JP2019124053A - Repair method for concrete structure - Google Patents

Abstract

To provide a repair method for concrete structures that has higher strength and can be repaired simply and easily for repair materials used for repairing concrete structures.SOLUTION: A repair method for concrete structure used for repairing an existing concrete structure 1 comprises a preparing process for preparing curable liquid composition comprising a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture thereof and a curing agent, and a repair base material 5 in which at least two layers of sheet-like members are laminated, an impregnating step for impregnating the repair base material 5 with the curable liquid composition and sticking it to the concrete structure 1, and an applying step for applying an aqueous solution containing a divalent or higher cation to the repair base material 5 impregnated with the curable liquid composition and attached to the concrete structure 1.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a method of repairing a concrete structure.

Because concrete structures have the advantage of high strength, excellent workability, and low cost, many concrete structures have been created in Japan, mainly in the high growth period. Concrete structures are excellent in durability, but carbonation in the atmosphere with moisture will cause carbonation, and chloride ions contained in the sea breeze and antifreeze agent penetrate when used for many years. It may be corroded and expanded, which may cause cracking.
As an attempt to prevent such peeling of concrete, Patent Documents 1 and 2 and the like propose using various peel-preventing laminated base materials combining a mesh sheet and a non-woven fabric.

JP, 2012-26238, A Unexamined-Japanese-Patent No. 2013-019146

With regard to a repair material used for repairing a concrete structure, a material having higher strength is required in order to reliably prevent the concrete from falling off. At the same time, there is a strong demand for a method of repairing a concrete structure that can be easily and easily repaired, and can fully exhibit the performance of the original repair material.
The present disclosure has been made in view of the above problems, and a repair material used for repairing a concrete structure is higher in strength, and the repair of a concrete structure can be easily and easily performed. Intended to provide a method.

The present application includes the following inventions.
(1) A repair method using a repair material used to repair an existing concrete structure,
A curable liquid composition comprising a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture of these and a curing agent, and a repair substrate on which at least two sheet members are laminated are prepared. Process,
Impregnating the curable liquid composition into the repair substrate and attaching it to a concrete structure;
And a step of applying an aqueous solution containing divalent or higher cations to the repair substrate impregnated with the curable liquid composition and attached to the concrete structure. Method.
(2) A composition containing as a main component at least one selected from the group consisting of dialdehydes, inorganic acid esters, organic acid metal salts, inorganic acid metal salts, metal oxides and metal hydroxides. The repair method of the concrete structure mentioned above which consists of.
(3) The repair method of the concrete structure mentioned above whose said metal oxide is metakaolin.
(4) The method for repairing a concrete structure as described above, wherein the metal oxide is a pozzolanic active material having a difference in electric conductivity of 0.4 mS / cm or more.
(5) The repair method of the concrete structure mentioned above whose said curable liquid composition shows a viscosity of 400-3000 mPa * s at 25 degreeC.
(6) The method for repairing a concrete structure as described above, wherein the aqueous solution containing divalent or higher valent cations is an aqueous solution of magnesium sulfate or aluminum sulfate.
(7) The aqueous solution containing the divalent or higher cation contains 40 or more of sodium silicate, potassium silicate, lithium silicate or a mixture thereof contained in the curable liquid composition in which the coating amount is impregnated into the repair substrate. The repair method of the concrete structure mentioned above which is 0.5-4 weight part as solid content with respect to 100 weight part of aqueous solution of weight% conversion.
(8) The method for repairing a concrete structure as described above, wherein the aqueous solution containing divalent or higher valent cation has a concentration of 5 to 30% by weight.
(9) When the sheet-like member is a first layer and a second layer from the side of the concrete structure, the first layer makes a multifilament having a tensile strength of 150 N or more in a multiaxial mesh shape with an opening of 5 to 25 mm. The method for repairing a concrete structure as described above, which is a combined sheet-like member, and the second layer is a sheet-like member having a tear strength of 2.0 N or more and liquid permeability.

The base material for repairing a concrete structure of the present invention can use an inorganic curable liquid composition, and secures the adhesive strength by minimizing or not deteriorating the inherent fire resistance of the concrete structure. The reinforcement strength can be improved.
Moreover, in the repair method of the concrete structure of this invention, a concrete structure can be easily and reliably repaired using the base material for a repair mentioned above.

