JPS6282173A - Method for repairing hydraulic reinforced concrete or inorganic material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for repairing reinforced concrete or hydraulic inorganic materials.

The present invention aims to improve the durability of reinforced concrete or hydraulic inorganic materials that prevent the deterioration of reinforced concrete or hydraulic inorganic materials that have deteriorated and become brittle or spalled, as well as suppress corrosion of reinforcing bars. The purpose is to provide an improved repair method for.

[Prior art]

Conventionally, the method for repairing deteriorated reinforced concrete or inorganic materials is to apply and impregnate the surface with a solution of a water-soluble silicate compound.

A method of coating the surface with cement paste has been proposed (Japanese Patent Publication No. 11988/1988).

[Problems that the invention aims to solve]

Foreign matter such as moisture, oil, dirt, dust, etc. adheres to the surface and cracks of deteriorated reinforced concrete or inorganic materials, so simply applying a water-soluble silicate compound solution to the surface will not damage the main body. It is difficult to penetrate, and the effect of inhibiting corrosion of internal reinforcing bars is not sufficient.

In addition, to compensate for the poor water resistance of the water-soluble silicate compound film formed on the surface, this film may be coated with cement paste, cement mortar, or a polymer dispersion added to these. Even if waterproofing is attempted, the alkaline component in the silicate reacts with CO2 in the atmosphere and produces salt, causing an efflorescence phenomenon.The adhesion of this salt layer is weak, so the coating material is removed from the repaired surface. It peels off or flakes off.

As described above, conventional methods have drawbacks in terms of durability.

[Means to solve the problem]

Therefore, the inventors of the present invention have conducted extensive research in order to improve these drawbacks, and have conducted extensive research to improve the surface layer of the surface layer before applying an aqueous solution of a water-soluble silicate compound (hereinafter referred to as chemical solution) to the surface to be repaired. Or the process of removing contained foreign substances,
The present inventors have also found that the repair effect can be improved by adding a step of removing the film of the coating on the surface of the repaired area after applying the chemical solution, and have completed the present invention.

That is, the present invention provides a method for repairing reinforced concrete or hydraulic inorganic material, which is characterized by combining the following steps when repairing reinforced concrete or hydraulic inorganic material.

(11) Step of removing the weakened portion of the object to be repaired and further removing foreign matter attached to or contained in the surface layer of the repaired portion [Step (l)].

(2) A step of applying an aqueous solution of a water-soluble silicate compound to the surface obtained in step il+ and allowing it to penetrate into the main body (
Step (21).

(3) Next, the step of removing the film of the coating material adhering to the surface treated in step (2) to expose the surface of the main body [step (3)].

(4) Step of coating and laminating the main body surface obtained by processing in step (3) with a waterproof coating material [Step +41), J
The gist is:

Hereinafter, the present invention will be described in detail.0 Embodiments of the present invention are as follows:
It consists of the following four steps.

[Step (l)] After removing weakened parts of reinforced concrete or hydraulic inorganic materials that have deteriorated or fallen off, and making V-cuts at cracked areas, the surface layer of the repaired area is washed and dried, and vacuum suction or compression is performed. Use gas blowing to remove foreign matter contained or attached to the surface of the repaired area.

(Step (2)) An aqueous solution of a water-soluble silicate compound to which an anticorrosive agent is added if necessary is applied to the surface obtained in step Tl, and is allowed to penetrate into the main body.

[Step (3)] The film of the coating material adhering to the surface treated in step (2) is removed to expose the main body surface.

[Step (4)] A suitable support material is applied as necessary depending on the thickness of the coating material to be laminated on the main body surface obtained by the treatment in step (3), and a waterproof coating material is coated and laminated.

The first feature of the method of the present invention is that foreign matter attached to or contained in the surface layer is removed before applying the chemical solution to the surface to be repaired.

Generally, many years have passed since the object to be repaired was constructed or manufactured, so foreign substances such as moisture, dust, sand, colloids, oil, and salt may adhere to the surface or get stuck inside the cracks. ing. For this reason, even if a chemical solution is simply applied to the surface and attempts to penetrate the inside of the main body, it takes a long time or the chemical solution does not penetrate.

