KR101441949B1 - Method of repairing and protecting concrete structure using eco-friendly lightweight hybrid water-repellent polymer mortar composition and surface protecting material - Google Patents

Abstract

The present invention relates to a method of repairing and protecting a concrete structure. More specifically, the present invention provides an eco-friendly method of repairing and protecting a concrete structure which has an excellent durability due to having excellent water repellency and maintaining low absorption rate, having an excellent ability to repair and construct a concrete structure by reducing unit weight of mortar and improving initial and long-term attaching performance, and being eco-friendly by not using an organic solvent. Specifically, the method of repairing and protecting according to the present invention includes a water repellent mortar composition to improve water repellent effect and lower absorption rate to improve durability, thereby maintaining excellent initial and long-term durability without constructing a separate surface protection agent, being able to repair and construct without traffic regulation when constructing a bridge to which shock or vibration is applied by constituting a mortar composition using a lightweight aggregate, and lowering contractibility and expressing strength in a short time by using an expansion agent in which calcium sulfo-aluminate and plaster are mixed in an optimal ratio, and further improving long-term durability by including fiber and polyvinyl acetate (PVA) group powder resin in the mortar composition to improve long-term attaching performance and crack resistance.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for repairing and repairing a concrete structure using an eco-friendly lightweight hybrid water-repellent polymer mortar composition and a surface-

More particularly, the present invention relates to a method for repairing and repairing a concrete structure, and more particularly, to a method for repairing and repairing a concrete structure, which is excellent in water repellency and low water absorption rate and therefore has excellent durability, The present invention relates to an eco-friendly repair and protection method of an environmentally friendly concrete structure because it is excellent in maintenance workability and does not use an organic solvent.

In general, reinforced concrete structures are deteriorated due to deterioration such as neutralization, salt corrosion, chemical erosion, freezing and thawing, poor construction, etc., resulting in the deterioration of concrete structure and structural safety as well as corrosion of reinforcing steel. Therefore, as the deterioration of concrete structures continues, there is a risk of collapse of the structure. Therefore, it is necessary to continuously manage and repair the concrete structure.

That is, peeling, defects, and cracks on the surface of concrete structures facilitate the movement of deterioration factors and promote the progress of deterioration. Therefore, in order to secure the safety and performance of the reinforced concrete structure, And it is necessary to improve durability performance.

Conventionally, various techniques for repairing deteriorated concrete structures have been proposed.

For example, Korean Patent Registration No. 10-0932222 proposes a method for repairing a concrete surface using an aqueous epoxy resin mortar composition. In this technique, when the aqueous epoxy resin mortar composition is used, the work is completed by the shortened process, and the workability is greatly improved, and the mechanical properties such as strength are improved and the environment-friendly construction is possible. However, the epoxy resin mortar composition is excellent in initial adhesion and watertightness, but has a problem that long-term adhesion performance may be deteriorated due to a difference in thermal expansion coefficient from a concrete structure as a matrix.

Korean Patent No. 10-1133569 also proposes a method for repairing concrete structures using a polymer mortar composition. This technique uses a polymer mortar composition containing polybenzoxazole fiber and polyethylene oxide polymer to repair the concrete structure to prevent initial cracking and micro cracking occurring before and after curing and to improve durability, crack resistance and physical strength And it is excellent in workability and workability. However, the polymer mortar composition used here has a weak resistance against cracking due to external factors and is vulnerable to impact, vibration, fatigue load, and the like, which may deteriorate long-term durability.

Korean Patent No. 10-0720108 proposes a technique capable of various construction such as high-velocity copper, self-charging construction, and spraying construction using polyvinyl alcohol (PVA) based self-reinforcing fiber composite mortar. However, since it is required to have high fluidity in order to enable self-charging construction, there is a problem that it is not easy to control problems such as bunching of fibers and separation of materials, and there is a problem that workability can be lowered.

Also, Korean Patent No. 10-1364077 proposes a repair protection method for protecting a surface using a special surface protecting agent after preparing a mortar composition as a binder using industrial by-products and applying the mortar composition to a concrete section. In this technology, the self-defense function gradually expands over time after repair work, and it can be used for repair and reinforcement of underwater concrete structure because of the effect of shielding neutralization and chloride shielding effect. By recycling waste resources as an industrial by-product, As well as the fact that it can be increased. However, since the mortar composition disclosed herein has a poor water absorbability, there is a problem that a separate protective coating agent must be used, and since a mortar composition of a relatively high weight is used and initial adhesion performance is not ensured, There is a problem that the workability is deteriorated.

The present invention has been developed in consideration of the above-described circumstances of the prior art, and it is an object of the present invention to provide a concrete structure which is excellent in water repellency and low in absorbency in repairing and constructing a concrete structure requiring repair, By reducing the weight of the mortar by reducing the weight of the mortar, it is possible to improve the initial and long-term adhesion performance, water resistance and weatherability, and to construct the structure without any traffic control even for bridges with impact or vibration, And to provide an eco-friendly repair protection method for a concrete structure.