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

The method for repairing a concrete structure according to the present invention is a method for repairing using a repair material used for repairing an existing concrete structure, which mainly comprises:
A curable liquid composition comprising a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture of these, and a curing agent, a repair substrate in which at least two sheet-like members are laminated, and Preparing an aqueous solution containing the cation of
Impregnating the curable liquid composition into the repair substrate and attaching it to a concrete structure;
Applying the aqueous solution containing the divalent or higher cation to the repair base material impregnated with the curable liquid composition and attached to a concrete structure.
According to such a repair method, it is not necessary to repeat painting and drying as in the prior art, and the operation can be performed simply and efficiently, and the workability is also excellent.

[Curable liquid composition, base material for repair, preparation of aqueous solution containing divalent or higher cation]
The repair material in the present application is used to repair an existing concrete structure, and comprises a repair base on which at least two layers of sheet-like members are laminated, and a curable liquid composition impregnated into the repair base. And an aqueous solution containing divalent or higher cations applied to a repair substrate impregnated with the curable liquid composition. The curable liquid composition and the repair substrate may be present separately, but at the time of repair, the curable liquid composition is impregnated into the repair substrate as described later.
As shown in FIGS. 1 and 2, the repair materials 5 and 15 are applied to, for example, the concrete structure 1 so that the curable liquid composition in the repair material is coated and impregnated on the surface of the concrete structure 1, The concrete structure 1 is repaired by the composition curing or bonding with the concrete structure.

(Base material for repair)
The repair substrate is configured by laminating at least two sheet-like members. For example, as shown in FIG. 1, the repair material 5 is used such that the first layer 2 and the second layer 3 are laminated in this order from the concrete structure 1 side. Further, as shown in FIG. 2, the repair material 15 may have a configuration in which the third layer 4, the first layer 2 and the second layer 3 are laminated in this order from the concrete structure 1 side.
In particular, the first layer is preferably a sheet-like member in which multifilaments are combined in a multiaxial mesh shape.
Further, the second layer is preferably a sheet-like member having a tear strength of 2.0 N or more and liquid permeability.

(First layer)
The first layer 2 is preferably a sheet-like member in which multifilaments are combined in a multiaxial mesh shape. The multifilament is preferably formed using long fibers, and preferably has a tensile strength of 150 N or more. It is preferable that the value X represented by Formula (1) of the sheet-like member which combined multifilaments in multiaxial mesh shape is 2.0 or more, and 2.5 or more, 2.8 or more, or 3.0 or more It is more preferable that
X = A × B (1)
Here, A represents the tensile strength kN / 50 mm of the sheet-like member in one direction, and B represents the number of axes of the sheet-like member. A can take an arbitrary value by changing the number per 50 mm of multifilaments. As B, one having a range of 2 to 4 can be mentioned. Among them, A is preferably 0.75 kN or more, and B is preferably 2 to 3.
According to this configuration, the first layer 2 can fulfill the function as a load bearing layer for receiving concrete pieces falling from the concrete structure.

  Examples of the material of the first layer 2 include polyester, polyolefin, vinylon, aramid, carbon fiber, glass fiber and the like. Especially, it is preferable to consist of a vinylon mesh sheet or a glass mesh sheet. Glass fiber is preferably glass yarn or roving. Glass yarn is obtained by twisting glass fibers to form a twisted yarn, and roving is obtained by collecting glass fibers. The weave method of the multiaxial mesh includes plain weave, twill weave, entangled weave, knitted fabric and the like. Further, the direction of weave of the multiaxial mesh may be a biaxial or more multiaxial woven fabric orthogonal to each other.

The thickness of the first layer 2 is preferably 0.1 mm or more and 1.5 mm or less, and more preferably 0.3 mm or more and 1 mm or less.
The first layer preferably has a basis weight of 50 g / mm ² or more, more preferably 60 g / mm ² or more, and still more preferably 75 g / mm ² or more.
By setting the weight per unit area in such a range, the tensile strength can be improved, and a sufficient proof strength of the repair material 5 can be secured without causing breakage at the time of peeling of concrete pieces.