By removing these foreign substances, the penetration depth of the chemical solution into the interior of the body of the object to be repaired is increased, and the anticorrosion effect of the reinforcing bars inside the body is maintained and the progress of deterioration of the object is prevented.

The second feature of the method of the present invention is that after applying the chemical solution, the film of the coating material on the surface of the repaired part is removed to expose the main body surface.

The coating formed when the chemical solution applied to the surface of the repair target dries has low water resistance, and the alkaline component in the silicate compound contained in the chemical solution reacts with carbon dioxide gas in the atmosphere, causing water-soluble It changes to carbonate and produces an efflorescence component, leading to a decrease in adhesive strength, so even if a waterproof coating is applied over a dried and cured coating of the chemical solution, it will peel off between the eyebrows and peel off.

By removing the film of the coating material on the surface of the repaired part and laminating the coating material on the exposed main body surface, it is possible to prevent the IR1 from peeling off or peeling off from the repaired surface of the coating material.

The method of the present invention incorporating the above features can significantly improve the durability of repair objects.

The reinforced concrete that is subject to the repair method of the present invention is:
In general, it includes structures in the civil engineering and construction field and secondary concrete products, and hydraulic amorphous materials include ordinary Portland cement, early strength cement, ultra early strength cement, moderate heat Portland cement, sulfate-resistant Portland cement, Portland cement such as white Portland cement, mixed cement such as blast furnace cement, silica cement, fly ash cement, alumina cement, ultra-fast hardening cement (rapid hardening cement, jet cement), colloidal cement, cement pulverized to several micrometers, expansion The main raw materials are one or more types of special cements such as cement, calcium silicate, gypsum hemihydrate, anhydrite, lime, and fly ash slag, and if necessary, various aggregates and cement admixtures are added, and water is added. This refers to the product that is kneaded and then hardened.

Hereinafter, the four steps of the present invention will be sequentially explained.

[Step (l)] Foreign matter removal step; This step is a step in which the chemical solution applied to the surface to be repaired in the next step (2) is allowed to penetrate deeper into the main body of the object to be repaired.

In this step, first, weakened parts of the surface or body of the object to be repaired are removed, and cracks are treated with V-cuffs. These treatments can be performed by wire brushing, sandblasting, sandblasting, etc.

Next, the treated surface is washed with water, a cleaning agent, a solvent, etc., then air dried or hot air dried, and any foreign matter adhering to it is removed by suctioning under reduced pressure or blowing compressed air. .

As the above-mentioned cleaning agent and solvent, those commonly used for removing oil and the like can be used.

[Step (2)] Chemical application and penetration step; In this step, an aqueous solution of a water-soluble silicate compound is applied to the repaired part in order to make the neutralized part of the repair object alkaline and suppress corrosion of the reinforcing steel. and let it penetrate into the main body.

The water-soluble silicate compound used in the present invention has the general formula:
It refers to a single silicate salt represented by MzO-nsiO□ or a mixture thereof.

In the above general formula, the gate represents an alkali metal element such as Li, Na, or Cs, specifically lithium silicate,
Examples include alkali metal silicates such as potassium silicate, sodium silicate, and cesium silicate. Molar ratio (SiJ/MzO): The value of n is in the range of 1 to 100, preferably 1 to 10.

In addition, compounds in which H can be represented as an ammonium component in the above general formula can also be used, and examples of such compounds include methylamine silicate, ethylamine silicate, dimethylamine silicate, diisopropyl silicate acid, trimethylamine silicate, Examples include silicic acid amines such as triethanolamine silicate; quaternary ammonium silicates such as ammonium silicate, monomethyltriethanolammonium silicate, and tetraethanolammonium silicate.

The water-soluble silicate compound used in the present invention has the general formula: Si(OR)4. Tetraalkoxysilanes (silicate ester R
), and specific examples include tetramethoxysilane (methyl silicate) and tetraethoxysilane (ethyl silicate).

