JP2014208968A - Coupling method of continuous fiber sheet - Google Patents

Abstract

[PROBLEMS] In a repair and reinforcement method using a continuous fiber sheet in the construction field, it is possible to easily perform joint construction and to improve the stability of joint strength by suppressing variation in joint strength due to the skill of construction workers. A method for jointing continuous fiber sheets is provided. A joint method for a continuous fiber sheet of an on-site impregnation type used for repair and reinforcement of a structure, wherein a belt-like sheet is installed on the surface of a joint position of a first continuous fiber sheet before the impregnation resin is cured, A joint method for continuous fiber sheets, comprising removing the sheet and forming irregularities on the surface, and then attaching a second continuous fiber sheet to the surface. [Selection] Figure 2

Description

  The present invention relates to a joint method for joining continuous fiber sheets used as a repair and reinforcement method for a deteriorated construction.

In the construction field, as a repair / reinforcement method for structures that have become load-bearing nonconforming due to cracks, deterioration over time, application changes, etc., resin is mainly used on continuous fiber sheets with a fiber amount of 200 to 400 g / m ^2. A method of impregnating and curing and bonding to a reinforced structure has been used. Under the present circumstances, the joint joining which overlap | superposed the edge parts of the continuous fiber sheet was generally used for reinforcement by the continuous fiber sheet. In recent years, in order to shorten the reinforcing process and reduce the amount of resin used, a continuous fiber sheet with a high basis weight in which the fiber amount of the continuous fiber sheet exceeds 450 g / m ² or more has been adopted.

  However, since the continuous fabric sheet with a high basis weight is thick, a step is generated more than the conventional continuous fiber sheet when performing joint joining. When stress is generated in the continuous fiber sheet, a moment is generated in the joint due to this step, and a peeling force (stripping force in the vertical direction) is generated in the joint, and peeling occurs in the joint at a stress lower than usual. It was an issue.

  Furthermore, in addition to problems in reducing the strength of the joint, as the amount of resin increases due to on-site construction, the thickness between the continuous fiber sheets in the joint becomes less likely to be equal in both the thickness direction and the in-plane direction. As a result, the variation in joint strength is also a problem.

  As described in Non-Patent Document 1, as a technique related to the joining of continuous fiber sheets of in-situ impregnation type, when a whitening phenomenon occurs in the joint portion, the surface of the joint portion is roughened using sandpaper or the like. A method of adhering to the lower continuous fiber sheet layer has been proposed.

  In addition, as a method for improving the adhesive force of the joint part of the joint part other than the construction field, a conventional technique related to surface treatment has been proposed. As a method for improving the adhesive strength of the joint when joining FRP materials, for example, as described in Patent Document 1, a method of simultaneously performing corona treatment and leather irradiation on the joint surface of FRP, or Patent Document 2 As described, a method has been proposed in which the water-soluble filler dispersed in the molding material is removed by water treatment and roughened.

JP 1993-220444 JP 2012-197358 A

Textbook for workshop on continuous fiber reinforcement construction for continuous fiber construction managers and installers (General Association for Textile Repair and Reinforcement)

  However, although the technique disclosed in Non-Patent Document 1 is a technique that has been used in the past, when the joint locations are scattered or the joint range is wide, it takes time to perform the roughening process. In addition, a difference in the skill of the installer is likely to occur. Furthermore, there is a concern that the continuous fiber sheet may be damaged if the sandpaper is applied too much.

  Patent Document 1 requires a large-scale apparatus for surface treatment using electric energy and light energy, and is a process under a strictly controlled environment. It becomes difficult to apply at the construction site in such various environments.

  Furthermore, for Patent Document 2, it is necessary to apply a water-soluble filler, and the filler is dissolved with water. However, there is a high possibility that the water used here remains on the joint surface, ensuring stable joint strength. Is difficult.

