JP6641106B2 - Repair material and repair method for concrete structures - Google Patents

Description

  The present invention relates to a repair material used for preventing a concrete structure from peeling off and a repair method using the repair material.

  Since concrete structures have the advantages of high strength, excellent workability, and low cost, many concrete structures have been made in Japan mainly during the high growth period. Concrete buildings have excellent durability, but carbon dioxide in the atmosphere penetrates with moisture over many years of use, causing neutralization, and chloride ions contained in sea breeze and antifreeze droplets penetrate As a result, cracking may occur due to corrosion and expansion. Concrete pieces may come off from such cracks as a starting point or due to freezing of water soaked in concrete. Peeling of concrete shards can be fatal, particularly when the underside of the concrete structure is used as a road.

  As an attempt to prevent such concrete peeling, Patent Literature 1 discloses a technique in which a crack is formed by drilling a cracked portion to form a gap and an adhesive such as an epoxy resin is injected into the gap. . As another solution, Patent Literature 2 discloses a technique for preventing peeling by bonding a multiaxial fiber woven fabric to a surface where concrete is likely to come off.

Japanese Patent No. 5074118 JP 2013-01146 A

  However, the method of Patent Document 1 has problems such as that the peeling easily proceeds at the time of piercing of the concrete and that it is difficult to confirm whether the adhesive has reached the deepest part of the void. In addition, the method of Patent Document 2 requires complicated operations such as cleaning and drying of the concrete surface, application and drying of a primer, and coating and drying of an overcoat layer to prevent deterioration due to ultraviolet rays and oxidation.

  Furthermore, since all of the above-mentioned techniques are repair methods using a resin, there is a concern that when a fire occurs, the resin may expand and accelerate the exfoliation of concrete pieces or cause fire spread. Therefore, there is a problem that the techniques disclosed in Patent Documents 1 and 2 cannot be used for refractory structures.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a repair material and a repair method that are simple and can reliably prevent concrete from falling off.

  The present inventors, as a method of repairing the deterioration of the concrete structure, repair sheet based on the idea of bonding and fixing a sheet-like repair sheet containing a curable liquid composition as a main component to the concrete structure. Have a laminated structure, it has been found that it is possible to achieve both adhesion to a concrete structure, prevention of spalling, and fire resistance, and the present invention described below has been completed.

This application includes the following inventions.
(1) repair materials used for repairing existing concrete structures,
A curable liquid composition;
And a laminate in which at least two layers of sheet-like members are laminated,
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh-like sheet having a higher tensile strength than the second layer. Material for repairing concrete structures.
The repair material preferably comprises one or more of the following.
(2) a mixture of sodium silicate, potassium silicate and / or lithium silicate and a curing agent, and a laminate in which at least two sheet-like members are laminated;
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured to have a higher tensile strength than the second layer. ,
(3) A laminate of at least three layers of sheet-like members further provided with a third layer on the concrete structure side of the first layer, wherein the first layer has a higher tensile strength than the third layer. Is configured to be
(4) the third layer is composed of a nonwoven fabric;
(5) the second layer and the third layer are formed of a nonwoven fabric;
(6) the total thickness of the second layer and the third layer is 0.4 to 3.0 mm;
(7) the first layer is made of a long-fiber woven fabric;
(8) woven of the nonwoven fabric or long fibers are woven glass nonwoven or glass fiber containing ZrO ₂ of from 5 to 25 wt%,
(9) The basis weight of the first layer is 50 g / m ² or more, and is a biaxial woven fabric having an opening of 5 to 25 mm or a multiaxial woven fabric having an opening ratio equivalent to that of the biaxial woven fabric.
(10) The first layer and the second layer, or the first layer, the second layer, and the third layer are previously laminated and integrated,
(11) the curable liquid composition is a mixture of sodium silicate, potassium silicate and / or lithium silicate and a curing agent,
(12) The curing agent contains at least one selected from the group consisting of organic acid esters, dialdehydes, inorganic acid esters, organic acid metal salts, inorganic acid metal salts, metal oxides, and metal hydroxides.
(13) The curing agent contains at least one selected from the group consisting of acetate, carbonate, magnesium hydroxide, magnesium carbonate, calcium carbonate, calcium hydroxide, and aluminum silicate.
(14) The curing agent contains magnesium hydroxide or magnesium carbonate,
The magnesium hydroxide and the magnesium carbonate have a particle size of 0.5 to 20 μm,
(15) The curing agent is contained in an amount of 5 to 100 parts by mass with respect to 100 parts by mass of an aqueous solution of 40% by mass of sodium silicate, potassium silicate, lithium silicate or a mixture thereof.
(16) A repair method for repairing an existing concrete structure using the repair material for a concrete structure comprising the curable liquid composition and a laminate obtained by laminating at least two layers of sheet-like members,
An application and impregnation step of applying and impregnating the mixture to the laminate,
Affixing step of attaching the mixture to which the mixture has been applied and impregnated, to a target concrete structure,
A curing step of curing the laminate in which the mixture is applied and impregnated,
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh-like sheet having a higher tensile strength than the second layer. A method for repairing a concrete structure, characterized in that:
(17) A repair method for repairing an existing concrete structure using the repair material for a concrete structure, comprising the curable liquid composition and a laminate obtained by laminating at least two layers of sheet-like members,
An attaching step of attaching the laminate to a target concrete structure,
An application impregnation step of applying and impregnating the mixture to the laminate attached to a concrete structure,
A curing step of curing the laminate, the mixture being applied and impregnated,
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh-like sheet having a higher tensile strength than the second layer. A method for repairing a concrete structure, characterized in that:
Preferably, these repair methods include one or more of the following.
(18) An existing concrete structure using a repair material for a concrete structure comprising a mixture of sodium silicate, potassium silicate and / or lithium silicate and a curing agent, and a laminate in which at least two layers of sheet members are laminated. A repair method to repair,
When the first layer and the second layer from the concrete structure side, the first layer is configured to have a higher tensile strength than the second layer,
(19) The coating and impregnating step is performed by a mechanical device.

