JP2017186825A - Repair material of concrete structure and repair method of concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repair material of a concrete structure capable of improving reinforcement strength by securing adhesive strength.SOLUTION: The present invention is a repair material used for repairing an existing concrete structure, and is the repair material of the concrete structure composed of a base material of laminating a sheet-like member of at least two layers and a hardening resin composition impregnated into the base material, in which in the sheet-like member in the base material, when set as a first layer and a second layer from the concrete structure side, the first layer is a sheet-like member of combining a multifilament in a multiple spindle mesh shape, and the second layer is a liquid-permeable sheet-like member of 2.0 N or more in tear strength, and viscosity at 25°C of the hardening resin composition is 400-3000 mPa.s.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a material for repairing a concrete structure and a method for repairing a concrete structure.

  Since concrete structures have the advantages of high strength, excellent workability, and low cost, many concrete structures have been made mainly in Japan during the high growth period. Although concrete structures are excellent in durability, neutralization is caused by long-term use of carbon dioxide in the atmosphere along with moisture, and chloride ions contained in sea breeze and antifreeze spray penetrate. It may corrode and expand, and cracks may occur. A piece of concrete may peel off due to such cracks as a starting point or due to freezing of moisture soaked into the concrete.

  As an attempt to prevent such peeling of concrete, Patent Documents 1 and 2 and the like propose using a laminate base material for preventing peeling that combines a mesh sheet and a nonwoven fabric. Such a layered substrate for preventing peeling is usually impregnated with a curable resin composition such as an adhesive or a binder and adhered to concrete as a repair material.

JP 2012-26238 A JP2013-0119146A Japanese Patent No. 4262461

However, if the viscosity of the curable resin composition such as an adhesive or a binder is too high, it takes time to impregnate the base material, and if the viscosity is too low, a peeling prevention repair material is applied to a vertical surface. There was a problem that dripping of the cured composition occurred.
Furthermore, as in Patent Document 2, when an inorganic cured product having low tear strength is used as the nonwoven fabric, sufficient reinforcing strength cannot be obtained as a repair base material.
In addition, when the mesh sheet is in direct contact with the concrete surface, a sufficient curing composition such as an adhesive or a binder is not supplied to the back side of the mesh, and there is a problem that the adhesive strength is not sufficiently developed.

  The present invention has been made in view of the above problems, and has an object to provide a repair material for a concrete structure and a repair method for the concrete structure that can secure adhesive strength and improve reinforcement strength. To do.

The present application includes the following inventions.
(1) A repair material used for repairing an existing concrete structure, comprising a base material on which at least two layers of sheet-like members are laminated, and a curable resin composition impregnated in the base material, When the sheet-like member in the base material is a first layer and a second layer from the concrete structure side, the first layer is a sheet-like member in which multifilaments are combined in a multiaxial mesh shape, and the second layer The layer is a sheet-like member having a tear strength of 2.0 N or more and a liquid permeability, and the viscosity of the curable resin composition at 25 ° C. is 400 to 3000 mPa · s. .
(2) The curable resin composition comprises a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture thereof and a pozzolanic active substance having an electric conductivity difference of 0.4 mS / cm or more. Repair material for the above concrete structures.
(3) The repair material of the said concrete structure whose numerical value n represented by the following numerical formula of the aqueous solution of the said sodium silicate, potassium silicate, lithium silicate, or these mixtures is 0.5-1.1.
n = S / M
(S: number of moles of silicon contained in aqueous solution, M: number of moles of alkali metal contained in aqueous solution)
(4) The ratio of sodium, potassium, lithium or a mixture thereof derived from the silicate compound contained in the cured product obtained from the curable resin composition is M ₂ O (M Is a repair material for a concrete structure as described above which is 5 to 30% by weight in terms of sodium, potassium and lithium.
(5) The pozzolanic active substance is a compound containing aluminum, and the ratio of the aluminum contained in the cured product obtained from the curable resin composition is converted to Al ₂ O ₃ with respect to the dry solid content of the cured product. The repair material for a concrete structure according to the above, which is 20 to 40% by weight.
(6) The repair material for a concrete structure as described above, wherein the pozzolanic active substance is metakaolin.
(7) The polymer emulsion containing acrylic rubber, styrene butadiene rubber or a mixture thereof is 3 to 10% by weight as the solid content of the polymer based on the dry solid content of the cured product, based on the dried cured product of the curable resin composition. The material for repairing a concrete structure as described above, which is blended.
(8) The repair material for a concrete structure according to the above, wherein a numerical value X represented by the following mathematical formula of the first layer is 2.0 or more.
X = A × B
(A: Tensile strength in one direction kN / 50 mm, B: Number of axes)
(9) The repair material for a concrete structure according to the above, wherein the first layer is a sheet-like member in which multifilaments having a tensile strength of 150 N or more are combined in a multiaxial mesh shape with an interval of 5 to 25 mm.
(10) The repair material for a concrete structure according to the above, comprising a sheet-like member having a porosity of 90% or more and a liquid permeability as the third layer between the first layer and the concrete structure.
(11) A repair method for repairing an existing concrete structure using the repair material for a concrete structure according to any one of the above, wherein the curable resin composition is impregnated in a repair base material. A method for repairing a concrete structure, comprising a pasting step for pasting, and a curing step for curing the repair base material impregnated with the curable resin composition.