  In view of the above-mentioned problems, the present invention is a repair and reinforcement method using a continuous fiber sheet in the construction field, the joint strength is improved, the joint construction can be easily performed, and the joint strength variation due to the skill of construction workers It aims at providing the joint method of the continuous fiber sheets to suppress.

(1) A joint method for an on-site impregnated continuous fiber sheet used for repair and reinforcement of a structure, wherein a belt-like sheet is installed on the surface of the joint position of the first continuous fiber sheet before the impregnation resin is cured, A joint method for continuous fiber sheets, comprising removing the sheet and forming irregularities on the surface, and then attaching a second continuous fiber sheet to the surface.
(2) The continuous fiber sheet joint method according to (1), wherein the belt-like sheet is removed after the impregnated resin of the first continuous fiber sheet is cured.
(3) The continuous fiber sheet joint method according to (1) or (2), wherein the belt-like sheet is a fiber sheet or a film sheet.
(4) The joint method for continuous fiber sheets according to (3), wherein the fiber-based sheet has a mesh shape formed at intervals of 0.5 to 5 mm.
(5) The joint method for continuous fiber sheets according to (3), wherein at least one surface of the film-based sheet is embossed.

  According to the present invention, in the repair and reinforcement method using a continuous fiber sheet in the construction field, it is possible to easily perform joint construction. Furthermore, it is possible to improve the stability of the joint strength by suppressing the variation in joint strength due to the skill of the construction worker.

It is a schematic diagram which shows the process of forming the joint method of the continuous fiber sheet reinforced on the surface of the concrete structure which concerns on this invention. It is an expanded longitudinal cross-sectional view of the joint part using the joint method of this invention. It is a schematic diagram of the mesh shape of a strip-shaped sheet. It is a schematic diagram which shows the shape of a test body. It is a cutting | disconnection observation photograph of the joint part of the test body 1 (UT-No). It is a disconnection observation photograph of the joint part of test body 2 (UT-PP).

  A continuous fiber sheet joint method according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a process of forming a joint method of continuous fiber sheets reinforced on the surface of a concrete structure. Hereafter, the process of forming the joint method of this invention is demonstrated in order.

  First, as Step 1, the concrete structure 9 is freed of dirt such as oil, dust, debris, etc. adhering to the base in order to improve the adhesive strength. Apply in the order of land modifiers. At this time, it is preferable to use the same kind of resin as the impregnating resin forming the FRP as the primer or the unevenness adjusting material.

Next, as process 2, undercoat impregnation resin 1 is applied to first continuous fiber sheet 2. The coating amount is determined according to the basis weight of the first continuous fiber sheet 2 to be installed. For example, in the case of a high basis weight carbon fiber sheet 600 g / m ² , 400 g / m ^{2 to} 800 g / m ² of impregnating resin is required. It becomes. The resin amount of the first undercoat impregnated resin 1 varies depending on the basis weight of the carbon fiber sheet, but if it is less than 400 g / m ² , the carbon fiber sheet may not be sufficiently impregnated and the predetermined strength may not be exhibited. In addition, if it exceeds 800 g / m ² , the thickness of the first undercoat impregnated resin 1 itself increases, which may cause problems in construction such as resin sag and unevenness of resin, so that a sufficient reinforcing effect may not be achieved. There is.

As the material 2 of the first continuous fiber sheet used in the present invention, various reinforcing fibers can be used. For example, at least one continuous fiber can be used from the group consisting of carbon fiber, glass fiber, aramid fiber, polyparaphenylene benzoxozole (PBO) fiber and high-strength polyester fiber. Among these, the use of carbon fibers having a tensile elastic modulus in the range of 100 GPa to 800 GPa is preferable because the rigidity can be improved more efficiently and the reinforcing effect is easily exhibited. In the case of using a carbon fiber sheet, the basis weight is preferably higher basis weight of ^{450~900g / m 2, 500~750g / m} 2 is more preferable. When the basis weight increases, the amount of continuous fibers per unit area increases, a reinforcing effect can be exhibited, and the construction period can be shortened. On the other hand, if the basis weight is too high, it becomes difficult to impregnate the resin between the fibers, and there is a possibility that strength and the like cannot be sufficiently developed due to non-impregnation.

