Surface Protective Composition Responsive to Concrete Behavior and Method for Protecting Concrete Structure Surfaces Using the Same

Abstract

The present invention relates to a surface protective agent composition that responds to concrete behavior and a method for protecting the surface of a concrete structure using the same. More specifically, it relates to a method for protecting a concrete structure by coating the surface of a deteriorated and corroded concrete structure with a paint composition capable of responding to the shrinkage and expansion rate of concrete exposed to severe external temperature changes, such as bridges or road traffic facilities.

Description

Technology Field

[0001] The present invention relates to a surface protective agent composition that responds to concrete behavior and a method for protecting the surface of a concrete structure using the same. More specifically, it relates to a method for protecting a concrete structure by coating the surface of a deteriorated and corroded concrete structure with a paint composition capable of responding to the shrinkage and expansion rate of concrete exposed to severe external temperature changes, such as bridges or road traffic facilities. Background Technology

[0003] Generally, if building structures, particularly those made of concrete, are left in their raw state without surface treatment, moisture penetrates through fine cracks on the concrete surface. During the winter, this penetrated moisture freezes and expands in volume, thereby accelerating the cracking process. In concrete structures where cracking has progressed, not only does the strength of the concrete itself decrease, but the internal rebar also comes into contact with moisture and corrodes. As the corrosion of the internal rebar progresses, the strength of the concrete structure rapidly declines, shortening its lifespan and increasing maintenance costs. Furthermore, as durability deteriorates over time, the structure eventually loses its function as a building.

[0004] In particular, the shrinkage and expansion behavior of concrete, which occurs repeatedly due to large daily or seasonal temperature changes such as those in bridges or road traffic facilities, weakens the durability of concrete structures and accelerates the progression of cracks, thereby shortening the lifespan of the structures.

[0005] To prevent the weakening of the durability of such concrete structures, methods involving the application of anti-absorption agents or coating solutions to the surface of the concrete are used. Previously, anti-absorption agents composed of paraffinic hydrocarbon compounds or fatty acid oils were utilized; however, securing sufficient penetration depth was difficult, and the effectiveness in improving durability was limited. Alternatively, water-repellents or anti-absorption agents manufactured by diluting silicone resins or oils in organic solvents were used; however, due to the fluidity inherent in the solvents and the resulting pollution issues and adverse effects on the human body, their use is currently restricted.

[0006] In addition, the above coating solution has been used by mixing fillers with acrylic resin-based polymers, but it is insufficient in terms of physical properties such as adhesion strength, durability, and compressive strength to the base concrete.

[0007] In particular, existing coating methods are fundamentally methods that block moisture through the process of forming a film using organic materials. While the physical properties of the surface protective agent itself may be highly evaluated due to differences in the fundamental composition of the materials, there are limitations to the protection of concrete resulting from this. This is because there is a fundamental limitation in that the lifespan of the coating agent is not long when considering seasonal changes, as there is a difference of up to 10 times in the coefficient of thermal expansion between cement concrete, a representative inorganic material, and existing surface protective agents (coating agents) that are commonly used as raw materials, such as epoxy and acrylic.

[0008] The conventional patented technologies related to protecting the surface of concrete structures are as follows.

[0009] First, Korean Patent Publication No. 2008-0094427 proposed a technology regarding a coating agent that improves adhesion to a substrate by using blast furnace slag, which has high affinity for iron and cement, as a filler, increases flexibility by adding a flexible resin to prevent separation from the substrate surface and increase vibration resistance, and improves adhesion to a substrate by using an alkali metal hydroxide as a curing agent to lower the curing speed.

[0010] In addition, Korean Registered Patent No. 10-0937632 proposed a technology regarding a coating agent that improves chemical resistance and antifungal resistance, along with stain resistance, by adding a fluorine-based surfactant with excellent antistatic and dust adhesion properties to the surface of the coating film to solve the problem of poor resistance to contamination in existing paint compositions.

[0011] However, while conventional coating agents have made some advancements in terms of physical properties such as adhesion strength and physical properties such as stain resistance and chemical resistance, there is no technology that has been researched or proposed to enhance durability against behaviors such as severe daily and seasonal shrinkage and expansion of concrete structures. Specifically, there is no situation where technology development regarding concrete behavior-responsive coating agents capable of reducing stress concentration in the coating layer due to deformation caused by repeated shrinkage and expansion of concrete structures due to changes in ambient temperature, solar condensation, freezing / thawing, etc., and the resulting cracking, delamination, spalling, and reduced durability of the structure has not yet been disclosed or proposed.

[0012] <Related Prior Art Literature>

[0013] Republic of Korea Registered Patent No. 10-0632089

[0014] Republic of Korea Registered Patent No. 10-0167858

[0015] Republic of Korea Registered Patent No. 10-0536471

[0016] Republic of Korea Registered Patent No. 100835842 The problem to be solved

[0018] The present invention was developed to solve the problems of conventional concrete surface protection agents (coating agents) as described above, and as a technology to enhance durability against behaviors such as severe daily and seasonal shrinkage and expansion of concrete structures, it aims to provide a concrete behavior-responsive coating agent (surface protection agent composition) and a surface protection method for concrete structures using the same, which can reduce stress concentration in the coating layer due to deformation caused by repeated shrinkage and expansion of concrete structures due to changes in ambient temperature, solar condensation, freezing / thawing, etc., and thereby reduce cracking, peeling, spalling, and reduced durability of the structure. means of solving the problem

[0020] To achieve the above objectives, the present invention

[0021] (a) a step of preparing a coating composition for protecting the surface of a concrete structure, wherein the coating composition for protecting the surface of a concrete structure comprises 10 to 50 parts by weight of a first acrylic mixture having a glass transition temperature (Tg) of -20 to 20°C, 10 to 50 parts by weight of a second acrylic mixture having a glass transition temperature (Tg) of 45 to 70°C, 1 to 10 parts by weight of an alkoxysilane hydrolysate, 0.05 to 5 parts by weight of an initiator, and 0.05 to 20 parts by weight of an emulsifier.

