KR101699490B1 - Environmentally-friendly surface treatment construction method of concrete or steel reinforcement structure - Google Patents

Abstract

Provided is an eco-friendly surface coating composite method of a concrete or steel rebar structure comprising: a first step of removing a deteriorated portion of the concrete or steel rebar structure; a second step of removing impurities by cleaning the concrete or steel rebar structure from which the deteriorated portion has been removed by using high-pressure water; a third step of drying the concrete or steel rebar structure from which impurities have been removed in the second step; and a fourth step of performing surface coating on the surface of the dried surface of the concrete or steel rebar structure by using a surface finishing composition including 20-30 parts by weight of alumina cement, 5-20 parts by weight of active nano silicate, 7-13 parts by weight of nanopolymer, 20-30 parts by weight of silica, 5-20 parts by weight of surface-modified hydrophilic microfiber, and 0.1-5 parts by weight of an admixture. According to the composite construction method, the concrete or steel rebar structure can be effectively prevented from being deteriorated by blocking and precisely controlling deterioration factors with negative impact such as chlorine ions, carbonic acid gas, and moisture entering from the inside and forming a blocking system on the inside and outside of repair. When the eco-friendly surface coating composite method of a concrete or steel rebar structure is applied to a concrete material with fine cracks, additional deterioration can be prevented by preventing harmful materials from penetrating the concrete material through the cracks as an impregnation effect is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an environmentally-friendly surface treatment construction method of a concrete or steel reinforcement structure,

The present invention relates to an eco-friendly surface coating composite method for a concrete or reinforcing steel structure, and more particularly, to an eco-friendly surface coating composite method for a concrete or reinforcing steel structure incorporating a high-filled nano-polymer and a surface-

Concrete structures are permeable to carbon dioxide, chloride, and other harmful substances from the concrete surface, resulting in poor durability. In order to improve the durability of the concrete, it is necessary to develop a surface treatment material for enhancing durability among various economical and easy techniques which can effectively control the deterioration of the concrete structure.

In addition, attention has been focused on pollution prevention and cleanable structure finishing methods for maintaining the environmental importance of the above-mentioned structures. In order to solve such problems, recently, a coating material having a function of preventing contamination itself has been used as a concrete surface A method of constructing the structure is proposed. As such a coating material, an epoxy type, a urethane type, a vinyl ester type, a fluororesin type, an acrylic rubber type and the like are used.

However, when an epoxy-based or urethane-based coating material is used, its function does not reach a satisfactory level in order to cope with external conditions such as acid rain, polluted atmosphere, carbon dioxide gas, sulfur dioxide gas,

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an eco-friendly surface coating composite method for a concrete or a reinforced concrete structure having crackability and cracking ability.

According to an aspect of the present invention, there is provided a method of manufacturing a reinforced concrete structure, comprising: a first step of removing a deteriorated portion of a concrete or a reinforced concrete structure; A second step of washing the concrete or the reinforced concrete structure from which the deteriorated portion has been removed by using high pressure water to remove foreign matter; A third step of drying the concrete or the reinforcing bar structure from which foreign substances have been removed according to the second step; And 20 to 30 parts by weight of alumina cement, 5 to 20 parts by weight of active nanosilicate, 7 to 13 parts by weight of nanopolymer, 20 to 30 parts by weight of silica, 5 to 20 parts by weight of surface modified hydrophilic There is provided a surface coating composite method of a concrete or reinforcing steel structure comprising a fourth step of coating an environmentally friendly surface by applying a surface coating using a composition for surface finishing comprising microfibers and 0.1 to 5 parts by weight of an admixture .

According to the present invention, deterioration of concrete or reinforcing steel structure can be effectively prevented by blocking the harmful deterioration factors such as chlorine ions, carbon dioxide gas, moisture and the like introduced from the inside and precisely controlling them to form a blocking system in the inside and outside of the repair. In addition, it has an impregnation effect when applied to a concrete in which microcracks are generated, thereby preventing penetration of harmful substances through cracks, thereby preventing further deterioration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a surface finish coating structure of a concrete or reinforcing steel structure of the present invention. FIG.
2A is a view for explaining a protective effect of a surface finish coating film formed according to an environmentally friendly surface coating composite method according to an embodiment.
FIG. 2B is intended to illustrate the protective effect of a typical surface finish coating film for comparison with FIG. 2A.
Fig. 3 is a device used for water absorption test in Evaluation Example 2. Fig.

Hereinafter, an eco-friendly surface coating composite method of a concrete or reinforcing steel structure according to the present invention will be described in more detail.

