JPH11148230A - Repairing or reinforcing method for concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sufficient repairing and reinforcing ability of a carbon sheet by eliminating a cavity between the carbon sheet and a concrete surface. SOLUTION: A carbon sheet 12 impregnated with thermosetting resin is mounted on a concrete structure while being heated to repair or reinforce the concrete structure. A holed separate film 13 in which a number of small holes are made is laminated on the carbon sheet 12, a continuously porous shock absorbing member 14 is laminated thereon, these are sealed by a sealing sheet 15, air in the sealing sheet is sucked while heating and hardening the thermosetting resin with proper heating means and the carbon sheet is adhered and fixed to the surface of a concrete body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing or reinforcing a concrete structure, and more particularly to a method for forming a carbon fiber prepreg sheet (a carbon fiber assembly is impregnated with a thermosetting resin such as an epoxy acrylate resin into a sheet). thing)
The present invention relates to a method for repairing or reinforcing a concrete structure, in which a concrete structure is attached to the surface of a concrete body to repair or reinforce the same.

[0002]

2. Description of the Related Art For the purpose of earthquake resistance, reinforcement, etc., columns, beams, floor slabs,
2. Description of the Related Art A construction method is known in which a carbon fiber prepreg sheet (carbon sheet) is attached to or wound around a concrete body such as a wall to reinforce the structure. FIG. 5 is an example in which a carbon sheet CS is attached to the surface of a concrete body for column reinforcement, beam reinforcement, and slab reinforcement of a building structure.
Fig. 6 shows carbon sheet C for reinforcing the lining of the tunnel.
FIG. 7 shows an example in which a carbon sheet CS is attached to the surface of a concrete skeleton to reinforce a slab, an overhang slab, and a pier of a bridge.

In this method, (1) ground treatment such as polishing and removal of a degraded layer on the concrete surface and repair of cracks, and (2) an adhesive or epoxy-based primer is applied to the concrete surface. (The process is not always necessary.) (3) After drying the primer, correct unevenness such as filling with epoxy putty, and (4) press and fix the carbon sheet against the surface of the concrete body while heating it with appropriate means. That is, by heating, the thermosetting resin impregnated in the carbon sheet is thermoset to fix the carbon sheet on the concrete surface. However, with such a method, it is difficult to uniformly press the carbon sheet against the concrete surface, and furthermore, the surface of the concrete skeleton originally has irregularities and cannot be removed by polishing. As described above, in the conventional method, the carbon sheet does not adhere to the concrete surface, and a gap is formed between the two or between the carbon sheet and the primer or the adhesive. When such voids occur, the effect of repair and reinforcement by the carbon sheet is reduced.

Therefore, in order to adhere and fix the carbon sheet to the concrete surface, it has been proposed to seal the carbon sheet in predetermined areas and vacuum-evacuate the inside of the seal to eliminate voids (Japanese Patent Laid-Open Publication No. Hei 1 (1994)). -197532). FIG.
FIG. 2 is an explanatory view of the proposed method of closely attaching a carbon sheet, wherein 1 is a concrete slab, 2 is an adhesive or primer applied to the surface of the concrete slab, 3 is a carbon sheet, and 4 is an outer surface of the carbon sheet 3. A bleeder cloth, 5 is a release film laminated on the bleeder cloth, 6 is a resilient flat electric heater, 7 is a metal foil sandwiching the flat electric heater, 8 is a bag film, and the carbon sheet 3 or the bleeder. Cross 4,
One that covers the release film 5 and the planar electric heater 6;
9 is the outer periphery of the bag film 8 and the concrete slab 1
It is a sealant tape provided between the surfaces to keep the airtight between them. When the air between the bleeder cloth 4 and the bag film 8 is sucked in vacuum by a vacuum pump (not shown) in the illustrated state, the carbon sheet 3 is pressed against the surface of the concrete slab 1 and simultaneously heated by the electric heater 6.

[0005]

In the vacuum suction method with heating, the carbon sheet violently undulates inside the hermetic seal, so that the carbon sheet cannot be uniformly adhered to the concrete surface, and voids cannot be removed. That is,
In the conventional vacuum suction method with heating, air is not suctioned uniformly over the entire sealed area, and the carbon sheet is wavy and does not adhere evenly to the concrete surface, so that voids cannot be eliminated. From the above, it is an object of the present invention to uniformly suction air over the entire sealed area, thereby making the carbon sheet uniformly adhere to the concrete surface, eliminating the gap between the carbon sheet and the concrete surface, and repairing and reinforcing with the carbon sheet. It is to be able to fully demonstrate the ability.

