JP2005213842A - Concrete-surface structure and its constructing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface structure for preventing a peeling, in which a concrete-structure surface layer can be constructed even under a moist state and which can be formed without using a fiber sheet by the execution of works in a short time, and a constructing method for the surface structure. <P>SOLUTION: The layer of an epoxy resin primer, to which a silane coupling agent is mixed, is formed to the concrete-structure surface layer. The layer of 0.8 to 4 mm being composed of polyurethane or polyurea having a tensile strength of 7 N/mm<SP>2</SP>or more and a tensile rupture elongation of 50 to 800% is formed on the epoxy resin primer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a surface structure for preventing a concrete piece from peeling off from a concrete structure and a method for constructing the surface structure.

  In a concrete structure, a part of a concrete member may be peeled off as a fragment based on defects during construction, damage due to an earthquake or collision, neutralization, salt damage, chemical degradation such as alkali aggregate reaction, and the like. In order to prevent such concrete pieces from peeling off, conventional fiber sheets such as glass cloth, synthetic resin fiber sheets, carbon fiber sheets, and the like, including methods of covering concrete surfaces with metals such as iron plates, have been made of synthetic resin materials. Alternatively, a method of attaching to a concrete surface using an inorganic material such as cement has been proposed and implemented.

  In such a construction method, it is not possible to obtain a sufficient peeling prevention effect simply by covering the concrete surface layer portion with a high-strength material. For example, when a concrete piece is displaced due to expansion due to corrosion of a reinforcing bar from a crack, which is a model case of deterioration, the peeling prevention layer follows the displacement, withstands considerable stress, and holds the peeling piece. is required. From the standpoint of exhibiting such required performance, peeling prevention systems using fiber sheets have been widely implemented (Non-Patent Document 1).

Published by the Japan Highway Public Corporation “Concrete Fragment Prevention Measures Manual” November 2000

  However, in the construction method using a fiber sheet, a great deal of labor is required for cutting and sticking the sheet, and it is difficult to attach to the uneven surface or to adjust the dimensions to the structure. There was a problem that it would be long, and there was a need to develop a simpler construction method. In the development of such construction methods, concrete structures that require anti-stripping measures are often wet on the surface due to weather conditions and installation environment. It was required to be a thing. Further, in Japan, since the surface temperature of the concrete structure is assumed to fluctuate in the range of about -20 to + 60 ° C, it has been required to have sufficient peeling prevention performance under such a wide temperature condition. In addition, when the place where waterproof coating is required, such as around the edge of a girder of a concrete bridge, is located at the top of the traffic intersection, it is applied with waterproof performance, chloride ion or carbon dioxide gas shielding performance, etc. It was required for the film.

  Accordingly, an object of the present invention is to provide a concrete surface structure that satisfies the above-mentioned required performance without using a fiber sheet and can be constructed by a simple operation, and a construction method thereof.

That is, according to the present invention, the surface layer of the concrete structure has an epoxy resin primer layer with a tensile strength of 1 N / mm ² or more and a thickness with a tensile strength of 7 N / mm ² or more and a tensile elongation at break of 50 to 800%. There is provided a concrete surface structure in which 0.8 to 4 mm polyurethane or polyurea layers are laminated. As the epoxy resin primer, it is preferable to use a silane coupling agent, particularly one containing an epoxy group-containing silane coupling agent. As the polyurethane or polyurea, it is particularly preferable to use those having a brittle temperature of -25 ° C or lower.

According to the present invention, the surface layer of the concrete structure is coated with an epoxy resin primer having a viscosity in the range of 20 to 5000 mPa · s and a tensile strength at curing of 1 N / mm ² or more, and then cured. A polyurethane or polyurea curable composition having a tensile strength of 7 N / mm ² or more and a tensile elongation at break of 50 to 800% is sprayed to form a polyurethane or polyurea layer having a thickness of 0.8 to 4 mm. A featured method of constructing a concrete surface structure is provided. Also in the polyurethane or polyurea, those having a brittle temperature of −25 ° C. or less are particularly preferable.

