Reinforcement method and sealing jig

Abstract

The present invention addresses the problem of providing a method with which it is possible, at a construction site having many restrictions, to reinforce a reinforcement target by using a highly viscous adhesive.　The present invention relates to a reinforcement method for reinforcing a reinforcement target by using an adhesive to adhere a FRP reinforcement material thereto, wherein, after the adhesive and the FRP reinforcement material have been arranged in this order on the reinforcement target, the FRP reinforcement material is sealed using a sealing film, air that has been sealed in by the sealing film is evacuated by using a portable implement, and the FRP reinforcement material is adhered to the reinforcement target by pressure bonding.

Description

Reinforcement method and sealing jig

[0001] The present invention relates to a method for reinforcing a structure using an FRP reinforcing material and a sealing jig, and more particularly to a method for repairing and reinforcing a structure using a high-viscosity adhesive.

[0002] One known method for reinforcing existing bridges, buildings, and the like is to bond fiber-reinforced plastic (hereinafter referred to as FRP) to the surface. Common methods for bonding FRP include a hand layup method in which a dry reinforcing fiber sheet is coated with a room-temperature curing resin on-site and then impregnated and cured with an impregnation roller or the like, thereby reinforcing the structure, and a method in which factory-formed FRP reinforcing material is attached with a putty-like adhesive. The method of reinforcing by attaching FRP reinforcing material with a putty-like adhesive is adopted as a concrete reinforcement method because it requires less work time at the construction site and fewer materials.

[0003] Japanese Unexamined Patent Publication No. 52-125541

[0004] On the other hand, adhesives used in construction methods for adhesively attaching FRP reinforcement to the target to be reinforced generally contain various fillers to hold the FRP reinforcement in place or enhance its functionality, making them highly viscous and requiring the FRP reinforcement to be pressed against the target with great force. When attaching an FRP reinforcement, the FRP reinforcement is manually bent and the adhesive is gradually applied while being squeezed out. However, if the FRP reinforcement is not sufficiently rigid or wide, it is difficult to manually bend the FRP reinforcement, making it difficult to thin the adhesive layer and thus preventing the intended reinforcement effect. Furthermore, when using high-viscosity adhesives, air is easily trapped in the adhesive during mixing and crimping. When using adhesives containing air, air remains in the adhesive layer, which can impair the adhesion between the FRP reinforcement and the target to be reinforced.

[0005] To solve the above problems, Patent Document 1 describes a method in which an adhesive is sandwiched between an FRP reinforcing material and an object to be reinforced, the adhesive is sealed, the pressure is reduced, and the FRP reinforcing material is pressure-bonded to the object to be reinforced at atmospheric pressure. However, this method requires large, dedicated equipment, and there are limitations on the tools and jigs that can be brought into construction sites that are confined or require rope access.

[0006] The present invention has been made with the objective of providing a method for reinforcing an object to be reinforced using a high-viscosity adhesive in a construction site with many restrictions.

[0007] To solve the above problems, the present invention and its preferred embodiments have the following configurations: (1) A reinforcement method for attaching an FRP reinforcing material to an object to be reinforced with an adhesive, the reinforcement method comprising: placing the adhesive and the FRP reinforcing material on the object to be reinforced in that order; sealing the FRP reinforcing material with a sealing film; and using a portable tool to evacuate the air inside the sealing film and pressurize the FRP reinforcing material onto the object to be reinforced. (2) The reinforcement method described in (1), in which the object to be reinforced is a steel material, and the FRP reinforcing material is sealed with the sealing film using a sealing jig that includes at least a magnet, a frame, the sealing film, and a vacuum port and can be fixed to the object to be reinforced with the magnet. (3) The reinforcement method described in (2), in which grease is applied between the magnet and the object to be reinforced during sealing. (4) The reinforcement method described in any one of (1) to (3), in which the portable tool is a non-electric portable tool. (5) A sealing jig used when reinforcing an FRP reinforcement material by attaching it to a steel reinforcement object with an adhesive, the sealing jig comprising at least a magnet, a frame, a sealing film and a vacuum port, and capable of being fixed to the steel reinforcement object by the magnet.

[0008] According to the present invention, even at construction sites with many restrictions, reinforcement of the target structure with an FRP reinforcing material can be easily and quickly achieved by using a high-viscosity adhesive.

[0009] 1 is a side view of a step of crimping a reinforcing material onto an object to be reinforced by the reinforcing method of the present invention.