[0006]

According to the present invention, there is provided a carbon sheet impregnated with a thermosetting resin, which is formed by laminating a perforated release film having a number of small holes formed thereon. The continuous pore porous buffer member is laminated, the sheet, the film, and the buffer member are sealed with a sealing sheet, and while the thermosetting resin is cured by heating, the air in the sealing sheet is sucked, and the carbon sheet is converted into concrete. This is achieved by attaching to the surface of the building. That is, by laminating a perforated release film having a number of small holes formed on a carbon sheet, and laminating a continuous porous porous buffer member thereon, and vacuum-suctioning the film, the gap between the carbon sheet and the concrete surface is reduced. The air and the carbon sheet itself are uniformly sucked over the entire surface through the small holes of the perforated release film and the continuous pores in the continuous pore porous buffer member, and the voids are eliminated. That is, since the continuous pore porous cushioning member (nonwoven fabric) is pressed uniformly over the perforated release film by the vacuum suction operation, the sheet does not violently undulate,
Air is sucked uniformly. As a result, there is no fear that air pools remain, and air is properly suctioned over the entire sealed area, and concrete and the carbon sheet are uniformly adhered over the entire surface. .)

[0007] According to the present invention, the above object is also achieved by laminating an expanded porous polytetrafluoroethylene sheet (ePTFE sheet) on a carbon sheet impregnated with a thermosetting resin, and sealing these sheets with a sealing sheet. Then, while the thermosetting resin is cured by heating, the air in the sealing sheet is sucked, and the carbon sheet is attached to the surface of the concrete body. That is, heating with the ePTFE sheet laminated on the carbon sheet,
Since the air is sucked, the air is not locally sucked and remains, and the air in the entire area is sucked evenly through the continuous pores of the ePTFE, whereby the carbon sheet and the concrete surface adhere to each other. At the same time, the matrix resin (thermosetting resin) of the carbon sheet is melted by heating and e
It penetrates into the network structure of the PTFE sheet, and the carbon sheet and the ePTFE sheet adhere and integrate. As is well known, ePTFE exhibits excellent weather resistance, and particularly, prevents deterioration of ultraviolet rays, so that deterioration of the carbon sheet is prevented, whereby the reinforced concrete skeleton can stably secure strength for many years.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (a) First Embodiment FIG. 1 is an explanatory view of a first embodiment of a method for repairing or reinforcing a concrete structure according to the present invention, and FIG. 1 (a) shows concrete walls and floor slabs. FIG. 1B shows an example of a flat surface installation in which a carbon sheet is attached to a surface such as the one shown in FIG. In the figure, 11 is concrete, 12 is a carbon fiber prepreg sheet impregnated with a thermosetting resin (carbon sheet), 13
Is a perforated release film having many small holes formed therein (for example, a perforated sheet having a large number of small holes formed in a food packaging wrap film), and 14 is a continuous porous porous cushioning member such as a sponge (nonwoven fabric) ) And 15 are sealing sheets for sealing the sheet 12, the film 13, and the cushioning member 14,
Reference numeral 16 denotes a seal provided between the outer periphery of the sealing sheet 15 and the surface of the concrete 11 to keep the space therebetween airtight. Note that an adhesive or a primer is appropriately applied to the concrete surface.

When mounting the carbon sheet, (1)
First, ground treatment such as polishing and removal of the deteriorated layer on the concrete surface, repair of cracks, etc. is performed. (2) Then, an adhesive or epoxy primer is applied to the concrete surface, and (3)
After drying the primer, make unevenness correction such as filling with epoxy putty. (4) After that, the carbon sheet 12 is attached or wrapped around the concrete surface to be repaired and reinforced, and (5) The release film 1 with a hole is formed on the carbon sheet.
3 and a continuous porous porous cushioning member (non-woven fabric) 14 is laminated thereon.
Then, the outer periphery of the sealing sheet 15 and the surface of the concrete slab 11 are sealed with a seam 16 to make the inside of the sealing sheet airtight. (7) Next, a hole is made in the sealing sheet 15, and a pipe of a vacuum pump (not shown) is inserted into the hole to seal (see a dotted line). (8) In this state, while the thermosetting resin impregnated in the carbon sheet 12 is cured by heating with heating means to be described later, and the air in the sealing sheet 15 is sucked by a vacuum pump, the carbon sheet 12 Adhere and fix to the surface.
Thereafter, the sealing sheet 15 is removed, and the perforated release film 13 and the continuous pore porous cushioning member (nonwoven fabric) 14 are peeled off.

