Concrete reinforcing material and concrete reinforced structure

Abstract

To provide a system for enhancing a bearing force of a concrete skeleton while suppressing increase in at least one of its volume and mass, a concrete reinforced structure is configured to include a skeleton containing concrete having a slit hole linearly formed on a surface layer part of the skeleton; and a concrete reinforcing material having an elongated shape provided to be inserted in the slit hole along a longitudinal direction of the slit hole.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to Japanese Patent Application No. 2024-12122 filed on Jul. 26, 2024, entitled “Concrete Reinforcing Material and Concrete Reinforced Structure.” The entire contents of this application are hereby incorporated herein by reference.BACKGROUND

[0002] The disclosed technology relates to concrete reinforcing materials and concrete reinforced structures.

[0003] Japanese Unexamined Patent Application Publication No. 2012-26238 discloses a reinforcing method for suppressing an occurrence of a crack in a concrete surface layer and for performing a follow-up examination of a crack. In JP 2012-26238 A, a multilayered sheet in which carbon fibers having a latticelike structure are woven in a base material made of a transparent nonwoven fabric is used, as the reinforcement, and this multilayered sheet is fixed on a surface layer of a concrete with a transparent adhesive material. Consequently, it becomes possible to suppress an occurrence of a crack in a concrete and to perform an examination of a crack in a concrete.SUMMARY

[0004] This multilayered sheet has the advantage of being thin while significantly suppressing the increase of the volume of the concrete skeleton, but the deterioration due to the environmental exposures or the fire hazards is remarkable. Therefore, it is desirable to enhance a bearing force of a concrete skeleton without increasing its volume and mass when a bearing force of a concrete is lowered.

[0005] In view of the above-mentioned background, the present disclosure employs, for example, configurations described in the claims.

[0006] According to the present disclosure, a system or mechanism for enhancing a bearing force of a concrete skeleton without increasing at least one of its volume and mass is provided.

[0007] Problems, configurations, and effects other than those described above will be apparent from the following descriptions of embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic view showing a reinforcing material according to one embodiment.

[0009] FIG. 2 (a) to (c) are schematic views showing concrete reinforcing materials according to different embodiments.

[0010] FIG. 3A is a schematic perspective view showing a reinforcing material and a concrete skeleton provided with a slit for inserting the reinforcing material therein, according to one embodiment.

[0011] FIG. 3B is a schematic perspective view showing a concrete reinforced structure according to one embodiment.

[0012] FIG. 4A is a schematic perspective view showing a tunnel made of reinforced concrete.

[0013] FIG. 4B is a schematic perspective view showing a portion of a set of the concrete reinforcing material for reinforcing the tunnel illustrated in FIG. 4A and the tunnel provided with a slit for inserting the concrete reinforcing material.

[0014] FIG. 4C is a schematic perspective view showing a portion of the tunnel provided with the concrete reinforcing material in a slit illustrated in FIG. 4B.

[0015] FIG. 5A illustrates a (a) plan view showing the structure of a slit-hole according to one embodiment, and a (b) cross section along a line b-b.

[0016] FIG. 5 B illustrates a (a) plan view of a concrete reinforced structure that is formed by inserting the concrete reinforcing material in the slit-hole illustrated in FIG. 5A, and a (b) cross section along a line b-b.

[0017] FIG. 6 is a schematic perspective view showing a concrete reinforced structure according to a different embodiment.DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, a concrete reinforced structure, a concrete reinforcing material, and a method for reinforcing a skeleton made of concrete (also referred to concrete skeleton or concrete framework, same hereinafter) according to the present technology will be described with referring to the figures.

[0019] In general, the present technology is provided to form one or a plurality of slit holes on a surface layer of a skeleton (or body) made of concrete, and to reinforce the skeleton made of concrete by inserting one or a plurality of concrete reinforcing materials each having an elasticity along a longitudinal direction, in the slit holes. The concrete reinforced structure obtained in this way is considered to be, for example, reinforced without increasing its mass and volume by comparing to the original concrete skeleton. For example, the concrete reinforcing material is capable of functioning like a reinforcement member (or reinforcing steel member) and easily enhancing a bearing force with respect to the concrete skeleton. In addition, the concrete reinforcing material is made not to be exposed to a surface of the concrete skeleton, and accordingly, this suppresses the degradation thereof.First Embodiment[Concrete reinforcing material] Firstly, a concrete reinforcing material will be described.

[0020] FIG. 1 is a schematic view showing a reinforcing material 100 according to one embodiment. FIG. 2 (a) to (c) are schematic views showing concrete reinforcing materials 100 according to different embodiments.

[0021] A concrete reinforcing material 100 according to the present embodiment is an element for reinforcing a skeleton made of concrete (or skeleton containing concrete or concrete skeleton, for example, please refer to a concrete cube 6 and a concrete skeleton 14 illustrated in FIG. 2). The concrete reinforcing material 100 is typically formed to have an elongated shape, for example, it is formed to have an elongated sheet shape or elongated plate shape. The concrete reinforcing material 100 has an elasticity at least in one direction, typically in the longitudinal direction. For example, the concrete reinforcing material 100 has an elasticity (or tensile elastic modulus) which is higher than that of a concrete skeleton to be repaired. For example, this concrete reinforcing material 100 is capable of functioning as a reinforcement member in a reinforced concrete. From the aforementioned points of view, the concrete reinforcing material 100 may be referred as a reinforcing material or tension member which is capable of applying strength and / or endurance to the concrete skeleton.

[0022] In one embodiment, it is preferable that the concrete reinforcing material 100 has an elasticity which is higher than a required elasticity of the concrete skeleton 14. For example, the elasticity of the concrete reinforcing material 100 is preferably almost equal to or higher than that of the concrete skeleton 14 at the time of manufacturing. As a reference, the tensile elastic modulus of a concrete structure is generally estimated to be almost equal to or somewhat smaller than the compression elastic modulus. The compression elastic modulus (or Young's modulus) of the reinforced concrete is defined in various ways according to the design reference strength, but according to the design reference strength 80, it is defined to be equal to or larger than 3.80×104 N / mm2, and also according to the PHC piles (or Pretensioned Spun High Strength Concrete Piles), it is defined to be equal to or larger than 4.00×104 N / mm2.

[0023] In one embodiment, the concrete reinforcing material 100 includes high-elastic-modulus fibers (or high elasticity fibers). For example, the concrete reinforcing material 100 is a woven fabric made of high-elastic-modulus fibers. For example, as shown in FIG. 1, a woven fabric made of high-elastic-modulus fibers may be provided as a woven fabric including twistless or twisted fiber bundles 1 made up a predetermined number of bundles of high-elastic-modulus fibers (for example, filament yarns) as warps and also including wefts 2 for bundling the warps with each other. The woven fabric made of high-elastic-modulus fibers may be harden by further impregnating a resin material (for example, a thermosetting resin or thermoplastic resin), but this is not required. As illustrated in FIG. 1, for example, the woven fabric made of high-elastic-modulus fibers may be a fiber-reinforced plastic including high-elastic-modulus fibers. It is preferable that a plurality of fiber bundles constituting the warps are tightly connected by use of the wefts without forming a gap between the warps on the whole, in the concrete reinforcing material 100. On the other hand, any weft is available if it is capable of maintaining the connection of a plurality of the fiber bundles, as the weft, and the adjacent wefts may be separated from each other. For example, the wefts may be arranged side by side with an interval in a range of from 1 mm to 20 mm (for example, from 2 mm to 15 mm, or from 3 mm to 10 mm).

[0024] In the present specification, the above-mentioned high-elastic-modulus typically means that the tensile elastic modulus is approximately 100 cN / dtex or more, for example, the tensile elastic modulus is 200 cN / dtex or more, and preferably, it is approximately 353 cN / dtex (400 g / d) or more. The high-elastic-modulus fiber may have the tensile elastic modulus having a value of 353 cN / dtex or more, for example, 500 cN / dtex or more, 700 cN / dtex or more, 900 cN / dtex or more, 1000 cN / dtex or more, or 1200 cN / dtex or more, but are not limited thereto. In addition, each of the fiber bundles constituting the woven fabric may include high-elastic-modulus fibers, for example, having the number of 100 or more, and for example, the number of 10,000 or more. Examples of the high-elastic-modulus fibers include aramid fibers, carbon fibers, high density polyethylene fibers, polybenzazole-based fibers, glass fibers, and the like, but are not limited thereto.

[0025] The tensile elastic modulus may be measured, for example, according to the test methods for chemical fiber tire cords defined in JIS L1017: 2002.

[0026] For example, it is preferable that the concrete reinforcing material 100 has a density lower than that of the concrete skeleton to be reinforced. The density of the concrete skeleton is typically about 2.3 g / cm3 (in a case of the plain concrete), or about 2.45 g / cm3 in a case of the reinforced concrete. On the other hand, for example, the density of the high-elastic-modulus fibers, such as resin fibers or carbon fibers, may be made to be about 2.25 g / cm3 or less, for example, about 2 g / cm3 or less, about 1.9 g / cm3 or less, about 1.8 g / cm3 or less, about 1.6 g / cm3 or less, about 1.5 g / cm3 or less, about 1.4 g / cm3 or less, or about 1.3 g / cm3 or less, and the density of the glass fibers may be, for example, about 2.6 g / cm3 or less. Accordingly, the density of the concrete reinforcing material 100 made of high-elastic-modulus fibers is usually lower than that of the above-mentioned high-elastic-modulus fibers, and the density of the concrete reinforcing material 100 made of a woven fabric of high-elastic-modulus fibers may be even lower. The density of the concrete reinforcing material 100 may be, for example, about 2 g / cm3 or less, about 1.9 g / cm3 or less, about 1.8 g / cm3 or less, about 1.6 g / cm3 or less, about 1.5 g / cm3 or less, about 1.4 g / cm3 or less, about 1.3 g / cm3 or less, about 1.2 g / cm3 or less, or about 1 g / cm3 or less, etc. This makes it possible to reinforce the concrete skeleton of the reinforcing object without excessively increasing its weight.

[0027] Such a concrete reinforcing material may further include a resin which is impregnated into a plurality of fiber bundles. Since the resin is impregnated into a plurality of the fiber bundles, it is possible to integrally collect a plurality of the fiber bundles, and accordingly, it becomes possible to improve the handling thereof at the time of manufacturing, storing, and working at the work site, etc. In addition, since the resin covers the surfaces of a plurality of the fiber bundles, it is possible to suppress deterioration or transformation of the fiber bundles. Accordingly, it is possible to form the woven fabric made of the fiber bundles into a band plate shape or sheet shape.

[0028] The dimensions of the width, the length, and the thickness, etc., of the concrete reinforcing material 100 are not particularly limited. However, in a case where the reinforcement of a skeleton made of a reinforced concrete is performed, it is preferable that the width dimension of the concrete reinforcing material 100 is smaller than the “cover” dimension (for example, covering depth or thickness) of a concrete to be reinforced. From such a point of view, the width dimension of the concrete reinforcing material 100 may be in a range of “the covering depth—1 to 5” mm (or a range of from about a value determined by subtracting 5 mm from the covering depth to about a value determined by subtracting 1 mm from the covering depth). For example, it is preferable that it is formed into a band plate shape or sheet shape having a value in a range of from 20 mm to 100 mm (typically, in a range of from 25 mm to 80 mm).

[0029] In addition, for example, as illustrated in FIG. 2, in the concrete reinforcing materials 100, a plurality of the fiber bundles may be combined (for example, laminated or arranged in layers) in the thickness direction in accordance with the required stress (or reinforcing force). For example, two pieces of one layered reinforcing material having a sheet shape (which corresponds to one layered concrete reinforcing material 100) may be laminated to integrally form the concrete reinforcing material 100 as a (a) two-layered reinforcing material (or tension member) 3, three pieces of one layered reinforcing material may be laminated to integrally form a (b) three-layered reinforcing material (or tension member) 4, or four pieces of one layered reinforcing material may be laminated to integrally form a (c) four-layered reinforcing material (or tension member) 5. Although it is not concretely illustrated in the figures, five or more pieces (for example, 10 pieces, 20 pieces, or 50 pieces) of one layered reinforcing material having a sheet shape may be laminated to integrally form the concrete reinforcing material 100.

[0030] For example, the sheet shaped reinforcing materials which are overlapped each other in the concrete reinforcing materials 100 having such a layered structure may be mutually coupled and integrated by a resin material. In other words, the concrete reinforcing materials 100 having a layered structure may further include a resin material to be impregnated into the respective layers of a plurality of the fiber bundles. If the same resin is impregnated over neighboring layers of the reinforcing materials in the concrete reinforcing materials 100 having a layered structure, it becomes possible to prevent the intervention of a different resin layer (for example, adhesive layer) and accordingly to prevent the occurrence of scaling off of the layers and to suppress reduction in the flexibility (the details will be described later).

[0031] However, according to one embodiment, the concrete reinforcing material 100 having such a layered structure may be coupled by applying a predetermined quantity of an adhesive between the layers of the respective reinforcing materials (for example, woven fabric made of fiber bundles), for example, in a rage where a desired flexibility is realized.

[0032] The resin included in the concrete reinforcing material 100 preferably provide a flexibility to the concrete reinforcing material 100. With respect to the concrete reinforcing material 100, the “flexibility” refers to a property having a softness or flexibility without being damaged when it is folded. In one embodiment, the “flexibility” refers to a property capable of being folded equal to or less than the radius of curvature R 20 m without being damaged when the concrete reinforcing material 100 having the thickness of 1 mm is folded, at normal temperature (for example, at 25° C.). The “flexibility” with respect to the concrete reinforcing material 100 may have any one of the below-mentioned characteristics.

[0033] When the three-point bending test defined in JIS K7171: 2016 is performed with respect to a test piece of a concrete reinforcing material having dimensions of 80 mm, 10 mm, and 4 mm, the flexural modulus thereof is equal to or less than 15 GPa (typically, equal to or less than 10 GPa, equal to or less than 8 GPa, or equal to or less than 5 GPa).

[0034] The concrete reinforcing material 100 having the thickness dimension of 1 cm is capable of being folded (or bended) equal to or less than the radius of curvature R 20 m (for example, equal to or less than 10 m, equal to or less than 5 m, equal to or less than 3 m, equal to or less than 1 m, equal to or less than 50 cm, equal to or less than 30 cm).

