JPH04336243A - Fiber reinforced resin reinforced cementituous structure and method for reinforcing the same structure - Google Patents

Abstract

PURPOSE:To reinforce a cementituous structure not causing a problem such as the lowering of reinforcing effect due to deterioration during long-time use, excellent in reliability, having high strength and capable of being simply applied even in the open air. CONSTITUTION:An FRP reinforced cementituous structure is formed by bonding a FRP layer and a resin film layer (4) to the outer surface of a cementituous structure (1). The cementituous structure is reinforced by laminating a reinforcing fiber base material (2) and a resin film (4) to the cementituous structure (1) and evacuating the interior of the film (4) using a sealing material (5) to impregnate the base material with a thermosetting resin (10).

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to fiber-reinforced resin-reinforced cementitious structures and methods of reinforcing cement-based structures, and more particularly to bridge decks made of concrete reinforced with fiber-reinforced resin layers. The present invention relates to cement-based structures such as bridge piers and wall materials made of mortar, and methods for reinforcing cement-based structures.

0002

[Background Art] Recently, bridges have been destroyed by earthquakes, rusting of reinforcing bars has occurred due to neutralization of concrete, fatigue of reinforcing bars reinforcing bridge decks due to rapid increase in traffic, and fatigue of reinforcing bars on building exterior walls. The fragility and durability of cement-based structures have become social issues, such as walls falling due to cracks. Of course, it would be fine to update it to a new one, but that would require a huge amount of money. As a countermeasure for this, for example, bridge decks are reinforced by gluing steel plates to the bottom of the concrete slabs, but this is done at high places with poor footing, and moreover, when workers are on top of them. There is the problem of having to install heavy steel plates while facing the surface, which makes the work difficult for elderly people in particular, and the problem of inefficiency as the installation of steel plates on uneven surfaces requires scraping the concrete until it is smooth. There is.

On the other hand, a method of reinforcing the concrete surface of the slab by laminating reinforcing fiber base materials one by one and impregnating them with resin has been attempted, but since the work is done outdoors, reinforcing fibers are The base materials are blown by the wind, making it difficult to stack them in a predetermined direction and at a predetermined location. In addition, during impregnation work, the reinforcing fiber base material may be damaged by the impregnating roller, the fiber orientation may be disturbed, resin may fall from above and stick to the worker's face, or reinforcing fiber waste may pierce the worker's skin. There was a problem. Another problem is that when exposed to ultraviolet rays or rain for a long period of time, the resin in the fiber-reinforced resin layer deteriorates and the reinforcing effect weakens.

[0004] Also, unlike the case of the above-mentioned bridge, it does not require a huge amount of money to replace the exterior walls of a building with a new one, but in the case of a supermarket, for example, it is necessary to suspend operations and carry out replacement work. This creates business problems.

[0005]

[Problems to be Solved by the Invention] In order to solve the above-mentioned problems, it is an object of the present invention to provide a highly reliable and high-strength product with fewer problems such as reduction in reinforcing effect due to deterioration even during long-term use. An object of the present invention is to provide a cement-based structure and a reinforcing method for a cement-based structure that can be easily constructed even outdoors.

The fiber-reinforced resin-reinforced cement-based structure of the present invention, which meets this objective, has a fiber-reinforced resin layer formed by adhesion on the outer surface of a structure made of a cement-based material, and a resin film layer further bonded thereon. It consists of what is formed by.

[0007] Furthermore, the method for reinforcing a cement-based structure of the present invention includes laminating a reinforcing fiber base material on the outer surface of a structure made of a cement-based material, and then covering the reinforcing fiber base material with a resin film. The method consists of bagging the bag, reducing the pressure inside the bag, injecting a thermosetting resin into the bag to impregnate the reinforcing fiber base material with the thermosetting resin, and then curing the reinforcing fiber base material.

[0008] The cement-based structure as used in the present invention refers to a structure made of cement-based materials such as mortar and concrete, and refers to building materials used for architecture, civil engineering structures, walls, and the like. Further, the cement structure of the present invention is an FRP reinforced cement in which a fiber reinforced resin (FRP) layer containing a reinforcing fiber base material is formed by adhesion on the outer surface of the structure, and a resin film layer is further formed by adhesion thereon. It is a system structure. The FRP layer is formed by impregnating a reinforcing fiber base material with resin. The reinforcing fiber base material may be a single layer, but from the viewpoint of reinforcing a cement-based structure, it is desirable to have a laminated structure of a plurality of reinforcing fiber base materials.

