JP2011099209A - Construction method for preventing concrete from falling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method for preventing concrete from falling, which prevents a concrete construction from falling, greatly reduces the amount of organic solvents discharged into the environment as environmentally friendly, and hardly generates toxic gas in case of fire. <P>SOLUTION: This construction method for preventing the concrete from falling is characterized as follows: the surface of the concrete structure is coated with bonding polymer cement mortar and a mesh-like sheet; and the coated surface is coated with a water-based coating. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a concrete exfoliation preventing method for concrete structures, and particularly a concrete exfoliation preventing method that exhibits excellent performance in a tunnel or a concrete part that is a closed space such as a multi-level parking lot.

  Concrete structures such as viaducts, tunnels, bridges, and buildings are widely used because of their excellent strength and durability. However, in recent years, concrete has deteriorated due to corrosion of steel bars due to salt damage, neutralization by exhaust gas, alkali-aggregate reaction, freezing of moisture that has penetrated into cracks, etc., and as the deterioration progresses, concrete pieces peel off from the surface. Problems such as a decrease in strength of the concrete structure itself and a loss of aesthetics are occurring. In addition, the danger of accidents due to falling concrete pieces has been pointed out.

  For this reason, countermeasures such as prevention of concrete deterioration and flaking are performed by various methods. For example, in order to reduce the temperature change of the concrete surface and prevent cracking of the concrete surface, a method of forming a heat-radiating heat-insulating coating film on the concrete surface has been proposed (see, for example, Patent Document 1).

  In addition, when a crack occurs on the surface of a concrete structure, a method of forming a flexible coating film that covers the crack is also proposed (for example, see Patent Document 2).

  As a method for preventing peeling of concrete, a method is known in which a high-strength coating film is formed on the concrete surface, and a coating film is formed thereon by applying a coating (see, for example, Patent Document 3). Moreover, the method of sticking a continuous fiber sheet on the surface of a concrete structure with an adhesive, and preventing peeling is also known (for example, refer nonpatent literature 1).

  However, when an organic solvent-based paint is used, the organic solvent (VOC) is volatilized during painting, and the working environment at the time of painting becomes worse, particularly in a closed place such as in a tunnel. There is also a problem that VOCs are released into the environment from the natural environment and cause air pollution. Furthermore, in a closed space, it is necessary to consider the effects of gas generated during a fire on the human body and the spread of fire during a fire.

JP 2000-95584 A JP 2005-35827 A JP 2005-15329 A JP-A-6-298910

Structural paint group Takayuki Sato, Go Miyashita, “Concrete flaking prevention method” DNT coating technical report, Dainippon Paint Co., Ltd., October 2002, No. 2, 10-15 pages

  The object of the present invention is to solve such problems, and has a performance to prevent the concrete structure from peeling off, and the amount of organic solvent discharged into the environment is extremely low. It is to provide a concrete exfoliation prevention method with little generation of toxic gas.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that the above problems can be achieved by the following configuration, and have achieved the present invention.

  According to the present invention, there is provided a concrete peeling prevention method characterized in that a concrete structure surface is coated with an adhesive polymer cement mortar and a mesh-like sheet on the concrete structure, and then coated with a water-based paint. .

  The present invention provides an environment-friendly concrete exfoliation prevention method that has an anti-peeling performance for concrete structures and has an extremely small amount of organic solvent discharged into the environment.

  Moreover, since an organic solvent is not used for construction, the load on the human body during construction can be reduced, and the occurrence of fire can be suppressed.

  Further, by using an inorganic coating as the water-based coating, non-flammability can be imparted to the coating film, and no toxic gas is generated even in the event of a fire. In particular, it is effective for preventing concrete pieces from being removed in a closed space such as a tunnel inner wall or a multilevel parking lot.

  Hereinafter, the concrete peeling prevention method of the present invention will be described in detail.

  First, each component used for this invention is demonstrated.

(A) About polymer cement mortar The polymer cement mortar for adhesion used in the present invention is obtained by adding a polymer (resin) as a binder to cement, and is widely used for improving physical properties and workability. Yes. The polymer cement mortar used in the present invention preferably has good workability when applying concrete unevenness and good workability when applying a mesh sheet. Moreover, the thing which shows the sclerosis | hardenability at the time of low temperature, and exhibits intensity | strength about 7 days after construction is preferable.

  This polymer cement mortar is usually composed of cement and aggregate, resin, hardener and the like. Among these, as the cement, various types of cement generally employed in polymer cement mortar can be arbitrarily used without any particular limitation. As an example of such a cement, for example, a hydraulic cement can be preferably cited. Examples of such hydraulic cement include Portland cement, alumina cement, white cement, lime mixed cement, blast furnace cement, colloidal cement, silica cement, fly ash cement, slag cement, and the like. These cements may be used alone, or two or more of these cements may be used in combination. For example, a combination of Portland cement and alumina cement is preferable.

