KR102177687B1 - Method for manufacturing high-durable polymer mortar including natural coir fiber, metacaulin, and water spray separator, and methods for surface repair and cross section recovery that can be dredged under water using the same - Google Patents

Abstract

The present invention relates to a method of manufacturing eco-friendly and high-durable polymer mortar containing natural coir fiber, Metakaolin, and an anti-washout agent and a surface repair and cross-section restoration method capable of being poured in water using the same and, more specifically, to a method of manufacturing eco-friendly and high-durable polymer mortar for mixing cement and admixture, fiber, Metakaolin, polymer, and an anti-washout binder in a preset weight part and manufacturing the fiber by including natural coir fiber and a surface repair and cross-section restoration method capable of being poured in water using the same. According to the present invention, the natural coir fiber is used to increase eco-friendliness, and the Metakaolin is used to ensure high durability and high fire resistance, thereby maximizing resistance to pollutants and working smoothly in adverse conditions with a large amount of influent water. In addition, it is possible to improve long-term durability and weather resistance by improving physical properties while maintaining the required characteristics of fast hardening, material inseparability, and high fluidity in repairing an underground concrete structure based on eco-friendly materials.

Description

Method for manufacturing high-durable polymer mortar including natural coir fiber, metakaolin, and non-separating agent in water, and method for surface repair and cross-section restoration that can be poured in water using the same {Method for manufacturing high-durable polymer mortar including natural coir fiber, metacaulin, and water spray separator, and methods for surface repair and cross section recovery that can be dredged under water using the same}

The present invention relates to a method for manufacturing an eco-friendly, highly durable polymer mortar containing natural coir fiber, metakaolin, and an insoluble in water, and a surface repair and cross-section repair method capable of pouring in water using the same, and more specifically, to a natural coir. In addition, fiber is used to increase eco-friendliness, and metakaolin is used to ensure high durability and high fire resistance to maximize resistance to contaminants, as well as to provide a construction method that can work smoothly in adverse conditions with a large amount of intrusion water. It relates to an eco-friendly high-durability polymer mortar composition for, and a surface repair and cross-section restoration method that can be poured in water using the same.

Currently, among concrete structures built in Korea, a significant number of underground structures currently require repair.

In order to maintain the strength and durability of these structures at the time of design, periodic inspection and maintenance have been required from basic repair to overall repair, restoration or reinforcement of the section in the case of environmentally/structurally damaged concrete. The importance of these matters is increasing as the awareness of earthquake durability and earthquake resistance has emerged.

Materials used for section restoration must meet the performance of the repair site, use conditions, environmental conditions and construction conditions. In particular, it can be said that the selection of materials according to the construction conditions is very important.

In the case of underground drainage structures such as sewage culverts, sewage pipes, water purification plants, etc., due to the characteristics of the structure, it is difficult to completely remove intrusion water and pollutants, and such repair and restoration are limited.

Therefore, in the present invention, a method that improves eco-friendliness by using natural coir fiber and uses metakaolin to maximize resistance to pollutants by securing high durability and high fire resistance, and to work smoothly in adverse conditions with a large amount of intrusion water. I would like to present.

On the other hand, as a related technology, Korean Patent Application No. 10-2015-0120379 (a method of repairing and reinforcing concrete structures using a surface protective material containing aramid fiber-containing polymer mortar and ceramic urethane) is a method of recovering the alkalinity of the concrete structure. The present invention relates to a technology that significantly improves the surface reinforcement and repair and reinforcement efficiency of a concrete structure because a surface treatment material that not only remarkably improves the surface reinforcement performance but also provides a rust prevention effect is used.

In addition, Korean Patent Application No. 10-2012-0007691 "section repair method of step-by-step concrete structures using eco-friendly geopolymer mortar" improves watertightness and improves the alkalinity of concrete by penetrating deeply into the interior of the concrete and filling the voids. It is possible to recover and suppress neutralization at the same time, increase the compressive strength and adhesive strength of the polymer mortar to be filled, and the surface protection material can be applied even in a wet state, and it relates to a cross-section repair method that prevents discoloration by ultraviolet rays.

In addition, Korean Patent Application No. 10-2015-0021669 "Anti-neutralization and concrete section repair reinforcement method using a high-strength polymer mortar composition mixed with silicon carbide (SiC) fibers and binding fixing pins" refers to bridges, roads, subways, A high-strength polymer mortar composition mixed with silicon carbide (SiC) fibers for the recovery, maintenance, and repair of concrete durability that occurs frequently in concrete structures such as tunnels and dams .

In addition, Republic of Korea Patent Application No. 10-2009-0070408 "polymer mortar composition and concrete structure repair method using the same" is cement 25.0 to 38% by weight, fine aggregate 12.5 to 28.5% by weight, fly ash 5.0 to 25.0% by weight, 0.3 to 1.5% by weight of a fluidizing agent, 0.3 to 1.2% by weight of a set retardant, 0.01 to 0.15% by weight of a curing accelerator, 3.0 to 5.0% by weight of an expanding agent, 0.1 to 1.0% by weight of admixture, 8.5 to 16.5% by weight of polybenzoxazole fibers, And by including 1.0 to 3.5% by weight of the polyethylene oxide polymer, the polymer mortar composition to prevent initial cracks and microcracks that occur before and after curing, and to a technology for improving durability, crack resistance and physical strength. .

However, the above technologies have a limitation in that they cannot provide a polymer mortar and a method that can work smoothly even under adverse conditions with a large amount of intrusion water.

Republic of Korea Patent Application No. 10-2015-0120379 (2015.08.26) "Repair-reinforcement method for concrete structure using polymer mortar comprising aramid fiber-containing polymer mortar and ceramic urethane-containing surface protective material fibers and surface protectant containing ceramic urethane)" Korean Patent Application No. 10-2012-0007691 (2012.01.26) "METHOD FOR REPAIRING SECTION OF PROGRESSIVE CONCRETE STRUCTURE USING ECO-FRIENDLY GEOPOLYMER MORTAR" Republic of Korea Patent Application No. 10-2015-0021669 (2015.02.12) "Repair-Reinforcement method using high strength polymer mortar composition mixed with silicon carbide (SiC) fibers and binding fixing pins of Concrete Structure and Neutralization Prevention using Polymer Mortar Composition and Bind pin)" Korean Patent Application No. 10-2009-0070408 (2009.07.31) "COMPOSITION OF POLYMER MORTAR AND REPAIR METHOD OF CONCRETE STRUCTURES USING THE SAME"

The present invention is to solve the above problems, by using natural coir fiber to increase eco-friendliness, and by using metakaolin to ensure high durability and high fire resistance to maximize resistance to contaminants, as well as a large amount of intrusion water. It is intended to provide an eco-friendly, highly durable polymer mortar composition to provide a construction method that can work smoothly even under adverse conditions, and a surface repair and section repair method that can be poured in water using the same.