As described above, a perforated release film 13 having a large number of small holes is laminated on the carbon sheet 12,
By laminating the continuous pore porous buffer member 14 thereon, the air between the carbon sheet 12 and the surface of the concrete 11 and the carbon sheet 12 itself become small pores of the perforated release film 13 and the continuous pore porous buffer. Through the continuous pores in the member 14, suction is performed uniformly over the entire surface, and no voids are formed. That is, since the continuous pore porous buffer member (nonwoven fabric) 14 uniformly presses the perforated release film 13 over the entire surface by the vacuum suction operation, the air is uniformly sucked without the carbon sheet 12 being violent and waving. Is done. As a result, there is no concern that the air pool remains, and the air is appropriately sucked over the entire sealed area, and the concrete 11 and the carbon sheet 12 are uniformly adhered over the entire surface. In other words, the air at the part distant from the suction place is also sucked evenly.

FIGS. 2 and 3 are explanatory views of a first embodiment in which a carbon sheet is wound around a concrete pillar and fixed, and the same parts as those in FIG. 1 are denoted by the same reference numerals. 21 is a concrete column, 22 (FIG. 3) is a vacuum pump for vacuum suction in the sealing sheet, 23 is a pipe, and 24 is an electrode member for energizing the carbon sheet (hidden behind the column but another Exists), 25 is a power source such as a generator, and 26 is a lead wire connecting between the electrode and the power source. Electrode member 24
, 24a is an electrode, 24b is a suction cup, and 24c is a support plate. The suction cup 24b is pressed against the column 21 from above the sealing sheet 15, and is sucked by a vacuum pump (not shown).
The electrode member 24 can be fixed to the pillar by vacuum-suctioning the inside of b.

When attaching the carbon sheet, (1)
Perform ground treatment such as polishing / removal of degraded layer on concrete surface, repair of cracks, etc. (2) Then apply adhesive or epoxy primer 20 etc. on concrete surface, (3) dry primer and fill with epoxy putty etc. Make irregularity correction. (4) After correcting the unevenness, the carbon sheet 12 is wound around the surface of the pillar 21, and (5) a perforated release film 13 is laminated on the carbon sheet (see FIG. 2 (a)), and a continuous Porous porous cushioning members (nonwoven fabric) 14 are laminated, and these are covered with a sealing sheet 15 (see FIG. 2B).
(6) Then, the outer periphery of the sealing sheet 15 and the surface of the concrete 11 are sealed by the sealing 16 to make the inside of the sealing sheet airtight (see FIG. 3). (7) Thereafter, a hole is formed in the sealing sheet 15 and the pipe 23 of the vacuum pump 22 is formed in the hole.
Insert and seal. (8) In this state, the electrode member 24 is attached to the opposing two points of the column 21 from above the sealing sheet 15, and after attaching the electrode, a DC or AC voltage is applied to the electrode 24a. Carbon sheet 1 by applying voltage
2 is energized and generates heat.
The thermosetting resin impregnated in 2 is cured. If the air in the sealing sheet 15 is sucked by the vacuum pump 22 in parallel with the energization, the carbon sheet 12 hardens while being in close contact with the surface of the concrete 11, and adheres to the surface of the concrete. In the above, the case where the perforated release film and the nonwoven fabric are laminated on the carbon sheet on site has been described. However, these laminated products can be prepared in advance.

