JP2717791B2 - Building reinforcement method using carbon fiber reinforced plastic plate - Google Patents

Description

Description: TECHNICAL FIELD The present invention has a flat surface, such as for reinforcing beams, floorboards and other various structures of concrete structures, and for waterproofing and preventing air leakage of the structures. The present invention relates to a method for strengthening a structure including repair of the structure, and particularly relates to a method for reinforcing a structure in which such reinforcement is performed using a carbon fiber reinforced plastic plate.

2. Description of the Related Art Beams, floor slabs, and other various structures of concrete structures deteriorate over time, and their strength is reduced due to the effects of bending stress, etc., and reinforcement is required. In some cases, waterproofing, air leakage prevention, etc. Various repairs need to be performed.

Conventionally, for strengthening a structure having such a flat surface, for example, an iron plate is used as a reinforcing material to recover a decrease in strength due to deterioration of a floor slab (concrete slab) of a concrete structure. There has been a method of fixing to a reinforcing portion by using. Such a reinforcing method is heavy due to the fact that the reinforcing material is an iron plate, and it is difficult to handle the reinforcing material in a large-area reinforcing operation. There was a problem that the work efficiency was often very difficult and poor.

In order to solve such a problem, the weight is extremely light, the method of attaching and fixing to the surface to be reinforced is easy, and the tensile strength and elastic modulus are large, and furthermore, weather resistance, water resistance,
A reinforcing method using a carbon fiber reinforced plastic plate having excellent heat resistance and the like as a reinforcing material has been proposed.

The reinforcing method using such carbon fiber reinforced plastic plate as a reinforcing material or a repair material for other purposes is very suitable for concrete slabs, and also for reinforcing various structures, waterproofing and air. It is capable of repairing and strengthening such as leakage prevention, and has various advantages that the material used is extremely lightweight, so that its handling is easy and the working efficiency is improved.

According to a conventionally proposed reinforcing method using a carbon fiber reinforced plastic plate, as shown in FIG.
For example, in order to attach the carbon fiber reinforced plastic plate 2 to the surface of the concrete slab 1, first, an adhesive 3 or a primer and an adhesive are applied to the surface of the concrete slab, and then the carbon fiber reinforced plastic reinforcement plate 2 is attached. Needed. At this time, generally, the surface of the concrete slab is rarely a uniform plane and is in an uneven state. Therefore, when the adhesive 3 is applied to the surface of the concrete slab with a uniform thickness, and the carbon fiber reinforced plastic reinforcing plate is stuck thereon, a void 4 is formed between the reinforcing plate and the adhesive. . The presence of such voids 4 caused a reduction in hardening by the carbon fiber reinforced plastic reinforcing plate 2. Such a problem has become a similar problem in other repairs such as waterproofing and air leakage other than reinforcement.

Eliminating the existence of such voids can be solved by increasing the thickness of the applied adhesive, but when the thickness of the adhesive layer is increased, the reinforcing effect is particularly reduced. The result of the research experiment such as was understood. Alternatively, the bonding operation of the carbon fiber reinforced plastic plate is performed very carefully and carefully, or the surface of the concrete slab to which the carbon fiber reinforced plastic plate is bonded is polished with a sanding machine so as to be evenly flat ( It is conceivable to apply a thin adhesive on the concrete surface, but such an operation requires a great deal of time and labor, and such an operation is impossible or extremely difficult depending on a reinforcing place. In some cases,
It was impractical and extremely inefficient.

In order to solve the above problem, it has been proposed to use a carbon fiber reinforced plastic plate in a semi-cured state,
According to the results of research experiments conducted by the present inventors, the flexibility of a semi-cured carbon fiber reinforced plastic plate is low and its handling is not so different from that of a cured plastic plate.
Also, the viscosity of such a semi-cured carbon fiber reinforced plastic plate is not enough to adjust to such irregularities on the surface of the concrete slab, and it is impossible to adhere along the irregularities on the surface of the concrete slab. It was not possible to completely eliminate the gap between the fiber reinforced plastic plate and the adhesive, and it was found that the reinforcing effect was not much different from that of the cured carbon fiber reinforced plastic plate.

