Eco-Friendly Xanthan Gum-Based Solidifying Material Composition and Method for Ground Stabilization Using the Same

Abstract

The present invention relates to a xanthan gum-based eco-friendly solidification agent composition and a ground solidification method using the same. It replaces conventionally used cement to minimize cement usage and instead uses a mixture of blast furnace slag and combined heat and power (CHP) ash. By using a modified active binder and a curing stimulant obtained through the fine grinding of industrial by-products to enhance the reactivity of the blast furnace slag and CHP ash, strength can be improved and the resource circulation effect can be enhanced by recycling waste resources. Furthermore, by utilizing xanthan gum, a naturally derived biopolymer, a sustainable solidification solution can be provided. Additionally, by using eco-friendly materials, the leaching of heavy metals such as hexavalent chromium is minimal, thereby making the solidification agent composition and the ground solidification method using the same eco-friendly.

Description

Technology Field

[0001] The present invention relates to a xanthan gum-based eco-friendly solidification agent composition and a ground solidification method using the same. It replaces conventionally used cement to minimize cement usage and instead uses a mixture of blast furnace slag and combined heat and power (CHP) ash. By using a modified active binder and a curing stimulant obtained through the fine grinding of industrial by-products to enhance the reactivity of the blast furnace slag and CHP ash, strength can be improved and the resource circulation effect can be enhanced by recycling waste resources. Furthermore, by utilizing xanthan gum, a naturally derived biopolymer, a sustainable solidification solution can be provided. Additionally, by using eco-friendly materials, the leaching of heavy metals such as hexavalent chromium is minimal, thereby making the solidification agent composition and the ground solidification method using the same eco-friendly. Background Technology

[0002] Most major urban areas in Korea were developed along rivers and coastlines, and the areas near the surface consist of loose reclaimed land and sedimentary layers. Social infrastructure facilities and small structures, such as water and sewage pipelines, gas pipes, communication conduits, power tunnels, and drainage boxes, are installed directly as foundations on these loose sandy soils near the surface. Consequently, vibrations from nearby construction equipment, groundwater leakage, and liquefaction during earthquakes can cause sinkholes, ground subsidence, and collapses, potentially resulting in severe damage.

[0003] Furthermore, large-scale construction projects are currently underway and planned domestically, including ground improvement work along the West and South coasts as well as maintenance projects for rivers, landfills, and wetlands. Along with the expansion of social infrastructure, large-scale underground excavation work is also being carried out and planned due to the need for larger structures and the development of various underground spaces. In particular, considering the country's limited land area, ground improvement and stabilization are essential for expanding national territory through coastal development and land reclamation projects.

[0004] Ground reinforcement is being carried out to prevent damage caused by such soil liquefaction and to promote coastal development.

[0005] Conventional ground reinforcement methods have mainly utilized sand drainage and sand compaction methods, but these methods were difficult to apply to soft ground with a depth of 25 m and did not easily ensure stability after construction.

[0006] Due to these problems, deep mixing treatment methods are primarily used recently to improve soft ground by adding lime or cementitious chemical stabilizers and mixing them with local clay soil using mechanical mixing devices.

[0007] This deep mixing treatment method is a type of chemical treatment that offers significant improvement effects compared to conventional physical methods, enables the early securing of high strength, and has the advantage of allowing construction regardless of whether it is on land or at sea due to low vibration and noise.

[0008] However, the solidification agents used in this deep mixing treatment method primarily consist of Portland cement or slag cement, with pozzolanic materials added in some cases. Since the clayey soil in the ground contains a large amount of organic matter, the hydration reaction of the cement is hindered by this organic matter. Specifically, the organic components within the clayey soil consist of colloidal substances that are hydrophilic and have excellent cation adsorption capabilities. Because these substances adsorb to soil particles and obstruct contact between the cement and the soil particles, there is a problem in that the ground improvement effect of the cement is reduced.

[0009] Furthermore, cement production generates large amounts of carbon dioxide (CO2), accelerating the increase in greenhouse gases and climate change; additionally, mining processes cause ecosystem destruction and lead to groundwater and soil contamination due to the generation of alkaline leaching with high pH; therefore, there is a need to develop eco-friendly reinforcing materials that can replace cement.

[0010] Examples of technologies proposed regarding conventional ground reinforcement methods are as follows.

[0011] First, Korean registered patent No. 10-1154839 proposes a solidification agent composition for soft ground in which a solid acid catalyst, such as zeolite, silica, or alumina, is mixed with blast furnace slag powder, cement powder, and gypsum powder. The patent explains that by including a solid acid catalyst in the solidification agent composition, fluidity is improved and extrusion strength is enhanced to ensure workability and reduce the generation of discharge slurry, while the amount of cement is minimized to minimize the leaching of carbon dioxide and hexavalent chromium. Furthermore, excellent strength can be achieved by adsorbing organic acids that inhibit the hydration reaction of cement and forming a dense structure through the generation of ettringite.

[0012] In addition, Korean registered patent No. 10-0727654 proposes a solidification agent composed of a mixture of fly ash, muscovite, anhydrous gypsum, and quicklime with cement, and explains that this solidification agent exhibits superior solidification effects compared to existing Portland cement-based solidification agents when applied to marine clay, organic matter-containing soil, waste-containing soil, and soft ground with high moisture content.

[0013] In addition, Korean registered patent No. 10-0719628 proposes a soil solidification agent in which a solidification agent raw material composed of calcium chloride, lignin sulfonate, tripolyate, ferrous sulfate, stearate, sodium hydroxide, magnesium chloride, and calcium oxide is mixed with cement. This technology explains that a solidification method using a soil solidification agent containing stearate, in particular among the above compositions, enables rapid solidification treatment, can exhibit excellent compressive strength, and allows for safe ground solidification without settlement.

[0014] In addition, Korean registered patent No. 10-0550340 discloses a solidification composition comprising fly ash, a reactive agent (iron), a solidification agent, and cement, and a technology for solidifying sludge using the same. This technology explains that the solidification agent includes sodium chloride, potassium chloride, magnesium chloride, calcium chloride, aluminum chloride, ferric chloride, ammonium chloride, carbon, citric acid, a nonionic surfactant, and sodium sulfate, thereby increasing the reactivity of cement and fly ash by removing contaminants within the sludge through an ion exchange reaction.

[0015] Furthermore, Korean Published Patent No. 10-2013-0109688 discloses a solidification composition obtained by mixing local soil and cement with a solidification accelerator, and discloses a composition comprising natural magnesium hydroxide, magnesium chloride, calcium chloride, potassium chloride, sodium chloride, sodium hydroxide, potassium hydroxide, active magnesium hydroxide, and hydroxytricarboxylic acid as the solidification accelerator. This technology explains that by using a solidification accelerator having the above composition, the curing time can be shortened, compressive strength and permeability coefficients can be controlled, and thermal resistance, such as protection against freezing in winter, as well as durability and crack resistance, can be improved.