  Moreover, in the said construction method of a concrete surface structure, it is preferable to use the solvent-free epoxy resin primer which contains 0.1-5 weight part of silane coupling agents per 100 weight part of primer as an epoxy resin primer. In this case, the present invention can also be applied to a concrete surface structure whose surface layer is in a wet state. Furthermore, it is preferable to use a polyurethane or polyurea curable composition having a touch-drying time in the range of 1 to 120 seconds.

  In the present invention, the tensile strength and tensile elongation at break are measured according to JIS K7113 and JIS K6251, the embrittlement temperature is measured according to JIS K7216, and the touch drying time is measured according to JIS K5600-1-1. The viscosity of the primer means the viscosity at 20 ° C. measured using a B-type viscometer.

According to the present invention, not only when the surface layer of a concrete structure is in a dry state, but also when it is in a wet state, it can be applied in a short time at a temperature of -5 ° C to + 40 ° C. It is possible to construct a concrete surface structure that can follow the displacement of the substrate, can withstand considerable stress, and can hold the peeled piece. Specifically, a concrete surface structure showing a maximum stress of 1.5 kN or more at a displacement of 10 mm or more in a punching test, which is a test method of the Japan Highway Public Corporation shown in Examples below, when measuring up to 50 mm displacement. The body can be built. Such a surface structure can also exhibit sufficient concrete peeling prevention performance within a temperature range of about −20 to + 60 ° C. Furthermore, since it has waterproof performance and high permeation resistance such as water vapor, chlorine ion, carbon dioxide gas, it is possible to suppress chemical deterioration of the concrete frame. For example, in such a surface structure, water leakage is not recognized in the water-imperviousness test specified in Japan Highway Public Research Institute Standard JHERI410-15, and the chlorine ion permeation amount in the salt-insulating test is 5.0 × 10 ⁻³ mg / cm ² · day or less, neutralization depth in neutral inhibition test is 0.5 mm or less, oxygen transmission amount by oxygen transmission inhibition test is 2 × 10 ⁻² mg / cm ² · day or less, water vapor transmission The amount of water vapor permeation by the inhibition test can be 5.0 mg / cm ² · day or less. Accordingly, the present invention provides a bridge structure such as a wall rail or outer surface of a superstructure of a bridge, a lower surface of a floor plate and a lower surface of a main girder, a lower surface and a side surface of a pier, in particular, an overhang portion, an inner space of a culvert and a concrete portion of other structures It can be suitably used for a concrete structure such as a floor plate lower part, a concrete beam, a concrete side wall, a concrete dam, a concrete sabo dam, a tunnel, or a building.

Concrete surface structure of the present invention, the surface layer of the concrete structure as described above, the tensile strength of 1N / mm ² or more, preferably a 1.5 N / mm ² or more epoxy resin primer layer, a tensile strength of 7N / A polyurethane or polyurea layer having a thickness of mm ² or more, preferably 10 N / mm ² or more and a tensile elongation at break of 50 to 800%, preferably 100 to 500%, is laminated.

  As the primer layer, an epoxy resin primer is used because it penetrates into the concrete surface layer and adheres firmly to the concrete base and the polyurethane or polyurea layer and develops the above physical properties. Even when the concrete surface is in a wet state, it is preferable to use the epoxy resin primer and the silane coupling agent in combination, since the same physical properties can be expressed.

  Examples of the epoxy resin primer that can be used for the above purpose include a two-component type composed of a main agent (liquid A) mainly composed of an epoxy resin and a liquid B mainly composed of the curing agent. And in the composition after mixing both liquids, the viscosity at 20 ° C. measured by a B-type viscometer is preferably in the range of 20 to 5000 mPa · s, particularly 50 to 3000 mPa · s. When the viscosity of the composition after mixing both liquids is too small, dripping at the time of application becomes remarkable, and workability deteriorates. On the other hand, when the viscosity becomes too large, the permeability to the concrete surface layer becomes insufficient, and it becomes difficult to obtain a strong adhesive surface.

  As A liquid, the reactive diluent, thixotropy imparting agent, surface tension reducing agent, coupling agent, etc. are mix | blended with the epoxy resin which is a main ingredient as needed.