  As the impregnating resin, it is preferable to use a synthetic resin adhesive. For example, at least one resin selected from the group consisting of epoxy resins, acrylic resins, vinyl ester resins, phenol resins, and unsaturated polyester resins can be used. In consideration of stability, it is more preferable to use an epoxy resin or an acrylic resin.

  Next, as step 3, the first continuous fiber sheet 2 is attached to the surface of the concrete structure 9 pretreated in step 1. After the first continuous fiber sheet 2 is pasted, the first undercoat impregnated resin 1 oozes out from the gap between the first continuous fiber sheets 2. Leave until hardened to the extent that it does not slip.

  Then, the air existing in the fiber bundle which comprises the 1st continuous fiber sheet 2 is squeezed out using an impregnation roller or a defoaming roller.

Next, as step 4, the first top coat impregnating resin 3 is applied to the upper part of the first continuous fiber sheet 2 impregnated in step 2, and the impregnation operation is performed again. Although coating amount determined in accordance with the first basis weight of the continuous fiber sheet 2 to be installed, for example, in the case of high basis weight carbon fiber sheets 600 g / ^{m 2,} it required impregnating resin of 200g / ^{m 2} ~400g / m 2 Become. In the case of topcoat impregnated resin, the basecoat impregnated resin is applied to the surface with the resin in the continuous fiber sheet, so the amount of resin is less than that of the basecoat impregnated resin, and the moment generated at the joint step is reduced as described later. It is preferable that the reinforcing effect by the continuous fiber sheet is sufficiently developed.

  Next, as step 5, the belt-like sheet 5 is installed on the surface of the joint position of the first continuous fiber sheet 2 before the first top coat impregnating resin 3 is cured. For the belt-like sheet 5, a fiber-based sheet or a film-based sheet can be used.

  It is preferable that the fiber-based sheet has a mesh shape formed at intervals of 0.5 to 5 mm. More preferably, it is 0.75-3 mm. The shape of the mesh may be the triangular shape or the quadrangular shape shown in FIG. But you can. As for the fiber diameter which comprises a mesh, 0.01-0.1 mm is preferable. More preferably, it is 0.025-0.075 mm. Moreover, it is preferable that a fiber-type sheet | seat is a peel ply material so that it can peel easily from top coat impregnation resin 3 easily. The base material of the peel ply material is preferably a nylon woven fabric or a polyester woven fabric. The base material is an acid-modified polyolefin resin containing 1 to 10% of a silicone resin or an acid component, and 100 parts by mass of the acid-modified polyolefin resin. More preferred are those coated with 1 to 50 parts by mass of a crosslinking agent and a resin contained therein.

  The film-based sheet is embossed on at least one side, and the embossed shape is spherical, triangular pyramid, quadrangular pyramid or polygonal cylindrical, and the size is 0.1 to 3 mm. It is preferable that it is the range of these. Polyester and polypropylene are preferable as the base material of the film-based sheet, and those having the surface of the base material difficult to adhere to the synthetic resin by applying a silicon coating or a release agent are preferable.

  Furthermore, it is preferable that the belt-like sheet 5 described above has a flexibility that does not undergo plastic deformation even when the radius of curvature is curved to about 100 mm. Even when the concrete structure to be reinforced has a curved surface shape, it can be suitably applied.