[0016] In addition, conventional ground solidification agents have been proposed, including methods based on cement that additionally include various pozzolanic materials (Republic of Korea Registered Patents No. 10-0913268, No. 10-1299163, No. 10-1148916, No. 10-0521848, No. 10-0145637, No. 10-0648461, No. 10-0876222, No. 10-242569, No. 10-1299164, etc.) and methods that additionally include accelerators such as metal salts (Republic of Korea Registered Patent No. 10-0857916, etc.).

[0017] Existing ground reinforcement methods are based on cement, but cement contains hexavalent chromium among its components. Therefore, when ground is improved using this method, there is a problem in that hexavalent chromium may leach into the soil at concentrations exceeding environmental soil standards. To solve this, it is necessary to minimize the amount of cement used in materials for ground reinforcement and solidification.

[0018] In addition, there was a need to develop a technology that utilizes biopolymers to bind soil particles and prevent erosion while possessing excellent adhesiveness, thickening properties, and stability. The problem to be solved

[0019] The present invention is derived in consideration of the above-mentioned situation and aims to provide a solidification agent composition for ground reinforcement that minimizes cement usage by replacing conventionally used cement, and instead uses a mixture of blast furnace slag and combined heat and power (CHP) ash. By using a modified active binder obtained through the fine grinding of industrial by-products to enhance the reactivity of the blast furnace slag and CHP ash, strength can be improved and the resource circulation effect can be enhanced by recycling waste resources. Furthermore, by utilizing xanthan gum, a naturally derived biopolymer, a sustainable solidification solution can be provided. Additionally, by using eco-friendly materials, the leaching of heavy metals such as hexavalent chromium is low, and the composition possesses excellent characteristics in terms of liquefaction and seismic reinforcement effects.

[0020] In addition, the present invention aims to provide an eco-friendly solidification agent composition that can improve physical properties and simultaneously exhibit an eco-friendly function through resource recycling by minimizing the use of cement as a solidification agent used for ground reinforcement and additionally using pozzolanic materials such as blast furnace slag and combined heat and power plant ash, which are industrial by-products, but using circulating fluidized bed boiler ash and wet gypsum generated in the desulfurization process of a power plant to stimulate the surface of the blast furnace slag and combined heat and power plant ash to improve reactivity, thereby enhancing strength through improved reactivity of the blast furnace slag and combined heat and power plant ash.

[0021] In addition, the present invention aims to provide technology regarding a ground solidification agent and a ground stabilization method that protects the environment by utilizing xanthan gum, a naturally derived biopolymer, in a ground solidification agent, and can stably bind soil particles and prevent erosion based on excellent adhesiveness, thickening properties, and stability, and also has excellent physical properties such as compressive strength and flexural strength, as well as chemical resistance and corrosion resistance, thereby maximizing the ground solidification effect so that the ground can be stably supported even in the event of natural disasters such as heavy rain, and can improve economic efficiency by shortening the overall construction period.

[0022] In addition, the present invention provides an economical technology that offers superior initial strength and long-term stability compared to conventional cement-based solidification agents, thereby ensuring stability in soft ground improvement, foundations for port structures, embankments on land, underground continuous walls, earth retaining foundations, and excavation work, and providing a solution for establishing settlement countermeasures for structures. Furthermore, since it does not contain harmful heavy metal components, it reduces waste disposal costs for excavated soil and slime and allows for recycling as waste soil at construction sites. means of solving the problem

[0023] To achieve the above objective, one embodiment of the present invention is

[0024] The present invention provides an eco-friendly ground solidification agent composition comprising 10 to 40 parts by weight of a cementitious binder, 10 to 40 parts by weight of blast furnace slag, 10 to 30 parts by weight of desulfurization gypsum, 1 to 10 parts by weight of combined heat and power plant ash, 1 to 15 parts by weight of calcium carbonate, 3 to 10 parts by weight of silica fume surface-modified with nanosilica, 1 to 10 parts by weight of xanthan gum, 1 to 5 parts by weight of redispersible polymer powder, 0.2 to 1.2 parts by weight of shrinkage reducing agent, 0.1 to 10 parts by weight of fine quartz powder, 0.2 to 1.2 parts by weight of high-performance water reducer, 0.02 to 0.2 parts by weight of thickener, 0.1 to 1.0 parts by weight of fiber, 0.01 to 0.5 parts by weight of CSA expansion agent, 0.01 to 1.0 parts by weight of lithium carbonate, and 20 to 40 parts by weight of a modified active binder.

[0025] In one embodiment of the present invention,

[0026] The above cementitious binder is characterized by using a low-cemente binder, and the low-cemente binder

[0027] The invention is characterized by comprising 100 parts by weight of a powder component obtained by a method comprising: preparing industrial by-products including incineration ash, waste gypsum, waste lime, and combustion residue generated from an incineration facility; preparing waste glass fibers generated during the glass fiber manufacturing process; mixing the prepared industrial by-products and waste glass fibers in a ratio of 100:1 to 100 parts by weight each; feeding the mixed components into a grinding device and grinding them to collect a powder mixture; and mixing 50 to 100 parts by weight of Portland cement based on 100 parts by weight of the obtained powder mixture, and a mixture of calcium aluminate, calcium sulfoaluminate, magnesium aluminate, and magnesium sulfoaluminate in a weight ratio of 20 to 50 parts by weight.

[0028] In addition, in one embodiment of the present invention,

[0029] The above-mentioned modified active binder is produced by forming a mixed raw material by mixing circulating fluidized bed boiler ash and wet gypsum generated in the desulfurization process of a power plant with silica fume, fly ash, and a grinding aid, and then grinding this material in a fine grinding equipment to obtain a fineness of 6,000 to 9,000 cm² 2 It is characterized by being / g.

[0030] In addition, in one embodiment of the present invention, the eco-friendly solidifying agent composition further comprises 0.05 to 5.0 parts by weight of a cross-linked acrylic resin based on 10 to 40 parts by weight of a cementitious binder, wherein the cross-linked acrylic resin is obtained by ether bonding using 2-HEMA (Hydroxyethyl Methacrylate) or GMA (Glycidyl Methacrylate) with hexamethoxymethyl melamine as a crosslinking agent, and is characterized by using a resin having a weight-average molecular weight in the range of 5,000 to 100,000.

[0031] In addition, to achieve the above objectives, another embodiment of the present invention is

[0032] The present invention provides a ground reinforcement method characterized by reinforcing the ground using the above-described eco-friendly ground solidification agent composition according to the present invention. Effects of the invention

[0033] The ground solidification composition according to the present invention replaces conventionally used cement for reinforcing soft ground, thereby minimizing the amount of cement used. Instead, it uses a mixture of blast furnace slag powder and combined heat and power (CHP) ash, and by using a modified active binder obtained through the fine grinding of industrial by-products to enhance the reactivity of the blast furnace slag powder and CHP ash, it can increase strength and enhance resource circulation effects by recycling waste resources. At the same time, by reducing the amount of cement used, it has an eco-friendly effect with minimal leaching of heavy metals such as hexavalent chromium.