A first step of removing a deteriorated portion of the concrete or the reinforcing structure;

A second step of washing the concrete or the reinforced concrete structure from which the deteriorated portion has been removed by using high pressure water to remove foreign matter;

A third step of drying the concrete or the reinforcing bar structure from which foreign substances have been removed according to the second step; And

20 to 30 parts by weight of alumina cement, 5 to 20 parts by weight of active nanosilicate, 7 to 13 parts by weight of a nanopolymer, 20 to 30 parts by weight of silica sand, 5 to 20 parts by weight of a surface-modified hydrophilic micro- And a fourth step of applying an eco-friendly surface coating step of applying a surface finishing composition using a composition for surface finishing comprising a fiber and an additive of 0.1 to 5 parts by weight.

The additive includes a thickener and a defoaming agent.

As the thickening agent, a cellulose type thickening agent, a polyacrylamide type water-soluble polymer, polyvinyl alcohol or polyvinyl acetate, for example, ethylhydroxyethyl cellulose is used. These materials are available under the trade name Bermocoll M10 (ethyl hydroxyethyl cellulose). And a blend of liquid hydrocarbons as the defoaming agent and available as Agitan P803, Agitan P804, or Agitan P823 sold by MUNZING CHEMIE GmbH under the trade name.

15 to 25 parts by weight of cement and 10 to 20 parts by weight of blast furnace slag are added to a defective area of a concrete or a reinforced concrete structure in which foreign substances are removed according to the second step, 1 to 5 parts by weight of active nanosilicate, 1 to 10 parts by weight of nanopolymer, 30 to 60 parts by weight of silica, and 5 to 30 parts by weight of calcium carbonate.

As described above, if the repair mortar is filled, it is possible to prevent the performance of the concrete or the reinforcing steel structure from deteriorating over time due to external influences such as load or acid rain.

Wherein the repair mortar further comprises at least one additive selected from hydrophilic microfibers, a water reducing agent and an antifoaming agent, wherein the additive is present in an amount of 100 parts by weight based on the total weight of the cement, the blast furnace slag, the active nano-silicate, the nanopolymer, 0.0001 to 3 parts by weight.

And forming a primer layer on the resultant product obtained in the third step.

The present invention can be applied to the case where the cracks and fine pore portions of the reinforcing steel or concrete structure of the present invention are leaked to thereby deteriorate the durability of the structure due to breakage, detachment, peeling or peeling of the concrete coating due to penetration of harmful deteriorating factors on the inner and outer surfaces It is maintenance method. It is an environmentally friendly surface coating method which can prevent the progress of deterioration by early application of new construction as well as improving the usability and functionality such as durability, beauty or waterproofing of concrete structure. In addition, by using nano-polymer-cement-surface modified microfibre-functional filler, the deterioration performance can be controlled to ensure the durability of the concrete structure, and also to provide the concrete concrete with volume stability and environmental friendliness. Also, it maximizes scalability so that it can be utilized as other maintenance method and system.

The surface coating method of the present invention is a method of repairing a deteriorated portion of a concrete structure, which essentially shields and precisely controls harmful deterioration factors such as chlorine ions, carbon dioxide gas, and moisture introduced from the inside to form a blocking system , It is possible to prevent deterioration of concrete. The present invention also provides a system capable of preventing further deterioration by preventing infiltration of harmful substances through cracks by applying impregnation effect to concrete which has already been microcracked.

Portland cement usually produces free lime during curing, which in combination with carbon dioxide in the air creates calcium carbonate, which can cause whitening or carbonization. This is the main cause of decrease of durability of concrete structure. The combination cement of the present invention is intended to supplement the problems of portland cement. In particular, it has characteristics of blast furnace slag reinforcing long-term strength of combination cement and strong resistance to sulfate, It is also equipped with the characteristics of three kinds of cement having water resistance in repair at the same time.

In the present invention, alumina cement is used. Alumina cement is a calcium hydroxide pre-cement and can prevent corrosion of reinforcing steel structures by high alkalinity.

In addition, most of the surface coating methods have not been developed to meet the deterioration factors and environment of concrete structures in Korea, and the effectiveness of the microcracks has not been proved effectively and the application limit is not available. However, by using the composite method of the present invention, it is possible to treat cracks caused by drying shrinkage and overloading of the surface protection method for concrete structures.

The hydrophilic fibers may be various fibers having random hydrophilic functions. In the present invention, the adsorption of the useful microorganisms and the enhancement of the survivability are one of the most important functions. In this invention, since the useful microorganisms can be settled and survived In order to improve the water purification effect, the hydrophilic fiber has a length of 2.5 -

And the diameter is preferably 0.014 to 0.016 mm.