  The material for repairing concrete structures according to the present invention can more easily and reliably prevent concrete pieces from peeling off, and can be suitably used for fire-resistant structures.

It is a typical sectional view showing an example of the repair form of the concrete structure using the repair material (two-layer structure) of the concrete structure of the present invention. It is a typical sectional view showing an example of a repair form of a concrete structure using a repair material (three-layer structure) of the concrete structure of the present invention.

<Repair materials>
1 and 2 are schematic cross-sectional views showing a repair mode of a concrete structure using the repair material of the present invention. The repair material 5 of the present invention repairs the concrete structure 1 as shown in FIGS. 1 and 2, and comprises a curable liquid composition and a laminate in which at least two layers of sheet members are laminated. Is provided. The laminate and the curable liquid composition may be present separately, but it is preferable that the laminate be impregnated with the curable liquid composition during repair, as described later.

  The amount of the curable liquid composition impregnated in the laminate is not particularly limited, and the curable liquid composition is held uniformly throughout the laminate, and the entire laminate is strongly solidified by curing of the curable liquid composition. It is preferable to make adjustments so that they can be integrated with each other. For example, the mass ratio of the laminate to the curable liquid composition is preferably about 1: 4 to 1:12, and more preferably 1: 4 to 1:10.

As shown in FIG. 1, when the laminate is the first layer 2 and the second layer 3 from the concrete structure side, the first layer 2 is configured to have a higher tensile strength than the second layer 3. ing. As shown in FIG. 2, when the third layer 4, the first layer 2, and the second layer 3 are arranged from the concrete structure side, the first layer 2 has a higher tensile strength than the second layer 3. And the tensile strength is higher than that of the third layer 4.
By attaching the repair material 5 of the present invention to the concrete structure 1 as shown in FIGS. 1 and 2, the curable liquid composition in the repair material is applied and impregnated on the surface of the concrete structure 1, and the mixture is impregnated. The concrete structure 1 can be repaired more easily and reliably by hardening or combining with the concrete structure.

(Laminate)
The laminate constituting the repair material 5 is a laminate in which two or more sheet-like members are laminated. The laminate is arranged with the first layer 2 and the second layer 3 in order from the side in contact with the concrete structure 1. When the laminate has three or more layers, the third layer 4, the first layer 2, and the second layer 3 are arranged in this order from the concrete structure side.

Here, each sheet-like member constituting the laminate has a predetermined thickness and may have an area capable of covering all or a part of the concrete structure to be repaired, such as glass, plastic, cloth, It can be formed of various materials such as paper, metal, and composite materials thereof. Especially, since concrete itself is nonflammable, it is similarly preferable to be comprised from a nonflammable material. Glass fibers are examples of non-combustible materials. In addition, such a material preferably further contains 5% by mass or more and 25% by mass or less of ZrO2, and more preferably contains 8% by mass or more and 20% by mass or less of ZrO2 in order to prevent alkali corrosion by concrete. More preferably, it contains 10% by mass or more and 18% by mass or less of ZrO ₂ . The strength of the repair material can be maintained by preventing alkali corrosion of the glass fiber.

  Glass fibers are mainly surface-treated, but from the viewpoint of improving the adhesion with the curable liquid composition, polyvinyl alcohol, polyvinyl acetate, using a highly polar surface treatment agent such as epoxy silane Surface-treated ones are preferred. When an inorganic composition is used as the curable liquid composition, a composition whose surface treatment has been removed by heat cleaning can be used. By using the surface-treated glass fiber, the compatibility between the curable liquid composition and the glass fiber is enhanced, and the glass fiber can be firmly fixed.

