JP3979912B2 - Reinforcing prepreg sheet and method for reinforcing concrete structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reinforcing prepreg sheet and a method for reinforcing a concrete structure, and more particularly, to a method for attaching a prepreg sheet to a reinforcing surface for reinforcement.
[0002]
[Prior art]
For example, in the case of seismic reinforcement of concrete structures such as reinforced concrete (RC) columns, because the environment is subject to restrictions such as construction time, construction range, materials and heavy equipment carry-in route, etc. It is required that this is possible.
[0003]
Under such a requirement, this applicant, in Japanese Patent Laid-Open No. 10-37485, forms a reinforced coating layer by winding a metal mesh around a concrete structure and then impregnating the molten resin with spray-up or hand-layup. Proposed construction method.
[0004]
According to such a construction method, since the steel material constituting the metal mesh is excellent in tensile strength, the shear strength of the RC member can be greatly improved. In addition, because steel material has tensile toughness, it has a feature that it does not break immediately after the yield of steel material. Therefore, the buckling of the axial rebar is prevented by the effect of preventing the concrete from jumping out. Can be improved.
[0005]
However, the above conventional method impregnates a metal mesh with molten resin by spraying up or hand laying up at the construction site, so it takes a long time to develop strength and the workability is not good. It does not completely satisfy the requirements.
[0006]
By the way, in Japanese Patent Application Laid-Open No. 2000-2656680, a prepreg sheet in which a light-transmitting reinforcing fiber is impregnated with a photocurable resin is wound around a concrete structure such as an RC pillar, and this prepreg sheet is irradiated with light and cured. A seismic reinforcement method for reinforcement is disclosed. According to this construction method, since the prepreg sheet is quickly cured by irradiating light, the strength can be expressed in a short time, and the material can be produced in a factory or the like and brought into the field. There is an advantage that workability is good.
[0007]
[Problems to be solved by the invention]
The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to provide a reinforcing prepreg sheet and a concrete structure that can exhibit strength in a short time and improve workability while taking advantage of the excellent characteristics of a metal mesh as a reinforcing material. It is to provide a reinforcing method.
[0008]
[Means for Solving the Problems]
This inventor, as a result of earnest research to solve the above problems, the metal mesh itself does not transmit light, but even a prepreg sheet made of a photo-curable resin with the metal mesh as a reinforcing material, It has been found that since the light is irregularly reflected around the mesh wire, the light can reach the back surface of the sheet and the resin can be cured.
[0009]
The present invention has been made on the basis of the above knowledge, and employs the following means.
That is, the present invention provides a reinforcing prepreg sheet obtained by impregnating a photocurable resin into a reinforcing material made of a metal mesh in which the ratio a / b between the vertical wire spacing a and horizontal wire spacing b is less than 1. It is in. A light-transmitting reinforcing fiber may be disposed on one side or both sides of the metal mesh to form a composite reinforcing material.
[0010]
Further, according to the present invention, a prepreg sheet formed by impregnating a photocurable resin into a reinforcing material made of a metal mesh in which a ratio a / b between a space a between vertical strands and a space b between horizontal strands is less than 1 is applied to concrete. The method of reinforcing a concrete structure is characterized by wrapping or sticking to a reinforcing surface of a structure and curing the prepreg sheet by light irradiation. A prepreg sheet in which a light-transmitting reinforcing fiber is disposed on one side or both sides of a metal mesh to form a composite reinforcing material may be used.
Furthermore, from a prepreg sheet (first prepreg sheet) obtained by impregnating a reinforcing material made of a metal mesh with a photocurable resin, a metal mesh, and a light-transmitting reinforcing fiber disposed on one or both sides thereof A prepreg sheet (second prepreg sheet) formed by impregnating a photocurable resin into a reinforcing material to be laminated on a reinforcing surface of a concrete structure and wound or attached to each of the first and second prepreg sheets. You may make it harden by light irradiation.
[0011]
Alternatively, a thermosetting resin sheet may be attached to one side of the prepreg sheet and integrated, and the thermosetting resin sheet side may be attached to the reinforcing surface of the concrete structure. After the thermosetting resin sheet is attached to the reinforcing surface of the concrete structure, the prepreg sheet may be attached to the thermosetting resin sheet surface.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a first embodiment of a prepreg sheet according to the present invention. The prepreg sheet 10 includes a metal mesh 1 as a reinforcing material, and the metal mesh 1 is impregnated with a photocurable resin 2. FIG. 2 shows a second embodiment of the prepreg sheet 10, in which the reinforcing material is composed of a metal mesh 1 and light-transmitting reinforcing fibers 3 arranged on one side thereof, and this reinforcing material is impregnated with a photocurable resin 2. Let it be a prepreg sheet. The light transmissive reinforcing fibers 3 may be disposed not only on one side but also on both sides of the metal mesh 1. In FIG.1 and FIG.2, the code | symbol 4 has shown the protective film.
