JP3220540B2 - Concrete repair method using unidirectional reinforced fiber sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention repairs a concrete surface by fitting a reinforcing fiber sheet having reinforcing fibers arranged in one direction to a concrete repair surface, impregnating the reinforcing fiber with a matrix resin and curing the resin. More particularly, the present invention relates to a concrete repair method capable of improving the adhesive strength of a reinforcing fiber sheet to a concrete surface and increasing repair strength.

[0002]

2. Description of the Related Art In recent years, piers such as bridges and elevated roads have been repaired with fiber reinforced plastic. As described in JP-A-3-222934, JP-A-3-224901, etc., the applicant of the present invention has been able to carry out repair with good workability at the repair site and improve the strength after repair. A reinforced fiber sheet for repair was proposed. FIG. 4 shows the outline of the unidirectionally reinforced fiber sheet.

[0003] That is, the reinforcing fiber sheet 1 is
And a support 2 provided with an adhesive layer 3
The reinforcing fibers 4 are arranged and bonded in one direction on the upper side. The reinforcing fiber sheet 1 is cured after impregnating the reinforcing fibers 4 with a matrix resin at a repair site such as a bridge or an elevated road, and is applied to a repair surface.

The reinforcing fibers 4 on the reinforcing fiber sheet 1 are impregnated with the matrix resin before the sheet 1 is attached to the repair surface, or the matrix resin is applied to the repair surface. The sheet 1 is attached and pressed thereon, whereby the matrix resin is impregnated into the reinforcing fibers. In order to further improve the impregnation of the matrix resin into the reinforcing fibers, the support 2 of the reinforcing fiber sheet 1 is made of a glass fiber cloth sheet or the like, and the reinforcing fiber sheet 1 is attached to the repair surface. After that, a matrix resin is applied from the support 2 side to impregnate the reinforcing fibers with the matrix resin.

[0005]

However, according to the results of research conducted by the inventors of the present invention, the repair surface is a concrete surface of a bridge or an elevated road, and the length of the reinforcing fiber is not sufficiently large. In the case of a reinforcing portion where the area for application of the sheet cannot be sufficiently secured, even if the reinforcing fiber sheet 1 is attached to the concrete surface by any of the above methods, as shown in FIG. When a bending stress is applied in the M direction, first of all, one end of the reinforcing fiber sheet 1 is peeled off due to a shear stress generated on an adhesive surface between the concrete repair surface 5a of the beam 5 and the reinforcing fiber sheet 1. After that, it was found that this peeling spread to the entire reinforcing fiber sheet 1 and the reinforcing effect by the reinforcing fiber sheet 1 was rapidly reduced.

Accordingly, an object of the present invention is to provide a unidirectionally reinforced fiber sheet for repairing a structure such as a bridge or an elevated road, even when a sufficient area for application cannot be secured. It is an object of the present invention to provide a concrete repair method capable of improving the adhesive strength of the concrete to the repair surface and increasing the repair strength.

[0007]

The above object is achieved by a method for repairing concrete using a unidirectionally reinforced fiber sheet according to the present invention. In summary, the present invention relates to a method for repairing a concrete surface by fitting a reinforcing fiber sheet having reinforcing fibers arranged in one direction to a concrete repair surface, impregnating the reinforcing fiber with a matrix resin and curing the resin. The reinforcing fibers located at both ends of the fiber sheet
A groove is formed in the concrete surface in a direction perpendicular to the axis, and the groove is filled with resin to be suitable for the concrete repair surface.
Both ends located above the groove of the combined reinforcing fiber sheet
Is bonded to the resin filled in the groove, and is a method for repairing concrete using a unidirectionally reinforced fiber sheet. Preferably, an end of the reinforcing fiber sheet located in the groove is folded into a groove filled with resin.

[0008]

FIG. 1 shows an embodiment of a repair method according to the present invention. In this embodiment, a cross section showing a case where a beam 5 or the like is repaired using a unidirectionally reinforced fiber sheet 1 is shown. FIG.

The unidirectionally reinforced fiber sheet 1 used in the present invention may be of any configuration.
As shown in FIG. 4, it is composed of a support 2 and reinforcing fibers 4 which are arranged and bonded in one direction on the support 2 via an adhesive layer 3.

The support 2 is made of various materials such as scrim cloth, glass paper, glass non-woven fabric, glass fiber cloth, polyamide, PPS (polyphenylene sulfide), etc. in order to improve the impregnation of the matrix resin into the reinforcing fibers 4 during repair. It is preferable to use a polymer nonwoven fabric or the like.

