JP2003080606A - Reinforcing material for concrete structure and method for reinforcing concrete structure using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcing material for a concrete structure having good reinforcing properties with respect to the concrete structure, not generating the peeling of a sheet or the drooling of a resin composition and excellent in execution efficiency, and a method for reinforcing the concrete structure using the same. SOLUTION: The reinforcing material for the concrete structure contains a sheet comprising vinylon fibers and the normal temperature curable resin composition and the thixotropy indexes TI0 and TI30 at the time of preparation of the resin composition and after the elapse of 30 min from the preparing time of the resin composition and the viscosity η0 (mPa.S) at the time of preparation of the resin composition satisfy formula (1): TI0 >=3.0+0.5T, formula (2) TI30 >=TI0 -1.0 and formula (3) 5,500+500T<=η0 <=4(5,500+500T) with respect to the thickness T (mm) of the sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing material for reinforcing the surface of a concrete structure to prevent concrete pieces from falling off from the surface, and a reinforcing material for a concrete structure using the reinforcing material. With respect to the method.

[0002]

2. Description of the Related Art Conventionally, in order to reinforce the surface of a concrete structure such as an inner wall surface of a tunnel or the like, an outer wall surface of a slab of a road bridge, a beam, a bridge pier or the like, a fiber reinforced plastic (FRP) is used for the surface. A method of providing a coating layer is often used. Specifically, a reinforcing fiber sheet such as vinylon fiber is impregnated with an impregnating resin (for example, an epoxy resin) that hardens to form an FRP and that acts as an adhesive to a concrete structure, and then this is used for concrete. The surface of a concrete structure is reinforced by being attached and fixed to the surface of the structure.

Here, in order to impart sufficient strength as the fiber reinforced plastic (FRP) to the reinforcing fiber sheet, the resin to be impregnated is applied to the reinforcing fiber sheet in a thickness not less than the thickness of the reinforcing fiber sheet. Need to be completely covered. Therefore, conventionally, a low-viscosity epoxy resin has been often used as the impregnating resin in order to improve the impregnation property into the reinforcing fiber sheet. However, when the viscosity of the resin is low or when the thixotropy of the resin is poor, it takes a long time for the resin to harden after the application work is completed.
There is a problem that the reinforcing fiber sheet is peeled off to form a gap between the reinforcing fiber sheet and the surface of the concrete structure, the reinforcing fiber sheet is entirely dropped from the concrete structure, or the impregnating resin is dripping. In addition, when a reinforcing fiber sheet having a large thickness is attached, if the viscosity of the impregnating resin is low, an adhesive force based on the viscosity of the resin cannot be sufficiently obtained, and therefore an adhesive force that can withstand the weight of the sheet is obtained. Disappear.
As a result, the sheet has to be divided into several layers and attached in advance, which causes a problem that work efficiency is significantly reduced.

On the other hand, if the viscosity or thixotropy of the impregnating resin is too high, there arises a problem that it takes a long time to impregnate the reinforcing fiber sheet with the resin, or the impregnation itself becomes extremely difficult. Further, along with this, there is a problem that the handleability of the reinforcing fiber sheet and the workability of sticking are deteriorated. Therefore, the effect of reinforcing the surface of the concrete structure should be sufficient,
In order to obtain stable adhesiveness (adhesion stability) of the reinforcing fiber sheet for a long period of time, it is extremely important to adjust the balance between the viscosity of the impregnating resin and thixotropic property (thixotropic property). The current situation is that the points have not been thoroughly examined.

[0005]

[Patent Document 1] Japanese Patent Application Laid-Open No. 7-52267
The publication discloses a resin composition for sticking and fixing a reinforcing fiber sheet, which has thixotropy. However, like the resin composition disclosed in the above publication, the viscosity is 10 to 50 P (Poise, 1000 to 5).
000 mPa · s (see claim 3 of the same gazette) and a large rocking degree of 4 to 9 (see claims 3 and 4 of the gazette) for reinforcement to a concrete structure. Stable adhesiveness cannot be obtained when the fiber sheet is attached.