As the base material for repairing a concrete structure of the present invention, an inorganic curable resin composition can be used, and the adhesive strength is ensured without minimizing or impairing the deterioration of the inherent fire resistance of the concrete structure. Thus, the reinforcing strength can be improved.
Moreover, in the repair method of the concrete structure of this invention, a concrete structure can be repaired simply and reliably using the base material for repair mentioned above.

It is typical sectional drawing which shows an example of the repair form of the concrete structure using the repair material (double layer structure) of the concrete structure of this invention. It is typical sectional drawing which shows an example of the repair form of the concrete structure using the repair material (three-layer structure) of the concrete structure of this invention.

<Repair material>
The repair material in the present application is used for repairing an existing concrete structure, and includes a curable resin composition and a repair base material impregnated with the curable resin composition. The curable resin composition and the repair base material may exist separately, but at the time of repair, the repair base material is impregnated with the repair base material as described later.
As shown in FIGS. 1 and 2, the repair material 5 is applied to and impregnated with the curable resin composition in the repair material on the surface of the concrete structure 1, for example, by being attached to the concrete structure 1. Repairs the concrete structure 1 by hardening or bonding with the concrete structure.

<Repair base material>
The repair base material is configured by laminating at least two sheet-like members. For example, as shown in FIG. 1, the repair base material is used such that the first layer 2 and the second layer 3 are laminated in this order from the concrete structure side. Moreover, as shown in FIG. 2, you may have the structure by which the 3rd layer 4, the 1st layer 2, and the 2nd layer 3 were laminated | stacked in this order from the concrete structure side.
In particular, the repair base material is preferably a sheet-like member in which the first layer is a combination of multifilaments in a multiaxial mesh shape.
Furthermore, the second layer is preferably a sheet-like member having a tear strength of 2.0 N or more and a 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 constructed using long fibers, and preferably has a tensile strength of 150 N or more. The value X represented by the formula (1) of the sheet-like member obtained by combining multifilaments in a multiaxial mesh shape is preferably 2.0 or more, and is 2.5 or more, 2.8 or more, or 3.0 or more. More preferably.
X = A × B (1)
Here, A represents the tensile strength kN / 50 mm in one direction of the sheet-like member, and B represents the number of axes of the sheet-like member. A can take an arbitrary value by changing the number of multifilaments per 50 mm. Examples of B include those having a range of 2 to 4. Among these, A is preferably 150 kN or more, and B is preferably 2 to 3.
By this structure, the 1st layer 2 can satisfy | fill the function as a strength layer which receives the concrete piece which falls from a concrete structure.

  Examples of the material of the first layer 2 include polyester, polyolefin, vinylon, aramid, carbon fiber, and glass fiber. Especially, it is preferable to consist of a vinylon mesh sheet or a glass mesh sheet. It is preferable to use glass yarn or roving as the long glass fiber. The glass yarn is obtained by twisting glass fibers to form a twisted yarn, and the roving is obtained by focusing glass fibers. Examples of the method of weaving the multiaxial mesh include plain weave, twill weave, entangled weave, and braided fabric. Further, the direction of weaving of the multiaxial mesh may be a biaxial orthogonal or more multiaxial woven fabric.

