Eco-friendly pavement method capable of securing strength and having excellent carbon emission reduction effect by utilizing on-site soil
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2026-08-13
Smart Images
Figure KR2025005765_13082026_PF_FP_ABST
Abstract
Description
An eco-friendly paving method that utilizes on-site soil to achieve excellent carbon emission reduction and ensure strength.
[0001] The present invention relates to an eco-friendly paving method that utilizes on-site soil to achieve excellent carbon emission reduction effects and secure structural strength. Specifically, it relates to a technology that effectively reduces carbon emissions caused by dump trucks and on-site equipment using diesel fuel in conventional road construction by eliminating the need to produce aggregates for paving construction through separate equipment or methods or transport them over long distances using dump trucks, and by allowing the excavated soil generated at the construction site to be used directly on-site for compaction construction.
[0002] Furthermore, the present invention relates to an eco-friendly paving method (hereinafter referred to as the "HSSM method") that not only contributes to achieving Korea's NDC targets through such carbon emission reduction, but also allows the reduction results generated from greenhouse gas reduction projects through climate change cooperation with developing countries to be reflected in the NDC performance of both countries through corresponding adjustments.
[0003] Furthermore, the present invention relates to a technology capable of revitalizing the global carbon market and promoting carbon reduction activities in the private sector by supporting the conversion of reduction achievements into internationally tradable credits through voluntary participation in the carbon market for carbon reduction projects, thereby enabling the achievement of additional carbon reduction targets.
[0004] The Conference of Parties (COP) of the United Nations Framework Convention on Climate Change (UNFCCC) is a forum for discussing the implementation of the UNFCCC adopted in 1992, where 197 parties have gathered annually to review international efforts to address climate change and formulate new action plans.
[0005] In particular, starting with the Paris Agreement adopted in 2015, detailed implementation rules for Article 6 of the Paris Agreement, which is the biggest point of contention among nations, have been established through the COP held annually. Article 6 of the Paris Agreement stipulates international carbon markets and cooperative approaches, providing an important framework for achieving global greenhouse gas reduction targets. It aims to reduce greenhouse gases in a cost-effective manner and enhance global climate adaptation through voluntary cooperation among Parties to achieve their Nationally Determined Contributions (NDCs). Specifically, it is centered on Articles 6.2 (Cooperative Approach), 6.4 (Centralized Mechanisms), and 6.8 (Non-Market Approach).
[0006] In particular, Article 6 of the Paris Agreement provides a new framework for the international carbon market and concerns the operation of the international carbon market and the carbon credit trading system. Article 6.2 provides a mechanism for trading "Internationally Transferred Reduction Results (ITMOs)" through bilateral or multilateral cooperation between countries, and Article 6.4 supports a market, as an international mechanism managed under the UNFCCC, where greenhouse gas reduction / removal credits can be generated and traded through individual projects or activities.
[0007] At COP29 held in Azerbaijan in 2024, the foundation for an international carbon market was laid by agreeing on detailed implementation rules for Article 6 of the Paris Agreement. Through this, detailed guidelines were established regarding the authorization procedures for voluntary international reduction cooperation projects (Article 6.2) and International Transfer Mechanisms (ITMOs), measures to handle discrepancies in reporting by parties, and the operation of the international register. Additionally, standards were established for emission baselines and the scope of carbon removal activities under the Article 6.4 mechanism managed by the Paris Agreement supervisory body.
[0008] All parties to the Paris Agreement are obligated to formulate and submit Nationally Determined Contributions (NDCs) every five years starting from 2020. Submission is not merely a matter of doing; countries must make continuous efforts to implement these NDCs as their medium-term greenhouse gas reduction targets. NDC reduction targets can be broadly categorized into absolute amounts, projected emissions, intensity, and policy and instrument targets. In particular, just as Korea has set a goal to reduce emissions by 40% compared to 2018 levels by 2030, countries are striving to reduce carbon emissions by setting reduction targets relative to a base year and establishing target emission levels.
[0009] In addition, a transparency framework regarding climate action and support is also important, as all Parties are required to submit a Biennial Transparency Report (BTR) to the UN starting in 2024. A system has been established to transparently report climate change-related information, such as greenhouse gas emissions, mitigation and adaptation actions, and matters related to climate finance, technology, and capacity building, with the aim of enhancing transparency among nations and supporting developing countries.