[0010] The present invention is a reinforcing method for reinforcing an object by attaching an FRP reinforcing material to the object with an adhesive.

[0011] The reinforcing fibers used in the FRP reinforcing material are not particularly limited as long as they are reinforcing fibers that can be used in FRP, such as carbon fiber, glass fiber, and aramid fiber, but carbon fiber is preferred because of its excellent strength and elastic modulus. Examples of the carbon fiber that can be used include polyacrylonitrile-based carbon fiber, rayon-based carbon fiber, and pitch-based carbon fiber. Among these, polyacrylonitrile-based carbon fiber, which has high tensile strength, is particularly preferred. Examples of the form of the carbon fiber that can be used include twisted yarn, untwisted yarn, and non-twisted yarn.

[0012] The carbon fiber preferably has a tensile modulus of elasticity in the range of 180 to 600 GPa. If the tensile modulus is within this range, the stiffness of the resulting FRP reinforcing material can be made equal to or greater than that of the reinforced object, particularly when the reinforcement target is a steel material, making reinforcement design easier. Here, the tensile modulus of elasticity of the carbon fiber is a value measured in accordance with JIS R7601-2006.

[0013] Examples of commercially available carbon fibers include "TORAYCA (registered trademark)" T300 (tensile strength: 3.5 GPa, tensile modulus: 230 GPa), "TORAYCA (registered trademark)" T700SC (tensile strength: 4.9 GPa, tensile modulus: 230 GPa), "TORAYCA (registered trademark)" T800SC (tensile strength: 5.9 GPa, tensile modulus: 294 GPa), "TORAYCA (registered trademark)" T1100GC (tensile strength: 5.9 GPa, tensile modulus: 294 GPa), and : 7.0 GPa, tensile modulus: 324 GPa), "TORAYCA (registered trademark)" M46JB (tensile strength: 4.2 GPa, tensile modulus: 436 GPa), "TORAYCA (registered trademark)" M60JB (tensile strength: 3.8 GPa, tensile modulus: 588 GPa) (all manufactured by Toray Industries, Inc.), PX35 (tensile strength: 4.1 GPa, tensile modulus: 242 GPa) (manufactured by ZOLTEK), and the like can be mentioned.

[0014] The carbon fibers in the FRP reinforcing material may be in the form of a carbon fiber bundle, and in that case, the number of filaments in the carbon fiber bundle is not particularly limited. When a woven fabric reinforced plastic (described later) is used as the FRP reinforcing material, the number of filaments in the carbon fiber bundle is preferably 1,000 to 70,000, and more preferably 1,000 to 60,000, from the viewpoints of weaving productivity and the required tensile, compressive, and flexural moduli and strength of the FRP reinforcing material.

[0015] The form of the FRP reinforcing material is not particularly limited, but preferred examples include unidirectional fiber-reinforced plastics in which the reinforcing fibers are aligned in one direction and combined with a matrix resin described below, and woven fabric-reinforced plastics in which the reinforcing fibers are woven and then combined with a matrix resin described below.

[0016] Here, we will explain the woven fabrics that can be used for the woven fabric reinforced plastic. The weave of the woven fabric is not particularly limited, but preferred weaves include plain weave, twill weave, satin weave, ribbed weave, sash weave, sash weave, hook weave, imitation weave, and mat weave. Examples of twill weaves include three-ply twill, four-ply twill, five-ply twill, six-ply twill, stretched twill, curved twill, broken twill, jumping twill, chevron twill, ruffled twill, twisted twill, day and night twill, decorative twill, and shading twill, which can be selected depending on the properties required for the FRP reinforcing material. Examples of satin weaves include five-ply twill, seven-ply twill, eight-ply twill, ten-ply twill, irregular twill, spread twill, shading twill, mikage weave, day and night twill, and shading twill, which can be selected depending on the properties required for the FRP reinforcing material. Examples of the rib weave include warp rib weave, horizontal rib weave, and variable rib weave, and can be selected depending on the properties required of the FRP reinforcing material. Examples of the chevron weave include regular chevron weave, variable chevron weave, irregular chevron weave, variable chevron weave, and double chevron weave, and can be selected depending on the design required of the FRP reinforcing material.

[0017] As the reinforcing fibers constituting the unidirectional fiber reinforced plastic or the woven fabric reinforced plastic, carbon fiber, glass fiber, or aramid fiber may be used alone or in combination. In view of excellent performance, cost, and design, it is also preferable to interweave at least one type of glass fiber and at least one type of carbon fiber.