The thickness of the first layer 2 is preferably 0.1 mm or more and 1.5 mm or less, 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 within this range, the tensile strength can be improved and sufficient proof stress of the repair material 5 can be ensured without causing breakage when the concrete piece is peeled off.

The first layer is preferably a biaxial woven fabric having an opening of 5 mm or more and 25 mm or less, and more preferably a biaxial woven fabric having an opening of 5 mm or more and 25 mm or less and a basis weight of 50 g / mm ² or more. Further, it may be a multiaxial woven fabric having an opening ratio equivalent to that of the 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 interval of 5 to 25 mm.
By setting the mesh opening in this range, the adhesive strength 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 ensured. In addition, by setting the number of long fibers per unit area of the first layer to an appropriate number, it is possible to increase the resistance when the first layer breaks through the second layer, and to secure 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-like member is preferably 2.0 N or more. By setting the tear strength to 2.0 N or more, the second layer 3 can satisfy the function as a reinforcing layer that increases the resistance when the first layer breaks through the second layer.

Examples of the shape of the second layer 3 include woven fabric and nonwoven fabric. Examples of the material include polyester, polyolefin, vinylon, aramid, carbon fiber, and glass fiber. Especially, it is preferable that it is comprised with a polypropylene nonwoven fabric or a glass nonwoven fabric, and it is especially more preferable that it is a long fiber nonwoven fabric. The glass nonwoven fabric is excellent in compatibility with the curable resin composition, so that the curable resin composition easily penetrates, and when the curable resin composition is cured, the repair material is firmly fixed to the concrete structure. Can do. Suitable glass nonwoven fabrics include chopped strand mats, glass paper, felts and the like.
When a polypropylene nonwoven fabric is used, it is desirable to perform a surface treatment on the fiber surface in order to enhance compatibility with the curable resin composition.

The thickness of the second layer 3 is preferably from 0.1 mm to 1.0 mm, more preferably from 0.15 mm to 0.5 mm.
By setting the thickness in such a range, the base layer of the curable resin composition is impregnated while satisfying the function as a reinforcing layer for increasing the resistance when the first layer breaks out of the second layer. This is economically advantageous.

(Third layer)
The third layer 4 is preferably a liquid-permeable sheet-like member having a porosity of 90% or more. Thereby, since the impregnation property of curable resin composition can be ensured, the function as an adhesive layer which improves the adhesive strength of the repair material 5 and a concrete structure can be satisfy | filled.
A nonwoven fabric is mentioned as a shape of the 3rd layer 4. FIG. Examples of the material include polyester, polyolefin, vinylon, aramid, carbon fiber, glass fiber, and the like, and it is preferably made of a polypropylene nonwoven fabric or a glass nonwoven fabric. The glass nonwoven fabric is excellent in compatibility with the curable resin composition, so that the curable resin composition easily penetrates, and when the curable resin composition is cured, the repair material is firmly fixed to the concrete structure. Can do. Suitable glass nonwoven fabrics include chopped strand mats, glass paper, felts and the like.
When using a polypropylene nonwoven fabric, it is preferable to perform a surface treatment on the fiber surface in order to enhance compatibility with the curable resin composition.

  The thickness of 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 third layer 4 is 0.1 mm or more, the adhesive strength between the repair material 5 and the concrete structure is ensured, and when it is 1.5 mm or less, the base material is impregnated with the curable resin composition. The amount can be reduced, which is economically advantageous.

(Stacked integration)
The repair base material constituted by laminating at least two layers of sheet-like members may be integrated by impregnating the curable resin composition, but is preferably integrated in advance. By integrating, it is possible to prevent displacement of each sheet member during coating impregnation.
The integration method can utilize mechanical fiber entanglement, chemical bonding, etc., and examples thereof include crimping, needle punching, chemical bonding, thermal bonding, hydroentangling, and the like.

