JPH05141064A - Reinforcing structure for concrete construction - Google Patents

Abstract

PURPOSE:To prevent a concrete construction or easecially a conventional concrete construction by use of reinforcing bars from aging and to reinforce a concrete construction which already has aged. CONSTITUTION:Exposed surfaces of posts and walls in a concrete construction are coated with a fiber-reinforced resin sheet 2 or a fiber-reinforced resin panel. In the case of the sheet 2, a post 1 is wounded up by it and a wall face is coated with it by sticking thereon. In some cases, an appropriate coating is applied on the sheet 2. In the case of the panel, a covering panel is formed in accordance with the objective structure and it is fitted thereto. After that, reinforcing materials such as cement and adhesive may be charged with pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reinforcing concrete structures, and more particularly to a technique for improving the compression and tensile properties of concrete structures.

[0002]

2. Description of the Related Art Conventionally, concrete structures use reinforcing bars as reinforcing members. As is well known, concrete is an extremely brittle material such as weak tensile strength and lack of elasticity. Therefore, by using an iron material that can complement the strength characteristics, a more economical structure having excellent strength is constructed.

However, the conventional structure using reinforcing bars has the following problems. First, a problem in constructing a structure is a reduction in work efficiency due to the weight of the reinforcing bar itself. Iron is difficult to carry and carry because of its weight. The larger the structure, the more human and time-consuming it takes to carry the reinforcing bar, and this problem is ultimately reflected in the construction cost. Also, as the weight increases, work accidents become a serious consequence. Furthermore, as the structure becomes larger, the amount of iron used also increases, which synergistically increases the weight of the entire structure, complicating strength calculation and work-related estimation calculation, and as planned. Hinder the progress of work.

Second, there is a problem of deterioration of the structure after construction. The cause is basically the oxidation of iron and the accompanying cracking of concrete. Of course, various attempts have been made to prevent the corrosion of the reinforcing bars. For example, it is common practice to prevent the corrosion of the reinforcing bars by applying an epoxy-based rust preventive on the surface of the reinforcing bars. But,
Except when the rust preventive agent is applied very carefully, corrosion starts from scratches (or uneven coating) on some coating layers and gradually spreads to the whole corrosion. In reality, the painting cost is too bulky to meet the construction cost. In particular, as in today's situation where regulations on national land development are increasing due to local regulations and administrative guidance, it is difficult to freely collect the granular sand used for the coarse aggregate of concrete, and therefore many concrete structures are used. In the case of, there are less regulated beach sands,
That is, sea sand is used. Sea sand probably contains salt. The reinforced steel frame, which is a reinforcing material for concrete, further increases the degree of corrosion due to the salt content of the concrete, and the concrete itself is eroded to generate cracks. And today's problem, acid rain, penetrates through cracks in concrete and destroys concrete, that is, alkaline structure.

[0005]

Therefore, the present applicant has proposed a new concrete technique for solving such a problem (Japanese Patent Application No. 3-216242). This is basically to mix chopped fibers of fiber reinforced resin or spherical or square particles into cement to strengthen concrete after cement solidification. Is formed and cement is driven into this module to construct a structure without using reinforcing bars. However, as a pre-stage process in which this new concrete technology (technology that does not use rebar) is generally popularized, among various existing reinforced concrete structures, those that are progressing deterioration are There is still plenty of room for reinforcement.

Therefore, an object of the present invention is to reinforce a concrete structure, in particular, a conventional concrete structure using a reinforcing bar as a reinforcing material very easily and economically.

[0007]

[Means for Solving the Problems] In order to achieve the above object and achieve the object, the concrete reinforcing structure according to the present invention coats the concrete surface with a fiber reinforced resin.

[0008]

FUNCTION The fiber reinforced resin (FRP) can exert excellent properties in terms of tensile strength and elasticity against metals having the same thickness. For example, the relationship between strength / specific gravity and elastic modulus / specific gravity of glass fiber or carbon fiber, which is a typical material of fiber-reinforced resin, is as shown in FIG. 4 (new material technology &application;Ohmsha; see) When molded, the weight of the fiber-reinforced composite resin is overwhelmingly lighter than that of the reinforced steel frame, and it is strong in tension and exhibits excellent properties.
Moreover, the fiber reinforced resin has an acid resistance function.

