JP2001159213A - Reinforcing panel for concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcing panel for concrete structure capable of ensuring desired structural strength, preventing the occurrence of rust and peeling and holding satisfactory quality even after construction and having excellent construction property. SOLUTION: A carbon fiber sheet C is provided between flexible boards F and is integrally formed by adhesive B to constitute a reinforcing panel P for concrete structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing panel for reinforcing a concrete structure.

[0002]

2. Description of the Related Art Concrete structures are made of various materials and materials.
Due to structural factors, aging occurs, cracks occur and the internal rebar corrodes, cross-sectional defects occur, etc., and the structural strength is reduced, so it is necessary to reinforce as necessary.

Conventionally, existing concrete structures (hereinafter, referred to as “concrete structures”)
As a method of reinforcing "existing concrete", a steel plate winding method, a carbon fiber sheet winding method, a concrete thickening method, and the like have been implemented, and each has the following problems.

[0004]

The steel sheet winding method is a method in which a steel sheet having a thickness of 6 mm to 15 mm is installed outside the existing concrete and a gap between the existing concrete and the steel sheet (10 mm to 10 mm).
30 mm) cement-based high-strength non-shrink mortar
This method is called “high-strength non-shrink mortar”. However, in this steel sheet winding method, since the specific gravity of the steel sheet is as heavy as 7.85, workability is poor, and a large heavy machine is required for construction. In addition, since the steel sheet rusts, rust prevention measures are required, and maintenance has to be performed in about five years. In addition, there is a problem that welding of the steel sheet to the steel sheet requires measures against fire, and the quality after construction depends on the skill of a welder, and there is a concern that the quality may vary.

[0005] In addition, the carbon fiber sheet winding method is a method in which the surface of existing concrete is scraped to form a smooth surface.
This is a method of attaching a carbon fiber sheet with epoxy resin.
However, in the carbon fiber sheet winding method, since the carbon fiber sheet may be peeled off after construction unless the surface of the existing concrete is carefully removed, that is, so-called groundwork treatment, peeling is performed after construction by the skill of the sticking work. There was a problem that the danger was great.

[0006] The concrete thickening method is to scrape the surface of the existing concrete and form it smoothly,
In this method, a formwork is installed on the surface of existing concrete, a reinforcing bar is placed in the gap (15 cm to 30 cm) between the existing concrete and the formwork, and concrete is cast and integrated.
However, in this concrete thickening method, since a concrete having a thickness of 15 cm to 30 cm is cast outside the existing concrete, the structure becomes heavy. For example, when reinforcing a cement silo, the reinforcement of the foundation is necessary. Had the problem that Furthermore, since the thickness of the thickened concrete is 15 cm to 30 cm, a temperature stress occurs due to the heat of hydration of the cement between the concrete and the existing concrete, and after construction, the risk of cracks occurring in the thickened concrete increases. There was also a problem that.

[0007] In recent years, due to the deterioration of concrete over time, there have been many accidents in which the cold joint portion of the secondary lining concrete of the tunnel falls off and falls. Therefore, in addition to the above-mentioned construction method, a construction method in which an L-shaped steel material is installed by bolts in a direction perpendicular to the cold joint to prevent peeling of the cold joint portion is used as an emergency measure. However, since the above-mentioned construction method only provides an emergency reinforcement, it is predicted that the cold joint cannot be supported on the surface and that the L-shaped steel material is expected to rust. Had the problem that

The present invention has been made in order to solve the above-mentioned problems, and it is possible to secure a desired structural strength, and it is free from rusting, peeling, etc. An object of the present invention is to provide a reinforcing panel of a concrete structure (hereinafter, referred to as a “reinforcing panel”) that can maintain quality and is excellent in workability.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a panel used for reinforcing a concrete structure, wherein a carbon fiber sheet is interposed between flexible boards and integrally formed with an adhesive. . Here, the flexible board is preferably a high-strength flexible board.