The first layer is preferably a biaxial woven fabric with an opening of 5 mm or more and 25 mm or less, and more preferably a biaxial woven fabric with a coating weight of 50 g / mm ² or more at an opening of 5 mm or more and 25 mm or less. In addition, it may be a multiaxial woven fabric having an aperture ratio equivalent to that of a biaxial woven fabric.
In particular, the first layer is more preferably a biaxial or triaxial mesh sheet-like member in which multifilaments having a tensile strength of 150 N or more are combined at an opening of 5 to 25 mm.
By setting the opening within this range, the adhesion between the second layer and the concrete structure or the second layer and the third layer can be improved, and sufficient strength of the repair material 5 can be secured. In addition, with the number of long fibers per unit area of the first layer being an appropriate number, it is possible to increase the resistance when the first layer breaks out the second layer, and to ensure sufficient strength of the repair material 5 it can.

(Second layer)
The second layer 3 is preferably a liquid-permeable sheet-like member. The tear strength of the liquid-permeable sheet member is preferably 2.0 N or more. By setting the tear strength to 2.0 N or more, the second layer 3 can fulfill the function as a reinforcing layer that enhances the resistance when the first layer tears out the second layer.

Examples of the shape of the second layer 3 include woven fabric and non-woven fabric. Examples of the material include polyester, polyolefin, vinylon, aramid, carbon fiber, glass fiber and the like. Among them, a polypropylene non-woven fabric or a glass non-woven fabric is preferable, and in particular, a long-fiber non-woven fabric is more preferable. Since the glass nonwoven fabric is excellent in compatibility with the curable liquid composition, 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. Suitable glass nonwovens include chopped strand mats, glass paper, felts, and the like.
In the case of using a polypropylene non-woven fabric, in order to enhance the compatibility with the curable liquid composition, the fiber can also be subjected to a hydrophilization treatment.

The thickness of the second layer 3 is preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.15 mm or more and 0.5 mm or less.
While satisfying the function as a reinforcing layer that enhances the resistance when the first layer breaks out the second layer by setting it in such a thickness range, the amount of the curable liquid composition impregnated onto the substrate It can be economically advantageous.

(Laminated integration)
The repair substrate configured by laminating at least two sheet-like members may be integrated by impregnating the curable liquid composition, but it is preferable to integrate in advance. By unifying them, it is possible to prevent the displacement of each sheet member at the time of coating and impregnation.
As a method of integration, mechanical fiber entanglement, chemical adhesion and the like can be used, and examples thereof include crimp, needle punch, chemical bond, thermal bond, water flow entanglement and the like.

  Although FIG. 1 shows the case where the repair substrate has a two-layer structure, and FIG. 2 shows the case where the repair substrate has a three-layer structure, the repair substrate may have four or more layers. Also in the case of four or more layers, it is preferable that the second layer 3 is disposed in a layer outside the first layer 2, counting from the side in contact with the concrete structure. Such a laminated structure can achieve both the strength of the repair materials 5 and 15 and the adhesion to the concrete structure 1. The maximum number of laminated layers of the repair base material is not particularly limited.

(Curable liquid composition)
The curable liquid composition is to be applied and / or impregnated to a repair substrate. The concrete structure and the repair material can be adhered by applying and / or impregnating the curable liquid composition to a repair substrate and then curing the curable liquid composition. For example, the curable liquid composition includes one that is liquid. By bonding the repair material, it is possible to prevent exfoliation of concrete pieces from the deteriorated portion of the concrete structure.

  As the curable liquid composition, a composition comprising an aqueous solution (sodium silicate aqueous solution) of sodium silicate, potassium silicate, lithium silicate or a mixture thereof and a curing agent is preferable. The aqueous solution of silicate can be used by adjusting the pH with an aqueous solution of an alkali metal hydroxide such as sodium hydroxide and potassium hydroxide. An aqueous solution of an alkali metal hydroxide aqueous solution adjusted in pH is also an aqueous solution of silicate.

In addition, since sodium silicate and potassium silicate can form calcium hydroxide and C—S—H gel in concrete when applied and / or impregnated on the surface of concrete structure 1, repair materials and The adhesive strength of the concrete structure can be further strengthened.
As for such a curable liquid composition, that whose viscosity in 25 degreeC is 400-3000 mPa * s is preferable. By setting it as such a viscosity, the impregnatability to the base material for repair can be ensured. Moreover, the dripping of the hardenable liquid composition at the time of sticking to a concrete structure can be prevented.