[0034] In addition, by using a low-cement binder that minimizes the amount of cement in the solidification composition for ground reinforcement, the environment is protected, and physical properties such as compressive strength and flexural strength, as well as chemical and corrosion resistance, are excellent, thereby maximizing the ground reinforcement effect so that the ground can be stably supported even in the event of natural disasters such as heavy rain, and the overall construction period can be shortened, thereby improving economic efficiency.

[0035] In addition, compared to existing cementitious materials, it has superior initial strength and long-term stability, which can secure stability for soft ground improvement, foundations for port structures, onshore embankments, underground continuous walls, earth retaining foundations, and excavation work, and can provide a solution for establishing settlement countermeasures for structures. Furthermore, since it does not contain harmful heavy metal components, it reduces waste disposal costs for excavated soil and slime, and can be recycled as waste soil at construction sites, thus offering excellent economic benefits.

[0036] Furthermore, the ground solidification composition according to the present invention utilizes xanthan gum, a naturally derived biopolymer, to strengthen the bonding between high-moisture clay components and cement components and promote solidification, thereby enabling rapid solidification treatment. Additionally, it exhibits excellent compressive strength results sufficient to satisfy the compressive strength criteria of the Standard General Specification. Therefore, using the ground solidification composition according to the present invention facilitates the construction and use of structures on soft ground, enables the smooth progress of various ground construction projects in areas where ground treatment and aggregate supply are difficult, and has the effect of blocking leachate generated from various industrial wastes and landfills from infiltrating into the soil and groundwater.

[0037] In addition, the ground solidification composition used in the present invention has excellent bonding strength with the original ground, so material separation does not occur, and it has excellent durability and crack prevention effects, as well as excellent freezing prevention effects during severe cold weather. Compared to general cement-based materials currently in use, it has excellent environmental and economic benefits, and has excellent liquefaction and seismic reinforcement effects. Specific details for implementing the invention

[0038] The following describes specific details for implementing the present invention.

[0039] First, the environmentally friendly ground solidification agent composition according to the present invention will be described in detail.

[0040] The eco-friendly ground solidification agent composition according to the present invention is composed of a cementitious binder, blast furnace slag, desulfurization gypsum, combined heat and power plant ash, calcium carbonate, silica fume surface-modified with nano silica, xanthan gum, etc., as a solidification agent for preventing ground subsidence and reinforcing the liquid phase.

[0041] More specifically, the eco-friendly ground solidification agent composition according to the present invention comprises 10 to 40 parts by weight of a cementitious binder, 10 to 40 parts by weight of blast furnace slag, 10 to 30 parts by weight of desulfurization gypsum, 1 to 10 parts by weight of combined heat and power plant ash, 1 to 15 parts by weight of calcium carbonate, 3 to 10 parts by weight of silica fume surface-modified with nanosilica, 1 to 10 parts by weight of xanthan gum, 1 to 5 parts by weight of redispersible polymer powder, 0.2 to 1.2 parts by weight of shrinkage reducing agent, 0.1 to 10 parts by weight of fine quartz powder, 0.2 to 1.2 parts by weight of high-performance water reducer, 0.02 to 0.2 parts by weight of thickener, 0.1 to 1.0 parts by weight of fiber, 0.01 to 0.5 parts by weight of CSA expansion agent, 0.01 to 1.0 parts by weight of lithium carbonate, and 20 to 40 parts by weight of a modified active binder.

[0042] In the present invention, well-known general cements such as ordinary Portland cement (OPC), slag cement, alumina cement, and rapid-hardening cement may be used as the cement-based binder, but a low-cement-based binder with high eco-friendliness may be used alone or in combination.

[0043] In the present invention, the low-cement-based binder is characterized by minimizing the amount of cement used and using industrial by-products processed using a special processing method and mixed with cement.

[0044] In the present invention, the low-cement-based binder is characterized by minimizing the amount of cement used and using industrial by-products generated from incineration facilities to produce a powder using a special processing method and mixing it with cement.

[0045] Specifically, the low-cement-based binder is characterized by being composed of 100 parts by weight of a powder component obtained by a method of preparing industrial by-products including incineration ash, waste gypsum, waste lime, and combustion residue generated from an incineration facility, and waste glass fibers generated during the glass fiber manufacturing process, mixing the prepared industrial by-products and waste glass fibers in a ratio of 100:1 to 100 parts by weight each, feeding the mixed components into a grinding device and grinding them to collect a powder mixture, and then mixing 50 to 100 parts by weight of Portland cement based on 100 parts by weight of the obtained powder mixture, and a mixture of calcium aluminate, calcium sulfoaluminate, magnesium aluminate, and magnesium sulfoaluminate in a weight ratio of 20 to 50.

[0046] In the present invention, the incineration ash generated in the incineration facility refers to fine incineration ash obtained by separating the incineration ash or incineration ash generated after incinerating solid refuse fuel (SRF) or wood chips used in a combined heat and power plant, with a diameter of less than 0.6 mm using a sieve separator, and the combustion residue refers to other residues.

[0047] The above combined heat and power plant may include all types of power plants that use SRF or wood chips as fuel, and, for example, include small power plants.

[0048] Since the collected incineration ash above has no latent hydraulic properties, it is conventionally sieved to use powder of a size smaller than a certain size as a raw material.

[0049] In the present invention, the waste glass fiber refers to Recycled Glass Fiber (RGF) generated by glass fiber manufacturing companies. Since the RGF is in the form of fibers, clumping occurs between the fibers, making mixing difficult.

[0050] To solve this problem, the material is finely ground using a grinding facility (fine grinding equipment) and then mixed with other ingredients.

[0051] When the above RGF is first crushed and then mixed with industrial by-products including incineration ash, waste gypsum, waste lime, and combustion residue generated from an incineration facility, some mixing may occur compared to before crushing, but overall, fiber clumping may continue to occur. Therefore, after mixing the industrial by-products and the crushed RGF, the mixture is fed back into the crushing equipment to perform crushing.

[0052] In the present invention, the crushing equipment is characterized as a dry crushing type equipment that does not use water or liquid, and a mechanical crushing type equipment in which a rotating device collides with an object to crush it.

[0053] For such grinding equipment, rotary mills, hammer mills, fine impact mills, extruder mills, pin mills, ball mills, or rod mills may be used, and the choice can be made considering durability, fine grinding efficiency, and factory conditions.

[0054] In this way, the above-mentioned mixed components are fed into a grinding device and ground to collect a powder mixture, and then a powder component is obtained by mixing 50 to 100 parts by weight of Portland cement based on 100 parts by weight of the obtained powder mixture.

[0055] Subsequently, the low-cementity powder used in the present invention can be obtained by mixing 100 parts by weight of the powder component obtained above with a mixture of calcium aluminate, calcium sulfoaluminate, magnesium aluminate, and magnesium sulfoaluminate in a weight ratio of 20 to 50.