  Although FIG. 1 shows a case where the repair base material has a two-layer structure and FIG. 2 shows a case where the repair base material has a three-layer structure, the repair base material may have four or more layers. Even in the case of four or more layers, it is preferable that the second layer 3 is arranged in a layer outside the first layer 2 from the side in contact with the concrete structure. With such a laminated structure, both the strength of the repair material 5 and the adhesion to the concrete structure can be achieved. The maximum number of stacked layers is not particularly limited.

(Curable resin composition)
The curable resin composition is applied and / or impregnated on a repair base material. The concrete structure 1 and the repair material 5 can be bonded by applying and / or impregnating the curable resin composition to the laminate and then curing the curable resin composition. For example, the curable resin composition may be liquid. By adhering the repair material 5, it is possible to prevent the concrete pieces from peeling off from the deteriorated portion of the concrete structure.

The curable resin composition may be any of organic materials such as epoxy resin, polyurethane, polyurea, unsaturated polyester, and phenol resin, and inorganic materials such as cement slurry, gypsum, and glass. Among these, the use of an inorganic material is preferable from the viewpoint of ensuring without impairing the fire resistance of the concrete structure.
As the inorganic curable resin composition, a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture thereof and a pozzolanic active substance (hereinafter sometimes referred to as “geopolymer”) is particularly preferable. . In geopolymers, the difference in specific gravity between the liquid component composed of an aqueous silicate solution and the solid component composed of a pozzolanic active material is small compared to the specific gravity difference between water and cement contained in the cement slurry, so the components in the curable resin composition are separated. Can be suppressed.

In addition, sodium silicate and potassium silicate can generate calcium hydroxide and C—S—H gel in concrete when applied to and / or impregnated on the surface of the concrete structure 1. 5 and the concrete structure 1 can be further strengthened in adhesive strength.
Such a curable resin composition preferably has a viscosity at 25 ° C. of 400 to 3000 mPa · s. By setting it as such a viscosity, the impregnation property to the base material for repair can be ensured. Moreover, dripping of the curable resin composition at the time of sticking to a concrete structure can be prevented.

  In particular, when a geopolymer is used, the pozzolanic active substance preferably has an electrical conductivity difference of 0.4 mS / cm or more, 0.5 mS / cm or more, 0.6 mS / cm or more, or 0.7 mS / cm or more. Some are more preferable, and 0.8 mS / cm or more, 1.0 mS / cm or more, and 1.2 mS / cm or more are more preferable. By setting it as such an electrical conductivity difference, the reactivity with silicate aqueous solution can fully be ensured, and the adhesive strength of the repair material 5 and the concrete structure 1 can be raised. The electrical conductivity difference here is an index related to the reactivity of the pozzolanic active substance induced by the alkaline substance, and the electric conductivity before and after the pozzolanic active substance is charged in the saturated calcium hydroxide aqueous solution obtained by the evaluation method described later Means the difference.

Here, the pozzolanic active substance is a substance that hardens by reacting with water and calcium oxide, calcium hydroxide, aluminum hydroxide or the like, for example, silica dust, diatomaceous earth, talc, aerosil, white carbon, kaolin, metakaolin. , Activated clay, and acid clay. Of these, metakaolin is preferred. The pozzolanic active substance usually has a silica component content of 40% by weight or more when the silica component in the pozzolanic active substance is converted to SiO ₂ or the alumina component content when the alumina component is converted to Al ₂ O ₃ What is 30 weight% or more is preferable.
The pozzolanic active substance is usually in the form of a lump or powder, but the pozzolanic active substance may be used in the form of a lump or powder. Moreover, in order to activate, you may use what changed the state using methods, such as a spraying process, a grinding | pulverization classification, and the effect | action of mechanical energy.

As a thermal spraying method, a thermal spraying technique applied to a ceramic coating is applied. Examples of the thermal spraying technique include a plasma spraying method, a high energy gas spraying method, and an arc spraying method. 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 for pulverization and classification. Examples of the pulverization include a method using a jet mill, a roll mill, a ball mill and the like. In addition, classification includes a method using a sieve, specific gravity, wind force, wet sedimentation and the like. These means can be arbitrarily used together.
Examples of the method for applying mechanical energy include a method using a ball medium mill, a medium stirring mill, a roller mill, and the like. The mechanical energy to be applied is preferably 0.5 kwh / kg to 30 kwh / kg in order to minimize the load while being appropriately activated.