[0013]
Steel or stainless steel is used as the wire material of the metal mesh 1. The metal mesh 1 may be composed of a wire made of a metal material that diffusely reflects light, and aluminum or copper can be used in addition to steel, but steel is excellent in tensile strength and tensile toughness, particularly stainless steel. In the case of steel, since it also has rust prevention property, it is suitable as the metal mesh 1. The metal mesh 1 preferably has a wire diameter of 0.2 to 0.4 mm and a mesh number of 10 to 60.
[0014]
As shown in FIG. 3 (a), the metal mesh 1 may have a ratio a / b of the space a between the vertical strands and the space b between the horizontal strands as 1. However, in the seismic reinforcement of a concrete structure, The tensile strength required for reinforcement has directionality. Accordingly, the wire spacing is made dense in the direction where the tensile strength is required, while the wire spacing is made sparse in the direction perpendicular to the direction, that is, a / b is 1 as shown in FIG. You may make it become less.
[0015]
As the light-transmitting reinforcing fiber 3 in the prepreg sheet 10 of FIG. 2, a glass fiber that is excellent in light transmittance and strength and inexpensive is used. In addition to this, an aramid fiber, an acrylic fiber, a transparent polyester fiber, a polyethylene fiber, a nylon fiber, or the like can be used as the light-transmitting reinforcing fiber. One type of fiber to be used may be selected, or a plurality of types may be selected.
[0016]
Conventionally, FRP prepreg sheets using glass fiber as a reinforcing material have short glass fibers arranged as a chopped strand mat. On the other hand, in the present embodiment, since the tensile strength necessary for reinforcement is directional in the seismic reinforcement of the concrete structure as described above, the glass fiber is long fiber as shown in FIG. Are arranged in a uniaxial direction according to the directionality required for reinforcement. Furthermore, with this arrangement as a reference, a triaxial arrangement as shown in FIG.
[0017]
As the photocurable resin 2, a resin material that is cured by crosslinking reaction with ultraviolet rays is usually used, and it may be selected from unsaturated polyester resin, phenol resin, acrylic resin, polyamide resin, epoxy resin, epoxy acrylate resin, and the like. it can. As the photocuring agent added to the resin, a photocuring agent that absorbs ultraviolet rays having a wavelength range of 365 to 410 nm is usually used. In addition, a photooxidant, a curing aid, a thickener, a filler and the like are appropriately added to the resin as a curing property and viscosity adjusting agent.
[0018]
FIG. 5 shows an example in which an RC column which is a concrete structure is reinforced using the prepreg. First, after the primer treatment is applied to the reinforcing surface of the RC pillar, the prepreg sheet 10 is wound while peeling off the protective film 4 on the back surface. After the sheet 10 is wound, light is irradiated. Thereby, photocurable resin hardens | cures and the RC pillar is reinforced. At that time, the steel mesh itself does not transmit light, but diffusely reflects light, so that the light reaches the back surface of the sheet and the entire resin is cured. After the sheet 10 is cured, the protective film 4 on the surface is peeled off. As the light source, an ultraviolet fluorescent lamp, a high-pressure mercury lamp, a metal halide lamp, or the like can be used, but it may be cured by sunlight. The prepreg sheet 10 can be made into a plurality of windings according to the required strength.
[0019]
6 and 7 are cross-sectional views showing another embodiment. When light transmission to the back surface of the prepreg sheet 10 is incomplete, the thermosetting resin sheet 11 may be interposed between the base material 50 of the concrete structure and the prepreg sheet 10. In this case, as shown in FIG. 6, the thermosetting resin sheet 11 may be attached to the back surface of the prepreg sheet 10 and integrated to the base material 50. Alternatively, as shown in FIG. 7, the thermosetting resin sheet 11 may be pasted on the base material 50 in advance, and the prepreg sheet 10 may be pasted on the sheet 11. In addition, as the resin material of the thermosetting resin sheet, the above-listed resins that do not add a photocuring agent can be used.
[0020]
According to the reinforcing method as described above, the following advantages can be obtained.
Since a prepreg sheet made of a photocurable resin is used, it can be cured in a short time by irradiating light, and 100% strength can be expressed. Thereby, for example, even in the case of reinforcement construction within the railway track site, the strength is expressed, so that it is safe to receive wind pressure from a train or the like on the same day, and division construction is also possible. In addition, since the sheet can be cut into an arbitrary length for construction, there is no need for a heavy machine or the like for carrying in the material, and it is easy.
[0021]
Since the steel mesh excellent in tensile strength is used as the reinforcing material, the shear strength of the RC member can be improved. In addition, steel mesh has high tensile toughness and does not break immediately after yielding, so it can prevent buckling of the axial rebar due to the effect of preventing concrete jumping, and improve the bending deformation performance of RC members. Can do.
[0022]
Furthermore, according to the prepreg sheet shown in FIG. 2 in which the reinforcing material is made of a composite material of steel mesh and glass fiber, the following advantages are obtained.