The cellulose fibers are preferably used as the hydrophilic fibers. The cellulose fibers preferably exhibit a tensile strength of 480 to 500 MPa and a specific gravity of 1.3 to 1.5 in order to maintain the compressive strength of the concrete and maintain a proper specific gravity.

The surface-modified cellulose microfibers may be used in various forms. For example, standard and crimp types may be used, or various cross-sectional shapes such as triangular, square, and circular shapes may be used. For example, the length of the surface-modified cellulose microfibers may be 1 to 100 mm, preferably 6 to 40 mm, and the diameter of the cross-section of the surface-modified cellulose microfiber or 10 to 70 탆, preferably 20 to 40 탆 . The length, diameter, or thickness of the surface-modified cellulose microfibers can be adjusted to the optimum range depending on the quality, durability, compressive strength, bending strength, toughness, etc. of the desired concrete.

In a preferred example, the surface-modified cellulose microfibers can be used in a single length and single diameter to maintain a uniform shape. In this case, the term " single shape " means that fibers having different lengths or diameters are not mixed, and the surface modified cellulose microfibers having a single shape of single length and single diameter in terms of dispersibility in concrete are used .

The surface-modified cellulose fiber is surface-modified by a hydrophilic substance having a hydroxyl group or a carboxyl group on the surface of the cellulose fiber.

Cellulosic fibers themselves have affinity for water, but when used in products such as concrete or mortar, the cellulose fibers are unevenly homogeneous and need to be improved. As described above, the cellulose fiber is modified with a hydrophilic substance having a hydroxyl group or a carboxyl group on the surface thereof to impart polarity to the cellulose fiber, thereby enhancing the affinity with water and enhancing the solubility in water. The surface modified cellulosic fibers are excellent in compatibility with water when blended with a polymer composite cementitious material, minimize the aggregation of the fibers, and homogenize the surface of the coating.

The above-mentioned surface-modified cellulose fibers have a size of 50 mu m or less, a thickness of about 10 mu m, and a density of about 100 g / L.

The content of the surface-modified cellulose microfibers is 0.5 to 1.5 parts by weight, preferably 0.7 to 1.3 parts by weight, more preferably 0.9 to 1.2 parts by weight based on 100 parts by weight of cement. If the content of the surface-modified cellulose microfibers is less than the above range, it is difficult to obtain a superior effect in terms of structural effects such as cracking inhibiting ability and bonding strength between LMC particles. If the content of the surface-modified cellulose microfibers exceeds 1.5 parts by weight with respect to 100 parts by weight of the cement, the fiber reinforcement is not uniformly dispersed and the slump is reduced, and the field workability due to lowering of workability is partially deteriorated.

In the present invention, by injecting the fiber reinforcing material into the optimum range, it is possible to uniformly disperse the fiber reinforcing material in the concrete, thereby greatly improving the compressive strength, flexural strength, and flexural toughness. Particularly, the fiber reinforcement suppresses the occurrence of cracks as much as possible, prevents detachment of concrete fragments even if cracks occur, increases the ductility of concrete, and reduces the amount of latex admixture, thereby improving economic efficiency.

And forming a primer layer on the dried structure according to Step 3.

And spraying water after 2 to 3 days have elapsed.

The primer layer includes a first coating layer of zinc (Zn) -aluminum (Al) -zirconium (Zr) and a second coating layer formed by coating an organic hybrid coating solution.

Thermal spray The first coating layer can be thermal sprayed using a wire spraying method, a flame spraying method, a low temperature gas spraying method, a plasma spraying method, or the like. In the first coating layer, the zinc content is 2 to 20 wt%, the aluminum content is 78 to 97 wt%, and the zirconium content is 0.1 to 5 wt%. Preferably, the content of zinc is 7 to 17 wt%, the content of aluminum is 82 to 91 wt%, and the content of zirconium is 0.2 to 3 wt%. When the content of zinc, aluminum and zirconium in the first coating layer is in the above range, corrosion resistance and corrosion resistance are improved.

The thermally sprayed first coating layer has a layer thickness of 70 to 350 μm, the second coating layer has a thickness of 100 to 250 g / m 2, and the layer thickness after sealing is 5 to 100 μm. When the thicknesses of the first coating layer and the second coating layer are within the above ranges, the adhesion is excellent.

Wherein the second coating layer comprises an inorganic binder; Organoalkoxysilane; Water-soluble organic solvents; Fillers; Pigments and catalysts.

The inorganic binder may include at least one selected from the group consisting of colloidal silica, colloidal alumina, and colloidal zirconia.

In an embodiment, the organic-inorganic hybrid coating solution is a fluoro-olefin resin, a fluoroalkoxysilane (FAS), a polydimethylsiloxane (PDMS), a methylhydrogensilicone oil, a silicone resin, a silicon powder, Boron nitride (BN), and the like.

In an embodiment, the organic-inorganic hybrid coating solution may contain 5 to 70 wt% of an inorganic binder, 5 to 60 wt% of an organoalkoxysilane, 10 to 40 wt% of a water-soluble organic solvent, 5 to 60 wt% of a filler, % And 0 to 10% by weight of catalyst.

The inorganic binder may be 5 to 70% by weight, preferably 10 to 60% by weight based on 100% by weight of the total composition of the second coating layer (B). It is possible to prevent the decrease of the adhesive force in the above range and to reduce the unevenness of the film due to agglomeration or pinholes. The inorganic binders are applied for the purpose of imparting hardness, adhesion and abrasion resistance of the coating layer and have a particle size of 5 to 150 nm, preferably 10 to 50 nm.

The organoalkoxysilane may be represented by the following formula (1): < EMI ID =

[Chemical Formula 1]

Rm-Si (OR ') n

(Wherein R is a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms, R 'is an alkyl group or an acyl group having 1 to 5 carbon atoms, m is 1 to 2, n is a natural number of 2 to 3, m + n is 4)

In the above formula (1), R is a substituted or unsubstituted hydrocarbon group, wherein the substituent includes an amine group, an epoxy group and a halogen group. For example, R may include an alkyl group, an alkenyl group, an organic group containing an epoxy group, and an organic group containing an amine.

The organoalkoxysilane is preferably selected from the group consisting of methyltrimethoxysilane, propyltriethoxysilane, vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, gamma -aminopropyltrimethoxysilane, dimethyldimethoxysilane, phenyl Trimethoxysilane, and the like.

The organoalkoxysilane may be 5 to 60% by weight, preferably 10 to 50% by weight based on 100% by weight of the total composition of the second coating layer (B). It is possible to prevent the hardness from being reduced in the above content range and to reduce the occurrence of cracking or peeling.

In an embodiment, the filler may include one or more of silica, alumina, calcium carbonate, zirconium oxide, talc, and silicon carbide.

The filler may be a known inorganic filler such as silica, alumina, calcium carbonate, zirconium oxide, talc, silicon carbide or the like, and one or more of these may be used in combination. Pigments, metal powders, and the like may be mixed and used. The metal powder may be a noble metal powder, usually aluminum, nickel, zinc, or the like, and may have an average particle diameter of 1 to 100 mu m. The average particle diameter of the filler is preferably 5 to 45 mu m. The filler may be used in an amount of 5 to 60% by weight, preferably 10 to 50% by weight based on 100% by weight of the entire second coating layer (B) composition for realizing an environmentally friendly organic-inorganic hybrid coating.

The pigment may include one or more of titanium oxide, iron oxide, zinc oxide, cobalt oxide, chromium oxide, and pearl pigment. The pigment is an inorganic pigment, and the pigment preferably has an average particle diameter of 5 to 45 mu m. The pigment may be used in an amount of 5 to 60% by weight, preferably 10 to 50% by weight based on 100% by weight of the total composition of the second coating layer (B) for realizing an environmentally friendly organic / inorganic hybrid coating.

The catalyst may include one or more of phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, and the like. The catalyst is an organic acid or an inorganic acid, and has the effect of accelerating the progress of condensation reaction of colloidal silica and organoalkoxysilane when forming a coating layer.

The organic solvent is a water-soluble organic solvent, and one or more of methanol, ethanol, isopropanol, and butyl cellosolve may be used alone or in combination. The organic solvent may be 10 to 40% by weight, preferably 20 to 30% by weight based on 100% by weight of the second coating layer (B) composition for compatibility and dispersion stability of the composition.

The organic-inorganic hybrid coating solution may contain at least one selected from the group consisting of fluorine-based olefin resin, fluoroalkoxysilane (FAS), polydimethylsiloxane (PDMS), methylhydrogensilicone oil, silicone resin, silicon powder, zinc powder and boron nitride ), And the like may be further included. The fluorine-based olefin resin may preferably be Teflon (DuPont). When such a coating liquid is used, a coating film imparted with non-tackiness, antifouling property, weather resistance and stain resistance can be produced.