In order to improve the water resistance of the water-soluble silicate compound after drying and curing, a curing agent such as an organic ester or an aldehyde may be added to the chemical solution within a range that does not adversely affect workability and permeability.

The concentration of the silicate compound in the chemical solution is not particularly limited, but it is preferably used in the range of 10 to 30% by weight; if the concentration is lower than this range, the effect will be small, and if the concentration is higher, the permeability will decrease.

A silicate-based compound alone has a small corrosion-preventing effect on reinforcing steel. In order to compensate for this, an anticorrosive agent can be added to the chemical solution in the method of the present invention.

Inorganic anticorrosive agents used in the present invention include one or two alkali metal salts such as sodium and potassium of acids such as chromic acid, nitrous acid, phosphoric acid, polyphosphoric acid, molybdic acid, and tungstic acid. The above can be used.

Further, examples of the organic type include commonly used amine type, thiourea type, mercaptan type and the like.

The amount of the anticorrosive agent to be used is not particularly limited, but it may be added in an amount of about 10 to 1000 ppm based on the chemical marsupial.

[Step (3)] Chemical film removal step: In this step, a chemical is applied to the surface of the repaired part and permeated into the interior of the main body, and then the chemical that adheres to the surface and its dry hardened film are removed, and the object to be repaired is removed. expose the surface.

The chemical solution adhering to the surface of the repaired part is wiped off or washed away, and the cured chemical solution is scraped off to the extent that the surface of the object to be repaired is exposed.

[Step (4)] Waterproof coating material lamination step: In this step, in order to prevent the elution of the drug applied and penetrated in step (2) and to continue its effect, the step (
A waterproof covering material is coated and laminated on the surface of the object to be repaired which has been exposed through the process of 3).

The coating material of the present invention includes organic adhesive, cement paste, cement mortar, polymer cement paste,
One or more of polymer cement mortar, resin concrete, etc. can be used.

Examples of the organic adhesive of the present invention include polymers for coating or mixing cement concrete, liquid or paste resins for resin concrete, and monomers for impregnating concrete, which are commonly used in the field of civil engineering and construction.

Polymers for cement concrete include aqueous polymer dispersions, such as natural rubber Latinx;
Styrene-butadiene rubber (SBR).

Nitrile-butadiene rubber (NBR), chloroprene.

Synthetic rubber latex such as methyl methacrylate-butadiene rubber; synthetic resin emulsions such as acrylic acid ester type, vinyl acetate type, ethylene-vinyl acetate copolymer type, vinylidene chloride-vinyl chloride copolymer type, etc. can be used.

As the liquid or paste resin for resin concrete, various resins such as unsaturated polyester, epoxy, polyurethane, tar epoxy, tar urethane, epoxy asphalt, and rubber asphalt can be used.

Monomers for concrete impregnation include methacrylic acid ester, styrene, acrylonitrile, and styrene.
Examples include acrylonitrile, vinyl chloride, vinyl acetate, trimethylolpropane trimethacrylate, diallyl phthalate, and epoxystyrene.

These usages may be carried out according to commonly used methods.

Cement paste, cement mortar used in the present invention,
The cement used in polymer cement paste, polymer cement mortar, etc. can be used singly or in combination of two or more of the above-mentioned Portland cements, mixed cements, and special cements.

Cement paste is made by adding an appropriate amount of water to cement and kneading it into a paste.Cement mortar is a mixture of the above cement and one or more of river sand, sea sand, silica sand, lightweight aggregate, gravel, etc. It is a product obtained by appropriately blending and kneading with water.

Further, in order to improve waterproofness and adhesiveness of cement paste or cement mortar, the aqueous polymer dispersion described above is added and kneaded, which are referred to as polymer cement paste or polymer cement mortar.

The amount of this aqueous polymer dispersion added varies depending on the type and is not particularly limited, but it is usually mixed in an amount equivalent to 2.5 to 25% by weight of solids based on the amount of cement.