  Examples of the form of each sheet member include a flat member, a member having surface irregularities, and a member having a large number of holes. Specific examples include a film, a mesh member, a woven fabric, a knitted fabric, and a nonwoven fabric. In particular, it is preferable that the first layer in the laminate is a mesh sheet and the third layer is a nonwoven sheet. By configuring the first layer 2 with a mesh sheet, the second layer and the concrete structure or the second layer and the third layer can be firmly fixed. When the third layer 4 is formed of a nonwoven fabric sheet, the third layer 4 easily adheres to irregularities of the concrete structure 1.

The first layer 2 is preferably configured to have a higher tensile strength than the second layer 3 and is preferably configured to have a higher tensile strength than the third layer 4.
Here, the tensile strength of the second layer 3 and the third layer 4 is preferably 5 N / 25 mm or more and 150 N / 25 mm or less, more preferably 10 N / 25 mm or more and 100 N / 25 mm or less. Further, the tensile strength of the third layer 4 may be different from that of the second layer 3. The tensile strength of the first layer 2 is preferably at least 300 N / 25 mm, more preferably at least 400 N / 25 mm. When the tensile strength of the first layer 2 is 300 N / 25 mm or more, the strength of the repair material 5 is improved. As the tensile strength, a breaking strength when a sample cut into a width of 25 mm is subjected to a tensile test by a universal testing machine is adopted.

  By providing the first layer 2 having high tensile strength inside the laminate, the concrete pieces are prevented from falling off from the concrete structure to which the repair material 5 has been attached. In other words, the third layer 4 having the property of being easy to follow enhances the adhesion to the concrete structure 1, and the first layer 2 having a high tensile strength imparts the concrete structure to which the repair material has been affixed to the concrete structure 1. I do. The second layer 3 preferably has a lower tensile strength than the first layer 2. This makes it easier to follow the first layer 2 and enhances the adhesion of the first layer 2 to the concrete structure or the third layer 4. As a result, all layers of the repair sheet can be firmly integrated.

(First layer)
The first layer 2 is preferably formed using long fibers. Specifically, the shape includes a woven fabric (woven fabric), a braided fabric, a mesh sheet, and the material includes polyester, polyolefin, vinylon, aramid, carbon fiber, glass fiber, and the like. Especially, it is preferable to consist of a vinylon mesh sheet, a glass long fiber woven fabric, or a mesh sheet. By using long fibers, particularly glass long fibers, for the first layer 2, insufficient strength of the second layer 3 can be compensated. As the glass long fiber, it is preferable to use glass yarn or roving. The glass yarn is a twisted yarn obtained by twisting glass fibers, and the roving is a bundle of glass fibers. The weaving method of the glass long fiber includes a plain weave, a twill weave, and an entangled weave, but from the viewpoint of high strength, the glass long fiber used for the first layer 2 is preferably a plain weave. In addition, the weaving direction may be a biaxial or orthogonal multiaxial woven fabric.

The thickness of the first layer 2 is preferably from 0.1 mm to 1.5 mm, more preferably from 0.3 mm to 1 mm.
The first layer preferably has a basis weight of 50 g / m ² or more, more preferably 60 g / m ² or more, and still more preferably 75 g / m ² or more.
By setting the basis weight in such a range, the strength of the long glass fiber can be improved, and sufficient strength of the repair material 5 can be secured without causing breakage when the concrete pieces are peeled off.

The first layer is preferably a biaxial woven fabric having an opening of 5 mm or more and 25 mm or less, more preferably a biaxial woven fabric having an opening of 5 mm or more and 25 mm or less and having a basis weight of 50 g / m ² or more. . Further, a multiaxial woven fabric having an opening ratio equivalent to that of the biaxial woven fabric may be used.
By setting the opening to this range, the adhesive strength between the second layer and the concrete structure or between the second layer and the third layer can be improved, and sufficient strength of the repair material 5 can be secured. Further, by setting the number of long glass fibers per unit area of the first layer to an appropriate number, the resistance when the first layer breaks out of the second layer is increased, and the sufficient strength of the repair material 5 is secured. Can be.

(Second layer)
The second layer 3 may be in the form of a film, woven fabric, non-woven fabric or the like, and may be in the form of polyester, polyolefin, vinylon, aramid, carbon fiber, glass fiber, or the like. Especially, it is preferable to be comprised with a polypropylene nonwoven fabric or a glass nonwoven fabric. The glass nonwoven fabric has excellent compatibility with the curable liquid composition, so that the curable liquid composition easily penetrates, and when the curable liquid composition is cured, the repair material is firmly fixed to the concrete structure. Can be. Suitable glass nonwovens include, but are not limited to, chopped strand mats, glass paper, felt, and the like.
When using a polypropylene nonwoven fabric, it is desirable to perform a surface treatment on the fiber surface in order to increase the compatibility with the curable liquid composition.