In addition, the present invention is based on eco-friendly materials to improve long-term durability and weather resistance while maintaining the required characteristics of fast hardness, material inseparability and high fluidity in repairing underground concrete structures. It is to provide a durable polymer mortar composition, and a surface repair and section repair method that can be poured in water using the same.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the eco-friendly and highly durable polymer mortar composition according to an embodiment of the present invention comprises cement and a mixture, fiber, metakaolin, polymer, and a non-separable binder in water, respectively, in a preset weight part. But mixed, characterized in that the fiber is produced by including natural coir fiber.

In order to achieve the above object, a surface repair method capable of pouring in water using an eco-friendly, highly durable polymer mortar according to an embodiment of the present invention includes: a first step of performing a surface treatment process (chipping process) on a target surface; A second step of performing a high-pressure water washing (debris removal) process on the surface-treated area; A third step of applying an old and new adhesive to the washed area; And a fourth step of performing an eco-friendly and highly durable polymer mortar casting process in the area where the old and new adhesives are applied. It characterized in that it comprises a.

At this time, the environmentally friendly high-durability polymer mortar of the fourth step is characterized in that the use of a natural coir fiber.

In order to achieve the above object, the method for recovering a section that can be poured underwater using an eco-friendly, highly durable polymer mortar according to an embodiment of the present invention includes: a first step of performing surface treatment and rust removal of reinforcing bars on a target surface; A second step of performing a high-pressure water washing (debris removal) process on the surface-treated and rust-removed areas; A third step of applying a reinforcing bar rust prevention paint to the washed area (reinforcing bar rust prevention); A fourth step of applying an old and new adhesive to the area where the reinforced anti-rust paint is applied; And a fifth step of performing an eco-friendly and highly durable polymer mortar casting process in the area where the old and new adhesives are applied. It characterized in that it comprises a.

At this time, the environment-friendly high-durability polymer mortar of the fifth step is characterized in that the use of a natural coir fiber.

The eco-friendly high-durability polymer mortar composition according to an embodiment of the present invention, and the surface repair and cross-section restoration method that can be poured in water using the same, increase eco-friendliness using natural coir fiber, and high durability and high durability using metakaolin. It has the advantage of not only maximizing resistance to contaminants by securing fire resistance, but also enabling smooth operation in adverse conditions with a large amount of intrusion water.

In addition, the eco-friendly high-durability polymer mortar composition according to another embodiment of the present invention, and the surface repair and cross-section restoration method that can be poured underwater using the same, are characterized by rapid hardening properties in repairing underground concrete structures based on eco-friendly materials. There is an effect of improving long-term durability and weather resistance by improving physical properties while maintaining the required properties of material inseparability and high fluidity.

1 is a flow chart showing a surface repair method that can be poured underwater using an eco-friendly, highly durable polymer mortar according to an embodiment of the present invention.
Figure 2 is a flow chart showing a section recovery method that can be poured underwater using an eco-friendly, highly durable polymer mortar according to an embodiment of the present invention.

Hereinafter, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Let us look at the materials used for the eco-friendly and highly durable polymer mortar according to the present invention.

Eco-friendly, high-durability polymer mortar contains 1 part by weight and 2 parts by weight of "cement", "mixture", "fiber", "metakaolin", "polymer", and "water inseparable binder", respectively. It may be formed by mixing parts, third parts, fourth parts, and fifth parts by weight.

First, "cement" and "mixture" can be manufactured by appropriately using OPC (portland cement) in general, and crude steel cement and alumina cement in case early strength is required in consideration of field conditions.

That is, the cement can be used as general portland cement, coarse steel cement, alumina cement or magnesia cement when early strength is required, and slag cement when high strength is required, and these can be used alone or in combination.

The mixed material is silica sand, and it is preferable to use fine yarn having an average particle diameter of 0.1 to 1.2 mm, and this is to improve the fluidity and density of the eco-friendly highly durable polymer mortar.

As for "Fiber", it is preferable to use natural coir fibers alone or in combination.

Natural coir fibers are obtained from coconut palm bark, and are collected using a machine after collecting coconut husks excluding drupe from coconut fruit, pressing and crushing the collected coconut husks. Natural coir fiber is chemically stable due to its high lignin content and is resistant to microbial penetration.

In other words, natural coir fibers are red-brown, tough and resilient fibers collected from coconut palm tree bark, and are the only fibers classified as fruit fibers. Among natural coir fibers, thick and long fibers are used as brushes, and fibers with high quality and curls are used as threads, which can be used as mats, feet, rough fabrics for furniture, and ship ropes. The yarn is called coir yarn, and the fiber for the brush is called coconut fiber. It is a representative eco-friendly natural fiber that boasts chemical resistance and durability beyond chemical fiber to the extent that it is widely used in the vegetation mat method.

It was achieved in consideration of tensile strength, flexural strength, and rebound amount by maximizing the strengths of coir fiber, and it would be desirable to adjust it according to the site situation.

The natural coir fibers used in the present invention may be used alone, but may be mixed with other members and used. That is, it may be formed by adding a base resin and a reinforcing fiber-based base resin to which a waterproofing agent is added to the reinforcing fiber in which carbon fiber is added to the natural coir fiber.

More specifically, 70 to 120 parts by weight of the reinforcing fiber per 100 parts by weight of the base resin, and 2 to 5 parts by weight of a waterproofing agent are mixed to create a reinforcing fiber-based polyester resin to add a waterproof function, but the added reinforcing fiber is It can be produced by adding and mixing natural coir fibers and carbon fibers in a weight ratio of 2.3 to 2.5: 1.2 to 1.5. Here, a flame retardant may not be added.