  The epoxy resin used for the liquid A includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, phenol / novolak type epoxy resin, cresol / novolac type epoxy resin, glycidylamine resin, cyclic fat Group epoxy resins, glycidyl ester resins, heterocyclic epoxy resins, bromine-containing epoxy resins, and the like. Among these, it is preferable to use a bisphenol F type epoxy resin alone, but a bisphenol F type epoxy resin and another epoxy resin can also be used in combination.

  As the reactive diluent that can be blended in the liquid A, mono- or polyglycidyl ethers of polyhydric alcohols are preferred, ethylene glycol mono- or diglycidyl ether, polyethylene glycol mono- or diglycidyl ether, neopentyl glycol mono- or di- Glycidyl ether, 1,6-hexanediol mono- or diglycidyl ether, mono- or diglycidyl ether of long-chain alkylene glycol having 8 or more carbon atoms, or even 10 or more, glycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, etc. Can be mentioned. Other reactive diluents include olefin oxides such as octylene oxide, butyl glycidyl ether, styrene oxide, phenyl glycidyl ether, p-butylphenol glycidyl ether, cresyl glycidyl ether, 3- (pentadecyl) phenyl glycidyl ether, glycidyl. Low viscosity mono- or polyepoxy compounds including monoepoxy compounds such as methacrylate, allyl glycidyl ether, cyclohexene vinyl monooxide, dipentene monooxide, α-pinene oxide, and alcohols having reactive groups such as furfuryl alcohol And the like.

  Thixotropy imparting agents that can be used for liquid A include silicic acid-based (fine particulate silicic acid or fumed silica), hydrous silicon magnesium-based (sepiolite, chrysostyle, etc.), aluminum silicate-based (montmorillonite-based bentonite, zeolite, etc. ), Inorganic compounds such as organic bentonite with organic molecules adsorbed between layers, polyhydroxycarboxylic acid or its amides, polyacrylic acid soda, dibenzal sorbite, certain surfactants, etc. Examples of these organic compounds can be given.

  Examples of the surface tension reducing agent that can be used for the liquid A include polyhydroxycarboxylic acid amide, silicone-modified polyacrylate, polysiloxane, and the like. Since some of the thixotropic properties-imparting agents have a surface tension lowering effect, the thixotropic properties-imparting agent can also be used as a surface tension reducing agent.

  Examples of coupling agents that can be blended in the liquid A include titanium coupling agents, silane coupling agents, aluminum coupling agents, zirconium coupling agents, chromium coupling agents, and organic phosphate coupling agents. The use of a silane coupling agent is preferred. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxyethoxy) silane, methacryloxytrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycine. Contains unsaturated groups or epoxy groups such as sidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane A silicon compound etc. can be mentioned. Among these, the use of a silane coupling agent having an epoxy group is preferable because a primer layer having excellent characteristics can be formed even when the concrete surface layer is in a wet state.

  For example, when the total amount of the epoxy resin and the reactive diluent is 100 parts by weight, the proportion of the epoxy resin is 60 to 100 parts by weight, preferably 65 to 90 parts by weight. The diluent is 40 to 0 parts by weight, preferably 35 to 10 parts by weight. The total amount of the epoxy resin and the reactive diluent is 100 parts by weight, and the thixotropic agent is 0 to 10 parts by weight. The ratio can be such that the tension reducing agent is 0 to 3 parts by weight and the coupling agent is 0.1 to 5 parts by weight.

  The liquid B constituting the epoxy resin primer includes aliphatic primary amines (aliphatic diamines, aliphatic polyamines, aromatic ring-containing aliphatic polyamines, alicyclic polyamines, cyclic polyamines, etc.), aromatic primary amines, tertiary amines. Curing agents, phosphorus-containing or halogen-containing amine curing agents, lower alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof are reacted with ammonia to react hydroxyl groups at the end of the polyether with amino groups. Polyether polyamines such as polyoxyethylene diamine, polyoxypropylene diamine, polyoxybutylene diamine, etc. obtained by substituting with, or adducts of epoxy compounds of these amine curing agents, adducts of acrylonitrile or Mannich additions Such as amine-based curing agents such as modified products, polyaminoamide-based curing agents, aliphatic carboxylic acid anhydrides, alicyclic carboxylic acid anhydrides, and aromatic carboxylic acid anhydrides, etc. A curing agent is used as the main component. Preferred curing agents include aliphatic polyamines, aromatic ring-containing aliphatic polyamines, alicyclic polyamines, or modified polyamines obtained by subjecting them to the above-described modification. These polyamine curing agents may be used alone or in combination of two or more.