  The curing agent is a component for accelerating the curing of sodium silicate, potassium silicate, lithium silicate or a mixture thereof. As the curing agent, one that is adjusted to around pH neutral to accelerate the dehydration condensation reaction can be mentioned. In addition, in order to form a bond of Si-O-metal-O-Si and accelerate the curing, an alkali metal in sodium silicate, potassium silicate, lithium silicate or a mixture thereof is replaced with a divalent or higher metal. What can be done. The curing agent preferably contains one or more selected from the group consisting of organic acid ester, dialdehyde, inorganic acid ester, organic acid metal salt, inorganic acid metal salt, metal oxide and metal hydroxide, It is more preferable to use one or more compounds selected from the group consisting of organic acid esters, metal oxides and metal hydroxides.

Organic acid esters have the advantage that they can promote the formation of Si-O bonds by generating an acid in aqueous solution. As an organic acid ester, carbonate ester, an acetic acid ester etc. are mentioned, for example. Among these, triacetin is preferred.
Examples of dialdehydes include malondialdehyde and the like.
Examples of the inorganic acid ester include esters of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid and the like, for example, trimethyl phosphate and the like.
Examples of the organic acid metal salt include alkali metal such as formic acid, acetic acid, malonic acid and carbonic acid, and alkaline earth metal salts such as sodium hydrogen carbonate.
Examples of inorganic acid metal salts include alkali metals such as nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid, and alkaline earth metal salts, such as magnesium sulfate, magnesium carbonate and calcium carbonate.

The metal oxide and the metal hydroxide form a Si-O-metal-O-Si bond by the dissolution of metal ions, and can cure sodium silicate, potassium silicate, lithium silicate or a mixture of these. . Examples of metal oxides and metal hydroxides include magnesium oxide, calcium oxide, zinc oxide, magnesium hydroxide, calcium hydroxide and pozzolanic active substances.
The metal oxide is preferably a pozzolanic active substance (hereinafter, the curable liquid composition in which the curing agent is a pozzolanic active substance may be referred to as "geopolymer"). A pozzolanic active substance is a substance that does not react with water itself but hardens by reacting with a mixture of water and calcium oxide or calcium hydroxide, and examples thereof include silica dust, diatomaceous earth, talc, aerosil, White carbon, kaolin, metakaolin, activated white earth, acid white earth etc. are mentioned, Among them, metakaolin is preferable.
The pozzolanic active substance preferably has an electric conductivity difference of 0.4 mS / cm or more, more preferably 0.5 mS / cm or more, 0.6 mS / cm or more, or 0.7 mS / cm or more, 0. More preferably, it is 8 mS / cm or more, 1.0 mS / cm or more, 1.2 mS / cm or more. By setting such a difference in electric conductivity, the reactivity with the aqueous solution of silicate can be sufficiently secured, and the adhesive strength between the repair material 5 and the concrete structure 1 can be enhanced. The electrical conductivity difference here is an index related to the reactivity of the pozzolanic active substance induced by the alkaline substance, and the electrical conductivity before and after the pozzolanic active substance injection of the saturated calcium hydroxide aqueous solution obtained by the evaluation method described later Means the difference between
The pozzolanic active material has a silica component content of 40% by weight or more when the silica component in the pozzolanic active material is converted to SiO ₂ or an alumina component content of 30 weight when the alumina component is converted to Al ₂ O ₃ % Or more is preferable.
The pozzolanic active substance is usually in the form of mass or powder, but mass or powder may be used as it is. Moreover, in order to make it active, you may use that from which the state was changed using methods, such as a thermal-spray process, pulverization classification, and the effect | action of mechanical energy.

As a method of thermal spray treatment, a thermal spray technique applied to a ceramic coating is applied. The thermal spraying technique includes, for example, plasma thermal spraying, high energy gas thermal spraying, and arc thermal spraying. Preferably, the material powder is melted at a temperature of 2000 to 16000 ° C. and sprayed at a speed of 30 to 800 m / sec to obtain a powder having a specific surface area of 0.1 to 100 m ² / g.
Any known method can be adopted as a method of pulverizing and classifying. The pulverization may be carried out using a jet mill, a roll mill, a ball mill or the like. Further, classification may be carried out using a sieve, specific gravity, wind force, wet sedimentation, or the like. These means can be optionally used in combination.
As a method of applying mechanical energy, a method using a ball medium mill, a medium agitation type mill, a roller mill or the like can be mentioned. The mechanical energy to be applied is preferably 0.5 to 30 kwh / kg in order to minimize the load while appropriately activating.