[0022] A step of preparing a coating composition for protecting the surface of a concrete structure comprising 0.5 to 10 parts by weight of plaster, 0.5 to 10 parts by weight of limestone, 0.1 to 10 parts by weight of an admixture, and 0.5 to 10 parts by weight of plate-shaped talc;

[0023] (b) a step of surface preparation using a surface treatment device on the surface of the concrete structure to be constructed; and

[0024] (c) A protective coating method for the surface of a concrete structure, comprising the step of applying and curing the protective coating composition for the surface of a concrete structure prepared in (a) to the surface of the prepared construction target.

[0025] In one embodiment of the present invention, the first acrylic mixture is characterized by being composed of a mixture of 50 to 70 weight% of one or two types selected from n-butyl acrylate and 2-ethylhexyl acrylate, 20 to 40 weight% of methyl methacrylate, and 1 to 10 weight% of one or more types selected from acrylic acid, hydroxyethyl acrylate, and glycidyl methacrylate.

[0026] In addition, in one embodiment of the present invention, the second acrylic mixture is characterized by being composed of a mixture of 50 to 70 weight% of one or two types selected from methyl methacrylate and styrene, 20 to 40 weight% of one or two types selected from n-butyl acrylate and 2-ethylhexyl acrylate, and 1 to 10 weight% of one or more types selected from acrylic acid, hydroxyethyl acrylate, and glycidyl methacrylate.

[0027] In addition, in one embodiment of the present invention, the admixture is characterized by being formed by mixing 0.1 to 7.0 parts by weight of an amino alcohol-based compound with 100 parts by weight of a composition obtained by mixing lime desulfurization dust in a ratio of 40 to 90 parts by weight and STS converter slag in a ratio of 2 to 18 parts by weight.

[0028] In addition, in one embodiment of the present invention, the coating composition for protecting the surface of a concrete structure is characterized by further including 1 to 5 parts by weight of one or more additives selected from the group consisting of defoaming agents, dispersing agents, cationic wetting agents, leveling agents, surface tension lowering agents, shrinkage reducing agents, surface flowability regulators, retarders, antibacterial agents, and inorganic pigments.

[0029] In addition, in one embodiment of the present invention, when applying the concrete structure surface protection coating composition prepared in (a) to the concrete construction surface in step (c), the application is characterized by using a dedicated high-pressure spray equipment equipped with a high-pressure airless pump and a spray gun.

[0030] In addition, in one embodiment of the present invention, when applying the coating composition for protecting the surface of a concrete structure prepared in (a) to the surface to be treated in step (c), the application is characterized by using a roller or a brush, or using a safety vest for spraying the coating agent equipped with a spray hose and a spray gun attached to the vest. Effects of the invention

[0032] The concrete behavior-responsive surface protection composition according to the present invention has the effect of significantly reducing defect factors by developing strength greater than practical strength within 4 hours.

[0033] In addition, it offers excellent adhesion and durability to the surface of concrete structures, and particularly excels in properties such as chemical resistance, water resistance, and salt resistance, providing superior surface protection for concrete structures.

[0034] In addition, it can enhance durability against behaviors such as severe daily and seasonal shrinkage and expansion of concrete structures, and in particular, it has the effect of reducing stress concentration in the coating layer due to deformation caused by repeated shrinkage and expansion of concrete structures due to changes in ambient temperature, solar condensation, freezing / thawing, etc., and the resulting cracking, peeling, spalling, and deterioration of durability of the structure.

[0035] Furthermore, it is excellent at preventing carbonation of concrete structures and offers superior wear resistance, which effectively extends the lifespan of the structure. At the same time, it exhibits excellent chemical performance, including carbonation prevention, salt damage prevention, and heavy-duty corrosion protection. Its superior durability allows for reduced maintenance costs, and the absence of chemical odors enables application in enclosed spaces or public areas, thereby enhancing safety and environmental friendliness. Specific details for implementing the invention

[0037] The present invention will be described in more detail below.

[0038] The surface protection method for concrete structures according to the present invention is configured in the following order. That is,

[0039] (a) a step of preparing a coating composition for protecting the surface of a concrete structure, wherein the coating composition for protecting the surface of a concrete structure comprises 10 to 50 parts by weight of a first acrylic mixture having a glass transition temperature (Tg) of -20 to 20°C, 10 to 50 parts by weight of a second acrylic mixture having a glass transition temperature (Tg) of 45 to 70°C, 1 to 10 parts by weight of an alkoxysilane hydrolysate, 0.05 to 5 parts by weight of an initiator, and 0.05 to 20 parts by weight of an emulsifier.