[0010] Korea has set an international reduction target of 37.5 million tons as a supplementary means to achieve its 2030 NDC goals. This involves implementing carbon reduction projects in cooperation with developing countries, coordinating and allocating reduction achievements between the two nations, and reflecting them in their respective NDCs. This figure represents approximately 12.9% of the domestic reduction target (291 million tons) and is the second-largest sector in terms of reduction scale. To achieve future NDC goals, Korea is strengthening public-private cooperation and establishing an institutional framework to enable domestic companies to more actively carry out greenhouse gas reduction projects overseas.
[0011] In addition to government-led international reduction projects, the private sector is actively utilizing Voluntary Carbon Markets (VCMs) to flexibly trade carbon reduction credits generated abroad and secure the potential for additional reductions. Reduction credits traded in VCMs adhere to internationally verified standards and certification systems, and these are continuously being improved to enhance the transparency and reliability of reduction credits. To revitalize VCMs, institutional systems guaranteeing the reliability of internationally verified credits are being gradually established. Furthermore, the introduction of digital technologies, AI, and blockchain is making the tracking and certification of carbon reduction data more precise and transparent, leading to enhanced reliability of reduction credits and increased trading efficiency. Based on this foundation, an environment is being created that enables private companies to participate more actively in VCMs, including through attracting investment.
[0012] Accordingly, the present invention relates to a technology capable of effectively securing carbon reductions and demonstrating sustainability and cost-effectiveness while responding to the launch of the international carbon market and changes in its mechanisms, under the common goal of responding to climate change and achieving carbon neutrality.
[0013] Meanwhile, to pave an asphalt concrete road, the original ground is cut or filled to a certain thickness, and then high-quality soil is compacted according to specifications to form a subgrade layer. On top of this, a base layer and a subbase layer are formed with a thickness of usually 20 to 40 cm using mixed aggregate that passes through a sieve with a diameter of 40 to 200. On top of this, an asphalt concrete base layer (BB-2 #467) is laid to a thickness of 10 to 25 cm, and then an asphalt concrete intermediate layer (WC-4 #67 or BB-3 #57) and a surface layer (WC-2 #78) are laid to a thickness of 5 to 12 cm to complete the asphalt concrete pavement section.
[0014] Conventional asphalt concrete paving methods require the use of aggregates, such as gravel or aggregates that meet specifications, to form the subbase and base layers. However, the supply of aggregates used for these layers is currently inconsistent due to recent restrictions on quarry development and public complaints regarding aggregate crushing operations, leading to serious supply shortages. Furthermore, the scarcity of high-quality natural aggregates results in inadequate specifications and quality, making it difficult to secure bearing capacity. Additionally, the transportation, laying, and compaction of aggregates require significant time, transportation costs, and material expenses. Moreover, the disposal of high-quality soil generated on-site during cutting and excavation processes leads to insufficient resource recycling and disposal costs, causing the issue of on-site soil disposal to become a major social concern.
[0015] The massive carbon emissions generated during the production and transportation of aggregates and excavated soil are recognized as a critical challenge to achieving NDC targets, and there is a growing need to expand the use of carbon reduction technologies and recycled resources to address this issue. To resolve this problem, this invention supports technologies and methods that can contribute to carbon reduction implementation efforts and the achievement of NDC targets in Southeast Asian countries such as Vietnam and Malaysia, as well as South American countries such as Chile and Brazil. Furthermore, it provides reliable credits tradable in the global carbon market by utilizing international reduction mechanisms under Article 6 of the Paris Agreement and voluntary carbon markets.
[0016] In developed countries such as the United States and Europe, efforts have long been made to replace road substructures using soil with the Soil Cement method to solve the problem of aggregate supply. However, according to the latest U.S. Soil Cement specifications, the method mainly involves sieving soil generated from the original ground to a specific particle size (at least 80% of the weight of the soil to be used must pass through a No. 4 sieve) in advance, laying it in the paving area, then laying cement and admixtures directly on top of it, and then using special equipment such as a Soil Stabilizer to pulverize and compact it directly in the paving area. Furthermore, the U.S. Soil Cement specifications require that the entire process from mixing to compaction be completed within two hours due to the problem of immediate hydration reaction occurring when cement and water are mixed.