[0035] The concrete reinforcing material 100 having the thickness dimension of 1 mm is capable of being folded (or bended) equal to or less than the radius of curvature R 2 m (for example, equal to or less than 1 m, equal to or less than 50 cm, equal to or less than 30 cm, equal to or less than 10 cm, equal to or less than 5 cm, equal to or less than 3 cm).

[0036] Incidentally, the “thickness” of the concrete reinforcing material 100 may be the average thickness of the measured thicknesses at three or more points along the longitudinal direction.

[0037] As such a resin, for example, it is possible to use various types of resin materials capable of realizing the above-mentioned flexibility in a cured state. In addition, it is also possible to use a resin in a liquid condition (resin composition) capable of being impregnated into the above-mentioned fibers or fiber bundles in an uncured state. For example, examples of the resin impregnated in the concrete reinforcing material 100 include a flexible epoxy resin, a urethane resin, a polyester, a polyamide, a polycarbonate, a polypropylene, a polyethersulfone, a triacetylcellulose, a polytetrafluoroethylene, a ThermoPlastic Elastomer (TPE), a Thermoplastic. Vulcanizates (TPV) and the like, each having a flexibility, but are not limited thereto. From points of view of the weather resistant, the environment resistant, and the durability, it is preferable to use a flexible epoxy resin or a urethane resin, among them.

[0038] The resin composition constituting the flexible resin may include, for example, a base polymer, a curing agent, and a modifying agent (or modifier) which contains a flexibility-imparting agent. Incidentally, the flexibility-imparting agent contained in the modifying agent may be included in the base polymer and / or the curing agent, as a form of a functional group, or it may also be included by combining a different modifying function (for example, as a crosslinking agent or the like). The flexibilizing moiety may be contained in any of the base polymer, the curing agent, and / or the flexibilizer. The resin composition may be composed of, but is not limited to, monomers and may be composed of any intermediate reactants. The resin composition may be composed of a resin that has the desired flexibility after curing. A flexible epoxy resin will be described below as an example of the flexible resin. However, a person skilled in the art will understand other flexible resins which are capable of being used in the present technology, by referring to the following descriptions of the flexible epoxy resin.

[0039] An epoxy resin in which a flexible group is introduced may be given as an example of the flexible resin. The epoxy resin composition constituting this epoxy resin may include, for example, an epoxy-based base polymer in an amount of more than 50 wt %. For example, from a point of view of having flexibility, the epoxy-based base polymer may be selected among various species of epoxy compound having two or more epoxy groups in one molecule. The epoxy compound may be a bifunctional epoxy compound having two epoxy groups in one molecule or a polyfunctional epoxy compound having three or more epoxy groups in one molecule. As the epoxy compound, solely one species or a combination of two or more species may be used. In one aspect, an epoxy compound which is liquid at normal temperature (for example, at 25° C.) may be preferably used, from a point of view of operability at a time when it is impregnated into a fiber.

[0040] In one embodiment, examples of the bifunctional epoxy compound may include, but are not limited to, bisphenol A epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins (i.e. epoxy compounds corresponding to that in structure resulting from hydrogenation of bisphenol A epoxy resins to convert aromatic rings to cycloalkyl rings), hydrogenated F epoxy resins, biphenyl epoxy resins, aliphatic epoxy resins (e.g. polypropylene glycol-based epoxy resins, etc.), 1,6-hexanediol diglycidyl ether, and polyethylene glycol diglycidyl ether.

[0041] In one embodiment, examples of the polyfunctional epoxy compound include, but are not limited to, novolac-based epoxy resins, glycidyl amine-based epoxy resins, biphenyl-based epoxy resins, triphenylmethane-based epoxy resins, dicyclopentadiene-based epoxy resins, glycerin-based epoxy resins, trimethylol propane-based epoxy resins, N,N,N′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and polyglycerol polyglycidyl ether. The number of epoxy groups in one molecule of the polyfunctional epoxy compound is at least 3 or greater, may be 4 or greater, or even 5 or greater. The number of epoxy groups in one molecule of the polyfunctional epoxy compound is usually suitably 10 or less, possibly 8 or less, or even 6 or less.

[0042] In some embodiments, as the epoxy compound, a bifunctional epoxy compound may be preferably used. The use of the bifunctional epoxy compound may be advantageous in obtaining a sealant sheet that gives a cured material showing suitable stretchiness. As the bifunctional epoxy compound, solely one species or a combination of two or more species may be used. In one embodiment, as the above-mentioned bifunctional epoxy compound, it is preferable to use an epoxy compound having a five-membered or larger carbon ring structure in the molecule. With a cured product of an impregnated resin formed using a bifunctional epoxy compound having such a structure, the resulting cured material tends to show high strength and good stretchiness. The five-membered or larger carbon ring structure may be, for instance, a benzene ring, naphthalene ring, cyclohexyl ring, etc. Examples of the epoxy compound including such a carbon ring structure include bisphenol A epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, hydrogenated bisphenol F epoxy resins, and biphenyl epoxy resins. In a preferable embodiment, as the bifunctional epoxy compound, a bisphenol F epoxy resin can be used. In a preferred embodiment, bisphenol A epoxy resins may be used as the above-mentioned bifunctional epoxy compound. For example, the bisphenol A liquid epoxy resins may have a weight-average molecular weight (Mw) in a range of from 300 to 600, but is not limited thereto. For example, the weight-average molecular weight may be a value which is determined according to Size Exclusion Chromatography (or SEC) method defined in JIS K7252-1:2016.

[0043] As the above-mentioned epoxy compound, one, two or more species of polyfunctional epoxy compound may be used in combination with a bifunctional epoxy compound or in place of the bifunctional epoxy resin. The use of a polyfunctional epoxy resin may increase the strength of the cured material. The combined use of a bifunctional epoxy compound and a polyfunctional epoxy compound may bring about an impregnated resin that provides a cured material that combines strength and stretchiness at a high level. In some embodiments, as the polyfunctional epoxy compound, it is possible to use a polyfunctional epoxy compound having an epoxy group-containing repeat unit (i.e. a polyfunctional epoxy polymer) and it is preferable to use, for instance, a novolac-based epoxy resin. Examples of the novolac-based epoxy resin include phenol novolac-based epoxy resins and o-cresol novolac-based epoxy resins. The use of a novolac-based epoxy resin may be advantageous in obtaining a sealant sheet that gives a cured material with high strength and good stretchiness. With the use of a novolac-based epoxy resin having a lower molecular weight, the stretchiness of the cured material tends to increase. For instance, it is preferable to use a phenol novolac-based epoxy resin that exists as liquid at room temperature.

[0044] Examples of the above-mentioned epoxy compounds include, but are not limited to, the product names of “EPICLON”, manufactured by DIC Co., Ltd, 840 to 850 series, TSR-960, 601, 1650-75MPX, EXA-4850 series, and the like; “jER (R)” which is a flexible type epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd, 871, 872, 872X75, 825, 827, 828, etc.; EPOLEAD GT401 etc., manufactured by Daicel Co., Ltd.; a flexible type epoxy resin, manufactured by Konishi Co., Ltd., QUICK 5, BOND E series, primers for microcrack repair, etc.

[0045] The epoxy resin composition may include, for example, a flexibility-imparting agent, a crosslinking agent, a curing accelerator, and the like, as the modifying agent.

[0046] As the flexibility-imparting agent, it is possible to use an element capable of imparting a flexibility to a cured material of a base polymer, for example, a compound capable of imparting a flexibility to an epoxy resin by adding a modifier or by introducing a flexible skeleton. Examples of the flexibility-imparting agent include alkylene ether-based compounds represented by a polyglycol diglycidyl ether (DGEPG) and the like; chain (non-cyclic) polycarboxylic acid anhydrides (long-chain fatty acid compounds) formed by polycondensation of polycarboxylic acids, represented by a polyazelaic acid anhydride or a polysebacic acid anhydride; aromatic compounds represented by a bisphenol A (BPA); liquid rubbers with a functional group at a terminal, represented by a carboxyl group-terminated polybutadiene nitrile rubber (CTBN); and silicone compounds represented by a modified silicone oil, etc., but are not limited thereto.

[0047] Examples of the crosslinking agent include: bisphenol A; epichlorohydrin type epoxy resin; ethyleneglycidylether; polyethylene glycol diglycidyl ether; glycerin diglycidyl ether; glycerin triglycidyl ether; 1,6-hexanediol glycidyl ether; trimethylolpropane triglycidyl ether; diglycidyl aniline; diamine glycidyl amine; N,N,N′,N′-tetraglycidyl-m-xylylenediamine; and 1,3-bis(N,N′-diamine glycidyl aminomethyl) cyclohexane, etc., but are not limited thereto. For the crosslinking agent, solely one species or a combination of two or more species may be used. In one embodiment, a bifunctional crosslinking agent having two crosslinking reactive groups (for example, ethylenically unsaturated groups, isocyanate groups, etc.) per molecule is used as at least one part of the crosslinking agent. The use of a bifunctional crosslinking agent facilitates the formation of a flexible crosslinked structure. For the bifunctional crosslinking agent, solely one species or a combination of two or more species may be used. Examples of the bifunctional crosslinking agents include bifunctional monomers such as a bifunctional (meth) acrylate, and a bifunctional isocyanate compound, etc. The bifunctional crosslinking agent may be used in combination with a tri- or polyfunctional crosslinking agent. Examples of the product name of the epoxy-based cross-linking agent include the product name of “TETRAD-X” and “TETRAD-C”, manufactured by Mitsubishi Gas Chemical Co., Ltd., the product name of “EPICLON CR-5L”, manufactured by DIC Co., Ltd., the product name of “DENACOL EX-512”, manufactured by Nagase ChemteX Co., Ltd., and the product name of “TEPIC-G”, manufactured by Nissan Chemical Industry Co., Ltd.

[0048] As the curing agent, it is possible to use a known or conventional curing agent (including, for example, a thermal polymerization initiator or a photopolymerization initiator) as a single kind or in combination of two or more kinds according to the base polymer, etc., to be used, as appropriate. As the epoxy curing agent, for example, it is possible to use a phenol-based curing agent, an amide-based curing agent, an amine-based curing agent, imidazoles, an acid anhydride-based curing agent, and an organic phosphine, as the polymerization initiator. In one embodiment, examples of the curing agent include a tertiary amine, a m-xylylenediamine and a modified aliphatic polyamine.

[0049] The epoxy compound used in the present embodiment was a bisphenol A-type liquid epoxy resin which was a polycondensate of 4,4′-isopropylidenediphenol and 1-chloro-2,3-epoxypropane in which a resin composition mixed with a polyamine-based curing agent in a mass ratio in a range of approximately from 1:1 to 10:1 was used, but the embodiment is not limited thereto. The mixed viscosity of the above-mentioned resin composition was approximately 200 mPa s or less at normal temperature, and the curing time was approximately 35 minutes (at 25° C.). With respect to a cured material as a single substance, for example, the epoxy compound is adjusted so as to fulfill any one or more of the following conditions of the compressive strength of 30 N / mm2 or more (for example, 50 N / mm2 or more, or 70 N / mm2 or more), the tensile shear adhesive strength of 10 N / mm2 or more (for example, 15 N / mm2 or more), the flexural strength of 35 N / mm2 or more (for example, 50 N / mm2 or more, or 70 N / mm2 or more), and the tensile adhesive strength of 1.6 N / mm2 or more (for example, 2 N / mm2 or more).

[0050] For example, from a point of view of enhancing the handling, the resin included in the concrete reinforcing material 100 according to one embodiment may be made to have a ratio of about 100 g or more, 200 g or more, 300 g or more, or 400 g or more, per one m2 of the fiber bundle and / or fiber woven fabric. Also, from a point of view of suitably exhibiting the flexibility, it may be made to have a rate of approximately 1,000 g or less, 800 g or less, or 600 g or less, per one m2 of the fiber bundle and / or fiber woven fabric. Also, with respect to the resin included in the concrete reinforcing material 100 having a layered structure according to one embodiment, for example, from a point of view of enhancing the handling, it may be made to have a rate of approximately 100 g or more, 300 g or more, 500 g or more, 700 g or more, or 900 g or more, per one kg of the fiber bundle and / or fiber woven fabric. Also, from a point of view of suitably exhibiting the flexibility, it may be made to have a rate of approximately 1,500 g or less, 1,200 g or less, or 1,000 g or less, per one kg of the fiber bundle and / or fiber woven fabric. With respect to the impregnation of the resin to the fiber bundle and / or fiber woven fabric, for example, it is possible to use the injection, atmospheric pressure impregnation, vacuum impregnation, vacuum pressure impregnation, or the like.

[0051] As described above, for example, the concrete reinforcing material 100 is made to have both tensile elasticity and flexibility so that it is possible to realize a reinforcing material which is excellent in the handleability at a time of the manufacturing, the storing, and the performing the construction at the work site. The concrete reinforcing material 100 according to the present technology may be provided, for example, with a flexibility to be wound on a roll. Also, the concrete reinforcing material 100 according to the present technology may be provided, for example, as a reinforcing material capable of being constructed to a curved surface such as a tunnel. In addition, the concrete reinforcing material 100 according to the present technology may be made to be performed the bending thereof, for example, to a reinforcing steel at the work site, by hand, and, for example, it may easily enhance the fixing force.[Method for Reinforcing a Concrete Skeleton]

[0052] Subsequently, a way of reinforcing a concrete skeleton by use of the concrete reinforcing material 100 will be described.

[0053] In general, the method for reinforcing a concrete skeleton according to the present technology includes the following steps of:

[0054] (1) forming a slit hole linearly on a surface layer part of a skeleton made of concrete, and

[0055] (2) inserting a concrete reinforcing material having an elongated shape, into the slit hole, to be aligned with an extending direction of the slit hole.[1. Step of Forming a Slit Hole]

[0056] FIG. 3A is a schematic perspective view illustrating the concrete reinforcing materials 100 and the concrete cube 6 (which is one example of the concrete skeleton) to be reinforced, according to one embodiment.

[0057] The concrete cube 6 to be reinforced is mainly constituted of concrete. The concrete cube 6 may be constituted of reinforced concrete in which one or a plurality of reinforcing steels are disposed. Alternatively, the concrete cube 6 may be constituted of concrete in which no reinforcing steel is disposed. For example, the concrete cube 6 according to the present embodiment is constituted of a concrete mass having a cubic shape (without a reinforcement) in which no reinforcing steel is disposed.