In order to achieve the above object,

(1) a pretreatment step of chipping, grinding, and cleaning the concrete structure requiring high maintenance;

(2) a rust-inhibiting step in which the rust-preventive agent is applied to the exposed reinforcing bar after the concrete is removed in the pretreatment step;

(3) an adhesive applying step of applying an adhesive to the surface of the concrete structure and the reinforcing bar after the rust-proofing step;

(4) On the surface of the surface on which the adhesive is applied, 40 to 50 parts by weight of lightweight aggregate, 100 to 120 parts by weight of silica, 0.5 to 2.0 parts by weight of fibers, 0.5 to 2.0 parts by weight of a shrinkage inhibitor, Lightweight hybrid water-repellent polymer mortar comprising 3 to 7 parts by weight of silica fume, 3 to 7 parts by weight of polyvinyl alcohol (PVA) powder resin, 0.1 to 1.0 part by weight of defoamer, 5 to 10 parts by weight of swelling agent and 1 to 5 parts by weight of powdery silicone water- Applying the composition; And

(5) curing the applied lightweight hybrid water repellent polymer mortar composition;

To provide an eco-friendly repair protection method for a concrete structure.

The features and advantages of the repair and maintenance method of a concrete structure using the environmentally lightweight hybrid water repellent polymer mortar composition and the surface protective agent according to the present invention will be described as follows.

1. First, by incorporating a water repellent component into the mortar composition so as to enhance the water repellency effect and lower the water absorption rate to improve the durability, the initial and long-term durability, water resistance, and weather resistance can be maintained excellent without applying a surface protective agent.

2. In order to improve the workability of the concrete structure, it is possible to construct the mortar composition by using the lightweight aggregate, so that the repair work can be performed without any traffic control even when the bridge is subjected to impact or vibration.

3. Also, by using a swelling agent in which calcium sulfoaluminate and gypsum are mixed in an optimum ratio, the shrinkability of the composition can be lowered and the strength can be expressed in a short time.

4. In addition, by including fiber and PVA powder resin in the mortar composition, the initial and long-term adhesion performance and crack resistance can be improved to further improve the durability for a long time.

Hereinafter, the present invention will be described in more detail.

As described above, the eco-friendly repair and protection method of a concrete structure according to the present invention includes the following steps. In other words,

(1) a pretreatment step of chipping, grinding, and cleaning the concrete structure requiring high maintenance;

(2) a rust-inhibiting step in which the rust-preventive agent is applied to the exposed reinforcing bar after the concrete is removed in the pretreatment step;

(3) an adhesive applying step of applying an adhesive to the surface of the concrete structure and the reinforcing bar after the rust-proofing step;

(4) On the surface of the surface on which the adhesive is applied, 40 to 50 parts by weight of lightweight aggregate, 100 to 120 parts by weight of silica, 0.5 to 2.0 parts by weight of fibers, 0.5 to 2.0 parts by weight of a shrinkage inhibitor, Lightweight hybrid water-repellent polymer mortar comprising 3 to 7 parts by weight of silica fume, 3 to 7 parts by weight of polyvinyl alcohol (PVA) powder resin, 0.1 to 1.0 part by weight of defoamer, 5 to 10 parts by weight of swelling agent and 1 to 5 parts by weight of powdery silicone water- Applying the composition; And

(5) curing the applied lightweight hybrid water repellent polymer mortar composition.

Hereinafter, each of the above steps will be described in detail.

First, when cracks are generated in concrete due to deterioration in concrete structures, the compressive strength of concrete and the tensile strength of reinforcing bars gradually decrease after a lapse of time, and the concrete exposed to the cracks is neutralized and corrosion of reinforcing bars occurs. Diagnosis and inspection of the structure should be carried out. If such a phenomenon occurs, the concrete structure must be repaired to maintain the life of the building for a long time.

The pretreatment step is a process of crushing and finishing a section of a concrete structure that requires repair as a result of the inspection by using a machine until the unreacted concrete is removed by removing the cracked concrete and the exposed reinforcing bars. In this case, the outermost surface of the refined concrete is preferably provided with a rough surface so as to facilitate the attachment of the mortar.

Specifically, the surface condition of the concrete structure to be subjected to the repair work before the repair work of the concrete structure is checked, and the depth of the neutralization is measured using the phenolphthalein solution while chipping the surface of the deteriorated concrete. Remove the advanced concrete surface.

Subsequently, the concrete is removed and the surface is ground and cleaned using high-pressure water. A process of washing with an air compressor before the high-pressure water operation can be additionally provided.