[0017] Therefore, in the existing soil cement method, although a method of homogeneously mixing for a sufficient amount of time in a mixer or batch plant should be adopted, mixing and compaction work must be performed directly in the pavement area, making it difficult to ensure homogeneous quality, which often results in localized failure to meet strength standards. Furthermore, when a large amount of cement is used to increase strength, the excessive cement content actually increases the likelihood of shrinkage cracks, which becomes a major cause of defects in asphalt concrete pavements.
[0018] In addition, conventional soil cement generally requires a minimum cement content of at least 10 weight percent, which causes problems with soil contamination due to the cement. Furthermore, there is a high possibility of shrinkage cracks occurring during curing, requiring the construction of joints. Additionally, it is difficult to ensure homogeneous quality, which leads to the asphalt concrete being designed to be thick, resulting in reduced economic efficiency and potential environmental pollution.
[0019] To solve the above-mentioned problems, the inventors proposed a method in which a certain amount of cement is mixed with a raw material mixture containing inorganic salts, and then compacted under conditions of a certain moisture content to form a rigid base layer, as disclosed in the previously filed Korean Patent No. 10-1936761. This method has attracted attention as a special paving technology that can replace existing aggregate base layers and sub-base layers by improving the roadbed, significantly reduce construction costs by shortening construction time and reducing material usage by decreasing the thickness of the surface layer, and effectively solve the problem of aggregate shortage.
[0020] However, the technology proposed in the aforementioned patent has limitations in that the carbon emission reduction effect is restricted due to the relatively high amount of cement used, and the need for further improvement in terms of strength and durability was raised as the substructure is formed using only a sub-base layer without a base layer. Accordingly, there was a need for the present invention to develop a new paving method capable of solving the aforementioned problems and simultaneously achieving carbon emission reduction and improved strength and durability.
[0021] <Related Prior Art Literature>
[0022] 1. Republic of Korea Published Patent No. 10-2014-0095774
[0023] 2. Republic of Korea Published Patent No. 10-2016-0069559
[0024] 3. Republic of Korea Registered Patent No. 10-0623007
[0025] 4. Republic of Korea Registered Patent No. 10-0990663
[0026] The present invention was developed to solve the problems of the conventional technology described above, and aims to provide a technology that can effectively reduce carbon emissions caused by diesel-powered dump trucks and on-site equipment in existing road construction by eliminating the need to produce aggregates for paving construction through separate equipment or methods or transport them over long distances using dump trucks, and by enabling the use of excavated soil generated at the construction site directly for compaction construction on-site.
[0027] Furthermore, the present invention aims to provide an eco-friendly paving method (hereinafter referred to as the "HSSM method") that not only contributes to achieving Korea's NDC targets through such carbon emission reduction, but also enables the reduction results generated from greenhouse gas reduction projects through climate change cooperation with developing countries to be reflected in the NDC performance of both countries through corresponding adjustments.
[0028] Furthermore, the present invention aims to provide a technical foundation capable of revitalizing the global carbon market and promoting carbon reduction activities in the private sector by supporting the conversion of reduction achievements into internationally tradable credits through voluntary participation in the carbon market for carbon reduction projects, thereby enabling the achievement of additional carbon reduction targets.
[0029] In addition, it is intended to provide an eco-friendly paving technology that can satisfy the required strength without using a large amount of cement like conventional construction methods, and can also enhance durability and internal toughness, thereby reducing carbon emissions from cement production and improving stability, and can also reduce the thickness of the surface layer by up to 50%, which can further reduce carbon emissions from the production, transportation, and laying of surface materials such as asphalt concrete.
[0030] As a means of solving the above-mentioned problem, the present invention is,
[0031] (A) A first step of obtaining a raw material mixture by mixing 10~30 wt% sodium chloride, 10~25 wt% calcium chloride monohydrate, 10~25 wt% calcium chloride, 5~10 wt% sodium triphosphate, 5~10 wt% sodium sulfate, 2~5 wt% sodium lignosulfonate, 3~6 wt% sodium bicarbonate, 1~3 wt% aluminum sulfate, 1~3 wt% calcium carbonate, and 1~3 wt% calcium superphosphate;
[0032] (B) A second step of obtaining a soil mixture by mixing 100 parts by weight of original ground soil and 5 to 8 parts by weight of cement, and further mixing a solution obtained by dissolving 0.2 to 0.3 parts by weight of the raw material mixture obtained in (A) in water;
[0033] (C) A third step of forming a subbase and a base layer by further mixing 0.01 to 1.0 parts by weight of toughness reinforcing agent powder and 0.01 to 3.0 parts by weight of durability reinforcing agent powder based on 100 parts by weight of the soil mixture obtained in (B) above, laying it on a compacted roadbed, and compacting it with a roller; and
[0034] (D) A fourth step of forming a surface layer by laying a surface layer material on the sub-base layer and base layer formed in (C) above and compacting it with a roller; the present invention provides an eco-friendly paving construction method characterized by comprising: (D) a fourth step of forming a surface layer by laying a surface layer material on the sub-base layer and base layer formed in (C) above and compacting it with a roller.