[0058] At the step of forming a slit hole, one or a plurality of slit holes 8, 9, 10 for inserting the concrete reinforcing material 100 are formed with respect to the concrete cube 6. Each of the slit holes 8, 9, 10 is preferably formed along a direction in which the tensile strength of the concrete reinforcing material 100 is desired to be increased. For example, one or a plurality of the slit holes 8, 9, 10 may be formed on a single skeleton. For example, two or more of the slit holes 8, 9, 10 may be formed on the same surface or different surfaces of a single skeleton. For example, a plurality of the slit holes 8, 9, 10 may be formed along the same direction or different directions with each other. In addition, each of the slit holes 8, 9, 10 may be formed to have a shape suitable to insert the concrete reinforcing material 100 having a shape which is suitable to apply a desired bearing strength to the concrete cube 6. For example, the slit holes 8, 9, 10 may be formed in a linear shape or curved shape on a surface layer part of the concrete cube 6.

[0059] In the embodiment illustrated in the FIG. 3A, a slit hole 8 on a top surface, a slit hole 9 on a side surface, and a slit hole 10 on a bottom surface are formed on the top surface, the front surface and the bottom surface of the concrete cube 6, respectively. Each of the slit hole 8 on the top surface and the slit hole 10 on the bottom surface is formed in a linear shape along the X-axis direction of the concrete cube 6, and the slit hole 9 on the side surface is formed in a linear shape along the Z-axis direction of the concrete cube 6. By making the slit holes 8, 9, 10 straight, the tensile strength in the direction along the straight line may be effectively increased. In addition, by separately forming the slit holes along the X-axis direction on the top surface and the bottom surface of the concrete cube 6, the tensile strength of the concrete cube 6 along the X-axis direction may be increased without causing unevenness as a whole.

[0060] Each of the concrete reinforcing materials 100a, 100b, 100c used in the present embodiment is made of filament threads having high tensile elastic modulus, and is formed to have a band plate shape (or plate shape) or tape shape having a substantially rectangular cross-section. The density of the concrete reinforcing materials 100a, 100b, 100c is equal to or less than about 1.2 g / cm3. Each of the respective slit holes 8, 9, 10 may be formed to have a dimension for accommodating the concrete reinforcing material 100 without projecting it therefrom. For example, each of the slit holes 8, 9, 10 may be formed to have a shape and a size corresponding to the concrete reinforcing material 100 so that the concrete reinforcing material 100 is capable of being fitted into it without play. Alternatively, each of the slit holes 8, 9, 10 may be formed to have a shape and a size slightly larger than the concrete reinforcing material 100 so that the concrete reinforcing material 100 is capable of being smoothly inserted into it.

[0061] In one embodiment, each of the slit-holes 8, 9, 10 may preferably have a groove having an approximately rectangular cross section, and the dimension in the width direction may be, for example, a sum of the thickness dimension of the concrete reinforcing material 100a, 100b, 100c to be inserted and a predetermined clearance. The clearance is designed, for example, as a dimension obtained by adding a size of a gap which is in a range of from 0.1 mm to 1 mm to both sides of the concrete reinforcing material 100a, 100b, 100c (or facing inner walls of the slit hole are separated from the concrete reinforcing material by a clearance in a range of from 0.1 mm to 1 mm). In addition, the dimension in the depth direction of the slit-holes 8, 9, 10 may be, for example, a dimension corresponding to the dimension in the width direction of the concrete reinforcing material 100a, 100b, 100c.

[0062] In this way, the slit holes 8, 9, 10 may be formed so that the dimension in the depth direction is made to be larger than the dimension in the width direction. For example, the slit holes 8, 9, 10 may be formed (for example, by grooving) by use of the grinder (for example, a grinding machine for free grinding). The grinder is also referred to as, for example, a grooving cutter. Accordingly, it is possible to increase the bonded area between the concrete cube 6 and the concrete reinforcing material 100a, 100b, 100c and also decrease the area where the respective concrete reinforcing materials 100a, 100b, 100c are exposed to the external environment. As a consequence, it becomes possible to effectively improve the bearing force of the concrete cube 6 and also suppress the deterioration in the concrete reinforcing materials 100a, 100b, 100c due to the environmental exposures.[2. Step of Inserting a Concrete Reinforcing Material]

[0063] FIG. 3B is a schematic perspective view showing the concrete reinforced structure 200 according to one embodiment.

[0064] At the step of inserting the concrete reinforcing material, the concrete reinforcing materials 100a, 100b, 100c are inserted into the slit-holes 8, 9, 10 of the concrete cube 6.

[0065] As the concrete reinforcing materials 100a, 100b, 100c, for example, materials each having a dimension corresponding to the longitudinal dimension of each of the slit holes 8, 9, 10 may be used. The concrete reinforcing materials 100a, 100b, 100c may be inserted into the slit holes 8, 9, 10, for example, after an adhesive is applied to each surface of the concrete reinforcing materials 100a, 100b, 100c. Then, the concrete reinforcing materials 100a, 100b, 100c are inserted into the slit holes 8, 9, 10 and the adhesive is made to be cured. Incidentally, the concrete reinforcing materials 100a, 100b, 100c may be inserted into the slit holes 8, 9, 10 after an adhesive is applied or filled into each of the slit holes 8, 9, 10. As the adhesive, for example, a resin material (for example, a thermosetting resin or thermoplastic resin) may be used.

[0066] In order to suitably apply the tensile force (or tension force) of the concrete reinforcing material 100a, 100b, 100c to the concrete cube 6, it is preferable that the adhesive has a higher adhesive force (or sticking force) with respect to the concrete. The adhesive strength of the adhesive after being cured may be, for example, defined as the tensile shear adhesive strength of 1 N / mm2 or more, preferably, 3 N / mm2 or more, 5 N / mm2 or more, or 10 N / mm2 or more, when measured in accordance with JIS K6850:1999. In this case, the adherend may be, for example, given as a surface of a concrete according to a standard formulation, based on the standard specifications for concrete structures, or a cutting surface made by a grinder. In addition, from a point of view of firmly fixing the concrete reinforcing material 100 to the slit hole, it is desirable that the adhesive has a high hardness. For example, the hardness of the adhesive after being cured may be defined as the durometer hardness (HDD) of 60 or more, preferably, 70 or more, or 80 or more, when measured in accordance with JIS K7215:1986. Examples of the adhesive for fixing the above-mentioned concrete reinforcing material 100 may include a thermosetting epoxy resin, a saturated polyester resin, a thermoplastic polyamide resin, a polycarbonate resin, and the like, but are not limited thereto.

[0067] Preferably, as the adhesive for fixing the concrete reinforcing material 100 to the slit hole, it is possible to use a material that satisfies a high adhesive strength and has a good adhesiveness (for example, compatibility) with the resin included in the concrete reinforcing material 100. From this point of view, for example, it is possible to use an adhesive made of an epoxy-based resin when the resin included in the concrete reinforcing material 100 is an epoxy resin. As one example of such an epoxy-based resin, an epoxy resin-based adhesive (for example, Bond E series manufactured by Konishi Co., Ltd.) may be given.

[0068] By curing the adhesive, the concrete reinforcing materials 100a, 100b, 100c are integrated with the concrete cube 6 inside the slit-holes 8, 9, 10, and accordingly, the concrete reinforced structure 200 is obtained. Incidentally, the concrete reinforcing materials 100a, 100b, 100c may be more firmly fixed to the concrete cube 6 by using an adhesive made of the same resin material that is impregnated in the concrete reinforcing materials 100a, 100b, 100c, or an adhesive made of a resin material compatible with the resin material that is impregnated in the concrete reinforcing materials 100a, 100b, 100c, as the adhesive.

[0069] By the above configuration, it is possible to apply a tensile force to the concrete cube 6 by fitting the concrete reinforcing materials 100a, 100b, 100c (or tensioning members) into the slit holes 8, 9, 10 of the concrete cube 6, and accordingly, it becomes possible to easily reinforce the concrete cube 6. Also, the concrete reinforcing materials 100a, 100b, 100c are accommodated in the slit holes 8, 9, 10 of the concrete cube 6. Therefore, it becomes possible to suppress the degradation of the concrete reinforcing materials 100a, 100b, 100c and reinforce the concrete cube 6 without increasing its volume. In addition, the density of the concrete reinforcing materials 100a, 100b, 100c is lower than that of the concrete cube 6 so that it is possible to reinforce the concrete cube 6 without increasing its weight before and after the repair. Furthermore, it is possible to reinforce the concrete cube 6 without impairing the appearance thereof.

[0070] According to the concrete reinforced structure 200 obtained in this way, the concrete reinforcing materials 100a, 100b, 100c impart a bearing force against a tension, to the concrete that is resistant to compression. For example, the concrete reinforcing materials 100a, 100b, 100c may impart the same or similar bearing force and tensile force thereto as those of the conventional reinforcing steel. Therefore, by using the above-mentioned concrete reinforcing materials 100a, 100b, 100c, it is possible to obtain the concrete reinforced structure 200 having more enhanced bearing force against compressive and tensile forces, by omitting, for example, the reinforcement work, the form construction work, and the concrete placement work. This is advantageous in that the cost and the construction period may be reduced by half.Second Embodiment

[0071] FIG. 4A is a schematic perspective view showing a tunnel provided as a concrete reinforced structure 200 according to one embodiment. FIG. 4A shows a cross-section of a part of the tunnel to facilitate the understanding. FIG. 4B is a partial perspective view showing a tunnel which is formed of reinforced concrete (which is an example of a concrete skeleton) during the period of the reinforcement, showing an enlarged part of a part illustrated by a circle in FIG. 4A. FIG. 4C is a partial perspective view showing a reinforcement structure of the tunnel, showing an enlarged part of a part illustrated by a circle in FIG. 4A.

[0072] In the present embodiment, the same configurations, operations and effects as those of the first embodiment may not be described in detail.

[0073] This tunnel is formed as a curved surface body 7 made of concrete having a substantially semi-cylindrical shape. In FIG. 4A to 4C, the X axis, the Y axis, and the Z axis correspond to the radial direction, the extending direction, and the up-down direction of the tunnel, respectively. In the present embodiment, the tunnel is reinforced along the Y-axis direction and the circumferential direction. For the reinforcement, concrete reinforcing materials 100d, 100e each made of a woven fabric of fiber bundles, and a gap filling member (or fill member or filler) 13 are used. Each of the concrete reinforcing materials 100d, 100e and the gap filling member 13 used in the present embodiment is formed into a band plate shape or tape shape each having substantially the same width-dimension and thickness-dimension.[1. Step of Forming a Slit Hole]

[0074] Firstly, at the step of forming a slit hole, as illustrated in FIG. 4B, slit holes 11, 12 are formed from the inside of the tunnel, with respect to the curved surface body 7 made of concrete. For example, firstly, a slit hole 11 (which is an example of a first slit hole) is formed along the extending direction (or Y-axis direction) of the tunnel, and then a slit hole 12 (which is an example of a second slit hole) is formed along the circumferential direction. In FIG. 4B, only one slit hole 11 extending along the extending direction of the tunnel is illustrated to be provided on the top part of the tunnel. However, the slit hole 11 extending along the extending direction may be formed not only at the top part of the tunnel, but also at a plurality of positions in the circumferential direction. Similarly, the slit holes 12 extending along the circumferential direction may also be formed at a plurality of positions in the extending direction of the tunnel. The slit hole 11 and the slit hole 12 intersect with each other when viewed in the Z-axis direction and communicate with each other.

[0075] The dimension of the slit hole 11 and the slit hole 12 in the width direction correspond to the dimension of the concrete reinforcing material 100d, 100e and the gap filling member 13 in the thickness direction. The depth of the slit hole 12 corresponds to the dimension of the concrete reinforcing material 100e in the width direction. The depth of the slit-hole 11 corresponds to the sum of the dimensions of the concrete reinforcing material 100d and the concrete reinforcing material 100e (or the gap filling member 13) in the width direction. The depth dimensions of the slit hole 11 and the slit hole 12 are larger than the dimensions in the width direction. However, it is desirable that the depth of the slit hole 11 is provided at a surface layer of the concrete skeleton (that is, at a part of the so-called “concrete cover” in which no reinforcing steel is disposed). In other words, the slit hole 11 preferably has the dimension in the depth direction so as to be equal to or smaller than the covering depth of the reinforced concrete. Accordingly, it is possible to carry out the construction work without damaging the reinforcing steel.[2. Step of Inserting]

[0076] Subsequently, at the step of inserting, firstly, the concrete reinforcing material 100d (which is an example of the first concrete reinforcing material) is inserted into the slit hole 11, and the concrete reinforcing material 100e (which is an example of the second concrete reinforcing material) is inserted into the slit hole 12. At this time, for example, the concrete reinforcing materials 100d, 100e may be preferably inserted (or fitted) in the slit-holes 11, 12 after a predetermined quantity of an adhesive is applied or filled to each of the slit-holes 11, 12. In addition, the slit hole 11 is made to be deep with respect to the concrete reinforcing material 100d so that it is possible to push the concrete reinforcing material 100d to a predetermined position in the depth of the slit hole 11 after the concrete reinforcing material 100d is inserted into the slit hole 11 and then the gap filling member 13 is further fitted into the slit hole 11. Since the concrete reinforcing material 100e is a woven fabric of fiber bundles formed into a band plate shape or tape shape, it is possible to easily deform it into an arc shape along the surface of the curved surface body 7 for inserting the same.

[0077] Incidentally, the gap filling member 13 may not be necessarily required. However, the gap filling member 13 is useful for pushing the concrete reinforcing material 100d to a predetermined position in the depth of the slit hole 11, for preventing the concrete reinforcing material 100d from being exposed to the atmosphere, and for enhancing the aesthetic appearance of the surface of the concrete curved surface body 7 after being repaired. In addition, it is possible to suppress the degradation of the concrete reinforcing material 100d due to the environmental exposures, the fire hazards, and the like. For example, as illustrated in FIG. 4C, after the adhesive is cured, it is possible to obtain the concrete reinforced structure 200 which is reinforced by the concrete reinforcing materials 100d, 100e.

[0078] With the above configuration, the concrete reinforcing material 100d and the concrete reinforcing material 100e are disposed in the slit-holes 11, 12 in a state of being twisted and / or crossed with each other. This increases the tensile strength of the concrete reinforced structure 200 with respect to the direction in which the concrete reinforcing material 100d extends and to the direction in which the concrete reinforcing material 100e extends. Accordingly, it is possible to reinforce the concrete skeleton in desired directions.