[0006] Incidentally, the "rocking degree" (JI
4.5) of SK 6901 "Test method for liquid unsaturated polyester resin" is a value measured by the following procedure. First, the sample temperature is set to 25 ± 0.5 ° C., two stirring rods are held in hands, and the whole is stirred at about 4 revolutions per second for about 10 seconds. Then, the rotor and the guard are put and left still for 5 minutes. Next, the rotor is rotated at 60 rpm, and the index when the rotor is rotated for 3 minutes is read. Further, after standing still for 5 minutes, the number of rotations of the roller is set to 6 rotations per minute, and the index at the time of rotation for 3 minutes is read. The thus obtained viscosity when measured at 6 revolutions per minute is divided by the viscosity when measured at 60 revolutions per minute to obtain the thixotropic degree.

Further, in Japanese Patent Laid-Open No. 11-00633, a thixotropic index is 3.0 or more and a viscosity is 1 to 30.
A method of repairing / reinforcing a concrete structure using a reinforcing fiber sheet impregnated with a two-pack type epoxy resin of P (100 to 3000 mPa · s) is disclosed. However, the thixotropic properties of the above-mentioned resin have been considered, but the viscosity of the resin itself is as low as 1 to 30 P, so that the adhesive stability of the reinforcing fiber sheet after sticking is still poor. There is.

The "thixotropic index" in the above publication is a value measured by the following procedure. First,
JIS Z 8803, "Viscosity of liquid-Measuring method", 9.
The viscosity of the sample is measured when the sample is rotated 5 minutes per minute in an atmosphere of 20 ° C. in accordance with the “cone-plate viscometer method for measuring viscosity” using an E-type viscometer. Further, the viscosity of the sample was measured when it was rotated at 0.5 rpm under an atmosphere of 20 ° C., and the measured value (0.5 rpm) was calculated as
The thixotropy index is obtained by dividing by the measurement value obtained when the above-mentioned 5 revolutions per minute are performed.

Therefore, an object of the present invention is to provide good reinforcement to a concrete structure, to prevent peeling of the reinforcing fiber sheet after construction, and to cause sagging of the impregnating resin composition during construction. It is to provide a reinforcing material for a concrete structure which is excellent in construction efficiency. Another object of the present invention is to provide a reinforcing method using such a reinforcing material for a concrete structure.

[0010]

MEANS FOR SOLVING THE PROBLEMS AND EFFECTS OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that (i) thixotropic properties of a resin composition to be impregnated into a reinforcing fiber sheet. While setting the viscosity and the thickness according to the thickness of the sheet, (ii) not only prescribing the degree of thixotropy at the time of preparation of the resin composition, but also about the degree of thixotropy at a predetermined time after the preparation. By also specifying, the reinforcing material for concrete structures, which is excellent in impregnation into the reinforcing fiber sheet, adhesion stability with the surface of the concrete structure, workability during sticking, etc., and therefore excellent in construction efficiency The present invention has been completed by finding a completely new fact that it can be obtained.

That is, the reinforcing material for a concrete structure according to the present invention comprises a sheet made of vinylon fiber and a room temperature curable resin composition to be impregnated into the sheet, and the resin composition is prepared. a thixotropic index TI ₃₀ in 30 minutes after the time of thixotropic index TI ₀ and preparation, the thickness of the sheet T and (mm), but each formula (1) and (2) at the time:

[0012]

[Equation 4]

And the viscosity η ₀ (mPa · s) at the time of preparing the resin composition and the thickness T of the sheet.
(Mm) is the formula (3):

[0014]

[Equation 5]

It is characterized in that it satisfies the above. Further, the method for reinforcing a concrete structure according to the present invention is a method using a sheet made of vinylon fiber impregnated with a resin composition, wherein the thixotropy index TI _{0 at} the time of preparation and the time after 30 minutes from the time of preparation The thixotropy index TI ₃₀ and the viscosity η ₀ (mPa · s) at the time of preparation and the thickness T (mm) of the sheet are represented by the following formulas (1) to (3):

[0016]

[Equation 6]

A room temperature curable resin composition satisfying the above relationship is impregnated into a sheet made of vinylon fiber, and then the sheet is attached to the surface of a concrete structure. In the method of reinforcing a concrete structure, on the surface of the concrete structure, a primer layer made of a resin of the same type as that used in the resin composition or a resin having compatibility is previously formed, and the primer layer It is preferable to attach the sheet to the surface, preferably after the primer layer is cured, from the viewpoint of further improving the adhesion stability between the concrete structure and the sheet.