Here, the base resin may be formed including 50 to 70 parts by weight of ABS resin and 10 to 20 parts by weight of PLA based on 100 parts by weight of the unsaturated polyester resin.

Since the unsaturated polyester resin used in the present invention is relatively inexpensive, has workability that can be cured at room temperature within a short time, excellent heat resistance, and corrosion resistance, and can exhibit various physical and chemical properties according to various selection of main raw materials. It is applied to various fields, for example, construction materials such as bathtubs and septic tanks, industrial materials such as tanks and pipes, transportation equipment such as ships and automobiles, electric insulation materials, gel coats, resin concrete, putty paints, etc. It is widely used as. However, as described above, the existing unsaturated polyester resin has good mechanical properties but has a limitation in manufacturing various injection molded products due to poor weather resistance, so in the present invention, PLA (PolyLactic Acid) and ABS resin, which are eco-friendly materials, are added. It is desirable to form.

On the other hand, ABS resin is composed of three components of acrylonitrile (A), butadiene (B), and styrene (S), and graft polymerization of a styrene-acrylonitrile copolymer with rubber such as SBR and NBR or butatiene. To manufacture ABS resin is excellent in impact resistance, chemical resistance, weather resistance, etc., in particular, excellent moldability such as injection molding and extrusion molding, and secondary processability such as coloring. It has good compatibility with another resin.

Here, PLA is a natural plant-based raw material made mainly of corn starch, does not contain synthetic resins (PC, ABS, etc.), and is 100% decomposed under natural conditions, and can prevent the generation of harmful substances such as dioxin and other environmental pollution. . PLA can be substituted for injection and extruded plastics, and it is an innovative eco-friendly resin with general-purpose physical properties that can be commercialized in a full range of plastics, and PLA is crystalline, natural circulation, biocompatible, and CO ₂ It has the characteristics of reduction, and PLA (PolyLactic Acid) is an eco-friendly material that can naturally decompose products as a plant-based raw material. More specifically, it is possible to provide characteristics capable of natural decomposition by a cycle process of plant-based raw materials, lactic acid, polymers, resin, products, and decomposition.

Here, if the ABS resin is less than 50 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin, the base resin surrounds the reinforcing fibers in the eco-friendly, highly durable polymer mortar of the added reinforcing fibers, and the base resin is cured after curing of the eco-friendly and highly durable polymer mortar. It reduces the impact resistance of the reinforcing fibers, and in the case of 70 parts by weight or more, there is a disadvantage of lowering the weather resistance by reducing the flexibility of the reinforcing fibers while surrounding the reinforcing fibers.

In addition, when PLA is less than 10 parts by weight based on 100 parts by weight of the unsaturated polyester resin, the binding strength between the reinforcing fiber and the unsaturated polyester resin and ABS resin decreases during the crystallization process of the unsaturated polyester resin and ABS resin, and exceeds 20 parts by weight. In this case, when the base resin is cured with the reinforcing fiber and other components including cement of the eco-friendly high-durability polymer mortar to crystallize, cracks occur surrounding the reinforcing fiber after a long period of time in the crystallized eco-friendly high-durability polymer mortar. A problem arises.

On the other hand, natural coir fibers and carbon fibers are added and mixed in a weight ratio of 2.3 to 2.5: 1.2 to 1.5 on the reinforcing fibers in which 70 to 120 parts by weight of the reinforcing fibers are mixed with respect to 100 parts by weight of the base resin. Fiber improves tensile strength, flexural strength, and rebound amount, while carbon fiber improves flexural strength, load deformation temperature, and Izod impact strength.

Here, when the natural coir fiber is less than 2.3 weight ratio, the tensile strength, heat resistance, and rupture strength are inferior, and when it exceeds 2.5 weight ratio, crystallization in the constituents of the eco-friendly, highly durable polymer mortar including cement by the base resin There is a problem that cracks occur during the time.

In addition, if the carbon fiber is less than 1.2 weight ratio, it becomes vulnerable to impact by external force, and if it exceeds 1.5 weight ratio, cracks occur during crystallization in the constituents of eco-friendly, highly durable polymer mortar including cement by base resin. There is a problem that occurs.

On the other hand, the waterproofing agent used in the present invention is an anionic acrylic emulsion obtained by copolymerizing an acrylic acid ester monomer and a styrene monomer to emulsify, providing excellent adhesion, and having flexibility and a membrane structure, thereby providing waterproof functionality.

"Metakaolin" fills the voids between cement particles and fine aggregates, so that the hardened body has a dense structure, thereby ensuring high durability.

Metakaolin converts calcium hydroxide generated by the hydration reaction of cement into calcium silicate hydrate that can secure strength and high durability, thereby increasing adhesion to aggregates, thereby enabling high strength expression. As the internal structure of the hardened body is formed densely, it can reduce water permeability or water absorption, thus maximizing resistance to neutralization and freezing and thawing, thereby creating a highly durable structure.

Metakaolin increases its initial strength due to the formation of ettringite and the activation of trilime silicate (C3S) in cement in the short term, and can improve compressive strength and durability through pozzolanic reaction with calcium hydroxide of cement in the medium to long term. .

"Polymer" is an acrylic re-emulsified resin, which is specially treated and has good chemical resistance, and has good electrical insulation and water resistance.

Here, the polymer serves to increase fluidity and improve workability in the state before curing of the eco-friendly high-durability polymer mortar composition, and increase surface adhesion, increase cohesion, and increase in flexural strength in the state after curing of the eco-friendly highly durable polymer mortar composition. It exhibits effects such as improving flexibility and increasing waterproofing power.

In another embodiment of the present invention, the eco-friendly, highly durable polymer mortar is a mixture of an EVA (Ethylene-vinyl acetate) resin and an acrylic re-emulsifying resin, and more specifically, 10 to 20% by weight of an EVA resin and an acrylic re-emulsifying resin 80 It is preferable to use those made up including to 90% by weight.

In the present invention, the acrylic-based re-emulsifying resin increases waterproofing and adhesion, and it is preferable to use a re-emulsifying resin manufactured by a special manufacturing method.

