JPH09235893A - Fire resisting fiber reinforced concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide structure capable of preventing destruction of concrete and a structure due to dead weight, an earthquake, etc., having a fire resisting property, not burning nor fuming. SOLUTION: A fire resisting fiber reinforced concrete structure is constituted by laminating reinforcing fiber and room temperature hardening resin on a surface of a concrete structure and applying nonflammable paint 3 to the surface after hardening it. At this time, carbon fiber, glass fiber, alamide fiber, etc., can be listed as the reinforcing fiber, and it is favorable that the incombustible resin is foaming fire resisting paint to foam and expand at higher than specified temperature of film surface temperature or self-extinguishing paint to generate moisture when the film surface temperature becomes higher than the specified temperature. It is possible to thin the film of these nonflammable paint 3 in comparison with a conventional inorganic compound, it is easy to apply and excellent in outer appearance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete structure such as a pillar of a structure, and more particularly to a fiber reinforced concrete structure having a fire resistant reinforcing layer on the outer surface thereof and excellent in compression strength.

[0002]

2. Description of the Related Art A concrete structure such as a building is constantly subjected to external stress due to a vibration such as an earthquake or a negative load of the structure. Conventionally, a concrete structure has been reinforced by embedding a linear or rod-shaped core made of a reinforcing bar or fiber reinforced plastic (FRP).

However, cracks are generated from the surface of the concrete structure due to a sudden impact or vibration such as a long-term stress or earthquake. The cracks generated from the surface eventually reach the inside, increasing the axial strain, and rupturing from the reinforcing core of the concrete structure.

Therefore, when a crack has occurred in an existing concrete structure, concrete has been applied to reinforce and repair the crack so as to fill the cracked portion. However, even if the cracked part is reinforced with concrete, the strength is insufficient, and furthermore, cracks cannot be prevented by this method.

Therefore, a steel plate is attached to the outer surface of the concrete structure along the circumferential direction of the columnar body for reinforcement, or high strength reinforcing fibers such as carbon fiber, glass fiber and aramid fiber are integrally solidified by a solidifying material. A method has been taken to improve the load bearing capacity of a structure by providing a reinforcing layer formed by molding.

[0006]

However, when a steel sheet is used, the steel sheet itself is heavy, so that a heavy machine is required to attach it, and the weight of the steel sheet itself is added to the concrete structure. There is. Further, when the concrete structure has a complicated structure, it is necessary to deform the steel plate.

The high-strength reinforcing fiber solidified with a solidifying material is called Fiber Reinforced Plastic (FRP), and since it is sheet-shaped, it can flexibly cope with concrete structures of complicated shape and is equivalent to steel plate reinforcement after solidification. Since it has a reinforcing effect, it has good workability and does not generate rust.

However, the fiber reinforced plastic is inferior in fire resistance to the steel plate, and may burn or smoke when a fire occurs.

Therefore, it has been studied to coat or spray an inorganic compound such as gypsum or mortar on the surface of the fiber reinforced plastic reinforcement. However, with an inorganic compound, 1 cm ~
Not only is it necessary to apply a relatively thick coating of about 3 cm, which is not only time-consuming for construction, but also the concrete column itself becomes large and the living volume decreases, which is inefficient.

[0010]

In order to solve such problems, the present inventors have earnestly studied, and as a result, after laminating a reinforcing fiber and a room temperature curable resin on the surface of a concrete structure and curing it, Furthermore, they have found that a fire-resistant fiber-reinforced concrete structure having a flame-retardant coating applied on its surface is useful.

The fiber-reinforced plastic of the present invention for this purpose can be obtained by laminating high-strength fibers such as carbon fibers, glass fibers and aramid fibers and a room temperature curable resin. Examples of the room temperature curable resin include epoxy resin and acrylic resin. As the epoxy resin, a mixture of a compound having a glycidyl group and an amine compound is used. For example, ThreeBond 2082, ThreeBond 2
084 (manufactured by ThreeBond Co., Ltd.) can be mentioned. As the acrylic resin, a compound having an unsaturated double bond mixed with a radical generator is used, and examples thereof include a mixture of ThreeBonds 3921 and 3926 and a mixture of ThreeBonds 3923 and 3928 (manufactured by ThreeBond Co., Ltd.).

In the method of laminating the reinforcing fiber and the room temperature curable resin, first, the room temperature curable resin is applied to concrete and the reinforcing fiber is attached. Then, a room temperature curable resin is applied so as to impregnate the reinforcing fibers.

The flame-retardant paint is preferably a foaming fire-resistant paint that foams and expands at a surface temperature of the coating film above a predetermined temperature, or a self-extinguishing paint that generates water when the surface temperature of the coating film exceeds a predetermined temperature.