[0040] A step of preparing a coating composition for protecting the surface of a concrete structure comprising 0.5 to 10 parts by weight of plaster, 0.5 to 10 parts by weight of limestone, 0.1 to 10 parts by weight of an admixture, and 0.5 to 10 parts by weight of plate-shaped talc;

[0041] (b) a step of surface preparation using a surface treatment device on the surface of the concrete structure to be constructed; and

[0042] (c) comprises the step of applying and curing the concrete structure surface protection coating composition prepared in (a) to the prepared construction target surface.

[0044] First, the step of manufacturing the coating composition for protecting the surface of the concrete structure is described.

[0045] The coating composition for protecting the surface of a concrete structure according to the present invention comprises 10 to 50 parts by weight of a first acrylic mixture having a glass transition temperature (Tg) of -20 to 20°C, 10 to 50 parts by weight of a second acrylic mixture having a glass transition temperature (Tg) of 45 to 70°C, 1 to 10 parts by weight of an alkoxysilane hydrolysate, 0.05 to 5 parts by weight of an initiator, and 0.05 to 20 parts by weight of an emulsifier.

[0046] It is composed of 0.5 to 10 parts by weight of plaster, 0.5 to 10 parts by weight of limestone, 0.1 to 10 parts by weight of admixture, and 0.5 to 10 parts by weight of plate-shaped talc.

[0048] In step (a) above, the coating composition according to the present invention is characterized by having a multiple glass transition structure comprising two or more polymer phases having different glass transition temperatures (Tg).

[0049] To this end, the coating composition according to the present invention is characterized by simultaneously comprising a first acrylic mixture in a soft polymer phase having a glass transition temperature (Tg) of -20 to 20°C and a second acrylic mixture in a hard polymer phase having a glass transition temperature (Tg) of 45 to 70°C.

[0050] The above different polymer phases may exist in the form of a blend structure, a core-shell structure, or a phase-separated microstructure.

[0051] The first acrylic mixture, which is a soft polymer phase, plays a role in maintaining the flexibility of the protective layer even in a low-temperature environment, improving crack-following ability against shrinkage deformation of concrete, and improving the balance between tackiness and adhesion. In the present invention, the first acrylic mixture may be used as a mixture comprising 50 to 70 weight% of a mixture of one or two types selected from n-butyl acrylate and 2-ethylhexyl acrylate, 20 to 40 weight% of methyl methacrylate, and 1 to 10 weight% of a mixture of one or more types selected from acrylic acid, hydroxyethyl acrylate, and glycidyl methacrylate.

[0052] In addition, the second acrylic mixture, which is a hard polymer phase, plays a role in strengthening the hardness of the coating and increasing physical properties such as heat resistance, wear resistance, and durability, and in particular, it plays a role in suppressing excessive softening of the protective layer in high-temperature environments to improve dimensional stability and physical stability. In the present invention, the second acrylic mixture may be used as a mixture comprising 50 to 70 weight% of a mixture of one or two types selected from methyl methacrylate and styrene, 20 to 40 weight% of a mixture of one or two types selected from n-butyl acrylate and 2-ethylhexyl acrylate, and 1 to 10 weight% of a mixture of one or more types selected from acrylic acid, hydroxyethyl acrylate, and glycidyl methacrylate.

[0053] Conventionally, surface protective agent compositions using acrylic latex had problems in that using a polymer phase with a single glass transition temperature resulted in embrittlement at low temperatures, leading to reduced crack-following ability, and softening at high temperatures, resulting in reduced wear resistance and dimensional stability.

[0054] The present invention aims to improve upon such problems by using an acrylic mixture of a polymer phase having a relatively low Tg and a polymer phase having a relatively high Tg, thereby providing a concrete protective coating agent that can actively respond to the deformation behavior of concrete in both low and high temperature environments while ensuring performance such as mechanical stability and chemical stability as a concrete protective layer.

[0055] In the present invention, it is preferable that the first acrylic mixture and the second acrylic mixture be mixed in a ratio of 10 to 50 parts by weight and 10 to 50 parts by weight, respectively, and when each mixture is mixed within the above range, it is possible to adapt to the deformation behavior due to shrinkage and expansion of concrete and to control cracking.

[0056] Furthermore, in the present invention, the alkoxysilane hydrolysate may be used by forming a silane into a silica gel shape through a sol-gel process, adding methyl methacrylate into the pores of the silica gel thus obtained, and then polymerizing and hydrolyzing the result. In the present invention, the content of methyl methacrylate may be included in a range of 0.5 to 5 parts by weight based on 100 parts by weight of alkoxysilane content.

[0057] In the present invention, the initiator may be t-butyl peroxybenzoate, benzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, t-butyl acetape, or 2,5-dimethylhexyl-2,5-diperoxybenzoate. In the present invention, it is preferable to use the initiator in a range of 0.05 to 5.0 parts by weight. If the content of the initiator is less than 0.05 parts by weight, the polymerization initiation reaction of the resin and monomer is reduced, which ultimately leads to a problem of lower strength characteristics of the coating agent; if it exceeds 5.0 parts by weight, there is a problem of difficulty in efficiently controlling the polymerization reaction.

[0058] In the present invention, the emulsifier serves to facilitate easy mixing of the coating agent with water when water is added to the coating agent composition for protecting the surface of a concrete structure according to the present invention. In the present invention, the emulsifier may include glycerin fatty acid ester, sorbitan fatty acid ester, or polyglycerin fatty acid ester. In the present invention, it is preferable to use the emulsifier in a range of 0.05 to 5.0 parts by weight. If the content of the emulsifier is less than 0.05 parts by weight, there is a problem that the coating agent is difficult to mix easily with water when mixed with water, and if it exceeds 5 parts by weight, there is a problem that strength and adhesion performance are difficult to achieve.