Furthermore, a cement admixture or the like can be used in combination with these.

Examples of resin concrete include polycondensation polymer materials such as polyester and epoxy, or polyaddition polymer materials such as polyurethane mixed with fillers such as calcium carbonate and silica sand. can.

A fibrous material can be added to the waterproof coating material of the present invention for the purpose of preventing cracking, increasing strength, preventing peeling, etc.

Examples of the fibrous material used in the present invention include steel fibers, glass fibers, alkali-resistant synthetic fibers such as vinylon, nylon, and polyester, carbon fibers, and asbestos, which are commonly used for cement addition.

The thickness, length, and amount of these fibrous materials to be used may be within a commonly used range and are not particularly limited.

The thickness of the waterproof coating layered in the method of the present invention is not limited.

When the laminated thickness of the sheathing material becomes large, the gravitational force due to the increase in the sheathing material's own weight exceeds the adhesion of the sheathing material to the repaired surface, so the laminated sheathing material will fail if no assistance is provided to support the sheathing material. During the curing process, the coating material may sag or partially lift from the repaired surface, which reduces the adhesion strength of the coating material to the wall surface.

In order to prevent such a phenomenon from occurring, when a thick layer of coating material is to be applied, it is advisable to provide a suitable support material to support the coating material on the repaired surface.

If the thickness of the covering material needs to be approximately 2 cm or more, it is preferable to laminate the covering material after fixing the repaired surface with a lath or net before applying the covering material.

Examples of the lath to be used include metal lath, replus, and wire lath, and the net is preferably made of alkali-resistant synthetic resin such as polyvinyl chloride, polyethylene, nylon, and polypropylene.

Furthermore, if the repaired part is a top plate or if the thickness of the covering material needs to be further increased, it is preferable to assemble and fix the repaired part using a support plate, then fill it with the covering material and harden it.

After this treatment is completed, the surface is finished with paint or other suitable exterior material, if necessary.

〔Effect of the invention〕

The present invention has the following effects.

1) It is possible to increase the penetration depth of the chemical solution applied to the repaired surface of deteriorated reinforced concrete or hydraulic inorganic material into the main body, thereby improving the anticorrosion effect of the internal reinforcing bars.

2) Increase the adhesion strength of the waterproof coating material to the repaired surface, which is layered on the repaired surface impregnated with the chemical solution, eliminate "sagging" or floating of the coating material, and prevent the coating material from peeling off from the repaired surface. can do.

3) This allows reinforced concrete or hydraulic heat @
The durability of the material can be improved.

〔Example〕

The present invention will be explained below with reference to Examples, Reference Examples, and Comparative Examples. Note that % indicates weight %.

Examples: 1 to 11, Reference examples = 1 to 2, Comparative examples: 1 to 11
We repaired the top plate of a concrete slab that had receded after pouring and had many cracks.

First, the surface or main body of the top plate was sandblasted, and cracks were cut. (Processing ■) Then, compressed air was blown onto the surface to remove adhering fine particles, and ■ fine particles clogging the cut area were removed by suction. C step).

Next, 5 oocc of the various chemical solutions shown in Tables 1 (1) and (2) per meter of the repaired surface treated in step (1) was applied to the main body. I made it la. [Step (21).

Next, the dried chemical coating formed on the coated surface was scraped off to expose the concrete surface. [Step +31).

Next, apply Table 1 (Table 1) to the exposed concrete surface.
It was coated with various waterproof coating materials shown in 2).

[Process +413°] For comparison, cases in which no treatment is performed in step (1) or cases in which treatment is not performed in step (3) are combined, and Table 1 is combined with reference examples or examples as comparative examples.
Shown in (1) and (2).

Method for evaluating results; Penetration depth of chemical solution: A sample was taken from the repaired area one day after construction, and the chemical components used were analyzed to determine the penetration depth of the chemical solution.

・Adhesive strength of coating material: Measured using a Kenken type flexible tensile test device one year after laminating the coating material.