  The above-described thixotropy-imparting agent, surface tension reducing agent, coupling agent, and the like can also be added to the B liquid containing the above curing agent as a main component. For example, amino group-containing silicon compounds such as γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane as coupling agents Mercapto group-containing silicon compounds such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane can be blended.

  Further, one or both of the liquid A and the liquid B may contain additives for reducing viscosity or improving compatibility, including a plasticizer and a softening agent, as necessary. In addition, various additives used for the epoxy resin adhesive may be contained.

  In applying the epoxy resin primer to the surface of the concrete structure, liquid A and liquid B are mixed. The blending ratio of liquid A and liquid B depends on the type of epoxy resin and curing agent used and their contents, but the optimum amount determined experimentally based on the required amount based on the ratio of epoxy equivalent / active hydrogen equivalent. For example, it can be used at a ratio of 10 to 100 parts by weight, particularly 20 to 80 parts by weight with respect to 100 parts by weight of the A liquid.

  By appropriately selecting the type and blending amount of the epoxy resin, the curing agent, or other additives, the viscosity at 20 ° C. after mixing of the liquid A and the liquid B is 20 to 5000 mPa · s, preferably 50 to 3000 mPa · s. It is preferable to prepare as follows. In this case, it is preferable to use a solventless type that does not use an organic solvent as a diluent for both the A liquid and the B liquid. That is, in general, an organic solvent is often used for the purpose of adjusting the viscosity. However, in the case of using an organic solvent, in order to prevent it from remaining in the primer layer, a sufficient amount of solvent is diffused after applying the primer. This is because if time is not taken, problems such as swelling may occur. In particular, when the construction is performed at a low temperature, it is necessary to secure a sufficient time for the solvent to be diffused, resulting in a problem that the construction time becomes long.

  As an epoxy resin primer, when applied to a concrete structure surface layer in a wet state, at least a part of the epoxy resin and / or curing agent having a hydrophilic group such as a polyether skeleton is used. It is good to use for. A primer layer having a desired tensile strength can be formed by applying such a mixed solution to the surface of the concrete structure by means of brushing or the like. The layer thickness of the primer layer is preferably about 0.02 to 0.4 mm. By having such a primer layer, the concrete structure and the polyurethane or polyurea layer can be firmly adhered, and by making a polyurethane or polyurea and a laminated structure to be described later, in the range of -20 to 60 ° C, A surface structure that can follow the displacement of the concrete piece and withstand the corresponding stress can be formed.

The polyurethane or polyurea used in the concrete surface structure of the present invention has a tensile strength of 7 N / mm ² or more, preferably 10 N / mm ² or more, and a tensile breaking elongation of 50 to 800%, preferably 100 to 500%. It is. As the polyurethane or polyurea, those having a brittle temperature of −25 ° C. or lower, particularly −30 ° C. or lower are preferable. By using the above-mentioned properties as polyurethane or polyurea, it is possible to form a surface structure capable of following the displacement of the concrete piece and withstanding the corresponding stress in the range of -20 to 60 ° C. it can.

  Specifically, the polyurethane or polyurea can be formed by mixing a urethane prepolymer having two or more isocyanate groups and a curing agent having two or more hydroxyl groups and / or amino groups.

  Such a urethane prepolymer can be obtained by reacting a polyisocyanate compound having two or more isocyanate groups in one molecule with a compound having two or more active hydrogens reacting with the isocyanate group in one molecule. it can. Particularly preferred as the active hydrogen compound is a urethane prepolymer formed by combining one or two or more polyol compounds having two or more alcoholic hydroxyl groups in one molecule, such as polyether polyol, polyester polyol or other polyols. It is.