[0059] In addition, the coating composition for protecting the surface of a concrete structure in the present invention comprises 0.5 to 10 parts by weight of plaster, 0.5 to 10 parts by weight of limestone, 0.1 to 10 parts by weight of an admixture, and 0.5 to 10 parts by weight of plate-shaped talc.

[0060] In the present invention, the plaster serves to facilitate the easy mixing of components included in the powder component with the liquid component. It is preferable that the plaster be included in a range of 0.5 to 10 parts by weight. Accordingly, if the content of the plaster is less than 0.5 parts by weight, there is a problem that it is difficult to easily mix various components included in the powder component with the liquid component, and if it exceeds 10 parts by weight, there is a problem that strength and chemical resistance are reduced.

[0061] The above limestone serves to assistly improve the adhesion of the coating composition for protecting the surface of a concrete structure according to the present invention. It is preferable that the above limestone be included in a range of 0.5 to 10 parts by weight. If the content of the above limestone is less than 0.5 parts by weight, the effect of improving the adhesion of the coating agent is reduced, and if it exceeds 10 parts by weight, there is a problem of reduced chemical resistance.

[0062] In the present invention, the admixture is characterized by being formed by mixing 0.1 to 7.0 parts by weight of an amino alcohol-based compound with 100 parts by weight of a composition obtained by mixing lime desulfurization dust in a ratio of 40 to 90 parts by weight and STS converter slag in a ratio of 2 to 18 parts by weight.

[0063] In the present invention, the lime desulfurization dust is discharged as a byproduct from the desulfurization process of the steel mill. Specifically, in order to remove sulfur (S) contained in molten iron produced in a blast furnace of an integrated steel mill, a desulfurization auxiliary material such as lime is introduced into the upper part of the molten iron and stirred to promote a reaction between the sulfur and the desulfurization auxiliary material, thereby removing the sulfur contained in the molten iron. Dust is generated during this desulfurization process, and this is referred to as lime desulfurization dust.

[0064] The above lime desulfurization dust is composed mainly of CaO, Ca(OH)2 and CaSO4 components and is a strong alkaline substance with a pH of 11.5 or higher. When used together with blast furnace slag, it acts as an alkali and sulfate stimulant and has the property of being able to manifest the latent hydraulic properties of the blast furnace slag.

[0065] It is preferable that the above lime desulfurization dust be mixed in an amount of 40 to 90 parts by weight in the admixture of the present invention, but if it is less than 40 parts by weight, it is difficult to develop latent hydraulic properties, and if it exceeds 90 parts by weight, it may be difficult to develop strength.

[0066] In addition, STS converter slag, a type of steelmaking slag, has C as its main crystalline phase. 12 It is A7, C2S, and the main components are CaO and SiO2 (CaO content 50~55 wt%, SiO2 content 20~25 wt%).

[0067] The main components of the above lime desulfurization dust and STS converter slag participate in the hydration reaction, and the calcium hydroxide generated by hydration contributes to the activation of the latent hydraulic reaction of the blast furnace slag fine powder.

[0068] In addition, the CaO in the above lime desulfurization dust and STS converter slag is synthesized into ettringite through the progress of the hydration reaction, and as concrete volume expansion occurs, drying shrinkage is reduced. MgO contained in the above STS converter slag at 80~85 wt% also transforms into Mg(OH)2 when it comes into contact with mixing water (H2O), causing concrete volume expansion and contributing to the alleviation of drying shrinkage.

[0069] However, since an excessively high proportion of MgO in the binder composition may affect long-term safety, it is preferable that the STS converter slag content in the admixture according to the present invention be included in the range of 2 to 18 parts by weight.

[0070] In addition, in the present invention, the admixture is formed by additionally mixing 0.1 to 7.0 parts by weight of an amino alcohol-based compound based on 100 parts by weight of the composition formed by mixing in the above ratio.

[0071] In the present invention, the amino alcohol-based compound plays a role in promoting the elution of calcium ions, and the calcium ions eluted at this time can induce the CSH nucleation.

[0072] In the present invention, the amino alcohol-based compounds are tetra(hydroxypropyl)ethylenediamine (THPED), tri(hydroxyethyl)ethylenediamine (THEED), and N-(2-hydroxyethyl)ethylenediamine (HEEDA). One or more mixtures selected from N-(2-hydroxyethyl)ethylenediamine may be used.

[0073] In the present invention, it is preferable that the amino alcohol-based compound be included in a range of 0.1 to 7.0 parts by weight based on 100 parts by weight of the composition obtained. If the amino alcohol is less than 0.1 parts by weight, the effect of causing calcium ions to leach out is reduced, and if it exceeds 7.0 parts by weight, the reactivity may decrease even if a large amount of calcium ions are leached out, so the efficiency may decrease.

[0074] Furthermore, in the present invention, since the plate-like talc component has a plate-like structure, it generates a layered reinforcing effect within the coating composition, thereby improving wear resistance and scratch resistance, and improving compressive and flexural strength. Additionally, as the talc particles are arranged in layers, the tortuous path effect that lengthens the moisture movement path can result in the inhibition of moisture penetration, enhanced waterproofing performance, and improved concrete protection performance.

