JP2017223093A - Method and structure for reinforcing concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concurrently fulfill three requirements, that is, an increase in adhesive strength between a fiber sheet and a concrete structure, the thorough impregnation of the inside of the fiber sheet with a resin, and the capability to sufficiently exert strength and an elastic modulus, intrinsic in the fiber sheet.SOLUTION: A bidirectional bicomponent fiber sheet 10 is used in which a warp group fabric 10A and a weft group fabric 10B are different in a fineness and a ridge distance between fiber groups. The one fabric 10B is stuck on a surface of a concrete structure 40 coated with an undercoat resin 51. Subsequently, the other fabric 10A is coated with a top coat resin 52 and impregnated therewith.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technology for reinforcing concrete structures such as bridge slabs, beams, piers, and tunnel lining concrete, and in particular, a concrete structure in which a bi-directional composite fiber sheet is attached to the surface of a concrete structure for reinforcement. The present invention relates to a reinforcing method and a reinforcing structure thereof.

As a repairing and reinforcing method for cracks and damage to road bridges and RC floor slabs, a reinforcing method is known in which a fiber sheet is bonded to a reinforcing surface with a resin.
Patent Document 1 discloses that a fiber sheet in a dry state is attached to the surface of a concrete structure coated with a quick-drying primer, and a quick-drying top coat resin is applied to the fiber sheet and impregnated.
In Patent Document 2, a fiber sheet impregnated with resin in advance (preliminary impregnation) is attached to the surface of a concrete structure subjected to primer treatment, and then an overcoat resin is applied to impregnate the resin in the fiber sheet ( Replenishment impregnation).
In the case where the concrete structure is a bridge slab, the worker applies the primer and the resin in an upward posture, and therefore there is a certain limitation on the application thickness of the adhesive resin such as the primer and the primer resin.
Further, as disclosed in Patent Document 2, the fiber sheet has a woven fabric such as a basket weave which has voids at the top, bottom, left, and right of the intersection where warp yarns and weft yarns are alternately interlaced to improve resin impregnation. The fiber sheet made from is used.

JP 2009-150085 A JP 2000-199208 A

The conventional technology for reinforcing concrete structures has the following problems.
<1> In order to enhance the reinforcing performance by the fiber sheet, a) increase the adhesive force between the fiber sheet and the concrete structure, b) impregnate the resin without leaving the fiber sheet, and c) the fiber sheet inherently exists. It is important to satisfy the three requirements of sufficient strength and elasticity.
The reinforcing techniques disclosed in Patent Documents 1 and 2 cannot simultaneously satisfy the above three requirements.
<2> Since the reinforcing technique disclosed in Patent Document 1 only attaches a dry fiber sheet to the primer application surface, the adhesion of the fiber sheet is likely to be insufficient, and the above requirement a) can be achieved. Have difficulty.
<3> Although the reinforcement technique disclosed in Patent Document 2 can achieve the above-described requirement a) by pre-impregnating the fiber sheet with a shortage of the primer resin, the above-described requirement c) can be achieved. Have difficulty.
The reason is that the fiber sheet disclosed in Patent Document 2 has a warp and a weft that are interlaced in a state of being largely bent into a substantially S shape, so that the knitted fabric has sufficient original strength and elastic modulus. It is because it cannot be demonstrated.
<4> In order to compensate for the shortage of the proof strength of the fiber sheet, the fabric sheet is increased in weight per unit area. However, increasing the fabric weight increases the thickness and weight of the fiber sheet and increases the cost. I have a problem.
<5> When the gap between the fiber groups on the front and back surfaces of the fiber sheet is knitted largely, the primer resin impregnates the gap between the fibers and requires a large amount of primer resin.
On the other hand, as described above, there is a certain limit to the coating thickness of the primer resin on the lower surface of the concrete structure, and it is difficult to ensure the coating thickness of the primer resin assuming suction.
Therefore, there is a problem that the adhesive resin on the surface of the concrete structure tends to be insufficient and the adhesive strength of the fiber sheet is insufficient.
<6> On the other hand, when the gaps between the fiber groups on the front and back surfaces of the fiber sheet are knitted small, there is a problem that the impregnation property of the resin between the fibers decreases and the reinforcing effect by the fiber sheet decreases.

