JP3207105B2 - Repair method of concrete structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for easily repairing (including reinforcing) a concrete structure which is excellent in the removability of a paint film existing on the surface of a previously painted concrete structure.
On how to do.

[0002]

2. Description of the Related Art Conventionally, as a method of repairing a concrete structure, a method of bonding a steel plate to a concrete structure has been adopted, and an adhesive is injected between the concrete structure and the steel plate as an object to be injected. A method of injecting an adhesive that can be integrated into a single piece has been studied. Also, in recent years, concrete structures have been painted, and when repairing by a conventional method, a method of peeling the coating film for the purpose of finding cracks hidden behind the coating film is considered. It has become. Conventionally, various types of release agents have been proposed for use in removing a paint film or the like. Among them, those containing a halogenated hydrocarbon such as methylene chloride as a main solvent are widely used because they are excellent in permeability and swelling property to a coating film and are nonflammable. For example, the most common coating film remover is methylene chloride as a main solvent, a cosolvent such as methanol, a peeling accelerator such as amines, an evaporation inhibitor such as paraffin wax, and a water-soluble agent such as methylcellulose and carboxycellulose. It is prepared by adding a thickener of a conductive polymer or the like. Such a release agent is applied onto a coating film to be removed with a brush or the like, left for a while, and then the swollen coating film is scraped off with a trowel or a scraper. However, the scraping operation is a very laborious and complicated operation. Further, in the scraping operation, methylene chloride remaining without volatilization adheres to a finger of an operator and irritates the skin, etc., and there is a problem that an operator has more chances to inhale a solvent. Was. In addition, in order to perform repainting after the coating film is peeled off, there is also a problem that it is necessary to remove paraffin wax or the like remaining on the peeled surface by water washing or other means in order to improve the wetting of the paint.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for repairing a concrete structure which is excellent in workability, safety and environmental protection.

[0004]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies and as a result, applied a specific release agent to the surface of a concrete structure, placed a sheet thereon, and placed the sheet on the concrete structure. It has been found that by peeling off, the coating film on the surface of the concrete structure can be substantially completely removed via the release agent, and the present invention has been accomplished. That is, the present invention relates to the following inventions. 1. A method for repairing a concrete structure having a coating film on its surface, comprising an alkaline compound (A) comprising 1 to 50% by weight of an alkali metal compound (i) and 50 to 99% by weight of an alkaline earth metal compound (ii). After applying a release agent composition comprising the adhesive (B) and the solvent (C), a sheet is placed thereon, and the sheet is peeled off, whereby the coating film on the surface of the concrete structure is peeled off. 1. A method for repairing a concrete structure, which comprises injecting a resin solution for repair into cracks on the surface of the concrete structure. On the surface of the concrete structure in which the resin liquid has been injected into the crack, a metal sheet having an injection hole is further fixed away from the surface of the concrete structure, and between the surface of the concrete structure and the metal sheet. 2. The method for repairing a concrete structure according to claim 1, wherein a resin solution for repair is injected from the injection hole. The method for repairing a concrete structure according to claim 1, wherein a formwork is installed on an outer peripheral portion of the concrete structure in which the resin liquid is injected into cracks, and after reinforcing with a reinforcing material, concrete is poured. And 4. A formwork is installed on the outer periphery of the concrete structure in which the resin solution is injected between the surface of the concrete structure and the metal sheet, and after reinforcing with a reinforcing material, concrete is poured. The method for repairing a concrete structure according to claim 2.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Alkaline compound (A) used in the present invention
Consists of an alkali metal compound (i) and an alkaline earth metal compound (ii). Examples of the alkali metal compound (i) include an alkali metal oxide, an alkali metal hydroxide, and an alkali metal carbonate, and specifically, sodium oxide, potassium oxide, sodium hydroxide, potassium hydroxide, and sodium carbonate. , Potassium carbonate and the like.
Sodium hydroxide and potassium hydroxide are preferably used as the alkali metal compound (i). Examples of the alkaline earth metal compound (ii) include an alkaline earth metal oxide, an alkaline earth metal hydroxide and an alkaline earth metal carbonate, and specifically, magnesium oxide, calcium oxide, strontium oxide, Examples include barium oxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate. As the alkaline earth metal compound (ii), magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide are preferably used.