[0018] The matrix resin used in the FRP reinforcing material may be any of thermosetting resins such as epoxy resin, vinyl ester resin, and urethane resin, and thermoplastic resins such as nylon resin, polyphenylene sulfide resin, and polyether ether ketone resin, and the optimal resin can be selected depending on the manufacturing method and required properties of the FRP reinforcing material.

[0019] The size of the FRP reinforcing material is determined by the degree of the defect in the reinforcement target and the required amount of reinforcement, and is not particularly limited. In order to transfer the stress applied to the reinforcement target to the FRP reinforcing material, it is necessary to adhere it over an area larger than the defect. Therefore, when a rectangle circumscribing the shape of the defect is defined, it is preferable to use a reinforcing material whose side length is 30 mm or more longer than the rectangle, and more preferably 50 mm or more longer.

[0020] The material of the object to be reinforced is not particularly limited, and may be, for example, steel, concrete, wood, etc., but if the object to be reinforced is steel, it can be sealed using a magnet, making construction easier.

[0021] The adhesive is not particularly limited, but two-component adhesives such as epoxy adhesives, urethane adhesives, and acrylic adhesives, which have excellent adhesive properties, are preferred.

[0022] The viscosity of the adhesive is preferably 10 Pa·sec or more at 23°C in order to hold the FRP reinforcing material to the object to be reinforced. A viscosity of 10 Pa·sec or more prevents the FRP reinforcing material from moving due to tilt of the object to be reinforced or vibration of the structure, making it easier to properly adhere to the object to be reinforced. Furthermore, a viscosity of 30 Pa·sec or more is more preferable, so that the adhesive can support the weight of the object to be reinforced when the object to be reinforced is a vertical wall, ceiling, etc. Furthermore, in order to keep the required pressure-bonding force small, the viscosity of the adhesive is preferably 1,000 Pa·sec or less at 23°C.

[0023] The thickness of the adhesive layer between the FRP reinforcing material and the object to be reinforced after pressure bonding is preferably 2 mm or less, more preferably 1.5 mm or less. With this thickness of the adhesive layer, the force applied to the object to be reinforced can be efficiently transmitted by the FRP reinforcing material, thereby improving the reinforcement efficiency. In this invention, the thickness of the adhesive layer includes the thickness of the primer layer.

[0024] In the present invention, the adhesive and the FRP reinforcing material are first placed on the object to be reinforced, in that order, and the FRP reinforcing material is then sealed with a sealing film. That is, the periphery of the object to be reinforced is completely covered with the sealing film. Then, the air inside the sealing film is evacuated and the pressure is reduced to allow the FRP reinforcing material and the object to be reinforced to be pressure-bonded at atmospheric pressure.

[0025] The method for sealing the FRP reinforcing material may be any method that can seal the FRP reinforcing material and press the object to be reinforced with the sealing film. Preferred examples include a method of fixing the sealing film with a sealant tape, and a method of fixing the object to be reinforced with a magnet when the object to be reinforced is a steel material.

[0026] When the magnet is used for fastening, it is preferable to grease the gap between the magnet and the object to be reinforced, because even if the surface of the object to be reinforced is uneven, the inflow of air from the outside can be suppressed when the inside sealed with the sealing film is decompressed, and the degree of decompression inside the inside sealed with the sealing film can be maintained.

[0027] When the magnet is used for sealing, it is preferable to use a sealing jig that includes at least a magnet, a frame, the sealing film, and a vacuum port and that can be fixed to the reinforcement object by the magnet. The use of such a sealing jig improves work efficiency because it is easy to set up and takes a short time until crimping, and also enables the use of an adhesive with a short usable life.

[0028] In the reinforcement method of the present invention, a portable tool is used to exhaust the air sealed inside the sealing film and then press the FRP reinforcement material onto the object to be reinforced. Examples of the portable tool include a portable electric pump with a battery and a manual handgun-type pump that does not require a power source. In particular, the use of a non-electric portable tool such as a manual handgun-type pump is preferred because it allows construction in explosion-proof areas.

[0029] In particular, the combination of a sealing means using a magnet and a manual handgun-type pump can minimize the amount of materials required for construction, and is particularly effective for construction in confined spaces or with rope access.

[0030] As for the capacity of the portable tool, if the vacuum pressure that can be achieved is a relative pressure of -20 kPa or less, it is possible to remove air bubbles trapped in the adhesive and reduce the thickness of the adhesive layer between the FRP reinforcing material and the object to be reinforced to 2 mm or less, which is preferable.