The problems in the concrete structure are compressive elasticity and tensile stress. By the way, in the case of pure glass fiber, the tensile strength shows about the same strength as an iron wire of the same thickness, but it has a weakness that it lacks elasticity.To compensate for this defect, a plastic such as polyester is used as a binder for fiber reinforced resin ( FRP) increases the strength against bending several tens of times and can be used as a concrete reinforcing material to replace iron. The tensile strength and elasticity of these FRPs are shown in Fig. 5 (reference materials are the same as above). These advantages in compressive elasticity and tensile stress are not limited to glass fiber, but carbon fiber, boron fiber, other currently known silicon carbide fiber, aramid fiber, etc. are similar, but they are overwhelmingly superior to iron. Due to their superior performance, those which are as cost-effective as possible, for example glass fiber composites, are considered as iron-alternatives.

As described above, the fiber reinforced resin has extremely excellent properties in strength as compared with the conventional reinforced steel frame, and when the surface of the concrete structure is coated with the fiber reinforced resin as in the present invention, It is possible to provide a reinforced structure in which the so-called "fog" portion of the reinforced concrete structure is omitted. That is, the fiber-reinforced resin (panel or sheet) acts like a conventional reinforcing bar, and reinforces and protects the concrete structure on the surface against axial load, bending and bending. In addition, the fiber-reinforced composite resin is lightweight and has corrosion resistance and acid resistance, and thus reliably protects the surface of the conventional reinforced concrete structure from corrosion.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention, in which a concrete strut 1 is provided with a fiber reinforced resin sheet,
For example, it is covered with the glass reinforced resin sheet 2.
Incidentally, reference numeral 3 is concrete, and 4 is rebar.

Although there are many pillars conventionally made of concrete, such as piers for expressways and pillars for buildings, due to the cracking of concrete due to the oxidation of reinforcing bars,
Currently, there are quite a number of structures that require repairs throughout the country. Conventionally, these have been treated by a method of injecting resin from the surface layer, but the original strength of the structure cannot be maintained only by injecting the resin. This is because the reinforcing resin does not surely invade each part of the crack but merely restores the concrete layer near the surface.

Therefore, the resin sheet 2 is provided on the concrete surface.
Wrap around. At the time of winding, an adhesive, a driving pin, or other fixing means may be used. The simplest way is to wind the resin sheet 2 while applying the adhesive, but in the case of further surface treatment, the fiber reinforced resin (liquid)
Is applied or sprayed to form a smooth surface coating layer. The resin sheet 2 exerts a stress greater than that of the reinforcing bars against various loads applied to the support columns 1 and strengthens and protects the structure. This is as follows.

First, the invasion of acid rain or the like that damages the concrete 3 can be completely prevented on the concrete surface. Further, this resin sheet 2 functions as a reinforcing material for compression and tension with respect to the concrete surface layer. Although the resin sheet 2 is very thin, when it is wound around the surface of a structure such as the concrete support column 1, it is possible to sufficiently reinforce the weak points of the concrete relating to tension.

That is, the reinforcing bars 4 in the conventional concrete structure have the meaning of complementing the tensile strength of the concrete 3, but since the reinforcing bars 4 cannot be exposed on the surface, a so-called "fog" is provided. A concrete layer 3b is formed on the surface. However, this "fog"
In many cases, 3b is not exactly as designed on the actual construction site, and is considered only for the purpose of simply decorating the exterior of the building. In short, the concept of "fog" in reinforced concrete structure is the calculation of the surface thickness for decoration on the premise of reinforcing the reinforcing bar, and since the reinforcing bar 4 has the tensile stress in the first place, the "fog" of concrete is originally There is no inconvenience without it.

The reinforcing technique of winding the fiber reinforced resin sheet 2 abandons the conventional concept of "fog" and is based on the idea of exposing the concrete reinforcing material (resin sheet) to the concrete surface layer. This is a concept that did not occur in conventional concrete structures with supplementary reinforcing bars, and as a result, the concrete surface layer can be decorated, protected from acid rain, and the structure can be reinforced against load. As a matter of course, the fiber-reinforced resin has a free color scheme and paint, and it is easy to fix decorative tiles.
It has the property of being impermeable to water and strong in tension. If such a resin sheet 2 is used, it is possible to enhance protection of all concrete structures, such as reinforcement of bridge piers and columns by winding, reinforcement of wall surface and floor surface by attachment. Needless to say, the resin sheet used in this case is not limited to the glass fiber reinforced resin.