(Third layer)
The material of the third layer 4 includes polyester, polyolefin, vinylon, aramid, carbon fiber, glass fiber, and the like, and is preferably formed of a polypropylene nonwoven fabric or a glass nonwoven fabric. Since the glass nonwoven fabric has excellent compatibility with the curable liquid composition described later, the curable liquid composition easily penetrates, and the repair material is firmly fixed to the concrete structure when the curable liquid composition is cured. Can be done. Suitable glass nonwovens include, but are not limited to, chopped strand mats, glass paper, felt, and the like.
When using a polypropylene nonwoven fabric, it is desirable to perform a surface treatment on the fiber surface in order to increase the compatibility with the curable liquid composition.

  The thickness of the second layer 3 and the third layer 4 is preferably 0.1 mm or more and 1.5 mm or less, more preferably 0.2 mm or more and 0.8 mm or less. When the thickness of the second layer 3 and the third layer 4 is 0.1 mm or more, the strength of the repair material 5 is secured, and when the thickness is 1.5 mm or less, the repair material 5 can be applied to the concrete structure 1. The ease of adhesion is improved.

The second layer 3 and the third layer 4 preferably have a basis weight of 10 g / m ² or more and 2000 g / m ² or less, more preferably a basis weight of 20 g / m ² or more and 1000 g / m ² or less. It is.

When the thickness of the third layer is T ₃ and the thickness of the second layer is T ₂ , T ₃ / T ₂ is preferably 0.05 or more and 3 or less, more preferably 0.1 or more and 1.5 or less. It is as follows. The laminate having such a thickness relationship can achieve both the strength of the repair material 5 and the adhesion to the concrete surface.

(Lamination integration)
The laminate may be integrated by impregnating the curable liquid composition, or may be integrated in advance. By integrating them, displacement of each sheet at the time of application and impregnation can be prevented.
As an integration method, mechanical fiber entanglement, chemical adhesion, or the like can be used, and examples thereof include curling, needle punching, chemical bonding, thermal bonding, and hydroentangling.

  Although FIG. 1 shows a case where the laminate has a two-layer structure, and FIG. 2 shows a case where the laminate has a three-layer structure, the laminate may have four or more layers. Even in the case of four or more layers, the layer disposed as the outermost layer counted from the side in contact with the concrete structure is preferably a layer having a low tensile strength. With such a laminated structure, both the strength of the repair material 5 and the adhesion to the concrete structure can be achieved. Note that the maximum number of stacked layers is not particularly limited.

(Curable liquid composition)
The curable liquid composition is applied and / or impregnated to the repair material, and is, for example, an organic material such as an epoxy resin, a polyurethane, a polyurea, an unsaturated polyester, or a phenol resin, a cement slurry, a gypsum, or a glass. Any of the above inorganic materials may be used. Among them, those containing sodium silicate, potassium silicate and / or lithium silicate and a curing agent are preferable. The concrete structure 1 and the repair material 5 can be bonded by applying and / or impregnating the curable liquid composition to the laminate and then curing the curable liquid composition. By adhering the repair material 5, the life of the deteriorated portion of the concrete structure can be extended, and the occurrence and progress of cracks in the concrete structure can be stopped to prevent the concrete from falling off.

  Sodium silicate, potassium silicate and / or lithium silicate are contained in the curable liquid composition as a component for fixing the concrete structure 1 and the repair material 5. The curable liquid composition can include any one, both, or all of an aqueous solution of sodium silicate, an aqueous solution of potassium silicate, and an aqueous solution of lithium silicate. When sodium silicate is applied and / or impregnated on the surface of the concrete structure 1, it generates calcium hydroxide and CSH gel in the concrete, densifies the concrete surface, and forms a protective layer. be able to. When lithium silicate is applied and / or impregnated on the surface of the concrete structure 1, it forms a hardly soluble solidified material, densifies the concrete surface, and can form a protective layer. In selecting the material of the aqueous silicate solution, it is preferable to use an aqueous solution of sodium silicate from the viewpoint of cost and availability, but when water resistance of the cured product is required, lithium silicate may be mixed at an arbitrary ratio. preferable. Since the solidified lithium silicate is hardly water-soluble, the surface of the concrete structure can be densified to form a protective layer.