[0035] In one embodiment of the present invention, the original ground soil in (B) is characterized by using soil collected from the original ground that has been cut or excavated, or excavated soil generated at a construction site of an apartment, parking lot, general road, or industrial road with a diameter of 40 mm or less, separated and used as is without separation.
[0036] In addition, in one embodiment of the present invention, the soil mixture in (B) is characterized by being performed in such a way that homogeneous quality can be ensured by securing the mixing time, such that the hydration reaction with cement is suppressed for 6 to 24 hours after mixing.
[0037] In addition, in one embodiment of the present invention, the surface layer in (D) is integrated with the base layer formed in (C) by bonding, thereby increasing the durability of the road pavement substructure and reducing the thickness of the surface layer.
[0038] In addition, in one embodiment of the present invention, the soil mixture obtained in (B) in (C) is laid on the compacted roadbed to form a base layer using an asphalt finisher.
[0039] In addition, in one embodiment of the present invention, the toughness reinforcing agent powder in (C) is characterized by using a powder obtained by crushing industrial by-products including incineration ash, waste gypsum, and waste lime generated from an incineration facility and waste glass fibers generated during the glass fiber manufacturing process, and mixing them with fine powder of blast furnace slag.
[0040] In addition, in one embodiment of the present invention, the durability reinforcing agent powder in (C) is characterized by using a surface-treated silica aerogel.
[0041] The features and advantages of the eco-friendly paving method according to the present invention, which utilizes on-site soil to achieve excellent carbon emission reduction and ensure strength, are described in detail as follows.
[0042] 1. First of all, since a large amount of external aggregate is not brought in for base layer construction, the cost and time associated with the supply of aggregate can be reduced. Also, since the soil and sand at the site are used as is, there is no need for costs such as quarry development, crushing, and transportation for aggregate supply, which can significantly reduce material costs and reduce carbon emissions resulting from aggregate extraction and production.
[0043] 2. In addition, since the subbase and base layer construction is completed by mixing the soil mixture (a mixture of the original ground soil, cement, and the raw material mixture (humers) according to the present invention) without proceeding with aggregate laying and compaction, the problem of the construction period (at least 14 to 28 days) due to curing, especially in the case of concrete base layers, can be solved. Furthermore, since the base layer is completed in as little as 1 day using the method according to the present invention, allowing for the laying of surface materials such as asphalt concrete, the construction period can be drastically shortened, thereby having the effect of reducing carbon emissions.
[0044] 3. In addition, since the base layer formed by the soil mixture and the surface layer such as asphalt concrete can be integrated, stability and durability are ensured, which allows for a reduction in the thickness of the surface layer such as asphalt concrete, thereby reducing construction costs. Furthermore, since the amount of surface layer material used can be reduced, there is also an effect of reducing carbon emissions generated during the production and transportation of surface layer materials.
[0045] 4. In addition, since the waste soil generated from excavation for base construction can be utilized as a base material by mixing it into a soil mixture on-site rather than incurring costs for disposal, there is an effect of doubling the reduction in construction costs. Furthermore, since the use of equipment such as dump trucks for waste disposal can be reduced, there is also an effect of reducing carbon emissions.
[0046] 5. In addition, since the hydration reaction time of cement and water can be controlled after mixing the soil mixture, a homogeneous mixture can be achieved with sufficient time, thereby improving workability and uniformity of quality. Furthermore, since it does not harden immediately after mixing, a uniform mixture can be achieved at the batch plant, allowing for the maintenance of consistent strength, which prevents construction defects caused by uneven settlement or problems with the base and sub-base layers after construction.