Therefore, according to the present invention, the carbon fiber sheet is interposed between the flexible boards to form a reinforcing panel integrally formed with an adhesive. Structural strength can be obtained. In addition, since the reinforcing panel can be manufactured in a factory in advance, the reinforcing panel can have uniform quality. In addition, since it can be installed simply by joining it to the surface of existing concrete thinly, it has quick and easy workability,
Since there is no need to perform welding work of the iron plate or sticking work of the carbon fiber sheet, there is no variation in quality due to the skill of the worker, and stable quality can be secured. Furthermore, since it does not rust or peel off, the quality after construction can be maintained well.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a reinforcing panel of a concrete structure according to the present invention. In the following description, the same components will be denoted by the same reference symbols, without redundant description. Further, in the following description, numerical values related to each component may be described for reference, but it goes without saying that the present invention is not limited to the numerical values.

(1) Structure of Reinforcement Panel P A reinforcement panel P shown in FIG. 1 is obtained by interposing a carbon fiber sheet C between two high-strength flexible boards F and integrally molding with an adhesive B. It is.

[Carbon fiber sheet C] The carbon fiber sheet is impregnated with an epoxy resin and has a specific gravity of 1.7 to 1.8.
And the cured product has the property of not rusting, and in the fiber direction, is about 5 to 6 times that of a reinforcing bar.
It has a large tensile strength of 0 (N / mm ² ).
Therefore, by interposing the carbon fiber sheet C between the high-strength flexible boards F, it is possible to obtain a structural strength equal to or higher than that of reinforced concrete with a thin film. As the carbon fiber sheet C, a known single orientation sheet, a single orientation sheet alternately laminated like a plywood, a cross-shaped sheet, or the like can be used.

[High strength flexible board F] High strength flexible board F is made of cement, calcium silicate,
Organic fibers (pulp) are the main component, and after kneading, they are formed into rolls and dewatered and pressed. As the high-strength flexible board F, a well-known product can be used.
It is a product of a standard of ~ 6 mm. The reason for using the high-strength flexible board F is that it can be easily manufactured in a factory, the product quality is stable, and the bending strength is 30 (N
/ Mm ² ) or more, no cracks are generated on the surface, and bending can be easily performed. Therefore, it can be formed into a desired shape according to the shape of the existing concrete to be reinforced, and has nonflammability. That the specific gravity is 1.6 ~
The lightness of 1.8 means that workability and transportation are easy.

[Adhesive B] The adhesive B is used to firmly join the high-strength flexible board F and the carbon fiber sheet C,
Any type of material may be used as long as it can be integrally molded, but epoxy resin is preferred from the viewpoint of adhesive strength and workability. Other adhesives B include resin adhesives such as vinyl acetate resin, EVA (ethylene-vinyl acetate copolymer resin) and acrylic resin, and rubbers such as chloroprene rubber and styrene / butadiene rubber. It is also possible to use a water-based or air-hardened adhesive such as a cement-based adhesive or a gypsum-based adhesive.

[Reinforcing Panel P] The reinforcing panel P is formed by sandwiching a carbon fiber sheet C in a sandwich shape between two high-strength flexible boards F and interposing an adhesive B to form a high-strength flexible board F and carbon fiber The sheet C and the sheet C are integrally formed. The amount of the carbon fiber sheet C is determined based on the structural strength required for the existing concrete, and if necessary, a predetermined number of carbon fiber sheets C are used in an overlapping manner.
Further, when it is necessary to reinforce the stress acting in two directions, it can be dealt with by arranging the carbon fiber sheet C so that the directions of the fibers are two directions.

Further, the carbon fiber sheet C is interposed between the high-strength flexible boards F because the carbon fiber sheet C is peeled off when the carbon fiber sheet C is directly adhered to the surface of the existing concrete. This is for preventing the carbon fiber sheet C from being energized and preventing the carbon fiber sheet C from being deteriorated due to ultraviolet rays.