Sodium silicate, potassium silicate and / or lithium silicate may be contained in the form of an aqueous solution, for example, in an amount of 50 to 97 parts by mass, and 50 to 95 parts by mass when the entire curable liquid composition is 100 parts by mass. It is preferable that the content be contained. From another viewpoint, sodium silicate, potassium silicate and / or lithium silicate are contained in such an amount as to contain 10 to 60% by mass of SiO ₂ component in terms of SiO _{2 based on} the total mass of the curable liquid composition. It is preferred that

  The hardening of sodium silicate, potassium silicate and / or lithium silicate involves re-bonding with calcium hydroxide in concrete or evaporating moisture in concrete by natural drying to induce a dehydration reaction to form Si-O bonds. Done by Since the dehydration reaction can be promoted by adjusting the pH and moving it to near neutrality, a pH adjuster can be used as a curing agent. Further, by replacing the alkali metal in sodium silicate, potassium silicate and / or lithium silicate with a metal having a valency of 2 or more with a curing agent, a bond of Si—O—metal—O—Si may be formed to promote curing. It is possible.

Also, the curable liquid composition preferably contains 15 wt% to 50 wt% of the SiO ₂ component in terms of SiO _2, comprise SiO ₂ component below 35% by weight to 20% by weight in terms of SiO ₂ Is more preferred. By including SiO ₂ at such a ratio, the repair material 5 and the concrete structure 1 can be firmly bonded. Here, "containing SiO ₂ component of 20 mass% in terms of SiO _2" means that SiO ₂ equivalent 20g is formed upon curing the curable liquid composition 100 g.

(Curing agent)
The curing agent is a component for accelerating the curing of sodium silicate, potassium silicate and / or lithium silicate. The curing agent preferably contains at least one selected from the group consisting of organic acid esters, dialdehydes, inorganic acid esters, organic acid metal salts, inorganic acid metal salts, metal oxides and metal hydroxides, More preferably, one or more compounds selected from the group consisting of organic acid esters, metal oxides, and metal hydroxides are used. The organic acid ester has an advantage that generation of an acid in an aqueous solution can promote formation of a Si—O bond. One preferred example of the curing agent is one or more selected from the group consisting of carbonates and acetates.

The organic acid ester has an advantage that generation of an acid in an aqueous solution can promote formation of a Si—O bond. Examples of the organic acid ester include a carbonate ester and an acetate ester, and among them, triacetin is preferable.
Examples of the dialdehyde include malondialdehyde and the like.
Examples of the inorganic acid esters include esters such as nitric acid, hydrochloric acid, sulfuric acid, and phosphoric acid, such as trimethyl phosphate.
Examples of the organic acid metal salts include alkali metals such as formic acid, acetic acid, malonic acid and carbonic acid, and alkaline earth metal salts such as sodium hydrogen carbonate.
Examples of the inorganic acid metal salt include an alkali metal such as nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid, and an alkaline earth metal salt such as magnesium sulfate.

  The metal oxide and the metal hydroxide form a Si—O—metal—O—Si bond by dissolving the metal ions, and can cure the silicate aqueous solution. A preferred example of the curing agent includes at least one selected from the group consisting of magnesium hydroxide, magnesium carbonate, calcium carbonate, calcium hydroxide, and aluminum silicate.

  When magnesium hydroxide, magnesium carbonate, calcium hydroxide, calcium carbonate, aluminum silicate, or the like is used as a curing agent, the viewpoint of preventing sedimentation of the curing agent in the curable liquid composition and the fact that glass fibers are easily impregnated. From the viewpoint, the particle diameter is preferably 0.5 to 20 μm. In addition, magnesium carbonate is usually sold as basic magnesium carbonate which is a mixture with magnesium hydroxide.

  The amount of the curing agent is preferably 5 to 100 parts by mass with respect to 100 parts by mass of an aqueous solution of 40% by mass of sodium silicate, potassium silicate, lithium silicate or a mixture thereof. By setting it in this range, the curing agent can accelerate the curing of sodium silicate, potassium silicate and / or lithium silicate, and when a liquid organic substance is used as the curing agent, it is not taken into Si—O bonds. Sufficient curing can be achieved without excessively increasing the curing agent component. When a powdered inorganic material is used as the curing agent, the laminate can be sufficiently impregnated with the curable liquid composition without excessively increasing the viscosity of the curable liquid composition.

(Other components)
The curable liquid composition may contain, in addition to the above components, additives known in the art. For example, fillers, dispersants, curing time regulators, pigments, antioxidants and the like can be mentioned. These are not particularly limited, and known ones can be used. The filler may be any of those generally used as a filler. For example, carbon, cellulose, mineral substance fine powder, synthesized inorganic crystal powder and the like can be mentioned.