The alkali metal compound (i) is used in an amount of 1 to 50% by weight, based on the total weight of the alkali metal compound (i) and the alkaline earth metal compound (ii), and is therefore ii) is used at 99-50% by weight, based on this total weight. Preferably, the alkali metal compound (i) is used at 5 to 15% by weight, while the alkaline earth metal compound (ii) is 95% by weight.
Used at ~ 85% by weight. Within this use range,
Excellent peelability of the coating film is obtained. Examples of the thickener (B) used in the present invention include polysaccharides, cellulose, cellulose derivatives, natural rubber, recycled rubber, synthetic rubber, rosin, ester gum, petroleum resin, xylene resin, phenol resin, terpene resin, Silicone resin, acrylic resin,
Examples include vinyl resins or copolymer resins thereof, and liquid polybutene, liquid isobutylene, petrolatum, tar, and lanolin. Specifically, starch, glycogen, caronine, laminaran, dextran, inulin,
Leban, elegans mannan, xylan of rice straw, pectic acid, alginic acid, lichenin, guaran, konjac mannan, heparin, chondroitin sulfate, hyaluronic acid, meskit gum, gatch gum, gum arabic,
Mucilage such as musk of musk, gum, bacterial polysaccharide, acetyl cellulose, cellulose propionate, cellulose butyrate, nitrocellulose, cellulose sulfate, cellulose phosphate, cellulose acetate butyrate, cellulose nitrate acetate,
Examples include cellulose esters such as viscose, and cellulose ethers such as methylcellulose, ethylcellulose, benzylcellulose, tritylcellulose, carboxymethylcellulose, cyanethylcellulose, carboxyethylcellulose, aminoethylcellulose, oxyethylcellulose, and hydroxyethylcellulose. These thickeners can be used alone or as a mixture of two or more.

As the solvent (C) used in the present invention, a chlorinated solvent represented by methylene chloride, an alcohol such as methanol, ethanol or polyvinyl alcohol;
Inorganic liquids such as water and aqueous ammonium hydroxide are exemplified. These solvents can be used alone or as a mixture of two or more. The release agent composition used in the present invention contains the above-mentioned alkaline compound (A), thickener (B) and solvent (C) as essential components. In this case, the alkaline compound (A) is usually 1 to 80% by weight, preferably 1 to 80% by weight, based on the weight of the release agent composition comprising the alkaline compound (A), the thickener (B) and the solvent.
2 to 50% by weight. The thickener (B) is used in an amount of usually 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the weight of the release agent composition. It can be dissolved in a solvent such as water or alcohol to form a gel, which can be incorporated into the composition. By using within this range, sagging of the applied composition can be prevented, uniform application can be achieved, and effective peeling can be achieved. The solvent (C) is used in an amount of 10 to 98.5% by weight, preferably 40 to 90% by weight, based on the weight of the release agent composition.
Used in quantity. Within this range, it acts synergistically with the alkaline compound to swell and dissolve the coating film, and the penetration of the solvent into the substrate reduces the adhesion of the coating film, resulting in peeling of the coating film.

[0008] The release agent composition used in the present invention may optionally contain other optional additives. For example, as other additives, an evaporation inhibitor represented by paraffin, a nonionic or anionic surfactant, a sodium dialkyl succinate, a film penetrant such as sodium lauryl sulfate, magnesium sulfate whisker, Potassium titanate whisker, aluminum borate whisker, calcium sulfate whisker, nylon, rock wool, fibrous filler such as pulp fiber, various amines,
Examples include a corrosion inhibitor, a desiccant, a plasticizer, and a coloring agent. These optional components can be appropriately blended and used. In the present invention, after applying the release agent composition, the sheet is placed thereon. The release agent composition can be applied by various methods such as spray coating and roll coating. Preferably, the sheet is placed early, preferably immediately, in an undried state after the release agent composition has been applied. As a method of installing the sheet, water may be added to the sheet and the sheet may be attached to the release agent composition, or the sheet may be fixed by a fixture or the like. If the seat is lightweight, the seat can be easily installed by installing it after soaking it in water. On the other hand, if the sheet is heavy, it can be installed by fixing it to the surface of the concrete structure with a rope, wire, or the like, depending on the location.