  The present invention has been made in view of the above points. The purpose of the present invention is to a) increase the adhesive force between the fiber sheet and the concrete structure, and b) impregnate the resin into the fiber sheet without any wrinkles. C) It is to provide a reinforcing technique for a concrete structure capable of simultaneously satisfying the three requirements that the fiber sheet originally has sufficient strength and elasticity.

The present invention relates to a method for reinforcing a concrete structure in which a fiber sheet is attached to the surface of the concrete structure to reinforce, and a plurality of warp group knitted fabrics in which a plurality of warp yarns are arranged in parallel at intervals, and a plurality of weft yarns Are bound together by a plurality of knitting yarns, and at least the fiber group crease spacing between the warp group knitted fabric and the weft group knitted fabric is Using a bi-directional composite fiber sheet, applying a primer resin to the surface of a concrete structure, and either a warp group knitted fabric or a weft group knitted fabric in which the thread spacing of the yarn is arranged narrowly A step of attaching the knitted fabric to the surface of the concrete structure, and a step of applying and impregnating a top coat resin to either the warp group knitted fabric or the weft group knitted fabric in which the yarn spacing is widely arranged. It is characterized by comprising.
Further, the present invention provides a concrete structure in which an undercoat resin applied to the surface of a concrete structure and a composite fiber sheet attached to the undercoat resin are laminated and the composite fiber sheet is impregnated with an overcoat resin. A structure for reinforcing an object, wherein a plurality of warp group knitted fabrics in which a plurality of warp yarns are arranged in parallel with a gap between them and a plurality of weft group knitted fabrics in which a plurality of weft yarns are arranged in parallel with a gap between them. A bi-directional composite fiber sheet in which the warp group knitted fabric and the weft group knitted fabric have different wrinkle intervals, and the yarn wrinkle intervals are arranged narrowly. One of the warp group knitted fabric or the weft group knitted fabric is bonded to the surface of the concrete structure through an undercoat resin, The top coat is applied to one of the weft group knitted fabrics. Wherein the fat is impregnated.
In another embodiment of the present invention, a bi-directional composite fiber sheet in which the fineness of the warp group knitted fabric and the weft group knitted fabric and the wrinkle intervals of the fiber groups are different is used.
In another embodiment of the present invention, the total yarn amount of either the warp group knitted fabric or the weft group knitted fabric in which the fineness is small and the yarn wrinkle spacing is narrow, the fineness is large, and The total yarn amount of either the warp group knitted fabric or the weft group knitted fabric in which the yarn wrinkles are widely arranged is in the same relationship.
In another embodiment of the present invention, the warp group weft fabric and the weft group knitted fabric constituting the composite fiber sheet are made of aramid fibers, and the proof stresses in the warp direction and the weft direction are 150 kN / m or more, respectively.
In another embodiment of the present invention, the basis weight of the warp group knitted fabric and the weft group knitted fabric constituting the composite fiber sheet is 300 to 1300 g / m ² .

The present invention uses a bi-directional composite fiber sheet in which the warp spacing of the fiber groups of the warp group knitted fabric and the weft group knitted fabric is different, and does not require pre-impregnation just by applying a resin to the concrete structure, Since the composite fiber sheet can be affixed to the surface of a concrete structure, it has been difficult to achieve a) to increase the adhesive force between the composite fiber sheet and the concrete structure, and b) without any trouble into the composite fiber sheet. The three requirements of impregnating the resin and c) sufficiently exhibiting the strength and elastic modulus inherent to the composite fiber sheet can be satisfied at the same time.
Therefore, the reinforcing effect of the concrete structure can be remarkably enhanced as compared with the conventional case.

Partial sectional view of the surface of a concrete structure with a composite fiber sheet FIG. 3 is a plan model diagram of a composite fiber sheet with a part omitted, where (a) is a model diagram of a warp group knitted fabric, and (b) is a model diagram of a weft group knitted fabric. Image of warp and weft, which are fiber groups of a composite fiber sheet Organization chart of composite fiber sheet Enlarged cross-sectional view of the bonded part of a concrete structure coated with primer resin Expanded cross-sectional view of the bonded part of a concrete structure with a composite fiber sheet Enlarged cross-sectional view of the adhesive part of a concrete structure coated with a top coat resin

  Hereinafter, the present invention will be described with reference to the drawings.

