JPH0539674A - Reinforcing method for structure - Google Patents

Abstract

PURPOSE:To efficiently reinforce a structure by sticking a plate bode impregnated with resin into reinforcing fibers and the like on the surface of a structure element to be reinforced of a structure, coating a solution containing a hardening agent and a solvent, and drying and hardening it. CONSTITUTION:Resin such as phenol resin and epoxy resin serving as a matrix is impregnated into a uniaxial orientation object, a woven fabric, and a nonwoven fabric of fibers such as carbon fibers and glass fibers used as reinforcing fibers to form a plate shape with the thickness of about 0.1-2mm. This plate body is stuck on the surface of a structure element to be reinforced of a structure, a solution containing a hardening agent such as hexamethylenetetramine and aliphatic diamine and a solvent such as ethanol is coated, and it is dried and hardened by forced hot-air drying and the like. The solution is hardened in a short time with good workability regardless of the change of temperature, and the structure can be efficiently reinforced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for reinforcing a structure. More specifically, the present invention relates to a method of reinforcing a structure such as a building, a tank, a chimney, a bridge pier, and a floor board with a prepreg.

[0002]

2. Description of the Related Art Some existing structures are constructed in accordance with old design standards and guidelines, and thus have lower seismic performance than structures based on current standards, and may require seismic reinforcement. In addition, when it is necessary to reinforce the design load for reasons such as increasing the number of building floors when the structure is renovated,
Often it is necessary to reinforce the structure.

As a conventional reinforcing method, the existing column member is surrounded by a steel plate, or the existing column member is surrounded by a welded wire net or a reinforcing bar cage, mainly to improve the toughness of the column member, that is, to prevent some damage such as cracks. Reinforcement methods have been proposed which are intended not to reduce the loading capacity and energy consumption capacity when receiving.

However, in these reinforcing methods, welding work of steel plates and the like at the construction site is indispensable, and welding requires reliable work by a highly skilled worker. In addition, it is difficult to use heavy equipment to carry the steel sheet into the existing building, and if cut into a size that can be carried in manually,
The amount of welding at the construction site increases. It is necessary to inject mortar and the like between the existing column member and the steel plate, welded wire mesh, and rebar cage to transmit the stress, but various problems such as it is not easy to densely fill the mortar etc. Have

Further, in the above-mentioned reinforcing method, generally only the shear strength of the existing column member is increased, and in order to make the bending strength to the same level as before the reinforcing, a slit is provided in the reinforcing member such as a steel plate. There is a need. However, if the reinforcing member located on the outer surface is provided with the slit, the rain conditioned at this portion is deteriorated, and as a result, a water leakage accident is likely to occur. In addition, it becomes necessary to apply rust preventive treatment to the steel sheet, which causes a problem that maintenance costs increase.

A method has also been proposed in which a steel plate is attached to a concrete structure by using an anchor bolt and an adhesive or a grout material to reinforce the bending strength. However, they are not always satisfactory in terms of reinforcement cost and reinforcement period.

A reinforcing method has also been proposed in which high-strength fibers are attached in the form of fiber-reinforced plastics via an adhesive. However, the construction method using fiber reinforced plastic is to attach the fiber reinforced plastic that has been manufactured in advance at the construction site, and if the object to be reinforced is large, it must be divided into smaller pieces for construction. There is a problem that construction becomes complicated depending on the shape of the object.

The structure is a material obtained by impregnating a thermosetting resin into a prepreg, that is, a woven fabric or fibers arranged in a uniaxial direction, that is, it is not sticky at ordinary temperature, is flexible, and is easy to handle. A method has been proposed in which a material is cured into a desired shape by molding and heating and is reinforced with a material that becomes a fiber-reinforced resin composite material (FRP). According to this method, a structure such as a building, a tank, a chimney, a bridge pier, or a floor board is wound or attached with a prepreg reinforced with high-strength carbon fiber or the like to be cured.

The method of curing the prepreg is as follows:
Place in a heating oven or autoclave, 75 ~
The most common method is to heat to about 350 ° C., and this curing treatment usually takes several hours to several days. In order to shorten the curing time, a method of using a prepreg impregnated with a resin having a relatively low curing temperature, or a method of applying a room temperature curable adhesive and curing it has been proposed.

[0010]

In the case of the most common prepreg, which cures at a relatively high temperature, the curing process takes a long time and the productivity is not improved. There is a problem that a heat source such as an oven or a heater is required.

A prepreg impregnated with a resin having a low curing temperature has a problem in storage stability at room temperature, needs to be stored in a refrigerator, has a short pot life, and may be cured during work. is there. In the case of applying a room temperature curable adhesive, it is necessary to use an adhesive having a fast curing speed in order to cure it in a short time, but in this case, workability is remarkably poor and practicality is poor. With these methods, it is difficult to adapt to seasonal temperature changes, such as being impossible to carry out at low temperatures, especially at temperatures below 10 ° C., such as when working outdoors in winter.