In the present invention, when the release agent composition is applied to a coating film existing on the surface of a concrete structure,
The components in the release agent composition, in particular, the alkaline compound acts on the coating film, decomposes the coating film, swells in a solvent, partially dissolves, and even in a coating state in which swelling has occurred, when peeled, Along with the release agent composition, the underlying coating film that has undergone decomposition is also simultaneously released. Moreover, when this release agent composition is used, the coating film is almost completely removed.
Further, the sheet prevents the solvent component in the composition from evaporating, and can effectively maintain the peeling action for a long time. The sheet provided on the release agent composition is usually 1 to
After holding for 5 days, preferably 1 to 3 days, and peeling,
The coating film can be removed neatly. As the sheet to be used, for example, a sheet made of felt, polypropylene, polyalkylene, polyamide, polyester, polyvinyl halide, cotton, wool, fur, paper, cloth plastic, or the like can be used. The resin solution for reinforcement used in the present invention, or the resin solution for reinforcement is not particularly limited, and is particularly limited as long as it is a resin solution conventionally used in repairing or reinforcing concrete structures. Can be used without. For example, a thermosetting resin such as a low-viscosity epoxy resin, polyester, or polyurethane, or a conventionally known injection agent such as a non-shrink mortar can be used.

The metal sheet used in the present invention is not particularly limited as long as it is conventionally used for repairing concrete structures and the like. Examples of such a metal sheet include a thin plate and a galvanized steel plate. The size, shape, and the like of the injection hole provided in the metal sheet can be used as long as it can inject a resin solution for reinforcement. In addition, the distance between the surface of the concrete structure and the metal sheet varies depending on the location to be used, the viscosity of the reinforcing resin solution, and the like. If it is a system material, it is 3 to 10 cm. However, if the distance is smaller than this, the strength is insufficient, and if the distance is larger, the expensive resin is consumed multiple times, which is not preferable. The mold is not particularly limited as long as it is conventionally used, and various molds, for example, wood, plywood, instrument panel, steel plate (metal foam) and the like can be used. Examples of the reinforcing material used in the present invention include a reinforcing bar, a steel frame, and a mortar, but are not particularly limited, and various reinforcing materials can be used.

The concrete to be cast used in the present invention is:
Consists of cement, water, supplements and admixtures. As the cement, for example, Portland cement, white cement, and ultra-high-speed cement, alumina cement or the like as a special cement are used. As the aggregate, natural aggregates such as river sand and mountain sand, and artificial aggregates such as crushed sand and blast furnace slag aggregate are used. Examples of the admixture include an AE agent, a water reducing agent, a hardening accelerator such as an AE water reducer, an admixture with a rust inhibitor and the like, fly ash, siliceous fine powder, a synthetic rubber polymer, a colorant,
Admixtures such as thickeners can be used. These can be used in various combinations without particular limitation. As a method of repairing a concrete structure of the present invention, (I) after injecting a resin solution into a crack portion,
(II) After fixing the metal sheet and then injecting the resin solution, (III) after casting concrete, it is possible to further apply a coating.

[0012]