In the reinforcing material for a concrete structure and the method for reinforcing a concrete structure using the same according to the present invention, TI ₀ showing thixotropic property (thixotropic property) when the resin composition is prepared, and 30 from the preparation. By setting the TI ₃₀ showing thixotropy after a lapse of minutes and the viscosity η ₀ at the time of preparation in the above range, the resin composition of the above resin composition to a sheet (reinforcing fiber sheet) made of vinylon fibers was set. It is possible to achieve both good impregnation properties, appropriate curability of the resin composition, and good handleability during the pasting work.

Specifically, since the resin composition used in the present invention is set to have a low viscosity when a large shear stress is applied, such as during impregnation work, the resin composition for reinforcing fiber sheet is The resin can be impregnated quickly. On the other hand, the viscosity is set to be high when almost no shear stress is applied, such as after the completion of the impregnation work, and moreover, thixotropy after the lapse of a predetermined time from the preparation of the resin composition is not too low. Since it is set, it is possible to sufficiently prevent the reinforcing fiber sheet from peeling off or falling off from the surface of the concrete structure. In addition, since the resin composition with which the reinforcing fiber sheet is impregnated has the thixotropic property as described above, it is possible to adjust the curing speed to a speed suitable for sticking work.

As a result of the above, according to the present invention, the conventional reinforcing fiber sheet is peeled off after application to form a gap with the surface of the concrete structure or is dropped from the surface. The problem can be solved, and a stable adhesion state between the reinforcing fiber sheet and the concrete surface can be realized. Moreover, sagging of the resin composition does not occur at the time of attaching the reinforcing fiber sheet. Also,
Since the thixotropy and viscosity of the resin composition are set according to the thickness of the reinforcing fiber sheet, a thin reinforcing fiber sheet is laminated even when a thick reinforcing fiber sheet is attached. It is not necessary to repeat the pasting work in several times. More specifically, the thickness of the sheet is 1 mm
It is also possible to easily attach a reinforcing fiber sheet having a very high reinforcing efficiency that exceeds the above. Therefore, workability at the time of attaching the reinforcing fiber sheet is good, and an excellent reinforcing effect and high construction efficiency can be realized.

Further, in the present invention, since the vinylon fiber (polyvinyl alcohol synthetic fiber) having high strength is used as the fiber constituting the reinforcing fiber sheet, the reinforcing effect of the concrete structure is further enhanced. can do. Therefore, the reinforcing material for a concrete structure and the method for reinforcing a concrete structure using the same according to the present invention are applicable to the surface of a concrete structure, that is, an inner wall surface of a tunnel or the like, a floor slab of a road bridge, a beam, a pier or the like. It is suitable as a member for reinforcing the outer wall surface (in particular, the outer wall surface on the lower surface side where the peeling of the reinforcing fiber sheet easily occurs, the rising wall surface, the back surface of the floor slab, etc.) and the method for reinforcing the concrete structure. It should be noted that the improvement of workability of sticking and the improvement of construction efficiency will greatly contribute to the reduction of construction cost in the construction of infrastructure such as tunnels and piers.

In the present invention, the thixotropy index (TI) of the resin composition is an index for its thixotropy. TI in the present invention
Is a viscosity measured with an E-type viscometer (JIS Z8803-9 mentioned above; measurement condition: 3 degree cone, 20 ° C.), and the viscosity when the rotation speed of the resin composition is 1 rpm is 10 rpm. It is the value divided by the viscosity. When this TI value is large, it indicates that there is a large difference in the viscosity of the resin composition between when a large shearing force is applied and when only a small shearing force is applied, that is, thixotropy of the resin composition It is high.

In the present invention, the term "at the time of preparation" of the resin composition means that the base resin is impregnated with other components such as a thickener, a thixotropic agent, a curing agent, a solvent and a diluent. (Immediately after) when the resin composition for use was prepared. In the following description, the value of the thixotropy index at the time of preparation (immediately after the preparation) of the resin composition is represented by "TI ₀ ", and the thixotropy index after 30 minutes from the preparation of the resin composition is shown as "TI value. ₃₀ ".

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a reinforcing material for a concrete structure according to the present invention and a method for reinforcing a concrete structure using the same will be described in detail. Examples of the concrete structure which is a target of the reinforcing material and the reinforcing method according to the present invention include an inner wall surface of an underground structure such as a tunnel and an outer wall surface of a floor slab of a road bridge, a beam, a pier and the like.

