JP5629501B2 - Method for repairing concrete structure and concrete structure - Google Patents

Description

  The present invention relates to a method for repairing a concrete structure in which a fiber sheet is bonded to the surface of the concrete structure, and a concrete structure repaired by the repair method.

  In general, a concrete structure is cracked in concrete due to various factors such as aging of itself, earthquake, and land subsidence, and when the cracks are combined, there is a risk of dropping at the location. Therefore, when changes such as cracks occur in the concrete structure, it is necessary to perform appropriate repairs and reinforcements in consideration of the type and degree of the change.

  Conventionally, as a repair method for a deteriorated concrete structure, a fiber sheet obtained by molding a reinforcing fiber such as carbon fiber, glass fiber, or aramid fiber into a sheet shape or a woven shape, and a concrete structure with a room temperature curable resin such as an epoxy resin A method of adhering to an object surface is performed (see Patent Documents 1 to 4).

Patent Document 1 discloses a method for repairing a concrete structure in which a fiber sheet in which a carbon fiber reinforcing layer and a fiber adhesion auxiliary layer are integrated is bonded to a concrete surface with a room temperature curing resin.
However, this concrete structure repair method uses carbon fiber as a fiber sheet. Since carbon fiber is black and opaque, the state of the concrete surface cannot be observed after bonding the fiber sheet. For this reason, there are problems such as the possibility of causing a short-circuit accident when constructing in an electrified railway tunnel.

Patent Document 2 discloses a fiber sheet bonding method in which an FRP sheet in which a fiber sheet and a flexible resin are integrated is bonded to a concrete surface with a putty-like resin.
However, since this fiber sheet bonding method uses an FRP sheet in which the periphery of the reinforcing fiber is integrated with a base resin, the work of attaching without entraining air between the concrete and the concrete is complicated, and the fiber sheet And the base resin are integrated, there is a problem that the mass is large, workability when installing on the ceiling surface, etc., or the FRP sheet once attached may be peeled off. .

Patent Document 3 discloses a repair method for a concrete structure using a fiber sheet and an anchor in combination with an adhesive.
However, this repair method for concrete structures is to use a step drill that is not generally used as a means for drilling holes in concrete for anchor installation. The work of tightening the square flange portion with a ratchet is necessary, and the work is complicated and takes time.

Patent Document 4 discloses a method for repairing a concrete structure in which a primer is applied to the surface of the concrete structure, and an aramid fiber sheet is adhered using an acrylic adhesive.
However, Patent Document 4 does not describe the use of a primer or adhesive having a specific viscosity.

JP 2004-043322 A JP 2009-162033 A Japanese Patent No. 4113922 JP 2001-355343 A

  The purpose of the present invention is that the workability of construction is good, the progress of deterioration such as cracks existing on the surface of the concrete structure can be confirmed visually after repair, and a method for repairing a concrete structure excellent in durability and The concrete structure is to be provided.

The present invention employs the following means in order to solve the above problems.
(1) A method for repairing a concrete structure in which a fiber sheet is adhered to a surface of a concrete structure with a two-component main component type acrylic resin adhesive mainly composed of (meth) acrylic acid ester composed of a primer and a fiber adhesive. The primer has a viscosity of 200 to 2,000 mPa · s at 20 ° C. and 20 rpm measured according to JIS K 7117-1, and the fiber sheet is formed of two or three strands of bundles of a plurality of filaments. JIS K 7117 immediately after mixing of the two liquids of the fiber adhesive, in a mesh shape arranged in the direction, and the shape of the mesh surrounded by a plurality of strands is a square or a triangle having a side of 7 to 16 mm. -1 measured according to -1, viscosity at 20rpm, 20rpm 2,500 ~ 5,0
This is a repair method for a concrete structure having a viscosity of 15,000 to 30,000 mPa · s at 20 ° C. and 20 rpm measured according to JIS K 7117-1 when it is allowed to stand for 5 minutes after mixing at 00 mPa · s.
(2) The primer is applied to the surface of the concrete structure, then the fiber adhesive is applied, the fiber sheet is applied, the fiber adhesive is further applied, and the fiber sheet is applied to the concrete structure. It is a repair method of the concrete structure of said (1) adhere | attached on the surface.
(3) The filaments constituting the fiber sheet are the aramid fibers (1) or (
This is a repair method for concrete structures in 2).
(4) The method for repairing a concrete structure according to any one of (1) to (3), wherein the primer and the fiber adhesive are transparent or translucent.
(5) The method for repairing a concrete structure according to any one of (1) to (4), wherein an application amount of the primer is 0.05 to 0.5 kg / m ² .
(6) The method for repairing a concrete structure according to any one of (1) to (5), wherein an application amount of the fiber adhesive is 0.4 to 1.1 kg / m ² .
(7) A holding fixture consisting of a stainless steel plate and a bottom-up anchor body is installed in the hole provided in the concrete structure, and JIS K is installed in the gap between the bottom-bottom anchor body and the hole wall of the concrete structure.
Filled and fixed with an acrylic resin filler that has a viscosity of 50,000 to 150,000 mPa · s at 20 ° C and 20 rpm measured according to 7117-1, and a tensile shear bond strength with stainless steel of 5 N / mm ² or more. ,
(1) to (6) for fixing the fiber sheet bonded with the primer and the fiber adhesive.
The method for repairing a concrete structure according to any one of items 1).
(8) The method for repairing a concrete structure according to (7), wherein the dish of the holding device is covered with the acrylic resin filler or the fiber adhesive, and the dish surface is shielded from the atmosphere.
(9) The tensile shear bond strength of the fiber adhesive with stainless steel is 5 N / mm ² or more (
This is a method for repairing a concrete structure according to 8).
(10) A concrete structure repaired by the concrete structure repair method according to any one of (1) to (9).