The present invention will be described in more detail with reference to the following examples. <Coating film release agent composition> 5 parts by weight of sodium hydroxide; 15 parts by weight of calcium hydroxide; 1 part by weight of hydroxyethyl cellulose; 29 parts by weight of water; 40 parts by weight of methylene chloride; and 10 parts by weight of petrolatum are mixed and stirred. A cloudy paste-like coating film release agent composition was produced. Example 1 The above-mentioned composition for peeling off a coating film was spray-coated on a concrete wall having a coating film on a cracked surface, and a polypropylene sheet wetted with water was attached thereto. After 24 hours, the polypropylene sheet was peeled off. Then, the coating film on the concrete wall surface was peeled off. At this time, the coating film adhered to the concrete wall was completely removed. Next, the surface was treated with a wire brush along the width of the cracks found after the coating film was removed, and the cracked portion was treated with a resin guard grout #
Seal with 100 (Epoxy resin injection material manufactured by Dainippon Paint Co., Ltd.), attach the injection port to the cracked part, inject Regigrad Clout K (epoxy resin adhesive manufactured by Dainippon Paint Co., Ltd.) into the cracked part, The inlet was removed and groundwork was applied. Example 2 Except for changing the polypropylene sheet to a polyamide sheet, the coating on the concrete wall was removed in the same manner as in Example 1. As a result, the coating film was almost completely removed. Then, on the surface of the concrete wall subjected to the groundwork treatment in the same manner as in Example 1, a spacer for securing the thickness is applied to the end face, a galvanized steel sheet having an injection hole is attached, and then an anchor is driven and welded, After welding,
From the injection hole, Regid Grout S (Dainippon Paint Co., Ltd.)
Epoxy resin injection material) is injected, and after the injection, the surface of the steel plate is coated with Epool # 30 (epoxy resin paint manufactured by Dainippon Paint Co., Ltd.), and after drying, V Freon # 100 (fluorine resin paint manufactured by Dainippon Paint Co., Ltd.) Was painted. As a result, an excellent repair effect was obtained. Example 3 A formwork was provided on the outer periphery of a concrete wall which had been subjected to groundwork in the same manner as in Example 1, reinforced with reinforcing steel, backfilled with mortar, 100 parts of Portland cement, 200 parts of sand, crushed stone (10 to 15 mm). ) Fresh concrete consisting of 300 parts and 50 parts of water was poured. As a result, an excellent repair effect was obtained. Example 4 A steel plate was welded in the same manner as in Example 2 except that the coating was not performed. Then, a formwork was provided on the outer periphery of the concrete wall to which the steel plate was fixed, reinforced with reinforcing steel, and backfilled with mortar.
The same fresh concrete was poured. As a result, an excellent repair effect was obtained.

[0013]

According to the present invention, it is possible to easily and almost completely remove an old coating film, for which a suitable preventive measure has not been established conventionally, without human intervention. Therefore, it is easy to find cracks that are hidden by the coating film and cannot be seen. Further, in the case of peeling of the old coating film, a step of scraping with a trowel or a scraper or an operation such as washing with water to remove residual paraffin wax or the like was necessary.In the present invention, such a complicated operation is required. It becomes unnecessary, and the work efficiency is greatly improved. Therefore, the method of the present invention is a very excellent method for repairing and reinforcing various concrete structures and secondary concrete products.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E04G 23/02

Claims (4)

(57) [Claims] 1. A method for repairing a concrete structure having a coating film on its surface, comprising: an alkali metal compound (i)
0% by weight and alkaline earth metal compound (ii) 50-99
Weight% alkaline compound (A), thickener (B)
And a solvent (C), a release agent composition is applied, a sheet is placed thereon, and the sheet is peeled off to peel off the coating film on the surface of the concrete structure, and to form a crack on the surface of the concrete structure. A method for repairing a concrete structure, characterized by injecting a resin solution for repair into a concrete structure. 2. A concrete sheet having an injection hole is further fixed on a surface of a concrete structure in which the resin liquid has been injected into cracks, separated from the surface of the concrete structure. Between the sheet,
The method for repairing a concrete structure according to claim 1, wherein a resin solution for repair is injected from the injection hole. 3. The concrete structure according to claim 1, wherein a formwork is installed on an outer peripheral portion of the concrete structure in which the resin liquid has been injected into cracks, reinforced with a reinforcing material, and then concrete is poured. How to repair things. 4. A formwork is installed on the outer periphery of the concrete structure in which the resin solution has been injected between the surface of the concrete structure and the metal sheet, and reinforced with a reinforcing material.
3. The method for repairing a concrete structure according to claim 2, wherein concrete is cast.