The curable resin composition, for example, sodium, potassium, lithium or a mixture thereof derived from the silicate aqueous solution in the geopolymer has a total content of the dry solid content of the cured product obtained from the curable resin composition. , M ₂ O (M is sodium, potassium and lithium), preferably 5 to 30% by weight, more preferably 10 to 30% by weight. The content of aluminum derived from the pozzolanic active substance is preferably 20 to 40% by weight, preferably 25 to 35% by weight, converted to Al ₂ O ₃ with respect to the dry solid content of the cured product. It is more preferable.

  Further, the curable resin composition preferably has a numerical value n represented by the following formula of an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture thereof of 0.4 to 1.1, 0.5 to What is 1.1 is more preferable, and what is 0.5 to 1.0 is more preferable.

(Other ingredients)
The curable resin composition may contain an additive known in the art in addition to the above components. For example, fillers, modifiers, dispersants, curing time adjusting agents, 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. Examples thereof include carbon, cellulose, fine mineral powder, and synthesized inorganic crystal powder. Examples of the modifier include various metal salts capable of reacting with an aqueous silicate solution, such as light-burned magnesium oxide and zinc white. Examples of the polymer emulsion include acrylic rubber, styrene butadiene rubber, or a mixture thereof. These additives can be used in any content as long as the intended action of the curable resin composition is not impaired. In particular, the polymer emulsion is preferably blended so that the solid content weight of the polymer is 3 to 10% by weight with respect to the total weight of the dry solid content of the curable resin composition. Thereby, the fluidity | liquidity of curable resin composition can be improved, the adhesive strength of hardened | cured material can be improved, and the drying shrinkage of hardened | cured material can be suppressed.

  The amount of impregnation of the curable resin composition into the laminate is not particularly limited, and the curable resin composition is uniformly held throughout the laminate, and the entire laminate is solidified by the curing of the curable resin composition. It is preferable to adjust so that it can be integrated. For example, the mass ratio of the laminate: curable resin composition is preferably about 1: 4 to 1:12, more preferably 1: 4 to 1:10.

<Repair method for concrete structures>
The method for repairing a concrete structure of the present invention can be performed using the above-described repair material for a concrete structure. Application and / or impregnation step of applying and / or impregnating the above-described curable resin composition to the repair base material including the laminate, and a concrete structure targeted for the repair base material coated and impregnated with the curable resin composition And a curing step of curing the repair base material coated and impregnated with the curable resin composition. According to such a repair method, since it is not necessary to repeat coating and drying as in the prior art, the work can be performed easily and efficiently, and the workability is excellent.

(Coating impregnation process)
The coating impregnation step is performed by coating and impregnating the repair base material with the curable resin composition. The laminate may be impregnated with the curable resin composition, the laminate may be impregnated with the curable resin composition, or the curable resin composition may be formed while forming the laminate. An object may be impregnated. Further, the curable resin composition may be impregnated before or after the laminate is attached to the target concrete structure.

Examples of the method of impregnating the curable resin composition include (1) a hand lay-up method in which application impregnation is performed manually using a roller, (2) a method of application impregnation by spraying, and (3) lamination by a mold. A method of applying and impregnating a laminate with a curable resin composition by press-fitting after defining the thickness of the body, (4) After defining the thickness of the laminate by reducing pressure, the curable resin composition is applied to the laminate by injecting under reduced pressure (5) A method of impregnating the laminate with a roll after the laminate is immersed in the curable resin composition and the laminate is continuously impregnated with the curable resin composition, (6) Examples thereof include a method in which coating and impregnation are continuously performed by roll transfer. These may be used in combination.
In order to improve workability at the time of impregnation, and to prevent dust from adhering to the impregnated sheets and from adhering to each other, the laminate may be covered with a protective film made of a resin. This protective film is removed when it is applied to a concrete structure.

(Attaching process)
The obtained repair material is stuck on a concrete structure. At this time, removing air bubbles that have entered between the repair material and the surface of the concrete structure is particularly important in order to improve the adhesion between the repair material and the surface of the concrete structure. As a method for removing bubbles, a method of expelling bubbles to the outside of the repair material using a roll or a gold spatula is suitable.