In the present invention, the acrylic re-emulsifying resin comprises from 80 to 90 parts by weight of an acrylic polymer and from 10 to 20 parts by weight of a monomer having a crosslinkable functional group, based on 100 parts by weight of the total monomer, 0.1 to 5 parts by weight of a reactive anionic emulsifier and a nonionic emulsifier; 0.01 to 1 part by weight of a polymerization initiator; And it is preferably an acrylic emulsion polymer obtained by polymerization of a pre-emulsion containing 45 to 50 parts by weight of water.

More specifically, the acrylic polymer is methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexylacrylate, and 2-hydroxy hexylacrylic. 2-hydroxy hexylacrylate, acrylonitrile, dimethylaminoethylmethacrylate, acetoacetoxy ethyl methacrylate, divinyl benzene, ethylene glycol Dimethacrylate (ethylene glycol dimethacrylate), butanediol dimethacrylate (buthanediol dimethacrylate), cyclo hexyl metharylate (cyclo hexyl metharylate, 3-chloro-2-hydroxypropyl methacrylate (3-chloro-2-hydroxy) -propyl methacrylate) can be used.

The monomer having a crosslinkable functional group may be used as an acrylic copolymer and a crosslinkable monomer, one or a mixture of two or more of acrylic acid, methacrylic acid, itaconic acid, maleic acid, which are unsaturated carboxylic acids, and more specifically, methacryloxypropyltri Methoxysilane, acrylonitrile, acetoacetoxy ethyl methacrylate, divinylbenzene, ethylene glycol dimethacrylate, buthanediol dimethacrylate, cyclohexyl meta Monomers such as acrylate (cyclo hexyl metharylate) and 3-chloro-2-hydroxypropyl methacrylate (Topolene M) may be used.

The reactive anionic emulsifier may be polyoxyethylene nonylphenyl ether ammonium sulfate, and as the nonionic emulsifier, alkyl polyethoxy acrylate, alkyl polyethoxy methacrylate, aryl poly Ethoxy acrylate (aryl polyethoxy acrylate), aryl polyethoxy methacrylate (aryl polyethoxy methacrylate) and the like can be used.

The polymerization initiator may be ammonium persulphate (APS), potassium persulfate (KPS), sodium persulfate (SPS), sulfoxycylate, t-butyl hydroperoxide, or the like.

The acrylic re-emulsifying resin is based on 100 parts by weight of a total monomer consisting of 80 to 90 parts by weight of an acrylic polymer and 10 to 20 parts by weight of a monomer having a crosslinkable functional group, 0.1 to 5 parts by weight of a reactive anionic emulsifier and a nonionic emulsifier; 0.01 to 0.21 parts by weight of a polymerization initiator; And it is preferably an acrylic emulsion polymer obtained by polymerization of a pre-emulsion containing 45 to 56 parts by weight of water.

The acrylic re-emulsifying resin is prepared in a pre-emulsion state by mixing a reactive anionic emulsifier and a nonionic emulsifier with an acrylic copolymer and a monomer having a crosslinkable functional group, and water, and the temperature is maintained at about 70 to 90° C. in the pre-emulsion. Up to about 10% by weight of the initial polymerization reaction. Subsequently, the remaining amount of the pre-emulsion and the polymerization initiator are administered to the reaction product over about 5 to 10 hours, subjected to continuous polymerization, and then aged for about 30 to 90 minutes. Thereafter, an acrylic re-emulsified resin can be prepared by cooling after passing through a post reaction at about 60°C.

In the present invention, the polymer component preferably has a solid content of 45 to 52%, a pH of 8.0 to 9.5, and a viscosity of 200 to 2000 cps.

In the present invention, the polymer is a mixture of EVA resin and a special acrylic re-emulsified resin, thereby improving workability and water resistance, bending strength, tensile strength and adhesion strength, drying shrinkage resistance, mechanical properties, chemical resistance, freeze-thaw resistance. It is possible to maximize the durability including, and at the same time secure economical efficiency.

The "inseparable binder in water" has the main components shown in Table 1 below.

That is, the "inseparable binder in water" may be formed including a thickener, a defoaming agent, a curing accelerator, and a fluidizing agent.

division main ingredient Thickener Cellulosic -Methyl Cellulose (MC)
-Ethyl Cellulose(EC)
-Hydroxyethyl Cellulose(HEC)
-Hydro Prophylen Cellulose(HPC)
-Hydro Ethyl Methyl Cellulose(HPMC)
-Hydro Bentonie Methyl Cellulose (HBMC)
-Hydrt Ethr Ethyl Cellulose (HEEC)
-Carboxy Methyl Cellulose (CMC) Acrylic -Polyacrylamide
-Soda acrylic acid
-Polyethylene oxide (PEO)
-Copolymer of polyacrylamide and soda acrylic acid Antifoam High-grade alcohols, phosphate esters, silicones, Dibuty Buthanol, Tributhyl Phosphate Gylcols, water-insoluble alcohols Hardening accelerator Alumina cement, calcium sulfo aluminate, calcium chloride, sodium silicate, calcium silicate, sodium sulfate, calcium sulfate, lithium chloride, lithium sulfate Fluidizing agent Melamine selphonic acid, naphthalene sulfonic acid, polycarboxylic acid, lignin sulfonic acid, alkylaryl sulfonic acid

That is, the "inseparable binder" is added to prevent the material from being decomposed and separated by improving the viscosity of the eco-friendly, highly durable polymer mortar composition in water, and it is preferable to use a mixture of a cellulose-based thickener and an acrylic thickener. And, specifically, it is preferable to use a mixture of 30 to 40% by weight of a cellulose thickener and 60 to 70% by weight of an acrylic thickener.

Cellulose thickeners include Methyl Cellulose(MC), Ethyl Cellulose(EC), Hydroxyethyl Cellulose(HEC), Hydro Prophylen Cellulose(HPC), Hydro Ethyl Methyl Cellulose(HPMC), Hydro Bentonie Methyl Cellulose(HBMC), Hydrt Ethr Ethyl Cellulose( HEEC), Carboxy Methyl Cellulose (CMC), and is a kind of polysaccharide polymer, and the polymerization degree and viscosity of the thickener are determined according to the polymerization degree of the pulp as a raw material, and the properties appear different depending on the molecular weight, substitution rate, and viscosity. Therefore, rather than using one type of thickener, it is preferable to select and use a thickener having an appropriate viscosity value in combination.