[0079] If a long period of time elapses, concrete skeletons such as tunnels may be superannuated, and cracks may be generated in the concrete or rust may be generated in the reinforcing steel, and as a result, strength (or tension) of the concrete skeletons may be remarkably lowered. Even in such a case, by use of the above-mentioned method, it is possible to reinforce the concrete skeleton without increasing its mass and volume and also without significantly changing its appearance.Third Embodiment

[0080] FIG. 5A illustrates a (a) plan view showing the structure of the slit holes 15, 16 for inserting the concrete reinforcing materials, and a (b) cross section along a line b-b. In addition, FIG. 5B illustrates a (a) plan view showing the concrete reinforced structure 200 in which concrete reinforcing materials 100g, 100f are inserted into the slit-holes 15, 16, and a (b) cross section along a line b-b.

[0081] In the present embodiment, the same configurations, operations and effects as those of the first and second embodiments may not be described in detail.[1. Step of Forming a Slit Hole]

[0082] For example, in a case where the concrete skeleton to be reinforced is a large-sized structure (for example, a structure such as a tunnel or a building), it is not desirable to prepare a concrete reinforcement material having the same length as the dimension of the concrete skeleton in the reinforcing direction, from points of view of the manufacturing, the managing / storing, the transporting, and the performing the construction at the work site, etc. Accordingly, it is preferable that when a large-sized skeleton made of concrete is reinforced, for example, a concrete reinforcing material 100 having a dimension easy to handle is connected and used.

[0083] In such a case, at the step of forming a slit hole, for example, as illustrated in FIG. 5A, with respect to the concrete 14, the first slit hole 15 and the second slit hole 16 are preferably formed to be extended along the reinforcing direction and to be adjacent to each other only in a predetermined dimension 17. For example, the first slit hole 15 and the second slit hole 16 are substantially parallel to each other and communicate with each other at the adjacent part. For example, such a slit may be formed, at first, by forming a first slit hole 15 by using a grinder (for example, a grinding machine for free grinding) 20 which is set to a predetermined cutting groove width, then by moving (or offsetting) the grinder 20 in the width direction by the width of the groove and by forming a second silt hole 16. At this time, the second slit hole 16 is preferably formed such that one end of the first slit hole 15 and the other end of the second slit hole 16 are adjacent to each other by the predetermined dimension 17.[2. Step of Inserting]

[0084] Subsequently, at the step of inserting, as illustrated in FIG. 5B, for example, a first concrete reinforcing material 100f is inserted into the first slit hole 15, and a second concrete reinforcing material 100g is inserted into the second slit hole 12. At this time, it is preferable that the concrete reinforcing materials 100f, 100g are inserted therein, for example, after applying or filling a predetermined quantity of an adhesive 19 to each of the slit holes 11, 12. In addition, it is preferable that one end of the first concrete reinforcing material 100f and the other end of the second concrete reinforcing material 100g are fitted in the slit holes 11, 12 so as to be adjacent to each other by a predetermined dimension 18. In the example illustrated in FIGS. 5A and 5B, the dimension 18 is significantly smaller than the dimension 17, but the dimension 17 and the dimension 18 may be generally the same.

[0085] In addition, a layer of an adhesive 19 exists between the first concrete reinforcing material 100f and the second concrete reinforcing material 100g. The first concrete reinforcing material 100f and the second concrete reinforcing material 100g are connected with the predetermined dimension 18 through the layer of the adhesive 19. Accordingly, the concrete 14 may be continuously reinforced by the first concrete reinforcing material 100f and the second concrete reinforcing material 100g.

[0086] In the example illustrated in FIG. 5B, the layer of the adhesive 19 has a sufficient thickness, but the layer of the adhesive 19 may have a thickness of about a clearance. Alternatively, at least a part or all of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be in contact with each other in the area indicated by the dimension 18. In this case, the second slit hole may be offset from the first slit hole 15 by a dimension narrower than the groove width. Accordingly, the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be more firmly connected with each other.

[0087] In the present embodiment, the first slit hole 15 and the second slit hole are made to be parallel to each other, but as long as they are continuous with the predetermined dimension 17, they need not necessarily be parallel to each other. In addition, the first concrete reinforcing material 100f and the second concrete reinforcing material 100g are also made to be parallel to each other, but as long as they are continuous with the predetermined dimension 18, they need not necessarily be parallel to each other. It is preferable that the dimension 17 of the communicating part of the first slit hole 15 and the second slit hole may be, for example, in a range of from 250 mm to 300 mm, but not limited to this. Also, it is preferable that the dimension 18 of the connecting part of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be in a range of from 200 mm to 250 mm, but not limited to this. Accordingly, the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be easily and firmly coupled.

[0088] As the grinder 20, for example, it is possible to use an adjustable grooving grinder provided with grinding teeth of which groove width is capable of freely being adjusted. In addition, it is possible to make the first slit hole 15 and the second slit hole deeper than the widths of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g so as to cover the surfaces of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g with the adhesive 19 after being inserted into the first slit hole 15 and the second slit hole, respectively, in order to seal them with air-tightness and fluid-tightness. Alternatively, it is also possible to dispose gap filling members at the surfaces of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g so as to cover the first concrete reinforcing material 100f and the second concrete reinforcing material 100g, respectively.Fourth Embodiment

[0089] FIG. 6 is a schematic perspective view showing a concrete reinforced structure 200 according to one embodiment. In the concrete reinforced structure 200 of the present embodiment, at least one end of the concrete reinforcing material 100 is bent. The same configurations, operations and effects as those of the first, second and third embodiments may not be described in detail.

[0090] According to the present embodiment, at the step of forming a slit hole, at least one end (in this example, both ends) of the slit hole is bent in the concrete skeleton to be reinforced. For example, the form of the bending may be decided as with the case of the bending method of a reinforcing steel. In one example, it may be bent along a nearly U-shape with respect to the slit hole extending in the longitudinal direction, for example, so as to be inclined at an angle of 90 degrees, 135 degrees, or 180 degrees. At the time, for example, it is possible to adapt a bend inside radius for the case of utilizing a reinforcing steel corresponding to the tensile elastic modulus of the concrete reinforcing material 100, as the bend inside radius of the bending portion. Here, it is bent with a radius of curvature of approximately 5 cm. However, when forming the slit hole by using a grinder is difficult, at least one end of the slit hole may be inclined in a direction crossing the longitudinal direction (or extending direction) of the slit hole.

[0091] Subsequently, at the step of inserting, the concrete reinforcing material 100 on which an adhesive is applied is inserted into the formed slit hole. For example, the concrete reinforcing material 100 according to the present embodiment is made to have a band plate shape having a length of about 200 m, and is maintained while being wound on a roll (e.g., about 10 cm in diameter at the core). Accordingly, at the step of inserting, the concrete reinforcing material 100 is fed out and cut at a predetermined length at the work site, and then inserted into the slit hole while being bent in accordance with the slit hole. The end of the concrete reinforcing material 100 is bent with a radius of curvature of approximately 5 cm to match the slit hole. As the adhesive, for example, it is possible to use an epoxy resin. Then, when the adhesive is cured, the concrete reinforced structure 200 related to the present technology may be obtained.

[0092] At least one end (in this example, both ends) of the concrete reinforcing material 100 is bent in the concrete reinforced structure 200. Accordingly, for example, if the concrete skeleton is expanded, a tensile force (or tension force) is generated along the concrete reinforcing material 100 in the concrete reinforced structure 200. At the time, since at least one end (in this example, both ends) of the concrete reinforcing material 100 is bent, the fixing force with respect to the concrete skeleton is enhanced. Accordingly, it is possible to effectively reinforce the concrete skeleton.

[0093] The present disclosure is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for the purpose of clearly illustrating the present disclosure, and are not necessarily limited to those having all the described configurations. In addition, a part of a configuration of one embodiment may be replaced with a configuration of different embodiment, and a configuration of one embodiment may be added to a configuration of different embodiment. Further, it is possible to add, delete, or replace a part of a configuration of each embodiment with other configuration. The present disclosure discloses any one or any combination of two or more of the features recited in the claims.EXPLANATION OF REFERENCE NUMERALS1 . . . Fiber bundle,

[0095] 2 . . . Wefts,

[0096] 3 . . . Two-layered tension member,

[0097] 4 . . . Three-layered tension member,

[0098] 5 . . . Four-layered tension member,

[0099] 6 . . . Concrete cube,

[0100] 7 . . . Concrete curved surface body,

[0101] 7a . . . Enlargement of the concrete curved surface body,

[0102] 8 . . . Slit hole on a top surface,

[0103] 9 . . . Slit hole on a side surface,

[0104] 10 . . . Slit hole on a bottom surface,

[0105] 11 . . . Slit hole along y direction,

[0106] 12 . . . Slit hole along x direction,

[0107] 13 . . . Gap filling member (or fill member or filler),

[0108] 14 . . . Concrete (or concrete skeleton),

[0109] 15 . . . Slit hole along l direction,

[0110] 16 . . . Slit hole along r direction,

[0111] 17 . . . Dimension of a slit hole,

[0112] 18 . . . Dimension of a tension member,

[0113] 19 . . . Adhesive,

[0114] 20 . . . Grinder (or grinding machine for free grinding).

[0115] 100 . . . Concrete reinforcing material (or tension member),

[0116] 100a . . . . Tension member on a top surface,

[0117] 100b . . . . Tension member on a side surface,

[0118] 100c . . . . Tension member on a bottom surface,

[0119] 100d . . . . Tension member along Y direction,

[0120] 100e . . . . Tension member along X direction,

[0121] 100f . . . . Tension member along L direction,

[0122] 100g . . . . Tension member along R direction,

[0123] 200 . . . Concrete reinforced structure,

Examples

first embodiment

[Concrete reinforcing material] Firstly, a concrete reinforcing material will be described.

[0020]FIG. 1 is a schematic view showing a reinforcing material 100 according to one embodiment. FIG. 2 (a) to (c) are schematic views showing concrete reinforcing materials 100 according to different embodiments.

[0021]A concrete reinforcing material 100 according to the present embodiment is an element for reinforcing a skeleton made of concrete (or skeleton containing concrete or concrete skeleton, for example, please refer to a concrete cube 6 and a concrete skeleton 14 illustrated in FIG. 2). The concrete reinforcing material 100 is typically formed to have an elongated shape, for example, it is formed to have an elongated sheet shape or elongated plate shape. The concrete reinforcing material 100 has an elasticity at least in one direction, typically in the longitudinal direction. For example, the concrete reinforcing material 100 has an elasticity (or tensile elastic modulus) which is hi...

second embodiment

[0071]FIG. 4A is a schematic perspective view showing a tunnel provided as a concrete reinforced structure 200 according to one embodiment. FIG. 4A shows a cross-section of a part of the tunnel to facilitate the understanding. FIG. 4B is a partial perspective view showing a tunnel which is formed of reinforced concrete (which is an example of a concrete skeleton) during the period of the reinforcement, showing an enlarged part of a part illustrated by a circle in FIG. 4A. FIG. 4C is a partial perspective view showing a reinforcement structure of the tunnel, showing an enlarged part of a part illustrated by a circle in FIG. 4A.

[0072]In the present embodiment, the same configurations, operations and effects as those of the first embodiment may not be described in detail.

[0073]This tunnel is formed as a curved surface body 7 made of concrete having a substantially semi-cylindrical shape. In FIG. 4A to 4C, the X axis, the Y axis, and the Z axis correspond to the radial direction, the ex...

third embodiment

[0080]FIG. 5A illustrates a (a) plan view showing the structure of the slit holes 15, 16 for inserting the concrete reinforcing materials, and a (b) cross section along a line b-b. In addition, FIG. 5B illustrates a (a) plan view showing the concrete reinforced structure 200 in which concrete reinforcing materials 100g, 100f are inserted into the slit-holes 15, 16, and a (b) cross section along a line b-b.

[0081]In the present embodiment, the same configurations, operations and effects as those of the first and second embodiments may not be described in detail.

[1. Step of Forming a Slit Hole]

[0082]For example, in a case where the concrete skeleton to be reinforced is a large-sized structure (for example, a structure such as a tunnel or a building), it is not desirable to prepare a concrete reinforcement material having the same length as the dimension of the concrete skeleton in the reinforcing direction, from points of view of the manufacturing, the managing / storing, the transportin...

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to Japanese Patent Application No. 2024-12122 filed on Jul. 26, 2024, entitled “Concrete Reinforcing Material and Concrete Reinforced Structure.” The entire contents of this application are hereby incorporated herein by reference.BACKGROUND

[0002] The disclosed technology relates to concrete reinforcing materials and concrete reinforced structures.

[0003] Japanese Unexamined Patent Application Publication No. 2012-26238 discloses a reinforcing method for suppressing an occurrence of a crack in a concrete surface layer and for performing a follow-up examination of a crack. In JP 2012-26238 A, a multilayered sheet in which carbon fibers having a latticelike structure are woven in a base material made of a transparent nonwoven fabric is used, as the reinforcement, and this multilayered sheet is fixed on a surface layer of a concrete with a transparent adhesive material. Consequently, it becomes possible to suppress an occurrence of a crack in a concrete and to perform an examination of a crack in a concrete.SUMMARY

[0004] This multilayered sheet has the advantage of being thin while significantly suppressing the increase of the volume of the concrete skeleton, but the deterioration due to the environmental exposures or the fire hazards is remarkable. Therefore, it is desirable to enhance a bearing force of a concrete skeleton without increasing its volume and mass when a bearing force of a concrete is lowered.

[0005] In view of the above-mentioned background, the present disclosure employs, for example, configurations described in the claims.

[0006] According to the present disclosure, a system or mechanism for enhancing a bearing force of a concrete skeleton without increasing at least one of its volume and mass is provided.

[0007] Problems, configurations, and effects other than those described above will be apparent from the following descriptions of embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic view showing a reinforcing material according to one embodiment.

[0009] FIG. 2 (a) to (c) are schematic views showing concrete reinforcing materials according to different embodiments.

[0010] FIG. 3A is a schematic perspective view showing a reinforcing material and a concrete skeleton provided with a slit for inserting the reinforcing material therein, according to one embodiment.

[0011] FIG. 3B is a schematic perspective view showing a concrete reinforced structure according to one embodiment.