(Curing process)
Curing of the curable resin composition impregnated in the repair material is performed by placing the repair material in close contact with the concrete structure. From the viewpoint of ensuring the time for impregnating the curable resin composition on the surface of the concrete structure, the curing time of the curable resin composition is preferably 30 to 300 minutes, more preferably 45 to 240 minutes. is there. Curing time depends on the amount and type of curing catalyst in the case of organic materials, depending on the amount of water contained in the case of inorganic materials, particularly sodium, potassium, lithium or these derived from silicate aqueous solutions in the case of geopolymers. Content ratio of mixture, ratio of SiO ₂ and M ₂ O (M is sodium, potassium and lithium) derived from aqueous silicate solution (SiO ₂ / M ₂ O), electric conductivity difference of pozzolanic active substance and aluminum content It can be adjusted according to the rate. When the curing of the curable resin composition is completed, the repair material is fixed to the concrete structure, and the repair of the concrete structure can be completed.

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

Example 1
A triaxial mesh sheet made of vinylon multifilament (weight per unit area 90 g / m ² , mesh opening 8 mm, thickness 0.35 mm, X = 3.0) is made into a hydrophilic polypropylene spunbonded nonwoven fabric (unit weight 30 g / m ² , thickness 0). A laminate was prepared by laminating to 2 mm, tear strength 16 N).
A triaxial mesh sheet corresponds to the “first layer”, and a spunbonded nonwoven fabric having a basis weight of 30 g / m ² corresponds to the “second layer”.
As the curable resin composition, a low-viscosity two-component epoxy resin (E206S viscosity 600 mPa · s manufactured by Konishi Co., Ltd.) was used.
The repair material for the concrete structure of Example 1 was produced by impregnating and curing 70 g of the curable resin composition on the sheet laminate 400 mm × 400 mm produced above.
All of these operations were performed in an environment of 23 ° C.

(Example 2)
A laminated body was produced by laminating a glass nonwoven fabric (a basis weight of 25 g / m ² , a thickness of 0.2 mm, a porosity of 95%) as a third layer on the sheet produced in Example 1.
By mixing 250 g of ultrafine 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 resin composition was prepared. The viscosity of the adjusted curable resin composition was 250 Pa · s.
The repair material for the concrete structure of Example 2 was produced by impregnating and curing 140 g of the curable resin composition on the sheet laminate 400 mm × 400 mm produced above.
All of these operations were performed in an environment of 23 ° C.

(Example 3)
3g sodium silicate aqueous solution 100g prescribed in JIS K 1408, 35% sodium hydroxide aqueous solution 100g (n = 0.4), latex (Nippon A & L Co., Ltd. product name: SR-151) 20g is stirred for 24 hours and silicic acid An aqueous salt solution was obtained. A curable resin composition was prepared by mixing with 100 g of calcined kaolin (trade name: SP-33, conductivity difference 0.8 mS / cm, manufactured by BASF). The viscosity of the obtained curable resin composition was 800 Pa · s. The content of Na ₂ O (converted value) in the cured product is 12.8% by weight and the content of Al ₂ O ₃ (converted value) is 31.0% by weight with respect to the total weight of the cured product. there were.
The repair material for the concrete structure of Example 3 was produced by impregnating and curing 90 g of the curable resin composition on the sheet laminate 400 mm × 400 mm produced in Example 1.
All of these operations were performed in an environment of 23 ° C.

Example 4
The repair material for the concrete structure of Example 4 was produced by impregnating and curing 110 g of the curable resin composition produced in Example 3 on the sheet laminate 400 mm × 400 mm produced in Example 2.
All of these operations were performed in an environment of 23 ° C.