Cement is used as a powder, and its specific surface area is suitably, for example, 3000 to 6000 cm ² / g when measured by a specific surface area test of JIS R5201.

  The cement is generally blended in an amount of 10 to 60% by mass, preferably 20 to 50% by mass, based on the amount of the polymer cement mortar.

  As the aggregate, various aggregates that have been generally employed in polymer cement mortars can be arbitrarily used without particular limitation. Preferred examples of such aggregates include quartz sand, river sand, stone crushed materials, porcelain crushed materials, glass crushed materials, glass beads, and lightweight aggregates. The aggregate may be used alone, or may be used as a mixture of two or more. The size of the aggregate is 0.3 mm (lattice diameter) when the residual amount on the sieve is 30% by mass or less and 0.15 mm (lattice diameter) on the sieve when expressed in terms of the residual amount of sieve specified in JIS A1102. It is preferable that the residue is 70% by mass or less, the residue on the 0.3 mm (lattice diameter) sieve is 0%, and the residue on the 0.15 mm sieve is 30% by mass or less.

  It is appropriate that the aggregate is generally 10-80% by weight, preferably 30-50% by weight, based on the amount of polymer cement mortar.

  As the polymer cement mortar used for the ground treatment of the concrete structure and the unevenness adjustment, resins such as acrylic resin, SBR resin, and epoxy resin are generally used. For the polymer cement mortar used in the present invention, various resins can be arbitrarily used without any particular limitation.

  The resin to be used is preferably a hydrophobic and liquid type epoxy resin (here, hydrophobic means that it does not dissolve in water or has no hydrophilicity, for example, as solubility in water) 3% or less soluble). When a hydrophobic liquid epoxy resin is used, since it is a hydrophobic resin, water resistance is improved as a physical property after curing.

  Among them, a preferable epoxy resin is an epoxy resin that is liquid at normal temperature (20 to 25 ° C.). The hydrophobic liquid epoxy resin preferably has an epoxy equivalent of 120 to 300 g / eq, more preferably 150 to 210 g / eq. If the epoxy equivalent is less than 120 g / eq, the physical strength decreases, which is not preferable. On the other hand, if the epoxy equivalent is an excessive value exceeding 300 g / eq, the resin cannot be maintained generally at a low temperature of about 5 ° C., and the resin crystallizes and precipitates.

  Such a hydrophobic liquid epoxy resin is not particularly limited as long as it reacts with a curing agent at room temperature to be cured. The epoxy resin preferably contains one or more, preferably 1.2 or more glycidyl groups in the molecule.

  Examples of the epoxy resin that can be used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, alkyl monoglycidyl ether, alkyl monoglycidyl ester, alkyl diglycidyl ether, alkyl diglycidyl ester, alkylphenol monoglycidyl ether, Examples include polyglycol monoglycidyl ether and polyglycol diglycidyl ether. Here, the alkyl group in the alkyl monoglycidyl ether or the like is preferably, for example, an alkyl group having 3 to 15 carbon atoms.

  As such an alkyl group, for example, an alkyl group such as a neopentyl group and a 2-ethylhexyl group is preferably exemplified. Such epoxy resins may be used alone or as a mixture thereof. In this case, the epoxy equivalent of the mixture of the epoxy resin as a whole should just be in said range.

  As a hardening | curing agent used by this invention, the various hardening | curing agents generally used as a hardening | curing agent of an epoxy resin can be arbitrarily used without being specifically limited. A curing agent that can be preferably used is a water-soluble amine resin curing agent, which is water-soluble and incorporates a hydrophobic liquid epoxy resin when polymer cement mortar is prepared.

  The water-soluble amine resin curing agent shows a transparent property at room temperature in a situation where there are many resin components and little dilution water (60% or more in the heating residue). As a water-soluble amine resin hardening | curing agent, the water-soluble amine resin hardening | curing agent shown by patent document 4 is mentioned suitably, for example.

  The water-soluble amine resin as a curing agent is preferably used in an equivalent ratio with respect to the epoxy equivalent of the hydrophobic liquid epoxy resin, for example, 0.50 to 1.50, preferably 0.85 to 1.30. It is. Moreover, a hardening | curing agent may be used independently and may be used as a mixture.

  In the polymer cement mortar used in the present invention, an inorganic powder, a water retention agent, a fluidizing agent, a setting modifier or the like can be blended as necessary.