<1> Composite Fiber Sheet The composite fiber sheet 10 used in the present invention has a warp group knitted fabric 10A in which a plurality of warp yarns 20 are arranged in parallel in the Y direction with an interval, and a plurality of weft yarns 30 at an interval. Through the weft group knitted fabric 10B arranged in parallel in the X direction, and a plurality of knitting yarns (coated auxiliary fibers 11, Bidirectional fiber sheet comprising entanglement auxiliary fibers 12).
The fiber group of the warp yarn 20 and the weft yarn 30 has a fiber group in which reinforcing fibers are arranged in parallel as one unit, and one unit of fiber group is arranged in a hook shape with a predetermined interval.

In the warp group knitted fabric 10A and the weft group knitted fabric 10B, at least the crease spacing of the fiber groups is different.
In this example, a description will be given of a form in which two factors of the fineness of the warp group knitted fabric 10A and the weft group knitted fabric 10B and the heel spacing of the fiber groups are different.
This will be described with reference to FIGS. 2A is a model diagram of the warp group knitted fabric 10A of the composite fiber sheet 10, and FIG. 2B is a model diagram of the weft group knitted fabric 10B. The dimensional relationship between the warp yarn 20 and the weft yarn 30 intersecting with FIG. A model diagram is shown.
Coated auxiliary fibers 11 are arranged in a warp knitted fabric (Russell network) by entanglement auxiliary fibers 12 on the warp group knitted fabric 10A of the composite fiber sheet 10, and the weft group knitted fabric 10B has the same kind as the coated auxiliary fibers 11. The reinforcing fiber group is inserted as a weft 30 in a hook shape.
The composite fiber sheet 10 is composed of two knitted fabric sheets that are aligned in one direction so as to be orthogonal to each other in the vertical and horizontal directions, and the two sheets are bound with a knitting yarn. ) May be used.

<1.1> Reason why warp and weft are not mixed The fiber group of the warp 20 and the fiber group of the weft 30 are orthogonal to each other, but the fiber group of the warp 20 and the weft 30 is interlaced in a substantially S-shaped bent state. Not done.
The fiber group of the warp 20 and the fiber group of the weft 30 are juxtaposed in a straight state.
The fact that the warp yarn 20 and the weft yarn 30 are juxtaposed without crossing each other avoids the warp yarn and the weft yarn of the composite fiber sheet 10 from being largely bent into a substantially S-shape, and the strength and elasticity of the composite fiber sheet 10 that it originally has. This is because the sheet thickness of the composite fiber sheet 10 is reduced.

<1.2> Referring to warp group knitted fabric Figure 3, the warp group knitted fabric 10A includes a plurality of warp yarns 20 having a diameter d ₁ are arranged in parallel via a gap G _1.

<1.3> Referring to weft group knitted fabric Figure 3, the weft group knitted fabric 10B has a plurality of weft yarns 30 having a diameter d ₂ are arranged in parallel via a gap G _2.

<1.4> Relationship between Warp and Weft Diameter and Interval Warp 20 and weft 30 have the following relationship between the diameters d ₁ and d ₂ and the heel intervals G ₁ and G ₂ .
That is, the diameter d ₂ of the weft 30 is smaller than the diameter d _{1 of the} warp 20, and the heel distance G ₂ of the weft 30 is smaller than the heel distance G ₁ of the warp 20.
In other words, the weft group knitted fabric 10B reduces the gap between the intercostals and the thickness of the yarn to reduce the yarn fineness of the weft 30. The warp group knitted fabric 10A has a wide warp interval between the warp yarns 20 to promote resin impregnation. It is.

<1.5> Relationship Between Yarn Amounts The total yarn amount (weight per unit area) of the warp yarn 20 and the weft yarn 30 constituting the warp yarn group knitted fabric 10A and the weft yarn group knitted fabric 10B is the heel spacing G ₁ , G ₂ Etc. are selected as appropriate.
For example, the total yarn amount of the warp yarn 20 having a large fineness and a wide wrinkle interval is equal to the total yarn amount of the weft 30 having a small fineness and a narrow wrinkle interval. Then, the strength of the two knitted fabrics 10A and 10B can be made the same, and the overall strength of the composite fiber sheet 10 can be made uniform.