[0056] In the present invention, the calcium aluminate, calcium sulfoaluminate (CSA), magnesium aluminate, and magnesium sulfoaluminate are materials with a relatively high alumina content compared to ordinary Portland cement, and have excellent chemical resistance and the advantage of being usable in an acidic atmosphere. As a type of rapid-strength cement with a short hardening time, they can be used in an appropriate ratio with ordinary Portland cement.

[0057] In the present invention, it is preferable that the cementitious binder be included in a range of 10 to 40 parts by weight of the total solidifying agent composition. If the cementitious binder is less than 10 parts by weight, the strength development is insufficient, and if it exceeds 40 parts by weight, it is difficult to achieve the effect of the present invention aimed at reducing heavy metal leaching, so it is preferable to maintain the above range.

[0058] In the present invention, the blast furnace slag is a latent hydraulic admixture obtained by finely grinding rapidly cooled slag byproduct from a steel mill, and it serves to improve workability during casting by providing viscosity and fluidity to the solidification agent composition.

[0059] In the present invention, the blast furnace slag may be in an amorphous state and have a basicity of 1.6 to 2.0. Additionally, the blast furnace slag may be ground using a grinding device such as a ball mill, roller mill, or vibratory mill, with a fineness of 3,000 to 6,000 cm⁻¹.2 It is preferable to use one with a weight of / g. In the present invention, it is preferable that the blast furnace slag be included in the solidification agent composition in a range of 10 to 40 parts by weight.

[0060] In the present invention, the desulfurization gypsum is an artificial gypsum produced in the Flue Gas Desulfurization (FGD) process of thermal power plants or industrial facilities, and is a byproduct generated after using limestone slurry to remove sulfur oxides (SOx) generated in power plants that mainly use coal as fuel. The desulfurization gypsum plays a role in preventing the initial setting of cementitious binders and providing an appropriate setting time, which is mainly due to the role of calcium sulfate (CaSO₄) contained in the desulfurization gypsum. In the present invention, this has the effect of reducing carbon emissions due to the effect of replacing the use of cementitious binders.

[0061] In the present invention, it is preferable that the desulfurization gypsum be included in the solidification agent composition in a range of 10 to 30 parts by weight.

[0062] In the present invention, the combined heat and power plant ash is an ash generated after burning coal, biomass, waste, etc., as fuel in a combined heat and power plant. When used in cementitious binders, it assists the function of cement by performing pozzolanic reactions, thereby promoting cement hydration reactions with SiO₂, Al2O₃, etc., and increasing strength. Additionally, fine particles fill the pores of the cement to form a dense structure, and by reducing the total heat of hydration through cement substitution, it reduces crack formation. Furthermore, when included in solidification agents, it plays a role in increasing resistance to sulfate and alkali-silica reactions.

[0063] In the present invention, it is preferable that the combined heat and power plant ash be included in the solidification agent composition in a range of 1 to 10 parts by weight.

[0064] In the present invention, the calcium carbonate can be used as a filler, auxiliary admixture, or functional additive in a solidification composition, and can perform functions such as improving the workability of the solidification agent, controlling shrinkage, and enhancing economic efficiency. Specifically, the calcium carbonate is a fine particle that fills the space between cement particles to enable a dense structure and lowers the porosity to improve water resistance and durability, improves the flowability and pumpability of the solidification agent, and reduces drying shrinkage to reduce the occurrence of cracks.

[0065] In the present invention, it is preferable that the calcium carbonate be included in the solidification agent composition in a range of 1 to 15 parts by weight.

[0066] Next, the surface-modified silica fume with nanosilica used in the eco-friendly solidification agent composition of the present invention will be described.

[0067] In the present invention, the silica fume surface-modified with nanosilica is used to densify the fine pores in the cement solidification agent.

[0068] Nano silica (NS) is a fine particle material that possesses the characteristics of a pozzolanic material. Although its chemical composition and structure are identical to silica fume, a common pozzolanic material, its nano-sized particles make it much more effective at filling fine pores compared to micro-sized pozzolans.

[0069] It is known that when the above nano silica is incorporated into cement, the dissolved silica component reacts with calcium hydroxide produced during the cement hydration reaction to form additional calcium silicate hydrate (CSH), thereby contributing to strength development. It is also known that by using ultrafine particles to densify the hardened body, cement and ultrafine powder are mixed, and a high-performance water-reducing agent is used to increase the dispersion effect, fluidity is secured with a small amount of mixing water, and porosity can be reduced by forming a dense hydrated hardened body.

[0070] However, there are various problems caused by the fine particle size. For instance, the dispersibility of nanosilica is considered a critical issue because nanosilica exhibits a tendency to aggregate, potentially forming weak points within the matrix. Additionally, the increased specific surface area can reduce the fluidity of cementitious materials, negatively impacting workability. In particular, nanosilica, with its nano-sized particles, fails to disperse evenly within cement hydration products due to the van der Waals repulsion acting between particles. Since it forms aggregates on its own, methods such as dispersing it in aqueous solutions or utilizing ultrasonic dispersion are employed. Furthermore, due to the significantly low specific gravity resulting from the nano-sized particle size, incorporating it in a fine powder state may result in airborne particles, potentially preventing improvements in physical properties during mix design.

[0071] In this invention, a special method is used to solve the problem of such nanosilica.

[0072] That is, the present invention is characterized by applying nanosilica to a solidification agent using silica fume as a carrier, and specifically, the following method is used.

[0073] That is, the present invention uses a method of first forming nanosilica using silica and then introducing it into silica fume, wherein the nanosilica used is nanosilica containing hydroxyl and carboxyl groups obtained by causing a sol-gel reaction between an amphiphilic nonionic silane and an amphiphilic ionic silane.

[0074] More specifically, to synthesize nanosilica having organic and inorganic groups, amphiphilic nonionic silanes and amphiphilic anionic silanes are used. In amphiphilic anionic silanes, the hydrophobic silane group portion is detached when a sol-gel reaction occurs, and an amphoteric material is formed in which a hydrophilic carboxylic acid portion and a hydrophobic polypropylene oxide group are combined, and in amphiphilic nonionic silanes, the silane group is detached when a sol-gel reaction occurs, forming nanosilica in which hydroxyl groups exist on the silica surface.

[0075] Ultimately, when an amphiphilic nonionic silane and an amphiphilic anionic silane are mixed to induce a sol-gel reaction, nanosilica is formed in which hydroxyl and carboxyl groups exist on the surface of the silica.

[0076] In the present invention, the nanosilica obtained by the above method is applied to a carrier using a special method to express its inherent properties and solve problems, and is then applied to the solidification agent composition according to the present invention.

[0077] In the present invention, silica fume is used as the carrier of the nanosilica.