  Examples of the polyisocyanate compound that can be used for the preparation of the urethane prepolymer include aliphatic polyisocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine methyl ester diisocyanate; 1,4-cyclohexane diisocyanate, isophorone Cycloaliphatic polyisocyanates such as diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hydrogenated tolylene diisocyanate, norbornane diisocyanate; p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 3,3 Aromatic diisocyanates such as' -dimethyldiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate Aromatic polyisocyanates and the like; such that each of the above-mentioned polyisocyanate and carbodiimide-modified or isocyanurate-modified, and these may be used alone or as a mixture of two or more. Preferably, aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 4,4'-diphenylmethane diisocyanate are used from the viewpoint of easy handling.

  Specific examples of polyether polyols that can be used for the preparation of urethane prepolymers include polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethyleneoxypropylene glycol, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, and the like. , Low molecular weight active hydrogen compounds having two or more active hydrogens, for example, diols such as bisphenol A, ethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol; glycerin, trimethylolpropane, 1,2,6- Triols such as hexanetriol; propylene oxide and / or in the presence of one or more amines such as ammonia, methylamine, ethylamine, propylamine, butylamine, etc. It can be mentioned random copolymer obtained by the Chi alkylene oxide by ring-opening polymerization.

  Examples of polyester polyols that can be used to prepare urethane prepolymers include polymers obtained by dehydration condensation of polybasic acids and polyhydric alcohols; condensates of hydroxycarboxylic acids and polyhydric alcohols; ring-opening polymers of lactones, etc. Are preferably used. Examples of the polybasic acid include adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, succinic acid, dimerized linolenic acid, maleic acid, and the like. Examples of the polyhydric alcohol include bisphenol A, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neo Diols such as pentyl glycol; triols such as glycerin, 1,1,1-trimethylolpropane, and 1,2,6-hexanetriol can be used. More specifically, polyethylene adipate, polytetramethylene adipate, polyhexamethylene adipate, polytetramethylene sebacate, poly (diethylene glycol adipate), poly (hexamethylene glycol-1,6-carbonate) whose both ends are diol components ), Polycaprolactone and the like.

  Other polyols that can be used to prepare the urethane prepolymer include, for example, acrylic polyols, hydrogenated polybutadiene polyols, castor oil derivatives, tall oil derivatives, polymer polyols, polycarbonate polyols, ethylene glycol, diethylene glycol, Low molecular polyols such as propylene glycol, dipropylene glycol, butanediol, pentanediol and hexanediol are also preferably used.

  These polyol compounds preferably have a number average molecular weight of 100 to 10,000, particularly 300 to 5,000, and can be used alone or in combination of two or more as desired.

  In the urethane prepolymer, the ratio of the isocyanate group contained in the polyisocyanate compound to more than 1 mole with respect to 1 mole of the hydroxyl group contained in the polyol compound, that is, the chemical equivalent ratio (NCO / OH) exceeds 1. As a formulation, the polyol compound and the polyisocyanate compound can be obtained by heating and reacting as necessary. Such urethane prepolymers usually have isocyanate groups at both molecular ends. As a urethane prepolymer, a polyol compound and a polyisocyanate compound are mixed at a ratio of 1.6 to 20 at a chemical equivalent ratio (NCO / OH) of a hydroxyl group contained in the polyol compound and an isocyanate group contained in the polyisocyanate compound. What reacts and exhibits liquid state at 23 degreeC is more preferable from points, such as workability | operativity and the physical property of hardened | cured material.