After the pretreatment, concrete is removed in the pretreatment step, and the rust inhibitor is applied to the exposed reinforcing bars. That is, if the condition of the reinforcing bars is confirmed, if the corrosion of the reinforcing bars is severe, the back side of the reinforcing bars is taken out to remove the corrosion parts (rust) by using an iron brush or a grinder to the parts with high corrosion, It is possible to add a work of cutting a reinforcing bar and reinforcing it by inserting a reinforcing material such as a new reinforcing bar, a carbon rod, and a rod. In the present invention, an amine-based rust inhibitor such as a carboxylamine is preferably used as the rust inhibitor, but not limited thereto, and general rust inhibitor that can be used as a rust inhibitor of a steel can be used without limitation.

After the rust-preventive step, an adhesive is applied to the surface of the pretreated concrete structure and the rust-inhibited reinforcing bar. The adhesive is used to increase the adhesive force between the concrete matrix and the polymer mortar composition to be newly filled, and a commonly used adhesive may be used, which is not particularly limited in the present invention.

Next, the lightweight hybrid water repellent polymer mortar composition according to the present invention is sprayed onto the surface of the concrete structure and the reinforcing bar coated with the adhesive using a mechanical spraying apparatus.

As the mechanical injection device that can be used in the present invention, it is preferable to use an integrated mortar injection device in which a mixing device, a discharge device, a generator, and a compressor are combined or mounted.

Hereinafter, each component constituting the lightweight hybrid water repellent polymer mortar composition according to the present invention will be described in detail.

The lightweight hybrid water repellent polymer mortar composition according to the present invention comprises 40 to 50 parts by weight of lightweight aggregate, 100 to 120 parts by weight of silica, 0.5 to 2.0 parts by weight of fibers, 0.5 to 2.0 parts by weight of a shrinkage inhibitor, A mortar composition comprising 3 parts by weight of silica fume, 3 to 7 parts by weight of a polyvinyl alcohol (PVA) powder resin, 0.1 to 1.0 part by weight of a defoaming agent, 5 to 10 parts by weight of an expanding agent and 1 to 5 parts by weight of a powdery silicone water- do.

In the present invention, the cement may be Portland cement, slag cement, alumina cement or quick-setting cement. Preferably, the cement is Portland cement. Specifically, in case of Portland cement, the main components are C ₃ S 51%, C ₂ S 25%, C ₃ A 9%, C ₄ AF 9%, CaSO ₄ 4%, and the specific surface area is about 3,300 cm ² / g.

In the present invention, the lightweight aggregate preferably has a mean diameter of 50 to 200 탆 and a specific gravity of 0.7 to 1.4. The porous filler-based lightweight aggregate can increase the water content due to porosity and improve the flowability, thereby making it possible to mechanize construction of the concrete structure through the water-repellent mortar composition.

In the present invention, it is preferable that the silica sand having an average particle diameter of 0.1 to 1.2 mm is used to improve the fluidity and compactness of the mortar composition.

In the present invention, since the fiber can reduce the surface crack (crack) during curing as well as the flexural strength and tensile strength, it is effective for the initial construction stability after the mortar application and is used for the purpose of increasing initial dispersibility. In the present invention, it is preferable to use a fiber having a certain degree of hydrophilicity, for example, nylon fiber, polyvinyl chloride (PVC) fiber, glass fiber, polypropylene (PP) fiber, cellulose fiber and polyethylene fiber It is preferable to use at least one selected, but not limited thereto.

In the present invention, neopentyl glycol is preferably used as the shrinkage inhibitor. The neopentyl glycol has two alcohol groups symmetrically and two methyl groups at the alpha carbon position, thus showing excellent reactivity to the esterification reaction. In the present invention, the neopentyl glycol may be used in the form of a flake consisting of 100% white crystals or a slurry composed of 90% neopentyl glycol and 10% water.

In the present invention, the silica fume is an amorphous activated silica having an average particle size of about 0.01 to 0.5 mm and is an amorphous active silica. The silica fume reacts with calcium hydroxide at a room temperature to convert it into calcium hydrate, Pozzolanic properties.

3CaOSiO ₂ + H ₂ O → CSH (cement gel) + Ca (OH) ₂

The reason for adding the silica fume to the water-repellent mortar composition in the present invention is to improve the dispersibility and water reducing effect by the ball bearing effect by the spherical particles and improve the watertightness and the strength of the shotcrete by the filling effect of the silica fume between the cement particles, The effect of improving the adhesion of the alkaline silica reaction, and the chemical resistance can be reduced.