<How to repair concrete structures>
The method for repairing a concrete structure according to the present invention uses a curable liquid composition and a laminate in which at least two layers of sheet members are laminated, and the curable liquid composition is applied to the laminate. The method includes a coating and impregnating step of coating and / or impregnating, a sticking step of sticking the laminate to a target concrete structure 1, and a curing step of curing the laminate impregnated with the curable liquid composition. . According to such a repairing method, it is not necessary to repeat painting and drying as in the related art, so that workability is excellent. In addition, any of the coating impregnation step and the sticking step may be performed first.

(Application impregnation process)
The coating and impregnating step is performed by coating and impregnating the laminate with the curable liquid composition. This coating and impregnation method is not particularly limited as long as the curable liquid composition is applied and impregnated on the laminate. The timing of applying and impregnating is not particularly limited, that is, the curable liquid composition may be impregnated after forming the laminate, or the laminate may be formed after impregnating the curable liquid composition. Alternatively, the curable liquid composition may be impregnated while forming the laminate. Further, the curable liquid composition may be impregnated before and after the laminate is attached to the target concrete structure.

Examples of the method of impregnating the curable liquid composition include (1) a hand lay-up method in which coating and impregnation is performed manually using a roller, (2) a method of applying and impregnating by spraying, and (3) lamination using a mold. After defining the thickness of the body, a method of applying and impregnating the curable liquid composition to the laminate by press-fitting, (4) defining the thickness of the laminate by depressurization, and then injecting the curable liquid composition into the laminate by vacuum injection (5) a method in which the laminate is immersed in the curable liquid composition and the laminate is continuously impregnated with the curable liquid composition, and then the thickness of the laminate is regulated by a roll; (6) A method in which coating and impregnation are continuously performed by roll transfer is exemplified.
In order to improve the workability at the time of impregnation, and to prevent dust from adhering to the impregnated sheet and to prevent the impregnated sheets from adhering to each other, the front and back surfaces of the laminate may be covered with a resin protective film. This protective film is removed when affixing to the concrete structure 1. The repair material 5 can be obtained by impregnating the laminate with the curable liquid composition by any one of the above methods or a combination thereof.

(Paste process)
The repair material 5 or the laminate produced as described above is attached to the concrete structure 1. Removing air bubbles that have entered between the repair material 5 and the surface of the concrete structure 1 is particularly important for enhancing the adhesion between the repair material 5 and the surface of the concrete structure 1. As a method of removing bubbles, a method of expelling bubbles to the outside of the repair material 5 using a roll or a gold spatula is preferable.

(Curing process)
The curing of the curable liquid composition impregnated in the repair material 5 is performed by placing the repair material 5 in close contact with the concrete structure 1. From the viewpoint of securing time for impregnating the surface of the concrete structure 1 with the curable liquid composition, the curing time of the curable liquid composition is preferably 30 minutes or more and 300 minutes or less, more preferably 45 minutes. More than 240 minutes. The curing time can be adjusted by the acid generation rate of the curable liquid composition, the dissolution rate of the metal salt, and the like. When the curing of the curable liquid composition is completed, the repair material 5 is fixed to the concrete structure 1, and the repair of the concrete structure 1 is completed.

  Hereinafter, the repair material and the repair method for the concrete structure of the present application will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Example 1)
A triaxial net made of a woven fabric of vinylon long fiber (weight per unit area: 90 g / m ² , mesh size: 8 mm, thickness: 0.35 mm, tensile strength: 500 N / 25 mm) is made of a glass nonwoven fabric (basis weight 25 g / m ² , thickness 0.2 mm, By laminating on a glass nonwoven fabric (tensile strength 70 N / 25 mm) and a glass nonwoven fabric (basis weight 50 g / m ² , thickness 0.4 mm, tensile strength 140 N / 25 mm), a laminated body in which three-layered sheet members were laminated was produced.
The triaxial net of vinylon long fibers corresponds to the “first layer”, the glass nonwoven fabric having a basis weight of 50 g / m ² corresponds to the “second layer”, and the glass nonwoven fabric having the basis weight of 25 g / m ^{2 corresponds to} the “third layer”. Equivalent to.

  On the other hand, a curable liquid composition is prepared by mixing 300 g of a bisphenol A type epoxy resin (viscosity of 1,200 mPa · s epoxy equivalent: 200 g / eq) and 36 g of tetraethylenepentamine (manufactured by Tokyo Chemical Industry Co., Ltd.). Was prepared.

  The repair material for the concrete structure of Example 1 was produced by impregnating 200 g of the curable liquid composition into the sheet laminate 400 mm × 400 mm produced above.

(Example 2)
By mixing 250 g of ultrafine particle cement (trade name: Ultra Micro Grain, manufactured by Chatani Sangyo Co., Ltd.), 120 g of ion-exchanged water, and 50 g of latex for cement modification (trade name: L-3642E, manufactured by Nippon A & L Co., Ltd.) A curable liquid composition was prepared.