  The polyurethane or polyurea forming the concrete surface structure of the present invention can be formed by curing a curable composition in which a curing agent and, if necessary, other additives are blended with the urethane prepolymer. Examples of the curing agent that cures the urethane prepolymer include compounds having two or more active hydrogens that react with isocyanate groups in one molecule. As such a compound, a low molecular weight compound having a molecular weight of 18 to 3000, preferably 30 to 300 is preferable, for example, water; ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene. Glycol, 1,6-hexylene glycol, glycerin, trimethylolpropane, 1,2,4-trihydroxybutane, 1,2,3,4-tetrahydroxybutane, 1,2,6-trihydroxyhexane, 1, Polyhydric alcohols such as 1,1-trimethylolethane, pentaerythritol, polycaprolactone, fructose, xylitol, arabitol, sorbitol and mannitol; low molecular amino alcohols such as ethanolamine; ammonia, hydrazine, ethylenediamine, diethylenetri Min, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, m-phenylenediamine, 2,4-tolylenediamine, 2,6-tolylenediamine, diethyltolylenediamine, 3,3'-dichloro-4 Low molecular weight polyamine compounds such as 4'-diamino-diphenylmethane, and polyols such as polyether polyols and polyester polyols that can be used in the preparation of the urethane prepolymers listed above; ethylene oxide, propylene oxide, butylene oxide, etc. Polyoxyethylene diamine and polyoxypropylene dia obtained by reacting a hydroxyl group having a polyether terminal obtained by reacting an alkylene oxide or a mixture thereof with an ammonia group by reacting with ammonia Emissions, may be mentioned polyether polyamines such as polyoxybutylene diamine. Among these curing agents, it is preferable to use polyether polyol or polyether polyamine, but it is also possible to use polyether polyol or polyether polyamine in combination with one or more other low molecular polyols or low molecular polyamines. it can. When these curing agents are other than water, the active hydrogen in the low molecular weight compound is in a ratio of about 0.8 mol or more, preferably about 0.95 with respect to 1 mol of the isocyanate group contained in the urethane prepolymer. A curing agent is added so that it will be -1.2 mol.

  In addition to the urethane prepolymer and the curing agent, examples of additives that can be optionally blended include plasticizers, surfactants, pigments, dyes, fillers, curing accelerators, and anti-aging agents. .

  Plasticizers include carboxylic acid esters such as phthalic acid esters, adipic acid esters, sebacic acid esters, azelaic acid esters, trimellitic acid esters, phosphate esters, normal paraffins, chlorinated paraffins, alkylbenzenes, and other various liquid components. These may be used alone or in combination of two or more.

  As the surfactant, various surfactants may be added singly or in combination of two or more according to properties such as an antifoaming agent, a wetting and dispersing agent for pigments and fillers, an emulsifier, and a viscosity modifier.

  In order to color the cured product, organic pigments such as azo pigments and copper phthalocyanine pigments, and various inorganic pigments such as carbon black, zinc oxide, zinc sulfide, chromium oxide, and bengara can be used as the pigment.

  Examples of the filler include calcium carbonate, magnesium oxide, clay, talc, silica, diatomaceous earth, and those treated with a surface treatment agent such as fatty acid or fatty acid ester.

  As a curing accelerating catalyst for accelerating the reaction between the urethane prepolymer and the curing agent, N-alkylbenzylamine, N-alkyl aliphatic polyamine, triethylenediamine, N-alkylpiperazine, N-alkylmorpholine, dimorpholinodiethyl ether, Examples include organometallic compounds such as tin octenoate and dibutyltin dilaurate, and these may be used alone or in combination of two or more.

  Anti-aging agents are used to protect polyurethane or polyurea layers from light, oxygen, heat, etc., and those commonly used as anti-aging agents include light stabilizers and antioxidants, Examples of the agent include benzotriazole, benzophenone, benzoate, cyanoacrylate, hindered amine, and nickel. Antioxidants include hindered phenols, amines, sulfurs, phosphoruss and the like.

  The concrete surface structure of the present invention is obtained by applying a curable composition comprising the urethane prepolymer, a curing agent, and an optional additive to the epoxy resin primer layer formed on the concrete structure. It is constructed by forming a layer of 0.8-4 mm, preferably 1-3 mm of polyurethane or polyurea by curing. The coating method can be performed by any method such as spray coating or brush coating, but spray coating is preferable because it can be applied in a short time. A curable composition comprising a urethane prepolymer, a curing agent, and an additive that is optionally blended, when considering application workability, is applied manually or by a method equivalent to this without using a spray device such as a trowel. Is preferably prepared so that the viscosity at 23 ° C. is about 500 to 2000 mPa · s. In addition, by selecting the molecular weight of the urethane prepolymer, the type of curing agent and curing accelerator, the amount added, etc., the touch drying time specified by JIS K5600-1-1 at 23 ° C. is a two-component collision mixed spray. When using an apparatus, it is preferable to prepare it so that it may be 1 to 120 seconds, and when it is applied manually or according to a method corresponding thereto, it is 10 to 200 minutes. Furthermore, the tensile strength, tensile elongation at break, embrittlement temperature and the like can be adjusted to desired values depending on the type of urethane prepolymer and curing agent and the type and amount of other additives.