The PVA powder resin of the present invention not only improves the flowability of the mortar composition due to the ball bearing effect of the polymer particles but also increases the viscosity of the mortar composition to prevent the separation and prevents adhesion to the concrete structure to be repaired due to its own adhesive force It enhances the bending strength and the surface hardness of the mortar while reducing the penetration of various deterioration factors and moisture due to the film formation to prevent the neutralization, the prevention of the chemical erosion and the corrosion of the reinforcing bar after repairing, while improving the performance . In the present invention, the PVA powder resin is a colorless powder obtained by hydrolyzing polyvinyl acetate resin, which is soluble in water and does not dissolve in a common organic solvent.

The antifoaming agent is a component used to remove the macropores in the mortar to improve the strength and appearance of the mortar. Generally, a volatile oil-soluble substance or a water-soluble surfactant is used. Examples thereof include kerosene, liquid paraffin, The same mineral oil defoamer; Retentive defoamers such as animal and vegetable oils, sesame oil, castor oil and their alkylene oxide adducts; Fatty acid defoaming agents such as oleic acid, stearic acid and alkylene oxide adducts thereof; Fatty acid ester defoaming agents such as glycerin monoricinolate, alkenyl succinic acid liquid, sorbitol monolaurate, sorbitol trioleate, natural wax and the like; (Poly) oxyalkylene sorbitan fatty acid esters, (poly) oxyalkylene alkyl (aryl) ethers, polyoxyalkylene polyoxyalkylene ethers, polyoxyalkylene ethers, acetylene ethers, Oxyalkylene antifoaming agents such as sulfuric acid ester salts, (poly) oxyalkylene alkyl phosphoric acid esters, (poly) oxyalkylene alkylamines and (poly) oxyalkylene amides; Alcohol-based antifoaming agents such as octyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols and the like; Amide-based antifoaming agents such as acrylate polyamines and the like; Phosphoric acid ester antifoaming agents such as tributyl phosphate, sodium octyl phosphate and the like; Metal soap defoamers such as aluminum stearate, calcium oleate and the like; Silicone antifoaming agents such as dimethyl silicone oil, silicone paste, silicone emulsion, organic modified polysiloxane (polyorganosiloxane such as dimethyl polysiloxane), fluorosilicone oil and the like can be used.

In the present invention, the swelling agent may be a mixture of calcium sulfoaluminate (CSA) and gypsum in a weight ratio of 4 to 9: 1 to 6, and the gypsum may be selected from anhydrous gypsum phosphate or anhydrous gypsum have.

In addition, in the present invention, the powdery silicone water repellent agent plays a role in improving the water repellency and decreasing the water absorption of the mortar composition, thereby improving the workability and workability, and specifically, n-octyltriethoxysilane (n -octyltriethoxysilane) is preferably used.

If necessary, the water-repellent mortar composition obtained by the above composition may further contain at least one additive selected from 0.1 to 1.0 parts by weight of a dispersant, 0.01 to 1.0 parts by weight of a retarder, and 0.1 to 1.0 part by weight of an alkali activator, have.

The dispersant adsorbs on the surface of the particles of the mortar to impart charge to the particle surface, causing mutual reaction between the particles, so that the aggregated particles are dispersed to increase the flow, thereby making it possible to increase the strength due to the water reducing effect. As the dispersing agent, a conventional water reducing agent can be used, and it can be used singly or in a mixture of two or more thereof, for example, from the group consisting of lignin sulfonate, polynaphthalene sulfonate, polymelamine sulfonate or polycarboxylate type water reducing agent. The content of the dispersant is preferably 0.1 to 1.0 part by weight based on 100 parts by weight of the cement.

The retarder may be added for the purpose of ensuring workability for a certain period of time by adjusting the hydration rate of the mortar. Examples of the delaying agent include boric acid salts such as boric acid and borax, boric acid salts such as sodium borate and potassium borate, gluconic acid, citric acid, tartaric acid, glucoheptonic acid, arabic acid, malic acid or citric acid and sodium, potassium, calcium, magnesium, An oxycarboxylic acid such as an inorganic salt or an organic salt; There may be mentioned monosaccharides such as glucose, fructose, galactose, saccharose, xylose, avitose, lipoose and isomerized sugar, oligosaccharides such as 2 sugars and 3 sugars, oligosaccharides such as dextrin, polysaccharides such as dextran, Saccharides such as molasses and the like containing them; Sugar alcohols such as sorbitol; Magnesium styrenesulfonate; Phosphoric acid and its salts or boric acid esters; Aminocarboxylic acids and their salts; Alkali-soluble proteins; Fumic acid; Tannic acid; phenol; Polyhydric alcohols such as glycerin; Aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediamine tetra (methylenephosphonic acid), diethylenetriamine penta (methylenephosphonic acid) and their alkali metal salts, And phosphonic acid and derivatives thereof such as earth metal salts. The content thereof is preferably 0.01 to 1.0 part by weight based on 100 parts by weight of the cement.