  The inorganic powder is blended in order to prevent sagging during construction of the polymer cement mortar and to improve the iron finish. Suitable examples of such inorganic powder include blast furnace slag powder, blast furnace slag fine powder, fly ash, classified fly ash, silica fume, calcium carbonate powder, stone powder, diatomaceous earth, kaolin, bentonite, and sepiolite. These inorganic powders may be used alone or as a mixture thereof. The inorganic powder is preferably 2 to 10% by mass, more preferably 2 to 7% by mass, based on the amount of the polymer cement mortar.

  The fluidizing agent is blended in order to improve the fluidity of the polymer cement mortar and improve the workability without increasing the amount of water. As the fluidizing agent, for example, a high performance water reducing agent, a high performance AE water reducing agent, a water reducing agent, or the like can be used. In particular, as the fluidizing agent, commercially available naphthalene sulfonate-based, melamine sulfonate-based, polycarboxylate-based, and lignin sulfonate-based fluidizing agents are preferably exemplified. The fluidizing agent is preferably blended at 0.01 to 1% by mass, preferably 0.05 to 0.3% by mass, based on the amount of the polymer cement mortar.

  The water retention agent improves the water retention of the polymer cement mortar, prevents water absorption of the moisture in the mortar into the ground concrete, and prevents evaporation of moisture from the mortar, improving workability, , Blended to prevent deterioration of adhesion to the base concrete or top coating material due to cracking, dryout. Preferable examples of the water retention agent include methyl cellulose, methyl ethyl cellulose, hydroxyl propyl cellulose, carboxymethyl cellulose, guar gum, alginate, polyvinyl alcohol, polyacrylic acid, polyethylene oxide, and modified polysaccharide. The water retention agent is, for example, 0.001 to 0.3% by mass, preferably 0.003 to 0.1% by mass, based on the amount of the polymer cement mortar.

  The setting modifier is blended for the purpose of controlling the pot life of the polymer cement mortar when alumina cement is mixed. Preferred examples of the coagulant adjuster include citric acid, tartaric acid, malic acid, gluconic acid, and oxycarboxylic acids such as alkali metal salts thereof. Based on the amount of the polymer cement mortar, the setting modifier is, for example, 0.001 to 0.3% by mass, preferably 0.005 to 0.1% by mass.

  Although the manufacturing method of the polymer cement mortar used by this invention is not specifically limited, A fiber, a pigment, etc. can be used together as needed other than the above.

(B) Mesh sheet The mesh sheet used in the present invention is generally composed of high-strength, high-elasticity fibers, glass fiber, vinylon fiber, polyamide fiber, polyethylene fiber, polyparaphenylene fiber, polyarylate fiber, An aramid fiber, a carbon fiber, etc. can be mentioned. Among these, a mesh sheet made of vinylon resin or polyamide resin, which has excellent load resistance and excellent wettability with polymer cement mortar, is preferably used. Moreover, although there are mesh shapes such as biaxial, triaxial, and tetraaxial as the fiber form, the mesh sheet used in the present invention is a triaxial mesh sheet made of vinylon resin or the like from the viewpoint of strength and cost. A polyamide resin biaxial mesh sheet is preferred. Moreover, as for the magnitude | size (mesh) of the mesh-shaped sheet | seat, one side is 2 mm-15 mm. If the size of the eyes is too large, the peeling prevention effect is lowered.

  The mesh sheet used in the present invention is held on a concrete structure with an adhesive polymer cement mortar, and the polymer cement mortar is cured and the mesh sheet is also fixed. In that case, the unevenness adjustment is appropriately performed using a roller, a trowel, a spatula or the like along the shape of the concrete structure. If foreign matter such as dust or dirt is found on the surface of the concrete structure, clean it with a brush or air blow beforehand.If cracks are found, remove cement mortar or polymer cement mortar. It is desirable to fill in and use holes.

(C) Water-based paint The concrete peeling prevention method of the present invention is coated with a water-based paint on a hardened polymer cement mortar and a fixed mesh sheet. Water-based paints are coated with a coating film for aesthetics, improved luminous reflectance, and antifouling properties, and water-based paints are used to extremely reduce the amount of organic solvent discharged into the environment.

  The water-based paint is preferably a water-based inorganic paint or a water-based organic / inorganic composite paint, particularly in order to suppress the generated gas that adversely affects the human body during a fire and to suppress the spread of fire.

  As the water-based inorganic paint, for example, there is a water-based polysiloxane paint, and the main component thereof is a dispersion of tetraalkoxysilane represented by the following formula or a partially hydrolyzed condensate thereof in water.