In the case of a conventional FRP sheet using carbon fiber, glass fiber, or the like as a reinforcing material, the bending deformation performance is ensured by the fiber forcibly restraining the axial rebar. In such a case, the strength of the RC member is suddenly lost when the reinforcing material is broken.
[0023]
On the other hand, when the reinforcing material is a prepreg sheet made of a composite material of steel mesh and glass fiber, the tensile property is a shape that combines the properties of glass fiber and steel as shown in FIG. That is, even if the glass fiber breaks, the steel mesh is arranged, so that it does not break immediately due to its tensile toughness. Therefore, even if the glass fiber breaks, the steel member does not cause a sudden decrease in the proof strength of the RC member, and the RC member can be prevented from being broken.
[0024]
A first prepreg sheet (hereinafter referred to as a steel mesh sheet) in which the reinforcing material is made of only steel mesh shown in FIG. 1 and a second material in which the reinforcing material is made of a composite material of steel mesh and glass fiber shown in FIG. A prepreg sheet (hereinafter referred to as a composite sheet) can be used in combination. That is, a steel mesh sheet and a composite sheet may be laminated and wound around a concrete structure.
[0025]
In this case, by appropriately changing the combination of the steel mesh sheet and the composite sheet (for example, the number of windings in the case of winding and the number of sheets in the case of pasting), the proportion of the metal constituting the reinforcing layer in the reinforcing layer, It is possible to change the ratio of the occupation. As a result, free combinations are possible depending on the seismic reinforcement performance required for, for example, a bridge pier. In some cases, the combination can be partially changed with respect to the total length of the pier.
[0026]
【The invention's effect】
As described above, according to the present invention, the excellent characteristics of the metal mesh as a reinforcing material can be utilized, strength can be developed in a short time, and workability can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a prepreg sheet according to the present invention.
FIG. 2 is a cross-sectional view showing a second embodiment.
FIG. 3 is a plan view showing an arrangement example of strands in a metal mesh.
FIG. 4 is a plan view showing an example of fiber arrangement in glass fibers.
5A and 5B show an embodiment of a reinforcing method, where FIG. 5A is a front view and FIG. 5B is a cross-sectional view.
FIG. 6 is a cross-sectional view showing another embodiment of a reinforcing method.
FIG. 7 is a cross-sectional view showing another embodiment of a reinforcing method.
FIG. 8 is a diagram showing tensile properties of the prepreg sheet shown in FIG.
[Explanation of symbols]
1: Metal mesh (steel mesh)
2: Photocurable resin 3: Light-transmitting reinforcing fiber (glass fiber)
4: Protective film 10: Pre-preg sheet 11: Thermosetting resin sheet

Claims (7)

A reinforcing prepreg sheet obtained by impregnating a photo-curing resin into a reinforcing material made of a metal mesh in which a ratio a / b between an interval a between vertical strands and an interval b between horizontal strands is less than 1 . Light is applied to a reinforcing material composed of a metal mesh in which the ratio a / b of the space a between vertical strands to the space b between horizontal strands is less than 1, and light-transmitting reinforcing fibers arranged on one or both sides thereof. A reinforcing prepreg sheet impregnated with a curable resin. A prepreg sheet obtained by impregnating a reinforcing material made of a metal mesh in which the ratio a / b of the space a between vertical strands a and the space b between horizontal strands is less than 1 is impregnated with a photocurable resin is used as a reinforcing surface of a concrete structure. A method for reinforcing a concrete structure, characterized by winding or sticking, and curing the prepreg sheet by light irradiation. Light is applied to a reinforcing material composed of a metal mesh in which the ratio a / b of the space a between vertical strands to the space b between horizontal strands is less than 1, and light-transmitting reinforcing fibers arranged on one or both sides thereof. A method for reinforcing a concrete structure, characterized in that a prepreg sheet impregnated with a curable resin is wound or pasted on a reinforcing surface of a concrete structure, and the prepreg sheet is irradiated with light to be cured. Photo-curing to a reinforcing material comprising a first prepreg sheet obtained by impregnating a photo-curing resin into a reinforcing material made of a metal mesh, a metal mesh, and a light-transmitting reinforcing fiber disposed on one or both sides thereof. A second prepreg sheet impregnated with a conductive resin is laminated on a reinforcing surface of a concrete structure and wound or pasted, and each of the first and second prepreg sheets is irradiated with light and cured. Reinforcing method for concrete structures. 6. The concrete according to claim 3, 4 or 5, wherein a thermosetting resin sheet is attached and integrated on one side of the prepreg sheet, and the thermosetting resin sheet side is attached to a reinforcing surface of a concrete structure. How to reinforce a structure. 6. The concrete structure according to claim 3, 4 or 5, wherein after the thermosetting resin sheet is attached to the reinforcing surface of the concrete structure, the prepreg sheet is attached to the thermosetting resin sheet surface. Reinforcement method.

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