<1.6> Examples of Fiber Sheet Materials As fibers used in the composite fiber sheet 10, in addition to organic fibers such as aramid fibers, carbon fibers, glass fibers, and the like, various conventionally known chemical fibers can be used. These can be used alone or in combination of two or more.
The yield strength of the composite fiber sheet 10 is preferably in the range of 150 to 900 kN / m in both the warp direction and the weft direction.
If the proof stress is below the range, the reinforcing effect is small. Conversely, if the proof stress exceeds the range, the sheet weight (fiber amount) is too large, and it becomes difficult to impregnate the resin.
The yield strength of the composite fiber sheet 10 is preferably 250 to 700 kN / m, and more preferably 350 to 600 kN / m, within the above range.
Also, the basis weight of the composite fiber warp group knitted fabric 10A constituting the sheets 10 and weft groups knitted fabric 10B is preferably from 300~1300g / m ^2, more preferably 450~1100g / m ^2, more preferably 550 to 900 g / m ² .
The basis weight in the present invention is measured in accordance with the method described in “6.4 Mass per unit area” of JIS L 1096 “General Textile Testing Method” and is expressed in absolute dry weight per unit area. It is.

<1.7> Knitting Yarn The warp yarn 20 and the weft yarn 30 are bound together by a warp knitting structure via a knitting yarn composed of the covering auxiliary fiber 11 and the entanglement auxiliary fiber 12.

<1.8> Example of Fiber Sheet Structure FIG. 4 shows an example of a structure diagram of the composite fiber sheet 10.
FIG. 4 shows a structure diagram of the composite fiber sheet 10 in which the weft 30 is not shown. (A) shows a structure diagram of the warp 20 and the covering auxiliary fiber 11, and (b) shows an auxiliary fiber 12 entangled with the warp 20. Shows the organization chart.
A plurality of wefts 30 (not shown) are inserted into the ground texture portion on the front side of the warp group knitted fabric 10A.
The composite fiber sheet 10 can be knitted using, for example, a weft insertion Russell machine.

<1.9> Size Example of Fiber Sheet The size of the composite fiber sheet 10 is not particularly limited, and is set within a range of, for example, a width of 0.2 to 2 m and a length of 20 to 100 m from the viewpoint of handleability.

<2> Resin In the present invention, a primer 50 for base treatment, an undercoat resin 51, and an overcoat resin 52 are used.
For these resins 50 to 52, for example, a room-temperature curable resin such as an epoxy resin, a vinyl ester resin, a methacrylic resin, a polyester resin, a urethane resin, or an acrylic resin can be used. The undercoat resin 51 and the overcoat resin 52 are composed of the composite fiber sheet 10. In view of the impregnation property, a resin having a curing time (including tack-free time) of 2.5 hours or more is preferable.
As for the resin amount of the undercoat resin 51, if the basis weight is 1.5 to 3.0 times the weight of the composite fiber sheet 10 on the weft group knitted fabric 10B side, the shortage of the undercoat resin 51 is suppressed and the composite fiber sheet 10 is suppressed. It is possible to secure a good adhesive force between the steel and the concrete structure 40.
With respect to the resin amount of the top coat resin 52, if the basis weight is 1.0 to 2.5 times the basis weight on the warp group knitted fabric 10A side of the composite fiber sheet 10, the top coat resin 52 is sufficiently impregnated, and the excess It is possible to eliminate waste of unnecessary resin.
The amount of resin used is preferably in the range of 400~2500g / ^{m 2.}
Among them, it is preferably from 500~1800g / ^{m 2,} and more preferably 900~1800g / ^{m 2.}
For example, a fiber sheet having a yield strength of 50 ton / m in both the warp and weft directions and a basis weight of 700 g / m ² shows optimum workability when the amount of resin used is 1400 g / m ² .

[Construction method]
The construction method for affixing and repairing the composite fiber sheet 10 on the lower surface of the concrete structure 40 will be described with reference to FIGS.
In addition, the composite fiber sheet 10 in FIGS. 5-7 has shown the cross section fractured | ruptured in the position straddling both the threads 20 and 30. FIG.

<1> Primer application process (FIG. 5)
After removing the foreign matter on the surface (lower surface) 41 of the concrete structure 40, a primer 50 such as a room temperature curable epoxy resin is applied.