The compounding amount of the curing agent varies depending on the dissolution rate to sodium silicate, potassium silicate, lithium silicate or a mixture thereof, and is 0.2 to 150 parts by weight based on 100 parts by weight of the whole composition. Is preferred. By setting it in this range, it is possible to sufficiently contribute to the acceleration of curing of sodium silicate, potassium silicate, lithium silicate or a mixture thereof. Moreover, also when using a liquid organic substance as a hardening | curing agent, the hardening | curing agent component taken in in a Si-O bond can be maintained and sufficient hardening can be led. Furthermore, even when using a powder inorganic substance as the curing agent, the composition can be sufficiently impregnated into the repair substrate without excessively increasing the viscosity of the composition. From another point of view, the curing agent is contained in an amount equivalent to 0.1 to 100 parts by weight with respect to 100 parts by weight of an aqueous solution in terms of 40% by weight of sodium silicate, potassium silicate, lithium silicate or a mixture thereof Although it is preferable, it is preferable to contain by 1 to 80 weight part equivalent, and it is more preferable to contain by 1 to 60 weight part equivalent.
In particular, in the case where the curing agent here contains a strong acid salt containing a divalent or higher valent cation as an inorganic acid metal salt, they take into account the viscosity (that is, the workability) at the time of application within the range described above. It is preferable to select an amount that can secure a pot life, that is, a smaller amount (amount near the lower limit).

The total content of sodium, potassium, lithium or a mixture thereof derived from an aqueous solution of silicate in the geopolymer is M ₂ O (where M is sodium) relative to the dry solid content of the cured product obtained from the curable liquid composition In terms of potassium and lithium) is preferably 5 to 30% by weight, and more preferably 10 to 30% by weight. In addition, the content of aluminum derived from the pozzolanic active substance is preferably 20 to 40% by weight and 25 to 35% by weight in terms of Al ₂ O ₃ with respect to the dry solid content of the cured product. Is more preferred.

Furthermore, the curable liquid composition is preferably one having a numerical value n of 0.4 to 1.1, which is represented by the following formula of an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture thereof, and more preferably 0.5 to 0.5 More preferably, the compound is 1.1, more preferably 0.5 to 1.0.
n = S / M
(S: the number of moles of silicon contained in the aqueous solution, M: the number of moles of alkali metal contained in the aqueous solution).

(Other ingredients)
The curable liquid composition may contain, in addition to the above components, additives known in the art. For example, fillers, dispersants, curing time adjusters, pigments, antioxidants, polymer emulsions 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 fine powder, synthesized inorganic crystal powder and the like can be mentioned. Examples of the polymer emulsion include acrylic rubber, styrene butadiene rubber, and mixtures thereof. These additives can be used in any content as long as the intended effect of the curable liquid composition is not impaired. In particular, the polymer emulsion is preferably blended such that the solid content weight of the polymer is 3 to 10% by weight based on the total weight of the dry solid content of the curable liquid composition. Thereby, the fluidity of the curable liquid composition can be improved, the adhesive strength of the cured product can be improved, and the drying shrinkage of the cured product can be suppressed.

  The amount of impregnation of the curable liquid composition onto the repair substrate is not particularly limited, and the curable liquid composition is uniformly retained over the entire repair substrate, and the curing of the curable liquid composition is performed for repair. It is preferable to adjust so that the whole base material can be integrated firmly. For example, the weight ratio of the repair substrate to the curable liquid composition is preferably about 1: 4 to 1:12, and more preferably 1: 4 to 1:10.