The alkali activating agent may be one or two or more selected from the group consisting of alkali metal hydroxides, chlorides, sulfur oxides and carbonates, preferably sodium carbonate and sodium hydrogencarbonate Which is advantageous in terms of strength development. In the present invention, the content of the alkali activator is preferably 0.1 to 1.0 part by weight based on 100 parts by weight of the cement.

In addition, the mortar composition according to the present invention may further include a water-reducing agent in the range of 0.1 to 3 parts by weight for maintenance and reinforcement of the underwater concrete structure. The underwater bleaching agent is added to prevent the degradation of the mortar composition by improving the viscosity of the mortar composition. Examples thereof include methylcellulose such as methylcellulose, hydroxymethylcellulose and carboxymethylcellulose; Ethyl celluloses such as ethyl cellulose, hydroxyethyl cellulose and carboxyethyl cellulose; Cellulose type thickeners selected from propyl cellulose such as hydroxypropyl cellulose can be used. The content thereof is preferably 0.1 to 3 parts by weight based on 100 parts by weight of the cement, because it exhibits an appropriate viscosity. If necessary, a water-soluble acrylic resin powder may be further added to further increase the viscosity in water, and the water-soluble acrylic resin powder is preferably used in an amount of 1 to 30% by weight of the water-decomposable agent.

The mortar composition obtained as described above is applied to the surface of the work to repair the concrete structure. When the work is repeated one or more times, the surface is polished to be adhered to the target surface to be roughly finished, and the application is performed using spray or trowel It is preferable to install and plaster 5-15 mm for primary casting, 20-50 mm for secondary and tertiary casting and 5-15 mm for final casting, but the thickness can be changed according to the thickness of the chipped concrete .

Thus, the lightweight hybrid water repellent polymer mortar composition poured on the surface of the concrete structure is cured to complete the repair work.

Meanwhile, in the repairing and repairing method according to the present invention, sufficient curability of the mortar composition can provide sufficient durability, water resistance, and adhesion strength. However, in order to improve the surface protection performance, . ≪ / RTI >

In the present invention, the surface-protecting agent may be an acrylic-urethane copolymer surface-protecting agent, but is not limited thereto. In the present invention, it is preferable that the surface protective agent is applied after about one week has elapsed since the application of the mortar composition.

In the present invention, the surface-protecting agent disclosed in Korean Patent No. 10-1364077 can be used as it is as an example of the acryl-urethane copolymerization system surface protecting agent. The surface protective agent disclosed in the patent is excellent in weathering resistance, surface strength, Do. In the present invention, it is preferable that the surface protective agent is applied at 20 to 200 g / m ² and the coating thickness is applied at a thickness of 50 to 300 μm before the drying.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by the following examples.

[Example]

(Production Example 1) Preparation of lightweight hybrid water repellent polymer mortar composition

100 parts by weight of Portland cement, 45 parts by weight of porous fillite having an average diameter of about 100 占 퐉 and a grain specific gravity of 0.9, 110 parts by weight of silica sand having an average particle size of 0.1 to 1.2 mm, 1.0 part by weight of polypropylene fiber, , 5.0 parts by weight of silica fume, 5.0 parts by weight of polyvinyl alcohol powder resin, 0.3 parts by weight of a defoaming agent, 8 parts by weight of an expanding agent mixed with a mixture of calcium sulfosilicate (CSA) and gypsum in a ratio of 6: 4, And 2.5 parts by weight of n-octyltriethoxysilane powdered silicone waterproofing agent were uniformly mixed with an appropriate amount of water to prepare a lightweight hybrid water repellent polymer mortar composition.

(Production Example 2) Preparation of lightweight hybrid water repellent polymer mortar composition

100 parts by weight of Portland cement, 45 parts by weight of a porous fillite having an average diameter of about 100 占 퐉 and a decay specific gravity of 1.1, 115 parts by weight of silica sand composed of cement with an average particle diameter of 0.1 to 1.2 mm, 1.1 parts by weight of polypropylene fiber, 7 parts by weight of an expander mixed with a mixture of calcium sulfosaluminate (CSA) and gypsum in a ratio of 6: 4, 1.2 parts by weight of a glycol shrinkage inhibitor, 5.0 parts by weight of silica fume, 7.0 parts by weight of a polyvinyl alcohol powder resin, 0.5 part by weight of an water-insoluble separating agent (methyl cellulose) and 3.0 parts by weight of n-octyltriethoxysilane powdery silicone waterproofing agent were uniformly mixed with an appropriate amount of water to prepare a lightweight hybrid water repellent polymer mortar composition.

(Comparative Production Example 1) Mortar composition production

55 parts by weight of silica sand having an average particle size of 0.1 to 1.0 mm and 100 parts by weight of the portland cement binder were mixed with 9.5 parts by weight of limestone (Kyonggi Mining Co., Ltd.) and an appropriate amount of water to prepare a mortar composition.