The specific gravity of the reinforcing panel P having the above structure is 1.6 to 1.6.
Since it is about 1.8 and its thickness is 7 mm to 15 mm, it can be formed to be extremely lightweight and high in strength (see Examples). Moreover, since it can be manufactured in a factory in advance, the quality is uniform and the weight is light, so that there is an excellent advantage that the handling is easy and the transportation cost is low.

(2) Method of Reinforcement of Existing Concrete 10 Using Reinforcement Panel P Next, the method of reinforcing the existing concrete 10 using the reinforcement panel P
The method of reinforcing the steel will be described. Since there are mainly the following three methods for joining the reinforcing panel P and the existing concrete 10, an appropriate method should be selected according to the degree of deterioration of the existing concrete 10 and the situation at the construction site. become.

[Joining Method] a) A joining method using the filler 21 (see FIG. 2 (a)).
The reinforcing panel P is installed at an interval of 15 mm, and the filler 2 is placed inside a gap between them (hereinafter, referred to as a “filling gap L”).
This is a joining method in which both are filled and the two are integrated.

The present method is used when the surface of the existing concrete 10 is not smooth, and has an advantage that the foundation treatment of the existing concrete 10 can be easily completed. Here, the filling gap L is 10 mm to 1 mm.
Most preferably, the range is 5 mm. The reason is that when the filling interval L is set to the above-mentioned interval, the interval can be made smaller than the thickness of the thickened concrete in the conventionally used concrete thickening method, and the material can be reduced, such as a tunnel. It is possible to secure the inner cross section, and it is economical because the work is short and the construction period can be shortened. Note that the filling gap L can be set to 10 mm or less, but in that case, the foundation treatment of the existing concrete 10 must be carefully performed. Also,
If a certain interval is not ensured, there is a great risk that a portion where the existing concrete 10 and the reinforcing panel P are not integrated may occur.

The quality of the filler 21 used in the present method needs to be such that the fluidity is good and no material separation occurs, no volume shrinkage occurs after filling, and an early strength can be obtained. When a high-strength non-shrink mortar is used as the filler 21 having such properties, as a result of tests using various materials and blends, it was found that ultra-high-strength cement, expandable
Mixed with high performance water reducing agent as main raw material, 4
Those having a strength of 0 (N / mm ² ) or more were optimal.

As the other filler 21, fillers such as epoxy resin, EVA, polymer resin, vinyl acetate resin, rubber latex, acrylic emulsion, recycled rubber and silicone can be used. Is possible. Among them, it is optimal to use an epoxy resin from the viewpoint of the adhesive strength between the existing concrete 10 and the high-strength flexible board F and workability, and in particular, those that can obtain the adhesive strength even on a wet surface are suitable. Also, the filling gap L
When is small, it is suitable to use a so-called high fluidity type in which the viscosity of the epoxy resin is reduced from the viewpoint of workability.

B) Joining method using adhesive 22 (FIG. 2)
(See (b).) This method is a joining method in which the adhesive 22 is applied to one side surface of the reinforcing panel P and the reinforcing panel P and the existing concrete 10 are integrated. This method uses existing concrete 1
This method is used in places where careful ground treatment of 0 is unnecessary. In particular, since it is not necessary to secure the filling gap L, it is suitable for construction in a place where it is necessary to secure an inner space section such as a tunnel. Further, as compared with the joining method using the filler 21, only by applying the adhesive 22 on the surface of the reinforcing panel P and joining, the reinforcing panel P is quickly and easily reinforced, and is excellent in that structural strength can be obtained. ing. The adhesive 22 used in the present method is optimally an epoxy resin in terms of adhesive strength and workability, but the epoxy resin as the adhesive 22 is
It is necessary to use a type having a high viscosity and a large initial strength without causing liquid dripping. Further, the epoxy resin needs to be applied to the entire area of one surface of the reinforcing panel P in order to secure the adhesiveness.