[Reinforcing Fiber Sheet] In the present invention, a vinylon fiber sheet is used as the reinforcing fiber sheet attached to the surface of the concrete structure. Vinylon fiber is a general term for polyvinyl alcohol-based synthetic fibers, and a non-woven fabric or woven fabric of such fibers exhibits extremely high strength, and is therefore suitable as a reinforcing fiber sheet.

[Resin Composition] In the present invention, as the resin composition to be impregnated into the reinforcing fiber sheet made of vinylon fiber, one having a base material of a room temperature curable resin is used.
Examples of the room temperature curable resin include epoxy resin, vinyl ester resin, methacrylic resin, polyester resin, urethane resin and acrylic resin. Among them, it is more preferable to use an epoxy resin in order to further improve the impregnating ability to the reinforcing fiber sheet and the adhesiveness to the concrete surface, and to prevent peeling of the reinforcing fiber sheet, a resin composition of It is more preferable to use a methacrylic resin such as methyl methacrylate (MMA) in order to realize rapid curing.

The resin composition is prepared by using the above-mentioned room temperature curable resin as a base resin and mixing it with other components such as a thickener, a thixotropic agent, a curing agent, a solvent and a diluent. It Examples of the thickener include inorganic thickeners such as finely divided silica, bentonite, and clay; organic thickeners such as amide wax, polyethylene wax, and polycarboxylic acid salts, and various conventionally known thickeners. To be

The thixotropic agent is, for example,
Tokuyama's finely divided silica "Reorosil QS-10"
2 ”and the like. Examples of the curing agent include isophoronediamine, metaxylylamine, and polyamidoamine. Examples of the solvent / diluent include conventionally known organic solvents that can dissolve the room temperature curable resin used.

In addition to the above components, a colorant, an adhesive such as a silane coupling agent, an additive commonly used in paints, and the like can be appropriately added. The amount of other components such as the above-mentioned thickener, thixotropic agent, curing agent, solvent, and diluent is not particularly limited, and is appropriately set according to the thixotropic degree and viscosity of the resin composition. do it. The resin composition is a base material prepared by premixing the above-mentioned base resin with the above-mentioned thickener, thixotropic agent, solvent, diluent and the like, and the curing agent, which is stored separately, and has a concrete structure. They are used as a mixture just before the reinforcement work of the product.

[Thixotropic Property of Resin Composition] In the present invention,
The thixotropic property of the resin composition impregnated into the reinforcing fiber sheet is
According to the thickness T of the sheet (unit: mm), the above formula
It is set to satisfy (1) and equation (2). Thixotropic index T when preparing a resin composition
It is preferable that I ₀ satisfies the formula (1 ′): TI ₀ ≧ 3.5 + 0.5T (1 ′) in the range of the formula (1), and the formula (1 ″): TI ₀ It is more preferable to satisfy ≧ 3.8 + 0.5T (1 ″). In addition, it is preferable to increase the value of TI ₀ as the viscosity η ₀ at the time of preparing the resin composition described later is higher.

When TI ₀ is outside the range of the above formula (1), that is, with respect to the thickness T (mm) of the reinforcing fiber sheet, 3.
When it is less than 0 + 0.5T, thixotropy of the resin composition is poor and stable adhesiveness to the reinforcing fiber sheet cannot be realized. On the other hand, the upper limit of TI ₀ is not particularly limited in the present invention, and generally a larger value is preferable. The thixotropy index TI ₃₀ after 30 minutes from the time of preparation of the resin composition is represented by the above formula (2).
In particular, it is preferable to satisfy the formula (2 ′): TI ₃₀ ≧ TI ₀ −0.7 (2 ′), and the formula (2 ″): TI ₃₀ ≧ TI ₀ −0.5. It is more preferable to satisfy (2 '').

When TI ₃₀ is out of the range of the above formula (2), that is, the thixotropic index T at the time of preparation.
When the _value becomes smaller than I ₀ by 1.0 or more and the degree of thixotropy disappearing with the lapse of time becomes large, the reinforcing fiber sheet is liable to be peeled or dropped during the process of curing the resin composition. On the other hand, the upper limit of TI ₀ is not particularly limited in the present invention, and generally a larger value is preferable. If the viscosity η ₀ during the preparation of the resin composition is less than the range of the above formula (3), the viscosity of the resin composition will be too low, so that the resin composition is cured even if TI ₀ or TI ₃₀ is large. In the process, the reinforcing fiber sheet is likely to peel or fall off. On the other hand, when η ₀ exceeds the range of the above formula (3), the viscosity of the resin composition becomes too high, so that even if TI ₀ or TI ₃₀ is large, the impregnating property into the reinforcing fiber sheet is low, Impregnation cannot be achieved.

