JP2001040819A - Method for reinforcing concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce a concrete structure by applying an adhesive resin on a surface of the concrete structure such as a beam, a column, and a wall, and sticking thereto a reinforcing fiber sheet. SOLUTION: A bundle of aramid fibers are twill-woven to form a tape-shaped reinforcing fiber sheet having a width of 30 cm, and a surface 2a of a concrete structure 2 is primed with an adhesive resin 10, followed by sticking the thus formed reinforcing fiber sheet 1 to the primed surface. After sticking the sheet 1, an external surface of the sheet 1 is rolled by a roller so as to be pressed onto the surface 2a, and therefore air voids between the fibers of the sheet 1 are removed, whereby the applied adhesive resin 10 is infiltrated into the fibers. Then, the adhesive resin 10 is faced on the external surface of the sheet 1, which is then rolled by the roller, and after hardening of the adhesive resin 10, the entire sheet 1 is positively combined with the surface 2a in one body. Therefore, the concrete structure can be reinforced by the reinforcing sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing a concrete structure such as a concrete pier or a pillar or wall of a building by attaching a reinforcing fiber sheet.

[0002]

2. Description of the Related Art Conventionally, as a method of shear reinforcement of a concrete structure, a primer is applied to a concrete structure a which has been subjected to a ground treatment for cracks and dirt removal as shown in FIG. 1 and an adhesive resin is applied. After that, a tape-shaped reinforcing fiber sheet b is wound and attached, the surface of the sheet b is rolled, an adhesive resin is applied, the resin is impregnated between the reinforcing fibers of the sheet b, and the adhesive resin is cured. A method is known in which a multi-layered reinforcing fiber layer is formed on the surface of the structure a, and a coating, a resin mortar, a cement mortar, a refractory coating material, or the like is applied thereon.

[0003]

An aramid fiber or a carbon fiber having a higher tensile strength than concrete is used for the reinforcing fiber sheet b, and the fiber bundle is woven into a plain weave or twill weave to form a sheet. When the fiber content is large, the sheet strength can be increased. However, if the amount of fibers is increased to obtain a large reinforcing strength, the amount of the undercoat adhesive resin for impregnating the reinforcing fibers of the sheet b must be increased, and the structure a and the sheet b must be integrated. Cannot be obtained, and the desired reinforcing effect cannot be obtained. In order to increase the amount of the undercoating adhesive resin, if the amount of coating on the peripheral surface of the structure a is increased, the dripping or dripping phenomenon occurs, and the workability is remarkably deteriorated. It is not preferable because the amount of liquid in the sagged portion is insufficient. Normally, the maximum amount of the adhesive resin that does not cause dripping is 0.5 to 0.6 kg in a commercially available adhesive resin.
/ M ² . Table 1 shows the relationship between the proof stress of the aramid fiber reinforcing fiber sheet b, the amount of fiber, and the amount of adhesive resin.
When the proof stress of the sheet b is 120 ft / m, the fiber amount is as large as 830 g / m ² and the amount of the undercoat adhesive resin is 0.72.
A large amount of kg / m ² is required, causing dripping. Table 1 Strength of the sheet (ft / m) 40 60 90 120 amount of fibers (g / m2) 280 415 623 830 undercoating adhesive resin amount ^{(kg / m 2) 0.36 0.48} 0.6 0.72 liquid dripping like In order to prevent this, an attempt was made to increase the viscosity by adding a thickener to the adhesive resin.
This impairs the impregnating ability of the sheet b, leaves air bubbles in the sheet, and reduces the insufficient adhesion of the sheet b to the structure a. Also, the sheet b was immersed in an adhesive resin solution, but the sheet b lost elasticity (shape retention), and was very troublesome to handle. Was not practical.

An object of the present invention is to provide a simple method for reinforcing a concrete structure using a reinforcing fiber sheet having a high yield strength and a large amount of fiber.

[0005]