(Comparative Production Example 2) Mortar composition production

20 parts by weight of a synthetic slag fine powder having an average particle size of 2 to 10 탆 obtained by mixing 100 parts by weight of Portland cement, a blast furnace quenched slag and slowly cooled slowly slag at a weight ratio of 5: 5, and a mixture of calcium sulfoluminate and phosphoric anhydride gypsum at a ratio of 6: 5 parts by weight of a swelling agent mixed in a weight ratio of 1: 1, 1.0 part by weight of a polymer resin (EVA resin), 1.0 part by weight of a cellulose fiber and 0.5 part by weight of sodium hydrogencarbonate were mixed, , 9.5 parts by weight of limestone (gyeonggi mining) and an appropriate amount of water were mixed to prepare a mortar composition.

(Comparative Production Example 3) Mortar composition production

20 parts by weight of a synthetic slag fine powder having an average particle size of 2 to 10 탆 obtained by mixing 65 parts by weight of portland cement, blast furnace slag and slowly cooled slowly slag at a weight ratio of 5: 5, 20 parts by weight of calcium sulfoluminate and phosphoric anhydride gypsum at a ratio of 7: , 1.0 part by weight of a polymer resin (EVA resin), 1.0 part by weight of cellulose fiber and 0.5 part by weight of sodium hydrogencarbonate, 0.5 part by weight of an under water separator (methyl cellulose), 0.5 part by weight of a dispersant (PC) 0.5 part by weight of a defoaming agent, 0.2 part by weight of a defoaming agent and 0.05 part by weight of a retarder (tartaric acid) were added and mixed. Then, 55 parts by weight of silica sand having an average particle size of 0.1 to 1.0 mm, 9.5 parts by weight of limestone A proper amount of water was mixed to prepare a mortar composition.

(Production Example 3) Production of surface protective agent

An acrylic-urethane copolymer surface protection agent was prepared and used by the method disclosed in Korean Patent No. 10-1364077. Specifically, 682 g of neopentyl glycol and 493 g of isophthalic acid were placed in a 5-liter flask equipped with a nitrogen gas introducing tube, a stirrer, a thermometer, a cooling condenser and a bead decanter and a dropping funnel. ≪ / RTI > At this time, when the condensation water was generated while the esterification reaction proceeded, the condensed water was removed through the condenser line for 2 hours. After the condensed water was removed, the reaction mixture was re-introduced over 2 hours, and the mixture was gradually stirred and heated to react at 215 ° C. The solid acid value was measured by sampling every hour during the reaction, and when the solid acid value reached 2 mm KOH / g, the reaction was stopped and cooled to 100 ° C. At 100 DEG C, 114 g of propylene glycol and 544 g of fumaric acid were added in this order, and the temperature was raised to 165 DEG C over 2 hours in a nitrogen atmosphere. At this time, when the condensation water was generated as the esterification reaction proceeded, the condensed water was removed through the condenser line while maintaining the condensation water for 1 hour. After the condensation water was generated, the reaction mixture was reheated over a period of 3 hours, the temperature was raised to 215 캜, and the reaction was carried out. In the course of the reaction, the degree of reaction was determined by measuring 60% IN SM every hour. Gardner bubble viscosity N and an acid value of 11 mm KOH / g to obtain an intermediate. After removing the bead decanter from the flask, 79 g of 1,3-diaminopropane was added thereto after the addition of a dropping funnel, and the mixture was stabilized at 90 ° C to prepare an amine-modified unsaturated polyester resin. Thereafter, 59 g of dipentaerythritol hexaacrylate and 462 g of trimethylolpropane triacrylate prepared in advance were added to the dropping funnel, and the mixture was added dropwise for 2 hours with careful polymerization for ca. 6 poise, nonvolatile content 85%, acid value 9 67.7 g of a modified unsaturated polyester resin of mm KOH / g were synthesized. 67.7 g of the modified unsaturated polyester resin synthesized above, 2.5 g of fumed silica and 16.9 g of pigment (titanium oxide, TMC-A100, Dongwoo TMC) were mixed and thoroughly pulverized using a roller. Subsequently, 0.6 g of a defoaming agent (Airex 945, Airex 945), 0.3 g of a thixotropic agent, 14.3 g of trimethylolpropane triacrylate, and 11.9 g of methyl methacrylate were added to obtain a main component. Then, 10.15 g of a mixture of three kinds of sericite, scoria and loess (mixing ratio 40:40:20) was mixed and stirred to prepare a surface protecting agent.

[Example 1]

The surface of the damaged concrete structure was chipped, crushed and ground, and the surface was cleaned using a high pressure washer. Thereafter, an amine-based rust inhibitor was applied to the exposed reinforcing bars and an adhesive was applied to the surfaces of the concrete structures and the reinforcing bars. Thereafter, the lightweight hybrid water repellent polymer mortar composition prepared in Preparation Example 1 was applied to the surface of the structure smoothly, and then dried and cured for 4 days to finish the repair work.