  According to the present invention, the progress of deterioration such as cracks existing on the surface of the concrete structure can be visually observed even after the fiber sheet is bonded to the concrete structure, the workability during construction is also good, and the fiber sheet The fiber sheet can be more stably held on the concrete structure surface by installing and fixing the adhesive sheet with the adhesive, or the adhesive and the holding tool, and further coating the tray of the holding tool with the acrylic resin filler or the fiber adhesive. In addition, long-term reliable repair is possible.

It is a typical shape figure which shows one embodiment of the fiber sheet used for the repair method of the concrete structure of this invention. It is a figure which shows the other embodiment of the fiber sheet used for the repair method of the concrete structure of this invention. It is a typical shape figure which shows the whole structure of the repair method of the concrete structure of this invention. It is a schematic block diagram for demonstrating the visual observation test method for investigating the effect of the repair method of the concrete structure of this invention. It is a schematic block diagram for demonstrating the test method for investigating the effect of the acrylic resin filler of the repair method of the concrete structure of this invention. It is a schematic block diagram for demonstrating the test method for investigating the durability of the repair method of the concrete structure of this invention.

  Hereinafter, although the repair method of the concrete structure which concerns on this invention, and its concrete structure are demonstrated in detail using drawing, this invention is not limited to these drawings.

The fiber sheet used in the present invention has a mesh shape in which strands in which a plurality of filaments are bundled are arranged in two or three directions.
FIG. 1 is a typical shape view showing one embodiment of a fiber sheet used in the concrete structure of the present invention.
In FIG. 1, a fiber sheet 1 is formed by arranging strands 2 in which a plurality of filaments are bundled in two directions into a sheet shape, and a square mesh of sides a and b is formed by the arranged strands 2. Here, the square side a or b is 7 to 16 mm.

FIG. 2 is a shape diagram showing another embodiment of the fiber sheet used in the present invention.
The fiber sheet 1 of FIG. 2 has strands 2 arranged in three directions, and a triangular mesh having sides c, d, and e is formed by the arranged strands. Here, the sides c, d, and e of the triangle are 7 to 16 mm.

  By using the fiber sheet having the shape shown in FIG. 1 or FIG. 2, the progress of deterioration such as cracks and cracks on the surface of the concrete structure is visually observed by the mesh of the fiber sheet even after the fiber sheet is bonded to the surface of the concrete structure. Although it is possible to observe, if one side of the square or triangular mesh shape is less than 2 mm, for example, it becomes difficult to observe a 0.2 mm crack on the surface of the concrete structure. If one side exceeds 20mm, the stiffness of the fiber sheet is reduced, the contact area between the fiber sheet and the surface of the actual concrete structure is reduced, and the fiber sheet is peeled off due to its own weight during the fiber sheet attaching operation. The workability may be reduced.

  The material of the fiber sheet may be any material having a reinforcing effect, such as aramid fiber, carbon fiber, glass fiber, polyethylene fiber, vinylon fiber, and nylon fiber. Two or more types of materials can be selected. In particular, when considering use in an electrified railway tunnel, it is preferable to use aramid fibers in consideration of the non-conductive property and the reinforcing effect of the fiber sheet itself.

  The adhesive used in the present invention includes a liquid containing one or more kinds of (meth) acrylic acid esters and organic peroxides, and a reduction that decomposes one or more kinds of (meth) acrylic acid esters and organic peroxides. It is a two-component main component type acrylic resin adhesive made of (meth) acrylic acid ester as a main raw material, and is composed of a primer and a fiber adhesive. These adhesives are preferably transparent or translucent to enable observation of deformation on the surface of the concrete structure after construction. By using such a transparent adhesive, the fiber sheet is bonded to the surface of the concrete structure and reinforced (repaired). Progress can be directly observed visually.

