same as the sealing step in the above embodiment.

[0087] The heating and impregnation process (4) is a process in which the thermoplastic resin raw material is heated to melt and polymerize it, the internal space R defined by the sealing sheet 30 and the structure 1 is evacuated, the sealing sheet 30 presses the fiber sheet 10 against the structure 1, and the thermoplastic resin is impregnated into the gaps in the fiber sheet 10 and the voids or gaps present on the surface of the structure 1, and is the same as the sealing process in the above embodiment.

[0088] The above-mentioned (5) main fixing step is a step of cooling and hardening the thermoplastic resin, and main fixing the fiber sheet 10A to the structure 1 via the thermoplastic resin, and is the same as the main fixing step in the above-described embodiment.

[0089] The peeling step (6) above is a step of peeling the sealing sheet 30 from the fiber sheet 10A, and is the same as the peeling step in the above embodiment.

[0090] In this embodiment, the fiber sheet 10A is pre-impregnated with the thermoplastic resin raw material, so that, for example, a process of applying an adhesive or the like to the structure 1 is not required, and the process can be as simple as simply contacting the fiber sheet 10A with the structure 1, thereby improving the workability of construction work to reinforce or repair the structure 1.

[0091] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and / or modifications thereof are included within the scope and / or spirit of the invention, and are also included in the scope of the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0092] 1... structure, 10, 10A... reinforcing fiber sheet (fiber sheet), 20... adhesive layer, 30... sealing sheet, 40... joining member, 50... heating means, 60... suction part, R... internal space.

Claims

1. A method for reinforcing or repairing a structure by adhering a reinforcing fiber sheet to the structure, comprising: a coating step of coating a thermoplastic resin raw material containing an unpolymerized portion on at least one surface of the reinforcing fiber sheet in advance to form an adhesive layer; a temporary fixing step of contacting the adhesive layer side of the reinforcing fiber sheet with the structure and temporarily fixing the reinforcing fiber sheet to the structure; a sealing step of covering at least a portion of the peripheral edge of the reinforcing fiber sheet with a sealing sheet on the structure and sealing the sealing sheet; a heating and impregnation process in which the raw material of the thermoplastic resin of the adhesive layer is heated to melt and polymerize it, the internal space defined by the sealing sheet and the structure is evacuated to a vacuum, the sealing sheet presses the reinforcing fiber sheet against the structure, and the thermoplastic resin is impregnated into the gaps in the reinforcing fiber sheet and the voids or gaps present on the surface of the structure; a final fixing step of cooling and hardening the thermoplastic resin and finally fixing the reinforcing fiber sheet to the structure via the adhesive layer; and a peeling step of peeling the sealing sheet from the reinforcing fiber sheet.

2. 2. A method for reinforcing or repairing a structure as described in claim 1, wherein the reinforcing fiber sheet is a prepreg sheet that has been pre-impregnated with polymerized resin raw material, and the coating process is performed on the reinforcing fiber sheet that has been prepreg sheeted.

3. A method for reinforcing or repairing a structure by adhering a reinforcing fiber sheet to the structure, comprising: a raw material impregnation step of pre-impregnating the reinforcing fiber sheet with a raw material for a thermoplastic resin containing an unpolymerized portion; a temporary fixing step of bringing the reinforcing fiber sheet into contact with the structure and temporarily fixing the reinforcing fiber sheet to the structure; a sealing step of covering at least a portion of the peripheral edge of the reinforcing fiber sheet with a sealing sheet on the structure and sealing the sealing sheet; a heating and impregnation step of heating and melting and polymerizing the raw material of the thermoplastic resin, evacuating the internal space defined by the sealing sheet and the structure, pressing the reinforcing fiber sheet against the structure with the sealing sheet, and impregnating the thermoplastic resin into gaps in the reinforcing fiber sheet and voids or gaps present on the surface of the structure; a final fixing step of cooling and hardening the thermoplastic resin and final fixing the reinforcing fiber sheet to the structure via the thermoplastic resin; and a peeling step of peeling the sealing sheet from the reinforcing fiber sheet.

4. The sealing sheet is pre-peelably bonded to the reinforcing fiber sheet with a bonding strength lower than the bonding strength of the reinforcing fiber sheet to the structure during the main fixing step, and the reinforcing fiber sheet and the sealing sheet are integrated, A method for reinforcing or repairing a structure as described in claim 1 or 3, wherein by temporarily fixing the reinforcing fiber sheet to the structure, at least a portion of the peripheral edge of the reinforcing fiber sheet on the structure is covered by at least a sealing sheet, and the sealing sheet is sealed so that the temporary fixing process and the sealing process are performed simultaneously.

5. The structure is made of at least one material selected from concrete, wooden structural members, steel structural members, and resin-reinforced continuous fiber members, 4. The method for reinforcing or repairing a structure according to claim 1, wherein the thermoplastic resin raw material is melted and polymerized at a temperature of 80°C or higher and 250°C or lower.

6. 6. The method for reinforcing or repairing a structure according to claim 5, wherein the raw material of the thermoplastic resin is melted and polymerized at a temperature of 110°C or higher and 160°C or lower.

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