Types of reinforcing fiber base materials include bidirectional fabrics in which reinforcing fiber threads made of multifilament or monofilament reinforcing fibers are arranged in two directions, and reinforcing fiber threads in one direction and auxiliary threads in other directions. A sheet-like unidirectional base material made by arranging reinforcing fibers in parallel and bonding them with threads coated with adhesive, or by bonding thin woven fabrics, non-woven fabrics, or mats together and holding them together. Alternatively, it may be a chopped strand mat in which reinforcing fibers are randomly oriented.

[0010] The reinforcing fibers used in the present invention include carbon fibers,
High modulus and high strength fibers such as glass fibers, polyaramid fibers, and silicone fibers. Cement-based structures have a high elastic modulus, so in order to obtain a sufficient reinforcing effect, it is necessary to use fibers with high elastic modulus and high strength. Carbon fiber is preferred because it has excellent properties. Note that the reinforcing fiber threads constituting the reinforcing fiber base material are not necessarily limited to one type of these fibers, and may be combined with other fibers.

[0011] If a room temperature curing thermosetting resin is used as the matrix resin in the FRP layer, the resin will harden if left at outside temperature after injection.
This is preferable because it simplifies reinforcement work for cement-based structures, but
If necessary, a heat-curable thermosetting resin may be used and the resin may be heated and cured using a hot plate or the like. Examples of the thermosetting resin used in the present invention include epoxy resins, unsaturated polyester resins, and phenol resins, among which epoxy resins are preferred because they have good adhesion to cement structures and reinforcing fibers.

[0012] The type of resin forming the resin film layer is as follows:
Although not particularly limited, it is preferable to use a film made of nylon resin, polyester resin, polyphenylene sulfide resin, polycarbonate resin, or the like because it is less likely to deteriorate not only due to wind and rain but also due to ultraviolet rays. Furthermore, the colors of carbon fibers and polyaramid fibers are black and yellow, and these do not change even if they are made of FRP. Therefore, the color of the reinforced bridge may turn black or yellow, which may cause discomfort to people. In such cases, it is better to use a gray film, which is similar in color to the concrete. Furthermore, it is possible to improve the amenity feel by using films of various colors as required.

Next, a method for reinforcing a cement structure according to the present invention will be explained with reference to the drawings. FIG. 1 shows a method for reinforcing a cement structure according to an embodiment of the present invention. First, the reinforcing fiber base material 2 is laminated on the outer surface of the cement structure 1 to be reinforced. In this example, four reinforcing fiber base materials 2 are laminated, and a bleeder 3 is placed around them. These are covered with a bag film 4 made of a resin film, the cement structure 1 and the bag film 4 are bonded together with a sealant 5 placed on the outside of the bleeder 3, and the reinforcing fiber base material 2 and the bleeder 3 are bagged with the film 4. . A suction port 6 is attached to the bleeder 3, and a resin introduction port 7 is attached to the outermost reinforcing fiber base material, and the resin 10 is supplied from the resin tank 9 while reducing the pressure inside the bag from the suction port 6 with a vacuum pump 8. A reinforcing fiber base material 2 is impregnated with a resin 10. The resin 10 flows from the resin introduction port 7 to the suction port 6 while impregnating the base material 2, and the entire surface of the reinforcing fiber base material 2 is impregnated with the resin 10. If a trap 11 is provided between the suction port 6 and the vacuum pump 8, even if there is a part of the reinforcing fiber base material 2 that is not impregnated with resin, the resin will be kept in the trap 11 until the entire surface is impregnated with the resin. It can be sucked with the vacuum pump 8 while flowing,
Even if the suction is continued, troubles such as resin entering the vacuum pump 8 do not occur, which is preferable. After resin impregnation, the introduction port 7 and the suction port 6 are removed and the resin is cured. In addition,
In FIG. 1, an example in which the number of layers of the reinforcing fiber base material 2 is four is explained, but the number is not necessarily limited to four, and the number of layers, that is, the amount of reinforcing fibers can be determined as necessary. Further, the position of the resin introduction port and the position of the suction port are not necessarily limited to the positions shown in FIG. 1, but are appropriately selected so that the entire surface of the reinforcing fiber base material is impregnated with the resin.

[0014] Normally, when repairing or reinforcing cement-based structures, a highly viscous resin is used to prevent the resin from dripping from the top to the bottom and to prevent the resin from scattering during the impregnation process. However, according to the method of the present invention, there is no such problem and it is possible to use a resin having a relatively low viscosity of 3 to 20 poise.

When reinforcing the lower surface of a cement-based structure, in order to prevent the reinforcing fiber base material from falling, the cement-based structure is coated with the same resin as the matrix of the reinforcing fibers in advance, and the reinforcing fiber base material is coated on the cement-based structure in advance. After repeating resin application and lamination, such as laminating the base material, applying resin to the base material, and laminating the base material, it is preferable to bag the base material with a film. By using a bag to impregnate the reinforcing fiber base material with resin, there is no need for impregnation work using rollers, etc., so there are no problems with damage to the reinforcing fibers, disordered fiber orientation, falling resin, or falling reinforcing fiber waste. can avoid. Further, as a measure to prevent the reinforcing fiber base material from falling, 0.5 to 5% by weight of a low melting point thermoplastic polymer may be attached to the base material and thermally bonded with an iron or the like.