  The two-component main component acrylic resin adhesive that uses (meth) acrylic acid ester as the main raw material is less likely to cause poor curing even when the mixing ratio of the two components is slightly shifted, and the properties of the adhesive after curing. It is useful for ensuring the quality at the site of repairing concrete structures such as outdoors.

The primer is used to enhance the adhesion between the concrete structure and the fiber adhesive, and is applied to the surface of the concrete structure to be impregnated and cured in the concrete structure. And, for the purpose of improving the adhesion with the fiber adhesive applied after the primer application by forming a cured primer layer on the concrete structure surface, the viscosity of the primer is preferably lower viscosity From the viewpoint of preventing contamination of the surroundings caused by dripping of the primer as much as possible during construction on a vertical surface or ceiling surface of a concrete structure, in the present invention, a viscosity of 20 ° C. and 20 rpm measured according to JIS K7117-1 Is 200 to 2,000 mPa · s. If the viscosity is less than 200 mPa · s, dripping may become severe, or most of the material may permeate into the concrete structure and a primer layer may not be formed on the surface of the concrete structure. On the other hand, if the viscosity is higher than 2,000 mPa · s, the impregnation property into the concrete structure is lowered, and there is a possibility that long-term adhesion durability cannot be obtained.
The coating amount of the primer, the degree of impregnation curing primer, long-term adhesion durability, and from the viewpoint of workability and the like, preferably ^{0.05~0.5kg / m 2, 0.1~0.3kg / m} 2 is more preferable.

The fiber adhesive is an adhesive for applying on the cured primer layer and sticking the fiber sheet. When mixing two liquids, it is preferable to have a low viscosity at the time of application. Since the pasted fiber sheet may peel off due to its own weight or natural wind, the present invention has a viscosity of 20 ° C. and 20 rpm measured according to JIS K 7117-1 immediately after mixing the two liquids. Is 2,500 to 5,000 mPa · s.
Immediately after mixing means that two liquids are weighed and stirred for 1 minute with an electric mixer. If the viscosity immediately after mixing is less than 2,500 mPa · s, the thickness that can be applied cannot be secured, which may make it difficult to apply the fiber sheet. If the viscosity is higher than 5,000 mPa · s, the mixing property and application workability deteriorate. There is a fear.

In the present invention, the fiber sheet bonding is usually performed after about 5 minutes from the application of the fiber adhesive by, for example, roller coating.
In order to improve the fiber sheet retention on the surface of the concrete structure after the fiber sheet is pasted, the fiber adhesive is in accordance with JIS K 7117-1 in the present invention when two liquids are mixed and then allowed to stand for 5 minutes. The viscosity at 20 ° C. and 20 rpm is 15,000 to 30,000 mPa · s. When the viscosity is less than 15,000 mPa · s, the attached fiber sheet is easily peeled off by natural wind, and when the viscosity is higher than 30,000 mPa · s, the fiber adhesive is less likely to blend into the fiber, making the fiber sheet affixing work complicated. There is a risk of becoming.

The application amount of the fiber adhesive used in the present invention is an amount that does not deviate from the purpose of allowing the surface state of the concrete structure to be visually observed even after the fiber sheet is bonded, and the long-term adhesion durability and fiber sheet pasting From the viewpoint of the visibility of the underlying concrete, 0.4 to 1.1 kg / m ² is preferable, and 0.5 to 0.8 kg / m ² is more preferable.

FIG. 3 is a typical shape diagram showing the overall structure of the concrete structure repairing method of the present invention, in which a holding device composed of a plate made of stainless steel and an expanded bottom anchor body is used for the present invention. It is a typical drawing which shows an embodiment.
The expanded bottom anchor main body 4 is provided with an annular groove on the surface of a hollow structure main body, a slit from the tip, and a driving pin inserted into the hollow portion.
The plate 5 is provided with a through hole at the bottom of a cup member having a recess formed at the center, and a flange member is formed at the peripheral edge of the cup member.
The construction method of the holding device is not particularly limited. First, the concrete is drilled about 10 mm longer than the length of the bottomed anchor body 4 and the hole diameter is about 0.6 mm wider than the diameter of the bottomed anchor body 4. Then, the shavings in the hole are removed and cleaned, the acrylic resin filler 6 is filled into the hole, and then the holding device 3 in which the bottomed anchor body 4 is inserted into the through hole of the dish 5 is inserted into the hole, and the driving pin The bottom of the expanded anchor main body 4 is expanded by hitting with a hammer and fixed. Since the excess acrylic resin filler 6 protrudes from the inside of the hole after the construction, the dish is covered with the acrylic resin filler 6 protruding using a rubber spatula or the like. If the acrylic resin filler is insufficient, the dish can be covered with a fiber adhesive.
As shown in FIG. 3, the holding device 3 passes through the fiber sheet 9 attached with an adhesive composed of a primer and a fiber adhesive, and is installed and fixed in a hole of the concrete structure 8 provided in advance. The dish 5 has a function of pressing the fiber sheet 9 attached with a primer and a fiber adhesive against the surface of the concrete structure.