[0012] FIG. 4A is a schematic perspective view showing a tunnel made of reinforced concrete.

[0013] FIG. 4B is a schematic perspective view showing a portion of a set of the concrete reinforcing material for reinforcing the tunnel illustrated in FIG. 4A and the tunnel provided with a slit for inserting the concrete reinforcing material.

[0014] FIG. 4C is a schematic perspective view showing a portion of the tunnel provided with the concrete reinforcing material in a slit illustrated in FIG. 4B.

[0015] FIG. 5A illustrates a (a) plan view showing the structure of a slit-hole according to one embodiment, and a (b) cross section along a line b-b.

[0016] FIG. 5 B illustrates a (a) plan view of a concrete reinforced structure that is formed by inserting the concrete reinforcing material in the slit-hole illustrated in FIG. 5A, and a (b) cross section along a line b-b.

[0017] FIG. 6 is a schematic perspective view showing a concrete reinforced structure according to a different embodiment.DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, a concrete reinforced structure, a concrete reinforcing material, and a method for reinforcing a skeleton made of concrete (also referred to concrete skeleton or concrete framework, same hereinafter) according to the present technology will be described with referring to the figures.

[0019] In general, the present technology is provided to form one or a plurality of slit holes on a surface layer of a skeleton (or body) made of concrete, and to reinforce the skeleton made of concrete by inserting one or a plurality of concrete reinforcing materials each having an elasticity along a longitudinal direction, in the slit holes. The concrete reinforced structure obtained in this way is considered to be, for example, reinforced without increasing its mass and volume by comparing to the original concrete skeleton. For example, the concrete reinforcing material is capable of functioning like a reinforcement member (or reinforcing steel member) and easily enhancing a bearing force with respect to the concrete skeleton. In addition, the concrete reinforcing material is made not to be exposed to a surface of the concrete skeleton, and accordingly, this suppresses the degradation thereof.First Embodiment[Concrete reinforcing material] Firstly, a concrete reinforcing material will be described.

[0020] FIG. 1 is a schematic view showing a reinforcing material 100 according to one embodiment. FIG. 2 (a) to (c) are schematic views showing concrete reinforcing materials 100 according to different embodiments.

[0021] A concrete reinforcing material 100 according to the present embodiment is an element for reinforcing a skeleton made of concrete (or skeleton containing concrete or concrete skeleton, for example, please refer to a concrete cube 6 and a concrete skeleton 14 illustrated in FIG. 2). The concrete reinforcing material 100 is typically formed to have an elongated shape, for example, it is formed to have an elongated sheet shape or elongated plate shape. The concrete reinforcing material 100 has an elasticity at least in one direction, typically in the longitudinal direction. For example, the concrete reinforcing material 100 has an elasticity (or tensile elastic modulus) which is higher than that of a concrete skeleton to be repaired. For example, this concrete reinforcing material 100 is capable of functioning as a reinforcement member in a reinforced concrete. From the aforementioned points of view, the concrete reinforcing material 100 may be referred as a reinforcing material or tension member which is capable of applying strength and / or endurance to the concrete skeleton.

[0022] In one embodiment, it is preferable that the concrete reinforcing material 100 has an elasticity which is higher than a required elasticity of the concrete skeleton 14. For example, the elasticity of the concrete reinforcing material 100 is preferably almost equal to or higher than that of the concrete skeleton 14 at the time of manufacturing. As a reference, the tensile elastic modulus of a concrete structure is generally estimated to be almost equal to or somewhat smaller than the compression elastic modulus. The compression elastic modulus (or Young's modulus) of the reinforced concrete is defined in various ways according to the design reference strength, but according to the design reference strength 80, it is defined to be equal to or larger than 3.80×104 N / mm2, and also according to the PHC piles (or Pretensioned Spun High Strength Concrete Piles), it is defined to be equal to or larger than 4.00×104 N / mm2.

[0023] In one embodiment, the concrete reinforcing material 100 includes high-elastic-modulus fibers (or high elasticity fibers). For example, the concrete reinforcing material 100 is a woven fabric made of high-elastic-modulus fibers. For example, as shown in FIG. 1, a woven fabric made of high-elastic-modulus fibers may be provided as a woven fabric including twistless or twisted fiber bundles 1 made up a predetermined number of bundles of high-elastic-modulus fibers (for example, filament yarns) as warps and also including wefts 2 for bundling the warps with each other. The woven fabric made of high-elastic-modulus fibers may be harden by further impregnating a resin material (for example, a thermosetting resin or thermoplastic resin), but this is not required. As illustrated in FIG. 1, for example, the woven fabric made of high-elastic-modulus fibers may be a fiber-reinforced plastic including high-elastic-modulus fibers. It is preferable that a plurality of fiber bundles constituting the warps are tightly connected by use of the wefts without forming a gap between the warps on the whole, in the concrete reinforcing material 100. On the other hand, any weft is available if it is capable of maintaining the connection of a plurality of the fiber bundles, as the weft, and the adjacent wefts may be separated from each other. For example, the wefts may be arranged side by side with an interval in a range of from 1 mm to 20 mm (for example, from 2 mm to 15 mm, or from 3 mm to 10 mm).

[0024] In the present specification, the above-mentioned high-elastic-modulus typically means that the tensile elastic modulus is approximately 100 cN / dtex or more, for example, the tensile elastic modulus is 200 cN / dtex or more, and preferably, it is approximately 353 cN / dtex (400 g / d) or more. The high-elastic-modulus fiber may have the tensile elastic modulus having a value of 353 cN / dtex or more, for example, 500 cN / dtex or more, 700 cN / dtex or more, 900 cN / dtex or more, 1000 cN / dtex or more, or 1200 cN / dtex or more, but are not limited thereto. In addition, each of the fiber bundles constituting the woven fabric may include high-elastic-modulus fibers, for example, having the number of 100 or more, and for example, the number of 10,000 or more. Examples of the high-elastic-modulus fibers include aramid fibers, carbon fibers, high density polyethylene fibers, polybenzazole-based fibers, glass fibers, and the like, but are not limited thereto.

[0025] The tensile elastic modulus may be measured, for example, according to the test methods for chemical fiber tire cords defined in JIS L1017: 2002.

[0026] For example, it is preferable that the concrete reinforcing material 100 has a density lower than that of the concrete skeleton to be reinforced. The density of the concrete skeleton is typically about 2.3 g / cm3 (in a case of the plain concrete), or about 2.45 g / cm3 in a case of the reinforced concrete. On the other hand, for example, the density of the high-elastic-modulus fibers, such as resin fibers or carbon fibers, may be made to be about 2.25 g / cm3 or less, for example, about 2 g / cm3 or less, about 1.9 g / cm3 or less, about 1.8 g / cm3 or less, about 1.6 g / cm3 or less, about 1.5 g / cm3 or less, about 1.4 g / cm3 or less, or about 1.3 g / cm3 or less, and the density of the glass fibers may be, for example, about 2.6 g / cm3 or less. Accordingly, the density of the concrete reinforcing material 100 made of high-elastic-modulus fibers is usually lower than that of the above-mentioned high-elastic-modulus fibers, and the density of the concrete reinforcing material 100 made of a woven fabric of high-elastic-modulus fibers may be even lower. The density of the concrete reinforcing material 100 may be, for example, about 2 g / cm3 or less, about 1.9 g / cm3 or less, about 1.8 g / cm3 or less, about 1.6 g / cm3 or less, about 1.5 g / cm3 or less, about 1.4 g / cm3 or less, about 1.3 g / cm3 or less, about 1.2 g / cm3 or less, or about 1 g / cm3 or less, etc. This makes it possible to reinforce the concrete skeleton of the reinforcing object without excessively increasing its weight.

[0027] Such a concrete reinforcing material may further include a resin which is impregnated into a plurality of fiber bundles. Since the resin is impregnated into a plurality of the fiber bundles, it is possible to integrally collect a plurality of the fiber bundles, and accordingly, it becomes possible to improve the handling thereof at the time of manufacturing, storing, and working at the work site, etc. In addition, since the resin covers the surfaces of a plurality of the fiber bundles, it is possible to suppress deterioration or transformation of the fiber bundles. Accordingly, it is possible to form the woven fabric made of the fiber bundles into a band plate shape or sheet shape.

[0028] The dimensions of the width, the length, and the thickness, etc., of the concrete reinforcing material 100 are not particularly limited. However, in a case where the reinforcement of a skeleton made of a reinforced concrete is performed, it is preferable that the width dimension of the concrete reinforcing material 100 is smaller than the “cover” dimension (for example, covering depth or thickness) of a concrete to be reinforced. From such a point of view, the width dimension of the concrete reinforcing material 100 may be in a range of “the covering depth—1 to 5” mm (or a range of from about a value determined by subtracting 5 mm from the covering depth to about a value determined by subtracting 1 mm from the covering depth). For example, it is preferable that it is formed into a band plate shape or sheet shape having a value in a range of from 20 mm to 100 mm (typically, in a range of from 25 mm to 80 mm).

[0029] In addition, for example, as illustrated in FIG. 2, in the concrete reinforcing materials 100, a plurality of the fiber bundles may be combined (for example, laminated or arranged in layers) in the thickness direction in accordance with the required stress (or reinforcing force). For example, two pieces of one layered reinforcing material having a sheet shape (which corresponds to one layered concrete reinforcing material 100) may be laminated to integrally form the concrete reinforcing material 100 as a (a) two-layered reinforcing material (or tension member) 3, three pieces of one layered reinforcing material may be laminated to integrally form a (b) three-layered reinforcing material (or tension member) 4, or four pieces of one layered reinforcing material may be laminated to integrally form a (c) four-layered reinforcing material (or tension member) 5. Although it is not concretely illustrated in the figures, five or more pieces (for example, 10 pieces, 20 pieces, or 50 pieces) of one layered reinforcing material having a sheet shape may be laminated to integrally form the concrete reinforcing material 100.

[0030] For example, the sheet shaped reinforcing materials which are overlapped each other in the concrete reinforcing materials 100 having such a layered structure may be mutually coupled and integrated by a resin material. In other words, the concrete reinforcing materials 100 having a layered structure may further include a resin material to be impregnated into the respective layers of a plurality of the fiber bundles. If the same resin is impregnated over neighboring layers of the reinforcing materials in the concrete reinforcing materials 100 having a layered structure, it becomes possible to prevent the intervention of a different resin layer (for example, adhesive layer) and accordingly to prevent the occurrence of scaling off of the layers and to suppress reduction in the flexibility (the details will be described later).

[0031] However, according to one embodiment, the concrete reinforcing material 100 having such a layered structure may be coupled by applying a predetermined quantity of an adhesive between the layers of the respective reinforcing materials (for example, woven fabric made of fiber bundles), for example, in a rage where a desired flexibility is realized.

[0032] The resin included in the concrete reinforcing material 100 preferably provide a flexibility to the concrete reinforcing material 100. With respect to the concrete reinforcing material 100, the “flexibility” refers to a property having a softness or flexibility without being damaged when it is folded. In one embodiment, the “flexibility” refers to a property capable of being folded equal to or less than the radius of curvature R 20 m without being damaged when the concrete reinforcing material 100 having the thickness of 1 mm is folded, at normal temperature (for example, at 25° C.). The “flexibility” with respect to the concrete reinforcing material 100 may have any one of the below-mentioned characteristics.

[0033] When the three-point bending test defined in JIS K7171: 2016 is performed with respect to a test piece of a concrete reinforcing material having dimensions of 80 mm, 10 mm, and 4 mm, the flexural modulus thereof is equal to or less than 15 GPa (typically, equal to or less than 10 GPa, equal to or less than 8 GPa, or equal to or less than 5 GPa).

[0034] The concrete reinforcing material 100 having the thickness dimension of 1 cm is capable of being folded (or bended) equal to or less than the radius of curvature R 20 m (for example, equal to or less than 10 m, equal to or less than 5 m, equal to or less than 3 m, equal to or less than 1 m, equal to or less than 50 cm, equal to or less than 30 cm).

[0035] The concrete reinforcing material 100 having the thickness dimension of 1 mm is capable of being folded (or bended) equal to or less than the radius of curvature R 2 m (for example, equal to or less than 1 m, equal to or less than 50 cm, equal to or less than 30 cm, equal to or less than 10 cm, equal to or less than 5 cm, equal to or less than 3 cm).

[0036] Incidentally, the “thickness” of the concrete reinforcing material 100 may be the average thickness of the measured thicknesses at three or more points along the longitudinal direction.

[0037] As such a resin, for example, it is possible to use various types of resin materials capable of realizing the above-mentioned flexibility in a cured state. In addition, it is also possible to use a resin in a liquid condition (resin composition) capable of being impregnated into the above-mentioned fibers or fiber bundles in an uncured state. For example, examples of the resin impregnated in the concrete reinforcing material 100 include a flexible epoxy resin, a urethane resin, a polyester, a polyamide, a polycarbonate, a polypropylene, a polyethersulfone, a triacetylcellulose, a polytetrafluoroethylene, a ThermoPlastic Elastomer (TPE), a Thermoplastic. Vulcanizates (TPV) and the like, each having a flexibility, but are not limited thereto. From points of view of the weather resistant, the environment resistant, and the durability, it is preferable to use a flexible epoxy resin or a urethane resin, among them.

[0038] The resin composition constituting the flexible resin may include, for example, a base polymer, a curing agent, and a modifying agent (or modifier) which contains a flexibility-imparting agent. Incidentally, the flexibility-imparting agent contained in the modifying agent may be included in the base polymer and / or the curing agent, as a form of a functional group, or it may also be included by combining a different modifying function (for example, as a crosslinking agent or the like). The flexibilizing moiety may be contained in any of the base polymer, the curing agent, and / or the flexibilizer. The resin composition may be composed of, but is not limited to, monomers and may be composed of any intermediate reactants. The resin composition may be composed of a resin that has the desired flexibility after curing. A flexible epoxy resin will be described below as an example of the flexible resin. However, a person skilled in the art will understand other flexible resins which are capable of being used in the present technology, by referring to the following descriptions of the flexible epoxy resin.