  A repair material for the concrete structure of Example 2 was produced by impregnating 330 g of the curable liquid composition into the 400 mm × 400 mm sheet laminate produced in Example 1.

(Example 3)
JIS K (including SiO ₂ component of 29 mass% in terms of SiO ₂₎ No. 3 sodium silicate aqueous solution as defined in 1408 100 g and 35% aqueous sodium hydroxide solution 100 g, a latex (Nippon A & L Inc., trade name: SR-151 ) Was mixed with 100 g of calcined kaolin (particle size: 1 µm) as aluminum silicate to prepare a curable liquid composition.

  A repair material for the concrete structure of Example 3 was prepared by impregnating 240 g of the curable liquid composition into the 400 mm × 400 mm sheet laminate prepared in Example 1.

(Example 4)
50 g of potassium silicate aqueous solution (trade name, manufactured by Nippon Chemical Industry Co., Ltd., containing 29% by mass of SiO ₂ component in terms of 1K SiO ₂ ), 50 g of 35% aqueous potassium hydroxide solution, latex (trade name, manufactured by Nippon A & L Co., Ltd .: SR -151) 20 g, and 100 g of calcined kaolin (particle diameter 1 μm) as aluminum silicate were mixed to prepare a curable liquid composition.

A repair material for the concrete structure of Example 4 was produced by impregnating the sheet laminate 400 mm × 400 mm produced in Example 1 with 240 g of the curable liquid composition.
(Example 5)
A glass roving biaxial net made of a glass roving woven fabric (having a basis weight of 124 g / m ² , mesh size of 8 mm, thickness of 0.5 mm, tensile strength of 800 N / 25 mm, and plain weaving) is passed through a glass nonwoven fabric (basis weight of 50 g / m ² , thickness). (0.4 mm, tensile strength: 140 N / 25 mm) to produce a glass fiber laminate in which two layers of sheet members were laminated.
The biaxial net of glass roving corresponds to the “first layer”, and the glass nonwoven fabric having a basis weight of 50 g / m ² corresponds to the “second layer”.

And JIS 3 No. sodium silicate aqueous solution as defined in K 1408 (including SiO ₂ component of 29 mass% in terms of SiO ₂₎ 300 g, triacetin (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 15 g, calcium carbonate (manufactured by Wako Pure Chemical) 45 g and Was mixed to prepare a curable liquid composition.

  The repair material for the concrete structure of Example 5 was produced by impregnating the glass fiber laminate 400 mm × 400 mm produced above with 280 g of the curable liquid composition.

(Example 6)
A glass fiber sheet laminate in which a glass nonwoven fabric (basis weight 25 g / m ² , thickness 0.2 mm, tensile strength 70 N / 25 mm) is further added to the concrete structure side in Example 5, and three layers of sheet members are laminated. The body was made. The added glass nonwoven fabric corresponds to the “third layer”.

(Example 7)
To Example 6, the aqueous sodium silicate solution of 300 g, and No. 3 sodium silicate aqueous solution of 270 g (including the SiO ₂ component of 29 mass% in terms of SiO _2), 21% by weight of lithium silicate solution (SiO ₂ Conversion 30g including the SiO ₂ component, was replaced by a mixture of an including) the Li ₂ O component of 3.0% by weight Li ₂ O terms prepared repair material of the concrete structure in the same manner as in example 6 did.

(Example 8)
A repair material for a concrete structure was prepared in the same manner as in Example 6, except that 30 g of basic magnesium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) having an average particle diameter of 11 μm was used as the curing agent. .

(Example 9)
By individually preparing the curable liquid composition prepared in Example 4 and the sheet laminate 400 mm × 400 mm prepared in Example 1, a repair material for the concrete structure of Example 9 was prepared.

(Comparative Example 1)
A repair material for a concrete structure was prepared in the same manner as in Example 6, except that the second layer was removed.

(Comparative Example 2)
A repair material for a concrete structure was prepared in the same manner as in Example 6, except that the second layer was removed.

<Performance evaluation>
The adhesion of the repair material of the concrete structure of each example to the concrete was evaluated by NEXCO test method 734 "Punching test method for fiber sheet bonding work for prevention of tunnel peeling". Specifically, after applying the repair material prepared in each of the examples to a test body and curing it at a temperature of 23 ° C. and a relative humidity of 50 ° C. for 14 days, a punching test was performed on the repair material stuck to the test body. , The maximum load at a displacement of 10 mm to 50 mm was measured. Table 1 shows the results. The value of "maximum load" in Table 1 is an average value measured three times.
In Example 9, an evaluation sample was prepared by placing a sheet laminate on a test body and applying and impregnating 240 g of the curable liquid composition with a sponge roller.