[0031] Next, an example of a procedure for attaching the FRP reinforcing material to the object to be reinforced will be described, but the present invention is not limited to only the following example.

[0032] First, it is preferable to perform a surface treatment on the surface of the object to be reinforced depending on the type of object to be reinforced. The procedure for the treatment varies depending on the type and amount of adhesive used, but examples include removing corroded or defective areas, applying a primer, and correcting unevenness.

[0033] Thereafter, the bonding surfaces of the FRP reinforcing material and the reinforcement object are sanded and degreased, and then the adhesive is applied.

[0034] When using a two-component adhesive, the base agent and curing agent are mixed before bonding. Any method can be used to mix the adhesive, but a mixing method using an adhesive gun and static mixer is preferred because it reduces the risk of air bubbles being mixed in during mixing and the possibility of poor mixing.

[0035] The adhesive is applied to either or both of the FRP reinforcing material and the object to be reinforced. After applying a thin layer of adhesive to both the FRP reinforcing material and the object to be reinforced, the adhesive can be applied in a circular pattern at the center of the bonding surface or in a linear or radial pattern over the entire bonding surface of either the FRP reinforcing material or the object to be reinforced. When the FRP reinforcing material is pressed against the object, the adhesive is swept away, allowing air to be efficiently discharged.

[0036] After applying the adhesive, the FRP reinforcing material and the object to be reinforced are bonded together, the FRP reinforcing material is temporarily fixed to the object to be reinforced, and then the FRP reinforcing material is sealed with the sealing film and the air inside the sealed space is evacuated, thereby pressing the FRP reinforcing material to the object to be reinforced at atmospheric pressure.

[0037] Any method of crimping may be used. For example, if the reinforcement target is a steel material, a method such as that shown in FIG. 1 can be used in which a sealing jig including a magnet 6, a frame 5, a sealing film 1, and a vacuum port 2 is set on the reinforcement target 8 so as to cover the FRP reinforcement 4, and the air inside the sealing film 1 is evacuated and reduced in pressure using a non-electric air exhaust pump 7 connected to the vacuum port 2 via a tube, followed by crimping. Alternatively, as shown in FIG. 2, a method can be used in which a sealant tape 10 is attached around the periphery of the FRP reinforcement 4, and then a sealing jig including a pressure plate 9, the sealing film 1, and the vacuum port 2 is set on the periphery, and the air inside the sealing film 1 is evacuated and reduced in pressure using a non-electric air exhaust pump 7 connected to the vacuum port 2 via a tube, followed by crimping. The pressure plate 9 is sized so that the sealing film 1 does not touch the end of the FRP reinforcement 4. If necessary, the pressure plate 9 can be used to prevent the adhesive from adhering to the sealing jig and to ensure a flow path for the adhesive at the end of the FRP reinforcement 4.

[0038] The sealing jig of the present invention will now be described.

[0039] The sealing jig of the present invention is a sealing jig used when attaching an FRP reinforcing material to a steel reinforcement object with an adhesive, and includes at least a magnet, a frame, a sealing film, and a vacuum port, and can be fixed to the steel reinforcement object with the magnet. If necessary, a frame attached to the magnet or a jig such as a pressure plate can be used.

[0040] The magnet used in the sealing jig may be any magnet that can support the weight of the sealing jig, but it is recommended that the magnet have an adhesive force of 30 g / cm ２ The neodymium-based magnets, ferrite-based magnets, and samarium-based magnets are preferred.

[0041] The material of the sealing film is not particularly limited as long as it is capable of reducing the pressure inside the film without allowing air to pass through, but it is preferable to use a thermoplastic plastic that is stretchable and easy to peel off even if adhesive is attached, and more preferable to use silicone or PTFE.

[0042] The vacuum port may be attached at any position on the sealing film, and preferably has a structure in which the sealing film is sandwiched between the inside and outside to prevent air leakage when the pressure is reduced.

[0043] Next, the reinforcing method and sealing jig of the present invention will be described in more detail with reference to examples.

[0044] [Measurement and Evaluation Methods] (1) Adhesion Quality Adhesion quality was evaluated by carrying out the following items. If all items passed, the adhesion quality was rated A, and if any item failed, the adhesion quality was rated B.

[0045] (1-1) Visual Inspection It was evaluated whether adhesive had flowed out from the entire periphery of the FRP reinforcing material, and if adhesive had flowed out from the entire periphery, it was judged as passed, and if not, it was judged as failed.