[0039] An epoxy resin in which a flexible group is introduced may be given as an example of the flexible resin. The epoxy resin composition constituting this epoxy resin may include, for example, an epoxy-based base polymer in an amount of more than 50 wt %. For example, from a point of view of having flexibility, the epoxy-based base polymer may be selected among various species of epoxy compound having two or more epoxy groups in one molecule. The epoxy compound may be a bifunctional epoxy compound having two epoxy groups in one molecule or a polyfunctional epoxy compound having three or more epoxy groups in one molecule. As the epoxy compound, solely one species or a combination of two or more species may be used. In one aspect, an epoxy compound which is liquid at normal temperature (for example, at 25° C.) may be preferably used, from a point of view of operability at a time when it is impregnated into a fiber.

[0040] In one embodiment, examples of the bifunctional epoxy compound may include, but are not limited to, bisphenol A epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins (i.e. epoxy compounds corresponding to that in structure resulting from hydrogenation of bisphenol A epoxy resins to convert aromatic rings to cycloalkyl rings), hydrogenated F epoxy resins, biphenyl epoxy resins, aliphatic epoxy resins (e.g. polypropylene glycol-based epoxy resins, etc.), 1,6-hexanediol diglycidyl ether, and polyethylene glycol diglycidyl ether.

[0041] In one embodiment, examples of the polyfunctional epoxy compound include, but are not limited to, novolac-based epoxy resins, glycidyl amine-based epoxy resins, biphenyl-based epoxy resins, triphenylmethane-based epoxy resins, dicyclopentadiene-based epoxy resins, glycerin-based epoxy resins, trimethylol propane-based epoxy resins, N,N,N′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and polyglycerol polyglycidyl ether. The number of epoxy groups in one molecule of the polyfunctional epoxy compound is at least 3 or greater, may be 4 or greater, or even 5 or greater. The number of epoxy groups in one molecule of the polyfunctional epoxy compound is usually suitably 10 or less, possibly 8 or less, or even 6 or less.

[0042] In some embodiments, as the epoxy compound, a bifunctional epoxy compound may be preferably used. The use of the bifunctional epoxy compound may be advantageous in obtaining a sealant sheet that gives a cured material showing suitable stretchiness. As the bifunctional epoxy compound, solely one species or a combination of two or more species may be used. In one embodiment, as the above-mentioned bifunctional epoxy compound, it is preferable to use an epoxy compound having a five-membered or larger carbon ring structure in the molecule. With a cured product of an impregnated resin formed using a bifunctional epoxy compound having such a structure, the resulting cured material tends to show high strength and good stretchiness. The five-membered or larger carbon ring structure may be, for instance, a benzene ring, naphthalene ring, cyclohexyl ring, etc. Examples of the epoxy compound including such a carbon ring structure include bisphenol A epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, hydrogenated bisphenol F epoxy resins, and biphenyl epoxy resins. In a preferable embodiment, as the bifunctional epoxy compound, a bisphenol F epoxy resin can be used. In a preferred embodiment, bisphenol A epoxy resins may be used as the above-mentioned bifunctional epoxy compound. For example, the bisphenol A liquid epoxy resins may have a weight-average molecular weight (Mw) in a range of from 300 to 600, but is not limited thereto. For example, the weight-average molecular weight may be a value which is determined according to Size Exclusion Chromatography (or SEC) method defined in JIS K7252-1:2016.

[0043] As the above-mentioned epoxy compound, one, two or more species of polyfunctional epoxy compound may be used in combination with a bifunctional epoxy compound or in place of the bifunctional epoxy resin. The use of a polyfunctional epoxy resin may increase the strength of the cured material. The combined use of a bifunctional epoxy compound and a polyfunctional epoxy compound may bring about an impregnated resin that provides a cured material that combines strength and stretchiness at a high level. In some embodiments, as the polyfunctional epoxy compound, it is possible to use a polyfunctional epoxy compound having an epoxy group-containing repeat unit (i.e. a polyfunctional epoxy polymer) and it is preferable to use, for instance, a novolac-based epoxy resin. Examples of the novolac-based epoxy resin include phenol novolac-based epoxy resins and o-cresol novolac-based epoxy resins. The use of a novolac-based epoxy resin may be advantageous in obtaining a sealant sheet that gives a cured material with high strength and good stretchiness. With the use of a novolac-based epoxy resin having a lower molecular weight, the stretchiness of the cured material tends to increase. For instance, it is preferable to use a phenol novolac-based epoxy resin that exists as liquid at room temperature.

[0044] Examples of the above-mentioned epoxy compounds include, but are not limited to, the product names of “EPICLON”, manufactured by DIC Co., Ltd, 840 to 850 series, TSR-960, 601, 1650-75MPX, EXA-4850 series, and the like; “jER (R)” which is a flexible type epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd, 871, 872, 872X75, 825, 827, 828, etc.; EPOLEAD GT401 etc., manufactured by Daicel Co., Ltd.; a flexible type epoxy resin, manufactured by Konishi Co., Ltd., QUICK 5, BOND E series, primers for microcrack repair, etc.

[0045] The epoxy resin composition may include, for example, a flexibility-imparting agent, a crosslinking agent, a curing accelerator, and the like, as the modifying agent.

[0046] As the flexibility-imparting agent, it is possible to use an element capable of imparting a flexibility to a cured material of a base polymer, for example, a compound capable of imparting a flexibility to an epoxy resin by adding a modifier or by introducing a flexible skeleton. Examples of the flexibility-imparting agent include alkylene ether-based compounds represented by a polyglycol diglycidyl ether (DGEPG) and the like; chain (non-cyclic) polycarboxylic acid anhydrides (long-chain fatty acid compounds) formed by polycondensation of polycarboxylic acids, represented by a polyazelaic acid anhydride or a polysebacic acid anhydride; aromatic compounds represented by a bisphenol A (BPA); liquid rubbers with a functional group at a terminal, represented by a carboxyl group-terminated polybutadiene nitrile rubber (CTBN); and silicone compounds represented by a modified silicone oil, etc., but are not limited thereto.

[0047] Examples of the crosslinking agent include: bisphenol A; epichlorohydrin type epoxy resin; ethyleneglycidylether; polyethylene glycol diglycidyl ether; glycerin diglycidyl ether; glycerin triglycidyl ether; 1,6-hexanediol glycidyl ether; trimethylolpropane triglycidyl ether; diglycidyl aniline; diamine glycidyl amine; N,N,N′,N′-tetraglycidyl-m-xylylenediamine; and 1,3-bis(N,N′-diamine glycidyl aminomethyl) cyclohexane, etc., but are not limited thereto. For the crosslinking agent, solely one species or a combination of two or more species may be used. In one embodiment, a bifunctional crosslinking agent having two crosslinking reactive groups (for example, ethylenically unsaturated groups, isocyanate groups, etc.) per molecule is used as at least one part of the crosslinking agent. The use of a bifunctional crosslinking agent facilitates the formation of a flexible crosslinked structure. For the bifunctional crosslinking agent, solely one species or a combination of two or more species may be used. Examples of the bifunctional crosslinking agents include bifunctional monomers such as a bifunctional (meth) acrylate, and a bifunctional isocyanate compound, etc. The bifunctional crosslinking agent may be used in combination with a tri- or polyfunctional crosslinking agent. Examples of the product name of the epoxy-based cross-linking agent include the product name of “TETRAD-X” and “TETRAD-C”, manufactured by Mitsubishi Gas Chemical Co., Ltd., the product name of “EPICLON CR-5L”, manufactured by DIC Co., Ltd., the product name of “DENACOL EX-512”, manufactured by Nagase ChemteX Co., Ltd., and the product name of “TEPIC-G”, manufactured by Nissan Chemical Industry Co., Ltd.

[0048] As the curing agent, it is possible to use a known or conventional curing agent (including, for example, a thermal polymerization initiator or a photopolymerization initiator) as a single kind or in combination of two or more kinds according to the base polymer, etc., to be used, as appropriate. As the epoxy curing agent, for example, it is possible to use a phenol-based curing agent, an amide-based curing agent, an amine-based curing agent, imidazoles, an acid anhydride-based curing agent, and an organic phosphine, as the polymerization initiator. In one embodiment, examples of the curing agent include a tertiary amine, a m-xylylenediamine and a modified aliphatic polyamine.

[0049] The epoxy compound used in the present embodiment was a bisphenol A-type liquid epoxy resin which was a polycondensate of 4,4′-isopropylidenediphenol and 1-chloro-2,3-epoxypropane in which a resin composition mixed with a polyamine-based curing agent in a mass ratio in a range of approximately from 1:1 to 10:1 was used, but the embodiment is not limited thereto. The mixed viscosity of the above-mentioned resin composition was approximately 200 mPa s or less at normal temperature, and the curing time was approximately 35 minutes (at 25° C.). With respect to a cured material as a single substance, for example, the epoxy compound is adjusted so as to fulfill any one or more of the following conditions of the compressive strength of 30 N / mm2 or more (for example, 50 N / mm2 or more, or 70 N / mm2 or more), the tensile shear adhesive strength of 10 N / mm2 or more (for example, 15 N / mm2 or more), the flexural strength of 35 N / mm2 or more (for example, 50 N / mm2 or more, or 70 N / mm2 or more), and the tensile adhesive strength of 1.6 N / mm2 or more (for example, 2 N / mm2 or more).

[0050] For example, from a point of view of enhancing the handling, the resin included in the concrete reinforcing material 100 according to one embodiment may be made to have a ratio of about 100 g or more, 200 g or more, 300 g or more, or 400 g or more, per one m2 of the fiber bundle and / or fiber woven fabric. Also, from a point of view of suitably exhibiting the flexibility, it may be made to have a rate of approximately 1,000 g or less, 800 g or less, or 600 g or less, per one m2 of the fiber bundle and / or fiber woven fabric. Also, with respect to the resin included in the concrete reinforcing material 100 having a layered structure according to one embodiment, for example, from a point of view of enhancing the handling, it may be made to have a rate of approximately 100 g or more, 300 g or more, 500 g or more, 700 g or more, or 900 g or more, per one kg of the fiber bundle and / or fiber woven fabric. Also, from a point of view of suitably exhibiting the flexibility, it may be made to have a rate of approximately 1,500 g or less, 1,200 g or less, or 1,000 g or less, per one kg of the fiber bundle and / or fiber woven fabric. With respect to the impregnation of the resin to the fiber bundle and / or fiber woven fabric, for example, it is possible to use the injection, atmospheric pressure impregnation, vacuum impregnation, vacuum pressure impregnation, or the like.

[0051] As described above, for example, the concrete reinforcing material 100 is made to have both tensile elasticity and flexibility so that it is possible to realize a reinforcing material which is excellent in the handleability at a time of the manufacturing, the storing, and the performing the construction at the work site. The concrete reinforcing material 100 according to the present technology may be provided, for example, with a flexibility to be wound on a roll. Also, the concrete reinforcing material 100 according to the present technology may be provided, for example, as a reinforcing material capable of being constructed to a curved surface such as a tunnel. In addition, the concrete reinforcing material 100 according to the present technology may be made to be performed the bending thereof, for example, to a reinforcing steel at the work site, by hand, and, for example, it may easily enhance the fixing force.[Method for Reinforcing a Concrete Skeleton]

[0052] Subsequently, a way of reinforcing a concrete skeleton by use of the concrete reinforcing material 100 will be described.

[0053] In general, the method for reinforcing a concrete skeleton according to the present technology includes the following steps of:

[0054] (1) forming a slit hole linearly on a surface layer part of a skeleton made of concrete, and

[0055] (2) inserting a concrete reinforcing material having an elongated shape, into the slit hole, to be aligned with an extending direction of the slit hole.[1. Step of Forming a Slit Hole]

[0056] FIG. 3A is a schematic perspective view illustrating the concrete reinforcing materials 100 and the concrete cube 6 (which is one example of the concrete skeleton) to be reinforced, according to one embodiment.

[0057] The concrete cube 6 to be reinforced is mainly constituted of concrete. The concrete cube 6 may be constituted of reinforced concrete in which one or a plurality of reinforcing steels are disposed. Alternatively, the concrete cube 6 may be constituted of concrete in which no reinforcing steel is disposed. For example, the concrete cube 6 according to the present embodiment is constituted of a concrete mass having a cubic shape (without a reinforcement) in which no reinforcing steel is disposed.

[0058] At the step of forming a slit hole, one or a plurality of slit holes 8, 9, 10 for inserting the concrete reinforcing material 100 are formed with respect to the concrete cube 6. Each of the slit holes 8, 9, 10 is preferably formed along a direction in which the tensile strength of the concrete reinforcing material 100 is desired to be increased. For example, one or a plurality of the slit holes 8, 9, 10 may be formed on a single skeleton. For example, two or more of the slit holes 8, 9, 10 may be formed on the same surface or different surfaces of a single skeleton. For example, a plurality of the slit holes 8, 9, 10 may be formed along the same direction or different directions with each other. In addition, each of the slit holes 8, 9, 10 may be formed to have a shape suitable to insert the concrete reinforcing material 100 having a shape which is suitable to apply a desired bearing strength to the concrete cube 6. For example, the slit holes 8, 9, 10 may be formed in a linear shape or curved shape on a surface layer part of the concrete cube 6.

[0059] In the embodiment illustrated in the FIG. 3A, a slit hole 8 on a top surface, a slit hole 9 on a side surface, and a slit hole 10 on a bottom surface are formed on the top surface, the front surface and the bottom surface of the concrete cube 6, respectively. Each of the slit hole 8 on the top surface and the slit hole 10 on the bottom surface is formed in a linear shape along the X-axis direction of the concrete cube 6, and the slit hole 9 on the side surface is formed in a linear shape along the Z-axis direction of the concrete cube 6. By making the slit holes 8, 9, 10 straight, the tensile strength in the direction along the straight line may be effectively increased. In addition, by separately forming the slit holes along the X-axis direction on the top surface and the bottom surface of the concrete cube 6, the tensile strength of the concrete cube 6 along the X-axis direction may be increased without causing unevenness as a whole.

[0060] Each of the concrete reinforcing materials 100a, 100b, 100c used in the present embodiment is made of filament threads having high tensile elastic modulus, and is formed to have a band plate shape (or plate shape) or tape shape having a substantially rectangular cross-section. The density of the concrete reinforcing materials 100a, 100b, 100c is equal to or less than about 1.2 g / cm3. Each of the respective slit holes 8, 9, 10 may be formed to have a dimension for accommodating the concrete reinforcing material 100 without projecting it therefrom. For example, each of the slit holes 8, 9, 10 may be formed to have a shape and a size corresponding to the concrete reinforcing material 100 so that the concrete reinforcing material 100 is capable of being fitted into it without play. Alternatively, each of the slit holes 8, 9, 10 may be formed to have a shape and a size slightly larger than the concrete reinforcing material 100 so that the concrete reinforcing material 100 is capable of being smoothly inserted into it.