Accordingly, an object of the present invention is to provide extremely good workability and prevent the formation of a gap between the reinforcing plate and the surface to be reinforced, and achieve sufficient reinforcement, repair, and other various reinforcing effects. Provided is a method for strengthening a structure having a flat surface, such as reinforcing a beam, a floor slab, and other various structures of a concrete structure, and further waterproofing the structure and preventing air leakage. It is to be.

Another object of the present invention is to provide a beam or floor of a cocrete structure capable of quickly preparing a reinforcing plate having optimum characteristics depending on the type of reinforcement such as reinforcement and repair on site to achieve the reinforcement purpose. Provided is a method of reinforcing a structure having a flat surface for suitably performing reinforcement of a plate or other various structures, and further strengthening a structure having a flat surface, such as waterproofing the structure and preventing air leakage. That is.

Means for Solving the Problems The above objects are achieved by a method for strengthening a construct according to the present invention.

In summary, the present invention provides a step of applying an in-situ hardened soft carbon fiber reinforced prepreg to a flat-plate-like construction surface without pressing air from one end side to the other end side while sequentially pressing the prepreg, and applying the prepreg to pressing means. 50 to 15 while pressing
A step of heating the prepreg to a temperature of 0 ° C. to cure the prepreg; and (a) a flexible plate-like elastic member having a heating means; (B) an airbag having a built-in heating means, an air supply means for supplying air to the airbag, and a support member for pressing the airbag toward the prepreg. Or (c) a bleeder cloth provided with heating means and disposed over the prepreg, and a bag film further disposed over the bleeder cloth; and between the bleeder cloth and the bag film. And a vacuum pump for evacuating the air.

According to one embodiment of the present invention, in-situ cured soft carbon fiber reinforced prepreg is prepared by laminating a plurality of types of prepregs to obtain desired properties depending on the type of reinforcement,
According to another embodiment, the in-situ cured soft carbon fiber reinforced prepreg is affixed to the adhesive-coated construction surface.

First, the in-situ cured soft carbon fiber reinforced prepreg used in the method of the present invention will be described in more detail.

Carbon fiber as a reinforcing fiber ("carbon fiber" in this specification)
Is used to include graphite fibers. ), And using a thermosetting matrix resin composition, a carbon fiber reinforced prepreg is produced by an ordinary method.

More specifically, as the carbon fiber, any commercially available carbon fiber such as a pitch-based carbon fiber and a PAN-based carbon fiber can be used, but it is preferable that the tensile strength be 2.0 GPa or more and the elasticity be 200 GPa or more. High modulus carbon fibers are used. Generally, a filament having a diameter of about 7 to 12 μm
Carbon fibers formed by bunching and binding 3,000 to 24,000 fibers are used.

As the thermosetting matrix resin constituting the matrix resin composition, an epoxy resin, an unsaturated polyester resin, a polyurethane resin, a diallyl phthalate resin, a phenol resin, and the like can be used.
A curing agent and other imparting agents such as a flexibility imparting agent are appropriately selected so that the temperature is 0 ° C. Therefore, to give a preferred example, an epoxy resin is preferable as the thermosetting resin, and usable epoxy resins include, for example, (1)
Glycidyl ether epoxy resin (bisphenol A, F epoxy resin, novolak epoxy resin, brominated bisphenol A epoxy resin); (2) cycloaliphatic epoxy resin; (3) glycidyl ester epoxy resin; (4) Glycidylamine-based epoxy resin;
(5) Heterocyclic epoxy resin: One or more types selected from various other epoxy resins are used, and bisphenol A and F, and glycidylamine-based epoxy resins are particularly preferably used. As the curing agent, diaminodiphenylsulfone (DDS), diaminodiphenylmethane (DDM) and the like are preferably used.

The “soft carbon fiber reinforced prepreg” referred to in the present specification is manufactured using a resin having a viscosity of 100,000 to 500,000 poise at room temperature (15 ° C. to 25 ° C.) or a standard matrix resin for reinforced carbon fiber. 1 weight per 100 carbon fiber reinforced
It is manufactured by adjusting the ratio to 00 to 150, or by mixing the matrix resin variously and adjusting the ratio appropriately.