  As shown in FIG. 3, in the present invention, the acrylic resin filler 6 is preferably filled in a gap between the expanded bottom anchor body 4 and the wall of the hole drilled in the concrete structure 8. If the acrylic resin filler 6 is not present, the pull-out load of the anchor body 4 may be low, or the pull-out load may decrease due to long-term vibration.

  Acrylic resin fillers need to be held in the holes of the concrete structure sufficiently when installed on vertical surfaces or ceiling surfaces. Measured according to JIS K 7117-1 from the aspect of load reduction, reduction of pull-out load due to long-term vibration, aspect of filling with acrylic resin filler, and aspect of insertion into anchor holes. The viscosity at 20 ° C. and 20 rpm is preferably 50,000 to 150,000 mPa · s.

  Further, as shown in FIG. 3, covering the plate 5 of the holding device 3 with the acrylic resin filler (7) means that the entire holding device is further bonded to the concrete structure 8 and an adhesive. 9 is preferable in order to integrate. It is also possible to cover the dish 5 of the holding device 3 with a fiber adhesive instead of the acrylic resin filler (7).

For this reason, the tensile shear bond strength according to JIS K 6850 of acrylic resin fillers and fiber adhesives with stainless steel, which is the material of the plate that constitutes the holding device, is the reason for the destruction of the coating due to long-term vibration, the concrete of the holding device It is preferable that it is 5 N / mm ² or more from the viewpoint of deterioration of integration with the structure or the fiber sheet and the durability.

  The present invention is basically the same as a procedure for adhesion reinforcement (repair) of a fiber sheet of a concrete structure at a repair site of a concrete structure. That is, as a procedure, it can carry out in order of the kelen process of a concrete structure surface, primer application, and fiber sheet sticking using a fiber adhesive. Installation and fixing of the holding device may be performed either before or after the fiber adhesive is cured after the fiber sheet is attached.

  The number of fiber sheets affixed to the concrete structure is appropriately selected depending on the degree of repair and reinforcement required, but visual observation of the surface of the concrete structure after construction, which is the object of the present invention, is possible. A range, for example, 2 or less is preferable.

  Next, details of tests conducted for the purpose of confirming the effects of the present invention will be described by way of examples.

Experimental example 1
Table 1 shows the test results of examining the viscosity suitability of a primer which is one of adhesives.
The surface of the type N300 of the pavement flat plate in the precast unreinforced concrete product specified in JIS A 5371 was sandblasted to obtain a test body, and the viscosity suitability of the primer was examined.
A primer having the viscosity shown in Table 1 in which 0.1% by mass of a fluorescent dye was dissolved in an atmosphere of 20 ° C. and 60% relative humidity was applied to the vertical surface of the test specimen at 0.2 kg / m ² , and left for 7 days. The viscosity of the primer was examined. Evaluation was made by observing the construction situation of the vertical surface, the state of the surface after 7 days, and the state of the cross section, and evaluating the expected primer effect based on them. The results are also shown in Table 1.
For comparison, a comparative primer having a viscosity of 100 mPa · s was prepared and used.

<Materials used>
Primer: Two-component main component acrylic resin adhesive, viscosity adjusted to 250 mPa · s, added with aerosil, transparent or translucent comparative primer: two-component main component acrylic resin adhesive, prototype, Viscosity 100mPa ・ s, transparent