[0075] In addition, the above-mentioned plate-shaped talc improves film flowability and reduces sagging due to its viscosity-regulating effect (increase in thixotropy), and consequently plays a role in enabling the stabilization of coating thickness and the formation of a uniform coating film.

[0076] In addition, it disperses the drying shrinkage of acrylic coating agents to reduce drying shrinkage and suppress the occurrence of microcracks, and due to its low thermal expansion, it reduces deformation during temperature changes and improves thermal stability, thereby enhancing heat resistance and dimensional stability.

[0077] In the present invention, it is preferable to use the plate-shaped talc in a range of 0.5 to 10 parts by weight.

[0078] In addition, it may include one or more additives selected from the group consisting of defoaming agents, dispersing agents, cationic wetting agents, leveling agents, surface tension lowering agents, shrinkage reducing agents, surface flowability controlling agents, retarders, antimicrobial agents, and inorganic pigments in a range of 1 to 5 parts by weight.

[0079] In addition, a flame retardant may be additionally included to provide a flame-retardant effect after coating, and the flame retardant may be one or a mixture of two or more of antimony molybdate, aluminum hydroxide, molybdenum oxide, and magnesium hydroxide. In particular, aluminum hydroxide (Al(OH)3) transforms into activated alumina when heated to 500°C or higher, thereby possessing adsorption performance. It adsorbs harmful substances such as dioxins and hydrogen chloride gas (HCl) generated during combustion, and undergoes an endothermic reaction during thermal decomposition, providing a cooling effect. It also exhibits excellent water and acid resistance as a non-flammable material, and the flame retardant effect can be improved by using flame retardants in combination.

[0080] In addition, the coating composition for protecting the surface of a concrete structure according to the present invention may include a filler in a range of 30 to 50 parts by weight. The filler is characterized by having a particle size of 2 μm or less and may be a group consisting of silicon dioxide (SiO2), barium sulfate (BaSO4), aluminum oxide (Al2O3), calcium carbonate (CaCO3), talc, or a mixture thereof.

[0081] In addition, the coating composition for protecting the surface of a concrete structure according to the present invention may include 10 to 20 weight percent of a non-reactive diluent selected from the group consisting of dodecylphenol, benzyl alcohol, propylene glycol monomethyl ether, and mixtures thereof.

[0083] In the present invention, the coating composition for protecting the surface of a concrete structure may additionally include a functional filler.

[0084] A mixture of silica powder and expansive graphite can be used as the above functional filler.

[0085] As the silica powder, one or more types selected from colloidal silica, fumed silica, and micronized silica may be used.

[0086] The above functional filler plays a role in enhancing physical effects by further increasing the binding effect of the surface protective agent (coating agent) composition. In the present invention, it is preferable that the silica powder and expandable graphite be mixed in a weight ratio of 100:50 to 200.

[0087] In addition, while this concrete surface protection coating composition can be used alone, for areas requiring particularly high levels of neutralization prevention, chloride ion penetration resistance, and water permeability, finishing the surface with an organosilane can be expected to increase durability due to enhanced water-repellent effects.

[0088] That is, a colloidal solution in which silica powder alone or a mixture of expandable graphite powder is dispersed in a solvent can be processed by dispersing it in an organic silane and 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 solution of silica powder alone or a mixture of expandable graphite powder to form organic groups on the surface of the powder particles within the solution, and the solution is passed through a reactor to form powder surface-treated with organic groups through dehydration and condensation reactions. At this time, the solution is one in which silica powder or expandable graphite powder is dispersed in a colloidal state within a solvent such as water or alcohol, and it is preferable that the solution comes into contact with the organic silane in a colloidal solution state.

[0089] Specific examples of the above-mentioned organosilanes include dimethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and tetraethoxysilane. In this case, the powder surface is treated with an organosilane by stirring at room temperature for about 1 to 10 hours to form an inorganic material with organic groups, and then passing it through a reactor. At this time, the reactor is a heating device in which the temperature is raised to 100 to 300°C and a dehydration and condensation reaction is carried out between the solvent and the inorganic material with organic groups for 1 to 10 hours to produce powdered inorganic particles with completed surface treatment.

[0090] The silica powder and expandable graphite powder produced in this way have silane formed on their surface, so they have an excellent binding effect, and accordingly, their durability can be further improved.

[0091] In the present invention, it is preferable that the functional filler be included in a range of 0.1 to 10 parts by weight.

[0093] Concrete surface protection construction according to the present invention is carried out using a coating composition for protecting the surface of concrete structures manufactured with such a composition.

[0094] First, the surface of the concrete structure to be constructed is prepared using a surface treatment device.

[0095] Specifically, the construction surface of the concrete to be repaired is thoroughly cleaned to remove foreign matter, and after high-pressure water washing, concrete repair material (mortar) is filled into depressions or areas where the concrete has detached to perform leveling work. In this process, if there is exposed rebar, it is advisable to treat the rebar first using a separate rust inhibitor.

[0096] After the filling work is completed, the construction is completed by applying the concrete structure surface protection coating composition prepared according to the present invention to the concrete construction surface using methods such as painting, rolling, or spraying, and curing it.

[0097] The coating composition for protecting the surface of a concrete structure according to the present invention provides excellent effects in enhancing durability, weather resistance, surface strength, and water resistance with just a single application; however, to optimally exhibit these functions, it is preferable to reapply it 2 to 3 times. In the present invention, the coating composition for protecting the surface of a concrete structure has a strength of 20 to 1,000 g / m² 2 It is preferable to apply it with a curing thickness of 50㎛ to 5mm.