[0078] The above silica fume is a material concentrated from gases discharged from a blast furnace, containing a large amount of amorphous silicon dioxide, and consists of very fine, symmetrical particles. The silica fume exhibits a high binding affinity with alkali ions and plays a role in improving the miscibility between constituent components during the placement of cementitious solidification agents. The density of the silica fume is 2.0 to 2.2 g / cm³. 3 and the specific surface area is 150,000–200,000 cm² 2 It may be an ultrafine particle having a fineness of / g. In addition, the average particle size of the silica fume may be 0.2 to 0.5 μm.

[0079] The types of silica fume mentioned above are broadly classified into powder and granular silica fume. Powdered silica fume refers to a form obtained during the dust collection process without a separate processing step; similar to nanosilica, it has fine particles and low density, which severely limits its transportation and use. On the other hand, granular silica fume is produced by condensing powdered silica fume through a separate process to facilitate transportation and handling. In the granular silica fume process, powdered silica fume is loaded into a sealed space and dispersed using compressed air; during this process, the particles intertwine to form clumps. Since these clumps are relatively weakly bound, if they are incorporated into cementitious materials in a dry state, they easily break down when mixed with water.

[0080] The present invention is characterized by incorporating an appropriate amount of nano silica into the process of manufacturing powdered silica fume into a granular form for the handling and efficient use of nano silica, thereby using it as a dry raw material, namely, silica fume surface-modified with nano silica.

[0081] In the present invention, the surface modified silica fume with nano silica can be manufactured by stably and evenly fixing nano silica to the surface of silica fume particles using a dry wind, for example, a completely dry wind of 10 to 30 m / s, in a sealed space.

[0082] In the present invention, it is preferable that the nanosilica be mixed in a ratio of 1 to 10 parts by weight relative to 100 parts by weight of the silica fume. If the nanosilica is less than 1 part by weight relative to the silica fume, the probability of the nanosilica adhering to the surface of the silica fume may decrease, and if the ratio exceeds 10 parts by weight, the amount that can be incorporated is exceeded, causing the nanosilica to aggregate and making dispersion difficult; therefore, it is preferable to mix within the above ratio range.

[0083] In the present invention, it is preferable that the silica fume surface-modified with nanosilica be included in the environmentally friendly ground solidification agent composition according to the present invention in a range of 3 to 10 parts by weight.

[0084] Furthermore, the above xanthan gum is a natural polysaccharide polymer material and is a naturally derived material. It contains glucuronic acid (-COO-), which allows it to bind strongly with water, and as a result, xanthan gum has the ability to form a gel with high viscosity.

[0085] Xanthan gum does not induce ground solidification through chemical reactions like cement, but rather acts as a natural adhesive that binds soil particles together. By coating the surface of soil particles to increase inter-particle bonding and reinforcing inter-particle cohesion due to its high adhesive strength, it can play a role in increasing compressive strength, shear strength, and erosion resistance.

[0086] In addition, the above xanthan gum has the property of being able to absorb hundreds of times its own weight in water, so when used in solidification agents, it can reduce drying cracks, mitigate rapid changes in moisture content, and increase the curing stability of the solidification agent.

[0087] In addition, the above xanthan gum can reduce the phenomenon of soil being washed away by rainfall or rainwater, so it can be used for slope stabilization, slope greening, and desertification prevention, and the gel within the xanthan gum can partially fill the pores, thereby reducing the rate of water infiltration and improving water-blocking performance.

[0088] In the present invention, it is preferable that the xanthan gum be included in a range of 1 to 10 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0089] In addition, in the present invention, the redispersible polymer powder plays a role in improving adhesion strength by forming a polymer bridge between the existing soil and the solidifying agent, and also plays a role in improving flexural strength, impact resistance, and durability. Specifically, the redispersible polymer resin redisperses upon contact with water to form a polymer emulsion, and forms a composite structure with the cement hydrate by forming a continuous polymer film during the cement hydration process. Accordingly, it is possible to provide effects such as improved adhesion strength between soil and cement, reduced drying shrinkage cracks, improved flexural strength, improved impact resistance, improved salt resistance, and improved freeze-thaw resistance.

[0090] In the present invention, it is preferable that the redispersible polymer powder be included in a range of 1 to 5 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0091] In addition, the shrinkage reducing agent in the present invention is intended to reduce the drying shrinkage of the solidifying agent and may include one or more selected from polyoxyalkylene alkyl ethers, polypropylene glycol, polyethylene glycol, and glycol ether-based compounds.

[0092] In the present invention, it is preferable that the shrinkage reducing agent be included in a range of 0.2 to 1.2 parts by weight based on 10 to 40 parts by weight of the cementitious binder according to the present invention.

[0093] In the present invention, the fine quartz powder may be used by coating the surface of the crushed glass powder with a water-soluble resin, such as EVA (ethylene vinyl acetate copolymer) resin or acrylic resin. For example, finely crushed waste oil powder may be used as the glass powder. Alternatively, a water-soluble resin may be sprayed onto the crushed material, kneaded into a paste, and then calcined using a kiln. At this time, it is preferable to conduct the calcination at a temperature range that forms a porous structure in the glass phase without decomposing the water-soluble resin on the surface. After such calcination, a sieving process may be further performed to separate the particles by size.

[0094] The above quartz fine powder is characterized by having a double structure of a core-shell structure in which the interior has a porous structure and the surface is coated with a water-soluble resin through calcination treatment.

[0095] The above quartz fine powder has a shape close to spherical due to the calcination treatment, so it is a lightweight material, but the degradation of physical properties such as strength and durability can be minimized. At the same time, although it has a porous structure, the water absorption rate is reduced by the surface resin coating, so the water-to-cylinder ratio (W / C) in the binder can be reduced, which has the advantage of improving workability and resolving problems caused by excess water, and it plays a role in improving chemical resistance and durability through the calcination treatment.

[0096] In the present invention, it is preferable that the fine quartz powder be included in a range of 0.1 to 10 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0097] In addition, the high-performance water reducer in the present invention is intended to improve the fluidity and fillability of the solidifying agent and reduce the unit water content, and may include one or more selected from polycarboxylate ether-based water reducers, naphthalene sulfonate-based water reducers, melamine sulfonate-based water reducers, and lignin sulfonate-based water reducers.

[0098] In the present invention, it is preferable that the high-performance water reducer be included in a range of 0.2 to 1.2 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0099] In addition, the thickener in the present invention is intended to control the viscosity and water retention of the solidifying agent and may include one or more selected from cellulose ether-based thickeners, natural gum-based thickeners, acrylic-based thickeners, urethane-based thickeners, and inorganic viscosity modifiers.

[0100] In the present invention, it is preferable that the thickener be included in a range of 0.02 to 0.2 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0101] In addition, the fibers in the present invention are intended to prevent drying shrinkage and cracking of the solidification agent and may include steel fibers, carbon fibers, glass fibers, ollon fibers, polypropylene fibers, PVA fibers, cellulose fibers, PET fibers, or fibers mixed therewith with a length of 0.5 to 1.0 mm.