The additive may be used in an amount of 0.5 to 60% by weight, preferably 1 to 50% by weight, based on 100% by weight of the whole fluororesin of the fluororesin. It is possible to prevent the effect of non-sticking and stain resistance from being large in the above-mentioned content range, and the desired physical properties can not be obtained due to the low stickiness and hardness.

The fluoroalkoxysilane and polydimethylsiloxane (PDMS) perform gel-condensation reaction with silica sol in addition to organoalkoxysilane in the composition to solidify the coating layer. The fluorinated alkoxysilane may be 0.1 to 20% by weight, preferably 0.5 to 15% by weight based on 100% by weight of the total composition of the second coating layer (B), and the polydimethylsiloxane (PDMS) 0.5 to 30% by weight, preferably 1 to 25% by weight, based on 100% by weight of the total is used. According to the present invention, it is possible to perform a sol-gel condensation reaction with the silica sol in the above-mentioned content range, thereby to strengthen the coating layer. It is preferable that the methylhydrogen silicone oil has a viscosity (cSt, 25 ° C) in the range of 20 to 2000 and a hydrogen group (-H) content in the range of 0.5 to 5%, and the second coating layer (B) Can be 0.1 to 20% by weight, preferably 0.2 to 15% by weight. The non-adhesive effect of the coating layer is increased in the above content range and the occurrence of physical defects of the coating layer can be prevented.

A preferred example of the silicone resin is a methyl silicone resin having a molecular weight of 5,000 to 100,000 and a silanol group (Si-OH) of 0.05 to 2%. An example of the silicon powder is polymethylsilsesquioxane, and boron nitride is preferably hexagonal boron nitride.

The organic-inorganic hybrid coating solution may contain 5 to 70% by weight of an inorganic binder, 5 to 60% by weight of an organoalkoxysilane, 10 to 40% by weight of a water-soluble organic solvent, 5 to 60% by weight of a filler, 5 to 60% To 10% by weight.

The surface coating composite method of a concrete or a reinforcing structure of the present invention is characterized in that 15 to 25 parts by weight of cement are added to a defective area of a concrete or a reinforcing structure in which a foreign substance is removed in the defective area of the concrete or a reinforcing steel structure, 10 to 20 parts by weight of blast furnace slag, 1 to 5 parts by weight of active nanosilicate, 1 to 10 parts by weight of nanopolymer, 30 to 60 parts by weight of silica sand and 5 to 30 parts by weight of calcium carbonate .

Wherein the repair mortar further comprises at least one additive selected from hydrophilic microfibers, a water reducing agent and an antifoaming agent, wherein the additive is present in an amount of 100 parts by weight based on the total weight of the cement, the blast furnace slag, the active nanosilicate, the nanopolymer, 0.0001 to 3 parts by weight.

The content of the water reducing agent and defoaming agent in the additive is, for example, 0.0001 to 0.008 part by weight based on 100 parts by weight of the total amount of cement, blast furnace slag, active nanosilicate, nanopolymer, silica sand and calcium carbonate. The content of the hydrophilic microfibers in the additive is 0.0001 to 0.03 part by weight based on 100 parts by weight of the total amount of cement, blast furnace slag, active nanosilicate, nanopolymer, silica sand and calcium carbonate.

The water reducing agent is used to ensure the fluidity of the cement matrix. For example, a polycarboxylic acid-based high-performance water reducing agent or a naphthalene-based high-performance water reducing agent is used.

The repair mortar removes the deteriorated portion of the concrete or reinforcing structure, removes the portion, and fills the removed portion. It is also possible to increase the stiffness by increasing the cross section of the structure. Maintenance When the mortar is charged, the workability is excellent and little cracks are generated.

The nanopolymer, the active nanosilicate, is used the same as that used in the surface finishing composition. And the hydrophilic microfibers refer to hydrophilic microfibers not surface-modified in the surface-modified hydrophilic microfibers contained in the surface finishing composition.

The hydrophilic microfibers are, for example, cellulose fibers having a size of 5,000 mu m or less, a thickness of 50 to 1,000 mu m, and a density of about 30 g / L. Thus, the hydrophilic microfibers contained in the repair mortar are larger in size than the surface-modified hydrophilic microfibers contained in the surface finishing composition. As such, the hydrophilic microfibers are large in size to increase the structural stiffness of the concrete or reinforcing steel structure. The surface-modified hydrophilic microfibers are contained in the surface finishing composition, and microcracks due to drying shrinkage can be effectively controlled.

In the present invention, a process for coating the surface finishing composition on the primer layer will be described.