Si (OR ¹ ) _x (OR ² ) _(4-x) (1)
In formula (1), ^{R 1} and ^{R 2} is an organic group having 1 to 8 carbon atoms, x is an integer of 0-4.

In the above formula (1), preferred examples of the organic group as R ¹ and R ² include an alkyl group, a cycloalkyl group, and an aryl group. R ¹ and R ² may be the same or different.

  Here, the alkyl group may be linear or branched. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, Examples thereof include alkyl groups such as heptyl group and octyl group. A preferable alkyl group is an alkyl group having 1 to 4 carbon atoms.

  Preferred examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and the like. Examples of the aryl group include a phenyl group.

  Specific examples of the tetraalkoxysilane represented by the above formula (1) include, for example, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and triethoxybutoxysilane. These tetraalkoxysilanes can be used alone or as a mixture of two or more.

These may be a partial hydrolyzed condensate of tetraalkoxysilane, and the weight average molecular weight in terms of polystyrene of the condensate is preferably 300 to 5,000, particularly 500 to 3,000. By using the product, a coating film having good adhesion can be obtained without deteriorating storage stability. Moreover, the partial hydrolysis-condensation product of tetraalkoxysilane is suitable to have one or more, preferably 3 to 30, —OH groups, —OR ¹ groups, or —OR ² groups bonded to silicon atoms.

  Specific examples of such condensates include commercially available products such as ethyl silicate 40 and ethyl silicate 56 (both manufactured by Colcoat).

  Examples of water-based organic / inorganic composite coatings include those containing organosilane and / or its partial hydrolysis-condensation products, and organic-inorganic composite resins obtained by hydrolytic condensation reaction of these with, for example, silyl group-containing vinyl resins. There are water-based paints included as agents.

  Organosilane and / or its partial hydrolysis condensate is generally represented by the following formula.

R ³ _n Si (OR ⁴ ) _4-n (2)
In formula (2), ^{R 3} is an organic group having 1 to 8 carbon atoms, ^{R 4} is an alkyl group having 1 to 5 carbon atoms, and, n is an integer from 0 to 2.

In the above formula (2), examples of the organic group as R ³ include an alkyl group, a cycloalkyl group, an aryl group, and a vinyl group.

  Here, the alkyl group may be linear or branched. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, Examples thereof include alkyl groups such as heptyl group and octyl group. Preferred alkyl groups are those having 1 to 4 carbon atoms. Preferred examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and the like. Examples of the aryl group include a phenyl group.

  Each of the above functions may optionally have a substituent. Examples of such a substituent include a halogen atom (for example, a chlorine atom, a bromine atom, and a fluorine atom), a (meth) acryloyl group, a mercapto group, and an alicyclic group.

The alkyl group as R ⁴ may be linear or branched. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, pentyl group, and the like. And preferred alkyl groups have 1 to 2 carbon atoms.

  Specific examples of the silicate (n = 0) represented by the above formula (2) include ethyl silicate, methyl silicate, diisopropyl diethyl silicate and the like.

  Specific examples of the organosilane (n = 1 or 2) represented by the above formula (2) include, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltri Methoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, cyclohexyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane , Γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, Examples include diphenyldiethoxysilane, methylphenyldimethoxysilane, dimethyldipropoxysilane, and the like, and methyltrimethoxysilane, methyltriethoxysilane, and dimethyldimethoxysilane are preferable.

These organosilanes can be used singly or in combination of two or more. These may be partially hydrolyzed condensates. The polystyrene-reduced mass average molecular weight of the condensate is, for example, 300 to 5000, preferably 500 to 3000. By using a condensate having such a molecular weight, the storage stability is not deteriorated. A coating film with good adhesion can be obtained. Further, these partial hydrolysis-condensation products are suitable to have one or more, preferably 3 to 30, —OH groups or —OR ⁴ groups bonded to silicon atoms.

  Specific examples of such condensates are commercially available products such as Colcoat ethyl silicate 40, Mitsubishi Chemical MS56, Toray Dow Corning SH6018, SR2402, DC3037, DC3074; Shin-Etsu Chemical Co., Ltd. KR-211, manufactured by KR-212, KR-213, KR-214, KR-216, KR-218; TSR-145, TSR-160, TSR-165, YR-3187 manufactured by Toshiba Silicone Can be mentioned.

  The organic-inorganic composite resin as the binder may be one obtained by subjecting organosilane and / or a partial hydrolysis-condensation product thereof to a hydrolysis-condensation reaction of, for example, a silyl group-containing vinyl resin.

  For example, as the silyl group-containing vinyl resin, at least one silyl group having a hydrolyzable silyl group or a silicon atom bonded to a hydroxyl group at the terminal or side chain of the vinyl resin, preferably, And having an acid value of 30 to 150 mgKOH / g, preferably 35 to 80 mgKOH / g, preferably having a mass average molecular weight of about 10,000 to 50,000, more preferably a mass average molecular weight of 13,000. A 35000 vinyl resin is preferred.

  The silyl group is preferably one represented by the following formula.

-SiX _P (R ⁵ ) _(3-P) (3)
In formula (3), X is an alkoxy group, a hydrolyzable group such as an acyloxy group, a halogen atom, a ketoximate group, a mercapto group, an alkenyloxy group, or a phenoxy group, or a hydroxyl group, and R ⁵ is a hydrogen atom or a carbon atom. It is a monovalent hydrocarbon group such as an alkyl group, an aryl group, or an aralkyl group having 1 to 10, and P is an integer of 1 to 3.

  The alkyl group in the alkoxy group is, for example, suitably an alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and may be linear or branched. Specific examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, and a t-butyl group. Preferred examples include groups and pentyl groups.

  Preferred examples of the acyloxy group include an acetoxy group and a benzoyloxy group. As a halogen atom, a chlorine atom, a bromine atom, a fluorine atom, etc. can be mentioned suitably, for example. Preferred examples of the ketoximate group include an acetoxymate group and a dimethyl ketoximate group. Preferable examples of the alkenyl group in the alkenyloxy group include alkenyl groups corresponding to the above alkyl groups.

The alkyl group having 1 to 10 carbon atoms as R ⁵ may be linear or branched. Specific examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, and a t-butyl group. Preferred examples include groups and pentyl groups.

  Preferable examples of the aryl group include a phenyl group.

  The aralkyl group is a group having a structure in which a hydrogen atom of an alkyl group is substituted with an aryl group, and the ranges of the alkyl group and the aryl group are as described above.

The silyl group-containing vinyl resin is, for example, the following formula:
(X) _P (R ⁵ ) _(3-P) Si—H (4)
[In the formula (4), X, R ⁵ and P have the same meaning as in the above formula (3). ]
It can manufacture by making the hydrosilane compound shown by and the vinyl-type resin which has a carbon-carbon double bond react according to a conventional method.

  Typical examples of such hydrosilane compounds include methyldichlorohydrosilane, methyldiethoxyhydrosilane, methyldiacetoxyhydrosilane, and the like. The amount of the hydrosilane compound used is suitably 0.5 to 2 moles relative to 1 mole of carbon-carbon double bonds contained in the vinyl resin.

  The vinyl resin contains (meth) acrylic acid, carboxylic acids such as itaconic acid and fumaric acid or acid anhydrides such as maleic anhydride as essential vinyl monomers, and methyl (meth) acrylate. And (meth) acrylic acid esters such as ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylic acid; acrylonitrile, styrene, α-methylstyrene, acetic acid Vinyl monomers selected from the group consisting of vinyl, vinyl propionate and the like; 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- ( Polymerizable light stabilizers such as (meth) acryloylamino-2,2,6,6-tetramethylpiperidine; 2-hydride Preferred examples include a copolymer of a polymerizable ultraviolet absorber such as xyl-4-((meth) acryloyloxyethoxy) benzophenone. At the time of producing the copolymer, aryl (meth) acrylate, diaryl phthalate, etc. By carrying out radical copolymerization, it becomes possible to introduce a carbon-carbon double bond for hydrosilylation reaction in the vinyl resin.

  In the above carboxylic acid or acid anhydride, the acid value of the vinyl resin obtained is preferably 30 to 150 mgKOH / g, more preferably 35 to 80 mgKOH / g in the constituent monomer of the copolymer. To contain. When the acid value is smaller than the above range, the storage stability of the resulting aqueous dispersion is deteriorated. On the other hand, when the acid value is large, the water resistance and hot water resistance of the obtained coating film are deteriorated.

  Moreover, as other manufacturing methods of the silyl group-containing vinyl resin, the vinyl monomer containing the carboxylic acid or acid anhydride and 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Hydroxyl-containing monomers such as 2-hydroxyethyl vinyl ether, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, β- (meth) acryloxyethyltrimethoxysilane, β -(Meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloxypropylmethyldipropoxysilane, γ -(Meth) acryloxybutyl There is also a method of radical polymerization with a silyl group-containing vinyl compound such as enyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropyldiethylmethoxysilane. Specific examples of these silyl group-containing vinyl resins include, for example, Kanekazemulac manufactured by Kaneka Chemical Industry Co., Ltd. as a commercial product.