[0098] At this time, the coating composition for protecting the surface of the concrete structure can be applied to the surface to be treated using painting, rolling, or spraying methods. When applying it two or more times consecutively, a certain drying and curing period is required between applications, usually 6 hours in the summer and about 24 hours in the winter.

[0099] In addition, since the coating agent itself possesses a certain degree of anti-corrosion function in the present invention, it can exhibit anti-corrosion properties without using a separate primer; however, if surface rust is exposed, it is preferable to apply a primer and then apply the coating agent according to the present invention.

[0100] As the primer used in the present invention, a rubber latex-based rust-converting agent may be used, and it is preferable to use a rust-converting agent that does not contain organic solvents.

[0101] In addition, in the present invention, a topcoat may be additionally applied after applying the coating composition for protecting the surface of the concrete structure. At this time, the topcoat used is not particularly limited, and any topcoat generally used in the technical field to which the present invention belongs may be used without limitation.

[0102] In addition, in the present invention, when applying the concrete structure surface protection coating composition prepared in (a) to the concrete construction surface in step (c), it is preferable to apply it using a dedicated high-pressure spray equipment equipped with a high-pressure airless pump and a spray gun.

[0103] This is because the coating composition for protecting the surface of concrete structures according to the present invention contains a large amount of binder components and has high viscosity, so it is preferable to use dedicated high-pressure spray equipment equipped with a high-pressure airless pump and a spray gun (equipped with a special nozzle and capable of high-pressure spraying) rather than general spray equipment.

[0104] At this time, the dedicated high-pressure spray equipment may use special equipment designed to reduce dust by providing a dust reduction device around the nozzle in an elongated vertical shape.

[0105] In addition, in the present invention, when applying the coating composition for protecting the surface of a concrete structure prepared in (a) to the surface to be treated in step (c), it may be applied using a roller or a brush, or by using a safety vest (dedicated) for spraying the coating, which is equipped with a spray hose and a spray gun.

[0106] In the present invention, the safety vest for spraying the coating agent has a leather reinforcing strap attached to the vest, and safety straps that distribute the weight of the hose and safety straps that distribute the weight of the spray gun are connected to the reinforcing strap in the left and right directions, respectively. A vest-attached hose of the same diameter and material as the hose connected to the coating agent supply device (it is preferable for the vest-attached hose to be placed on the back for workability) is connected to the reinforcing strap, and couplers are provided at both ends of the vest-attached hose so that it can be used by connecting the coating agent supply hose connected to the coating agent supply device and the supply hose connected to the spray gun, respectively, using a coupler connection method.

[0107] When using such a safety vest for spraying coating agents, safety can be enhanced by attaching a hose to the vest, and worker fatigue during spraying operations can be reduced. Furthermore, by installing the connection points between the hose and the vest on the left and right sides rather than the front or back of the waist, the worker can be prevented from tripping over the hose while moving. Additionally, since the spray gun is connected to the vest, it prevents damage caused by the gun falling. Moreover, because both the inlet and outlet of the coating agent are connected to the vest, the worker does not need to drag the hose by hand, making the work easier.

[0108] In addition, in the present invention, after step (c), a water-repellent coating agent may be additionally coated, and an acrylic urethane-based or siloxane-based water-repellent agent may be used as the water-repellent coating agent.

[0110] The coating composition for surface protection of concrete structures according to the present invention and the construction method for surface protection of concrete structures using the same have been described in detail above.

[0112] The coating composition for surface protection of concrete structures according to the present invention can be used for surface protection of concrete structures in various fields, and can be used for surface protection of slabs, beams, bridge decks, outdoor parking lots, factory floors, columns, walls, and floor surfaces in extreme heat and cold regions, and can be usefully used for bridge piers and columns, road traffic facilities, waterways, rock walls, other marine structures, etc.

[0113] In addition, the coating composition for surface protection of concrete structures according to the present invention has the advantages of excellent adhesion to existing substrates, no neutralization reaction with concrete, water resistance, ozone resistance, chemical resistance, waterproofing, breathability, and no aging caused by oxidation due to ultraviolet rays.

[0114] In addition, the coating composition for protecting the surface of a concrete structure according to the present invention can enhance durability against behaviors such as severe daily and seasonal shrinkage and expansion of the concrete structure, and in particular, by suppressing the peeling and deterioration of the coating layer due to deformation caused by repeated shrinkage and expansion of the concrete structure due to changes in ambient temperature, solar condensation, freezing / thawing, etc., it has the effect of reducing cracks, peeling, spalling, and reduced durability of the structure.

[0115] The coating composition for surface protection of concrete structures according to the present invention exhibits excellent wear resistance and impact resistance due to strength development, inhibits the penetration of carbon dioxide, and blocks water penetration. The coating composition for surface protection of concrete structures according to the present invention is environmentally friendly and free from air pollution due to its low VOC (volatile organic compound) content, exhibits high strength development and excellent early strength, and behaves identically to the base material because cement, which is the same as concrete, is the main material.

[0117] The present invention will be explained in more detail below based on exemplary embodiments. However, the scope of the present invention is not limited by the following embodiments.