[0046] (1-2) Hammering test The FRP reinforcement material was hammered with a hammering rod and evaluated for abnormal noise. If a hard sound, the same as when the reinforcement object was hammered, was heard, it was judged as passing, and if a light sound was heard, it was judged as failing.

[0047] (1-3) Ultrasonic Inspection An ultrasonic flaw detector was applied to the surface of the FRP reinforcement material to check for the presence or absence of a peak of the reinforcement target, and the material was evaluated. If a peak of the reinforcement target was confirmed, the material was rated as passed, and if not, the material was rated as failed.

[0048] (2) Workability The workability evaluation conducted in the examples was carried out for the following items. If all items were A+, it was rated A+; if A+ and A were mixed, it was rated A; and if there was even one item that included B, it was rated B.

[0049] (2-1) Working time If the work was completed within 20 minutes from placing the adhesive to completing the bonding of the FRP reinforcement, it was given an A+; if it was completed within the usable time of the adhesive, it was given an A; if it exceeded the usable time of the adhesive, it was given a B.

[0050] (2-2) Retention of FRP reinforcement If the position of the FRP reinforcement does not move after it is pressed, it is rated as A+; if it moves slightly when the seal is released but maintains its position, it is rated as A; if it cannot maintain its position, it is rated as B.

[0051] (3) Adhesive Layer Thickness The thickness of the adhesive layer between the FRP reinforcing material adhered to the reinforcement object and the reinforcement object was measured using an ultrasonic flaw detector. The probe of the ultrasonic flaw detector was placed on the FRP reinforcing material side to obtain a waveform with the horizontal axis representing the thickness direction of the FRP reinforcing material and the reinforcement object. The thickness of the adhesive layer was determined by subtracting the peak position (distance from the probe) of the interface between the FRP reinforcing material and the adhesive layer from the peak position (distance from the probe) of the interface between the reinforcement object and the adhesive layer. In this invention, the thickness of the adhesive layer is assumed to include the thickness of the primer layer.

[0052] [FRP Reinforcement Material] A mold having a plate-shaped cavity of 2,000 mm × 2,000 mm × 4.5 mm was filled with carbon fiber fabric UM46-40 (carbon fiber: M46J, structure: plain weave, basis weight: 400 g / m) as a reinforcing fiber in the cavity. ２Eight epoxy resin compositions (manufactured by Toray Industries, Inc.) were placed in the mold, and the mold was clamped using a press. Next, the pressure inside the mold, which was maintained at a temperature of 120°C (molding temperature), was reduced to atmospheric pressure of -0.1 MPa using a vacuum pump, and a mixed resin prepared by adding 100 parts by mass of an epoxy resin composition (TR-C38 manufactured by Toray Industries, Inc.) and 1 part by mass of an internal mold release agent (IC-35 manufactured by Chem-Trend Japan) was injected using a resin injector. The mold was opened 10 minutes after the start of injection of the mixed resin, and the resin was demolded and cut to a predetermined size, which was used as an FRP reinforcing material.

[0053] [Primer] The product numbers and properties of the primers used are as follows: E258RS (manufactured by Konishi Co., Ltd.): viscosity 105 Pa·s (23° C.), usable time 45 minutes (23° C.)).

[0054] [Adhesives] The product numbers and properties of the adhesives used are as follows: E258RS (manufactured by Konishi Co., Ltd.): viscosity 105 Pa·s (23°C), usable life 45 minutes (23°C)) E258RW (manufactured by Konishi Co., Ltd.): viscosity 49 Pa·s (23°C), usable life 25 minutes (23°C)) AUP40T1 (manufactured by Sanyu Rec Co., Ltd.): viscosity 0.6 Pa·s (23°C), usable life 40 minutes (23°C)).

[0055] [Sealing Jig] When a sealing jig was used in the examples, the sealing jig shown in Figure 1 was used. In this case, the planar size of the frame to which the magnet was attached was at least 100 mm larger per side than the size of the FRP reinforcing material to be adhered. The following components were used: Magnet: Neodymium-based magnet sheet Frame: Aluminum Sealing film: Silicone film

[0056] [Example 1] Reinforcement was carried out as follows.