  The concrete surface structure of the present invention can exhibit a sufficient peeling prevention effect without using a fiber sheet by using a laminated structure of the epoxy resin primer layer and the polyurethane or polyurea layer as described above. it can. Specifically, a concrete surface structure showing a maximum stress of 1.5 kN or more at a displacement of 10 mm or more in a punching test, which is a test method of the Japan Highway Public Corporation shown in Examples below, when measuring up to 50 mm displacement. It can be a body.

  For the purpose of imparting the weather resistance and other properties of the surface structure constructed as described above, a topcoat layer may be provided on the surface of the polyurethane or polyurea layer. As such a topcoat layer, a fluororesin, an acrylic silicon resin, an acrylic urethane resin, an acrylic resin, or a modified resin thereof can be used. For example, it is effective to form the top coat layer to a thickness of about 0.05 to 0.4 mm. For the purpose of protecting the polyurethane or polyurea layer, the thickness is about 2 mm or less, preferably about 1 to 2 mm, directly or via a primer layer on the surface of the polyurethane or polyurea layer or on the surface of the topcoat layer. A protective layer can be provided. The protective layer may be any material as long as it has good adhesion to the polyurethane or polyurea layer, does not deteriorate in a normal repair cycle, and serves the purpose of protecting the surface structure. The same material as polyurea can be used. In this case, when the protective layer is removed by refurbishment, it is preferable to color both of them in different colors so that the difference between the polyurethane or polyurea layer and the protective layer in the surface structure becomes clear. When such a protective layer is provided, a top coat layer as described above can be further provided thereon.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
<Preparation of primer>
100 parts by weight of liquid bisphenol F-type epoxy resin (trade name: Adeka Resin R4901, manufactured by Asahi Denka Kogyo Co., Ltd.) and 0.5 parts by weight of γ-glycidoxypropyltrimethoxysilane are mixed and stirred thoroughly with a stirrer. Used as the main primer.
A liquid amine curing agent (trade name: Daitokural I-5476, manufactured by Daito Sangyo Co., Ltd.) was used as a primer curing agent.

<Measurement of primer properties>
When 50 parts by weight of the curing agent was blended with 100.5 parts by weight of the primer main component and stirred to obtain a uniform blend, the viscosity at 20 ° C. was immediately measured with a B-type viscometer. s. The same compound was poured into a mold and cured to prepare No. 2 dumbbell as defined in JIS K7113. The tensile strength was 32 N / mm ² when the tensile properties were measured with a testing machine in accordance with JIS K7113 on the 7th day of material age.

<Measurement of properties of polyurethane>
Polyurethane resin for two-component spray (trade name: Rim Spray F1000, finger touch drying time 13 seconds (23 ° C.), manufactured by Mitsui Chemicals Co., Ltd.), two-component collision mixing sprayer (H-2000 / GX7) A 2 mm thick sheet was obtained by spraying onto an aluminum plate using a spray gun (manufactured by GUSMER). Seven days later, a No. 3 dumbbell defined in JIS K6251 was produced by punching. On the 7th day of material age, tensile properties were measured with a testing machine in accordance with JIS K6251. As a result, the tensile strength was 12 N / mm ² , and the tensile elongation at break (between the marked lines) was 370%. Similarly, using a test piece prepared from a sheet, the embrittlement temperature was measured according to JIS K7216 on the 7th day of the material age, and it was -53 ° C.

<Punching test>
A cylindrical groove of φ100 mm was formed at a depth of 55 mm with a concrete core cutter at the center of a reinforced concrete U-shaped lid (400 × 600 × 60 mm) defined in JIS A5334. Next, the opposite surface on which the groove was formed was sufficiently polished with # 150 abrasive paper defined by JIS B6252, and then immersed in water at 20 ° C.

After taking out from water 24 hours later, the U-shaped lid was placed with the polished surface up and immersed in water 30 mm from the lower end, and water droplets on the surface were removed with a waste cloth. The primer prepared by mixing the main agent and the curing agent was applied to the polished surface after 3 minutes with a roller in an amount of 200 g / m ² in an area of 400 × 400 mm in the center. Two weeks later, the polyurethane resin (rim spray F-1000) was sprayed on the primer-coated surface with a sprayer so as to have an average thickness of 2 mm while being semi-immersed in water.