[0119] [Example]

[0121] Example 1

[0122] A first acrylic mixture was prepared by mixing 60 wt% of n-butyl acrylate, 35 wt% of methyl methacrylate, 2 wt% of acrylic acid, and 3 wt% of hydroxyethyl acrylate.

[0123] A second acrylic mixture was prepared by mixing 60 wt% methyl methacrylate, 20 wt% n-butyl acrylate, 10 wt% 2-ethylhexyl acrylate, 2 wt% acrylic acid, and 5 wt% hydroxyethyl acrylate.

[0124] A coating composition was prepared by mixing 30 parts by weight of the first acrylic mixture and 30 parts by weight of the second acrylic mixture obtained above with 5 parts by weight of alkoxysilane hydrolysate, 1.0 parts by weight of an initiator (t-butylperoxybenzoate), and 5 parts by weight of an emulsifier (glycerin fatty acid ester), mixing 5 parts by weight of plaster, 7 parts by weight of limestone, 3 parts by weight of an admixture, and 1.0 parts by weight of plate-shaped talc powder, and mixing a certain amount of a dispersant, a shrinkage reducing agent, a retardant, an inorganic pigment, and a filler.

[0125] The above admixture was used by mixing 2.0 parts by weight of an amino alcohol-based compound with 100 parts by weight of a composition obtained by mixing lime desulfurization dust in a ratio of 60 parts by weight and STS converter slag in a ratio of 10 parts by weight.

[0127] Example 2

[0128] The above Example 1 is carried out in the same manner, provided that 60 wt% of 2-ethylhexyl acrylate, 35 wt% of methyl methacrylate, 2 wt% of acrylic acid, and 3 wt% of hydroxyethyl acrylate are mixed to prepare a first acrylic mixture.

[0129] The procedure was carried out by varying only the composition of the second acrylic mixture, which was prepared by mixing 40 wt% methyl methacrylate, 20 wt% styrene, 20 wt% n-butyl acrylate, 10 wt% 2-ethylhexyl acrylate, 2 wt% acrylic acid, and 5 wt% hydroxyethyl acrylate.

[0131] Example 3

[0132] The above example was carried out in the same manner as Example 1, except that 40 parts by weight of the first acrylic mixture and 20 parts by weight of the second acrylic mixture were mixed.

[0134] Example 4

[0135] The above Example 1 was carried out in the same manner, except that 20 parts by weight of the first acrylic mixture and 40 parts by weight of the second acrylic mixture were mixed.

[0137] Comparative Example 1

[0138] A coating composition was prepared by mixing 40 parts by weight of SBR latex resin, 30 parts by weight of a fast-setting binder, 2.0 parts by weight of an initiator, and 5 parts by weight of an emulsifier as powder components, 5 parts by weight of gypsum, 5 parts by weight of plaster, 3 parts by weight of silica fume, 3 parts by weight of fly ash, 7 parts by weight of limestone, and 3 parts by weight of slag, with a certain amount of other inorganic pigments, fillers, shrinkage reducers, retarders, etc.

[0140] Performance evaluation

[0141]

[0142] 1. Chloride ion penetration resistance, freeze-thaw resistance test

[0143] The chloride ion penetration resistance and freeze-thaw resistance of the coating agents for surface protection of concrete structures prepared according to Examples 1 to 4 and Comparative Example 1 were measured.

[0144] The chloride ion penetration resistance was measured 28 days after construction according to the standard of KS F 4936-2008, and the freeze-thaw resistance was measured 28 days after construction according to the standard of KS F 2456-2013, and the results are shown in Table 1 below.

[0145] Sample Chloride ion penetration resistance (Coulombs) Freeze-thaw resistance (relative dynamic elastic modulus) (%) Example 1 425 84.5 Example 2 440 85.8 Example 3 425 85.5 Example 4 435 80.0 Comparative Example 1 458 72.1

[0146] Referring to Table 1 above, the coating composition for surface protection of concrete structures according to the present invention is equivalent to or superior to conventional coatings in terms of chloride ion penetration resistance and freeze-thaw resistance.

[0148] 2. Waterproof test

[0149] The water resistance of the coating agent for protecting the surface of a concrete structure prepared according to Examples 1 to 4 and Comparative Example 1 was measured.

[0150] The above waterproofing properties were measured 28 days after construction according to the standard of KS F 4042-2012, including water permeability, water absorption coefficient, moisture permeability resistance, and length change rate, and the results are shown in Table 2 below.

[0151] Sample Water permeability (g) Water absorption coefficient (kg / m²) 2 h 0.5 ) Moisture permeability resistance (m) Rate of change in length (%) Example 1 0.20 0.05 0.9 -0.011 Example 2 0.25 0.07 1.0 -0.012 Example 3 0.27 0.06 1.1 -0.012 Example 4 0.29 0.07 1.0 -0.011 Comparative Example 1 0.32 0.06 1.2 -0.012

[0152] Looking at the results in Table 2, it can be seen that the degree of moisture penetration in Examples 1 to 4 is reduced compared to Comparative Example 1. This is interpreted as a result indicating the excellent waterproofing performance of the coating composition for protecting the surface of concrete structures according to the present invention.

[0154] 3. Chemical resistance test

[0155] The chemical resistance of the coating compositions for protecting the surface of concrete structures prepared according to Examples 1 to 4 and Comparative Example 1 was measured.

[0156] The measurement method involved treating a coating layer on a concrete structure 28 days after curing with a brine solution having a salt concentration of 35‰ and a 2% sulfuric acid solution, respectively, for 1 hour each day, and then checking whether the coating layer was damaged on a daily basis for 60 days.