(Example 5)
3g sodium silicate aqueous solution 100g prescribed in JIS K 1408, 30% sodium hydroxide aqueous solution 50g (n = 0.7), latex (Nippon A & L Co., Ltd., trade name: SR-151) 15g is stirred for 24 hours and silicic acid An aqueous salt solution was obtained. 2. Using an ultra fine mill manufactured by Mitsubishi Heavy Industries, Ltd. (using zirconia balls with a diameter of 10 mm, a ball filling rate of 85%, a mixed solution of triethanolamine 25% and ethanol 75% as a grinding aid is added with 0.6% of metakaolin). The curable resin composition was mixed with 130 g of calcined kaolin (trade name: SP-33, conductivity difference 1.1 mS / cm, manufactured by BASF) treated at 3 KW / kg for 3 hours under an environmental condition of 10 ° C. A product was prepared. The viscosity of the obtained curable resin composition was 1000 Pa · s.
The content of Na ₂ O (converted value) in the cured product is 11.3 wt% and the content of Al ₂ O ₃ (converted value) is 30.9 wt% with respect to the total weight of the cured product. there were.
The sheet laminate 400 mm × 400 mm produced in Example 2 was impregnated with 110 g of the curable resin composition in an environment of 10 ° C. and cured in an environment of 23 ° C., whereby the concrete structure of Example 5 was obtained. Repair material was prepared.

(Example 6)
A biaxial mesh sheet of glass roving made of glass roving woven fabric (basis weight 125 g / m ² , mesh opening 8 mm, thickness 0.5 mm, X = 3.2, plain weave) A laminate was prepared by laminating m ² , thickness 0.2 mm, tear strength 16 N), and glass nonwoven fabric (weight per unit area 25 g / m ² , thickness 0.2 mm, porosity 95%).
The biaxial mesh sheet of glass roving corresponds to the “first layer”, the spunbond nonwoven fabric corresponds to the “second layer”, and the glass nonwoven fabric corresponds to the “third layer”.
A repair material for the concrete structure of Example 5 was prepared by impregnating 110 g of the curable resin composition prepared in Example 2 into the sheet laminate 400 mm × 400 mm prepared above.
All of these operations were performed in an environment of 23 ° C.

(Comparative Example 1)
A repair material for a concrete structure was prepared in the same manner as in Example 1 except that the second layer was a glass nonwoven fabric (weight per unit area 25 g / m ² , thickness 0.2 mm, tear strength 0.4 N). did.

(Comparative Example 2)
In contrast to Example 6, the first layer was the same as Example 5 except that a glass roving woven fabric (weight per unit area 60 g / m ² , mesh opening 9 mm, thickness 0.5 mm, X = 1.6, plain weave) was used. A repair material for concrete structures was prepared.

(Comparative Example 3)
The concrete layer was repaired in the same manner as in Example 1 except that the third layer was a hydrophilized polypropylene spunbonded nonwoven fabric (weight per unit area 30 g / m ² , thickness 0.2 mm, porosity 85%). The material was made.

(Comparative Example 4)
A repair material for a concrete structure was produced in the same manner as in Example 1 except that the second layer was removed from Example 1. In the repair material, dripping of the curable resin composition occurs, and the appearance of the repair surface is impaired. Therefore, the peeling prevention performance and the adhesion force are not measured.

(Comparative Example 5)
A concrete structure repair material was prepared in the same manner as in Example 3, except that the mixing impregnation operation was performed in Example 10 in an environment of 10 ° C and cured in an environment of 23 ° C.

(viscosity)
The viscosity of the curable resin composition was measured in accordance with JIS K 7117, using a Viscostar Plus R type manufactured by Fungi Lab Co., Ltd., and the viscosity started to stabilize at 23 ° C. for the first time using a R4 rotor at a rotation speed of 50 min ⁻¹ . Measurements were taken at the timing.
(Electric conductivity difference)
Regarding pozzolanic active substances, “Cement Concrete Research, Vol. 19, pp. 63-68, 1989 ”, the electrical conductivity of 200 ml of a saturated aqueous solution of Ca (OH) ₂ is measured under the condition of 40 ± 1 ° C. Subsequently, 5 g of metakaolin was added, stirred, and the electric conductivity after 2 minutes was measured. The difference from the electric conductivity before the addition was defined as the electric conductivity difference.
(Evaluation of anti-peeling performance)
The anti-peeling performance of the concrete structure repair materials of each Example and Comparative Example was evaluated by a punching test described in “Bridge Structure Design Guideline Concrete Fragment Prevention Section” of the Metropolitan Expressway Co., Ltd. Specifically, the repair material produced in each example was attached to a test body, cured at a temperature of 23 ° C. and a relative humidity of 50% for 3 days, and then subjected to a push-out test on the repair material attached to the test body. As a result, the maximum load at a displacement of 10 mm to 50 mm was measured. The results are shown in Table 1. In Table 1, the value of “punch resistance” is an average value measured three times.
(Adhesive strength)
The adhesion strength of the concrete structure repair materials of each Example and Comparative Example to the concrete was evaluated by a Kenken-type simple tensile tester (Techno Tester R-10000ND). Specifically, after applying the repair material prepared in each example to a flat plate (nominal 300) defined in JIS A 5371 and curing at a temperature of 23 ° C. and a relative humidity of 50 ° C. for 3 days, the simple tensile test is performed. The adhesive strength was measured based on the standard usage of the machine. The results are shown in Table 1.

  From the results of the punching test of the repair material of each example and the evaluation of the adhesive strength, it is confirmed that the concrete repair material of the present invention has excellent adhesion to concrete and can be greatly improved in anti-peeling performance. It was done.

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

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

Claims (11)

A repair material used to repair existing concrete structures,
It consists of a base material on which at least two layers of sheet-like members are laminated, and a curable resin composition impregnated in the base material, and the sheet-like member in the base material is composed of a first layer and a concrete structure side. In the case of the second layer, the first layer is a sheet-like member in which multifilaments are combined in a multiaxial mesh shape, and the second layer is a tear-permeable 2.0N or more liquid-permeable sheet-like member, A repair material for a concrete structure, wherein the curable resin composition has a viscosity at 25 ° C. of 400 to 3000 mPa · s.   The curable resin composition comprises a composition containing an aqueous solution of sodium silicate, potassium silicate, lithium silicate or a mixture thereof and a pozzolanic active substance having an electric conductivity difference of 0.4 mS / cm or more. Repair material for concrete structures described in 1. The repair material for a concrete structure according to claim 2, wherein a numerical value n represented by the following formula of the aqueous solution of the sodium silicate, potassium silicate, lithium silicate, or a mixture thereof is 0.5 to 1.1.
n = S / M
(S: number of moles of silicon contained in aqueous solution, M: number of moles of alkali metal contained in aqueous solution) The ratio of sodium, potassium, lithium or a mixture thereof derived from the silicate compound contained in the cured product obtained from the curable resin composition is M ₂ O (M is sodium, The repair material for concrete structures according to claim 2 or 3, which is 5 to 30% by weight in terms of potassium and lithium. The pozzolanic active substance is a compound containing aluminum, and the ratio of the aluminum contained in the cured product obtained from the curable resin composition is 20 to 40 in terms of Al ₂ O ₃ with respect to the dry solid content of the cured product. The material for repairing a concrete structure according to any one of claims 2 to 4, wherein the repair material is weight%.   The repair material for a concrete structure according to any one of claims 2 to 5, wherein the pozzolanic active substance is metakaolin.   A polymer emulsion containing acrylic rubber, styrene butadiene rubber or a mixture thereof is blended in a dry solid of the curable resin composition in an amount of 3 to 10% by weight as a solid content of the polymer based on the dry solid content of the cured product. The repair material for a concrete structure according to any one of claims 1 to 6. The repair material for a concrete structure according to any one of claims 1 to 7, wherein a numerical value X represented by the following mathematical formula of the first layer is 2.0 or more.
X = A × B
(A: Tensile strength in one direction kN / 50 mm, B: Number of axes)   The material for repairing a concrete structure according to any one of claims 1 to 8, wherein the first layer is a sheet-like member in which multifilaments having a tensile strength of 150 N or more are combined in a multiaxial mesh shape with an interval of 5 to 25 mm. .   The repair material for a concrete structure according to any one of claims 1 to 9, further comprising a liquid-permeable sheet-like member having a porosity of 90% or more as a third layer between the first layer and the concrete structure. .   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 10, wherein the repair base material is impregnated in a repair base material and the concrete structure is repaired. A method for repairing a concrete structure, comprising: an attaching step for attaching to an object; and a curing step for curing the repair base material impregnated with the curable resin composition.