[0057] The inner wall surface of the steel tank (inner diameter 2m x 3m) to be reinforced was ground to a surface preparation area of ​​170mm x 170mm using a disc grinder, the surface was finished to a type 2 finish, and degreased with a cloth soaked in acetone. After that, E258RS mixed as a primer was applied to the surface preparation area at a rate of 0.2 kg / m. ２The primer layer was applied evenly to a thickness of approximately 0.1 mm, forming a flat surface for the FRP reinforcement. After the primer layer dried, the FRP reinforcement was cut to a size of 50 mm x 50 mm. One side and the surface to which the FRP reinforcement would be attached (the surface to be reinforced) were roughened with sandpaper and degreased with a rag soaked in acetone. A thin layer of the mixed E258RS was applied to the roughened surface and the surface to be reinforced, and a comb trowel was used to apply a linear pattern of E258RS to the adhesive surface of the FRP reinforcement. The FRP reinforcement was then temporarily fixed by manually pressing it against the surface to be reinforced, and the sealing jig was placed within the surface to cover the FRP reinforcement. The sealing jig, attached to the surface with a magnet, did not shift due to its own weight.

[0058] The air was removed using an air exhaust pump (manual vacuum pump, 21 kPa; manufactured by NALGENE) and the FRP reinforcement material was pressure-bonded to the object to be reinforced. The air exhaust pump does not require connection to a power source outside the tank, does not have any cables that are difficult to handle, and is highly portable, making it easy to attach to the sealing jig.

[0059] After bonding, the pressure inside the sealing film was released and the sealing jig was removed. Because E258RS has a high viscosity, the FRP reinforcing material did not move even in an uncured state and was able to maintain its position.

[0060] The work took less than 20 minutes, and was so simple that it could be carried out just as easily as work outside the tank.

[0061] The adhesive was then left overnight at room temperature to harden. After the adhesive hardened, the adhesive quality was evaluated and the thickness of the adhesive layer was measured. The adhesive had flowed out from the entire periphery of the bonded FRP reinforcement material, no abnormalities were found in the hammering test, and the peak of the reinforcement target was confirmed with an ultrasonic flaw detector, indicating good adhesive quality. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0062] [Example 2] The reinforcement target was the tank interior floor surface, and the size of the FRP reinforcement material, the surface preparation range, and the pressure reduction range were changed as shown in Table 1. Other than these, reinforcement work was carried out in the same manner as in Example 1. Compared to Example 1, the work time for the surface preparation increased due to the increase in the surface preparation range, but as in Example 1, the work was completed within 20 minutes and the work was simple. After the adhesive hardened, the thickness of the adhesive layer was measured and the adhesive quality was evaluated, and as in Example 1, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0063] [Example 3] Reinforcement was carried out in the same manner as in Example 2, except that the target of reinforcement was the inner wall surface of the tank. As in Example 2, the construction was completed within 20 minutes, and the work was simple. After the adhesive hardened, the thickness of the adhesive layer was measured and the adhesive quality was evaluated. As in Example 2, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully exhibit the reinforcing effect.

[0064] [Example 4] Reinforcement work was carried out in the same manner as in Example 2, except that the target of reinforcement was the ceiling surface inside the tank. Compared to Example 2, the workability of the base preparation was slightly inferior, but the work was completed within 20 minutes and the work was simple. After the adhesive hardened, the thickness of the adhesive layer was measured and the adhesive quality was evaluated, and the results showed good adhesive quality, similar to Example 2. The adhesive layer thickness was also thin enough to fully exhibit the reinforcing effect.

[0065] [Example 5] Reinforcement work was carried out in the same manner as in Example 4, except that E258RW was used as the adhesive. Compared to Example 4, E258RW had a lower viscosity, but the FRP reinforcement was able to maintain its position even after the sealing jig was removed. Work was completed within 20 minutes, making the work simple. After the adhesive hardened, the adhesive layer thickness was measured and the adhesive quality was evaluated. As with Example 4, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0066] [Example 6] As shown in Table 1, the surface preparation area was made smaller than the decompression area, and the magnet of the sealing jig was attached directly to the reinforcement target without a primer layer. Otherwise, the reinforcement was performed in the same manner as in Example 3. Compared to Example 3, the surface preparation area was narrower, which shortened the work time and simplified the process. The work time was within 20 minutes. After the adhesive cured, the adhesive layer thickness was measured and the adhesion quality was evaluated. Compared to Example 3, the magnet installation area was not sufficiently smooth, allowing air to flow into the sealing film from between the film and the reinforcement target. This may have resulted in less decompression within the sealing film, causing the FRP reinforcement to move slightly when the sealing jig was removed, but it was able to maintain its position. After the adhesive cured, the adhesive layer thickness was measured and the adhesion quality was evaluated. The adhesive quality was good. Although the adhesive layer thickness was slightly thicker, it was thick enough to provide a reinforcing effect.