[Example 2]

The surface of the damaged concrete structure was chipped, crushed and ground, and the surface was cleaned using a high pressure washer. Thereafter, an amine-based rust inhibitor was applied to the exposed reinforcing bars and an adhesive was applied to the surfaces of the concrete structures and the reinforcing bars. Thereafter, the lightweight hybrid water repellent polymer mortar composition prepared in Preparation Example 2 was applied to the surface of the structure smoothly, and then dried and cured for 4 days to finish the repair work.

[Example 3]

The surface of the damaged concrete structure was chipped, crushed and ground, and the surface was cleaned using a high pressure washer. Thereafter, an amine-based rust inhibitor was applied to the exposed reinforcing bars and an adhesive was applied to the surfaces of the concrete structures and the reinforcing bars. Thereafter, the lightweight hybrid water repellent polymer mortar composition prepared in Preparation Example 1 was applied to the surface of the structure smoothly and then dried and cured for 4 days. The surface protective agent prepared in Preparation Example 3 was coated on the dried and cured mortar surface twice with a thickness of 100 탆, followed by curing and drying to finish the repair work.

[Example 4]

The surface of the damaged concrete structure was chipped, crushed and ground, and the surface was cleaned using a high pressure washer. Thereafter, an amine-based rust inhibitor was applied to the exposed reinforcing bars and an adhesive was applied to the surfaces of the concrete structures and the reinforcing bars. Thereafter, the lightweight hybrid water repellent polymer mortar composition prepared in Preparation Example 2 was applied to the surface of the structure smoothly and then dried and cured for 4 days. The surface protective agent prepared in Preparation Example 3 was coated on the dried and cured mortar surface twice with a thickness of 100 탆, followed by curing and drying to finish the repair work.

[Comparative Example 1]

The same procedure as in Example 1 was carried out except that the mortar composition prepared in Comparative Preparation Example 1 was used for maintenance.

[Comparative Example 2]

The same procedure as in Example 1 was carried out except that the mortar composition prepared in Comparative Preparation Example 2 was used for maintenance work.

[Comparative Example 3]

The same procedure as in Example 1 was carried out except that the mortar composition prepared in Comparative Preparation Example 3 was used for maintenance work.

[Comparative Example 4]

Except that the mortar composition prepared in Comparative Preparation Example 1 and a commercially available epoxy resin coating agent (Sikafloor Co., Ltd., 1004K) were used in the same manner as in Example 1 except that the repair work was performed.

[Comparative Example 5]

Except that the mortar composition prepared in Comparative Preparation Example 2 and a commercially available epoxy resin coating agent (Sikafloor Co., Ltd., 1004K) were used in the same manner as in Example 1 except that the repair work was performed.

[Comparative Example 6]

Except that the mortar composition prepared in Comparative Preparation Example 3 and a commercially available epoxy resin coating agent (Sikafloor Co., Ltd., 1004K) were used in the same manner as in Example 1,

Performance evaluation

(1) Properties of Mortar Composition

The test samples were prepared using the mortars prepared in the above Preparation Examples and Comparative Preparation Examples, and the properties were measured by the following test methods.

1) Absorption rate, flow, slurry density: Conducted according to KS L 5220

2) Bending strength: KS F 2476 "Strength test method of polymer cement mortar"

3) Compressive strength: KSF 2405

4) Bond strength: KS F 4716 "Strength test method of polymer cement mortar"

5) Length change ratio: KS F 2424 The length change rate of mortar and concrete was measured according to the test method. The value of "0" represents the value of the initial applied body, "-" represents the shrinkage ratio, and "+" represents the expansion ratio.

The results are shown in Table 1 below.

Item Production Example 1 Production Example 2 Comparative Preparation Example 1 Comparative Production Example 2 Comparative Production Example 3 Absorption Rate (%) 17 16 25 28 31 Flow (mm) 135 140 130 119 120 Slurry density 1.58 1.48 1.80 1.96 2.01 Flexural strength
(N / mm ² ) 7 days 6.5 6.8 7.0 6.7 6.5 28th 8.1 8.9 8.5 8.9 8.5 Compressive strength
(N / mm ² ) 1 day 11.5 13.0 10.5 11.0 12.0 3 days 23.5 25.1 10.5 11.2 12.0 7 days 33.6 35.1 34.0 35.1 35.1 28th 41.5 43.0 41.0 40.1 42.0 Bond strength
(N / mm ² ) Standard condition 2.1 2.3 1.2 1.3 1.4 After warm-cold repeat 2.2 2.5 1.4 1.3 1.5 Change in length
rate(%) 3 days 0.013 0.015 0.045 0.046 0.039 7 days 0.004 0.005 0.006 0.005 0.004 14 days -0.02 -0.02 -0.05 -0.05 -0.04 28th -0.025 -0.024 -0.06 -0.055 -0.04

As shown in Table 1, the lightweight hybrid water repellent polymer mortar composition according to the present invention has remarkably excellent physical properties as compared with the conventional mortar composition.