A foamable refractory paint that expands and expands when the surface temperature of the coating film exceeds a predetermined temperature is foamed, and the coating film before expansion is 1 to 2 mm.
However, when the surface temperature of the coating film exceeds a predetermined temperature, for example, 250 ° C. or more, such as when a fire occurs, the coating material chemically reacts to generate ammonia gas, water vapor or carbon dioxide gas, and the volume starts to expand. Furthermore, when the coating film is heated, the paint becomes 4
It expands to a volume of 0 to 50 times, creates a heat insulating layer made of carbide, and makes it difficult for high temperature heat due to the flame to be transmitted to the fiber reinforced plastic and concrete structure, thereby preventing a rapid temperature rise of the fiber reinforced plastic and producing smoke, Can prevent ignition.

The foamable refractory paint comprises a resin binder, an inorganic filler, a foaming agent and a solvent. As the foaming agent, dicyandiamide, melamine, chlorinated paraffin, phosphate and the like are used. These foaming agents are decomposed by heat at a temperature of about 200 ° C. or higher, and are foamed and expanded by the generation of incombustible ammonia gas or carbon dioxide and the removal of water, and exert a flame extinguishing effect.

A self-extinguishing paint that produces moisture when the surface temperature of the paint film exceeds a predetermined value has a film thickness of 1 to 2 mm, but the paint itself has the property of being self-extinguishing and having the property that the temperature does not easily rise even when heated. When the surface temperature of the self-extinguishing paint becomes higher than a predetermined value, for example, 300 ° C. or higher due to a fire or the like, moisture lurking inside the paint is generated to lower the temperature of the paint film. The principle of this generation of water is that it is due to a chemical reaction or that the water that is physically adsorbed is released by heating.

The self-extinguishing paint comprises a resin binder, an inorganic filler, a water-generating agent and a solvent. Examples of the water generator include hydrates having water of crystallization, zeolite, alkali metal silicates, and the like.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The fire-resistant concrete structure of the present invention will be described below with reference to examples. However, the present embodiment is an example of some forms of the present invention and is not limited to these forms.

The surface of the concrete on which the reinforcing fiber material of the concrete structure is to be attached is ground with a sander. Next, after removing the polishing powder on the polishing surface, degreasing is performed using an organic solvent, and a primer is applied to the polishing surface. As the primer, a mixture of a bisphenol type epoxy, a modified fatty acid polyamine and a silane coupling agent diluted with a solvent was used.

After the primer was cured, a room temperature curable resin was applied in a uniform thickness. As the room temperature curable resin, ThreeBond 2082 (manufactured by ThreeBond Co., Ltd.) was used.
Before the room temperature curable resin was cured, carbon fibers were attached and the same room temperature curable resin as described above was applied and impregnated. Further, carbon fibers were attached and a room temperature curable resin was applied and impregnated. A spatula was used to remove excess room temperature curable resin to a uniform thickness. This was cured and cured for 24 hours.

After curing, a flame-retardant paint was applied to the surface of the fiber reinforced plastic layer by a roller. As a flame retardant paint, Unitherm No. 38303WB (manufactured by Furukawa Electric Co., Ltd.) was used.

FIG. 1 shows these embodiments. In the figure, 1 is a concrete structure, 2 is a fiber reinforced plastic, and 3 is a flame retardant paint. When the reinforced concrete structure of the present invention is heated to a high temperature due to fire or the like and the surface of the concrete structure rises, the applied paint 2 foams as shown in FIG. 2 and the volume starts to expand. When the concrete structure of the present invention is further heated, the paint 2 foams and expands to a tens of times as much rest space as the coating film when applied. Then, the paint that has foamed and expanded to tens of times that of the coating film makes it difficult for high temperature heat due to a fire to be transmitted to the concrete structure, and can protect the fiber reinforced plastic layer and the concrete layer.

[0023]

According to the present invention, the reinforcing layer formed by the fiber-reinforced plastic made of the reinforcing fiber and the room temperature curable resin concentrates on a part of the columnar body and disperses the external stress applied to the entire concrete structure. Prevents cracking from the outer surface of concrete structures.

Also, the fiber-reinforced plastic is excellent in heat resistance and fire resistance and does not burn or smoke due to fire or the like. Further, it is possible to prevent the explosion of the concrete structure caused by the moisture contained in the concrete at the time of fire.

Further, concrete is basic and neutralized by atmospheric gas, rain, etc. However, according to the present invention, since moisture does not reach the concrete due to the fiber reinforced plastic and the flame-retardant paint, the atmospheric gas is completely removed. In addition, it is possible to block acid rain and prevent deterioration due to neutralization.

[0026]

[Brief description of drawings]

FIG. 1 Concrete structure of the present invention

FIG. 2 is a cross-sectional view showing a state in which the surface of the concrete structure has begun to be heated.

[Explanation of symbols]

1 Concrete layer 2 Fiber reinforced plastic layer 3 Flame retardant paint

Claims (2)

[Claims] 1. A fire resistant fiber reinforced concrete structure characterized in that a reinforcing fiber and a room temperature curable resin are laminated on the surface of a concrete structure, cured and then a flame retardant paint is applied to the surface. 2. The flame-retardant paint is a foaming fire-resistant paint that foams and expands when the surface temperature of the coating film exceeds a predetermined temperature, or a self-extinguishing paint that generates water when the surface temperature of the coating film exceeds a predetermined temperature. The refractory fiber reinforced concrete structure according to claim 1.