  In the present invention, the bonding area can be increased by forming the groove portion 4 by surface-treating the joint portion using the belt-like sheet 5 as described above. Furthermore, by using a high basis weight continuous fiber sheet, the basis weight of the impregnating resin is increased, and even if the thickness of the applied impregnating resin is increased, the excess resin of the first topcoat impregnating resin 3 can be removed, Since the thickness can be made thin and uniform, the moment generated at the step of the joint portion can be reduced, and as a result, the joint strength can be improved. Moreover, since the groove part 4 can be formed with an easily peelable fiber-based sheet or an embossed film-based sheet, variation due to the skill of the operator can be suppressed, and the first continuous fiber sheet 2 can be damaged. The surface treatment can be performed without any problem, and the construction period can be shortened as compared with the conventional surface treatment method using sandpaper or the like. Furthermore, by arranging the belt-like sheet 5 at the joint portion of the first continuous fiber sheet 2, the position of the joint portion can be visualized, and construction errors can be reduced.

  Next, as step 6, the belt-like sheet 5 is removed to form the groove 4 (unevenness) on the surface. At this time, the strip-like sheet 5 can be removed even when the first topcoat impregnated resin 3 is uncured. However, in order to keep the shape of the groove portion 4 clear, after the step 6 is finished, After -24 hours or more have elapsed, it is desirable that the first top coat impregnating resin 3 of the first continuous fiber sheet 2 has an initial curing state (a level where no nail mark remains even if the nail is slightly raised). Thereafter, when both the first undercoat resin 1 and the first overcoat resin 3 are sufficiently cured, the first FRP 100 is formed.

  Finally, as step 7, using the same procedure as the procedure for forming the first FRP 100, using the second impregnation resin (undercoat) 6, the second continuous fiber sheet 8, and the second impregnation resin (overcoat) 7, A second FRP 200 is formed. In addition, when adding FRP further, a joint part is formed in each FRP by repeating Step 1 to Step 6, and further FRP is formed, and an FRP reinforcing material having a necessary length is provided. Can do.

  FIG. 2 shows an enlarged longitudinal sectional view of the joint portion obtained by the present invention. Groove portion 4 formed of concavities and convexities connected to a joint portion of a first FRP (fiber reinforced plastic) 100 composed of a first continuous fiber sheet 2, a first impregnation resin (undercoat) 1, and a first impregnation resin (overcoat) 3. The second continuous fiber sheet 8, the second impregnation resin (undercoat) 6, and the second FRP 200 made of the second impregnation resin (overcoat) 7 are joined. By providing the groove 4 in advance in this way, the location where the next FRP is formed becomes clear, and the adhesion area increases, so that the impregnated resin can be firmly bonded to each other, and peeling from the joint portion also occurs. It becomes difficult to do. Moreover, even if a part is peeled and an unbonded part is generated between the continuous fiber sheets, the part that is not peeled can be firmly bonded, so that the effect of reducing the reinforcing effect of the concrete structure can be reduced. .

  Next, the joint method of the continuous fiber sheet of the present invention will be described in detail based on examples. In addition, this invention is not restrict | limited at all by a present Example.

(1) Joint test body The carbon fiber sheet used for the joint test body was manufactured by Toray Industries, Inc. “Torayca (registered trademark)” Cross UT70-60G (catalog value: CF basis weight 600 g / m ² , tensile strength 3400 MPa or more, The elastic modulus is 245 GPa. As the impregnating resin forming FRP, Toho Earth Tech Co., Ltd. impregnating resin CF-5P was used. Moreover, the strip | belt-shaped sheet | seat used for a joint part was made into a fiber-type sheet | seat, and B-4444 by RICHMOND Co., Ltd. was used.

(2) Specimen preparation method First, 600 g / m ² of an impregnating resin is primed on a release film (release PET film manufactured by Izumi Co., Ltd .: 125-SP1080), and a first continuous fiber sheet is applied thereon. The impregnating resin was impregnated and defoamed while maintaining the linearity of the fiber axis. Furthermore, 600 g / m ^{2 of} the first topcoat impregnating resin was applied to the upper part of the first continuous fiber sheet, and the impregnation operation was performed again.