Further, such a soft carbon fiber reinforced prepreg can be produced in a usual manner, but in brief, a continuous supply of long fiber carbon fibers and a viscosity of 10,000 to 500,000
A thermosetting matrix resin composition that is poise is supplied to carbon fibers, and the carbon fibers are impregnated under pressure and heat using a roll or the like to a predetermined thickness, usually 0.05 to 0.3 mm, in an uncured state. (I.e., in a soft state), it is manufactured by being sandwiched by an upper cover film and wound on a winding roll. By changing the physical properties of the carbon fiber used, the amount used and the arrangement mode, and further by impregnating the matrix resin composition, and by changing the blending ratio of the thermosetting matrix composition used, that is, by changing the properties in various ways Carbon fiber reinforced prepregs are produced that provide various tensile strengths, tensile moduli, and even toughness.

According to the present invention, the carbon fiber reinforced prepreg thus produced is not cured, that is, -20 ° C
Stored at a temperature of about 0 ° C.

The carbon fiber reinforced prepreg may be transported to the site as it is and used for building reinforcement, but a plurality of carbon fiber reinforced prepregs having the same characteristics according to the strength required for the reinforced portion and other characteristics are used. Alternatively, a plurality of carbon fiber reinforced prepregs having different properties are laminated on site or at a factory to prepare a cured in situ soft carbon fiber reinforced prepreg. The soft carbon fiber reinforced prepreg does not need to be stored and transported in a flat state, and can be wound into a roll. By making the soft carbon fiber reinforced prepreg into a roll, the transportability is improved,
Furthermore, as described later, the workability of sticking to the surface to be reinforced is extremely improved. This is one of the great features of the present invention.

Next, a reinforcing method using the soft carbon fiber reinforced prepreg according to the present invention will be described.

FIG. 1 and FIG. 2 show a reinforcing method for reinforcing a concrete slab whose carbon fiber reinforced reinforcing plate is attached to the lower surface of the concrete slab 1 and whose strength is reduced due to deterioration.

According to the present invention, prior to reinforcement of a concrete slab, a soft carbon fiber reinforced prepreg required for the reinforcement is provided.
12 are prepared. That is, depending on the degree of deterioration of the concrete slab to be reinforced, a plurality of soft carbon fiber reinforced prepregs are laminated as needed to provide the required strength and elastic modulus. Such work can be performed on-site, or can be made in a factory before being brought to the site. In any case, when laminating a plurality of soft carbon fiber reinforced prepregs cut to a predetermined size, it is necessary to sufficiently extrude air with a press roll so that air is not sandwiched between the laminations. is important. Such a lamination operation can be performed at normal temperature (50 ° C. or lower).

In this manner, the soft carbon fiber reinforced prepreg 12 formed by laminating as necessary is pressed against the concrete slab 1 at one end as shown in FIG. And a soft carbon fiber reinforced prepreg such that air is not trapped between the surface of the concrete slab 1 and the surface of the soft carbon fiber reinforced prepreg 12.
Attach 12 to the reinforced surface of concrete slab 1 while pressing. Such a sticking operation can be performed manually by an operator, or can be performed by using a manual roller or the like. By this attaching operation, the soft carbon fiber reinforced prepreg 12 is adhered closely along the irregularities on the surface of the concrete slab without forming a void.

According to the present invention, soft carbon fiber reinforced prepreg 12
While it can be stuck to a desired location while maintaining a flat shape, as shown by a dashed line in FIG. 1, it is brought to the site in a state of being wound into a roll, and on a desired surface to be reinforced. The roll-shaped soft carbon fiber reinforced prepreg 12 can be stuck on the surface while rolling, thereby significantly improving the sticking operation.

In the embodiment shown in FIG. 1, the concrete slab reinforced surface to which the soft carbon fiber reinforced prepreg 12 is adhered has an adhesive 13 or a primer (for improving the affinity between the adhesive 13 and the concrete surface). Although an embodiment in which the adhesive 13 is applied after the application of the adhesive 13 (not shown) is shown, according to the present invention, such an application of the adhesive 13 or the like is preferable, but not essential. If the primer,
When an adhesive or the like is applied to the surface of the concrete slab, it is extremely thin, for example, it is desirable to apply a thickness of 2 to 5 mm. Also, an epoxy primer is preferable as a primer, and an adhesive is applied. For example, an epoxy-based adhesive having good affinity with the matrix resin constituting the soft carbon fiber reinforced prepreg to be obtained is suitable.