  From the results shown in Table 1, it became clear that all of Examples 1 to 9 significantly exceeded 0.5 kN required as a repair material for concrete. In each example, the working time from the preparation of the repair material to the performance evaluation was only about 30 minutes for the preparation and the attachment of the repair material. For this reason, in each example, the working time was remarkably shortened as compared with a repairing method which requires time for application and drying of a primer and an overcoat, such as a conventional repairing method.

The reason why the maximum load was lower than 0.5 kN in Comparative Example 1 is considered that all layers of the repair sheet were not integrated.
The reason why the maximum load was lower than 0.5 kN in Comparative Example 2 is considered that the strength of the first layer was insufficient.

  From the results of the preparation of the repair material of each example and the results of the punching test evaluation, it is clear that the concrete repair material of the present invention has excellent adhesion to concrete, and the working time for concrete repair is significantly reduced. And the effect of the present invention was shown.

  According to the repair material of the present invention, the life of a concrete structure can be extended.

DESCRIPTION OF SYMBOLS 1 Concrete structure 2 First layer 3 Second layer 4 Third layer 5 Repair material

Claims (11)

A repair material used for repairing existing concrete structures,
A curable liquid composition;
A laminate in which at least three layers of sheet-like members are laminated,
When the sheet-like member in the laminate is a third layer, a first layer, and a second layer from the concrete structure side, the first layer is a mesh sheet having a higher tensile strength than the second layer. And is configured to have a higher tensile strength than the third layer,
A repair material for a concrete structure in which the third layer is formed of a nonwoven fabric.   The repair material for a concrete structure according to claim 1, wherein the curable liquid composition includes sodium silicate, potassium silicate, and / or lithium silicate and a curing agent.   The repair material for a concrete structure according to claim 1, wherein the second layer and the third layer are formed of a nonwoven fabric. A repair material used for repairing existing concrete structures,
A curable liquid composition;
And a laminate in which at least two layers of sheet-like members are laminated,
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh-like sheet having a higher tensile strength than the second layer. Yes,
The first layer is a repair material for a concrete structure composed of a long fiber fabric. The nonwoven or woven fabric of the long fibers, the repair material of the concrete structure according to claim 1 or 4 which is woven glass nonwoven or glass fiber containing ZrO ₂ of from 5 to 25 wt%. 6. The biaxial woven fabric having a basis weight of 50 g / m ² or more and an opening of 5 to 25 mm or a multiaxial woven fabric having an opening ratio equivalent to that of the biaxial woven fabric. The repair material for a concrete structure according to any one of the above. A repair material used for repairing existing concrete structures,
A curable liquid composition comprising sodium silicate, potassium silicate and / or lithium silicate and a curing agent;
And a laminate in which at least two layers of sheet-like members are laminated,
When the sheet-shaped member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh sheet having a higher tensile strength than the second layer,
Repair of concrete structures containing at least one selected from the group consisting of organic acid esters, dialdehydes, inorganic acid esters, organic acid metal salts, inorganic acid metal salts, metal oxides, and metal hydroxides. material. The curing agent contains magnesium hydroxide or magnesium carbonate,
The repair material for a concrete structure according to claim 7, wherein the particle diameters of the magnesium hydroxide and the magnesium carbonate are 0.5 to 20 µm.   The concrete according to claim 7 or 8, wherein the curing agent is contained in an amount of 5 to 100 parts by mass with respect to 100 parts by mass of an aqueous solution of 40% by mass of sodium silicate, potassium silicate, lithium silicate or a mixture thereof. Repair material for structures. A repair method for repairing an existing concrete structure using the repair material for a concrete structure according to any one of claims 1 to 9, comprising a curable liquid composition and a laminate in which at least two layers of sheet members are laminated. hand,
An application impregnation step of applying and impregnating the laminate with the curable liquid composition,
An attaching step of attaching the laminate impregnated with the curable liquid composition to a target concrete structure,
A curing step of curing the laminate impregnated with the curable liquid composition,
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh-like sheet having a higher tensile strength than the second layer. A method for repairing a concrete structure, characterized in that: A repair method for repairing an existing concrete structure using the repair material for a concrete structure according to any one of claims 1 to 9, comprising a curable liquid composition and a laminate in which at least two layers of sheet members are laminated. hand,
An attaching step of attaching the laminate to a target concrete structure,
An application impregnation step of applying and impregnating the curable liquid composition to the laminate attached to a concrete structure,
A curing step of curing the laminate impregnated with the curable liquid composition,
When the sheet-like member in the laminate is a first layer and a second layer from the concrete structure side, the first layer is configured by a mesh-like sheet having a higher tensile strength than the second layer. A method for repairing a concrete structure, characterized in that: