Cement-free curing artificial aggregate and manufacturing method thereof

Abstract

The present invention relates to cement-free cured artificial aggregate recycled from industrial by-products and a method for manufacturing the same. More specifically, the invention relates to an artificial aggregate and a method for manufacturing the same in which a polymer network structure is imparted to the outer surface to reduce water absorption and improve strength by performing accelerated carbonation and drying curing reaction steps, wherein a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and a liquid comprising acrylic polymer resin and water are used to manufacture the core and outer surface of the artificial aggregate through a cylindrical granulator, and then performing a mixed powder mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and then performing a liquid phase comprising acrylic polymer resin and water. In addition, since the crushing strength is equivalent to or greater than that of conventional soft rock (limestone), it is effective in improving structural durability and partially resolving the problem of natural aggregate shortages by replacing part or all of the natural aggregate in construction components of buildings or civil engineering structures, as well as addressing the issue of industrial byproduct reprocessing.

Description

Technology Field

[0001] The present invention relates to cement-free cured artificial aggregate recycled from industrial by-products and a method for manufacturing the same. More specifically, the invention relates to an artificial aggregate and a method for manufacturing the same in which a polymer network structure is imparted to the outer surface to reduce water absorption and improve strength by performing accelerated carbonation and drying curing reaction steps, wherein a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and a liquid comprising acrylic polymer resin and water are used to manufacture the core and outer surface of the artificial aggregate through a cylindrical granulator, and then performing a mixed powder mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and then performing a liquid phase comprising acrylic polymer resin and water. Background Technology

[0002] In general, among cement concrete mixtures or asphalt concrete (asphalt) mixtures used for construction or building, in the case of a cement concrete mixture using 60 to 70 weight percent of natural aggregate, strength is developed due to silicate minerals and calcium carbonate (CaCO3), which are produced by the calcium-silicate-hydrate (CSH) and alkali-silicate (ASR) reactions between cement and water, with aggregate, cement, admixture, admixture, and water as components.

[0003] In the hydration reaction of concrete, which is composed of representative elements such as cement, aggregate, and water, when cement and water are mixed, the anionically charged particle surfaces become colloidal or gelled. This triggers exothermic dehydration polymerization or hydrolysis reactions, allowing water to penetrate into the particles and proceed with hydration, forming another layer of hydrate inside. As these hydrates bond with each other, the spaces between the cement particles are filled with hydrate, and fine aggregates such as sand are bound together through the setting process. At this time, the chemical formula Ca6Al2(SO4)3(OH), referred to as ettringite 12It forms an alumina-calcium sulfate hydrate mineral composed of ·26H2O, and as time passes, further hydration and aggregate-alkali reactions proceed, filling the pores created by the coarse aggregate and hardening.

[0004] When cement and water are mixed and used as a base to fill the voids created by aggregates, a fluid cement paste is formed. As curing time elapses, this paste loses its fluidity even though it is still in a soft state; this state is called the initial set. The paste continues to solidify until it exhibits a solid-like state, and this state is called the final set. Thus, setting and hardening are caused by the calcium silicate hydrate (CSH) and aggregate-alkali-silicate reaction resulting from the hydration reaction, and through this setting and hardening, a cement concrete solid with the required strength is formed.

[0005] For a typical ordinary Portland cement concrete mixture, the compressive strength measured after 28 days of curing is around 20 MPa, and the design flexural strength of cement concrete slabs for road paving is set to 4.5 MPa or higher.

[0006] On the other hand, in the case of asphalt concrete for road paving (asphalt concrete) using natural aggregates, the composition includes approximately 95% by volume of natural aggregates and approximately 5% by volume of asphalt binder, and strength is developed through the bonding force between coarse aggregates and fine aggregates and the adhesive force of the asphalt binder. The strength standard for asphalt concrete for roads is set as an indirect tensile strength in the range of 0.7 to 0.8 MPa, as an example for asphalt concrete for the surface layer.

[0007] When replacing some or all of the natural aggregates in the above-mentioned cement or asphalt mixture with artificial aggregates, the design standard compressive strength of the mixture containing artificial aggregates is specified to be in the range of 18 to 24 MPa, but the design standard compressive strength or crushing strength of the artificial aggregates themselves is not specified. Therefore, it is necessary to apply the standard compressive strength of ordinary rock (soft rock), which is around 10 MPa, and the basic physical properties of the aggregates, such as the squamousness ratio, water absorption rate, abrasion rate, stability, and specific gravity, must satisfy the specifications according to the application.

[0008] In the case of cement concrete road pavement mixtures, most of the strength is developed through the hydration reaction of aggregates (approximately 60–70% by volume) and cement paste (approximately 30–40% by volume), which is a mixture of cement and water, and the pozzolanic chemical reaction between the alkali and the aggregates. In this case, the level of strength developed is significantly influenced by the silicon dioxide (SiO2) and alumina (Al2O3) content contained in the cement and aggregates. On the other hand, in the case of asphalt concrete, adhesive bonding with the aggregates is developed by the adhesive force of the asphalt binder, which is a hydrocarbon mixture, and approximately 80% of the mechanical bonding strength (Interlocking Force) between the aggregates is developed.

[0009] Even in the case of cement concrete mixtures, they contain aggregates of various sizes and are designed in accordance with the particle size distribution specified in the specifications. Although the slump amount, air content, water and cement ratio, and curing temperature of the unhardened concrete are factors that influence strength development, the bonding force between aggregates according to the aggregate particle size distribution has a relatively very small effect on the strength of the mixture compared to asphalt concrete mixtures.

[0010] In particular, the bonding strength between aggregates is a critical factor in maintaining durability above an appropriate level in the composition of asphalt road paving mixtures. To maximize the bonding strength between aggregates, the aggregate gradation should be managed by defining the range in the specifications according to the intended use of the mixture, and the shape of the aggregates themselves must also be adjusted to meet standards. In the case of artificial aggregates, it is desirable to produce them with a shape in the range of 1 to 1.2, satisfying the above standards for the length-to-diameter ratio. Major advantages of producing single-gradation artificial aggregates include the elimination of a separate crushing process and the generation of spoil, as well as the possibility of producing artificial aggregates with a flattened-to-slenderness ratio relatively close to 1.0.

[0011] However, since the management of aggregates in asphalt concrete mixtures is mostly based on mixed particle sizes with large upper and lower ranges, it is very difficult to achieve consistent mixture durability. Referring to the case of SMA (Stone Mastic Asphalt) developed in Germany, which manages aggregate sizes as single particles offers a significant advantage in exhibiting bonding strength between aggregates, it has disadvantages such as high costs and the need to add cellulose fibers to prevent asphalt binder flow.

[0012] In the case of SMA used in domestic highways, asphalt binders are modified to improve resistance to deformation or long-term fatigue cracking of the mixture; however, quality control of the mixture, particularly regarding aggregate gradation, is difficult, requiring attention to the variability of the durability performance of the final mixture. On the other hand, artificial aggregates have a significant advantage in that they allow for easy control of the mixture's gradation, as it is easy to produce artificial aggregates of a single gradation by adjusting the angle and rotation speed of the cylindrical granulator during production.

[0013] In addition, most existing artificial aggregates require firing at temperatures of 1,000°C or higher, which entails high energy consumption and high costs. Furthermore, since the uniaxial compressive strength of the aggregate itself is 5 MPa or less, there are difficulties in replacing ordinary soft rock, which is subject to the compressive strength regulation of around 20 MPa and the standard of compressive strength of the aggregate itself of 10 MPa or more, in the case of aggregate mixtures specified for structural use.

[0014] Accordingly, the inventors have completed the present invention by developing a cement-free cured artificial aggregate and a method for manufacturing the same, which can partially solve the problem of natural aggregate shortage by reprocessing and recycling industrial by-products such as blast furnace slag, steelmaking slag, bottom ash, and calcium carbonate as raw materials, and also has the effect of reducing carbon dioxide through low thermal energy usage and improving the durability of the mixture by increasing the bonding strength between aggregates. Prior art literature

[0015] Korean Registered Patent Publication No. 10-2488356 The problem to be solved

[0016] The present invention aims to provide a cement-free cured artificial aggregate and a method for manufacturing the same, which can partially resolve the problem of reprocessing industrial by-products (blast furnace slag, steelmaking slag, bottom ash, calcium carbonate) and the problem of a shortage of natural aggregates of a specific size during the construction of cement concrete or road paving for building and construction, reduce carbon dioxide by using lower thermal energy than the conventional method of manufacturing artificial aggregates by high temperature firing at over 1,000°C, increase the fluidity of the concrete mixture and reduce the water-to-cement ratio by partially substituting natural aggregates with artificial aggregates having an aspect ratio close to 1.0, thereby increasing strength and durability performance, and improve the durability of the mixture by increasing the bonding strength between aggregates in organic asphalt mixtures.

[0017] However, the technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0018] According to one embodiment of the present invention, an artificial aggregate composition is provided comprising a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and a liquid phase comprising an acrylic polymer resin and water.

[0019] In the present invention, the mixed powder may be an artificial aggregate composition comprising 25 to 55 weight% of blast furnace slag; 15 to 35 weight% of fly ash; 3 to 10 weight% of sodium carbonate; 10 to 20 weight% of calcium hydroxide; and 0.3 to 0.5 weight% of a setting retardant.

[0020] In the present invention, the artificial aggregate composition may comprise 10 to 20 parts by weight of a filler mixed with calcium carbonate and steel slag in a 1:1 weight ratio with respect to 100 parts by weight of the mixed powder.

[0021] In the present invention, the acrylic polymer resin comprises 30 to 60 wt% styrene, 10 to 30 wt% 2-hydroxyethyl acrylate, 10 to 30 wt% butyl acrylate, 0.5 to 5 wt% reactive emulsifier, 1 to 3 wt% sodium dodecyl sulfate, 1 to 2 wt% potassium persulfate, and 0.5 to 5 wt% vinyl silane, and the acrylic polymer resin may be an artificial aggregate composition characterized by being mixed with ion-exchanged water in a weight ratio of 5:5.

[0022] In the present invention, the artificial aggregate composition may contain 30 to 35 parts by weight of water with respect to 100 parts by weight of the mixed powder.

[0023] In the present invention, the artificial aggregate composition may comprise 10 to 15 parts by weight of sodium hydroxide, 1 to 3 parts by weight of sodium silicate, and 1 to 3 parts by weight of acrylic polymer resin, based on 100 parts by weight of water.

[0024] According to another embodiment of the present invention, the method for manufacturing artificial aggregate may comprise: a dry mixing step of a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; a wet mixing step of introducing a liquid comprising an acrylic polymer resin and water into the mixed powder; a granulation step of introducing the product of the wet mixing step into a cylindrical granulator to form a core and a shell of artificial aggregate; an accelerated carbonation step of introducing the molded artificial aggregate into a curing machine after producing the artificial aggregate core and shell through the granulation step, and then adding carbon dioxide; and a drying and curing reaction step of 60 to 80°C for 6 to 8 hours.

[0025] In the present invention, the granulation step utilizes the product of the wet mixing step,

[0026] A method for manufacturing artificial aggregate may include the step of manufacturing fine aggregate of 2 to 5 mm in a first cylindrical pan with an inclination of 30 to 35° and a rotational speed of 30 to 35 rpm; or the step of manufacturing coarse aggregate of 10 mm or more in a second cylindrical pan with an inclination of 40 to 45° and a rotational speed of 30 to 35 rpm.

[0027] In the present invention, the accelerated carbonation step may be a method for manufacturing artificial aggregate performed for 6 to 8 hours in an environment with a carbon dioxide concentration of 15 to 20%, a temperature of 40 to 80°C, a pressure of 1 to 2 atmospheres, and a relative humidity of 40 to 60%. Effects of the invention

[0028] The cured artificial aggregate according to the present invention exhibits a crushing strength equivalent to or greater than that of ordinary soft rock (limestone), so it can partially solve the problem of industrial by-product reprocessing and the problem of natural aggregate shortage by replacing part or all of the natural aggregate in construction members of buildings or civil engineering structures, and it has advantages in terms of environmental and economic aspects as it uses significantly lower carbon dioxide emissions and thermal energy compared to existing artificial aggregates produced by high-temperature calcination at 1,000°C or higher.

[0029] The artificial aggregate according to the present invention is produced through a cement-free bonding and curing process utilizing industrial by-products, and forms a dense structure by imparting accelerated carbonation and an eco-friendly polymer network structure to the outer layer, thereby minimizing environmental damage caused by leaching of ions from unsaturated industrial by-products due to contact with external moisture or the leaching of heavy metals.

[0030] Since the artificial aggregate according to the present invention is molded into a spherical shape with an aspect ratio and slenderness ratio close to 1.0, when about 10% to 50% of the aggregates of 5 to 10 mm size, which are intermediate aggregates between coarse and fine aggregates, are replaced among the aggregates in a cement concrete mixture for civil engineering construction or building construction, workability is improved by reducing friction between aggregates during mixing, and the strength of the mixture is improved by reducing the water-cement ratio.

[0031] In the case of a mixture in which approximately 10% to 50% of the aggregate is replaced with an artificial aggregate according to the present invention, which is an intermediate size between the coarse aggregate and fine aggregate of natural aggregate in an asphalt mixture for road paving, the bonding strength between the aggregates can be increased, thereby significantly improving the durability of the mixture.

[0032] According to the present invention, by using steelmaking slag, a byproduct of the steel industry, as a raw material, it is possible to simultaneously solve the problem of recycling steelmaking slag, a byproduct of the steel industry, and the problem of the shortage of natural aggregates that are gradually being depleted, and there is an effect of reducing carbon dioxide emissions due to low energy costs.

[0033] According to the present invention, by mixing steelmaking slag with blast furnace slag and an alkali activator, a compressive strength of 30 MPa or more is achieved, which has the effect of having a strength greater than that of natural crushed stone aggregate.

[0034] According to the present invention, when the artificial aggregate of the present invention is used as an aggregate in concrete, asphalt, and concrete secondary product mixtures by partially replacing natural aggregate, the performance can be supplemented and improved compared to the use of natural aggregate. Brief explanation of the drawing

[0035] Figure 1 shows the chemical organic and inorganic chemical reaction structural formulas of an artificial aggregate composition by a vinyl silane coupling agent. Figure 2 is the result of a heavy metal leaching test of a mixture for granulating artificial aggregate according to Manufacturing Example 2 of the present invention. Figure 3 is an image of a stirring and granulation apparatus for artificial aggregate according to an embodiment of the present invention. Figures 4 and 5 are images showing artificial aggregate according to an embodiment of the present invention. FIG. 6 is a standard test specimen for a compressive strength test according to an embodiment of the present invention. FIG. 7 is a cement concrete specimen containing artificial aggregate according to the present invention. FIG. 8 is an asphalt concrete specimen containing artificial aggregate according to the present invention. Specific details for implementing the invention

[0036] Hereinafter, to explain more specifically, examples will be provided for detailed description. However, the following examples are illustrative and the scope of the present invention is not limited thereto.

[0037] According to one embodiment of the present invention, the invention relates to an artificial aggregate composition comprising a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and a liquid phase comprising an acrylic polymer resin and water.

[0038] In the present invention, the mixed powder may comprise 25 to 55 weight% of blast furnace slag; 15 to 35 weight% of fly ash; 3 to 10 weight% of sodium carbonate; 10 to 20 weight% of calcium hydroxide; and 0.3 to 0.5 weight% of a setting retardant.

[0039] In the present invention, with respect to 100 parts by weight of the mixed powder, 10 to 20 parts by weight of a filler mixed with calcium carbonate and steel slag in a 1:1 weight ratio may be included.

[0040] The above-mentioned blast furnace slag and steelmaking slag refer to materials obtained by rapidly or slowly cooling the floating matter on the molten iron resulting from the melting of rock components in iron ore within a blast furnace used to produce iron, and then crushing the recovered material in the form of lumps or sand particles into powder. The present invention utilizes the base properties of silicate (SiO4), alumina (Al2O3), quicklime (CaO), and magnesium oxide (MgO), which are abundantly contained in the blast furnace slag and steelmaking slag used in the invention and promote hydration reactions and aggregate-alkali reactions initiated during the granulation and curing processes of artificial aggregates, thereby aiming to leverage advantages such as strength development, reduction of hydration heat, control of specific gravity, improvement of long-term strength, and increased watertightness.

[0041] In addition, blast furnace slag and steelmaking slag fine powder are latent hydraulic materials that cannot initiate a self-induced hydration reaction. This means that a hardening reaction is initiated through the leaching of ions and the precipitation of insoluble substances via external alkaline stimulation. Conventionally, they were mostly used to replace 20 to 50 weight percent of cement in cement concrete mixtures, but in the present invention, they are used as a cement-free binder, and steelmaking slag containing iron (Fe) is mixed to control the specific gravity of the artificial aggregate.

[0042] Specifically, the blast furnace slag and steelmaking slag may be composed of fine powder, and the fine powder of the blast furnace slag and steelmaking slag has a fineness of 500 to 4,500 cm⁻¹ 2 / g, density 2.7~2.9g / cm³ 3 In addition, the main chemical composition is SiO2, Fe2O3, Al2O3, CaO, and MgO, and the material contains 95 to 97% of the total chemical components. It may be most suitable to be composed of more than 25% CaO and more than 20% SiO2 components for sufficient hydration reaction, and less than 8% MgO components to suppress abnormal expansion.

[0043] The above fly ash refers to a byproduct generated when coal is used as a raw material in a thermal power plant, and involves mixing collected fly ash or bottom ash in a certain ratio or using it as a single component. It is suitable to utilize ash with a silicon dioxide (SiO2) content of 30% or more. Most of the fly ash particles are spherical in shape and reduce frictional resistance during the artificial aggregate granulation process, thereby improving workability. Fly ash and bottom ash are intended to induce sufficient hydration and aggregate alkali reaction on the particle surface through the prior alkali activation disclosed in this invention on the outer shell of the artificial aggregate.

[0044] Specifically, the above fly ash may consist of fly ash fine powder, and the fineness of the fly ash fine powder is 3,000 to 4,500 cm⁻¹ 2 / g, density 1.9~2.3g / cm³ 3 The main chemical composition is SiO2, Fe2O3, Al2O3, CaO, and MgO, and the material contains 95~97% of the total chemical components. It is most suitable to be composed of more than 10% CaO and more than 30% SiO2 components for sufficient hydration reaction, and less than 2% MgO components to suppress abnormal expansion.

[0045] In addition, if the above conditions are met, the fly ash fine powder may include bottom ash fine powder.

[0046] The quicklime and silica (CaO, SiO2) components contained in blast furnace slag, steelmaking slag, fly ash, or bottom ash, which are components of the above-mentioned mixed powder, undergo a dehydration polymerization reaction when mixed with water to additionally produce calcium silicate hydrate (Calcium-Silicate-Hydroxyl) and calcium hydroxide (Ca(OH)2), and utilize a solidification base in which, when hydration occurs, a hydrate such as calcium silicate hydrate is usually produced and then cured to form calcium carbonate (CaCO3).

[0047] The hydration reaction between the main components of slag and ash as described above and water can be represented by the following chemical formula 1.

[0048] [Chemical Formula 1]

[0049] 2(3CaO·SiO2) + 6H2O --> 3CaO·2SiO2·3H2O(C3S2H3) + 3Ca(OH)2.

[0050] The above sodium carbonate (Na2CO3) utilizes the basis in which sodium hydroxide (NaOH) and carbon dioxide (CO2) are generated upon reaction with water, and is intended to improve the degree of aggregate-alkali reaction by preventing chloride generation during the molding of artificial aggregates.

[0051] For example, if the sodium carbonate is included in an amount of less than 3% by weight relative to the total weight of the mixed powder, the amount of chloride synthesis is too small, so the strength improvement effect due to the aggregate-alkali reaction may be negligible, and if it is included in an amount exceeding 10% by weight, excessive cracking due to drying shrinkage may occur due to excessive chloride generation, which may result in a significant decrease in durability.

[0052] The aforementioned calcium hydroxide (Ca(OH)2) refers to slaked lime, which acts as an activating agent for the hydration reaction. By reacting with finely ground blast furnace slag to additionally form hydroxides (CSH), it contributes to the formation of a dense outer shell of the artificial aggregate. Furthermore, as an additive added in a separate weight percentage—in addition to the calcium hydroxide generated by chemical reactions during the wet mixing and granulation stages of the artificial aggregate mixture—it is utilized to enhance the strength of the artificial aggregate by generating calcium carbonate through reactions with calcium ions and carbonate ions during the hydration reaction.

[0053] For example, if the calcium hydroxide is included in an amount of less than 10% by weight relative to the total weight of the mixed powder, a problem may arise where it is difficult to generate sufficient hydroxide due to a lack of dissociated calcium ions and hydroxyl groups, and if it is included in an amount exceeding 20% ​​by weight, a problem may arise where the heat of hydration increases due to excessive hydroxide generation, causing premature drying shrinkage cracks and resulting in reduced durability.

[0054] The above setting retardant refers to a sugar powder which is a disaccharide, and can be used as a single type or in combination from, for example, sucrose, lactose, fructose, etc., and contains a large amount of hydroxyl groups (-OH), so it can be utilized to prevent initial shrinkage cracks in artificial aggregates caused by excessive hydration reactions by suppressing the excessive hydroxide (CSH) generation reaction of artificial aggregates and delaying the setting reaction or pot life. In other words, the hydroxyl groups (-OH) contained in large amounts in the setting retardant slow down the dissociation rate for reaction with other chlorides, thereby serving the function of securing a sufficient pot life for granulation of artificial aggregates.

[0055] For example, if the above setting retardant is included in an amount of less than 0.3% by weight relative to the total weight of the mixed powder, it may be difficult to control the setting time, and if it is included in an amount exceeding 0.5% by weight, the excessive initial setting retardation may suppress the sufficient hydration reaction and the aggregate-alkali reaction, thereby causing a problem of reduced strength development of the artificial aggregate.

[0056] The above mixture may contain 10 to 20 parts by weight of filler per 100 parts by weight of the above mixture powder, and the filler may be a composite material mixed with one or more selected from the group consisting of calcium carbonate, bottom ash, copper slag, or steelmaking slag, and most suitably may be made by mixing calcium carbonate and steelmaking slag in a 1:1 weight ratio.

[0057] The above calcium carbonate is recovered from industrial by-products and does not utilize a separate chemical reaction base within the mixture; rather, it is used as a commonly utilized filler to improve the watertightness and density of artificial aggregates.

[0058] In the present invention, the acrylic polymer resin comprises 30 to 60 wt% styrene, 10 to 30 wt% 2-hydroxyethyl acrylate, 10 to 30 wt% butyl acrylate, 0.5 to 5 wt% reactive emulsifier, 1 to 3 wt% sodium dodecyl sulfate, 1 to 2 wt% potassium persulfate, and 0.5 to 5 wt% vinyl silane, and the acrylic polymer resin may be characterized by being mixed with ion-exchanged water in a weight ratio of 5:5.

[0059] In addition, the mixture of the above acrylic polymer resin and ion-exchanged water can be named an acrylic polymer emulsion resin.

[0060] The above acrylic polymer emulsion resin is an acrylic copolymer modified with a silane entrained in a vinyl group, and the invention relates to an eco-friendly water-soluble acrylic composition designed to improve adhesion performance with artificial aggregates by imparting hydroxyl groups to the acrylic copolymer.

[0061] For example, the glass transition temperature of the above acrylic copolymer can be maintained from 10 to 50 degrees, suitably from 15 to 40 degrees, and may be a compound composed of the following chemical formula 2.

[0062] [Chemical Formula 2]

[0063]

[0064] The above acrylic polymer emulsion resin not only utilizes a basis for inducing curing without a separate curing agent by reacting with oxygen in the air and hydroxyl groups generated by the hydration reaction of the cement-free binder, such as carboxyl groups (-COOH) and carbon double bonds (C=C), but also has the characteristic of curing through hydrogen or covalent bonding reactions between the alkaline hydroxide hydroxyl groups (-OH) generated by the hydration reaction and the reactive groups of the vinyl silane coupling agent entrained in the polymer.

[0065] [Chemical Formula 3]

[0066]

[0067] Referring to Chemical Formula 3 above, OR is hydrogen or a C1-C4 alkyl group, and Y is a vinyl group.

[0068] In this specification, C1-C4 alkyl groups refer to straight-chain or branched hydrocarbons having 1 to 4 carbon atoms, and include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, etc.

[0069] As used in this specification, C2-C4 alkenyl groups refer to straight-chain or branched unsaturated hydrocarbons having 2 to 4 carbon atoms and having one or more carbon-carbon double bonds, and include, but are not limited to, vinyl, propenyl, butenyl, etc.

[0070] One or more hydrogen atoms of the above C1-C10 alkyl group, aryl group, C1-C4 alkyl group and C2-C4 alkenyl group may be substituted with a C1-C5 alkyl group, C2-C6 alkenyl group, C2-C6 alkynyl group, C3-C10 cycloalkyl group, C3-C10 heterocycloalkyl group, C3-C10 heterocycloalkyloxy group, C1-C5 haloalkyl group, C1-C5 alkoxy group, C1-C5 thioalkoxy group, aryl group, acyl group, hydroxyl, thio, halogen, amino, alkoxycarbonyl, carboxyl, carbamoyl, cyano, nitro, etc.

[0071] In addition, the acrylic polymer emulsion resin used in the present invention is intended to reduce the water absorption rate of artificial aggregates and improve strength through a polymer network structure during the manufacturing process of inorganic artificial aggregates. Specifically, it is intended to reduce the water absorption rate and improve the strength of artificial aggregates by utilizing the characteristics of the acrylic resin, such as drying performance, moisture resistance, high adhesion, and bonding properties. The application temperature range of the resin is 10 to 120°C, the polymerization process of the resin is non-volatile, no foaming occurs during the reaction, and it has very low shrinkage characteristics during curing.

[0072] The acrylic monomer included in the above acrylic copolymer may be used by including one or more selected from the group consisting of acrylic acid, methacrylic acid, styrene, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, glycidylmethacrylate, vinylsilane methyl methacrylate, isobutyl acrylate, and derivatives thereof, and suitably may include acrylic acid, styrene, 2-hydroxyethyl methacrylate, and vinylsilane, but is not limited thereto.

[0073] The above styrene may be included in an amount of 30 to 60 weight percent with respect to 100 weight percent of the above acrylic polymer resin.

[0074] For example, if included in an amount of less than 30 weight%, problems such as reduced strength and drying performance may occur, and if included in an amount exceeding 60 weight%, problems such as cracking may occur due to a decrease in tensile strength.

[0075] The above 2-hydroxyethyl acrylate may be included in an amount of 10 to 30 weight percent based on 100 weight percent of the acrylic polymer resin.

[0076] For example, if included in an amount of less than 10% by weight, problems such as a decrease in tensile strength may occur, and if included in an amount exceeding 30% by weight, problems such as a decrease in the developed strength due to a decrease in the glass transition temperature may occur.

[0077] The above emulsifier may contain one or more selected from the group consisting of nonionic emulsifiers and anionic emulsifiers, may include polyoxyethylene stearyl ether or sodium dodecyl sulfate, and suitably may include a reactive emulsifier.

[0078] The above emulsifier may be included in an amount of 0.5 to 5 weight percent based on 100 weight percent of the acrylic polymer resin.

[0079] For example, if included in an amount of less than 0.5 weight%, problems may arise such as difficulty in water solubilization, and if included in an amount exceeding 5 weight%, problems may arise such as a decrease in water resistance.

[0080] The above vinylsilane contains both a reactive group (-Y) that reacts with organic materials and an alkoxy group (-OR) that reacts with inorganic materials within the compound, and forms a silanol group by reacting with water and hydrolysis, and exhibits adhesion strength through hydrogen bonding or chemical bonding between the hydroxyl group (-OH) present in the vinylsilane group and the hydroxyl group on the surface of the organic or inorganic material as shown in Reaction Scheme 1 below.

[0081] [Reaction Equation 1]

[0082]

[0083] The vinyl silane may be included in an amount of 0.5 to 5 weight percent relative to 100 weight percent of the acrylic copolymer. For example, if it is included in an amount less than 0.5 weight percent, problems such as reduced adhesion and heat resistance may occur, and if it is included in an amount exceeding 5 weight percent, problems such as reduced flexibility may occur.

[0084] In the present invention, with respect to 100 parts by weight of the mixed powder, the water may be included in an amount of 30 to 35 parts by weight.

[0085] In the present invention, with respect to 100 parts by weight of water, 10 to 15 parts by weight of sodium hydroxide, 1 to 3 parts by weight of sodium silicate, and 1 to 3 parts by weight of the acrylic polymer resin may be included.

[0086] Specifically, for the purpose of alkali stimulation to improve base quality and the reactivity of cement-free binders, sodium hydroxide (4.5% NaOH molar ratio) or sodium silicate (water glass, Na2SiO3) may be prepared as a stock solution of 1 to 5 mol / liter and diluted to 10 to 20% by weight relative to the total weight of water.

[0087] The artificial aggregate according to the composition and manufacturing method of the present invention is characterized by enhancing the adhesion performance of the artificial aggregate through the excellent compatibility between the hydroxyl groups of the acrylic copolymer and the vinylsilane. Accordingly, the vinylsilane can form organic / inorganic bonds by combining with inorganic materials and organic / organic bonds by combining with organic materials, thereby enhancing adhesion.

[0088] As described above, the chemical structure shown in Fig. 1 is formed by the bonding between the hydrate end of the mixed powder, the artificial aggregate interface, the vinyl silane coupling agent end, and the polymer.

[0089] Referring to Fig. 1, a silanol group is formed through a hydrolysis reaction with water as in the organic-inorganic chemical reaction structural formula, and adhesion strength on the surface of the mixed powder binder is expressed as an organic-inorganic reaction (-Si-O-) due to dehydration polymerization, hydrogen bonding, or covalent bonding between the hydroxyl group (-OH) present in the silanol group and the hydroxyl group on the surface of the attachment target, which is an organic or inorganic material.

[0090] In addition, as shown in the structural formula above, in the case of an organic-organic reaction, a bond is formed between the mixed powder and the acrylic polymer emulsion resin by the silanol reactive group through a covalent bond (-Si-C-) between the hydroxyl group (-OH) present in the silanol group and the carbon atom of the organic polymer.

[0091] According to another embodiment of the present invention, the invention relates to a method for manufacturing artificial aggregate comprising: a dry mixing step of a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; a wet mixing step of introducing a liquid comprising an acrylic polymer resin and water into the mixed powder; a granulation step of introducing the product of the wet mixing step into a cylindrical granulator to form a nucleus and a shell of artificial aggregate; an accelerated carbonation step of introducing the molded artificial aggregate into a curing machine after producing the nucleus and shell of artificial aggregate through the granulation step, and then adding carbon dioxide; and a drying and curing reaction step of 60 to 80°C for 6 to 8 hours.

[0092] The above dry mixing step involves initiating a primary cement-free binder by using a dry mixing method with a mixed powder comprising 25-55% by weight of blast furnace slag; 15-35% by weight of fly ash; 3-10% by weight of sodium carbonate; 10-20% by weight of calcium hydroxide; and 0.3-0.5% by weight of a setting retarder, and then initiating a final cement-free binder, i.e., a mixed powder that has undergone the dry mixing step, by including 10-20% by weight of a filler comprising calcium carbonate and steelmaking slag in 80-90% by weight of the primary cement-free binder.

[0093] Next, the wet mixing step involves performing a wet mixing step by including 30 to 35 parts by weight of water with respect to 100 parts by weight of the final cement-free binder (mixed powder obtained by performing the dry mixing step). At this time, by adding 10 to 15 parts by weight of sodium hydroxide, 1 to 3 parts by weight of sodium silicate, or 1 to 3 parts by weight of the acrylic polymer resin with respect to 100 parts by weight of the water used, the alkali stimulation and wet mixing step are carried out simultaneously to produce a mixture for granulating artificial aggregate.

[0094] The sodium carbonate (Na2CO3) included in the dry mixing stage, when the wet mixing stage is performed, causes an alkaline stimulation reaction of the slag, dissociating sodium, carbonate, and calcium ions, initiating a reaction with hydroxides during the artificial aggregate granulation process, and generating sodium hydroxide (NaOH), calcium carbonate (CaCO3), and water (H2O). The sodium hydroxide generated at this time promotes the alkaline aggregate reaction, and the calcium carbonate produced by the reaction with slaked lime (Ca(OH)2) within the hydroxides contributes to strength enhancement, utilizing this basis. In this case, to prevent excessive neutralization, the present invention is characterized by adding an aqueous sodium hydroxide solution during the wet mixing process to further generate chlorides.

[0095] In other words, it is used to induce strength in artificial aggregates through carbonates or silicates generated by inducing hydrate formation and aggregate-alkali reactions on the surface of the mixed powder by introducing a solution of sodium hydroxide and sodium silicate to induce an alkaline stimulation reaction and a one-component acrylic polymer emulsion resin to induce a polymer reaction into a mixture of anti-absorbent binders (mixed powder) prepared in a dry mixing step, which is a wet mixing step, and introducing a solution of sodium hydroxide and sodium silicate to induce an alkaline stimulation reaction, and to form a polymer network structure during the curing process through hydrogen bonding with the organic polymer at the interface between the silane binder (silane coupling agent) entrained at the end of the introduced polymer resin and the inorganic material.

[0096] Next, the granulation step comprises introducing the mixture for granulating artificial aggregate, which is the product of the wet mixing step, into a cylindrical granulator to form the core and outer shell of the artificial aggregate, and producing fine aggregate of 2 to 5 mm in a first cylindrical pan with an inclination of 30 to 35 and a rotational speed of 30 to 35 rpm; or producing coarse aggregate of 10 mm or more in a second cylindrical pan with an inclination of 40 to 45° and a rotational speed of 30 to 35 rpm.

[0097] The artificial aggregate formed through the above granulation step is introduced into a curing machine with controlled pressure, temperature, and humidity, and as carbon dioxide with controlled concentration is applied, an accelerated carbonation reaction can be induced in the outer layer through a reaction with calcium hydroxide (slaked lime), calcium oxide (quicklime), magnesium hydroxide, etc. present in the outer layer of the artificial aggregate.

[0098] That is, after being introduced into the curing machine, an accelerated carbonation step is performed by applying carbon dioxide.

[0099] In the present invention, the accelerated carbonation step is performed for 6 to 8 hours in an environment with a carbon dioxide concentration of 15 to 20%, a temperature of 40 to 80°C, a pressure of 1 to 2 atmospheres, and a relative humidity of 40 to 60%, thereby carrying out an accelerated carbonation reaction to any depth from the outer shell of the artificial aggregate to form an aggregate with a dense outer shell structure.

[0100] Specifically, calcium carbonate, which is produced by the reaction of calcium hydroxide (Ca(OH)2) and CaO present in large quantities in the outer shell of granulated artificial aggregate, is utilized to improve the strength and density of the aggregate.

[0101] Furthermore, accelerated carbonation manifests as a reaction effect through the formation of a white outer layer of calcium carbonate on the aggregate surface. Once the accelerated carbonation reaction begins, the aggregate temperature rises for a certain period and then converges to a constant temperature upon the completion of the reaction. At this time, an additional hydration environment is created as the curing temperature rises, and there is the advantage that the hydration reaction of blast furnace slag fine powder is also promoted during the curing process.

[0102] Chemical formula 4 below represents the reaction between quicklime and carbon dioxide, and chemical formula 5 represents the reaction between calcium hydroxide and carbon dioxide.

[0103] [Chemical Formula 4]

[0104] CaO + CO2 --> CaCO3

[0105] [Chemical Formula 5]

[0106] Ca(OH)2 + CO2 → CaCO3 + H2O

[0107] Next, the accelerated carbonation step is characterized by including a process for manufacturing the final inorganic cured artificial aggregate in parallel with a step of drying in air after curing for 6 to 8 hours at a humidity of 40 to 60% and a temperature of 60 to 80 degrees, which are curing conditions for the artificial aggregate.

[0108] The artificial aggregate produced according to the present invention can be obtained as shown in FIG. 2 and has excellent durability capable of developing a crushing strength of 10 MPa or more, which is typically at the level of soft rock, without the calcination process of 1,000°C used in conventional artificial aggregate manufacturing technology, and can be used to replace part or all of the natural aggregate in construction members of buildings or civil engineering structures.

[0109] In addition, when high-density artificial aggregate similar in specific gravity to natural aggregate manufactured according to the present invention is used in an inorganic cement concrete mixture for construction or road use, coarse aggregate or fine aggregate can be selectively substituted according to the cement concrete mix design.

[0110] The fine aggregate formed into granules in the cylindrical pan of the present invention refers to a diameter of 2 to 5 mm, and the coarse aggregate refers to a diameter of 10 mm or more. Accordingly, weight substitution is performed according to the aggregate mix design results of the object of application, and is characterized by substituting 10 to 50 weight percent of natural aggregate.

[0111] Artificial aggregate produced according to the present invention can be used by replacing a portion of sand, crushed stone, gravel, etc. included in an asphalt mixture in a volume ratio or weight ratio. When using high-density artificial aggregate with a specific gravity similar to that of natural aggregate, it is preferable to selectively replace aggregate with 4.75 mm (No. 4) sieve or 10 mm (No. 2) sieve in a weight ratio.

[0112] The asphalt binder used in the above asphalt mixture may be straight asphalt, blown asphalt, etc., but is not limited thereto. At this time, the asphalt binder may be 1 to 30 weight percent of the total weight of the asphalt mixture, and suitably 3 to 20 weight percent.

[0113] In addition, during the process of manufacturing an asphalt mixture, asphalt reinforcing material, aggregate, and asphalt binder are mixed in the above weight ratio, and it is suitable to heat the mixture to a temperature of 120 to 170°C during this process. The artificial aggregate manufactured according to the present invention has the effect of maintaining its original shape at the above mixing temperature.

[0115] The present invention will be described in more detail below through examples. These examples are intended solely to explain the present invention more specifically, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by these examples according to the gist of the invention.

[0117] Examples

[0118] Preparation Example 1.

[0119] The acrylic polymer emulsion resin used in the embodiments of the present invention was prepared as follows.

[0120] First, 10g of potassium persulfate, 1500g of ion-exchanged water, and 1g of SR-10 (ADEKA, reactive emulsifier) ​​were added to a 4-neck round-bottom flask (1L) equipped with a thermometer, condenser, and stirrer, and then 80 The temperature rises until.

[0121] Next, 1000g of styrene, 50g of acrylic acid, 200g of 2-hydroxyethyl acrylate, 500g of butyl acrylate, 20g of vinylsilane, 19g of SR-, 20g of sodium dodecyl sulfate, and 760g of ion-exchanged water are added to dropping panel 1 and stirred to prepare a pre-emulsion.