According to the present invention, there is provided a reinforcing method for reinforcing a structure by adhering a reinforcing fiber sheet to the surface of a structure such as a concrete beam, a column or a wall. The above object is achieved by applying an adhesive resin to the inner surface of the reinforcing fiber sheet and applying the same to the inner surface of the reinforcing fiber sheet without impairing the shape retention of the reinforcing fiber sheet. I made it. The adhesive resin is permeated between the fibers of the reinforcing fiber sheet by rolling the surface of the bonded reinforcing fiber sheet without impairing the shape retention.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The case where the method of the present invention is applied to a columnar concrete structure will be described. In FIG. 2, reference numeral 1 denotes a twill weave of a bundle of aramid fibers and a width of 30.
cm shows a reinforcing fiber sheet (manufactured by Fivex Co., Ltd.) having a fiber amount of 830 g / m ² and a proof stress of 120 tf / m, and the reinforcing fiber sheet 1 has a ground treatment for repairing cracks and the like. Then, an adhesive resin 10 is applied to the surface 2a of the concrete structure 2 on which the primer and the putty have been applied, and then the primer is put on the surface. As the adhesive resin, for example, an epoxy resin impregnated adhesive of E2500 manufactured by Konishi Co., Ltd. is used, and when the sheet 2 is adhered, the epoxy resin impregnated adhesive is applied to the front surface 2a and the inner surface of the sheet 1 which is the adhered surface. I do. In this case, the fiber weight of 830 g / m ^2, although the adhesive resin of the undercoat should be applied to each side of 0.72 kg / m ² in a total amount not occur dripping or dropping the surface 2a leave applying 0.5 kg / m ² or less of the amount of degree, was stuck to the sheet 1 to the surface 2a by applying the amount of the remaining 0.22 kg / m ² to bonded wear surface of the sheet 1 . The sheet 1 maintained shape retention (elasticity enough to keep its original shape), and the sticking operation was easily performed. After adhering the sheet 1, the outer surface of the sheet 1 is pressed with a roller so as to press it against the surface 2 a (strengthen) to remove bubbles between fibers of the sheet 1, and the applied adhesive resin 10 penetrates. I do.
Thereafter, an adhesive resin is overcoated on the outer surface of the sheet 1 and similarly rolled with a roller, the adhesive resin penetrates from the outer surface of the sheet 1 into the inside thereof, and after the adhesive resin is cured, the entire sheet 1 is securely formed. The sheet 1 is integrated with the surface 2a, and the shearing force applied to the concrete structure 2 can be reinforced by the sheet 1. If necessary, the reinforcing fiber sheet 1 is applied in multiple layers.

The amount of the adhesive resin to be overcoated is such that the fiber amount is 83
In the case of 0 kg / m ² , it is about 0.5 kg / m ^2. After curing of the undercoat and overcoat adhesive resins, finish work such as painting, mortar coating, and fire protection coating is performed.

[0008] The results of testing the adhesion strength between the concrete structure and the fiber reinforced sheet according to the reinforcing method of the present invention are as follows. #Reinforcement fiber sheet with proof stress of 120f
An aramid fiber sheet (AK-120, manufactured by Fivex Co., Ltd.) 1 having a t / m and a fiber amount of 830 is prepared, and an adhesive resin (E2500, epoxy resin impregnated adhesive manufactured by Konishi Co., Ltd.) is provided on the sheet. 3 as an undercoat and FIG.
As shown in FIG. 4, a primer 4 and a putty 5 are applied to the surface of the concrete flat plate 3 of JIS A 5304 which has been subjected to a base treatment, and the sheet 1 is applied to the concrete flat plate 3 according to the method of the present invention. I wore it. After that, it is rolled with a roller and overcoated with the same adhesive resin,
After these adhesive resins are cured, cuts 6 are made in three places of the sheet 1, and attachments 7 of the metal fittings are attached to the cuts 6 to form test pieces, and a test machine (Yamamoto Lifting Machine Co., Ltd.) Manufactured by LPT-1500). The adhesive resin is applied at a rate of 0.2 kg / m ² on the surface of the sheet 1 and 0.5 kg / m ² on the surface of the concrete plate 3.
m ² was applied. The measurement result was 3.20 N / mm ² ,
It was 2.82 N / mm ² and 3.90 N / mm ² .

For comparison, the undertreated concrete
0.7 kg / m^TwoApply
After applying the sheet 1 by a conventional method and rolling it,
0.5kg / m as top coat^TwoBy applying
When a test piece was prepared and its adhesion strength was measured, 1.0
5N / mm^Two, 1.22 N / mm^Two, 0.89 N / mm ^Two
Met.

In the above description, the case where the reinforcing fiber sheet 1 is made of aramid fiber has been described. However, the reinforcing fiber sheet may be a carbon fiber or a mixed fiber of aramid fiber and nylon fiber.

[0011]

As described above, according to the present invention, the surface of the concrete structure and the inner surface of the reinforcing fiber sheet adhered to the surface of the concrete structure are primed with an adhesive resin to give the sheet a shape-retaining property. As it is made to adhere, the reinforcing fiber sheet with a large amount of fiber can be attached without causing dripping, etc. There are effects such as being able to do.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a conventional method for reinforcing a concrete structure.

FIG. 2 is a perspective view showing an embodiment of the present invention.

FIG. 3 is an explanatory view of a method for measuring the adhesion strength of a reinforcing fiber sheet according to the method of the present invention.

FIG. 4 is an enlarged sectional view taken along line 4-4 in FIG. 3;

[Explanation of symbols]

1 Reinforcing fiber sheet, 2 Concrete structure, 2a
Surface, 10 adhesive resin,

Claims (2)

[Claims] 1. A reinforcing method for reinforcing a structure by adhering a reinforcing fiber sheet to a surface of a structure such as a beam, a column, or a wall made of concrete. A method for reinforcing a concrete structure, characterized in that an adhesive resin is also applied to the inner surface of a reinforcing fiber sheet and is adhered to the reinforcing fiber sheet without impairing the shape retention of the reinforcing fiber sheet. 2. The concrete according to claim 1, wherein the surface of the reinforcing fiber sheet adhered without impairing the shape-retaining property is rolled, and the adhesive resin is permeated between the fibers of the sheet. How to reinforce structures.