[0157] The results are shown in Table 3 below.

[0158] Sample Chemical resistance test (day) brine sulfuric acid solution Example 1 - 80 Example 2 - 65 Example 3 - 70 Example 4 - 59 Comparative Example 1 40 32

[0159] Looking at Table 3 above, it can be seen that in the case of Examples 1 to 4, no surface damage occurred due to the brine treated for 60 days, whereas in the case of Comparative Example 1, surface damage occurred about 40 days after brine treatment. In addition, when treated with a sulfuric acid solution, it can be confirmed that in the case of Examples 1 to 4, no surface damage occurred for about 60 days or more, but in the case of Comparative Example 1, the acid resistance performance against the sulfuric acid solution was lower than that of Example 1.

[0160] This is interpreted as a result supporting the fact that the coating composition for surface protection of concrete structures according to the present invention possesses excellent chemical resistance, particularly acid resistance.

[0162] 4. Coefficient of thermal expansion

[0163] The coefficient of thermal expansion of the coating composition for surface protection of concrete structures prepared according to Examples 1 to 4 and Comparative Example 1 and ordinary concrete was measured.

[0164] Measurements were performed using the ASTM 531-18 method, and the results are shown in Table 4 below.

[0165] coefficient of thermal expansion concrete Example 1 10.2×10 -6 / ℃ 10.0×10 -6 / ℃ Example 2 10.8×10 -6 / ℃ 10.0×10 -6 / ℃ Example 3 10.5×10 -6 / ℃ 10.0×10 -6 / ℃ Example 4 11.0×10 -6 / ℃ 10.0×10 -6 / ℃ Comparative Example 1 25.2×10 -6 / ℃ 10.0×10 -6 / ℃

[0166] As shown in Table 4 above, Examples 1 to 4 according to the present invention have a coefficient of thermal expansion similar to that of concrete compared to Comparative Example 1, so it can be confirmed that phenomena such as spalling and cracking caused by differences in thermal behavior with the base concrete can be improved despite seasonal temperature changes.

Claims

Claim 1 (a) a step of preparing a coating composition for protecting the surface of a concrete structure, wherein the coating composition for protecting the surface of a concrete structure comprises 10 to 50 parts by weight of a first acrylic mixture having a glass transition temperature (Tg) of -20 to 20°C, 10 to 50 parts by weight of a second acrylic mixture having a glass transition temperature (Tg) of 45 to 70°C, 1 to 10 parts by weight of an alkoxysilane hydrolysate, 0.05 to 5 parts by weight of an initiator, 0.05 to 20 parts by weight of an emulsifier, and 0.5 to 10 parts by weight of plaster, 0.5 to 10 parts by weight of limestone, 0.1 to 10 parts by weight of an admixture, and 0.5 to 10 parts by weight of plate-shaped talc; (b) a step of surface finishing the surface of a concrete structure to be treated using a surface treatment device; A protective coating method for the surface of a concrete structure, comprising the steps of: (c) applying and curing the concrete structure surface protective coating composition prepared in (a) onto the prepared surface of the construction target, wherein the admixture is formed by mixing 0.1 to 7.0 parts by weight of an amino alcohol-based compound with 100 parts by weight of a composition obtained by mixing lime desulfurization dust in a ratio of 40 to 90 parts by weight and STS converter slag in a ratio of 2 to 18 parts by weight. Claim 2 A protective coating method for the surface of a concrete structure according to claim 1, wherein the first acrylic mixture comprises 50 to 70 weight% of a mixture of one or two types selected from n-butyl acrylate and 2-ethylhexyl acrylate, 20 to 40 weight% of methyl methacrylate, and 1 to 10 weight% of a mixture of one or more types selected from acrylic acid, hydroxyethyl acrylate, and glycidyl methacrylate. Claim 3 A protective coating method for the surface of a concrete structure according to claim 1, wherein the second acrylic mixture comprises 50 to 70 weight% of a mixture of one or two types selected from methyl methacrylate and styrene, 20 to 40 weight% of a mixture of one or two types selected from n-butyl acrylate and 2-ethylhexyl acrylate, and 1 to 10 weight% of a mixture of one or more types selected from acrylic acid, hydroxyethyl acrylate, and glycidyl methacrylate. Claim 4 delete Claim 5 A protective coating method for the surface of a concrete structure according to claim 1, wherein the coating composition for protecting the surface of a concrete structure further comprises 1 to 5 parts by weight of one or more additives selected from the group consisting of defoaming agents, dispersing agents, cationic wetting agents, leveling agents, surface tension lowering agents, shrinkage reducing agents, surface flowability regulators, retarders, antibacterial agents, and inorganic pigments. Claim 6 A protective coating method for the surface of a concrete structure according to claim 1, wherein, in step (c), when applying the coating composition for protecting the surface of a concrete structure prepared in (a) to the surface to be treated, the application is performed using a dedicated high-pressure spray equipment equipped with a high-pressure airless pump and a spray gun. Claim 7 A protective coating method for the surface of a concrete structure according to claim 1, wherein, in step (c), when applying the coating composition for protecting the surface of a concrete structure prepared in (a) to the surface to be treated, the coating is applied using a roller or a brush, or by using a safety vest for spraying the coating, which is equipped with a spray hose and a spray gun attached to the vest.

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