<Evaluation method>
Viscosity: According to JIS K 7117-1, the installation situation of the vertical surface measured at 20 ° C and 20rpm:
Visually, 50% or more of the amount of primer applied is not allowed to sag, 30% to less than 50% is allowed to sag, 10% to 30% is less than 30% The case was good, and the case where less than 10% by mass dropped was considered excellent.
Surface condition after 7 days:
Visually, the primer is not completely impregnated on the surface, the primer is hardened on the surface, and the area is 35% or more and less than 50% of the total surface area. A primer cured layer is formed, and the area is 50% or more and less than 75% of the entire surface area. The primer cured layer is formed on the surface, and the area is 75% of the entire surface area. % Was superior.
Sectional state:
The test specimen was cut with a diamond cutter, an ultraviolet lamp was irradiated onto the coated cross section of the material, and the impregnated and cured state was visually observed. The coated primer does not remain near the coated surface, but almost completely diffuses inside the specimen, and when the fluorescent coloration by the ultraviolet lamp is not observed or the coated primer remains near the coated surface, it is about 0.1 mm. Impregnation is not possible, impregnation is not possible, applied primer remains in the vicinity of the application surface, and impregnation of less than 0.1 mm is partially recognized.Applied primer remains in the vicinity of the application surface. The case where impregnation of not less than 0.5 mm and less than 0.5 mm was recognized was good, and the case where the coated primer remained in the vicinity of the coated surface and impregnation of 0.5 to 1 mm was recognized.
Expected primer effects:
In the case of evaluation of 3 items, the construction status of the vertical surface, the surface condition after 7 days, and the state of the cross section, it is not possible if even one item is impossible. The case where there is no impossibility in the evaluation of three items and the case where there is one item is good.

  From Table 1, it was found that the primer viscosity is preferably 200 to 2,000 mPa · s.

Experimental example 2
Table 2 shows the results of examining the viscosity suitability of a fiber adhesive that is one of the adhesives.
Using a commercially available box culvert internal ceiling surface, the surface of 105 cm × 105 cm was blasted, primer α was applied at 0.2 kg / m ² , and fiber sheet A was coated with 0.6 kg / m ² (fiber sheet before pasting 0.4kg / m ^2, fiber sheet pasted after 0.2kg / m ²⁾ was stuck in. The ease of manual mixing of materials (mixability of materials), the state of fiber sheet pasting work, and the effect of forced air (anti-wind pressure) were observed, and the overall results were evaluated. The results are also shown in Table 2.

<Materials used>
Fiber sheet A: Aramid fiber, fiber amount 90g / m ² , mesh shape is square, each side of square is 7-8mm, 100cm × 100cm
Primer α: Acrylic resin adhesive, viscosity 250 mPa · s, transparent fiber adhesive: Acrylic resin adhesive, viscosity adjusted by adding Aerosil, transparent or translucent

<Evaluation method>
Mixability of materials:
Two solutions of the fiber adhesive were weighed in a cylindrical plastic container having a diameter of 14 cm and a capacity of 2 liters, each 500 g, and stirred with a glass rod having a diameter of 7 mm to evaluate the ease of stirring and mixing. By visual observation, the time when it is recognized that the overall hue is almost uniform by mixing with stirring is not possible if it is longer than 60 seconds, over 45 seconds, within 60 seconds, over 30 seconds, within 45 seconds The case was good and the case within 30 seconds was excellent.
Fiber sheet pasting work status:
Since the viscosity of the fiber adhesive is dripping drastically and the application of 0.4 kg / m ² cannot be secured, or when the fiber sheet attached is too sticky to the concrete surface, Although the applied fiber adhesive sagged down, the case where the fiber sheet was in close contact was acceptable, the case where the applied fiber adhesive did not sag and the fiber sheet was in close contact was considered good.
Wind pressure resistance:
Check that there is no problem in construction by sending forced air at 5m / s with a blower into the box culvert. If the fiber sheet peels off from the end and falls entirely, it is impossible to peel off. The case where it was recognized but the whole was retained was acceptable, and the case where no peeling was observed was considered good.
Overall results:
In the result of the evaluation item, the case where one or more is impossible is not possible, the case is not impossible, the case where two or more are possible is acceptable, the case where there is no impossible and one is acceptable is good, and the previous item is impossible or possible The case where there was no is excellent.

  From Table 2, the viscosity of the fiber adhesive is from 2,500 to 5,000 mPa · s after mixing the two liquids from the viewpoints of the mixing properties of the two liquids, fiber sheet sticking workability, and wind pressure resistance. It can be seen that a viscosity of 15,000 to 30,000 mPa · s when standing for 5 minutes is suitable.