<2> Undercoat resin coating process (FIG. 5)
Next, the primer resin 51 of a predetermined resin amount is uniformly applied to the surface of the primer 50.

<3> Fiber sheet pasting step (FIGS. 5 and 6)
The composite fiber sheet 10 is pasted before the undercoat resin 51 is cured.
The composite fiber sheet 10 is used in a dry state without being pre-impregnated with resin.
In the warp group knitted fabric 10A and the weft group knitted fabric 10B of the composite fiber sheet 10, the fineness and the crease spacing of the fiber groups are different.
So when pasting the composite fiber sheet 10 is pasted weft group knitted fabric 10B of ridges gap G ₂ are arranged in closely spaced fiber groups (weft 30) towards the concrete structure 40.
By affixing the weft group knitted fabric 10B side to the concrete structure 40, the undercoat resin 51 penetrates into the inside of the weft 30 and the undercoat resin 51 penetrates into the gaps between the adjacent wefts 30.
Since the weft group knitted fabric 10B of the composite fiber sheet 10 is densely formed with a narrow gap between the fiber groups of the weft 30 and a small gap, no extra resin is required, so that there is no shortage of the primer resin 51.
In other words, the amount of penetration of the undercoat resin 51 into the weft group knitted fabric 10B can be minimized by the amount by which the knitted fabric thickness and heel spacing of the weft group knitted fabric 10B are smaller than those of the warp group knitted fabric 10A.
The lack of deficiency in the undercoat resin 51 means that the undercoat resin 51 does not penetrate excessively beyond the weft group knitted fabric 10B and into the warp group knitted fabric 10A. The undercoat resin 51 corresponds to the weft group knitted fabric 10B. What is necessary is just to apply the minimum amount of penetration.
After the composite fiber sheet 10 is attached, it is rolled with a roller or the like.
For example, when using a fiber sheet in which the fineness and warp spacing of the warp group knitted fabric 10A are formed in the same form as the weft group knitted fabric 10B, the penetration amount of the undercoat resin 51 and the overcoat resin 52 can be suppressed. It is expected that the impregnation property deteriorates and adversely affects the strength as FRP.
By using the composite fiber sheet 10 in which the warp group knitted fabric 10A having high air permeability is laminated on the weft group knitted fabric 10B, the generation of bubbles at the interface can be more effectively suppressed, and the adhesiveness to the concrete structure 10 can be suppressed. Can solve the problem.

<4> Application process of top coating resin (FIG. 7)
Finally, an overcoat resin 52 having a predetermined resin amount is applied to the surface of the composite fiber sheet 10.
Since the warp group knitted fabric 10A excellent in resin impregnation property is located on the surface side of the composite fiber sheet 10, it is possible to impregnate the overcoat resin 52 over the entire area of the warp group knitted fabric 10A.
As described above, since the undercoat resin 51 is impregnated in the entire area of the weft group knitted fabric 10B of the composite fiber sheet 10, the amount of the resin necessary for the overcoat resin 52 to be impregnated only into the warp group knitted fabric 10A is sufficient. .
Thus, the FRP sheet is formed by impregnating the undercoat resin 51 and the overcoat resin 52 over the entire area of the composite fiber sheet 10.
In addition, when laminating | stacking the some composite fiber sheet 10, what is necessary is just to perform the sticking process of the above-mentioned composite fiber sheet 10, and the application | coating process of the overcoat resin 52 repeatedly.

<5> Reason for Less Use of Resin In the present invention, the amount of resin used can be reduced as compared with the conventional technique in which a conventional basket woven fiber sheet is attached.
One of the reasons is that the fiber group of the warp 20 and the fiber group of the weft 30 constituting the composite fiber sheet 10 are aligned in a straight state.
In a conventional basket-woven fiber sheet, the constituent fibers are interlaced in a state of being largely bent into a substantially S shape, and thus the strength and elastic modulus of the inherently woven fabric cannot be fully exhibited. Furthermore, conventionally, in order to cope with an increase in the basis weight of the fiber sheet, the increase in the basis weight has included a problem that not only the thickness and weight of the fiber sheet increase but also the cost increases.
On the other hand, the composite fiber sheet 10 is less bent than the conventional fiber sheet, and can fully exhibit the strength and elastic modulus, so that the total yarn amount can be reduced. It is possible to reduce the cross-sectional area of 10B.
That is, in the composite fiber sheet 10, the sheet thickness can be reduced as the total yarn amount is reduced, and as the sheet thickness is reduced, the amount of resin for filling the gap is reduced, and the total amount of resin used can be reduced. .