(2) Evaluation of sectional restoration performance

1) Weatherability evaluation

ASTM G 155 for 400 hours.

2) Evaluation of surface hardness

The pencil hardness was measured according to KS D 6711.

3) Water resistance evaluation

The time at which surface deformation (cracks, blisters, etc.) occurred continuously in 90 ° C hot water was measured.

The evaluation results are shown in Table 2.

Weatherability (white) Surface hardness Water resistance Example 1 E1.3 5H 450hr Example 2 E1.2 5H 500 hr Example 3 E1.5 4H 490hr Example 4 E1.2 5H 500 hr Comparative Example 1 E3.2 3H 350hr Comparative Example 2 E3.5 4H 340hr Comparative Example 3 E3.3 3H 330hr Comparative Example 4 E3.2 3H 310hr Comparative Example 5 E3.3 4H 320hr Comparative Example 6 E3.5 3H 300hr

As shown in Table 2, when the concrete structure was repaired using the lightweight hybrid water repellent polymer mortar composition according to the present invention and the surface protection agent according to the present invention was selectively applied to the surface thereof, the conventional mortar composition was used, , The surface hardness and the water resistance are remarkably superior to those in the case of using the polyurethane resin.

From the results of the above Tables 1 and 2, it can be seen that the use of the repair protection method of the concrete structure according to the present invention is excellent in the performance of mortar, excellent adhesion with concrete, and excellent properties such as weather resistance and water resistance, Can be maintained for a long period of time.

In addition, when lightweight hybrid water repellent polymer mortar composition according to the present invention is used to repair and construct a concrete structure, lightweight aggregate is used. Therefore, even when a bridge is subjected to impact or vibration, This is possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents. Of course, such modifications should be construed as being within the scope of the appended claims.

Claims (10)

(1) a pretreatment step of chipping, grinding, and cleaning the concrete structure requiring high maintenance;
(2) a rust-inhibiting step in which the rust-preventive agent is applied to the exposed reinforcing bar after the concrete is removed in the pretreatment step;
(3) an adhesive applying step of applying an adhesive to the surface of the concrete structure and the reinforcing bar after the rust-proofing step;
(4) On the surface of the surface on which the adhesive is applied, 40 to 50 parts by weight of lightweight aggregate, 100 to 120 parts by weight of silica, 0.5 to 2.0 parts by weight of fibers, 0.5 to 2.0 parts by weight of a shrinkage inhibitor, A lightweight hybrid polymeric mortar composition comprising 3 to 7 parts by weight of silica fume, 3 to 7 parts by weight of polyvinyl alcohol (PVA) powder resin, 0.1 to 1.0 part by weight of defoamer, 5 to 10 parts by weight of swelling agent and 1 to 5 parts by weight of powdery silicone water repellent ; And
(5) curing the lightweight hybrid polymer mortar composition;
A method of eco - friendly repair and maintenance of a concrete structure.
The method according to claim 1, wherein the lightweight aggregate has a mean diameter of 50 to 200 탆 and a specific gravity of 0.7 to 1.4 in the step (4).
The method according to claim 1, wherein, in the step (4), the fiber is one or more selected from nylon fiber, polyvinyl chloride (PVC) fiber, glass fiber, polypropylene (PP) fiber, cellulose fiber and polyethylene fiber The eco-friendly maintenance method of concrete structure which is characterized by.
The method according to claim 1, wherein the shrinkage preventing agent is neopentyl glycol in the step (4).
The method according to claim 1, wherein in the step (4), the expanding agent is a mixture of calcium sulfoaluminate (CSA) and gypsum in a ratio of 4-9: 1-6. .
The method of claim 1, wherein the powdered silicone water-repellent agent is n-octyltriethoxysilane in the step (4).
[6] The method of claim 1, wherein the lightweight hybrid polymer mortar composition further comprises 0.1 to 3 parts by weight of a water-reducing agent in step (4).
[8] The method according to claim 7, wherein the water-insoluble separating agent is selected from methyl cellulose, hydroxymethyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxyethyl cellulose and hydroxypropyl cellulose. Eco - friendly maintenance method of.
The eco-friendly repair method of a concrete structure according to claim 1, further comprising a step of curing the lightweight hybrid polymer mortar composition in step (5) and then applying a surface protective coating to the surface.
[12] The method according to claim 9, wherein the surface protecting coating agent is an acryl-urethane copolymer surface protecting agent.