(An aqueous solution containing a divalent or higher cation)
The aqueous solution containing a divalent or higher cation may have any pH as long as it contains a divalent or higher cation. Among them, those which are strong acid salts are preferable. Magnesium, aluminum, etc. are mentioned as a cation more than bivalence here. Examples of strong acid salts include salts of hydrochloric acid, sulfuric acid, nitric acid and the like. Among these, magnesium sulfate or aluminum sulfate is preferable.
The concentration of the aqueous solution containing divalent or higher cations is preferably 2 to 50% by weight, and more preferably 5 to 30% by weight. If the concentration is too low, the coating amount increases and the workability deteriorates, and if the concentration is too high, uniform coating becomes difficult and the workability deteriorates. Among them, an aqueous solution containing divalent or higher valent cations preferably has a concentration of 5 to 30% by weight.

Impregnation and sticking of a curable liquid composition
(Coating and impregnating process)
The curable liquid composition is applied and / or impregnated into the repair substrate. The substrate for repair may be formed and then impregnated with the curable liquid composition, or the curable liquid composition may be impregnated before forming the substrate for repair, or the substrate for repair is formed. While curing, the curable liquid composition may be impregnated. In addition, the curable liquid composition may be impregnated either before or after the repair base material is attached to the target concrete structure.

As a method of impregnating the curable liquid composition, for example, (1) hand lay-up method of applying and impregnating manually by using a roller, (2) method of coating and impregnating by spray, (3) repair by a mold A method of applying and impregnating a curable liquid composition to a repair substrate by press-fitting after defining the thickness of the substrate for a substrate, (4) A curable liquid composition by depressurizing injection after defining a thickness of the repair substrate by depressurization A method of impregnating a substrate for repair with a composition, (5) immersing a substrate for repair in a curable liquid composition to continuously impregnate the substrate for repair with the curable liquid composition, and then using a roll. The method of specifying thickness to the base material for repair, (6) The method of performing coating impregnation continuously by roll transfer, etc. are mentioned. These may be used in combination.
The front and back surfaces of the base for repair may be covered with a resin protective film in order to enhance the workability at the time of impregnation, and to prevent the adhesion of dust to the impregnated sheet and the adhesion between the impregnated sheets. This protective film is removed when it is attached to a concrete structure.

(Pasting process)
The repair substrate impregnated with the curable liquid composition is attached to a concrete structure. At this time, it is important to remove the air bubbles intruding between the surface of the concrete structure and the repair base material impregnated with the curable liquid composition in order to improve the adhesion to the surface of the concrete structure. As a method of removing air bubbles, a method using a roll or a gold spatula to expel air bubbles to the outside is preferable.
The coating and impregnating step and the sticking step may be performed independently or simultaneously.

(Curing process)
The hardening of the curable liquid composition impregnated in the repair substrate is carried out by placing it in close contact with the concrete structure. The curing time of the curable liquid composition is preferably 15 to 300 minutes, more preferably 30 to 240 minutes, from the viewpoint of securing the time for impregnating the surface of the concrete structure with the curable liquid composition. is there. The curing time is the content of sodium, potassium, lithium or a mixture thereof derived from an aqueous solution of silicate, or the ratio of SiO ₂ to M ₂ O (M is sodium, potassium and lithium) derived from an aqueous solution of silicate (SiO ₂ / It can be adjusted by M ₂ O), by the amount of water contained and the amount of the curing agent, and by the electric conductivity difference of the pozzolanic active substance, the content of aluminum and the like.
When curing of the curable liquid composition is completed, a repair substrate in which the curable liquid composition is impregnated into the concrete structure can be fixed.

[Coating of aqueous solution]
The aqueous solution containing divalent or higher cations is placed in a state in which the repair base material in which the curable liquid composition is impregnated is brought into close contact with the concrete structure. From the viewpoint of assisting curing of the curable liquid composition, it is preferable that the time to start coating of the aqueous solution containing divalent or higher cations be performed within 7 days immediately after the application of the curable liquid composition. More preferably, after 30 minutes to 24 hours. By carrying out in this range, the transpiration of the water | moisture content contained in a curable liquid composition can fully advance, and the aqueous solution containing the cation more than bivalence can fully permeate.
The coating method can use a general method, and a brush, a roller, a spray gun, etc. are mentioned.
When the application of the aqueous solution containing divalent or higher cations is completed, the hardening state of the curable liquid composition can be further strengthened, and the repair of the concrete structure can be completed.