C) A joining method using both the filler 21 or the adhesive 22 and the anchor bolt 23 (see FIGS. 2 (c) and 2 (d)).
b) The bonding method using the adhesive 22 includes an anchor bolt 23
It is a method of combining. That is, a predetermined number of anchor bolts 23 are inserted from the surface side of the reinforcing panel P into the reinforcing panel P and the existing concrete 10 joined by the filler 21 or the adhesive 22, and integrated therewith. This method is used in a place where the existing concrete 10 needs to be firmly joined.

The anchor bolt 23 used in this method is made of a stainless steel material which does not rust because the reinforcing panel P has a feature of not rusting. Also, depending on the soundness of the existing concrete 10, the anchor bolts 23
Typically, 5mm to 12mm in diameter and 30mm to 1 in length
The one having a size of 50 mm is used. According to this method, the fixing panel P can be easily fixed by the anchor bolts 23, and a large structural strength can be obtained, which is very effective.

The reinforcing panel P and the existing concrete 1
Needless to say, the filler 21 and the adhesive 22 for integrating 0 are not limited to the materials described in the above embodiment.

[Details of Construction Method] Reinforced panel P of the present invention
The method of reinforcing the existing concrete 10 using the method is to determine the type, shape and location of the existing concrete 10 to be reinforced, the surface condition of the existing concrete 10 and the structural strength, and whether a sufficient working space can be obtained. It differs depending on the situation. Hereinafter, a method of reinforcing the common groove 30 and the tunnel 40, which are typical concrete structures, will be described.

A) Method of Reinforcing Ceiling 30a in Joint Groove 30 (See FIG. 3) A method of reinforcing the ceiling 30a (existing concrete) in the common groove 30 having a rectangular cross section buried in the ground 35 will be described. In this case, the surface of the ceiling portion 30a is often not smooth, and there is little need to secure an inner space cross section. Therefore, a joining method using both the filler 21A and the anchor bolt 23A (or a joint using only the filler 21A) Method)
It is preferred to use First, the simple support 31 for supporting the reinforcing panel P1 is installed, and the support member 32 is placed on the simple support 31. Then, a predetermined filling interval L1 is secured, and the reinforcing panel P1 is installed on the support member 32. Subsequently, the anchor bolts 23A are inserted through the ceiling portion 30a from the front side of the reinforcing panel P1 to fix the reinforcing panel P1. Further, using a grout pump (not shown), a high-strength non-shrinkable mortar, which is the filler 21A, is injected into the filling interval L1, and the two are integrated. Then, after the work is completed, the simple shoring 31 and the support member 32 are removed.

The following remarkable effects can be obtained by performing the above-mentioned reinforcement using the reinforcing panel P1 of the present invention. Since the surface of the carbon fiber sheet is covered with a high-strength flexible board, it does not generate rust or conduct electricity, and has excellent water shielding, so that the existing concrete after installation has good durability. Can be. There is no need to carefully treat the foundation of the existing concrete, and since the work of removing the existing concrete is not required, the working environment is good and there is no need to perform industrial waste treatment. Since the reinforcing panels are manufactured at the factory, there is no need to weld steel plates or attach carbon fiber sheets directly to existing concrete.Therefore, there is no variation in quality due to the skills of workers, and stable quality is ensured. Can be. Since the reinforcing panel is fixed by the anchor bolt, there is no danger that the reinforcing panel will be peeled off or dropped, and extremely high safety can be secured. Since the specific gravity of the reinforcing panel is about 1.6 to 1.8,
Since it is extremely light and the work itself is easy, a special machine / equipment is not required, and the work can be performed with a known general-purpose machine / equipment.