・Corrosion prevention effect: One year after construction, the reinforcing bars were exposed and judged based on their appearance as follows.

A: No change was observed.

B: Slight discoloration is observed locally.

C...Corrosion is observed 6 D: Considerable corrosion is observed.

The following can be seen from Table 1 (1).

When left alone with treatment (■), the reinforcing bars developed rust and considerable corrosion was observed. (Comparative example = 1).

In step [11, only process ■ is performed, and step (2)
Even if the chemical solution is applied with
Corrosion prevention effect is not sufficient. (Comparative example: 2).

By the treatment in step (11), the penetration depth of the chemical solution into the main body becomes thick (and the anticorrosive effect becomes better. Also, by adding an anticorrosive agent to the chemical solution, the anticorrosive effect is further improved. (Reference examples = 1 to 1) 2).

Furthermore, according to Table 1 (2), according to the method of the present invention, the penetration depth of the chemical solution into the main body is large, the anticorrosion effect can be enhanced, and the adhesive strength of the coating material to the repaired surface can be increased. can. (Examples = 1 to 11).

On the other hand, when only the treatment (2) was performed in step +11 and the chemical solution was applied in step (2), the penetration depth of the chemical solution into the main body was small, and the anticorrosion effect was not sufficient. (Comparative example: 3, 5, 6.8).

Furthermore, when the coating material is laminated without performing the treatment in step (3), the adhesive strength of the coating material to the repaired surface is low and the durability is poor. (Comparative example: 4, 5.7, 8, 9.lO+11)
.

When the laminated thickness of the sheathing material becomes large, the gravitational force due to the increased weight of the sheathing material exceeds the adhesion force of the sheathing material to the repaired surface. The coating material was lifted off the repaired surface, and variations in adhesive strength of the coating material to the repaired surface were observed. (Example: 6,
8.10).

Even when the laminated thickness of the coating material was increased, stable adhesive strength was obtained by applying an appropriate support material. (Example Near, 9.11).

Example: 12 The exterior wall surface of an 8-story RC building, which had been constructed 20 years after its construction, had deteriorated due to salt damage was repaired.

The outer wall surface was sandblasted, the cracks were cut out, and the fine particles adhering to the surface and inside the cracks were removed by suction under reduced pressure.

Furthermore, since the outer wall contained 0.5 to 2.3% of NaCl, the wall surface was washed with water to reduce the NaCl content to about 1710.

Next, after naturally drying the wall surface treated as above, a 10% aqueous solution of lithium silicate of 5iOz/Li, 0 molar ratio: 3.7 was applied five times, and a 15% aqueous solution was repeatedly applied three times. Infiltrated.

After drying, the lithium silicate film adhering to the coated surface was scraped off to expose the concrete surface.

SB as a waterproof coating on exposed concrete surfaces
500cc of R latex aqueous solution (solid content: 20χ)
/ %lfi, and a cement paste containing SBR latex in an amount equivalent to 10% solid content based on the rapid hardening cement was laminated to a thickness of 3 to 6 layers. Next, it was finished by covering it with an acrylic rubber waterproof exterior material.

When inspected five years after the repair, no abnormalities were found.

For comparison, in a test location where the coating material was laminated without scraping off the lithium silicate film, the coating material was lifted from the construction surface, indicating a decrease in adhesive strength.

Claims (1)

[Scope of Claims] A method for repairing reinforced concrete or hydraulic inorganic material, characterized by combining the following steps when repairing reinforced concrete or hydraulic inorganic material. (1) Step of removing the weakened portion of the object to be repaired and further removing foreign matter attached to or contained in the surface layer of the repaired portion [Step (1)]. (2) A step of applying an aqueous solution of a water-soluble silicate compound to the surface obtained in step (1) and allowing it to penetrate into the main body [step (2)]. (3) Next, the step of removing the film of the coating material adhering to the surface treated in step (2) to expose the surface of the main body [step (3)]. (4) Step (4) of covering and laminating the main body surface obtained by the treatment of step (3) with a waterproof coating material.