FIG. 2 shows a fiber reinforced resin panel 7 for reinforcing an existing concrete wall surface 6 such as a sound insulation wall of a highway or the like. This is based on the idea of the fiber reinforced resin module (Japanese Patent Application No. 3-216242) previously proposed by the present applicant, and for the purpose of reinforcing an existing old building, a resin panel form 7 having a predetermined shape is used. For example, it is fitted to the sound insulation wall 6, and the lower part of the resin panel form 7 is securely fixed by an appropriate means, for example, bolt fixing, adhesion or heat welding. Of course, an appropriate reinforcing agent such as an adhesive, concrete, or an adhesive-concrete mixture may be injected from an appropriate place on the side surface of the mold 7 and pressure-fed to reinforce the wall surface. The panel formwork 7 using the fiber reinforced resin can reinforce concrete against bending and tension and prevent acid rain from entering, like the resin sheet 2 described above.

The resin panel frame 7 is applied to a place where the resin sheet 2 cannot be wound and the work can be performed more easily than pasting the sheet. The thickness of the panel 7 does not matter.
This is because the fiber-reinforced resin sufficiently functions as a concrete reinforcing material even if it is thin, and therefore it is not always necessary to make it thick. Regarding the strength characteristics when the concrete structure is covered with the resin sheet, the applicant is currently accumulating data, so detailed experimental data will be corrected and added at a later date.
Incidentally, according to the currently known data, when the concrete specimen was coated with nylon paper, the tensile strength of the test piece reached 20% of the compressive strength.

On the other hand, such a resin panel frame 7 is not a single panel made of a single material, but may be constructed by sandwiching an intermediate material 10 such as expanded polystyrene or sponge rubber as shown in FIG. In addition, 11 is a fiber reinforced resin panel. This intermediate material 10 can change the performance properties of the resin panel 11 depending on the use place. For example, in the case of a general building, it is made to function as a heat insulating material or a sound insulating material, and for the purpose of preventing the influence of radon emitted from concrete such as a basement. ,
It is also possible to sandwich a radiation shielding material containing a lead substance. Although it is a special case, water may be sealed or water may be pumped by connecting a pipe to an external pump. When a fire occurs in a building room or in a tunnel, the resin panel on the wall (or ceiling) begins to melt and the pumped water spouts to extinguish the fire source.

The reinforcing technique described above is not limited to the structure to be applied. The present invention can be applied not only to existing reinforced concrete, but also to concrete structures (limited to those whose surface is not resin-coated) mixed with a fiber reinforced resin substance previously proposed by the present applicant.

In particular, when the resin panel is arranged on the concrete surface and cement or other suitable reinforcing substance is pressed in from the side surface (including the upper surface or the lower surface), an opening is provided at an appropriate position of the covering panel, After mixing the substance, it is desirable to close the opening with an appropriate panel material. The closing lid may or may not be the same material as the wall panel material. Further, in the case of repairing the wall surface, the opening position is not limited to the wall surface side portion, the bottom surface, the upper surface, and other setting positions, and the numerical aperture is free.

[0022]

INDUSTRIAL APPLICABILITY As described above, the concrete reinforcing structure according to the present invention is a structure in which a fiber reinforced composite material (sheet or panel) is wound around, adhered or fitted on the surface as a reinforcing material for a concrete structure. Therefore, it is possible to provide a reinforcing structure in which the so-called "fog" portion in the conventional reinforced concrete structure is omitted. In other words, the fiber reinforced resin has a function similar to that of the conventional reinforcing bar and reinforces and protects the concrete structure against compression and tension. Further, the fiber-reinforced composite resin can surely protect the concrete surface because it has corrosion resistance and acid resistance.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of reinforcing concrete according to the present invention.

FIG. 2 is a diagram showing another example of reinforcement of concrete according to the present invention.

FIG. 3 is a diagram showing a structural example of a resin panel according to the present invention.

FIG. 4 is a graph showing general performance of FRP.

FIG. 5 is a graph showing general performance of FRP.

[Explanation of symbols]

 1 Concrete prop 2 Resin sheet 3b Cover 7 Resin panel formwork 10 Intermediate material

Claims (4)

[Claims] 1. A reinforcing structure for a concrete structure, characterized in that concrete is coated with a fiber reinforced resin. 2. The reinforcing structure for a concrete structure according to claim 1, wherein the fiber reinforced resin is a thin film sheet material. 3. The reinforcing structure for a concrete structure according to claim 1, wherein the fiber reinforced resin is a panel material formed into a predetermined shape. 4. The reinforcing structure for a concrete structure according to claim 3, wherein the panel material has a double structure, and an intermediate material is sandwiched therebetween.