Next, as shown in FIG. 2, the soft carbon fiber reinforced prepreg is
It is fully heated at 150 ° C and cured.

3 to 5 show another embodiment in which the soft carbon fiber reinforced prepreg 12 attached to the surface of the building, in this embodiment, the surface of the concrete slab, is cured by heating.

In the embodiment shown in FIG. 3, the in-situ hardened soft carbon fiber reinforced prepreg 12 affixed to the concrete slab surface in the same manner as the method shown in FIG. More specifically, the pressing means 15 includes a flexible plate-shaped elastic member 17 having a heating means 16 such as a flexible flat electric heater, and the prepreg 12
And a support member 18 that presses toward this direction. Elastic member
17 is, for example, a heat-resistant sponge rubber having a sufficient cushioning property with a thickness of about 1 to 2 cm, and a support member 18 is a rigid flat plate 18 such as a carbon fiber reinforced plastic plate.
It is preferable that the flat plate 18a is formed of a normal support 18b that can be adjusted in the longitudinal direction by pressing and supporting the flat plate 18a at a predetermined pressure, for example, 0.02 to 0.1 kg / cm ² .

It is preferable to interpose a heat insulating material 16a such as an asbestos sheet between the heating means 16 and the flat plate 18a as shown in the figure.

In the above configuration, the soft carbon fiber reinforced prepreg 12 is pressed against the surface to be reinforced at a predetermined pressure while being heated, and particularly when the soft carbon fiber reinforced prepreg 12 is attached to the lower surface of the building 1 as in this embodiment. It is effective for or,
When such a pressing means 15 is used, the prepreg
12 is evenly pressed against the surface to be reinforced with a predetermined pressing force,
Further, even if a small amount of air remains between the surface to be reinforced and the prepreg, there is an effect that such air is discharged by the pressing means 15.

The pressing means 15 is not limited to the embodiment shown in FIG. 3, and for example, as shown in FIG. 4, an air bag 19 having a built-in heating means 16 such as an electric heater, and an air bag 19 Air supply means for supplying air (not shown)
And a support member 18 for pressing the airbag 19 toward the prepreg.
The support member 18 has a rigid flat plate 18a such as a carbon fiber reinforced plastic plate, as in the case of the above-described embodiment.
It is preferable that the flat plate is formed of a normal support 18b that can be adjusted in the length direction in which the flat plate is supported and pressed at a predetermined pressure. The air bag usually has an air pressure of 0.02 to 0.1 kg / cm ² . The pressing means of this embodiment can also achieve the same effect as the pressing means described with reference to FIG. It is preferable to interpose a heat insulating material 16a such as an asbestos sheet between the air bag 19 and the flat plate 18a as shown in the figure.

FIG. 5 shows another embodiment of the pressing means 15. According to this embodiment, the soft carbon fiber reinforced prepreg 12
A bleeder cloth 20 is arranged so as to cover the outer surface of the above, and a release film 21 is provided thereon. Further, on the release film 21, a flexible flat electric heater 23 sandwiched by a metal foil 22 having a thickness of about 20 μm is provided. The electric heater 23 sandwiched between the soft carbon fiber reinforced prepreg 12, the bleeder cloth 20, the release film 21, and the metal foil 22 is completely covered with the bag film 24. A sealant tape 25 is provided between the outer periphery of the bag film 24 and the surface of the concrete slab, and the both are kept in an airtight state. Next, the air between the bleeder cloth 20 and the bag film 24 is evacuated by a vacuum pump (not shown). The vacuum pressure between the bleeder cloth 20 and the bag film 24 is-
400mmHg is enough. As a result, the soft carbon fiber reinforced prepreg 12 is pressed against the surface of the concrete slab 1 to be reinforced, and is simultaneously heated to a predetermined temperature by the electric heater 23. The pressing means of this embodiment can also achieve the same effect as the pressing means described with reference to FIGS. 3 and 4.