[0067] Example 7 Reinforcement was performed in the same manner as in Example 6, except that the magnet of the sealing jig was greased with HIVAC-G (Shin-Etsu Chemical Co., Ltd.). As in Example 6, the work time was shortened and the work was simple. The work time was within 20 minutes. After the adhesive cured, the thickness of the adhesive layer was measured and the adhesive quality was evaluated. Compared to Example 6, even without forming a primer layer on the surface of the reinforcement target where the magnet would contact, a large amount of air did not flow into the film during decompression, and the decompression amount could be maintained. The FRP reinforcement was able to be pressure-bonded to the reinforcement target with sufficient force, so the FRP reinforcement did not move even when the sealing jig was removed. After the adhesive cured, the thickness of the adhesive layer was measured and the adhesive quality was evaluated. Similar to Example 4, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0068] [Example 8] Reinforcement work was carried out in the same manner as in Example 7, except that the size of the FRP reinforcing material and the surface preparation area were changed as shown in Table 2. Compared to Example 7, the surface preparation area was narrower, which shortened the work time and made the work easier. The work time was within 20 minutes. As in Example 7, a large amount of air did not flow into the film during decompression, the decompression amount could be maintained, and the FRP reinforcing material could be pressed onto the reinforcement target with sufficient force. After the adhesive cured, the adhesive layer thickness was measured and the adhesive quality was evaluated. As in Example 7, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0069] [Example 9] After the FRP reinforcement was temporarily fixed, sealant tape (SM5126 GREY 3.18 mm x 12.7 mm; manufactured by SOLVAY) was placed along the decompression area instead of a sealing jig. A film and vacuum port were attached to cover the reinforcement target, and the target was bagged. Other than these, the reinforcement was performed in the same manner as in Example 3. Compared to Example 3, the work after temporarily fixing the FRP reinforcement took longer, exceeding 20 minutes. However, the work was completed within the usable time of the adhesive, and the work was simple. Furthermore, a sufficient amount of decompression for adhesion was maintained. After the adhesive cured, the adhesive layer thickness was measured and the adhesive quality was evaluated. The results showed good adhesive quality, similar to Example 3. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0070] [Example 10] Reinforcement work was carried out in the same manner as in Example 9, except that the reinforcement target was a 2m x 2m concrete panel. As in Example 9, the work was carried out without any problems, and although the work time exceeded 20 minutes, it was within the usable time of the adhesive, and the work was simple. In addition, a sufficient amount of reduced pressure for adhesion could be maintained. After the adhesive hardened, the thickness of the adhesive layer was measured and the adhesive quality was evaluated, and as in Example 9, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0071] [Example 11] Instead of a sealing jig, sealant tape (SM5126 GREY 3.18 mm x 12.7 mm; manufactured by SOLVAY) was placed along the decompression area, and a film and vacuum port were attached to cover the reinforcement target, followed by bagging. Other than these, reinforcement was performed in the same manner as in Example 6. Compared to Example 6, the work after temporarily attaching the FRP reinforcement took longer, exceeding 20 minutes, but this was within the usable life of the adhesive, and the same decompression amount as in Example 6 could be maintained. After the adhesive cured, the adhesive layer thickness was measured and the adhesive quality was evaluated. The results showed good adhesive quality, similar to Example 6. The adhesive layer thickness was also thin enough to fully demonstrate the reinforcing effect.

[0072] [Example 12] Reinforcement work was carried out in the same manner as in Example 3, except that the size of the FRP reinforcing material, the surface preparation range, and the pressure reduction range were changed as shown in Table 2. Compared to Example 3, the work time associated with the surface preparation increased due to the increased surface preparation range, but the work was completed within 20 minutes, as in Example 3, and the work was simple. After the adhesive hardened, the thickness of the adhesive layer was measured and the adhesive quality was evaluated, and as in Example 3, the adhesive quality was good. The adhesive layer thickness was also thin enough to fully exhibit the reinforcing effect.