[0102] In the present invention, it is preferable that the fiber be included in a range of 0.1 to 1.0 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0103] In addition, the CSA expansion agent in the present invention is an expansion agent comprising a calcium sulfoaluminate-based mineral, and can compensate for the drying shrinkage and self-shrinkage of the solidification agent by generating ettringite during the hydration process to induce volume expansion. Accordingly, cracking and delamination can be suppressed, interfacial adhesion with existing soil can be improved, and long-term durability can be enhanced.

[0104] In the present invention, it is preferable that the CSA expansion agent be included in a range of 0.01 to 0.2 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0105] In addition, in the present invention, the lithium carbonate can be used as a hydration accelerator to promote the initial hydration reaction of the solidification agent and improve early strength development. The lithium carbonate can promote the hydration reaction of cement and CSA expansive agent to shorten the setting time and improve initial compressive strength and bond strength, suppress alkali-silica reactions to improve long-term durability, and densify the internal structure to reduce chloride penetration and the progression of neutralization.

[0106] In the present invention, it is preferable that the lithium carbonate be included in a range of 0.01 to 1.0 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0107] In order to constitute the ground solidification agent composition of the present invention, a modified active binder is also included, and it is preferable that the modified active binder be included in the solidification agent composition in a range of 20 to 40 parts by weight based on 10 to 40 parts by weight of the cementitious binder. If the modified active binder is less than 20 parts by weight, the formation of ettringite is low and long-term strength development may be reduced, and if it exceeds 40 parts by weight, initial strength may not be secured due to reduced initial reactivity and delayed setting, so it is preferable to use it within the above range.

[0108] In the present invention, the modified active binder is prepared by mixing circulating fluidized bed boiler ash and wet gypsum generated in the desulfurization process of a power plant with silica fume, fly ash, and a grinding aid to form a mixed raw material, and then grinding this material in a fine grinding equipment to obtain a fineness of 6,000 to 9,000 cm⁻¹. 2 It is characterized by being / g.

[0109] First, the aforementioned circulating fluidized bed boiler ash refers to circulating fluidized bed boiler ash generated in power plants, such as thermal power plants or combined heat and power plants, and specifically refers to ash generated in circulating fluidized bed boilers that use petro-coke fuel in part or entirely. Specifically, the circulating fluidized bed boiler ash may contain unreacted CaO (quicklime) and CaSO4 (anhydrous gypsum) from which the desulfurization process reaction has been completed as main components.

[0110] In addition, the circulating fluidized bed boiler ash mentioned above may be ash generated from a circulating fluidized bed boiler that uses a mixture of bituminous coal and petro-coke fuel. Most combined heat and power plants using circulating fluidized bed boilers use various types of low-grade bituminous coal or mix with petro-coke, and the circulating fluidized bed boiler ash generated in the above power plants may be ash generated from a circulating fluidized bed boiler that uses fuel mixed with, for example, 40 to 50 parts by weight of bituminous coal and 50 to 60 parts by weight of petro-coke.

[0111] The above-mentioned wet gypsum is a type of gypsum whose main component is calcium sulfate alpha-hemihydrate, specifically referring to alpha(α) type calcined gypssum.

[0112] The wet gypsum used in the present invention has the property of causing cement to harden very rapidly. In particular, since rapid hardening of the cement occurs due to residual moisture present in the wet gypsum, the wet gypsum is difficult to include in general solidification agent compositions.

[0113] However, the present invention is characterized by the fact that residual moisture present in the wet gypsum can be used as a raw material to improve the reactivity of blast furnace slag and combined heat and power plant ash.

[0114] In the present invention, the wet gypsum may have a moisture content of 5 to 30 weight percent.

[0115] The above residual moisture can react with calcium oxide (CaO) of the circulating fluidized bed boiler ash as described above to form Ca(OH)2.

[0116] In the present invention, the formed Ca(OH)2 can form CaCO3 through a carbonation process.

[0117] The above carbonation process involves injecting high-temperature carbon dioxide gas under pressure to react, and Ca(OH)2 formed by the reaction between residual moisture present in the wet gypsum and CaO present in the circulating fluidized bed boiler ash is then converted into CaCO3 through a high-temperature carbon dioxide injection process.

[0118] The CaCO3 formed through the above carbonation process contains more than 30% calcite, which can be analyzed by mineral analysis (XRD analysis).

[0119] In the present invention, reacting Ca(OH)2 with CaCO3 through the carbonation process results in the capture of carbon dioxide, so there is an effect of receiving benefits from reducing carbon without paying a carbon tax.

[0120] In addition, Ca(OH)2, obtained by reacting the CaO contained in the circulating fluidized bed boiler ash with the residual moisture in the wet gypsum, is a strong alkaline component with a pH of 12 or higher, and it serves as an activator for blast furnace slag, silica fume, and fly ash, and plays a role in improving the reactivity of silica fume and fly ash, which have somewhat weak reactivity.

[0121] In this way, circulating fluidized bed boiler ash generated as a byproduct of power plants can be subjected to a carbonation process, thereby reducing carbon emissions. At the same time, the strong alkalinity of the solidification agent can be maintained by the CaO and Ca(OH)2 components remaining in the byproduct, which can enhance the reactivity of blast furnace slag, silica fume, and fly ash as stimulants, thereby obtaining two effects.

[0122] In addition, circulating fluidized bed boiler ash contains CaSO4, which acts as a sulfate stimulant for blast furnace slag, silica fume, and combined heat and power plant ash (e.g., fly ash).

[0123] In the present invention, the modified active binder is prepared by mixing circulating fluidized bed boiler ash and wet gypsum generated in the desulfurization process of a power plant with silica fume, fly ash, and a grinding aid to form a mixed raw material, and then grinding this material in a fine grinding equipment to obtain a fineness of 6,000 to 9,000 cm⁻¹. 2 It is characterized by being / g

[0124] At this time, it is preferable to use a mixture of each component constituting the above-mentioned mixed raw material in the ratio of 62 to 80 parts by weight of silica fume, 10 to 20 parts by weight of fly ash, 5 to 10 parts by weight of circulating fluidized bed boiler ash, 5 to 8 parts by weight of wet gypsum, and 0.01 to 2 parts by weight of grinding aid.

[0125] In the present invention, the grinding aid is intended to increase the surface area of ​​the cement and the modified active binder to increase reactivity and to easily form fine particles. In the present invention, the grinding aid may use one or more combinations selected from monoethylene glycol, diethylene glycol, propylene glycol, triethanolamine, triisopropanolamine, and amine acetate.

[0126] More specifically, in the present invention, a mixture of diethylene glycol and triisopropanolamine may be used as a grinding aid, and it is preferable to mix diethylene glycol and triisopropanolamine in a weight ratio of 70 to 90 and 10 to 30, respectively. At this time, if the weight ratio of diethylene glycol is less than 70, the grinding performance of each component forming the modified active binder is reduced, and if the weight ratio of triisopropanolamine is less than 10, a coating phenomenon may occur inside the mill during grinding, which may reduce the grinding efficiency.