[0122] Next, prepare Dropping Panel 2 by mixing 20g of potassium persulfate and 40g of ion-exchanged water. Dropping Panel 1 and Dropping Panel 2 are uniformly introduced at 90℃ for 5 hours.

[0123] Next, once the dropping is complete, the reaction is maintained for 2 hours, then 1 g of an aqueous solution of potassium persulfate, which is a polymerization initiator, is added and the reaction is carried out for 1 hour, then cooled to 60°C and neutralized with triethanolamine or ammonia.

[0124] In the implementation section, 1-5% of water-soluble paraffin wax is added based on solid content to compare hygroscopicity.

[0125] The solid content of the acrylic polymer emulsion resin produced at this time is 45%, the viscosity is 250 cps, the pH is 8.4, the non-volatile content is 44.5%, and the glass transition temperature is 25 degrees.

[0127] Preparation Example 2.

[0128] The artificial aggregate used in the embodiments of the present invention was prepared from a mixture for granulating artificial aggregate prepared with the composition ratios shown in Table 1 below.

[0129] division Blast furnace slag Fly ash sodium carbonate calcium hydroxide Setting retardant Primary non-cemented binder (weight%) 54.5 20 10 15 0.5 division Primary cement-free binder Mixed filler - - - Final cement binder (weight%) 80 20 - - - division water Sodium hydroxide Sodium silicate acrylic polymer free resin - Liquid (parts by weight) 100 parts by weight 15 parts by weight 3 parts by weight 3 parts by weight -

[0130] Referring to Table 1 above, a mixed powder comprising 54.5 wt% blast furnace slag, 20 wt% fly ash, 10 wt% sodium carbonate, 15 wt% calcium hydroxide, and 0.5 wt% setting retarder was prepared as a primary cement-free binder through a dry mixing method. Then, a final cement-free binder, i.e., a mixed powder that underwent a dry mixing step, was prepared by including 80 wt% of the primary cement-free binder and 20 wt% of a mixed filler (10 wt% calcium carbonate and 10 wt% steel slag). Next, a mixture for artificial aggregate granulation was prepared by adding 35 wt% of a liquid, prepared by including 15 wt% sodium hydroxide at a molar ratio of 4.5% relative to 100 wt% water, 3 wt% sodium silicate, and 3 wt% acrylic polymer emulsion resin according to Preparation Example 1, to the mixed powder and performing a wet mixing step.

[0131] Referring to Fig. 2, the results of a heavy metal leaching test for the mixture for artificial aggregate granulation prepared according to Example 2 are shown. It can be confirmed that the results satisfy all environmental standards.

[0132] Next, the mixture for artificial aggregate granulation is manufactured into artificial aggregate through the stirring and granulation device for artificial aggregate shown in Fig. 3, and the artificial aggregate manufactured accordingly is shown in Figs. 4 and 5.

[0134] Experimental Example

[0135] division Unit material quantity (kg / m³) Substitution rate (%) water cement fine aggregate Coarse aggregate artificial aggregate Comparative example 3.96 9 19.78 18.47 0 0 Example 1 3.96 9 19.78 16.62 1.85 10 Example 2 3.96 9 19.78 15.70 2.77 15 Example 3 3.96 9 19.78 12.93 5.54 30

[0136] A general cement concrete mixture was set as a comparative example, and an artificial aggregate substituted concrete in which artificial aggregate produced according to the artificial aggregate manufacturing method of the present invention was substituted was set as an example, and the composition of the concrete mixtures included in the comparative example and the example is shown in Table 2 above.

[0137] Specifically, the comparative example is a typical weight% composition of a commonly used cement concrete mixture, and

[0138] The above substitution rate refers to the ratio in which a portion of the coarse aggregate is replaced with artificial aggregate prepared according to Manufacturing Example 2, compared to the comparative example.

[0139] The following experiments were conducted on crushing compressive strength according to the replacement rate of artificial aggregates, measurement of concrete mixture specifications, and relative strength improvement effects, and the results are shown in Tables 3 to 5 below.

[0141] 1. Crushing compressive strength according to artificial aggregate replacement rate

[0142] The crushing compressive strength was measured by the Korea Institute of Quality Technology (KIQT) in accordance with the KS L 5105 (mortar compressive strength) test method, and the target value was set to 10 MPa, which is the compressive strength of general soft rock (limestone). In addition, the age was 7 days.

[0143] division Test results Comparative example 17.0 MPa Example 1 16.4 MPa Example 2 17.7 MPa Example 3 17.4 MPa

[0144] Referring to Table 3 above, it can be seen that all of Examples 1 to 3 exhibit a crushing compressive strength superior to that of soft rock, which is 10 MPa, and in the case of Examples 2 and 3, it can be seen that the crushing compressive strength is even superior to that of the comparative example.

[0145] In addition, FIG. 6 is a standard test specimen according to Examples 1 to 3 in which a compressive strength test was conducted.

[0146] Accordingly, it can be seen that the artificial aggregate according to the present invention has a crushing compressive strength that allows it to be used as a substitute for natural aggregate.

[0148] 2. Measurement of concrete mixtures according to specifications

[0149] The specifications for the concrete mixture were measured for slump, air content, compressive strength and flexural strength on day 7.

[0150] Specifically, slump was measured according to the KS F 2402:2017 test method, air content according to the KS F 2421:2016 test method, compressive strength on day 7 according to the KS F 2405:2017 test method, and flexural strength on day 7 according to the KS F 2408:2016 measurement method, and the compressive strength and flexural strength on day 7 were recorded as the average values ​​of the results of three measurements each.

[0151] division slump Air volume Compressive strength (7 days) Flexural strength (7 days) Comparative example 185mm 2.5% 39.0 Mpa(37.3,38.0, 41.6) 5.50 Mpa(5.44, 5.54, 5.52) Example 1 200mm 2.7% 42.2 Mpa(43.1, 42.5, 41.1) 5.53 Mpa(5.55, 5.45, 5.58) Example 2 205mm 2.8% 48.8 Mpa(50.2, 46.2, 50.0) 5.62 Mpa(5.88, 5.45, 5.54) Example 3 220mm 3.6% 43.2 Mpa(41.3, 42.8, 45.5) 5.47 Mpa(5.83, 5.84, 4.76)

[0152] Referring to Table 4 above, it can be seen that Examples 1 to 3 all satisfy the standard specifications for concrete mixtures, and that in terms of slump, air content, and compressive strength (7 days), they all showed excellent effects compared to the comparative example.

[0153] In addition, Figure 7 shows specimens tested for compressive strength and flexural strength of the comparative example and Example 1, and in the case of Example 1, it can be visually confirmed that the durability is similar to that of a conventional concrete mixture.