The acrylic thickener is composed of at least one of polyacrylamide, acrylic acid soda, polyethylene oxide (PEO), and a copolymer of polyacrylamide and acrylic acid soda, and is mainly composed of polyacrylamide, has low setting delay and low bubble generation. However, since there is a disadvantage that the workability is remarkably deteriorated with the passage of time, it is preferable to properly mix and use a cellulose-based and an acrylic-based in order to solve this disadvantage.

On the other hand, the antifoaming agent in the present invention is a component used to improve the strength and appearance of the eco-friendly highly durable polymer mortar by removing macropores in the eco-friendly highly durable polymer mortar. Surfactants are used, and examples thereof include higher alcohols, phosphate esters, silicones, and water-insoluble alcohols.

Further specific examples include mineral oil-based antifoaming agents such as kerosene and liquid paraffin; Oil and fat antifoaming agents such as animal and vegetable oil, sesame oil, castor oil and alkylene oxide adducts thereof; Fatty acid-based antifoaming agents such as oleic acid, stearic acid, and alkylene oxide adducts thereof; Fatty acid ester antifoaming agents such as glycerin monoricinolate, alkenyl succinic acid fluid, sorbitol monoraulate, sorbitol trioleate, and natural wax; Polyoxyalkylenes, (poly)oxyalkyl ethers, acetylene ethers, (poly)oxyalkylene fatty acid esters, (poly)oxyalkylene sorbitan fatty acid esters, (poly)oxyalkylenealkyl (aryl) ethers Oxyalkylene antifoaming agents such as sulfate ester salts, (poly) oxyalkylene alkyl phosphate esters, (poly) oxyalkylene alkyl amines, and (poly) oxyalkylene amides; Alcohol-based antifoaming agents such as octyl alcohol, hexadecyl alcohol, acetylene alcohol, and glycols; Amide antifoaming agents such as acrylate polyamine; Phosphate ester antifoaming agents such as tributyl phosphate and sodium octyl phosphate; Metal soap-based antifoaming agents such as aluminum stearate and calcium oleate; Silicone antifoaming agents such as dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil, and the like can be used.

In the present invention, the curing accelerator is one selected from among calcium chloride, sodium silicate, calcium silicate, sodium sulfate, calcium sulfate, lithium chloride, and lithium sulfate as to accelerate the curing of the eco-friendly and highly durable polymer mortar to develop initial strength, or Mixtures of two or more can be used.

In the present invention, the fluidizing agent adsorbs on the surface of the mortar particles and gives a charge on the surface of the particles, causing a mutual reaction between the particles, thereby dispersing the agglomerated particles to increase the flow and thereby enhancing the strength due to the water reducing effect. do.

As the fluidizing agent, for example, melamine sulfonic acid, naphthalene sulfonic acid, polycarboxylic acid, lignin sulfonic acid or alkylaryl sulfonic acid may be used, and more specifically, lignin sulfonate, polynaphthalene sulfonate, polymelamine sulfonate Alternatively, it is possible to use alone or in combination of two or more from the group consisting of a polycarboxylate-based water reducing agent.

In particular, since it affects the setting time when using a fluidizing agent, a setting time adjusting agent can be appropriately included.

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

[Example]

(Example 1)

In the present invention, 20 to 30 parts by weight of "cement", 50 to 60 parts by weight of "mixture", 2 to 5 parts by weight of fiber, 7 to 9 parts by weight of polymer, 5 to 6 parts by weight of "inseparable binder", The thickener, defoaming agent, hardening accelerator, and fluidizing agent constituting the "inseparable in water" are mixed in a weight ratio of 1.5 to 1.6: 0.2 to 0.4: 1.1 to 1.2: 2.3 to 2.5, and the cement is 40 weight of Portland cement. %, 35% by weight of crude steel cement, and 30% by weight of slag cement were mixed, and the mixed material was made of fine yarn with an average particle diameter of 0.1 to 1.2 mm, and a predetermined amount of natural coir fiber was used as the fiber. Water was mixed between 10 to 30 parts by weight to prepare an eco-friendly, highly durable polymer mortar composition.

(Example 2)

It was prepared in the same manner as in Example 1, but an eco-friendly, highly durable polymer mortar composition was prepared by mixing the PLA composite with natural coir fibers as fibers.

(Example 3)

An eco-friendly, highly durable polymer mortar composition was prepared by using the same method as in Example 1, but using fibers as reinforcing fibers.

Here, the reinforcing fiber is used in consideration of the necessary physical properties and economics for at least one or more including glass fiber, carbon fiber, aramid fiber, and ceramic fiber, but it is preferable to use including glass fiber.

More specifically, the unsaturated polyester resin is formed by impregnating reinforcing fibers with the unsaturated polyester resin, but the unsaturated polyester resin may be prepared through several steps. The unsaturated polyester resin is prepared by dispersing PCM capsule powder (Phase Change Material Microcapsul Powder) in glycol at a weight ratio of 1: 0.3 to 0.5 to prepare a PCM capsule powder dispersion, and then separately from the prepared PCM capsule powder dispersion, saturated acid and unsaturated acid are mixed. An acid mixture is prepared by mixing at an equivalent ratio of 0.1: 0.4 to 0.5. Thereafter, the PCM capsule powder dispersion and the prepared acid mixture are mixed in an equivalent ratio of 0.6 to 0.7: 0.2 to 0.3, and stirred at 150 to 170° C. for 40 to 50 minutes, thereby preparing a compound. Then, a styrene monomer may be mixed with the prepared compound in a weight ratio of 20 to 50: 30 to 40 to prepare an unsaturated polyester impregnated resin.

Here, the PCM capsule powder is a phase change material, and is formed of a material that repeatedly changes to solid, melting, heat energy absorption, liquid, condensation, heat energy release, and solid. On the other hand, the PCM capsule powder in the present invention provides characteristics for phase change material, size 5/1000mm (5㎛), ion repellency, anion resin, convection, heat dissipation/diffusion, etc., so that not only corrosion resistance but also heat resistance Can provide.