B) Method of reinforcing cold joint 41a of secondary lining concrete 41 in tunnel 40 (see FIG. 4) Secondary lining concrete 4 in tunnel 40 in service
A method of reinforcing the cold joint 41a will be described. As shown in FIG. 4A, the tunnel 40 is composed of a sprayed concrete 45 and a secondary lining concrete 41. As shown in FIG. 4B, the side wall surface of the secondary lining concrete 41 is provided. A cold joint 41a is formed in the longitudinal direction of the above. In the case of this embodiment,
Since the tunnel 40 is in service and it is necessary to secure the inner space section 42 and to shorten the construction time, a joining method using the adhesive 22B and the anchor bolt 23B (or the adhesive 22B) It is preferable to use a bonding method using only the above.

Specifically, first, the cold joint 4
The reinforcing panel P2 is attached so that 1a is located substantially at the center. At this time, an epoxy resin as the adhesive 22B is applied to the entire area of one side of the reinforcing panel P2 with a thickness of 2 mm to 8 mm, and is pressed and adhered to the surface of the secondary lining concrete 41. At this time, it is necessary to continue pressing the reinforcing panel P2 until the adhesive 22B is cured. The pressing time varies depending on the type of the adhesive 22B and the temperature inside the tunnel 40, but is generally 10 minutes to 30 minutes.

Normally, in this state, the reinforcing panel P2 is integrated with the secondary lining concrete 41, so that the reinforcing effect is sufficient.
There is a risk of peeling off and leading to a major accident. for that reason,
In order to secure sufficient safety, the reinforcement panel P2 can be completely reinforced by fixing the reinforcement panel P2 from the inside of the tunnel 40 with four or more anchor bolts 23B per sheet.

By performing the reinforcement using the reinforcing panel P2 of the present invention, the following remarkable effects can be obtained in addition to the effects obtained in the case of the reinforcing method in the common groove 30. Since a panel with a built-in carbon fiber sheet is used, the structural strength can be quickly and easily added by simply applying it to the surface of existing concrete. Since the work process at the site only requires attaching the reinforcing panel, the construction time is completed in 20 to 30 minutes per panel. Therefore, the work can be completed in a very short time, and the construction can be performed in the tunnel in operation without stopping the traffic of the vehicle. In addition, since the thickness of the reinforcing panel can be made extremely thin, that is, 10 mm or less, an inner space cross section (vehicle limit) of the tunnel can be secured. When applied to tunnel cold joints,
Since the existing concrete can be supported on the entire surface of the panel, it is possible to effectively prevent the soul of the existing concrete from falling.

The existing concrete described in the above embodiment is not limited to a common ditch or a tunnel, but can be applied to various structures. For example, the present invention can be applied to surface reinforcement of a cement silo or the like. However, since the reinforcing panel is lightweight, there is no need to change or reinforce the foundation, and it is very effective.

[0036]

EXAMPLES [Structural Strength Test (Bending Test) of Reinforced Panel P] A concrete specimen reinforced by using the reinforcement panel P having the above-described configuration (hereinafter referred to as a "reinforcement specimen (NO1 to NO
4))) will be described by taking the results of a bending test as an example. As shown in FIG. 5A, the reinforced specimen (N
O1 to NO4) are base reinforced concrete beam members (10
cm × 10 cm × 60 cm) (hereinafter referred to as “beam member 50”), the reinforcing panel P (7 mm × 10
cm × 60 cm), and the two were bonded by the following four methods. As a comparative example, an unreinforced concrete specimen (hereinafter, referred to as “unreinforced specimen NO5”) composed of only the beam member 50 was prepared. The bending test was performed by supporting both ends of the lower surface of each of the specimens NO1 to NO5, applying a load W (ton) to the center of the upper surface of the beam member 50, and measuring the central displacement t (mm).

Here, the reinforcing specimen NO1 is the beam member 50
And a reinforcing panel P, a filling gap L of 10 mm is provided, and the filling gap L is filled with a high-strength non-shrinkable mortar as a filler 21 (FIGS. 2A and 5).
(A)). In addition, the reinforcing specimen NO2 is
A gap 10 L of 10 mm is provided between the reinforcing gap P and the reinforcing panel P, and an epoxy resin is filled between the gaps L as the filler 21 to be integrated (FIGS. 2A and 5).
(A)). Further, the reinforcing specimen NO3 is formed by applying an adhesive (epoxy resin) to the reinforcing panel and joining the reinforcing panel to the beam member 50 (FIG. 2).
(B) and FIG. 5 (a)). In addition, reinforcement specimen NO4
Provides a filling gap L of 10 mm between the beam member 50 and the reinforcing panel P, and fills the filling gap L with a high-strength non-shrinkable mortar as a filler material 21;
3 (FIGS. 2 (c) and 5 (a)).
reference).