The adhesive for forming the adhesive layer 3 may be any as long as the reinforcing fibers 4 can be temporarily bonded to the support 2 in principle. Preferably, the adhesive is compatible with the matrix resin. It is preferable to use a resin having good solubility. For example, when using an epoxy resin as the matrix resin, it is preferable to use an epoxy adhesive.
The adhesive layer 3 may have a thickness of about 1 to 50 μm, preferably about 3 to 20 μm, as long as the reinforcing fibers 4 can be temporarily bonded to the support 2.

The reinforcing fibers 4 include pitch-based carbon fibers,
Various fibers such as boron fiber, PAN-based carbon fiber, aramid fiber, glass fiber, steel fiber, polyester fiber, and polyethylene fiber can be used. These fibers can be used alone or in combination of two or more kinds to be used as hybridized fibers.

The reinforcing fibers 4 are lightly disintegrated by arranging a large number of fiber bundles or lightly twisted and converged fiber bundles on the adhesive layer 3 and crushing them from above, using the filaments as filaments. Thereby, the reinforcing fibers 4 are bonded and arranged in one direction via the adhesive layer 3 on the support 2 in a state where the reinforcing fibers 4 are stacked in a plurality of layers by a binding agent or a twist.

Such a unidirectionally reinforced fiber sheet 1
As shown in FIG. 1, a matrix resin is applied to a reinforcing fiber 4 of a reinforcing fiber sheet 1 by an appropriate application means such as a roller, a brush, or a spray at a repair site of a building such as a bridge or an elevated road. Then, the reinforcing fiber 4 is adhered to the concrete surface to be repaired with the side of the reinforcing fiber 4 as the repaired portion side of the structure. If necessary, the desired number of reinforcing fiber sheets 1 are laminated. Preferably, the impregnation operation of the matrix resin is performed with a hand roller or the like from the side of the support 2 every time of lamination. Thereafter, a cover is formed thereon, and then the matrix resin is cured by being left as it is or by heating.

As described above, the reinforcing fiber sheet 1 of the present invention
Is used by impregnating the reinforcing fiber 4 with the matrix resin at the repair site when used for repair, but it is possible to cure the matrix resin by leaving the sheet 1 as it is after attaching the sheet 1 to the repair location. In order to achieve this, it is preferable to use a room-temperature-curable resin as the matrix resin.

As the room temperature-curable resin, an epoxy resin, an unsaturated polyester resin, or the like, which can be cured at room temperature by adjusting the combination of a curing agent and a curing accelerator, can be used.

As another method, a room-temperature-curable matrix resin is applied to the repair site to a thickness of, for example, about 100 μm, and then the reinforcing fiber sheet 1 is attached with the reinforcing fiber 4 side as the repair site side. If necessary, the desired number of reinforcing fiber sheets 1 are subsequently laminated in the same procedure, and finally the reinforcing fibers 4 are impregnated with the matrix resin 30 from the support 2 side. Further, at this time, every time the sheets 1 are laminated, the reinforcing fibers 4 can be impregnated with the matrix resin from the support 2 side. Thereafter, similarly to the above, the cover is performed on the sheet 1 and then left as it is to cure the matrix resin.

According to the present invention, when performing the repair work using the reinforcing fiber sheet 1, first, as shown in FIGS. 1 and 2, the concrete surface to be repaired is located at both ends of the reinforcing fiber sheet. Grooves 10 are formed in the concrete surface along both edges of the reinforcing fiber sheet, that is, in a direction perpendicular to the axis of the reinforcing fiber.

The width W and the depth D of the groove 10 can be arbitrarily set. Generally, the width W is 5 to 30 mm, usually about 8 mm, and the depth D is 5 to 10 mm, usually It is about 8 mm. What is important in the present invention is that both end portions of the reinforcing fiber sheet 1 are located on the grooves 10. In other words, in order to effectively carry out the present invention, both end portions of the reinforcing fiber sheet 1 are required. The protrusion amount ΔW into the groove 10 needs to be at least 2 mm or more. Also, the cross-sectional shape of the groove 10 may be a U-shape as shown in the figure,
A rectangular cross section can also be used. Further, the width H of the groove 10 is
Although it can be the same as the width h of the reinforcing fiber sheet 1,
For example, it is desirable to increase the size by about 10 to 20 mm.

Further, in the present invention, the resin 11 is provided in the groove 10.
Is filled. As the resin 11, any resin can be used as long as it has a large adhesive force to both ends of the reinforcing fiber sheet 1. Preferably, a resin having good compatibility with the matrix resin is used. For example, when an epoxy resin is used as the matrix resin, it is preferable to use an epoxy adhesive or the like. Further, unsaturated polyester resins, vinyl ester resins, urethane resins, and the like can be used.

Further, according to another embodiment of the present invention, FIG.
As shown in (2), the end of the reinforcing fiber sheet located in the groove 10 can be folded into the groove filled with the resin 11. In this case, the fold amount of the end of the reinforcing fiber sheet ΔL
Is 5 to 30 mm, usually about 8 mm.