An object of the present invention is to solve the above problems and to provide an efficient method for reinforcing a structure by curing a prepreg in a short time with good workability regardless of changes in environmental conditions, particularly temperature. There is

[0013]

According to the present invention, a prepreg is attached to the surface of a structural element to be reinforced in a structure, a solution containing a curing agent and a solvent is applied to the prepreg, and the prepreg is dried and cured. A method of reinforcing a structure is provided.

In the present invention, a curing agent is dissolved in a solvent to be applied as a solution to a prepreg and dried, whereby the curing agent in the solution migrates into the prepreg,
It was completed by finding that it has good workability and can be cured in a short time.

The present invention will be described in more detail below.

The prepreg used in the present invention is not particularly limited. As the resin, any known resin such as phenol resin, epoxy resin, vinyl ester resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin can be used.

The prepreg is a uniaxially oriented fiber used as a reinforcing fiber, a woven fabric, a non-woven fabric, or the like impregnated with a resin as a matrix to form a plate having a thickness of about 0.1 to 2 mm.

Examples of the material of the reinforcing fiber include carbon fiber, glass fiber, alumina fiber, polyethylene fiber, liquid crystal polymer fiber and the like. As the form of the reinforcing fiber,
Examples include uniaxially oriented products, woven fabrics and nonwoven fabrics. Considering the strength at the time of reinforcement, carbon fibers, particularly long carbon fibers, are preferable, and uniaxially oriented products are preferable as the form.

In the uniaxially oriented product, it is preferable that the direction of the fibers is made to coincide with the longitudinal direction of the object to be reinforced, and if necessary, the direction of the fibers is changed to vertical / horizontal, vertical / horizontal / diagonal, etc. You may. Further, the prepreg may be wound while impregnating a high strength long fiber strand such as glass fiber or carbon fiber with a resin. In the winding, a synthetic resin film such as a polyester film is coated as an edging material for the purpose of preventing adhesion with a layer of a solution containing a curing agent applied to the surface of the prepreg, and a high strength long film is formed on the film. It is preferred to wind the fiber strands.

The curing agent used in the present invention may be selected according to the type of thermosetting resin of the prepreg and is not particularly limited. Specifically, hexamethylenetetramine for ordinary phenol resin, polymethylenediamine for epoxy resin, aliphatic diamine such as polyether diamine, diethylenetriamine, triethylenetetramine,
Linear or branched aliphatic polyamines such as aminoethylethanolamine, cycloaliphatic polyamines such as N-aminomethylpiperazine, aliphatic aromatic amines such as xylylenediamine, tetramethylguanidine, triethanolamine and tris (dimethylamino). Secondary or tertiary amines such as methyl) phenol, modified amines such as amine adducts, polyamide curing agents, polyamide adducts, polymercaptan curing agents, polysulfide resins and imidazoles such as 2-ethyl-4-methylimidazole or salts thereof, etc. Is exemplified. Of these, those that exhibit high strength by curing the resin at room temperature are preferably used.

The solvent for dissolving these curing agents is not particularly limited as long as it dissolves a sufficient amount of the curing agents. As the solvent, alcohols such as ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, esters such as ethyl acetate, amides such as dimethylformamide,
Examples thereof include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-hexane, halogenated hydrocarbons such as chloroform, and mixtures thereof.

The amount ratio of the curing agent and the solvent in the solution may be in a range such that, when the solution is applied, the curing agent exerts a sufficient effect and does not have a high viscosity such that workability is adversely affected. It is not particularly limited. Generally, the weight ratio of the curing agent to the solvent 1 is preferably about 0.1 to 2.

The coating amount of the curing agent depends on its type and the type of matrix resin of the prepreg, but it is generally about 10 to 200 g, preferably about 20 to 100 g per 1 m ² of the prepreg.

The present invention is mainly characterized in that a solution containing a curing agent and a solvent is applied to the prepreg. However, in order to cure the prepreg more quickly, a curing accelerator, a room temperature curable adhesive, etc. are added to the solution. You may make it contain. In addition to a solution containing a curing agent and a solvent, a solution containing a curing accelerator and a solvent, a solution containing a room temperature curing adhesive and a solvent, a solution containing a curing accelerator, a room temperature curing adhesive and a solvent, etc. are separately provided. You may prepare and apply to a prepreg.

The curing accelerator used in the present invention is selected according to the kind of the resin, and a Lewis acid, a phenol, an organic phosphine compound such as triphenylphosphine, a carboxylic acid compound such as salicylic acid, and a third compound such as benzyldimethylamine. Examples include amines and salts thereof, polymercaptans and imidazoles.