The pressing and heating means 15 is not limited to the above-described embodiment, and various modifications will be conceived by those skilled in the art.

A soft carbon fiber reinforced prepreg is attached to the surface to be reinforced and cured by the above methods, and has a predetermined strength, elastic modulus,
Further, a carbon fiber reinforced plastic plate having toughness is obtained. The carbon fiber reinforced plate may be left as it is, but if necessary, a reinforcing fastener is provided at an appropriate place for reinforcement,
Auxiliary fixing is also possible.

Further, in each of the above-described embodiments, the mode in which the soft carbon fiber reinforced prepreg is attached to the reinforced surface on the lower surface of the structure has been described, but naturally the same applies when the reinforced surface is present on the upper surface of the structure. It will be appreciated that the method can be enhanced in the following manner. If the surface to be reinforced is on the top surface of the structure, for example, as shown in FIG. 6, the pressing means 15 may be a flexible one having a heating means 16 such as a flexible planar electric heater. A plate-shaped elastic member 17 and a rigid flat plate 18a such as a carbon fiber reinforced plastic plate for pressing the elastic member 17 toward the prepreg 12 and a predetermined pressure, for example, 0.02 to 0.1 kg / cm. A weight 18b pressed at ² may be used. Further, it is preferable to interpose a heat insulating material 16a such as an asbestos sheet between the heating means 16 and the flat plate 18a as shown in the figure.

 Next, examples of the present invention will be described.

Example 1 Monofilament 12000 having a diameter of 7 μm as carbon fiber
A yarn obtained by bundling and binding books was used. On the other hand, Bisphenol A epoxy resin EP manufactured by Yuka Shell Epoxy Co., Ltd.
An epoxy resin composition containing 50gr / 50gr of 828 (trade name) / EP1001 (trade name), 4.2 gr of dicyandiamide as a curing agent, and 4.2 gr of DCMU (N-3,4 dichlorophenylene N'-dimethylurea) was prepared. A matrix resin solution having a viscosity of 500,000 poise was prepared.

The matrix resin liquid was impregnated into the carbon fibers arranged in one direction, and heated and pressed at 120 ° C. by a heating and pressing roller to produce a soft carbon fiber reinforced prepreg having a thickness of 0.1 mm. At this time, the amount of carbon fibers with respect to the Matris resin, that is, the impregnation ratio is 100 /
It was 100.

Five soft carbon fiber reinforced prepregs were used to prepare a five-layer test prepreg. At this time, the direction of the carbon fiber in the prepreg of each layer is (0 ° direction) − (0 °).
(° direction)-(90 ° direction)-(0 ° direction)-(0 ° direction)
It laminated so that it might become.

Example 2 On the lower surface of a flat concrete slab, the soft carbon fiber reinforced prepreg for test manufactured in Example 1 was applied by the method according to the example described with reference to FIG.
An experiment was conducted on the reinforcing effect of the concrete slab by attaching it to a concrete slab test piece described below. In this experiment, the epoxy adhesive 13 was applied with a thickness of 2 mm.

The concrete slab test piece 30 used in the experiment was formed into a flat plate having an outer shape of 2800 × 600 × 150 mm ³ as shown in FIG.
10 Similarly, deform the deformed reinforcing bar 31 at a pitch of 120 mm in the width direction.
Ten deformed reinforcing bars 31 were arranged and formed as a whole into a reinforced concrete structure.

The evaluation of the reinforcing effect of the concrete slab test piece 30 was performed as shown in FIG.
Are supported at support points 32, 32 arranged at intervals of 1200 mm, and a concentrated load P / 2 that continuously changes 400 mm inside from the support point 32 is added to the concrete slab test piece 30, and a concrete slab test is performed. The bending stiffness of the piece and the yield strength from the yield load were measured. The experimental results are shown in Table 1.

Comparative Example 1 The same experiment as in Example 2 was performed using the soft carbon fiber reinforced prepreg for test manufactured in Example 1 in an autoclave at a factory to completely cure the carbon fiber reinforced prepreg to obtain a carbon fiber reinforced laminated reinforcing plate. The experimental results are shown in Table 1.