  Then, about the test body 1 "UT-No", the strip | belt-shaped sheet | seat was installed in the width | variety 10cm which hits the joint part of a 1st continuous fiber sheet and a 2nd continuous fiber sheet in the state which impregnating resin has not hardened. After installing the belt-like sheet, curing was performed for 24 hours, and after confirming that the impregnating resin was cured, the belt-like sheet was removed, and a groove portion was created across the surface of the joint portion of the first continuous fiber sheet. For Specimen 2 “UT-PP”, a strip sheet was not installed at the joint between the first continuous fiber sheet and the second continuous fiber sheet, and the 24-hour curing was performed as it was.

  A second FRP sheet was formed to wrap 100 mm with the manufactured first FRP (“UT-No”, “UT-PP”). The second FRP was molded in the same order as the first continuous fiber sheet was formed by applying the impregnated resin undercoat, setting the second continuous fiber sheet, and then applying the impregnated resin overcoat. .

  After the second FRP impregnation operation, after curing for one week, confirm that the second FRP is cured, and attach a tensile test tab made of glass fiber reinforced plastic using an epoxy adhesive. It was. Thereafter, using a diamond cutter, a strip-shaped joint test piece having a shape shown in FIG. 4 was prepared by cutting out to a width of 12.5 mm ± 2.5 mm and a length of 200 mm or more.

(3) Test Method The joint strength was tested based on “Joint Test Method JSCE-E542-2007 for Continuous Fiber Sheets” described in the Japan Standards for Concrete Standard Specification. Specifically, the tester used was a static mechanical tester Instron (maximum load 500 kN), and both ends of the joint test piece were attached to the chuck portion of the static mechanical tester, and a tensile test was performed. During the test, the loading load was increased at a loading speed of 2 mm / min, and loading was performed until the joint specimen was broken.

(4) Test results Table 1 shows the joint test results.

  As shown in Table 1, it was confirmed that the joint strength was improved by using the fiber sheet shown in the present invention for the joint work. In addition, the variation in joint strength could be suppressed by about 1/4, and the effect of exhibiting stable joint strength could be confirmed. As a result of statistical processing, it was also confirmed that the joint strength at 99.6% reliability was clearly improved.

  FIG. 5 shows a cross-sectional observation photograph of the joint portion of UT-No, and FIG. 6 shows a cross-sectional observation photograph of UT-PP. From these cross-sectional observation photographs, compared with UT-No, UT-PP was able to make the unevenness of the boundary between the first FRP and the second FRP finer and uniform. In other words, finely formed at regular intervals, the groove portion increases the adhesion area, and the joint surface can be made horizontal and uniform in the fiber arrangement direction, thereby improving the joint strength and obtaining a stable joint strength.

1 First impregnating resin (undercoat)
2 First continuous fiber sheet 3 First impregnating resin (overcoat)
4 Groove 5 Strip sheet 6 Second impregnating resin (undercoat)
7 Second impregnating resin (overcoat)
8 Second continuous fiber sheet 9 Concrete structure 10 Ground treatment material 100 First FRP
200 Second FRP

Claims (5)

A joint method for an on-site impregnated continuous fiber sheet used for repair and reinforcement of a structure, wherein a belt-like sheet is installed on the surface of the joint position of the first continuous fiber sheet before the impregnation resin is cured, and the belt-like sheet is removed. And forming a concavity and convexity on the surface, and then bonding a second continuous fiber sheet to the surface. The joint method for a continuous fiber sheet according to claim 1, wherein the belt-like sheet is removed after the impregnating resin of the first continuous fiber sheet is cured. The joint method for continuous fiber sheets according to claim 1 or 2, wherein the belt-like sheet is a fiber sheet or a film sheet. The joint method for a continuous fiber sheet according to claim 3, wherein the fiber-based sheet has a mesh shape formed at intervals of 0.5 to 5 mm. The joint method for continuous fiber sheets according to claim 3, wherein at least one surface of the film-based sheet is embossed.