[0127] In addition, in the present invention, it is preferable that the grinding aid be included in the mixed raw materials constituting the modified active binder in a range of 0.01 to 2 parts by weight.

[0128] The mixed raw material constituting the modified active binder containing the above grinding aid can be appropriately selected from known grinding methods and, although not particularly limited, can be ground using fine grinding equipment such as a vibratory mill, pin mill, fine impact mill, ball mill, or vertical mill.

[0129] At this time, the grinding treatment using the fine grinding equipment may be performed for approximately 120 to 240 minutes, and preferably for 150 to 210 minutes. The fineness of the modified active binder fine powder formed at this time is 6,000 to 9,000 cm⁻¹. 2 Grinding can be performed to make it / g.

[0130] In the present invention, the ground solidification agent composition may further comprise 0.05 to 5.0 parts by weight of cross-linked acrylic resin based on 10 to 40 parts by weight of cementitious binder.

[0131] In the present invention, the crosslinked acrylic resin is obtained by ether bonding using 2-HEMA (Hydroxyethyl Methacrylate) or GMA (Glycidyl Methacrylate) with hexamethoxymethyl melamine as a crosslinking agent, and it is preferable to use one having a weight-average molecular weight in the range of 5,000 to 100,000.

[0132] The above-mentioned cross-linked acrylic resin forms a network structure in its polymer state, which can protect the solidifying agent and improve durability and weather resistance. It also plays a role in forming a solidifying agent surface with high strength and excellent surface strength due to its high density.

[0133] The above cross-linked acrylic resin is a fine cationic acrylic copolymer that has excellent adhesion to anionic soil, and by using fine resin, excellent results in penetration resistance, water resistance, and weather resistance can be observed.

[0134] In the present invention, it is preferable that the cross-linked acrylic resin be included in a range of 0.05 to 5.0 parts by weight based on 10 to 40 parts by weight of the cementitious binder.

[0135] The ground solidification agent composition according to the present invention, obtained as described above, can solidify ground soil by mixing it into the soil in an appropriate amount according to the moisture content of the soil to be solidified and the original ground soil, as well as the target compressive strength. That is, when the moisture content of the soil is high or the target compressive strength is high, the amount of the solidification agent composition can be increased.

[0136] The amount of the ground solidification agent composition used in the present invention can be mixed and used in a range of 1 to 30 parts by weight based on 100 parts by weight of the original ground soil. If the amount of the ground solidification agent composition used is less than 1 part by weight, the solidification effect may decrease, and if it exceeds 30 parts by weight, it is difficult to increase the strength further and only the manufacturing cost increases, so it is preferable to mix and use it within the above range.

[0137] The ground solidification method using the ground solidification agent composition according to the present invention can be specifically carried out in the following order.

[0138] That is, the method may be configured to include the steps of first mixing the ground soil to be solidified with the eco-friendly ground solidification agent composition according to the present invention, stirring the mixture of the ground soil and the solidification agent composition, and then pressurizing and solidifying the mixed and stirred mixture.

[0139] Here, the term "ground" refers to ground lacking sufficient bearing capacity, and the constituent soil may include clay, silt, or peat, which are soft and highly compressible. When a structure is built on such ground, problems arise such as ground failure or consolidation settlement. Such ground is typically characterized by a high water content and a large amount of organic matter, and if a large amount of ordinary Portland cement is used, there is a problem that it may contain a large amount of harmful heavy metals such as hexavalent chromium.

[0140] The ground solidification method according to the present invention first mixes the ground soil and the eco-friendly ground solidification agent composition according to the present invention in an appropriate ratio. At this time, the mixing ratio may vary depending on the required physical properties, but it is preferable that the solidification agent composition be mixed in a ratio of 1 to 30 parts by weight based on 100 parts by weight of soil.

[0141] Next, the soil and the solidification agent composition are stirred. General equipment capable of uniform mixing can be used; for example, a stirrer equipped with a 4-row multi-screw at an 8-degree angle can be used to stir evenly while rotating at a speed of 500 to 700 RPM. At this time, a grinding device (e.g., a roll mill) may be equipped in the stirring device to finely pulverize the soil particles before mixing and stirring. After mixing and stirring in this manner, the ground solidification process can be completed by applying pressure of 1 to 5 tons to the stirred soil and solidifying it.

[0142] Hereinafter, preferred embodiments of the present invention are described so that a person skilled in the art to which the present invention pertains can more easily implement the present invention.

[0143] <Preparation Example 1> Preparation of a low-cement-based binder

[0144] Industrial by-products including incineration ash and combustion residues generated from a combined heat and power plant, as well as waste gypsum and waste lime, were prepared. Subsequently, waste glass fibers generated during the glass fiber manufacturing process were first crushed, and the prepared industrial by-products and waste glass fibers were mixed in a ratio of 100:50 by weight, respectively. The mixed components were then fed into a crushing device (ball mill) and crushed to collect a powder mixture. Based on 100 by weight of the obtained powder mixture, 75 by weight of Portland cement was mixed to obtain a powder component. A low-cement-based binder was obtained by mixing 100 by weight of the obtained powder component with 35 by weight of a mixture of calcium aluminate, calcium sulfoaluminate, magnesium aluminate, and magnesium sulfoaluminate.

[0145] <Preparation Example 2> Preparation of Modified Active Binder

[0146] The modified active binder according to the present invention was prepared by mixing 70 parts by weight of silica fume, 15 parts by weight of fly ash, 8 parts by weight of circulating fluidized bed boiler ash, and 6 parts by weight of wet gypsum (moisture content 21 wt%) in a vibratory mill using 1 part by weight of a liquid aid (a grinding aid in which DEG (Diethyleneglycol) and TIPA (Triisopropanolamine) are mixed in an 80:20 ratio) through a modification treatment.

[0147] <Example 1> Preparation of an eco-friendly ground solidification agent composition

[0148] A solidification agent composition was prepared by mixing 35 parts by weight of the low-cement-based binder obtained in Preparation Example 1, 15 parts by weight of blast furnace slag, 15 parts by weight of desulfurization gypsum, 5 parts by weight of combined heat and power plant ash, 3 parts by weight of calcium carbonate, 5.5 parts by weight of silica fume surface-modified with nanosilica, 3.5 parts by weight of xanthan gum, 2 parts by weight of redispersible polymer powder, 0.5 parts by weight of shrinkage reducing agent, 0.9 parts by weight of fine quartz powder, 0.5 parts by weight of high-performance water reducer, 0.09 parts by weight of thickener, 0.8 parts by weight of fiber, 0.05 parts by weight of CSA expansion agent, 0.05 parts by weight of lithium carbonate, and 25 parts by weight of the modified active binder obtained in Preparation Example 2.