The composition is a composite powder type. Water is added to a composite powder by using a hand mixer, and the mixture is stirred and coated (sprayed) on a dried concrete structure by using a spray gun or the like to dry a surface finish coating film on the concrete structure . The amount of water can be determined on-site as required, and the premixed composite powder and water can be mixed on the surface of the structure by using a stirrer and various coating means such as brush, ruler, air spray and airless spray in addition to the spray gun have. When air spray is used, the nozzle diameter is 0.5 to 1.2 mm, the nozzle pressure is 43-57 psi, and in the case of airless spray, the injection pressure is at least 1500 psi or more.

FIG. 1 shows a case where a surface finish coating film is formed on a concrete structure formed according to an environmentally friendly surface coating composite method according to an embodiment.

Referring to FIG. 1, the concrete structure 10 has a structure in which a primer layer 12 is formed. A surface finish coating film 11 is formed on the primer layer 12. Although not shown in FIG. 1, an intermediate layer may be further formed between the concrete structure 10 and the primer layer 12 to bond the same.

The primer layer 121 is a coating film imparted with non-tackiness, antifouling property, weather resistance, and stain resistance.

FIG. 2A illustrates the protective effect of the concrete structure in which the surface finish coating layer of FIG. 1 is sequentially formed.

When the surface finish coating film 11 is formed on the concrete structure 10, when water vapor, water and / or foreign substances come in from the outside, water and foreign matters are removed from the surface of the surface finish coating film due to water treatment treatment of the surface finish coating film. As a result, as shown in FIG. 2B, water is prevented from passing through the surface finish coating film 21 and penetrating into the concrete structure to deteriorate.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but it should be understood that the present invention is not limited to the following examples.

Example  1: Preparation of composition for surface finishing

(VINNAPAS 5010N, WACKER), surface-modified cellulose micro fibers (Arbocel PWC500 (trade name), manufactured by Wacker), cement, micro silica (Sioxid LD), vinyl acetate-ethylene copolymer ), A defoamer (Agitan P803) and a thickener were mixed to prepare a surface finishing composition. Bermocoll M10 (Akzo Nobel Surface Chemistry) was used as the thickener.

As the cement, "alumina cement" was used, and the surface-modified cellulose microfibers having the following characteristics were used.

The surface-modified cellulose microfibers had a thickness of 10 mu m, a length of about 30 mu m and a density of about 100 g / L.

The mixing ratio of the vinyl acetate repeating unit to the ethylene repeating unit in the vinyl acetate ethylene copolymer was 5: 5, and the weight average molecular weight of the copolymer was about 50,000.

Example  2-5

A composition for surface coating was prepared in the same manner as in Example 1 except that the composition of each component was changed as shown in Table 1 below.

division Example 1
(Parts by weight) Example 2
(Parts by weight) Example 3
(Parts by weight) Example 4
(Parts by weight) Example 5
(Parts by weight) Alumina cement 25 20 30 20 30 Microsilica (active nanosilicate) 7 5 15 15 5 VA-EVA copolymer 9 7 13 13 7 Surface modified cellulose
Micro fiber 10 5 15 5 15 Defoamer 0.8 0.7 0.7 0.6 0.85 Thickener 0.2 0.3 0.1 0.2 0.2

Example  6

First, the deteriorated part of the concrete structure was removed. Subsequently, the resultant product was washed with high-pressure water to remove foreign matters, followed by drying.

Water was added to the surface finishing composition prepared in Example 1, stirred using a hand mixer, coated on a dried concrete structure using a spray gun, and dried to form a surface finish coating film on the concrete structure. The water content was adjusted so that the total content of the composition for surface finishing and water was 100 parts by weight. Therefore, the water contents in Examples 1 to 5 were 48 parts by weight, 62 parts by weight, 26.2 parts by weight, 46.2 parts by weight and 41.95 parts by weight, respectively.

Surface finishing After about two days from the formation of the coating film, water was sprayed onto the surface to perform surface coating of the concrete structure.

Example  7

Surface Finish The surface of the concrete structure was coated in the same manner as in Example 5, except that the process of spraying water onto the surface was omitted after about two days from the formation of the coating film.

Example  8-11

Surface coating of the concrete structure was carried out in the same manner as in Example 6, except that the surface finishing composition prepared according to Examples 2 to 4 was prepared instead of the surface finishing composition prepared according to Example 1 Respectively.