[Concrete Structure Reinforcing Method] As described above, the concrete structure reinforcing method according to the present invention uses a sheet made of vinylon fibers impregnated with a resin composition (reinforcing fiber sheet) as a concrete structure. Of the resin composition, wherein the thixotropic property and viscosity of the resin composition and the thickness of the sheet satisfy the above formulas (1) to (3). One embodiment of the above-mentioned reinforcing method is shown below.

First, an adhesion-inhibiting substance such as laitance is removed from the surface of the concrete layer that defines the underground space by treatment with a sander, and a primer layer is applied and formed on this surface. The resin forming the primer layer is not particularly limited, but it is preferable to use the same resin as the resin with which the reinforcing fiber sheet is impregnated, or a resin having good compatibility or adhesiveness. The unevenness generated on the surface of the primer layer may be corrected with putty or the like, if necessary. The resin used as the putty is not particularly limited, but it is preferable to use the same resin as the resin with which the reinforcing fiber sheet is impregnated or a resin having good compatibility or adhesiveness.

Then, the resin composition to be impregnated into the reinforcing fiber sheet is applied to the surface of the primer layer (and putty) using a roller or the like, and then the reinforcing fiber sheet is quickly attached. Further, subsequently, the resin composition is applied to the attached reinforcing fiber sheet, the entire sheet is completely covered with the resin composition, and then the resin composition is cured. Thereby, the reinforcing fiber sheet can be made to act as a fiber reinforced plastic (FRP), and an extremely excellent reinforcing effect can be exerted in a state of being firmly adhered to the surface of the concrete structure.

The reinforcing fiber sheet is required to be continuously attached to the surface of the concrete structure without any gap. If the reinforcing fiber sheet is formed discontinuously, a sufficient reinforcing effect cannot be obtained. In order to continuously form the reinforcing fiber sheets, it is necessary to attach the reinforcing fiber sheets without any gaps, and at the joint portion of the reinforcing fiber sheets, the reinforcing fiber sheets that are laid next to each other are slightly overlapped with each other. It is preferable to bond the overlapped portions with the resin composition.

[0037]

EXAMPLES The present invention will be described with reference to Examples and Comparative Examples. Example 1 A reinforcing fiber sheet made of vinylon fiber was attached to the lower surface of a concrete structure (2 m square) having a thickness of 15 cm by the following procedure. First, the surface of the concrete structure was treated with a sander to remove adhesion-inhibiting substances such as laitance. Then, 200 to 250 g of an epoxy resin (trade name "Grip Coat GB30" manufactured by Sumitomo Rubber Industries, Ltd.) was applied to the lower surface of the concrete structure from which the leitance and the like had been removed in an amount of 200 to 250 g per 1 m ² and cured. After forming the primer layer in this way, putty made of epoxy resin [trade name "Grip Bond G" manufactured by Sumitomo Rubber Industries, Ltd.
B25 "] was used to repair the unevenness of the concrete surface. After the putty was cured, the impregnating resin composition was applied on the surface of the primer layer in an amount of 500 g per 1 m ² .

Here, the resin composition for impregnation includes Sumitomo Rubber
Product name "Gripbond GB35s" manufactured by Kogyo Co., Ltd.
[Bisphenol A type liquid epoxy resin (Japan
Product name "Epicote 828" manufactured by Poxy Resin Co., Ltd.
Finely divided silica as a thickener (trade name of Tokuyama Corp.)
"Roleoseal QS-102")
And a modified polyamine-based curing agent (isophorone diamine
That consists of) and). Resin composition for impregnation
For thixotropy of substances, adjust the blending amount of finely divided silica.
The thixotropic index TI₀
(At the time of preparation) is 3.5, TI ₃₀(After 30 minutes) is 3.
1. Viscosity η during preparation of resin composition₀Is 6000m
It was adjusted to be Pa · s.