[Resin impregnation test]
The resin fiber impregnation with respect to the composite fiber sheet 10 was tested.

なおアラミド繊維密度は１．４５ｇ／ｃｍ^３である。 <1> Composite fiber sheet Aramid fiber (trade name “Twaron”) manufactured by Teijin Limited is used, the warp is 3220 dtex × 3 (9 / 吋), the weft is 1610 dtex × 3 (18 / 吋) The composite fiber sheet 10 was knitted under the conditions described above. The details of the warp and weft are as follows.

The aramid fiber density is 1.45 g / cm ³ .

Composite fiber sheets 10 and the tensile strength of 2100 N / mm ² or more, the tensile modulus was 98000~138000N / mm ^2.
The design yield strength of the composite fiber sheet 10 was 500 kN / m in the longitudinal direction.

<2> Weight of composite fiber sheet In order to obtain the weight of composite fiber sheet 10, the weights of warp, weft, and knitting yarn of the sheet cut to 500 × 500 mm were measured. The measurement results are as follows.

<3> Resin A room temperature curable epoxy resin “FF Dyne D-90” manufactured by Maeda Kosen Co., Ltd. was used for the undercoat resin and the topcoat resin.

<4> Affixing the composite fiber sheet In order to test the resin impregnation property to the composite fiber sheet, the base resin is 700 g / m ² over a range of 0.85 m × 1.5 m on the lower surface of the RC slab specimen. Was applied.
The weft group knitted fabric of the composite fiber sheet was attached to the undercoat resin so as to contact the surface.
Further, a top coat resin was applied at 700 g / m ² to the warp group knitted fabric corresponding to the lower surface of the composite fiber sheet.

<5> Test Results When the weft group knitted fabric of the composite fiber sheet of the present invention was used as the application surface to the undercoat resin, it was confirmed that the resin undercoat amount was 700 g / m ² and sufficient adhesive strength was exhibited. Furthermore, it was confirmed that the resin penetrated well into the warp group knitted fabric of the composite fiber sheet.
As a comparative example, when an aramid sheet “Fibra Sheet (registered trademark) (weight per unit area: 870 g / m ² )” manufactured by Fivex Co., Ltd. was used, an undercoat resin of 1300 g / m ² was required.
From this, it was confirmed that the amount of resin used can be greatly reduced in the present invention.

[Tensile strength evaluation test]
Using the composite fiber sheet 10 and a contrast fiber sheet made of woven fabric, the following tensile strength and tensile modulus evaluation tests were performed on each fiber sheet.
The composite fiber sheet 10 has a vertical and horizontal guaranteed yield strength of 500 kN / m, and the contrast fiber sheet has a vertical and horizontal guaranteed yield strength of 490 kN / m.

※設計厚0.240mmとなる目付 0.24mm×1.45g/cm³=348g/m²から算出 <1> About the composite fiber sheet The specification of the composite fiber sheet 10 is as follows.

※ calculated from basis weight ^{0.24mm × 1.45g / cm 3 = 348g} / m 2 to be designed thickness 0.240mm

<2> Contrast fiber sheet The specs of the fibre sheet AK-50 / 50 manufactured by Fivex Co., Ltd., which is a contrast fiber sheet, are as follows.

<3> Test Results The test results of the tensile strength and tensile modulus of the composite fiber sheet 10 are as follows.

<4> Consideration When the guaranteed yield strength is 500 kN / m, the design thickness is 0.24 mm, and the composite fiber sheet 10 is designed accordingly.
In the case of the composite fiber sheet 10 made into FRP, when the basis weight is 700 g / m ² , it has become clear that sufficient strength and elastic modulus can be obtained from the tensile test results.
On the other hand, in the comparative fiber sheet (Fibex Co., Ltd. fibula sheet AK-50 / 50), a weight per unit area of 870 g / m ² is required to obtain a guaranteed proof stress of 490 kN / m in the vertical and horizontal directions of the sheet.
In the case of a contrasting fiber sheet, the reason that the basis weight has to be increased is that the warp and weft yarns are interlaced in a state of being greatly bent into an S shape, and the strength and elastic modulus of the woven fabric originally possessed are This is thought to be because it cannot be demonstrated.