[0149] The above-mentioned nanosilica surface-modified silica fume was prepared by performing a sol-gel reaction between an amphiphilic nonionic silane and an amphiphilic anionic silane to produce nanosilica containing hydroxyl and carboxyl groups, introducing the obtained nanosilica into a facility that condenses powdered silica fume into granular silica fume at a ratio of 5 parts by weight to 100 parts by weight of silica fume, and fixing the nanosilica onto the surface of silica fume particles using a completely drying wind of about 2.0 m / s in a sealed space.

[0150] <Example 2> Preparation of an eco-friendly ground solidification agent composition

[0151] The same as Example 1 is used, except that 1.5 parts by weight of crosslinked acrylic resin is additionally included in the solidification agent composition.

[0152] The above cross-linked acrylic resin is obtained by ether bonding using 2-HEMA (Hydroxyethyl Methacrylate) and hexamethoxymethyl melamine as a crosslinking agent, and a resin with a weight-average molecular weight of about 60,000 was used.

[0153] <Example 3> Preparation of an eco-friendly ground solidification agent composition

[0154] The same as Example 1 is used, except that 7.5 parts by weight of xanthan gum is included in the solidifying agent composition.

[0155] <Comparative Example 1> Preparation of a ground solidification agent composition

[0156] The same as Example 1 is carried out, except that the solidifying agent composition does not include xanthan gum.

[0157] <Comparative Example 2> Preparation of a ground solidification agent composition

[0158] The same as Example 1 is carried out, except that the solidification agent composition does not include a modified active binder.

[0159] <Comparative Example 3> Preparation of a ground solidification agent composition

[0160] The same as Example 1 is carried out, except that the solidification composition does not include silica fume surface-modified with nano silica.

[0161] Table 1 below shows the physical properties (compressive strength) of the solidification agent compositions according to Examples 1 to 3 and Comparative Examples 1 to 3 above.

[0162] division Compressive strength at 3 days (MPa) Compressive strength at 7 days (MPa) Compressive strength at 28 days (MPa) Example 1 0.94 1.6 2.8 Example 2 0.95 1.8 3.3 Example 3 0.96 1.9 3.5 Comparative Example 1 0.85 1.5 2.6 Comparative Example 2 0.82 1.7 2.7 Comparative Example 3 0.86 1.6 2.7

[0163] From the results of Table 1 above, it was confirmed that the eco-friendly solidification agent composition according to the present invention is equivalent to or better than the samples of the comparative example.

[0164] Next, the results obtained by analyzing the physicochemical properties of ordinary Portland cement and the low-cement-based binder according to the present invention are shown in Tables 2 and 3, respectively.

[0165] Density (g / cm³) Fineness (cm² / g) Stability (%) Chemical composition (%) CaO SiO2 AL2O3 Fe2O3 MgO SO3 3.15 3.144 0.05 63.4 22.0 5.27 3.44 2.13 1.96

[0166] Density (g / cm³) Fineness (cm² / g) Chemical composition (%) SiO2 AL2O3 Fe2O3 CaO MgO SO3 TiO2 2.9 4718 27.5 13.0 4.1 40.4 4.8 6.8 0.69

[0167] From the experimental results above and other experimental results, it has been confirmed that the eco-friendly ground solidification composition according to the present invention replaces the cement previously used to reinforce the ground, thereby minimizing the amount of cement used and instead mixing and using industrial by-products such as blast furnace slag powder and combined heat and power plant ash, and using nano-silica surface-modified silica fume, xanthan gum, fine quartz powder, and modified active binder to enhance strength and increase resource circulation effects by recycling waste resources, while simultaneously having an eco-friendly effect by reducing the amount of cement used, resulting in less leaching of heavy metals such as hexavalent chromium, and providing a continuous solidification solution by utilizing xanthan gum, a naturally derived biopolymer, and exhibiting excellent physical properties such as compressive strength and flexural strength, as well as chemical and corrosion resistance. Furthermore, compared to general cement-based materials currently in use, it has excellent environmental and economic properties, as well as excellent liquefaction and seismic reinforcement effects.

[0168] As described above, preferred embodiments of the present invention have been disclosed in this specification. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the invention and to aid in understanding the invention, and are not intended to limit the scope of the invention. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present invention may be implemented.

Claims

Claim 1 An eco-friendly ground solidification agent composition comprising 10 to 40 parts by weight of a cementitious binder, 10 to 40 parts by weight of blast furnace slag, 10 to 30 parts by weight of desulfurization gypsum, 1 to 10 parts by weight of combined heat and power plant ash, 1 to 15 parts by weight of calcium carbonate, 3 to 10 parts by weight of silica fume surface-modified with nanosilica, 1 to 10 parts by weight of xanthan gum, 1 to 5 parts by weight of redispersible polymer powder, 0.2 to 1.2 parts by weight of shrinkage reducing agent, 0.1 to 10 parts by weight of fine quartz powder, 0.2 to 1.2 parts by weight of high-performance water reducer, 0.02 to 0.2 parts by weight of thickener, 0.1 to 1.0 parts by weight of fiber, 0.01 to 0.5 parts by weight of CSA expansion agent, 0.01 to 1.0 parts by weight of lithium carbonate, and 20 to 40 parts by weight of a modified active binder. Claim 2 An eco-friendly ground solidification composition according to claim 1, wherein the cementitious binder is characterized by using a low-cementity binder, and wherein the low-cementity binder comprises 100 parts by weight of a powder component obtained by a method of preparing industrial by-products including incineration ash, waste gypsum, waste lime, and combustion residue generated from an incineration facility, and preparing waste glass fibers generated during the glass fiber manufacturing process, mixing the prepared industrial by-products and waste glass fibers in a ratio of 100:1 to 100 parts by weight each, feeding the mixed components into a grinding device and grinding to collect a powder mixture, and then mixing 50 to 100 parts by weight of Portland cement based on 100 parts by weight of the obtained powder mixture, and a mixture of calcium aluminate, calcium sulfoaluminate, magnesium aluminate, and magnesium sulfoaluminate in a weight ratio of 20 to 50. Claim 3 In claim 1, the modified active binder is formed by mixing circulating fluidized bed boiler ash and wet gypsum generated in the desulfurization process of a power plant with silica fume, fly ash, and a grinding aid to form a mixed raw material, and then grinding the mixture in a fine grinding device to obtain a fineness of 6,000 to 9,000 cm² 2 An eco-friendly soil solidification agent composition characterized by having / g. Claim 4 The eco-friendly ground solidification composition according to claim 1, wherein the eco-friendly ground solidification composition further comprises 0.05 to 5.0 parts by weight of a cross-linked acrylic resin based on 10 to 40 parts by weight of a cementitious binder, and wherein the cross-linked acrylic resin is obtained by ether bonding using 2-HEMA (Hydroxyethyl Methacrylate) or GMA (Glycidyl Methacrylate) with hexamethoxymethyl melamine as a crosslinking agent, and wherein a resin having a weight-average molecular weight in the range of 5,000 to 100,000 is used. Claim 5 A ground reinforcement method characterized by reinforcing the ground using an eco-friendly ground solidification agent composition according to any one of claims 1 to 4.