Experimental example 3
FIG. 4 is a schematic configuration diagram for explaining a surface visual observation test method after a concrete structure repair method according to the present invention. 4A is a side view and FIG. 4B is a plan view.
A commercially available 10 cm x 10 cm x 40 cm concrete product is cut into two 10 cm x 10 cm x 20 cm with a diamond cutter, the cut surfaces are butted, and a steel wire 11 with a diameter of 0.2 mm is used as a spacer, and an acrylic resin is made in this gap. The concrete structure crack injection material 12 was injected, cured, and joined to prepare a concrete structure test specimen.
One surface of this concrete structure test body was sandblasted, and 0.2 kg / m ^{2 of} primer α (primer 13) was applied and cured.
Next, 0.4 kg / m ^{2 of} fiber adhesive a (fiber adhesive 14) was applied, the fiber sheet 15 shown in Table 3 was applied, and then 0.2 kg / m ^{2 of} fiber adhesive a was applied for repair. A concrete structure specimen was obtained.
A load test was conducted to generate new cracks on the surface of the repaired concrete structure specimen. The load test is performed by a three-part load bending test method (based on JIS A 1106) using a universal testing machine (Autograph AG-300KNG, manufactured by Shimadzu Corporation), and unloaded when the maximum load is observed. Observations were made. We also observed the condition of a 0.2 mm gap provided as a simulated crack. The results are also shown in Table 3.

<Materials used>
Fiber sheet B: Aramid fiber, fiber amount 180g / m ² , mesh shape is square, and each side of the square is 2-3mm
Fiber sheet E: aramid fiber, fiber amount 325 g / m ² , gap between strands 1 mm or less Fiber adhesive a: acrylic resin adhesive, viscosity 4,000 mPa · s immediately after mixing, viscosity 21,000 when left for 5 minutes after mixing mPa · s, transparent

<Evaluation method>
Pre-observation situation of 0.2 mm gap:
The case where it was impossible to observe the situation of a 0.2 mm gap provided in advance as a simulated crack was impossible, and the case where visual observation was possible was considered good.
Observation status of new cracks that occurred during loading:
The case where the observation is impossible is not possible, the case where the crack can be found visually is good, and the case where the crack can be easily found visually is excellent.

  As shown in Table 3, if one side of the mesh shape formed by the strands is 2 mm or more, a 0.2 mm gap or a newly generated 0.2 mm crack on the surface of the concrete structure specimen was observed. I was able to confirm that I could find it.

Experimental Example 4
Table 4 shows the test results showing the effect that one side of the mesh shape formed by the strands of the fiber sheet of the present invention is 20 mm or less.
Using the internal ceiling surface of a commercially available box culvert, the surface of 105cm × 105cm is blasted, primer α is applied 0.2kg / m ² , and the fiber sheet shown in Table 4 is pasted with fiber adhesive a0.4kg / m ² It was performed in the same manner as in Experimental Example 3 except that the workability of the ceiling surface was evaluated. The results are also shown in Table 4.

<Materials used>
Fiber sheet C: Aramid fiber, fiber sheet α having a fiber amount of 90 g / m ² , with one strand removed in the weft direction, mesh shape is square and each side is 14 to 16 mm
Fiber sheet D: Aramid fiber, fiber sheet α having a fiber amount of 90 g / m ² , ^two strands in the weft direction removed, mesh shape is quadrangular and each side is 21-24 mm

<Evaluation method>
Wind pressure resistance:
A forced air with a wind speed of 5 m / s was sent into the box culvert with a blower, and it was confirmed that there were no construction problems. Evaluation is the status of fiber sheet affixing work, confirmation of the effect of forced air, the rigidity of the fiber sheet is low, the affixing work is difficult, the contact area with the concrete surface is small, and the fiber sheet peels off due to the forced air The case where it happened was impossible, and the case where the pasting work was easy was judged as good.

  As shown in Table 4, one side of the mesh shape formed by the strands of the fiber sheet is preferably 20 mm or less from the viewpoint of wind resistance.

Experimental Example 5
The primer α in the amount shown in Table 5 is applied and cured, then the fiber adhesive a is applied at 0.4 kg / m ² , the fiber sheet A is applied, and the fiber adhesive a is further applied at 0.2 kg / m ^2. It applied similarly to Experimental example 3 except having obtained the concrete structure which apply | coated and repaired and evaluated the construction condition of a vertical surface, the state of a cross section, and comprehensive evaluation based on them. The results are also shown in Table 5.

<Evaluation method>
Comprehensive evaluation:
In the evaluation results of the two items of the construction status of the vertical surface and the state of the cross section, if there is an impossibility, it is not possible, there is no impossibility, if there is a possibility, yes, if there is no good or no good, one is good, good Two cases were excellent.

From Table 5, it was found that the primer coating amount is suitably 0.05 to 0.5 kg / m ² .

Experimental Example 6
The primer α is applied and cured at 0.2 kg / m ² , then the fiber adhesive a in the amount shown in Table 6 is applied, the fiber sheet A is applied, and the fiber adhesive a is further applied at 0.2 kg / m ^2. Similar to Experimental Example 3 except that the applied concrete structure was repaired and the fiber adhesive state applied before the fiber sheet was affixed, the fiber sheet affixing situation, and the overall evaluation based on them were evaluated. went. The results are also shown in Table 6.