  The water-based paint used in the present invention preferably contains a colloidal silica in which silica particles are dispersed in water.

  Colloidal silica is usually a type in which approximately spherical silica particles having an average particle diameter of 5 to 100 nm, preferably 10 to 30 nm are dispersed, and the silica particles are chained to have a thickness of about 5 to 50 nm and a length of about 40 to 400 nm. There are a type in which the particles are aggregated and dispersed in a solution, a type in which silica particles having an average particle diameter of 5 to 50 nm are aggregated in a ring and dispersed in the solution, and the like. Also, different types can be mixed and used.

  Colloidal silica is used for improving the curability and stain resistance of the coating film, and the blending amount is suitably 0.1 to 50% by mass in terms of solid content in the paint. When the blending amount is large, the curability of the coating film and the stain resistance are improved. On the other hand, when the blending amount is too large, the mixing stability and the crack resistance of the coating film tend to decrease.

  Colloidal silica is usually mixed and used as it is in a water-based paint, but it may be used after hydrolytic condensation reaction with the inorganic resin or organic-inorganic composite resin described above.

  In that case, in order to accelerate the hydrolysis condensation reaction, it is preferable to add an acid such as acetic acid, hydrochloric acid, nitric acid, formic acid, or a basic compound such as ammonia or an amine compound as a catalyst.

  The hydrolysis or partial condensation reaction is usually carried out at 40 to 80 ° C., preferably 45 to 65 ° C., for example, for 2 to 15 hours. In the presence of a catalyst, the reaction may be carried out at room temperature. Is possible.

  By reacting colloidal silica with an inorganic resin or organic-inorganic composite resin as a binder, colloidal silica forms a network structure in the coating film, which can further improve the hardness and stain resistance of the coating film. it can. A cement-based binder using Portland cement or the like may be used as the binder. In addition, in the organic-inorganic composite resin, an acrylic resin, a urethane resin, or an epoxy resin can be used.

  The water-based paint used in the present invention includes a binder as a main component, a curing accelerator that accelerates the curing of the paint as necessary, a filler, an extender pigment, a coloring pigment, a rust preventive pigment, an ultraviolet absorber, a light It is composed of a blend of various additives such as stabilizers, antioxidants, thickeners, pigment dispersants, leveling agents, fungicides, and preservatives.

  The water-based paint is suitably applied once or several times by means of brush, roller, spray, etc. to form a coating film having a dry film thickness of 1 to 100 μm, and is dried at room temperature or by heating. It is possible to form a coating film.

(D) About multilayer coating film About the multilayer coating film formed with the polymer cement mortar for adhesion by the method of the present invention, mesh sheet, and water-based coating, the load resistance per 10 cmφ is 1.5 kN or more and displacement Is preferably 10 mm or more in terms of anti-peeling performance. In addition, it is preferable to form a multilayer film with an inorganic material so as to suppress generated gas that adversely affects the human body at the time of a fire and to suppress the spread of fire.

  Furthermore, it is preferable for use in a tunnel that the multilayer coating film has a luminous reflectance of 60% or more that indicates what percentage of light is reflected when light hits an object. In addition, the East Japan Expressway Co., Ltd. Design Guideline Vol. 3 (3) Tunnel Interior Work Edition In the April 2006 edition of the material standard for 7-2 panel interior boards, the initial standard value for luminous reflectance is 60%. That's it. The luminous reflectance means brightness that can be expressed by a Y value in the XYZ color system.

  When the multilayer coating film according to the present invention is heated for 6 minutes in a gas hazard test using a mouse, the average time from the start of the test to the stop of the action of the mouse may be 6.8 minutes or more. It is preferable from the viewpoint that no toxic gas is generated at the time of a fire, and even if it is generated, it is a trace amount.

During combustion of the multilayer coating film according to the present invention, it is a fire that the generation amount of each of the generated gases CO, HCl, HCN, NH ₃ , SO ₂ + SO ₃ and NO + NO ₂ is 0.1 mg / g or less. Even if toxic gas is sometimes generated, it is preferable from the viewpoint of a trace amount.

  The multilayer coating film according to the present invention preferably has a flame extinction time of 30 seconds or less in a fire spread test, and the tip of a fire due to combustion is less than 600 mm from the ignition point from the viewpoint of nonflammability of the coating film.

  The concrete peeling prevention method of the present invention can be applied to concrete structures such as tunnels, bridges, road viaducts, buildings, walls, chimneys, water tanks, etc. It is preferably applied to a concrete interior part that is a closed space.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. In the examples, “parts” and “%” are based on mass unless otherwise specified.