The present inventors produced a reinforced fiber sheet 1 using carbon fibers as the reinforcing fibers 4 and a glass fiber cloth sheet as the support 2. The carbon fiber yarn weight was 175 g / m ² . The reinforcing fiber sheet had a length of 135 mm and a width of 150 mm, and the reinforcing fibers were arranged in the longitudinal direction.

The test piece had a thickness of 50 mm, a width of 150 mm,
A groove 10 having a width of 400 mm, a rectangular section, and a width W × depth D × length H = 8 × 8 × 150 mm was formed at a center-to-center distance of 135 mm.
Therefore, the protrusion amount ΔW of the reinforcing fiber sheet 1 into the groove 10 at both ends was 4 mm.

The concrete surface 5a to which the reinforcing fiber sheet 1 was attached was sanded, and then a primer was applied to perform a base treatment. Thereafter, a reinforcing fiber sheet 1 impregnated with a matrix resin was attached to the concrete surface. Epoxy resin was used as the matrix resin. The epoxy adhesive 11 was filled in the groove 10 formed on the concrete surface.

As shown in FIG. 6, the test piece was supported on fulcrums separated by 300 mm from each other, and a pressing load P was applied to the center of the test piece.

In the conventional repair method shown in FIG. 5, when the pressing load P is 850 Kg and the deformation is 0.45 mm, a crack is generated at the center of the test piece S, and at the same time, the reinforcing fiber sheet 1 is removed from one end. It peeled off, and the reinforcing effect by the sufficient reinforcing fiber sheet 1 was not obtained.

On the other hand, according to the repair method of the present invention shown in FIG. 1, a crack began to be generated at the center of the test piece S when the pressing load P was 850 Kg and the deformation amount was 0.45 mm. Did not lead. When the pressing load was further increased, the test piece S was broken from the center at a pressing load P of 1020 kg and a deformation of 0.8 mm. However, both ends of the reinforcing fiber sheet 1 did not peel off from the concrete surface, and the repair strength was increased by about 20% as compared with the conventional repair method.

In addition, according to the repair method of the present invention shown in FIG. 3 , as in the previous case, a crack starts to be generated in the central portion of the test piece S when the pressing load P is 850 Kg and the deformation is 0.45 mm. However, when the pressing load was further increased without causing brittle fracture, the test piece S was broken from the center at a pressing load P of 1100 Kg and a deformation amount of 0.9 mm. However, both ends of the reinforcing fiber sheet 1 did not peel off from the concrete surface, and the repair strength was increased by about 30% as compared with the conventional repair method.

[0029]

As described above, according to the method for repairing concrete using the unidirectionally reinforced fiber sheet according to the present invention, the shaft of the reinforcing fiber is positioned at both ends of the reinforcing fiber sheet.
A groove is formed in the concrete surface in a direction perpendicular to the line, and this groove is filled with resin to fit the concrete repair surface
Both ends located above the groove of the reinforced fiber sheet are
It is bonded to the resin filled in the groove, and preferably, since both ends of the reinforcing fiber sheet are folded into the groove, the bonding strength of the reinforcing fiber sheet to the concrete repair surface is improved, and as a result, the repair effect is increased. I do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of a concrete surface repair method according to the present invention.

FIG. 2 is a view of the concrete surface repairing method according to an embodiment of the present invention as viewed from below in FIG. 1;

FIG. 3 is a sectional view for explaining another embodiment of the concrete surface repairing method of the present invention.

FIG. 4 is a diagram illustrating one embodiment of a reinforcing fiber sheet that can be used in the present invention.

FIG. 5 is a view for explaining a conventional concrete surface repair method.

FIG. 6 is a perspective view illustrating a reinforcing test method using a test piece.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reinforcing fiber sheet 2 Support 3 Adhesive layer 4 Reinforcing fiber 5 Reinforced object 10 Groove 11 Filling resin

Claims (2)

(57) [Claims] 1. A method for repairing a concrete surface by fitting a reinforcing fiber sheet having reinforcing fibers arranged in one direction to a concrete repair surface and impregnating the reinforcing fiber with a matrix resin and curing the same. Direction perpendicular to the axis of the reinforcing fiber
A groove is formed in the concrete surface, resin is filled in the groove, and a reinforcing fiber sheet adapted to the concrete repair surface
Resin filled in the grooves at both ends located above the grooves
A method for repairing concrete using a unidirectionally reinforced fiber sheet, characterized by being adhered to a concrete sheet. 2. The method for repairing concrete with a unidirectionally reinforced fiber sheet according to claim 1, wherein an end of the reinforcing fiber sheet located in the groove is folded into a groove filled with resin.