Table 2 shows the experimental results without reinforcement. Comparing Tables 1 and 2, the present invention has an extremely excellent reinforcing effect when compared with no reinforcement, and according to the reinforcing method of the present invention, a fully cured carbon fiber reinforced laminated reinforcing plate was used. It turns out that it has the same bending rigidity and proof stress as a case.

In the description of the above embodiments, the present invention has been described in relation to the repair method for reinforcing the concrete slab, but the present invention is not limited to this. That is, the in-situ cured soft carbon fiber reinforced prepreg according to the present invention is extremely flexible, and can be transported and worked in a state wound in a roll, so that it has good transportability and workability, and any shape. It can be used with a high degree of elasticity after curing and has excellent water resistance, heat resistance, and weather resistance. Can be done.

Effect of the Invention As described above, the method for reinforcing a structure using the soft carbon fiber reinforced prepreg in-situ effect for reinforcing a structure according to the present invention is extremely workable, and has a high workability between the carbon fiber reinforced plastic plate and the surface to be reinforced. Can prevent the formation of voids and achieve a sufficient reinforcing effect, reinforce concrete structures with beams, floor slabs, and other structures having various flat surfaces, and furthermore, waterproof the structures and prevent air leakage. It is possible to suitably enhance the structure such as.

Further, according to the present invention, it is possible to quickly prepare and reinforce a reinforcing plate having the optimum characteristics according to the type of reinforcement at the site, and to use beams, floor slabs, and other various flat surfaces of concrete structures. It is possible to suitably carry out reinforcement of a structure having a flat surface, such as waterproofing of a structure having a flat surface and prevention of air leakage.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are process explanatory diagrams illustrating a method for repairing a building according to the present invention. 3 to 6 are explanatory views for explaining another embodiment of the method for repairing a building according to the present invention. FIG. 7 is an explanatory view illustrating a conventional method of repairing a structure. FIGS. 8 (a), (b) and (c) are a plan view, a side view and a front view, respectively, showing a concrete slab test piece used in an experiment for verifying the effect of the present invention. FIG. 9 is a schematic view showing a method of applying a load to a concrete slab specimen. 1: Concrete slurry 12: Pre-cured soft carbon fiber reinforced prepreg 13: Adhesive 15: Pressing means 16, 23: Heating means 16a: Insulation material 17: Elastic member 18: Support member 19: Air bag 20: Bleeder cloth 24: Bag film

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Noboru Ishikawa 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Minoru Sawade 2-6-1 Kyobashi, Chuo-ku, Tokyo Shimizu (56) References JP-A-63-14945 (JP, A) JP-A-56-69118 (JP, A) JP-A-58-205725 (JP, A) JP-A-62-62740 (JP, A) JP-A-62-135348 (JP, A) JP-A-59-184618 (JP, A) JP-A-53-12964 (JP, A)

Claims (3)

(57) [Claims] 1. A step of affixing an in-situ cured soft carbon fiber reinforced prepreg to one side of a plate-like construction without pressing air from one end side to the other end side, and pressing the prepreg by pressing means. Heating the prepreg to 50 to 150 ° C. while hardening the prepreg, and the pressing means comprises: (a) a flexible plate-shaped elastic member having a heating means; Or (b) an airbag having a built-in heating means, an air supply means for supplying air to the airbag, and a support member for pressing the airbag toward the prepreg. Or (c) a bleeder cloth comprising heating means and disposed over the prepreg, and further comprising a bag film disposed over the bleeder cloth. The bleeder cloth and having a vacuum pump for evacuation of air between the bag film, constructs strengthening method by carbon fiber reinforced plastic plate, characterized in that. 2. The in-situ cured soft carbon fiber reinforced prepreg comprises:
Claim 1 wherein a plurality of types of prepregs are prepared by laminating a plurality of prepregs to obtain desired characteristics depending on the type of reinforcement.
The method described in the section. 3. The in-situ cured soft carbon fiber reinforced prepreg is:
3. A method according to claim 1 or claim 2, wherein the method is applied to the surface of the construction to which the adhesive has been applied.