(Examples 1-3 and Comparative Examples 1-2)
Table 1 below shows the coating specifications of Examples 1 to 3 and Table 2 shows Comparative Examples 1 and 2.

<Preparation of specimen and curing method>
Materials used in Examples 1 to 3 and Comparative Examples 1 and 2 Epoxy resin polymer cement (trade name: Regigard S9000-3P, manufactured by Dainippon Paint Co., Ltd., epoxy equivalent of 180 g / eq, epoxy resin is a hydrophobic liquid type Yes, a water-soluble amine resin curing agent is used as the curing agent, and the epoxy resin in the main component is mainly composed of bisphenol A type epoxy resin.The polymer cement is 8% resin component, 34% cementitious compound, aggregate 38%, 4% admixture, 16% water))
Acrylic resin polymer cement (trade name: Regardard S7000, manufactured by Dainippon Paint Co., Ltd., polymer cement is composed of 8% resin component, 34% cement compound, 38% aggregate, 4% admixture, and 16% water. Consisting of each component),
Vinylon triaxial mesh sheet (trade name: TSS-1810-Y, manufactured by Unitika Ltd., eye size (mesh) is 10 mm per side),
Polyamide biaxial mesh sheet (trade name: KSM sheet, manufactured by Kyowa Corporation, eye size (mesh) is 3 mm per side),
Organic inorganic composite water-based primer (trade name: Regigard Primer W, Dainippon Paint Co., Ltd., synthetic resin emulsion 25.3%, pigment / aggregate 22.1%, additive 10.3%, modified polyamidoamine resin emulsion 3.9%, calcium-based binder 38.4% each component)),
Water-based inorganic paint (trade name: Regigard TN-1, manufactured by Dainippon Paint, 24.0% binder, 12.6% pigment, 4.2% additive, 59.2 water) ,
Intermediate coating for solvent-based polyurethane resin coatings (trade name: V Top H intermediate coating, manufactured by Dainippon Paint Co., Ltd.)
Solvent-based polyurethane resin paint top coat (trade name: V Top H top coat, manufactured by Dainippon Paint Co., Ltd.)
Was applied and pasted on a concrete flat plate shown below using a roller, a trowel, etc., and subjected to each test after predetermined curing.

  The substrate preparation for the preparation of the concrete specimens was carried out using a disk sander (# 20 abrasive disk), with the surface fragile layer and foreign matter removed.

<Test and evaluation method>
Each test method and evaluation method were performed as follows.

<Coating appearance>
Table 1 and Table 2 show a concrete flat plate (W / C (water / cement ratio) = 60%) with dimensions of 60 × 300 × 300 mm in a test room at a construction temperature of 23 ° C., a humidity of 50% RH, and no wind. Construction was performed according to the coating specifications. Curing was performed for 7 days in this test room and used for the test. Luminous reflectance was calculated from a reflection spectrum measured with a spectrophotometer (CR-400 manufactured by Konica Minolta Seising Co., Ltd.), and the coating film was visually observed and judged according to the following evaluation criteria.
A: The luminous reflectance is 60% or more, and the coating film is uniform.
X: Luminous reflectance is less than 60% or the coating film is not uniform.

<Peeling prevention performance>
Construction was performed according to the coating specifications shown in Tables 1 and 2 using a U-shaped lid specified in JIS A 5372: 2000 and a nominal type 300 (400 × 600 × 60 mm). The test was conducted in accordance with the May 2003 edition of the Metropolitan Expressway Co., Ltd. Maintenance Facility Department Concrete Fragment Prevention Measure Guidelines (draft). Evaluation was performed according to the following evaluation criteria.
-Load resistance ○: A punching load per φ10 cm of 1.5 kN or more.
X: The punching load per φ10 cm is less than 1.5 kN.
-Elongation performance (circle): There exists a displacement of 10 mm or more in a punching test.
X: There is no displacement of 10 mm or more in the punching test.

<Adhesiveness>
Using a mortar piece having a size of 20 × 70 × 70 mm, construction was performed according to the construction specifications shown in Tables 1 and 2. After curing, the curing was performed in a thermostatic chamber (humidity 50% RH) at 23 ° C. and 5 ° C. for 7 days and 30 days, respectively. The test was conducted using a Kenken-type adhesive strength tester and evaluated according to the following evaluation criteria.
○: 1.5 N / mm ² or more.
×: 1.5N / mm less than ^2.

<Combustion gas analysis>
According to the analysis method of JIS K 7217 plastic combustion gas, gas analysis of CO, CO ₂ , HCl, HCN, NH ₃ , SO ₂ + SO ₃ and NO + NO ₂ generated during combustion of the multilayer film was performed. Evaluation was performed according to the following evaluation criteria.
○: The generation of gases other than CO ₂ is less than 0.1 mg / g.
×: occurrence of the analyte gases other than CO ₂ is respectively 0.1 mg / g or more.