The room temperature curing type adhesive is a combination of a room temperature curing type resin and a curing agent, and the resin as the main component is bisphenol A type epoxy resin, bisphenol F type epoxy resin, glycidyl ether type epoxy resin. Preferred examples include epoxy resins such as glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, heterocyclic epoxy resin and halogenated epoxy resin. Examples of the curing agent include the curing agents described above.

The compounding amounts of the curing agent, the curing accelerator and the room temperature curing type adhesive are not particularly limited as they depend on their kinds, but generally, in a weight ratio, to the curing agent 1. It is preferable to use 0.001 to 2 for the curing accelerator and 0.1 to 20 for the room temperature curing adhesive.

The viscosity of the solution applied to the prepreg is about 2
~ 6000 cp, more preferably about 100-4000 c
p. Within the above range, the active ingredients such as the curing agent, the curing accelerator, and the room temperature curing adhesive in the solution are rapidly migrated into the prepreg, the workability is good, and the prepreg is cured in a short time. The solution viscosity may be adjusted by adding finely powdered silica, carbon black or the like to the solution.

The prepreg after application of the solution is dried more quickly by forced hot air drying, but may be naturally dried. For example, even under a low temperature of 10 ° C. or less, it is sufficiently cured in about 30 days.

[0030]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 A cylindrical concrete structure was preliminarily removed by subjecting it to a base treatment for smoothing the surface. A prepreg (trade name Hy25, manufactured by Kasei Fiberride Co., Ltd., fiber amount 250 g / m ² , resin content 35% by weight) in which carbon fibers aligned in one direction are impregnated with a 120 ° C. curable resin The structure was attached with an adhesive so as to match the longitudinal direction. Next, 1 part by weight of acetone was added to 1 part by weight of a mercaptan-based curing agent (trade name: Capcure WR-6, manufactured by Yuka Shell Co., Ltd.) 1
Parts by weight, curing accelerator tris (dimethylaminomethyl) phenol (trade name Epicure 3010, Yuka Shell Co., Ltd.
A solution prepared by dissolving 0.5 part by weight thereof is applied to the surface of the prepreg with a brush so that the amount of the solution becomes about 100 g / m ² .
It was left to cure at 10 ° C. for 30 days. The prepreg was completely cured and had a very high reinforcing strength. A part of the cured prepreg was peeled off from the structure, and the tensile strength was measured and found to be 270 kg / mm ² .

Comparative Example 1 Room-temperature curing type epoxy resin compound (trade name EA9493
4, Toyoda Gosei Co., Ltd.) 1 part by weight of methyl ethyl ketone 1
The tensile strength of the prepreg was measured in the same manner as in Example 1 except that the liquid dissolved in 1 part by weight was applied to the prepreg used in Example 1 so that the prepreg had a weight of about 100 g / m ² and was left for 35 days. .. The tensile strength was 205 kg / mm ² , and it was not sufficiently cured.

Comparative Example 2 Room-temperature curing adhesive (trade name: 910, manufactured by Dainippon Color Materials Co., Ltd.)
3 parts by weight of solvent (trade name: Eposinner, Dainippon Color Materials Co., Ltd.)
Except that the liquid dissolved in 2 parts by weight was applied to the prepreg used in Example 1 at a rate of about 100 g / m ² .
The same operation as in Comparative Example 1 was performed to measure the tensile strength of the prepreg. The tensile strength was 195 kg / mm ² , and it was not sufficiently cured.

[0034]

Industrial Applicability According to the present invention, there is provided a method for reinforcing a structure which allows the prepreg to be cured in a short time with good workability regardless of environmental conditions, particularly temperature fluctuations. Further, according to the present invention, the structure is particularly suitable for outdoor work, and has good workability and can efficiently cure the prepreg in a short time even when the temperature fluctuates depending on the season, particularly at a low temperature of 10 ° C. or less in winter. A reinforcing method is provided. Further, according to the present invention, there is provided a reinforcing method suitable for reinforcing a structure such as a building, a tank, a chimney, a pier, and a floorboard.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location // B29K 105: 08 4F (72) Inventor Shoichi Sato 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryoh Kasei Co., Ltd., Research Institute (72) Inventor Katsuji Shimamoto 1000 Kamoshida-cho, Midori-ku, Yokohama, Kanagawa Sanryo Kasei Co., Ltd. Banchi Co., Ltd. Obayashi Technical Research Institute

Claims (1)

[Claims] 1. A surface of a structural element to be reinforced of a structure,
A method for reinforcing a structure, which comprises applying a prepreg, applying a solution containing a curing agent and a solvent to the prepreg, drying and curing the prepreg.