Meanwhile, when forming the unsaturated polyester resin by impregnating the reinforcing fiber, the first reinforcing panel forming part is formed by laminating once by laying carbon fiber of a diamond lattice structure and impregnating an unsaturated polyester resin of 160 to 170°C, and forming a roving cross. (roving cloth) type glass fiber is impregnated with unsaturated polyester resin at 150 to 160°C and laminated twice to form a second reinforcing panel formation, then wet coagulation and solvent removal, washing with water, and drying. It can be formed by forming a stratum.

Here, when the above-described unsaturated polyester impregnated resin is used, mechanical strength such as tensile strength and flexural strength may be improved to the unsaturated polyester resin, thereby providing a more flexible material.

(Comparative Example 1)

A mortar composition was prepared by mixing 100 parts by weight of Portland cement, 9.5 parts by weight of limestone, 55 parts by weight of silica sand (average particle diameter: 0.5 mm) and 3.5 parts by weight of an insoluble in water (methylcellulose). In addition, 0.5 parts by weight of a dispersant, 0.2 parts by weight of a defoaming agent, and 0.05 parts by weight of a retarder were added to 100 parts by weight of the Portland cement, and then 16 parts by weight of water were mixed to prepare a mortar composition.

(Comparative Example 2)

A composition was obtained with the same composition as Comparative Example 1, but a mortar composition was prepared in the same manner as in Comparative Example 1 by additionally including 3.5 parts by weight of a gypsum component based on 100 parts by weight of Portland cement.

(Comparative Example 3)

A mortar composition was prepared in the same manner as in Comparative Example 1 using a mixture of portland cement and crude steel cement as a binder.

Performance evaluation

(1) Physical properties of the mortar composition

A test specimen was prepared using the mortar composition prepared in the above Examples and Comparative Examples, and physical properties were measured by the following test method.

1) Setting time: KSF 2436

2) Flexural 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 rate: Measured according to the KS F 2424 mortar and concrete length change test method. The value is the value of the initial construction body as 0, "-" represents the shrinkage rate, and "+" represents the expansion rate.

6) Flow: It was carried out according to KS L 5220.

The results are shown in Table 2 below.

Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Setting time (minutes) Initial decision 27 28 31 35 38 61 closing 33 35 37 50 55 100 Flexural strength
(N/mm ² ) mourning 21 18 20 10 10 8 Underwater 18 14 15 8 9 7 Compressive strength
(N/mm ² ) mourning 78 77 78 44 44 40 Underwater 75 70 69 40 40 38 Adhesion strength
(N/mm ² ) mourning 7.6 7.3 7.1 3.2 3.5 2.0 Underwater 6.5 6.1 6.0 1.2 1.7 0.9 Length change rate (%) +0.005 +0.007 +0.008 +0.01 +0.02 +0.15 Flow(mm) 85 94 87 130 133 122

As shown in Table 1 above, in the case of the eco-friendly, highly durable polymer mortar composition according to the present invention, physical properties are remarkably excellent compared to the conventional mortar composition for underwater structures, and in particular, the flexural strength, compressive strength and adhesion strength in air and water It can be seen that it is not only remarkably excellent, but also provides remarkably relatively excellent performance in length change rate.

(2) Section recovery performance evaluation

1) Weatherability evaluation

It was measured for 400 hours according to ASTM G 155.

2) Surface hardness evaluation

Pencil hardness was measured according to KS D 6711.

3) Water resistance evaluation

The time at which surface deformation (crack, blister, etc.) occurs continuously in hot water at 120°C was measured.

Table 3 shows the evaluation results.

Weather resistance (white) Surface hardness Water resistance Example 1 △E1.7 4H 760hr Example 2 △E1.8 4H 710hr Example 3 △E1.5 4H 735hr Comparative Example 1 △E3.2 3H 420hr Comparative Example 2 △E3.5 3H 310hr Comparative Example 3 △E3.8 2H 350hr

From the results of Tables 1 and 2 above, when surface repair and cross-sectional restoration are performed using an eco-friendly, highly durable polymer mortar according to the present invention, the mortar has excellent performance, excellent adhesion to concrete, and excellent physical properties such as weather resistance and water resistance. Therefore, it can be confirmed that the repair and reinforcement of underground concrete structures can be efficiently performed, and the effect of repair and reinforcement can also be maintained for a long period of time.

On the other hand, when constructing the eco-friendly and highly durable polymer mortar according to the present invention having the above-described materials and contents, it can be by spray spraying, plastering, chute and continuous, and self-leveling.

1 is a flow chart showing a surface repair method capable of pouring in water using a highly durable polymer mortar according to an embodiment of the present invention. Referring to FIG. 1, a surface treatment process (chipping process) is performed (S11).

After step (S11), a high-pressure water washing (removing foreign matter) process is performed (S12).

That is, steps (S11) and (S12) are the pretreatment process for the repair surface, and by performing a chipping process on the surface as a grooving operation for reclaiming the surface of the concrete structure to be reinforced, the environmentally durable polymer mortar and the existing underground structures are Since it is a process that can be integrated, it is possible to create an optimal bonding environment by performing groove digging through precise cutting to enable high-quality construction. To this end, it is preferable to first check the construction location, perform grooving (grooving) work, then clean the surface with a patchwork, and perform the process of removing foreign substances sequentially through high-pressure water washing.

After step (S12), the old and new adhesive is applied (S13).

In one embodiment of the present invention, it is possible to apply new and old adhesives corresponding to various materials or made of Barra Emulsion 57, which has a mortar reinforcement effect and strong adhesion, to the surface-treated repair surface.

Barra Emulsion 57 used in the present invention is an aqueous emulsion composed of styrene and butadiene polymer and can be used in mortar or concrete to improve waterproofing, abrasion resistance, and bonding.In particular, it has excellent compatibility with cement systems. Corresponds to the cement mortar enhancer and adhesive.

After step (S13), the ground is adjusted and the environment-friendly high-durability polymer mortar pouring process according to the present invention is performed (S14).

After step (S14), the surface protection coating is applied (S15).

The surface protection coating agent used in the present invention is used in accordance with performance and economy in consideration of whether the underground structure is required for acid resistance, but can be applied with a brush, roller, or spray at the site.