<Gas hazard>
Conducted a gas hazard test using mice based on the Building Standards Act (from the “Better Living Enactment“ Fireproof and Fireproof Performance Test / Evaluation Procedure Method ”” (Gas Hazard Test / Evaluation Method)).

  When eight mice were used in a test apparatus composed of a heating furnace, a stirring box, a test box, a rotating basket, a mouse action recording device, etc., and the multilayer coating film was heated for 6 minutes under the conditions shown in Table 3, The average time from the start of the test until the mouse stopped moving was measured. Evaluation was performed according to the following evaluation criteria.

○：８匹のマウスが行動を停止するまでの時間が平均６．８分以上。
×：８匹のマウスが行動を停止するまでの時間が平均６．８分未満。

○: The average time until the eight mice stop moving is 6.8 minutes or more on average.
X: The time until 8 mice stop moving averaged less than 6.8 minutes.

<Fire spread test>
JHS 738-2007 Tests were conducted in accordance with the flame spread test method for tunnel repair materials, and the flame extinction time of the multilayer coating film and the reach distance from the ignition point at the tip of the fire due to combustion were measured. The determination was made according to the following evaluation criteria.
○: The extinguishing time is 30 seconds or less, and the tip of the fire due to combustion is less than 600 mm from the ignition point.
X: The extinguishing time exceeds 30 seconds, or the tip of the fire due to combustion is 600 mm or more from the ignition point.

  Table 4 shows the results of these tests.

※「−」は「測定なし」を意味する。

* “-” Means “no measurement”.

From the results of Table 4, it can be confirmed that in Comparative Example 1, there is no mesh-like sheet, and the polymer cement and the water-based paint alone do not exhibit the anti-peeling performance. In Comparative Example 2, a general polyurethane resin paint intermediate coat and top coat having a high organic component content is used, and any one of HCl, HCN, NH ₃ , SO ₂ + SO ₃ and NO + NO ₂ is contained in the combustion gas. Since it is contained and uses a solvent-based paint, it can be said that it is not suitable for construction work in a closed space such as in a tunnel. On the other hand, each of Examples 1 to 3 has good performance and balance without causing these problems.

  According to the peeling prevention method according to the present invention, the concrete structure has a peeling prevention performance, is an aqueous material and the amount of organic solvent discharged into the environment is extremely small, and no organic solvent is used. The load on the human body can be reduced, and the possibility of a fire can be suppressed. Further, by using an inorganic coating as the water-based coating, non-flammability can be imparted to the coating film, and no toxic gas is generated even in the event of a fire. The present invention exhibits an excellent effect especially on the prevention of peeling of concrete pieces such as tunnel inner wall surfaces.

Claims (9)

  A concrete peeling prevention method characterized in that a concrete structure surface is coated with an adhesive polymer cement mortar and a mesh-like sheet on a concrete structure, and then covered with a water-based paint.   The concrete peeling prevention method according to claim 1, wherein the adhesive polymer cement mortar includes a hydrophobic liquid epoxy resin and a curing agent.   The concrete peeling prevention method according to claim 1 or 2, wherein the mesh sheet is a vinylon resin triaxial mesh sheet or a polyamide resin biaxial mesh sheet.   The concrete peeling prevention method according to any one of claims 1 to 3, wherein the water-based paint is at least one of a water-based inorganic paint and a water-based organic-inorganic composite paint.   The multi-layer coating film formed of the adhesive polymer cement mortar, the mesh sheet and the water-based paint has a punching load per 10 cmφ of 1.5 kN or more and a displacement of 10 mm or more in the punching test. 4. Concrete peeling prevention method according to any one of 4 above.   In the gas hazard test using a mouse, when the multilayer coating film is heated for 6 minutes, the average time from the start of the test until the mouse stops the action is 6.8 minutes or more. Concrete peeling prevention method described in any one. The generated gas at the time of combustion of the multilayer coating film, each generation amount of CO, HCl, HCN, NH ₃ , SO ₂ + SO ₃ and NO + NO ₂ is 0.1 mg / g or less. Concrete peeling prevention method described in Crab.   The concrete peeling prevention method according to any one of claims 1 to 7, wherein the multilayer coating film has a flame extinction time of 30 seconds or less in a fire spreadability test, and the tip of a fire due to combustion is less than 600 mm from the ignition point.   The concrete peeling structure according to any one of claims 1 to 8, wherein the concrete structure is a tunnel interior part.