Coating of an aqueous solution containing divalent or higher cations onto a repair substrate impregnated with a curable liquid composition is carried out for the purpose of assisting the curing of the curable liquid composition, and a curable liquid It is preferable to carry out uniformly over the entire repair substrate impregnated with the composition.
The aqueous solution containing a divalent or higher cation has a solid content relative to 100 parts by weight of an aqueous solution in terms of 40% by weight of sodium silicate, potassium silicate, lithium silicate or a mixture thereof contained in the impregnated curable liquid composition. It is preferable to apply so as to be 0.5 to 10 parts by weight, and more preferably 0.5 to 4 parts by weight. By setting it in this range, it is possible to obtain an effect of assisting sufficient curing, and it is possible to prevent the deposition of the coating component on the surface and to improve the appearance.
Hereinafter, the method for repairing a concrete structure of the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Example A-1
In a silicate aqueous solution (SiO ₂ = 16.3%, Na ₂ O = 10.5%) prepared by adding 62 g of a 27 wt% sodium hydroxide aqueous solution to 46 g of a No. 3 sodium silicate aqueous solution specified by JIS K 1408 As a polymer emulsion of components, 11 g of styrene butadiene rubber emulsion (trade name: LX407 F43, manufactured by Nippon Zeon Co., Ltd.) was added and stirred for 24 hours to obtain an aqueous solution of silicate containing other components.
A curable liquid composition was prepared by mixing 59 g of metakaolin as a curing agent (trade name: SP-33 electric conductivity difference 0.8 mS / cm) as a curing agent in the above aqueous solution.
In addition, a biaxial mesh sheet (a basis weight of 90 g / m ² , an opening of 7 mm, a thickness of 0.35 mm, X = 2.5) made of vinylon multifilament having a tensile strength of 250 N was made of glass nonwoven fabric (a basis weight of 25 g / m ²⁾ Two sheets of thickness 0.2 mm, tensile strength 45 N / 25 mm) were piled up, and 1 sheet was piled under, and the base material for repair which laminated the sheet-like member of four layers was produced.
By impregnating 170 g of the curable liquid composition into the prepared repair substrate 400 mm × 400 mm, a repair substrate impregnated with the curable liquid composition was prepared.
13. Affixing the repair base material impregnated with the curable liquid composition to a test body of a concrete structure, and after 3 hours, a 10 wt% aqueous solution of magnesium sulfate as an aqueous solution containing divalent or higher cations. Apply 4 g (1.9 parts by weight as solid content to 100 parts by weight of a 40% by mass equivalent silicate aqueous solution) and allow to stand for 3 days under standard conditions (temperature 23 ° C., relative humidity 50%), An evaluation sample was obtained.

Example A-2
As an aqueous solution containing divalent or higher cations, 10.05 g of a 20% by weight aqueous solution of aluminum sulfate (2.9 parts by weight as solid content with respect to 100 parts by weight of a 40% equivalent aqueous solution of silicate) is used Evaluation samples were obtained as in Example A-1.

Example A-3
As an aqueous solution containing divalent or higher cations, 44.7 g of a 3% by weight aqueous solution of magnesium sulfate (1.9 parts by weight as solid content with respect to 100 parts by weight of a 40% equivalent aqueous solution of silicate) was used Evaluation samples were obtained as in Example A-1.

Comparative Example A-1
An evaluation sample was obtained in the same manner as Example A-1 except that the aqueous solution containing divalent or higher cations was not coated.

Comparative Example A-2
Except using 13.4 g of a 10% by weight sodium sulfate aqueous solution (1.9 parts by weight as solid content with respect to 100 parts by weight of a 40% equivalent silicate aqueous solution) as an aqueous solution containing divalent or higher valent cations Evaluation samples were obtained as in Example A-1.

(Electrical conductivity difference)
For the pozzolanic active substance, the conductivity of 200 ml of a Ca (OH) ₂ saturated aqueous solution is measured under the conditions of 40 ± 1 ° C. according to “Cement Concrete Research, Vol. 19, pp. 63-68, 1989”. Subsequently, 5 g of metakaolin was added, stirred, and the electric conductivity after 2 minutes was measured, and the difference from the electric conductivity before the introduction was regarded as the difference in electric conductivity.