(B) Second Embodiment FIG. 4 is an explanatory view of a method for repairing or reinforcing a concrete structure according to a second embodiment of the present invention, and FIG. 4 (a) shows a method for repairing a concrete wall or a floor slab. FIG. 1 (b) shows an example of a flat construction in which a carbon sheet is attached, and FIG. 4, the same parts as those in the first embodiment of FIG. 1 are denoted by the same reference numerals. In the figure, 11 is concrete, 12 is a carbon fiber prepreg sheet (carbon sheet) impregnated with a thermosetting resin, 31 is an expanded porous polytetrafluoroethylene sheet (ePTFE sheet), and 15 is a seal for sealing these sheets. The sheet for sealing 16 is provided between the outer periphery of the sheet for sealing 15 and the surface of the concrete 11, and is a seam for keeping the space therebetween airtight. An adhesive or primer is appropriately applied to the concrete surface.

The ePTFE sheet 31 is a material excellent in weather resistance, ultraviolet shielding property, cold resistance, water resistance, and flexibility, and is described in, for example, Japanese Patent Publication No. 53-39719 and Japanese Patent Publication No. 51-18991. It is manufactured by a manufacturing method, and its microstructure is also known together with the manufacturing method. The ePTFE sheet 31 is formed by extruding a paste molded body composed of a mixture of fine powder of PTFE (polytetrafluoroethylene) and a lubricating aid such as petroleum naphtha through a die, and then heating the extruded material. After evaporating and removing the lubricating aid, it is manufactured by stretching uniaxially or biaxially at a high temperature not higher than the melting point of PTFE. Further, in order to fix a microstructure generated by stretching or to improve dimensional stability, it is necessary to keep the PT fixed in the stretched state.
In some cases, a baking treatment of heating to a temperature equal to or higher than the melting point of FE and then cooling is performed.

The ePTFE sheet manufactured as described above is an extremely flexible sheet having a pure white and marshmallow-like feel. Observation of this sheet with an electron microscope shows that both the surface and the inside are formed of fibrils (fibrils) and nodes (nodes) connecting them, and have a unique fibrous porous structure. ePT
In the FE sheet, spaces called "holes" defined by these fibrils and nodes exist inside the structure, and these spaces (voids) are continuous from the front surface to the back surface of the sheet, and thus have air permeability. Will be. The structure of the fibril / node structure changes depending on the stretching direction and the stretching ratio. For example, when stretched in a uniaxial direction, the fibrils become unidirectionally oriented interdigital, and the nodes connecting the fibrils are observed as islands which are elongated at right angles to the stretching direction. On the other hand, when biaxially stretched, fibrils spread radially, and the nodes connecting them are observed as fine particles rather than islands. In addition, when the stretching ratio is increased, the fibrils become longer, the node shape becomes relatively smaller, and ultimately a so-called nodeless structure consisting of only fibrils is obtained.

The ePTFE sheet is made of pure PTFE, and both the fibrils and the nodes characterizing the structure are PTFE. PTFE is a chemically extremely stable resin, and is well known as a material having excellent weather resistance, ultraviolet resistance, heat resistance, cold resistance, water resistance and the like. Thus, ePTFE is essentially PTFE itself, has its excellent chemical stability, is not oxidized by air, and is resistant to ultraviolet light. Also, PTFE is not synthesized in nature and is not eroded by bacteria. Further, since the ePTFE sheet has a porous structure, it can be bonded and fused by a so-called anchor effect.

When the carbon sheet is attached, (1) ground treatment such as polishing and removal of a deteriorated layer on the concrete surface and repair of cracks are performed. (2) Then, an adhesive or epoxy primer is applied to the concrete surface. Apply,
(3) After drying the primer, correct unevenness such as filling with epoxy putty. (4) Thereafter, the carbon sheet 12 is attached or wrapped around the concrete surface to be repaired and reinforced, and (5) the ePTFE sheet 31 is laminated on the carbon sheet, and (6) the sealing sheet 15 Covered with
The seam between the outer periphery of the sealing sheet 15 and the surface of the concrete slab 11 is sealed with the seam 16 to make the inside of the sealing sheet airtight. (7) Next, a hole is made in the sealing sheet 15, and a pipe of a vacuum pump (not shown) is inserted into the hole to seal (see a dotted line). (8) In such a state, while the thermosetting resin impregnated in the carbon sheet 12 is cured by heating with appropriate heating means, and the air in the sealing sheet 15 is sucked by a vacuum pump, the carbon sheet 12 Adhere and fix to the surface. Thereafter, the sealing sheet 15 is removed.