[0154] Accordingly, it can be seen that the artificial aggregate according to the present invention has the durability to be used as a substitute for natural aggregate.

[0156] 3. Relative Strength Improvement Effect of Artificial Aggregate Replacement Asphalt Concrete

[0157] An additional experiment was conducted to measure the relative strength improvement effect when the artificial aggregate according to the present invention is used as an asphalt concrete mixture, and the results are listed in Table 5 below.

[0158] In addition, Examples 4 to 7 contain different substitution rates for artificial aggregate, which means a ratio in which a portion of the coarse aggregate is replaced with artificial aggregate prepared according to Preparation Example 2.

[0159] Specifically, regarding the experimental method, the standard value is 0.8 MPa, and the indirect tensile strength measured three times and the average value of the measured results are listed.

[0160] division Example 4 Example 5 Example 6 Example 7 Artificial aggregate replacement rate (%) 5 10 25 50 Indirect tensile strength (MPa) 0.91 0.92 0.87 0.87 0.84 0.90 0.92 0.90 0.87 0.85 0.90 0.83 Average value (MPa) 0.90 0.87 0.88 0.86

[0161] Referring to Table 5 above, it can be confirmed that all of Examples 4 to 7 have excellent indirect tensile strength of 0.85 MPa or higher. Thus, it was confirmed that there is an effect of improving relative strength by satisfying all conventional indirect tensile standards. In addition, Figure 8 shows asphalt concrete specimens tested for indirect tensile strength for Examples 4 to 7, and it can be visually confirmed that they are similar to the durability of a conventional asphalt mixture.

[0162] Accordingly, it can be seen that the artificial aggregate according to the present invention has the durability to be used as an asphalt concrete mixture by replacing natural aggregate.

[0164] Therefore, it was found that when about 10% to 50% of the artificial aggregate manufactured according to the present invention is substituted to be used as aggregate for a cement concrete mixture for construction, workability is improved by reducing friction between aggregates during mixing, and the strength of the mixture is improved by reducing the water-cement ratio.

[0165] In addition, it was found that when about 10% to 50% was replaced to be used as aggregate for asphalt mixtures for road paving, it increased the bonding strength between aggregates and significantly improved the durability of the mixture.

[0166] In addition, the artificial aggregate composition according to the present invention allows for size adjustment of the artificial aggregate according to the size of the injection nozzle used in injection molding, enabling it to be utilized as a concept of a substitute material that adds a portion of the total volume of the mixture used, and provides the advantage of reducing the amount of aggregate used compared to the weight of the substitute aggregate during plant production.

[0167] As described above, when an artificial aggregate composition is prepared according to the present invention, comprising a mixed powder containing blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and a liquid phase containing an acrylic polymer resin and water, the crushing strength is expressed at a level equivalent to or greater than that of ordinary soft rock (limestone), and since it has a compressive strength greater than that of natural crushed stone aggregate, it can be used as a partial substitute for natural aggregate in concrete, asphalt, and concrete secondary product mixtures, thereby supplementing and improving performance compared to the use of natural aggregate.

[0169] Specific parts of the present invention have been described in detail above. It is evident to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims

Claim 1 An artificial aggregate composition comprising: a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retardant; and a liquid phase comprising an acrylic polymer resin and water, wherein the acrylic polymer resin comprises 30 to 60 wt% styrene, 10 to 30 wt% 2-hydroxyethyl acrylate, 10 to 30 wt% butyl acrylate, 0.5 to 5 wt% reactive emulsifier, 1 to 3 wt% sodium dodecyl sulfate, 1 to 2 wt% potassium persulfate, and 0.5 to 5 wt% vinyl silane, and wherein the acrylic polymer resin is mixed with ion-exchanged water in a weight ratio of 5:

5. Claim 2 The artificial aggregate composition according to claim 1, wherein the mixed powder comprises 25 to 55 weight% of blast furnace slag; 15 to 35 weight% of fly ash; 3 to 10 weight% of sodium carbonate; 10 to 20 weight% of calcium hydroxide; and 0.3 to 0.5 weight% of a setting retardant. Claim 3 An artificial aggregate composition according to claim 2, comprising 10 to 20 parts by weight of a filler mixed with calcium carbonate and steel slag in a 1:1 weight ratio, with respect to 100 parts by weight of the mixed powder. Claim 4 delete Claim 5 An artificial aggregate composition according to claim 1, wherein the water is included in an amount of 30 to 35 parts by weight per 100 parts by weight of the mixed powder. Claim 6 An artificial aggregate composition according to claim 5, comprising, with respect to 100 parts by weight of water, 10 to 15 parts by weight of sodium hydroxide, 1 to 3 parts by weight of sodium silicate, and 1 to 3 parts by weight of the acrylic polymer resin. Claim 7 A dry mixing step of a mixed powder comprising blast furnace slag, fly ash, sodium carbonate, calcium hydroxide, and a setting retarder; a wet mixing step of introducing a liquid comprising an acrylic polymer resin and water into the mixed powder; a granulation step of introducing the product of the wet mixing step into a cylindrical granulator to form the nucleus and outer shell of artificial aggregate; an accelerated carbonation step performed by introducing carbon dioxide after producing the artificial aggregate nucleus and outer shell through the granulation step and introducing the molded artificial aggregate into a curing machine. A method for manufacturing artificial aggregate comprising the step of drying and curing at 60 to 80°C for 6 to 8 hours, wherein the acrylic polymer resin comprises 30 to 60 wt% styrene, 10 to 30 wt% 2-hydroxyethyl acrylate, 10 to 30 wt% butyl acrylate, 0.5 to 5 wt% reactive emulsifier, 1 to 3 wt% sodium dodecyl sulfate, 1 to 2 wt% potassium persulfate, and 0.5 to 5 wt% vinyl silane, and wherein the acrylic polymer resin is mixed with ion-exchanged water in a weight ratio of 5:

5. Claim 8 A method for manufacturing artificial aggregate according to claim 7, wherein the granulation step comprises: a step of manufacturing fine aggregate of 2 to 5 mm in a first cylindrical pan with an inclination of 30 to 35° and a rotational speed of 30 to 35 rpm using the product of the wet mixing step; or a step of manufacturing coarse aggregate of 10 mm or more in a second cylindrical pan with an inclination of 40 to 45° and a rotational speed of 30 to 35 rpm. Claim 9 A method for manufacturing artificial aggregate according to claim 7, wherein the accelerated carbonation step is performed for 6 to 8 hours in an environment with a carbon dioxide concentration of 15 to 20%, a temperature of 40 to 80°C, a pressure of 1 to 2 atmospheres, and a relative humidity of 40 to 60%.

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