[Other Embodiments]
In the previous composite fiber sheet 10, as shown in FIG. 3, the relationship between the diameters d ₁ and d ₂ of the warp yarn 20 and the weft yarn 30 and the heel spacings G ₁ and G ₂ is as follows (Relationship 1) and (Relationship 2): I explained a case.
(Relationship 1) Diameter d _{1 of} warp 20> Diameter d _{2 of} weft 30
(Relationship 2) Warp spacing G _{1 of} warp yarn 20> Warp spacing G _{2 of} weft yarn 30

Using the composite fiber sheet 10 in the following (Relationship 3) and (Relationship 4) by reversing the relationship between the diameters d ₁ and d ₂ of the warp 20 and the weft 30 and the heel spacings G ₁ and G _2. Is also possible.
(Relationship 3) Diameter d _{1 of} warp 20 <d _{2 of} weft 30
(Relationship 4) Warp spacing G _{1 of} warps 20 <Wrap spacing G _{2 of} wefts 30

  In short, in the warp yarn 20 and the weft yarn 30, the thread diameter of one of the X direction and the Y direction and the thread spacing of the thread are larger than the thread diameter of either the other of the X direction or the Y direction and the thread spacing of the thread. It only needs to be in a small relationship.

10 ··· Composite fiber sheet 10A ··· Warp yarn group knitted fabric 10B · · · Weft yarn group knitted fabric 20 · · · Warp yarn 30 · · · Weft yarn 50 · · · Primer 51 · · .... Undercoat resin 52 ... Overcoat resin

The present invention relates to a method for reinforcing a concrete structure in which a fiber sheet is attached to the surface of the concrete structure to reinforce, and a plurality of warp group knitted fabrics in which a plurality of warp yarns are arranged in parallel at intervals, and a plurality of weft yarns Are joined together with a plurality of knitting yarns, and the knitting ground of either one of the warp group knitting fabric or the weft group knitting fabric is Applying a primer resin to the surface of a concrete structure using a bi-directional composite fiber sheet in which the fineness of the knitted fabric and the wrinkle spacing of the fiber groups are different from the other knitted ground, and the composite fiber sheet a step of attaching to the surface of the ridge spacing is narrow that are arranged hand knitted surface concrete structure of the yarn, a top coat resin to the knitted fabric surface of the other side that ridges spacing yarn is widely arranged application of Characterized by comprising a step of impregnating .
Further, the present invention provides a concrete structure in which an undercoat resin applied to the surface of a concrete structure and a composite fiber sheet attached to the undercoat resin are laminated and the composite fiber sheet is impregnated with an overcoat resin. A structure for reinforcing an object, wherein a plurality of warp group knitted fabrics in which a plurality of warp yarns are arranged in parallel with a gap between them and a plurality of weft group knitted fabrics in which a plurality of weft yarns are arranged in parallel with a gap between them. The knitting yarns of the warp group and the weft group knitted fabric have one of the warp group knitted fabric and the weft group knitted fabric, the fineness of the knitted fabric and the spacing of the fiber groups with respect to the other knitted ground. two different directions of using composite fiber sheet, hand knitted fabric surface of the ridge spacing that is narrower array of yarns of said composite fiber sheet are attached via the undercoating resin to the surface of the concrete structure , the other side that the ridge spacing of the thread has not been widely array The topcoat resin knitted fabric surface, characterized in that it is impregnated.
In another embodiment of the present invention, the total yarn amount of either the warp group knitted fabric or the weft group knitted fabric in which the fineness is small and the yarn wrinkle spacing is narrow, the fineness is large, and The total yarn amount of either the warp group knitted fabric or the weft group knitted fabric in which the yarn wrinkles are widely arranged is in the same relationship.
In another embodiment of the present invention, the warp group weft fabric and the weft group knitted fabric constituting the composite fiber sheet are made of aramid fibers, and the proof stresses in the warp direction and the weft direction are 150 kN / m or more, respectively.
In another form of the present invention, the basis weight of the combined warp group knitted fabric and and weft group knitted fabric constituting the composite fiber sheet is 300~1300g / m ^2.