(Push-out strength)
The anti-slip-proof performance of the repair material of the concrete structure of each example and comparative example was evaluated by the push-out test described in "bridge structure design procedure concrete piece peel-off prevention knitting" of Metropolitan Expressway Stock Company. Specifically, the repair material prepared in each example and comparative example was attached to a test body, and was aged for 3 days at a temperature of 23 ° C. and a relative humidity of 50 ° C. Thereafter, the maximum load at a displacement of 10 to 50 mm was measured by performing a push-out test on the repair material stuck to the test body.

Example B-1
As a curable liquid composition, 150 g of No. 3 sodium silicate aqueous solution prescribed by JIS K 1408, 22.5 g of calcium carbonate porous particles as a curing agent (manufactured by Shiroishi Calcium Co., Ltd. trade name: Brilliant-15), 7.5 g of triacetin A curable liquid composition was prepared by mixing 0.4 g of a nonionic surfactant (polyoxyethylene (5) lauryl ether) as a dispersant for other components (manufactured by Tokyo Chemical Industry Co., Ltd.).
An evaluation sample was obtained in the same manner as Example A-1 except that the obtained curable liquid composition was used. That is, in this example, 13.4 g of a 10% by weight aqueous solution of magnesium sulfate (100 parts by weight of an aqueous solution of 40 wt. Parts by weight) was applied and aged for 3 days under standard conditions (temperature 23 ° C., relative humidity 50%) to obtain an evaluation sample.

Example B-2
As an aqueous solution containing divalent or higher cations, 17.9 g of a 20% by weight aqueous solution of aluminum sulfate (2.6 parts by weight as solid content with respect to 100 parts by weight of a 40% equivalent aqueous solution of silicate) is used Evaluation samples were obtained as in Example B-1.

Comparative Example B-1
Evaluation samples were obtained in the same manner as Example B-1 except that the aqueous solution containing divalent or higher cations was not coated.

<Performance evaluation>
The punching strength was measured in the same manner as described above with respect to the repair materials attached to the test bodies of the above-described Examples and Comparative Examples. The results are shown in Table 2.

1 Concrete structure 2 First layer 3 Second layer 4 Third layer 5, 15 Repair material

Claims (9)

A repair method using a repair material used to repair an existing concrete structure,
A curable liquid composition comprising a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture of these, and a curing agent, a repair substrate in which at least two sheet-like members are laminated, and Preparing an aqueous solution containing the cation of
Impregnating the curable liquid composition into the repair substrate and attaching it to a concrete structure;
And a step of applying an aqueous solution containing the divalent or higher cation to the repair base material impregnated with the curable liquid composition and attached to a concrete structure. Repair method.   Composition in which the curing agent contains, as a main component, at least one selected from the group consisting of dialdehydes, organic acid esters, inorganic acid esters, organic acid metal salts, inorganic acid metal salts, metal oxides, and metal hydroxides The method of repairing a concrete structure according to claim 1, wherein the concrete structure comprises an object.   The method according to claim 2, wherein the metal oxide is metakaolin.   The method for repairing a concrete structure according to claim 2 or 3, wherein the metal oxide comprises a pozzolanic active material having an electrical conductivity difference of 0.4 mS / cm or more.   The said curable liquid composition shows a viscosity of 400-3000 mPa * s at 25 degreeC, The repair method of the concrete structure as described in any one of Claims 1-4.   The method for repairing a concrete structure according to any one of claims 1 to 5, wherein the aqueous solution containing divalent or higher valent cation is magnesium sulfate or aluminum sulfate aqueous solution.   The aqueous solution containing the divalent or higher cation contains 40 wt% of sodium silicate, potassium silicate, lithium silicate or a mixture thereof in the curable liquid composition in which the coating amount is impregnated into the repair substrate The method for repairing a concrete structure according to any one of claims 1 to 6, wherein the solid content is 0.5 to 4 parts by weight with respect to 100 parts by weight of the aqueous solution.   The method for repairing a concrete structure according to any one of claims 1 to 7, wherein the aqueous solution containing divalent or higher valent cations has a concentration of 5 to 30% by weight.   When the sheet-like member is a first layer and a second layer from the side of the concrete structure, a sheet in which the first layer combines multifilaments having a tensile strength of 150 N or more in a multiaxial mesh shape with an opening of 5 to 25 mm The method for repairing a concrete structure according to any one of claims 1 to 8, wherein the second layer is a sheet-like member having a tear strength of 2.0 N or more and liquid permeability.