After applying the resin composition for impregnation, a sheet (reinforcing fiber sheet) made of vinylon fiber [Vinylon continuous fiber manufactured by Kuraray Co., Ltd., trade name "Kuraray Vinylon VK0707"] was quickly attached to the surface of the resin composition. . The reinforcing fiber sheet had a thickness T of 1.0 mm. Continuing,
The resin composition for impregnation was applied 500 per 1 m ^{2 of the} sheet.
g and impregnated, and the entire sheet was completely covered with the resin composition. Furthermore, by allowing this to stand for one day to completely cure the resin composition, a layer (FRP layer) composed of the vinylon fiber sheet and the resin composition was formed on the lower surface of the concrete structure. After the formation of the FRP layer, a hammering test was conducted to confirm the concrete surface and the FR.
As a result of checking whether or not a void is present between the P layer and the P layer, it was found that the void was not observed and the FRP layer and the concrete structure were completely adhered and integrated.

Comparative Example 1 As an impregnating resin composition, 2 parts by weight of a thickener (“Leoroseal QS-102” described above) and calcium carbonate were added to 100 parts by weight of an epoxy resin (“Epicoat 828” described above). 20 parts by weight of the main agent added and the modified polyamine-based curing agent (isophoronediamine) are mixed,
TI ₀ is 2.4, TI ₃₀ is 1.9, η ₀ is 6000 mP
A reinforcing fiber sheet (a vinylon continuous fiber “Kuraray vinylon VH0707” described above) is attached to the lower surface of the concrete structure in the same manner as in Example 1 except that the one adjusted to have a · s is used. I worked. As a result, it was found that the reinforcing fiber sheet was peeled off during the impregnation operation of the resin composition, and it could not be put to practical use.

Comparative Example 2 As a resin composition for impregnation, an epoxy resin (“Epicote 828” described above) and fine silica (“Reoroseal QS-102” described above) were mixed, and the modified polyamine-based resin was used. And a curing agent (isophoronediamine). Regarding thixotropy and the like of the resin composition for impregnation, TI ₀ is 3.5, TI ₃₀ is 2.0, and viscosity η ₀ is 40 by adjusting the blending amount of finely divided silica.
It was adjusted to be 00 mPa · s.

A reinforcing fiber sheet (the above-mentioned vinylon continuous fiber "Kuraray vinylon VH0707") was attached to the lower surface of the concrete structure in the same manner as in Example 1 except that the resin composition for impregnation was used. , FRP layer was formed. In Comparative Example 2, the impregnation of the resin composition into the reinforcing fiber sheet could be smoothly progressed at the initial stage of the work. However, by curing the resin composition, FR
After obtaining the P layer, when the degree of integration was observed by a hammering test, it was found that about 3 was found between the FRP layer and the concrete surface.
It was found that voids were generated in the area of 0%. Therefore, it was not possible to realize complete integration of the FRP layer and the concrete structure.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // E01D 19/02 E01D 19/12 4L048 19/12 D06M 101: 24 D06M 101: 24 B29C 67/14 X F term (reference) 2D055 CA03 KB11 KB15 KB16 2D059 AA03 AA14 BB37 BB39 GG02 GG23 GG40 2E164 AA05 AA11 4F205 AA36 AD16 HA19 HA29 HA45 HC12 HK17 4L033 AA05 AB05 AC11 AC15 CA18 CA45 CA49 CA18 AB0748007

Claims (3)

[Claims] 1. A reinforcing material for a concrete structure, comprising a sheet made of vinylon fiber and a room temperature curable resin composition to be impregnated into the sheet, the thixotropy index TI ₀ at the time of preparing the resin composition. And the thixotropy index TI ₃₀ after 30 minutes from the time of preparation and the thickness T (mm) of the sheet are expressed by the formulas (1) and (2): And the viscosity at the time of preparing the resin composition η ₀ (mPa ·
s) and the thickness T (mm) of the sheet are expressed by equation (3): Reinforcing material for concrete structures that satisfies the requirements. 2. A method for reinforcing a concrete structure using a sheet made of vinylon fibers impregnated with a resin composition, comprising a thixotropic index TI ₀ at the time of preparation,
Thixotropic index TI ₃₀ after 30 minutes from the time of preparation and viscosity η ₀ (mPa · s) at the time of preparation
Between the thickness T (mm) of the sheet and the following formula (1)
(3): [Equation 3] A method for reinforcing a concrete structure, comprising impregnating a sheet made of vinylon fiber with a room-temperature-curable resin composition satisfying the above relationship, and attaching the sheet to the surface of the concrete structure. 3. A primer layer made of a resin of the same type as that used in the resin composition or a resin having compatibility is previously formed on the surface of the concrete structure, and the sheet is attached to the surface of the primer layer. Claim 2
A method for reinforcing a concrete structure as described.