FIG. 6 is a graph and a table showing the results of the bending test of the specimen. According to this result, the unreinforced specimen N
O5 (Comparative Example) cannot withstand a load of about 1.8 tons or more, whereas the reinforcing specimens NO1 to NO4 have about 4.
It turns out that it can withstand the load of 5 to 5.7 tons. As is clear from the test results, the unreinforced specimen N
Reinforcement specimens NO1 to NO4 are about 2.5
The reinforcement effect is doubled to tripled. This value can be evaluated as having the same properties as reinforced concrete when the amount of reinforcing steel is increased about 4 to 5 times and the concrete thickness is set to 60 cm.

According to these test results, all of the present inventions have the necessary structural strength, and the reinforcement panel and the existing concrete can be easily integrated. It turns out that addition is possible. The maximum load of the reinforcing specimens NO1 and NO4 is
The reason why the strength of the reinforcing specimens NO2 and NO3 is larger than the maximum load is that the high-strength non-shrink mortar (10 cm) and the high-strength non-shrink mortar (10 m
m) and the reinforcing panel (7 mm) are completely integrated, so that the high-strength non-shrink mortar and the reinforcing panel (17 m)
It is presumed that the cross-sectional dimension of the specimen increased by m) and a so-called cross-sectional effect appeared.

[0040]

As described above, according to the present invention, the desired structural strength can be ensured in spite of the simple structure, and good quality is maintained even after the construction without rust or peeling. It is possible to further provide a concrete structure reinforcing panel excellent in workability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a reinforcing panel of the present invention.

FIGS. 2 (a), (b), (c), and (d) are cross-sectional views showing existing concrete reinforced using the reinforcing panel of the present invention.

FIG. 3 is a sectional view showing a common groove reinforced using the reinforcing panel of the present invention.

FIG. 4 is a diagram showing a tunnel reinforced using the reinforcing panel of the present invention. (A) is a sectional view, and (b) is a side view as viewed from the inside of the tunnel.

FIG. 5 is a side view showing a concrete specimen for a bending test, in which (a) is a concrete specimen reinforced using the reinforcing panel of the present invention, and (b) is an unreinforced concrete specimen (comparative example). It is.

FIG. 6 is a graph and a table showing the results of a structural strength test (bending test) of a concrete specimen.

[Explanation of symbols]

 P, P1, P2 Reinforcement panel C Carbon fiber sheet F High-strength flexible board B Adhesive L, L1 Fill gap 10 Existing concrete 21, 21A Filler 22, 22B Adhesive 23, 23A, 23B Anchor bolt 30 Joint groove 30a Ceiling DESCRIPTION OF SYMBOLS 31 Simple support 32 Support member 35 Ground 40 Tunnel 41 Secondary lining concrete 41a Cold joint 42 Inner space section 45 Shotcrete NO1 to NO4 Reinforced specimen NO5 Unreinforced specimen 50 Beam member

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Sada Nakano 2-31-11 Nihonbashi-Ningyocho, Chuo-ku, Tokyo Nissinbo Engineering Co., Ltd. In-house F-term (reference) AK53C BA03 BA06 BA10A BA10B DG01A DG01B DG11C EJ82C GB07 GB31 JK01 JL05

Claims (1)

[Claims] 1. A panel used for reinforcing a concrete structure, wherein a carbon fiber sheet is interposed between flexible boards.
A reinforcing panel for a concrete structure, which is integrally formed with an adhesive.