Example  12-14

Example 6 was carried out in the same manner as in Example 6, except that the concrete structure was washed with high-pressure water to remove foreign matters, and then charged with a repair mortar having the composition shown in Table 2 below. The surface of the structure was painted.

division Example 12
(Parts by weight) Example 13
(Parts by weight)
Example 14
(Weight ratio)

bookbinder

cement 20.4 18.7 20.4 Gross lag fine powder 10.2 10.2 10.2 Micro silica
(Active nanosilicate) 5 3.4 1.7 VA-EVA copolymer 9 1.7 1.7 Filler
Calcium carbonate 26.4 26.4 6.6 Silica sand 39.6 39.6 59.4 Other

cellulose
Micro fiber - - 0.03 * Water reducing agent - - 0.008 * Defoamer - - 0.008 *

* Polycarboxylic acid based high performance water reducing agent is used and Agitan P803 is used as antifoaming agent.

* Content based on 100 parts by weight of total weight of binder and filler

Comparative Example  One

The surface of the concrete structure was coated in the same manner as in Example 1, except that a composition for surface finishing was prepared using general cement instead of alumina cement in the preparation of the composition for surface finishing.

Comparative Example 2

The surface of the concrete structure was coated in the same manner as in Example 1, except that untreated cellulose fibers were used in place of the surface-modified cellulose microfibers in the preparation of the surface finishing composition. The untreated cellulose fibers were about 5000 microns in length, about 800 microns thick and about 30 grams per liter.

Comparative Example  3

The surface of the concrete structure was coated in the same manner as in Example 1, except that the VA-EVA copolymer was not used in the preparation of the surface finishing composition.

Comparative Example  4

The surface of the concrete structure was applied in the same manner as in Example 1, except that the VA-EVA copolymer and the surface-modified cellulose microfibers were not used in the preparation of the surface finishing composition.

Evaluation example  1: Durability evaluation

1) Examples 6-11 and Comparative Examples 1-4

The concrete structures subjected to the surface coating according to Example 6-11 and Comparative Example 1-4 were subjected to a salt spray test.

The concrete structure was treated with KS D 9502WHRJS (concentration of sodium chloride solution 5.0w / v%, pH range 6.5-7.2, spray pressure 0.7-1.8kgf / cm2, spray amount 1.0-2.0ml / 80cm2 / h, air saturation temperature 35 ± 2 ° C and a spray room temperature of 35 ± 2 ° C).

After the salt spray test, the durability was evaluated by examining the cracks and the formation of the oxide film in the surface finish coating layer in the concrete structure and classified as follows.

After brine spray test 20 days after the test, it maintains its overall shine and there is no big difference from the beginning because there is no crack: ◎

Some shine disappears after 20 days after the salt spray test, but it maintains overall luster and almost no cracks: ○

After 20 days after the salt spray test, some cracks are formed and white oxides are partially formed:

When the white oxide is formed as a whole after 20 days from the salt spray test and the crack is severe: X

The durability evaluation results are shown in Table 3 below.

division durability Example 6 ◎ Example 7 ○ Example 8 ○ Example 9 ○ Example 10 ○ Example 11 ○ Comparative Example 1 △ Comparative Example 2 X Comparative Example 3 X Comparative Example 4 X

Referring to Table 3, it can be seen that the concrete structures surface-painted according to Examples 5 to 11 have improved durability as compared with Comparative Examples 1 to 3.

2) Examples 12-14

The durability was evaluated according to the same evaluation method as in Example 5-11, and the results are shown in Table 3 below.

division durability Example 12 ◎ Example 13 ◎ Example 14 ◎

Evaluation example 2: Water  Absorption test

The water absorption test was carried out by the method of KS F 4926.

The water absorption test was performed using the apparatus shown in FIG. 3, and the water absorption rate change with time (7 days) was measured. The results are shown in Table 5 below.

3 shows the structures manufactured according to Examples 6-11 and 1-3.

As the time elapses, the water absorption rate is measured by measuring the increase in weight by immersing the sample in the water after the sample is immersed in the water without any additional pressure, and the water-tightness of the sample is examined. .

division Water absorption change (g) Example 6 0.75 Example 7 0.7 Example 8 0.65 Example 9 0.66 Example 10 0.55 Example 11 0.75 Comparative Example 1 3.25 Comparative Example 2 2.7 Comparative Example 3 2.5

It was found that the effect of reducing the water absorption rate was excellent in comparison with the case of Comparative Example 1-3 in the case of carrying out according to Examples 6-11 with reference to Table 5 above. From this, it was found that durability was improved when the surface finish coating film was formed according to Examples 6-11.