When acid resistance is required in the present invention, the surface protection coating agent is composed of 25 to 27 parts by weight of an epoxy resin, 10 to 13 parts by weight of a polyurethane resin, 2 to 3 parts by weight of a flame retardant, and 1 to 2 parts by weight of a crosslinking agent based on 100 parts by weight of the flame retardant silicone adhesive. It may be formed by including the made-up subject and a curing agent.

In the present invention, the curing agent is preferably formed by mixing ashing at least among alicyclic amine curing agents, aliphatic amine curing agents, aromatic amine curing agents, acid anhydride curing agents, and imidazole curing agents.

The subject consisting of flame retardant silicone adhesive, epoxy resin, TPU resin, flame retardant, and crosslinking agent can have both flame retardancy and acid resistance.

Here, when the epoxy resin as a raw material is less than 25 parts by weight, the acid resistance characteristics are significantly reduced, and when it exceeds 27 parts by weight, it is difficult to make the surface protective coating liquid into a liquid state.

In addition, TPU as a raw material is a thermoplastic polyurethane (TPU), a rubbery elastic body having a urethane group (-NHCOO-), which has excellent mechanical strength and abrasion resistance, and has excellent properties in terms of insulation, bending resistance and coloring. I have it. TPU is a non-PVC-based thermoplastic resin that is harmless to the human body because there is no risk of generating harmful compounds, and it is environmentally friendly because it does not emit air or soil pollutants when incinerated.

Here, when the amount is less than 10 parts by weight of the TPU resin with respect to 100 parts by weight of the flame-retardant silicone adhesive, mechanical strength and abrasion resistance are significantly reduced, and when it is more than 13 parts by weight, the flexibility as a surface member is significantly lowered.

As the flame retardant, any one or a mixture of two or more of antimony molybdate, aluminum hydroxide, molybdenum oxide, and magnesium hydroxide is used. If the flame retardant is less than 2 parts by weight based on 100 parts by weight of the flame-retardant silicone adhesive, it is difficult to expect flame retardant performance, and if it exceeds 3 parts by weight, the content of the epoxy resin and TPU resin is relatively low, resulting in a problem that the acid resistance is deteriorated.

When the crosslinking agent is less than 1 part by weight based on 100 parts by weight of the flame-retardant silicone adhesive solution, it cannot function as a crosslinking agent, and when it is larger than 2 parts by weight, excessive crosslinking reaction occurs.

In addition, the curing agent preferably contains 10 to 15 parts by weight based on 100 parts by weight of the main material, and when the curing agent is less than 10 parts by weight, it cannot be cured enough to use the main material as a surface protective coating in the present invention, and exceeds 15 parts by weight. There is a problem in that the curing reaction occurs excessively and the viscosity of the surface protective coating is inferior.

In the present invention, the surface protective coating may further include a functional filler.

As the functional filler, a mixture of silica powder and expandable graphite may be used.

As the silica powder, one or a mixture of two or more selected from colloidal silica, fumed silica, and micronized silica may be used.

The functional filler serves to increase the reinforcing effect by further increasing the binding effect. In the present invention, the mixing ratio of the silica powder and the expandable graphite is preferably mixed in a weight ratio of 100:50 to 200.

In addition, when using the functional filler, it is possible to use the powder directly, but by treating the surface and coating it with an organosilane, it is possible to increase the durability due to increased binding effect.

That is, the silica powder alone or a mixture of expandable graphite powder may be treated by dispersing a colloidal solution in which a solvent is dispersed in an organic silane, followed by stirring for about 1 to 10 hours. Specifically, about 0.1 to 50 parts by weight of an organic silane is added to the solution based on 100 parts by weight of a silica powder alone or a mixture solution of expandable graphite powder to form an organic group on the surface of the powder particles in the solution and pass through the reactor to dehydration and condensation reaction. Through the organic group surface-treated powder is formed. In this case, the solution is that silica powder or expandable graphite powder is dispersed in a colloidal state in a solvent such as water or alcohol, and it is preferable to contact the organic silane in a colloidal solution state.

Specific examples of the organosilane include dimethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and tetraethoxysilane. At this time, treating the surface of the powder with organic silane is formed by stirring at room temperature for about 1 to 10 hours to form an inorganic substance having an organic group and passing it through a reactor. In this case, the reactor is a heating device, and the temperature is raised to 100 to 300°C to dehydrate and condensate the inorganic material having a solvent and an organic group formed thereon for 1 to 10 hours to prepare powdery inorganic particles having a surface treatment.

The silica powder and the expandable graphite powder prepared as described above have excellent binding effects because silane is formed on the surface thereof, and thus durability may be further improved.

In the present invention, the functional filler is preferably included in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the surface protection coating.

Meanwhile, in the present invention, the surface protection coating agent is used where acid resistance is not required, but can be applied with a brush, roller, or spray in the field.

In other words, when the environmentally friendly high-durability polymer mortar is exposed to the outside, deterioration proceeds, and as the deterioration proceeds, it proceeds to the inside of the concrete and the reinforcing bar is corroded. When the reinforcing bar is corroded, the volume of the reinforcing bar expands, and the volume expansion of the reinforcing bar causes cracks in the interior of concrete and eco-friendly high-durability polymer mortar, and decreases the bonding strength of the reinforcing bar, the peeling of the coated concrete, and the decrease in the strength of the reinforcing bar. In the end, it causes a crisis of the entire structure.

On the other hand, since most concrete and repair materials are porous, they absorb moisture or moisture, and at temperatures below the freezing point, the absorbed moisture freezes and cracks occur due to freezing and expansion of moisture. If freezing and thawing are repeated, cracks also progress accordingly, and when this action advances inside, corrosion and deterioration of reinforcing bars are accompanied, causing a problem of deteriorating the durability of the structure.

As a method to solve the above problems, a surface protective coating is applied to the surface. Conventionally, an absorption inhibitor has been used by emulsifying paraffinic hydrocarbon compounds and fatty acid oils as liquid absorption inhibitors for concrete surface coating. Difficult to improve durability.

The present invention is to improve this and to apply a surface protective coating having the above-described composition.

2 is a flow chart showing a cross-section recovery method capable of pouring in water using a highly durable polymer mortar according to an embodiment of the present invention. 2, surface treatment and reinforcement rust removal (chipping operation) is performed (S21).