In the manner described above, the carbon sheet 12
Since heating and suction are performed in a state in which the ePTFE sheet 31 is stacked on the top, air is locally suctioned and does not remain.
The air in the entire area is sucked through the continuous pores of the PTFE sheet 31 without unevenness, so that the carbon sheet 12 and the surface of the concrete 11 adhere to each other. At the same time, the thermoplastic resin of the carbon sheet 12 is melted by heating and penetrates into the network structure of the ePTFE sheet 31, so that the carbon sheet 12 and the ePTFE sheet 31 are closely adhered and integrated. ePTFE
Develops excellent weather resistance as described above, and in particular prevents UV deterioration, thereby preventing the carbon sheet from deteriorating and thereby ensuring the strength of the reinforced concrete skeleton stably for many years. Since the ePTFE sheet 31 used for fixing the carbon sheet 12 remains on the concrete frame, it is not necessary to remove and remove the ePTFE sheet 31. In the above, the case where the ePTFE sheet is laminated on the carbon sheet on site has been described, but these laminated products can be prepared in advance. As described above, the present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0019]

As described above, according to the present invention, a perforated release film having a number of small holes is laminated on a carbon sheet, and a continuous porous porous cushioning member is laminated thereon. And sealing the film and buffer member with a sealing sheet, while curing the thermosetting resin by heating,
Since the air in the sealing sheet was sucked and the carbon sheet was attached to the surface of the concrete frame, the air between the carbon sheet and the concrete surface and the carbon sheet itself became small holes and continuous pores in the perforated release film. The entire surface is uniformly sucked through the continuous pores in the porous cushioning member, and voids are eliminated, so that the reinforcing and repairing effect by the carbon sheet can be maintained.

According to the present invention, an expanded porous polytetrafluoroethylene sheet (ePTF) is formed on a carbon sheet.
E sheets) are laminated, these sheets are sealed with a sealing sheet, and while the thermosetting resin is cured by heating, air in the sealing sheet is sucked to attach the carbon sheet to the concrete frame. From ePT
The air in the entire area inside the seal is sucked through the continuous pores of the FE sheet evenly, so that the carbon sheet can be in close contact with the concrete surface, and the thermosetting resin of the carbon sheet is melted by heating and the mesh of the ePTFE sheet Since the carbon sheet and the ePTFE sheet can penetrate into the structure and adhere and integrate with each other, the carbon sheet can be prevented from being deteriorated by ultraviolet rays.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory view (part 1) of a case where a carbon sheet is wound around a pillar and fixed.

FIG. 3 is an explanatory view (part 2) of a case where a carbon sheet is wound around a pillar and fixed.

FIG. 4 is an explanatory diagram of a second embodiment of the present invention.

FIG. 5 is an explanatory diagram when a carbon sheet is attached for reinforcing a building structure.

FIG. 6 is an explanatory diagram when a carbon sheet is attached for reinforcing a lining portion of a tunnel.

FIG. 7 is an explanatory diagram when a carbon sheet is attached for reinforcing a bridge.

FIG. 8 is an explanatory view of a conventional carbon sheet mounting method by vacuum suction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Concrete 12 Carbon fiber prepreg sheet (carbon sheet) 13 Perforated release film 14 Continuous porous porous cushioning member (nonwoven fabric) 15 Sealing sheet 16 Sealing

Claims (2)

[Claims] 1. A method for repairing or reinforcing a concrete structure by attaching a carbon fiber prepreg sheet impregnated with a thermosetting resin to a concrete structure while heating the carbon fiber prepreg sheet. Are laminated, a continuous porous porous buffer member is laminated thereon, these sheets, the film and the buffer member are sealed with a sealing sheet, and the thermosetting resin is heated. A method for repairing or reinforcing a concrete structure, characterized in that air in a sealing sheet is sucked while being cured by the method, and a carbon fiber prepreg sheet is attached to a surface of a concrete body. 2. A method for repairing or reinforcing a concrete structure by attaching a carbon fiber prepreg sheet impregnated with a thermosetting resin to a concrete structure while heating the stretched porous poly prepreg sheet on the carbon fiber prepreg sheet. Tetrafluoroethylene sheets are laminated, these sheets are sealed with a sealing sheet, and while the thermosetting resin is cured by heating, the air in the sealing sheet is sucked, and the carbon fiber prepreg sheet is attached to the concrete body. A method for repairing or reinforcing a concrete structure.