<1.6> Examples of Fiber Sheet Materials As fibers used in the composite fiber sheet 10, in addition to organic fibers such as aramid fibers, carbon fibers, glass fibers, and the like, various conventionally known chemical fibers can be used. These can be used alone or in combination of two or more.
The yield strength of the composite fiber sheet 10 is preferably in the range of 150 to 900 kN / m in both the warp direction and the weft direction.
If the proof stress is below the range, the reinforcing effect is small. Conversely, if the proof stress exceeds the range, the sheet weight (fiber amount) is too large, and it becomes difficult to impregnate the resin.
The yield strength of the composite fiber sheet 10 is preferably 250 to 700 kN / m, and more preferably 350 to 600 kN / m, within the above range.
Also, the basis weight of the combined warp group knitted fabric and weft group knitted fabric constituting the composite fiber sheet 10 is preferably from 300~1300g / m ^2, more preferably 450~1100g / m ^2, more preferably 550 to 900 g / m ² .
The basis weight in the present invention is measured in accordance with the method described in “6.4 Mass per unit area” of JIS L 1096 “General Textile Testing Method” and is expressed in absolute dry weight per unit area. It is.

Claims (6)

A method of reinforcing a concrete structure in which a fiber sheet is attached to the surface of the concrete structure to reinforce,
The warp group knitted fabric in which a plurality of warp yarns are arranged in parallel at intervals and the weft group knitted fabric in which the plurality of weft yarns are arranged in parallel at intervals are integrally bound by a plurality of knitting yarns. And using a bi-directional composite fiber sheet in which the warp spacing of at least the fiber groups of the warp group knitted fabric and the weft group knitted fabric is different,
Applying a primer resin to the surface of the concrete structure;
A step of sticking one of the warp group knitted fabric or the weft group knitted fabric in which the yarn spacing is arranged narrowly to the surface of the concrete structure;
Characterized in that it comprises a step of applying and impregnating a top coat resin to the other knitted fabric of the warp group knitted fabric or the weft group knitted fabric in which the yarn wrinkles are widely arranged,
A method of reinforcing concrete structures.   The method for reinforcing a concrete structure according to claim 1, characterized in that bi-directional composite fiber sheets having different finenesses of the warp group knitted fabric and the weft group knitted fabric and the wrinkle intervals of the fiber groups are used.   The total yarn amount of either the warp group knitted fabric or the weft group knitted fabric in which the fineness is small and the yarn spacing is narrow, the fineness is large, and the yarn spacing is wide. 3. The method for reinforcing a concrete structure according to claim 2, wherein the total yarn amount of the other knitted fabric of the warp group knitted fabric or the weft group knitted fabric is equal.   The warp group knitted fabric and the weft group knitted fabric constituting the composite fiber sheet are made of aramid fibers, and the proof stresses in the warp direction and the weft direction are 150 kN / m or more, respectively. The method for reinforcing a concrete structure according to any one of the above. The basis weight of the warp group knitted fabric and the weft group knitted fabric constituting the composite fiber sheet is 300 to 1300 g / m ^2. The concrete structure according to any one of claims 1 to 4, Reinforcement method. A reinforcing structure of a concrete structure in which an undercoat resin applied to the surface of a concrete structure and a composite fiber sheet affixed to the undercoat resin are laminated and the composite fiber sheet is impregnated with an overcoat resin. There,
The warp group knitted fabric in which a plurality of warp yarns are arranged in parallel at intervals and the weft group knitted fabric in which the plurality of weft yarns are arranged in parallel at intervals are integrally bound by a plurality of knitting yarns. And using a bi-directional composite fiber sheet in which the warp spacing of the fiber groups of the warp group knitted fabric and the weft group knitted fabric is different,
The other knitted fabric of the warp group knitted fabric or the weft group knitted fabric in which the yarn heel intervals are arranged narrowly is attached to the surface of the concrete structure via the primer resin,
The overcoat resin is impregnated in any one of the warp group knitted fabric and the weft group knitted fabric in which the yarn spacing is widely arranged,
Reinforcement structure for concrete structures.

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