Evaluation example  3: Water absorption rate  evaluation

The water absorption rate test results of the concrete structures obtained according to Examples 12 to 14 and Comparative Example 1 were examined. The results were examined after 7 days and 28 days, and the results are shown in Table 6 below.

division Water absorption rate (7 days passed) Water absorption rate (28 days passed) Example 12 130.67 118.43 Example 13 126.67 106.67 Example 14 121.56 115.32 Comparative Example 1 210.00 172.38

As shown in Table 6, it was found that the water absorption rate characteristics of Examples 12 to 14 were improved as compared with Comparative Example 1. [

Evaluation example  3: Compressive strength test

Based on KSF2405 test method, it was evaluated according to the method by compression fracture of concrete specimen (7 days in age, 14 days in age, 28 days in age)

The results of the above compressive strength evaluation are shown in Table 7 below.

division Compressive strength (N / mm ² ) f7 f14 f28 Example 6 21.49 27.48
(27.87% increase) 32.38
(50.67% increase) Example 7 23.02 30.99
(34.62% increase) 32.74
(42.22% increase) Comparative Example 1 20.22 22.22 23.45 Comparative Example 2 20.12 21.15 22.30

Referring to Table 7, the compressive strengths of the concrete structures produced according to Examples 6 and 7 were increased with time as compared with Comparative Examples 1 and 2.

The compressive strengths of the concrete structures produced according to Examples 12 to 14 and Comparative Example 1 were examined and are shown in Table 8 below.

division Compressive strength (N / mm ² ) f7 f28 Example 12 23.42 30.99 Example 13 23.02 30.94 Example 14 22.35 27.48 Comparative Example 1 20.22 23.45

As shown in Table 8, it can be clearly seen that the compressive strength of the concrete structure produced according to Examples 12 to 14 is improved as compared with Comparative Example 1. [

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. It is possible. The scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims as well as the appended claims.

10, 20: concrete structure 11, 21: surface finishing coating film
12: Primer layer

Claims (8)

A first step of removing a deteriorated portion of the concrete or the reinforcing structure;
A second step of washing the concrete or the reinforced concrete structure from which the deteriorated portion has been removed by using high pressure water to remove foreign matter;
A third step of drying the concrete or the reinforcing bar structure from which foreign substances have been removed according to the second step; And
20 to 30 parts by weight of alumina cement, 5 to 20 parts by weight of active nanosilicate, 7 to 13 parts by weight of a nanopolymer, 20 to 30 parts by weight of silica sand, 5 to 20 parts by weight of a surface-modified hydrophilic micro- A surface finishing coating composition comprising a surface-finishing composition comprising a fiber and an admixture in an amount of 0.1 to 5 parts by weight to form a surface finish coating film,
Wherein the surface-modified hydrophilic microfine is a surface-modified cellulose fiber, and the surface-modified cellulose fiber is modified by a substance having a hydroxyl group or a carboxyl group on the surface of the cellulose fiber. The method according to claim 1,
Forming a primer layer on the dried structure according to the third step. ≪ RTI ID = 0.0 > 11. < / RTI > delete The method according to claim 1,
Wherein the surface-modified cellulose fiber has a thickness of 1 to 20 占 퐉, a density of 1 to 200 g / L, and a length of 50 占 퐉 or less. The method according to claim 1,
Wherein the nanopolymer is an ethylene vinyl acetate copolymer, or a method of coating a surface of a reinforced concrete structure. 3. The method of claim 2,
Wherein the primer layer includes a first coating layer of a thermal sparge of zinc (Zn) -aluminum (Al) -zirconium (Zr) and a second coating layer formed by coating an organic hybrid coating solution,
The first coating layer has a layer thickness of 70 to 350 탆, the second coating layer has a layer thickness of 5 to 100 탆 after being sealed with 100 to 250 g / m 2, the first coating layer contains 2 to 20% by weight of zinc, 78 to 97% by weight of zirconium and 0.1 to 5% by weight of zirconium. The method according to claim 1,
15 to 25 parts by weight of cement, 10 to 20 parts by weight of blast furnace slag, 1 to 5 parts by weight of active nanosilicate, 1 to 10 parts by weight of nanopolymer, 30 to 60 parts by weight of silica sand, and 5 to 30 parts by weight of calcium carbonate. 8. The method of claim 7,
Wherein the repair mortar further comprises at least one additive selected from hydrophilic microfibers, a water reducing agent and an antifoaming agent,
Wherein the content of the additive is 0.0001 to 3 parts by weight based on 100 parts by weight of the total weight of cement, blast furnace slag, active nanosilicate, nanopolymer, silica sand and calcium carbonate.

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