<Evaluation method>
The state of the fiber adhesive applied before attaching the fiber sheet:
Since there are few fiber adhesives, it is impossible to apply fiber adhesives to the entire fiber sheet attachment range, or because there are many fiber adhesives, dripping is not noticeable. When the agent can be applied to the entire fiber sheet attachment range, or because there are many fiber adhesives, dripping can be observed. The fiber adhesive can be easily applied to the entire fiber sheet attachment range. A case where no sagging was observed was considered good.
Fiber sheet sticking situation:
Because there are few fiber adhesives, there is no place where the fiber sheet is lifted from the sticking surface, there is no place where the fiber sheet is lifted from the sticking surface, but the fiber adhesive partially to the strand of the fiber sheet The case where a portion where the impregnation of the fiber sheet was insufficient was observed, the case where there was no portion where the fiber sheet was lifted from the attachment surface, and the fiber adhesive was sufficiently impregnated into the strand of the fiber sheet was determined as good.
Comprehensive evaluation:
When the two-item evaluation of the state of the fiber adhesive applied before the fiber sheet is pasted and the state of sticking of the fiber sheet is not possible, it is not possible. When both the two items are acceptable, one item is acceptable and one item is acceptable. The case where is good is good, and the case where both items are good is considered excellent.

From Table 6, it was found that the application amount of the fiber adhesive is preferably 0.4 to 1.2 kg / m ^{2 in} total before and after the fiber sheet is attached.

Experimental Example 7
FIG. 5 is a conceptual diagram of a test body when the effect of the holding fixture installation and fixing method of the present invention is tested. The adhesive strength between the holding device and the acrylic resin filler was examined.
Only the anchor main body 4 of the holding device 3 was inserted and fixed in a hole drilled in advance on the ceiling of a commercially available box culvert.
As shown in Table 7, the acrylic resin filler was filled and the tensile test was done. The results are also shown in Table 7.

<Materials used>
Acrylic resin filler A: Viscosity 250mPa · s, JIS K 6850 tensile shear adhesive strength 20N / mm ² with stainless steel
Acrylic resin filler B: Viscosity 50,000 mPa · s, tensile shear bond strength with stainless steel according to JIS K 6850 12 N / mm ²
Acrylic resin filler C: viscosity 100,000mPa · s, JIS K 6850 tensile shear bond strength with stainless steel 12N / mm ²
Acrylic resin filler D: Viscosity 150,000mPa · s, tensile shear bond strength with stainless steel according to JIS K 6850 7N / mm ²

<Test and evaluation method>
Tensile test:
The anchor body was installed and fixed, and after 24 hours, an adapter for a tensile test was installed, and the maximum load was measured with a hydraulic center hole jack.
Rating:
The viscosity of the acrylic resin filler is low, and it cannot be filled when the ceiling surface is constructed or the anchor body is removed. The acrylic resin filler does not sag when the ceiling surface is constructed, and the anchor body may break. It was.

  As shown in Table 7, highly reliable fixing is possible by using an acrylic resin filler for installation and fixing of the holding device to the concrete.

Experimental Example 8
FIG. 6 is a schematic diagram of the test when the method for repairing a concrete structure of the present invention is applied to an actual concrete structure and durability is evaluated.
The repaired concrete structure is the side wall concrete of the horizontal shaft isolated from the main tunnel of the Shinkansen tunnel. This place is isolated from the main battle, but it receives a shock wind when passing through the Shinkansen.
Sidewall concrete 10 is blasted, primer α (primer 13) is applied at 0.2 kg / m ² , fiber adhesive a (fiber adhesive 14) is then applied at 0.4 kg / m ² , and fiber sheet A ( 110 cm × 110 cm of the fiber sheet 15) was pasted, and the fiber adhesive a was applied again at 0.2 kg / m ² to finish the whole.
Thereafter, a hole for installing and fixing the holding device 3 was drilled in the concrete, an acrylic resin filler 6 (not shown in FIG. 6) was filled in the hole, and the holding device 3 was installed and fixed.
The holding device was installed and fixed at a pitch of 50 cm inside 5 cm from the end of the fiber sheet. Furthermore, the plate 5 (not shown in FIG. 6) constituting the holding device 3 was covered with an acrylic resin filler 6 (not shown in FIG. 6) (the covered state is 7).
In addition, in order to confirm the effect of a holding | maintenance apparatus, the application | coating of an adhesive was not dared to the edge part 5cm of 4 sides of a fiber sheet.
Visual confirmation of the foundation and other appearance observations were made after 8 years had passed since the preparation of the test specimen. The results are shown in Table 8.
Moreover, the result of having similarly covered the dish 5 with the fiber adhesive b instead of the acrylic resin filler 6 is also described.