[0061] In one embodiment, each of the slit-holes 8, 9, 10 may preferably have a groove having an approximately rectangular cross section, and the dimension in the width direction may be, for example, a sum of the thickness dimension of the concrete reinforcing material 100a, 100b, 100c to be inserted and a predetermined clearance. The clearance is designed, for example, as a dimension obtained by adding a size of a gap which is in a range of from 0.1 mm to 1 mm to both sides of the concrete reinforcing material 100a, 100b, 100c (or facing inner walls of the slit hole are separated from the concrete reinforcing material by a clearance in a range of from 0.1 mm to 1 mm). In addition, the dimension in the depth direction of the slit-holes 8, 9, 10 may be, for example, a dimension corresponding to the dimension in the width direction of the concrete reinforcing material 100a, 100b, 100c.

[0062] In this way, the slit holes 8, 9, 10 may be formed so that the dimension in the depth direction is made to be larger than the dimension in the width direction. For example, the slit holes 8, 9, 10 may be formed (for example, by grooving) by use of the grinder (for example, a grinding machine for free grinding). The grinder is also referred to as, for example, a grooving cutter. Accordingly, it is possible to increase the bonded area between the concrete cube 6 and the concrete reinforcing material 100a, 100b, 100c and also decrease the area where the respective concrete reinforcing materials 100a, 100b, 100c are exposed to the external environment. As a consequence, it becomes possible to effectively improve the bearing force of the concrete cube 6 and also suppress the deterioration in the concrete reinforcing materials 100a, 100b, 100c due to the environmental exposures.[2. Step of Inserting a Concrete Reinforcing Material]

[0063] FIG. 3B is a schematic perspective view showing the concrete reinforced structure 200 according to one embodiment.

[0064] At the step of inserting the concrete reinforcing material, the concrete reinforcing materials 100a, 100b, 100c are inserted into the slit-holes 8, 9, 10 of the concrete cube 6.

[0065] As the concrete reinforcing materials 100a, 100b, 100c, for example, materials each having a dimension corresponding to the longitudinal dimension of each of the slit holes 8, 9, 10 may be used. The concrete reinforcing materials 100a, 100b, 100c may be inserted into the slit holes 8, 9, 10, for example, after an adhesive is applied to each surface of the concrete reinforcing materials 100a, 100b, 100c. Then, the concrete reinforcing materials 100a, 100b, 100c are inserted into the slit holes 8, 9, 10 and the adhesive is made to be cured. Incidentally, the concrete reinforcing materials 100a, 100b, 100c may be inserted into the slit holes 8, 9, 10 after an adhesive is applied or filled into each of the slit holes 8, 9, 10. As the adhesive, for example, a resin material (for example, a thermosetting resin or thermoplastic resin) may be used.

[0066] In order to suitably apply the tensile force (or tension force) of the concrete reinforcing material 100a, 100b, 100c to the concrete cube 6, it is preferable that the adhesive has a higher adhesive force (or sticking force) with respect to the concrete. The adhesive strength of the adhesive after being cured may be, for example, defined as the tensile shear adhesive strength of 1 N / mm2 or more, preferably, 3 N / mm2 or more, 5 N / mm2 or more, or 10 N / mm2 or more, when measured in accordance with JIS K6850:1999. In this case, the adherend may be, for example, given as a surface of a concrete according to a standard formulation, based on the standard specifications for concrete structures, or a cutting surface made by a grinder. In addition, from a point of view of firmly fixing the concrete reinforcing material 100 to the slit hole, it is desirable that the adhesive has a high hardness. For example, the hardness of the adhesive after being cured may be defined as the durometer hardness (HDD) of 60 or more, preferably, 70 or more, or 80 or more, when measured in accordance with JIS K7215:1986. Examples of the adhesive for fixing the above-mentioned concrete reinforcing material 100 may include a thermosetting epoxy resin, a saturated polyester resin, a thermoplastic polyamide resin, a polycarbonate resin, and the like, but are not limited thereto.

[0067] Preferably, as the adhesive for fixing the concrete reinforcing material 100 to the slit hole, it is possible to use a material that satisfies a high adhesive strength and has a good adhesiveness (for example, compatibility) with the resin included in the concrete reinforcing material 100. From this point of view, for example, it is possible to use an adhesive made of an epoxy-based resin when the resin included in the concrete reinforcing material 100 is an epoxy resin. As one example of such an epoxy-based resin, an epoxy resin-based adhesive (for example, Bond E series manufactured by Konishi Co., Ltd.) may be given.

[0068] By curing the adhesive, the concrete reinforcing materials 100a, 100b, 100c are integrated with the concrete cube 6 inside the slit-holes 8, 9, 10, and accordingly, the concrete reinforced structure 200 is obtained. Incidentally, the concrete reinforcing materials 100a, 100b, 100c may be more firmly fixed to the concrete cube 6 by using an adhesive made of the same resin material that is impregnated in the concrete reinforcing materials 100a, 100b, 100c, or an adhesive made of a resin material compatible with the resin material that is impregnated in the concrete reinforcing materials 100a, 100b, 100c, as the adhesive.

[0069] By the above configuration, it is possible to apply a tensile force to the concrete cube 6 by fitting the concrete reinforcing materials 100a, 100b, 100c (or tensioning members) into the slit holes 8, 9, 10 of the concrete cube 6, and accordingly, it becomes possible to easily reinforce the concrete cube 6. Also, the concrete reinforcing materials 100a, 100b, 100c are accommodated in the slit holes 8, 9, 10 of the concrete cube 6. Therefore, it becomes possible to suppress the degradation of the concrete reinforcing materials 100a, 100b, 100c and reinforce the concrete cube 6 without increasing its volume. In addition, the density of the concrete reinforcing materials 100a, 100b, 100c is lower than that of the concrete cube 6 so that it is possible to reinforce the concrete cube 6 without increasing its weight before and after the repair. Furthermore, it is possible to reinforce the concrete cube 6 without impairing the appearance thereof.

[0070] According to the concrete reinforced structure 200 obtained in this way, the concrete reinforcing materials 100a, 100b, 100c impart a bearing force against a tension, to the concrete that is resistant to compression. For example, the concrete reinforcing materials 100a, 100b, 100c may impart the same or similar bearing force and tensile force thereto as those of the conventional reinforcing steel. Therefore, by using the above-mentioned concrete reinforcing materials 100a, 100b, 100c, it is possible to obtain the concrete reinforced structure 200 having more enhanced bearing force against compressive and tensile forces, by omitting, for example, the reinforcement work, the form construction work, and the concrete placement work. This is advantageous in that the cost and the construction period may be reduced by half.Second Embodiment

[0071] FIG. 4A is a schematic perspective view showing a tunnel provided as a concrete reinforced structure 200 according to one embodiment. FIG. 4A shows a cross-section of a part of the tunnel to facilitate the understanding. FIG. 4B is a partial perspective view showing a tunnel which is formed of reinforced concrete (which is an example of a concrete skeleton) during the period of the reinforcement, showing an enlarged part of a part illustrated by a circle in FIG. 4A. FIG. 4C is a partial perspective view showing a reinforcement structure of the tunnel, showing an enlarged part of a part illustrated by a circle in FIG. 4A.

[0072] In the present embodiment, the same configurations, operations and effects as those of the first embodiment may not be described in detail.

[0073] This tunnel is formed as a curved surface body 7 made of concrete having a substantially semi-cylindrical shape. In FIG. 4A to 4C, the X axis, the Y axis, and the Z axis correspond to the radial direction, the extending direction, and the up-down direction of the tunnel, respectively. In the present embodiment, the tunnel is reinforced along the Y-axis direction and the circumferential direction. For the reinforcement, concrete reinforcing materials 100d, 100e each made of a woven fabric of fiber bundles, and a gap filling member (or fill member or filler) 13 are used. Each of the concrete reinforcing materials 100d, 100e and the gap filling member 13 used in the present embodiment is formed into a band plate shape or tape shape each having substantially the same width-dimension and thickness-dimension.[1. Step of Forming a Slit Hole]

[0074] Firstly, at the step of forming a slit hole, as illustrated in FIG. 4B, slit holes 11, 12 are formed from the inside of the tunnel, with respect to the curved surface body 7 made of concrete. For example, firstly, a slit hole 11 (which is an example of a first slit hole) is formed along the extending direction (or Y-axis direction) of the tunnel, and then a slit hole 12 (which is an example of a second slit hole) is formed along the circumferential direction. In FIG. 4B, only one slit hole 11 extending along the extending direction of the tunnel is illustrated to be provided on the top part of the tunnel. However, the slit hole 11 extending along the extending direction may be formed not only at the top part of the tunnel, but also at a plurality of positions in the circumferential direction. Similarly, the slit holes 12 extending along the circumferential direction may also be formed at a plurality of positions in the extending direction of the tunnel. The slit hole 11 and the slit hole 12 intersect with each other when viewed in the Z-axis direction and communicate with each other.

[0075] The dimension of the slit hole 11 and the slit hole 12 in the width direction correspond to the dimension of the concrete reinforcing material 100d, 100e and the gap filling member 13 in the thickness direction. The depth of the slit hole 12 corresponds to the dimension of the concrete reinforcing material 100e in the width direction. The depth of the slit-hole 11 corresponds to the sum of the dimensions of the concrete reinforcing material 100d and the concrete reinforcing material 100e (or the gap filling member 13) in the width direction. The depth dimensions of the slit hole 11 and the slit hole 12 are larger than the dimensions in the width direction. However, it is desirable that the depth of the slit hole 11 is provided at a surface layer of the concrete skeleton (that is, at a part of the so-called “concrete cover” in which no reinforcing steel is disposed). In other words, the slit hole 11 preferably has the dimension in the depth direction so as to be equal to or smaller than the covering depth of the reinforced concrete. Accordingly, it is possible to carry out the construction work without damaging the reinforcing steel.[2. Step of Inserting]

[0076] Subsequently, at the step of inserting, firstly, the concrete reinforcing material 100d (which is an example of the first concrete reinforcing material) is inserted into the slit hole 11, and the concrete reinforcing material 100e (which is an example of the second concrete reinforcing material) is inserted into the slit hole 12. At this time, for example, the concrete reinforcing materials 100d, 100e may be preferably inserted (or fitted) in the slit-holes 11, 12 after a predetermined quantity of an adhesive is applied or filled to each of the slit-holes 11, 12. In addition, the slit hole 11 is made to be deep with respect to the concrete reinforcing material 100d so that it is possible to push the concrete reinforcing material 100d to a predetermined position in the depth of the slit hole 11 after the concrete reinforcing material 100d is inserted into the slit hole 11 and then the gap filling member 13 is further fitted into the slit hole 11. Since the concrete reinforcing material 100e is a woven fabric of fiber bundles formed into a band plate shape or tape shape, it is possible to easily deform it into an arc shape along the surface of the curved surface body 7 for inserting the same.

[0077] Incidentally, the gap filling member 13 may not be necessarily required. However, the gap filling member 13 is useful for pushing the concrete reinforcing material 100d to a predetermined position in the depth of the slit hole 11, for preventing the concrete reinforcing material 100d from being exposed to the atmosphere, and for enhancing the aesthetic appearance of the surface of the concrete curved surface body 7 after being repaired. In addition, it is possible to suppress the degradation of the concrete reinforcing material 100d due to the environmental exposures, the fire hazards, and the like. For example, as illustrated in FIG. 4C, after the adhesive is cured, it is possible to obtain the concrete reinforced structure 200 which is reinforced by the concrete reinforcing materials 100d, 100e.

[0078] With the above configuration, the concrete reinforcing material 100d and the concrete reinforcing material 100e are disposed in the slit-holes 11, 12 in a state of being twisted and / or crossed with each other. This increases the tensile strength of the concrete reinforced structure 200 with respect to the direction in which the concrete reinforcing material 100d extends and to the direction in which the concrete reinforcing material 100e extends. Accordingly, it is possible to reinforce the concrete skeleton in desired directions.

[0079] If a long period of time elapses, concrete skeletons such as tunnels may be superannuated, and cracks may be generated in the concrete or rust may be generated in the reinforcing steel, and as a result, strength (or tension) of the concrete skeletons may be remarkably lowered. Even in such a case, by use of the above-mentioned method, it is possible to reinforce the concrete skeleton without increasing its mass and volume and also without significantly changing its appearance.Third Embodiment

[0080] FIG. 5A illustrates a (a) plan view showing the structure of the slit holes 15, 16 for inserting the concrete reinforcing materials, and a (b) cross section along a line b-b. In addition, FIG. 5B illustrates a (a) plan view showing the concrete reinforced structure 200 in which concrete reinforcing materials 100g, 100f are inserted into the slit-holes 15, 16, and a (b) cross section along a line b-b.

[0081] In the present embodiment, the same configurations, operations and effects as those of the first and second embodiments may not be described in detail.[1. Step of Forming a Slit Hole]

[0082] For example, in a case where the concrete skeleton to be reinforced is a large-sized structure (for example, a structure such as a tunnel or a building), it is not desirable to prepare a concrete reinforcement material having the same length as the dimension of the concrete skeleton in the reinforcing direction, from points of view of the manufacturing, the managing / storing, the transporting, and the performing the construction at the work site, etc. Accordingly, it is preferable that when a large-sized skeleton made of concrete is reinforced, for example, a concrete reinforcing material 100 having a dimension easy to handle is connected and used.