[0016] As a repair before laminating the reinforcing fiber base material, if there are cracks in the reinforced parts of the cement structure, epoxy resin putty can be embedded in the cracks to prevent water leakage. It is preferable to keep it. F
If water leaks from the cracked portion after bonding the RP layer, there is a risk that the FRP layer will peel off from the cement-based structure due to volume expansion due to freezing of the water. In addition, if the surface of the cement structure is uneven, the reinforcing fiber base material has a drape property and will follow the slight unevenness, but if the degree of unevenness is large, the surface of the cement structure can be ground with a grinder. In order to smoothen the surface and improve adhesion with the FRP layer, it is preferable to apply an epoxy resin primer.

It is also possible to peel off the bag film after curing the matrix resin and paint the surface of the FRP layer with urethane paint or acrylic paint, but by leaving the bag film on without peeling it off, UV rays It is possible to prevent the deterioration of the matrix resin due to oxidation, and it is also possible to provide a decorative effect.

In the method for reinforcing a cement structure of the present invention as described above, by leaving the bag film as it is without peeling it off after the thermosetting resin has hardened, for example, a fiber reinforced resin as shown in FIG. Reinforced cementitious structures are easily obtained. FIG. 2 shows a fiber-reinforced resin-reinforced cement structure according to an embodiment of the present invention, in which an FRP layer 23 containing a reinforcing fiber base material is adhered to the lower surface of a deck slab 22 of a bridge 21 made of reinforced concrete. Furthermore, a resin film layer 24 is adhered thereon.

In such a bridge 21, the deck slab 2
2 is sufficiently reinforced by the FRP layer 23,
The resin film layer 24 prevents the FRP layer 23 from being directly exposed to wind and rain, prevents the resin of the FRP layer 23 from deteriorating, and maintains the reinforcing effect for a long period of time.

[0020]

Effects of the Invention When using the fiber-reinforced resin-reinforced cement structure of the present invention, since the FRP layer and the resin film layer are formed by adhesion on the outer surface of the cement structure, the FRP of the reinforced cement structure is There is little deterioration of the layer resin over time. Moreover, if the FRP layer is composed of a carbon fiber reinforced resin layer, reinforcement can be achieved with a small amount of fibers, and the reinforcement work becomes easy. Carbon fiber has excellent fatigue properties,
Moreover, since it has excellent alkali resistance, there is little concern that the reinforcing fibers of the FRP layer will deteriorate even after a long period of time.

[0021] Furthermore, in the reinforcing method for cement-based structures of the present invention, reinforcing work is carried out by impregnating and curing resin with a bag, so even when working outdoors, the reinforcing fiber base material is not blown by the wind. In addition, during the resin impregnation process, the reinforcing fibers may be damaged by the impregnation roller, the fiber orientation may be disturbed, or the resin may fall from above. There is less worry that reinforcing fiber waste will stick to the worker's face or that the reinforcing fiber waste will pierce the worker's skin, and reinforcing work can be carried out easily and in a short time.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a method for reinforcing a cement structure according to an embodiment of the present invention.

FIG. 2 is a perspective view of a fiber-reinforced resin-reinforced cement structure according to an embodiment of the present invention.

[Explanation of symbols]

1 Cement-based structure 2 Reinforcement fiber base material 3 Breeder 4, 24 Resin film layer 5 Sealing material 6 Suction port 7 Resin introduction port 8 Vacuum pump 9 Resin tank 10 Resin 11 Trap 21 Bridge 22 Floor slab 23 Fiber reinforced resin (FRP) layer

Claims (3)

[Claims] 1. A fiber-reinforced resin-reinforced cement, characterized in that a fiber-reinforced resin layer is formed by adhesion on the outer surface of a structure made of a cement material, and a resin film layer is further formed by adhesion thereon. system structure. 2. The fiber-reinforced resin-reinforced cement structure according to claim 1, wherein the reinforcing fibers of the fiber-reinforced resin layer are carbon fibers. 3. A reinforcing fiber base material is laminated on the outer surface of a structure made of cement material, a resin film is further placed on top of the reinforcing fiber base material, the reinforcing fiber base material is placed in a bag, the pressure inside the bag is reduced, and the reinforcing fiber base material is placed in a bag. A method for reinforcing a cement-based structure, which comprises injecting a thermosetting resin to impregnate a reinforcing fiber base material, and then curing the thermosetting resin.