<Materials used>
Fiber adhesive b: Acrylic resin adhesive, viscosity 4,000 mPa · s immediately after mixing, viscosity 21,000 mPa · s when left for 5 minutes after mixing, tensile shear bond strength with stainless steel 17 N / mm ²

<Measurement and evaluation method>
Evaluation: The case where the holding device was pulled out, the case where the tray of the holding device was no longer pressing the fiber sheet was impossible, and the case where the configuration of the cross-sectional view of FIG.

As described above, by applying the method for repairing a concrete structure of the present invention, the surface state of the concrete structure can be visually observed even after the fiber sheet is bonded, and the concrete structure after the fiber sheet is bonded. The progress of deterioration of the surface of the object can be visually confirmed.
Therefore, it is possible to take measures at an early stage before occurrence of an abnormal phenomenon such as peeling or collapse of the concrete structure after the fiber sheet is bonded. In addition, the fiber sheet can be stably held on the surface of the concrete structure due to the synergistic effect of the adhesive and the holding device over a long period of time.

DESCRIPTION OF SYMBOLS 1 Fiber sheet 2 Strand in which a plurality of filaments are bundled 3 Holding device 4 Anchor body (in a state where the bottom is expanded)
5 Dish 6 Acrylic resin filler 7 Cover of dish (Acrylic resin filler or fiber adhesive)
8 Concrete structure 9 Fiber sheet 10a bonded with adhesive (primer and fiber adhesive) Concrete specimen 10b Concrete specimen 11 Steel wire 12 Crack injection material 13 Primer 14 Fiber adhesive 15 Fiber sheet 16 Tensile test jig (All the screws are hollowed out and cylindrical.)
a Mesh shape edges
b Mesh shape edges
c Mesh shape edges
d Mesh shape edges
e Mesh shape edges

Claims (10)

A method for repairing a concrete structure in which a fiber sheet is bonded to a surface of a concrete structure with a two-component main component type acrylic resin adhesive mainly composed of (meth) acrylic acid ester composed of a primer and a fiber adhesive, The primer has a viscosity of 200 to 2,000 mPa · s measured at 20 ° C. and 20 rpm measured according to JIS K 7117-1, and the fiber sheet is arranged in two or three directions in which strands are bundled with a plurality of filaments. The shape of the mesh surrounded by a plurality of strands is a square or a triangle having a side of 7 to 16 mm, and JIS K 7117-1 immediately after mixing the two liquids of the fiber adhesive. Measured according to JIS K 7117-1 when the viscosity at 20 ° C. and 20 rpm is 2,500 to 5,000 mPa · s after standing for 5 minutes after mixing, and the viscosity at 20 ° C. and 20 rpm is 15,000 to 30,000 mPa · s. Concrete structure characterized by being s The method of repair.   The primer is applied to the surface of the concrete structure, then the fiber adhesive is applied, the fiber sheet is attached, the fiber adhesive is further applied, and the fiber sheet is adhered to the surface of the concrete structure. The method for repairing a concrete structure according to claim 1, wherein:    The method for repairing a concrete structure according to claim 1 or 2, wherein the filament constituting the fiber sheet is made of an aramid fiber.   The said primer and the said fiber adhesive are transparent or translucent, The repair method of the concrete structure of any one of Claims 1-3 characterized by the above-mentioned. The coating amount of the primer repair method of claim 1 concrete structure according to any one of claims 4, characterized in that a 0.05 to 0.5 / m ^2. The coating amount of the fiber adhesive, method of repairing a concrete structure according to any one of claims 1 to claim 5, characterized in that the 0.4~1.1kg / m ^2. In the hole provided in the concrete structure, a holder made of stainless steel pan and expanded bottom anchor body is installed, and measured according to JIS K 7117-1 in the gap between the expanded bottom anchor body and the hole wall of the concrete structure. Attached with an acrylic resin filler having a viscosity at 20 ° C. and a viscosity of 20 rpm of 50,000 to 150,000 mPa · s, and a tensile shear bond strength with stainless steel of 5 N / mm ² or more, and fixing the primer to the fiber The method for repairing a concrete structure according to any one of claims 1 to 6, wherein the fiber sheet bonded with an agent is fixed.   The method for repairing a concrete structure according to claim 7, wherein the dish of the holding device is covered with an acrylic resin filler or a fiber adhesive, and the dish surface is shielded from the atmosphere. The method for repairing a concrete structure according to claim 8, wherein the tensile shear bond strength of the fiber adhesive with stainless steel is 5 N / mm ² or more.   A concrete structure repaired by the method for repairing a concrete structure according to any one of claims 1 to 9.

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