[0083] In such a case, at the step of forming a slit hole, for example, as illustrated in FIG. 5A, with respect to the concrete 14, the first slit hole 15 and the second slit hole 16 are preferably formed to be extended along the reinforcing direction and to be adjacent to each other only in a predetermined dimension 17. For example, the first slit hole 15 and the second slit hole 16 are substantially parallel to each other and communicate with each other at the adjacent part. For example, such a slit may be formed, at first, by forming a first slit hole 15 by using a grinder (for example, a grinding machine for free grinding) 20 which is set to a predetermined cutting groove width, then by moving (or offsetting) the grinder 20 in the width direction by the width of the groove and by forming a second silt hole 16. At this time, the second slit hole 16 is preferably formed such that one end of the first slit hole 15 and the other end of the second slit hole 16 are adjacent to each other by the predetermined dimension 17.[2. Step of Inserting]

[0084] Subsequently, at the step of inserting, as illustrated in FIG. 5B, for example, a first concrete reinforcing material 100f is inserted into the first slit hole 15, and a second concrete reinforcing material 100g is inserted into the second slit hole 12. At this time, it is preferable that the concrete reinforcing materials 100f, 100g are inserted therein, for example, after applying or filling a predetermined quantity of an adhesive 19 to each of the slit holes 11, 12. In addition, it is preferable that one end of the first concrete reinforcing material 100f and the other end of the second concrete reinforcing material 100g are fitted in the slit holes 11, 12 so as to be adjacent to each other by a predetermined dimension 18. In the example illustrated in FIGS. 5A and 5B, the dimension 18 is significantly smaller than the dimension 17, but the dimension 17 and the dimension 18 may be generally the same.

[0085] In addition, a layer of an adhesive 19 exists between the first concrete reinforcing material 100f and the second concrete reinforcing material 100g. The first concrete reinforcing material 100f and the second concrete reinforcing material 100g are connected with the predetermined dimension 18 through the layer of the adhesive 19. Accordingly, the concrete 14 may be continuously reinforced by the first concrete reinforcing material 100f and the second concrete reinforcing material 100g.

[0086] In the example illustrated in FIG. 5B, the layer of the adhesive 19 has a sufficient thickness, but the layer of the adhesive 19 may have a thickness of about a clearance. Alternatively, at least a part or all of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be in contact with each other in the area indicated by the dimension 18. In this case, the second slit hole may be offset from the first slit hole 15 by a dimension narrower than the groove width. Accordingly, the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be more firmly connected with each other.

[0087] In the present embodiment, the first slit hole 15 and the second slit hole are made to be parallel to each other, but as long as they are continuous with the predetermined dimension 17, they need not necessarily be parallel to each other. In addition, the first concrete reinforcing material 100f and the second concrete reinforcing material 100g are also made to be parallel to each other, but as long as they are continuous with the predetermined dimension 18, they need not necessarily be parallel to each other. It is preferable that the dimension 17 of the communicating part of the first slit hole 15 and the second slit hole may be, for example, in a range of from 250 mm to 300 mm, but not limited to this. Also, it is preferable that the dimension 18 of the connecting part of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be in a range of from 200 mm to 250 mm, but not limited to this. Accordingly, the first concrete reinforcing material 100f and the second concrete reinforcing material 100g may be easily and firmly coupled.

[0088] As the grinder 20, for example, it is possible to use an adjustable grooving grinder provided with grinding teeth of which groove width is capable of freely being adjusted. In addition, it is possible to make the first slit hole 15 and the second slit hole deeper than the widths of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g so as to cover the surfaces of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g with the adhesive 19 after being inserted into the first slit hole 15 and the second slit hole, respectively, in order to seal them with air-tightness and fluid-tightness. Alternatively, it is also possible to dispose gap filling members at the surfaces of the first concrete reinforcing material 100f and the second concrete reinforcing material 100g so as to cover the first concrete reinforcing material 100f and the second concrete reinforcing material 100g, respectively.Fourth Embodiment

[0089] FIG. 6 is a schematic perspective view showing a concrete reinforced structure 200 according to one embodiment. In the concrete reinforced structure 200 of the present embodiment, at least one end of the concrete reinforcing material 100 is bent. The same configurations, operations and effects as those of the first, second and third embodiments may not be described in detail.

[0090] According to the present embodiment, at the step of forming a slit hole, at least one end (in this example, both ends) of the slit hole is bent in the concrete skeleton to be reinforced. For example, the form of the bending may be decided as with the case of the bending method of a reinforcing steel. In one example, it may be bent along a nearly U-shape with respect to the slit hole extending in the longitudinal direction, for example, so as to be inclined at an angle of 90 degrees, 135 degrees, or 180 degrees. At the time, for example, it is possible to adapt a bend inside radius for the case of utilizing a reinforcing steel corresponding to the tensile elastic modulus of the concrete reinforcing material 100, as the bend inside radius of the bending portion. Here, it is bent with a radius of curvature of approximately 5 cm. However, when forming the slit hole by using a grinder is difficult, at least one end of the slit hole may be inclined in a direction crossing the longitudinal direction (or extending direction) of the slit hole.

[0091] Subsequently, at the step of inserting, the concrete reinforcing material 100 on which an adhesive is applied is inserted into the formed slit hole. For example, the concrete reinforcing material 100 according to the present embodiment is made to have a band plate shape having a length of about 200 m, and is maintained while being wound on a roll (e.g., about 10 cm in diameter at the core). Accordingly, at the step of inserting, the concrete reinforcing material 100 is fed out and cut at a predetermined length at the work site, and then inserted into the slit hole while being bent in accordance with the slit hole. The end of the concrete reinforcing material 100 is bent with a radius of curvature of approximately 5 cm to match the slit hole. As the adhesive, for example, it is possible to use an epoxy resin. Then, when the adhesive is cured, the concrete reinforced structure 200 related to the present technology may be obtained.

[0092] At least one end (in this example, both ends) of the concrete reinforcing material 100 is bent in the concrete reinforced structure 200. Accordingly, for example, if the concrete skeleton is expanded, a tensile force (or tension force) is generated along the concrete reinforcing material 100 in the concrete reinforced structure 200. At the time, since at least one end (in this example, both ends) of the concrete reinforcing material 100 is bent, the fixing force with respect to the concrete skeleton is enhanced. Accordingly, it is possible to effectively reinforce the concrete skeleton.

[0093] The present disclosure is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for the purpose of clearly illustrating the present disclosure, and are not necessarily limited to those having all the described configurations. In addition, a part of a configuration of one embodiment may be replaced with a configuration of different embodiment, and a configuration of one embodiment may be added to a configuration of different embodiment. Further, it is possible to add, delete, or replace a part of a configuration of each embodiment with other configuration. The present disclosure discloses any one or any combination of two or more of the features recited in the claims.EXPLANATION OF REFERENCE NUMERALS1 . . . Fiber bundle,

[0095] 2 . . . Wefts,

[0096] 3 . . . Two-layered tension member,

[0097] 4 . . . Three-layered tension member,

[0098] 5 . . . Four-layered tension member,

[0099] 6 . . . Concrete cube,

[0100] 7 . . . Concrete curved surface body,

[0101] 7a . . . Enlargement of the concrete curved surface body,

[0102] 8 . . . Slit hole on a top surface,

[0103] 9 . . . Slit hole on a side surface,

[0104] 10 . . . Slit hole on a bottom surface,

[0105] 11 . . . Slit hole along y direction,

[0106] 12 . . . Slit hole along x direction,

[0107] 13 . . . Gap filling member (or fill member or filler),

[0108] 14 . . . Concrete (or concrete skeleton),

[0109] 15 . . . Slit hole along l direction,

[0110] 16 . . . Slit hole along r direction,

[0111] 17 . . . Dimension of a slit hole,

[0112] 18 . . . Dimension of a tension member,

[0113] 19 . . . Adhesive,

[0114] 20 . . . Grinder (or grinding machine for free grinding).

[0115] 100 . . . Concrete reinforcing material (or tension member),

[0116] 100a . . . . Tension member on a top surface,

[0117] 100b . . . . Tension member on a side surface,

[0118] 100c . . . . Tension member on a bottom surface,

[0119] 100d . . . . Tension member along Y direction,

[0120] 100e . . . . Tension member along X direction,

[0121] 100f . . . . Tension member along L direction,

[0122] 100g . . . . Tension member along R direction,

[0123] 200 . . . Concrete reinforced structure,

Examples

first embodiment

[Concrete reinforcing material] Firstly, a concrete reinforcing material will be described.

[0020]FIG. 1 is a schematic view showing a reinforcing material 100 according to one embodiment. FIG. 2 (a) to (c) are schematic views showing concrete reinforcing materials 100 according to different embodiments.

[0021]A concrete reinforcing material 100 according to the present embodiment is an element for reinforcing a skeleton made of concrete (or skeleton containing concrete or concrete skeleton, for example, please refer to a concrete cube 6 and a concrete skeleton 14 illustrated in FIG. 2). The concrete reinforcing material 100 is typically formed to have an elongated shape, for example, it is formed to have an elongated sheet shape or elongated plate shape. The concrete reinforcing material 100 has an elasticity at least in one direction, typically in the longitudinal direction. For example, the concrete reinforcing material 100 has an elasticity (or tensile elastic modulus) which is hi...

second embodiment

[0071]FIG. 4A is a schematic perspective view showing a tunnel provided as a concrete reinforced structure 200 according to one embodiment. FIG. 4A shows a cross-section of a part of the tunnel to facilitate the understanding. FIG. 4B is a partial perspective view showing a tunnel which is formed of reinforced concrete (which is an example of a concrete skeleton) during the period of the reinforcement, showing an enlarged part of a part illustrated by a circle in FIG. 4A. FIG. 4C is a partial perspective view showing a reinforcement structure of the tunnel, showing an enlarged part of a part illustrated by a circle in FIG. 4A.

[0072]In the present embodiment, the same configurations, operations and effects as those of the first embodiment may not be described in detail.

[0073]This tunnel is formed as a curved surface body 7 made of concrete having a substantially semi-cylindrical shape. In FIG. 4A to 4C, the X axis, the Y axis, and the Z axis correspond to the radial direction, the ex...

third embodiment

[0080]FIG. 5A illustrates a (a) plan view showing the structure of the slit holes 15, 16 for inserting the concrete reinforcing materials, and a (b) cross section along a line b-b. In addition, FIG. 5B illustrates a (a) plan view showing the concrete reinforced structure 200 in which concrete reinforcing materials 100g, 100f are inserted into the slit-holes 15, 16, and a (b) cross section along a line b-b.

[0081]In the present embodiment, the same configurations, operations and effects as those of the first and second embodiments may not be described in detail.

[1. Step of Forming a Slit Hole]

[0082]For example, in a case where the concrete skeleton to be reinforced is a large-sized structure (for example, a structure such as a tunnel or a building), it is not desirable to prepare a concrete reinforcement material having the same length as the dimension of the concrete skeleton in the reinforcing direction, from points of view of the manufacturing, the managing / storing, the transportin...

Claims

1. A concrete reinforced structure comprising:a skeleton containing concrete, the skeleton having a slit hole linearly formed on a surface layer part of the skeleton, anda concrete reinforcing material having an elasticity in a longitudinal direction, wherein the concrete reinforcing material is inserted in the slit hole such that the longitudinal direction is aligned with an extending direction of the slit hole.

2. The concrete reinforced structure according to claim 1, wherein the concrete reinforcing material includes a high-elastic-modulus fiber having a tensile elastic modulus of about 353 cN / dtex or more in the longitudinal direction.

3. The concrete reinforced structure according to claim 2, wherein the concrete reinforcing material has a band plate shape and includes a plurality of fiber bundles and wefts for bundling a plurality of the fiber bundles arranged side by side, wherein each of the fiber bundles includes a plurality of the high-elastic-modulus fibers.

4. The concrete reinforced structure according to claim 3, wherein the concrete reinforcing material further comprises a resin impregnated into the fiber bundles.

5. The concrete reinforced structure according to claim 3, wherein the concrete reinforcing material includes a plurality of the fiber bundles connected into a band plate shape, andwherein a plurality of the connected fiber bundles are arranged in layers and coupled by a resin.

6. The concrete reinforced structure according to claim 1, wherein the concrete reinforcing material includes a high-elastic-modulus fiber having a tensile elastic modulus of about 353 cN / dtex or more in the longitudinal direction, and a resin impregnated into the high-elastic-modulus fiber, andwherein the concrete reinforcing material has a flexibility.

7. The concrete reinforced structure according to claim 1, wherein the concrete reinforcing material is fixed inside the slit hole by an adhesive.

8. The concrete reinforced structure according to claim 1, wherein the slit hole has a depth dimension larger than a width dimension of the slit hole,wherein the concrete reinforcing material has a width dimension larger than a thickness dimension of the concrete reinforcing material, andwherein the concrete reinforcing material is inserted in the slit hole such that a width direction of the concrete reinforcing material is aligned with a depth direction of the slit hole.

9. The concrete reinforced structure according to claim 1, wherein a dimension in a width direction of the slit hole is designed such that facing inner walls of the slit hole are separated from the concrete reinforcing material by a clearance in a range of from about 0.1 mm to about 1 mm.

10. The concrete reinforced structure according to claim 1, wherein the skeleton containing concrete is made of reinforced concrete, andwherein the slit hole has a dimension in a depth direction equal to or smaller than a covering depth of the reinforced concrete.

11. The concrete reinforced structure according to claim 1, wherein the slit hole has a dimension in a depth direction equal to or larger than a dimension in a depth direction of the concrete reinforcing material or a dimension in a depth direction of a set of the concrete reinforcing material and a gap filling member arranged if needed, andwherein the concrete reinforcing material or the set of the concrete reinforcing material and the gap filling member is provided in the slit hole so as not to protrude from a surface of the skeleton containing concrete.

12. The concrete reinforced structure according to claim 1, wherein the slit hole includes a first slit hole and a second slit hole communicated with the first slit hole,wherein the concrete reinforcing material includes a first concrete reinforcing material provided inside the first slit hole and a second concrete reinforcing material provided inside the second slit hole, andwherein the first concrete reinforcing material and the second concrete reinforcing material are connected at a communicating part of the first slit hole and the second slit hole.

13. The concrete reinforced structure according to claim 1, wherein the slit hole includes a first slit hole and a second slit hole that extend in different directions and communicate with each other,wherein the concrete reinforcing material includes a first concrete reinforcing material provided inside the first slit hole, and a second concrete reinforcing material provided inside the second slit hole, andwherein the first concrete reinforcing material and the second concrete reinforcing material are arranged to cross with each other inside the slit hole.

14. A concrete reinforcing material for being used in the concrete reinforced structure as recited in claim 1,wherein the concrete reinforcing material includes a high-elastic-modulus fiber having a tensile elastic modulus of about 353 cN / dtex or more in the longitudinal direction.

15. A method for reinforcing a skeleton containing concrete, comprising:forming a slit hole linearly on a surface layer part of the skeleton containing concrete, and inserting a concrete reinforcing material having an elongated shape in the slit hole such that a longitudinal direction of the concrete reinforcing material is aligned with a longitudinal direction of the slit hole.

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