More specifically, as a pretreatment process for the repair surface, a chipping process is performed on the surface as a grooving operation for reclaiming the surface of the concrete structure to be reinforced, so it is a process that can integrate the environmentally high-durability polymer mortar with the existing underground structure. By performing grooving through work, it creates an optimal bonding environment and enables high-quality construction. To do this, first check the construction location, perform grooving (groove) work, and then remove rust from the rebar exposed to the outside of the concrete.

After the step (S21), a high-pressure water washing (removing foreign matter) process is performed (S22).

That is, after the step (S21), when the surface is cleaned by a parch operation and rust removal is completed, it is preferable to sequentially perform a process of removing foreign substances through high-pressure water washing.

After the step (S22), the reinforcing bar rust prevention paint application (reinforcing bar rust prevention) is performed (S23).

In other words, a rust-removing rust inhibitor is applied, but the rust-removing rust inhibitor is mainly composed of phosphoric acid, a specific gravity of 1.18 to 1.28, and a drying property of 1 to 2 hours (15 to 30°C). It neutralizes the corroded part of the exposed reinforcing bar to further remove rust and prevents corrosion of the rebar by acid resistance.

After step (S23), the old and new adhesive is applied (S24).

Here, the same old and new adhesive used in step S13 in FIG. 1 may be applied. That is, as an embodiment of the present invention, it is possible to apply new and old adhesives corresponding to various materials or made of Barra Emulsion 57, which has a mortar reinforcement effect and strong adhesion, on the surface-treated repair surface.

After step (S24), the environment-friendly high durability polymer mortar is placed (S25).

That is, the environment-friendly, highly durable polymer mortar having the composition in the above-described manner is poured onto the new and old adhesive coated surface.

After step (S25), the surface protection coating is applied (S26).

It is preferable to use the same thing as sayodine in the step (S15) in FIG. 1 as the surface protective coating used herein.

As described above, in the present specification and drawings, a preferred embodiment of the present invention has been disclosed, and although specific terms are used, this is only used in a general meaning to easily explain the technical content of the present invention and to aid understanding of the invention. , It is not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is obvious to those of ordinary skill in the art that other modified examples based on the technical idea of the present invention may be implemented.

Claims (5)

A first step of performing a surface treatment process on the target surface;
A second step of performing a high-pressure water washing process on the surface-treated area;
A third step of applying an old and new adhesive to the washed area;
A fourth step of performing an eco-friendly, highly durable polymer mortar pouring process in the area where the old and new adhesives are applied; And
Characterized in that it includes; a fifth step of applying a surface protection coating agent,
The eco-friendly and highly durable polymer mortar
Cement and blending material, fiber, metakaolin, polymer, and non-separable binder in water, wherein the fiber is a natural coir fiber,
The polymer is a mixture of 10 to 20% by weight of EVA (Ethylene-vinyl acetate) resin and 80 to 90% by weight of an acrylic re-emulsifying resin, but the acrylic re-emulsifying resin is 80 to 90 parts by weight of an acrylic polymer and a crosslinkable functional group. A pre-emulsion comprising 0.1 to 5 parts by weight of a reactive anionic emulsifier and a nonionic emulsifier, 0.01 to 1 parts by weight of a polymerization initiator, and 45 to 50 parts by weight of water is polymerized based on 100 parts by weight of the total monomer consisting of 10 to 20 parts by weight of the eggplant monomer. The obtained acrylic emulsion polymerized product is used, and the monomer having a crosslinkable functional group is characterized by using one or two or more of acrylic acid, methacrylic acid, itaconic acid, and maleic acid,
The surface protection coating agent consists of 25 to 27 parts by weight of epoxy resin, 10 to 13 parts by weight of polyurethane resin, 2 to 3 parts by weight of flame retardant, and 1 to 2 parts by weight of crosslinking agent based on 100 parts by weight of flame-retardant silicone adhesive solution, and an amine-based curing agent It consists of, characterized in that it further comprises a functional filler made of a mixture of silica powder and expandable graphite in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the surface protection coating agent
A surface repair method that can be poured underwater using an eco-friendly, highly durable polymer mortar.
A first step of performing surface treatment and rust removal on the target surface;
A second step of performing a high-pressure water washing process on the surface-treated and rust-removed areas;
A third step of applying a reinforced anti-rust paint to the washed area;
A fourth step of applying an old and new adhesive to the area where the reinforced anti-rust paint is applied;
A fifth step of performing an eco-friendly and highly durable polymer mortar casting process in the area where the old and new adhesives are applied; And
Characterized in that it includes; a sixth step of applying a surface protection coating agent,
The eco-friendly and highly durable polymer mortar
Cement and blending material, fiber, metakaolin, polymer, and non-separable binder in water, wherein the fiber is a natural coir fiber,
The polymer is a mixture of 10 to 20% by weight of EVA (Ethylene-vinyl acetate) resin and 80 to 90% by weight of an acrylic re-emulsifying resin, but the acrylic re-emulsifying resin is 80 to 90 parts by weight of an acrylic polymer and a crosslinkable functional group. A pre-emulsion comprising 0.1 to 5 parts by weight of a reactive anionic emulsifier and a nonionic emulsifier, 0.01 to 1 parts by weight of a polymerization initiator, and 45 to 50 parts by weight of water is polymerized based on 100 parts by weight of the total monomer consisting of 10 to 20 parts by weight of the eggplant monomer. The obtained acrylic emulsion polymerized product is used, and the monomer having a crosslinkable functional group is characterized by using one or two or more of acrylic acid, methacrylic acid, itaconic acid, and maleic acid,
The surface protection coating agent consists of 25 to 27 parts by weight of epoxy resin, 10 to 13 parts by weight of polyurethane resin, 2 to 3 parts by weight of flame retardant, and 1 to 2 parts by weight of crosslinking agent based on 100 parts by weight of flame-retardant silicone adhesive solution, and an amine-based curing agent It consists of, characterized in that it further comprises a functional filler made of a mixture of silica powder and expandable graphite in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the surface protection coating agent
Sectional restoration method that can be poured underwater using eco-friendly, highly durable polymer mortar. delete delete delete

Images