[0073]

[0074]

[0075] Comparative Example 1: Reinforcement work was performed in the same manner as in Example 3, except that an electric vacuum pump was used instead of a manual vacuum pump. Because the electric pump was not portable and there was no power source inside the tank, the electric vacuum pump was installed outside the tank, and the tube was pulled into the tank for bonding. However, pulling the long tube into the tank required time and effort to secure it and check its placement route inside the tank, resulting in poor workability. Fixing the tube required difficult handling, and connecting it to the sealing jig took time, making it impossible to achieve crimping within the adhesive's usable time. After the adhesive cured, the adhesive layer thickness was measured and the adhesive quality was evaluated. Because the working time exceeded the adhesive's usable time, the adhesive thickened, making it difficult to press down, and no adhesive flow was observed around the entire circumference of the FRP reinforcement. A tapping test yielded a light sound, but the sound varied depending on the tapping location, resulting in a poor result. Even with an ultrasonic flaw detector, there were scattered areas where the peaks of the reinforcement target could not be detected, indicating poor adhesive quality. The thickness of the adhesive in the area where it was filled was so thick that it was not possible to fully exert the reinforcing effect.

[0076] Comparative Example 2: Reinforcement work was performed in the same manner as in Example 1, except that after the FRP reinforcement material was temporarily fixed, it was manually pressed without using a sealing jig. Compared to Example 1, the bonding process was simpler and the work was completed in a shorter time. However, due to the high viscosity of the adhesive, the adhesive could not be pressed down by hand, and no adhesive flow was observed around the entire periphery of the FRP reinforcement material. After the adhesive cured, the thickness of the adhesive layer was measured and the adhesive quality was evaluated. A tapping test revealed a light sound, and the sound varied depending on the tapping location, resulting in poor adhesion. Even with an ultrasonic flaw detector, there were occasional areas where the peak of the reinforcement target could not be detected, indicating poor adhesion quality. The adhesive layer was thick in the areas filled with adhesive, which was too thick to fully demonstrate the reinforcing effect.

[0077] Comparative Example 3: AUP40T1 adhesive was used, and it was placed in a circular pattern at the center of the area where the primer layer was formed to be reinforced. After the FRP reinforcement was temporarily fixed, it was manually pressed without a sealing jig. Otherwise, the reinforcement was performed in the same manner as in Example 2. Compared to Example 2, the installation was completed in a shorter time, and adhesive flow was observed from the entire periphery of the FRP reinforcement. However, due to the low viscosity of the adhesive and the slight tilt of the floor surface, the FRP reinforcement could not be maintained in position. After the adhesive was released, the FRP reinforcement slid sideways, preventing it from being attached to the intended reinforcement area. After the adhesive cured, the adhesive layer thickness was measured and the adhesive quality was evaluated. The adhesive layer thickness was thin enough to fully demonstrate the reinforcement effect, but a tapping test revealed a soft sound in some areas, possibly due to air bubbles being mixed into the adhesive layer when the FRP reinforcement slid sideways, resulting in a poor result. Even with an ultrasonic flaw detector, it was found that the peaks of the reinforcement targets could not be confirmed in some places, indicating that the adhesive quality was poor.

[0078]

[0079] REFERENCE SIGNS LIST 1 Sealing film 2 Vacuum port 3 Adhesive 4 FRP reinforcement material 5 Frame 6 Magnet 7 Air exhaust pump 8 Reinforcement target 9 Pressure plate 10 Sealant tape

[0080] By using the reinforcement method and sealing jig of the present invention, repair and reinforcement of structures can be carried out easily and quickly even at construction sites where there are many restrictions.

Claims

1. A reinforcing method for attaching and reinforcing an FRP reinforcing material to a reinforcement target with an adhesive, comprising arranging the adhesive and the FRP reinforcing material on the reinforcement target in this order, then sealing the FRP reinforcing material with a sealing film, and using a portable tool to discharge the air inside the sealing film and crimp the FRP reinforcing material to the reinforcement target for attachment.

2. The reinforcing method according to claim 1, wherein the reinforcement target is a steel material, and when sealing, a sealing jig is used which includes at least a magnet, a frame, the sealing film, and a vacuum port and can be fixed to the reinforcement target by the magnet, and the FRP reinforcing material is sealed with the sealing film.

3. The reinforcing method according to claim 2, wherein when sealing, grease is applied between the magnet and the reinforcement target.

4. The reinforcing method according to claim 1 or 2, wherein the portable tool is a non-electric portable tool.

5. A sealing jig used when attaching and reinforcing an FRP reinforcing material to a steel material reinforcement target with an adhesive, comprising at least a magnet, a frame, a sealing film, and a vacuum port, and being fixable to the steel material reinforcement target by the magnet.

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