  After holding for 7 days, the U-shaped lid is placed on the H steel with the coating surface facing down so that the span is 400 mm (Shimadzu Universal Testing Machine UH-I, manufactured by Shimadzu Corporation) And loaded with a ball seat in the center of the inner core of the cylindrical groove. First, load at a speed of 1 mm / min until the lower part of the U-shaped lid core breaks, and after confirming that it has broken beyond the initial stress peak, load at 5 mm / min. The relationship between displacement and stress up to 50 mm displacement was recorded. As a result, the maximum stress of 3.2 kN was shown when the displacement was 50 mm.

[Example 2]
In Example 1, a series of coating and holding was performed in a state where the U-shaped lid was dry, and a punching test was performed. As a result, the maximum stress of 3.4 kN was shown at 50 mm displacement.

[Example 3]
In Example 1, instead of polyurethane resin (rim spray F-1000), polyurea resin (trade name: SWAIRE AR-100, finger touch drying time 5 seconds (23 ° C.), manufactured by Mitsui Chemicals, Inc.) A test specimen was produced by spraying with the same spray apparatus as in Example 1, and a punch test was conducted. As a result, the maximum stress of 6.2 kN was shown when the displacement was 50 mm.
The tensile properties of the polyurea resin were as follows: the tensile strength was 24 N / mm ² , the tensile elongation at break (between the marked lines) was 200%, and the embrittlement temperature was −55 ° C.

[Comparative Example 1]
In Example 1, instead of polyurethane resin (Rimspray F-1000), epoxy resin (trade name: Silical EC1, manufactured by Mitsui Chemicals, Inc.) was applied with 2 mm with a rubber spatula to prepare a test specimen. A push-out test was performed. As a result, after showing the maximum stress at the time of displacement of 5 mm, the coating film was destroyed, and thereafter the stress was rapidly reduced to 0.2 kN or less.

[Comparative Example 2]
In Example 1, a test specimen was prepared using an acrylic primer (trade name: Silical MP2, tensile strength 30 N / mm ² , manufactured by Mitsui Chemicals, Inc.) instead of the primer used therein, and punched out. The test was conducted. As a result, the maximum stress of 0.9 kN was observed at the time of 15 mm displacement, and after that there was no sudden stress drop, but no further stress increase was observed.

Claims (9)

The surface layer of the concrete structure, and the tensile strength of 1N / mm ² or more epoxy resin primer layer, a tensile strength of 7N / mm ² or more, the thickness tensile breaking elongation is 50-800% of 0.8~4mm polyurethane Or a concrete surface structure in which polyurea layers are laminated.   The concrete surface structure according to claim 1, wherein the epoxy resin primer contains a silane coupling agent.   The concrete surface structure according to claim 2, wherein the silane coupling agent is a silane coupling agent having an epoxy group.   The concrete surface structure according to claim 1, wherein the polyurethane or polyurea has a brittle temperature of -25 ° C or lower.   5. The concrete surface structure according to claim 1, wherein a top coat layer and / or a protective layer made of polyurethane or polyurea having a thickness of 2 mm or less is further provided on the polyurethane or polyurea layer. An epoxy resin primer having a viscosity in the range of 20 to 5000 mPa · s and a tensile strength at curing of 1 N / mm ² or more is applied to the surface layer of the concrete structure, and the tensile strength at curing is 7 N / A concrete surface structure characterized by forming a polyurethane or polyurea layer having a thickness of 0.8 to 4 mm by spraying a curable composition of polyurethane or polyurea having a thickness of mm ² or more and a tensile elongation at break of 50 to 800%. How to build.   The method for constructing a concrete surface structure according to claim 6, wherein the epoxy resin primer is a solvent-free epoxy resin primer containing a silane coupling agent in a proportion of 0.1 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin primer.   The method for constructing a concrete surface structure according to claim 6 or 7, wherein the surface layer of the concrete structure is in a wet state.   9. The method for constructing a concrete surface structure according to claim 6, wherein a polyurethane or polyurea curable composition having a touch drying time of 1 to 120 seconds is used.