[0047] 6. In addition, since the amount of cement used can be drastically reduced, the occurrence of shrinkage cracks caused by the heat of hydration generated during cement hydration curing can be reduced, and stability can be ensured through the integration between the surface layer, such as asphalt concrete, and the base layer of the soil mixture, while also having the effect of reducing carbon emissions generated during the production and transportation of cement.
[0048] 7. In addition, since the required strength can be satisfied without using a large amount of cement as in conventional construction methods, and durability and internal toughness can be strengthened, carbon emissions from cement production can be reduced and stability can be improved, and since the thickness of the surface layer can be reduced by up to 50%, there is an additional effect of reducing carbon emissions from the production, transportation, and laying of surface materials such as asphalt concrete.
[0049] Figure 1 is a drawing showing a comparison between a conventional asphalt road design cross-section and a road design cross-section according to the present invention.
[0050] The following describes specific details for implementing the present invention.
[0051]
[0052] The eco-friendly paving construction method according to the present invention
[0053] (A) A first step of obtaining a raw material mixture by mixing 10~30 wt% sodium chloride, 10~25 wt% calcium chloride monohydrate, 10~25 wt% calcium chloride, 5~10 wt% sodium triphosphate, 5~10 wt% sodium sulfate, 2~5 wt% sodium lignosulfonate, 3~6 wt% sodium bicarbonate, 1~3 wt% aluminum sulfate, 1~3 wt% calcium carbonate, and 1~3 wt% calcium superphosphate;
[0054] (B) A second step of obtaining a soil mixture by mixing 100 parts by weight of original ground soil and 5 to 8 parts by weight of cement, and further mixing a solution obtained by dissolving 0.2 to 0.3 parts by weight of the raw material mixture obtained in (A) in water;
[0055] (C) A third step of forming a subbase and a base layer by further mixing 0.01 to 1.0 parts by weight of toughness reinforcing agent powder and 0.01 to 3.0 parts by weight of durability reinforcing agent powder based on 100 parts by weight of the soil mixture obtained in (B) above, laying it on a compacted roadbed, and compacting it with a roller; and
[0056] (D) A fourth step of forming a surface layer by laying a surface layer material on the sub-base layer and base layer formed in (C) above and compacting it with a roller; characterized by comprising
[0057]
[0058] In the present invention, the above-described eco-friendly paving construction method is a construction method that stabilizes the ground using a raw material mixture called Humus (HUMUS B). In the present invention, such a construction method is named the HSSM Method (Humus Soil Stabilization Method). The HSSM Method will be described in detail below.
[0059]
[0060] First, in the present invention, the raw material mixture is composed of a mixture of inorganic salts in powder form, and specifically, it is composed of a composition comprising 10 to 30 weight% sodium chloride, 10 to 25 weight% calcium chloride monohydrate, 10 to 25 weight% calcium chloride, 5 to 10 weight% sodium triphosphate, 5 to 10 weight% sodium sulfate, 2 to 5 weight% sodium lignosulfonate, 3 to 6 weight% sodium bicarbonate, 1 to 3 weight% aluminum sulfate, 1 to 3 weight% calcium carbonate, and 1 to 3 weight% calcium superphosphate.
[0061] In the present invention, the sodium chloride acts to induce early hardening by promoting the formation of sulfate salts in the mixed soil, and it is preferable that the usage range be 10 to 30 weight percent.
[0062] In addition, in the present invention, the calcium chloride monohydrate is a component formed by combining water with calcium chloride, and is a substance obtained by combining calcium chloride and water in a molar (Mol) ratio of 1:1. The calcium chloride monohydrate serves to regulate moisture content to an appropriate level, and in the present invention, it is preferable that the usage range be 10 to 25 weight percent.
[0063] In addition, in the present invention, calcium chloride promotes an exothermic reaction to induce a hydration reaction, and it is preferable that the usage range be 10 to 25 weight percent.
[0064] In addition, in the present invention, sodium triphosphate acts to disperse aggregated soil fine particles and strengthen the solidification with cement, and it is preferable that the usage range be 5 to 10 weight percent.
[0065] In addition, in the present invention, sodium sulfate plays a role in densifying the tissue by promoting a sulfidation reaction, and it is preferable that the usage range be 5 to 10 weight percent.
[0066] In the present invention, sodium lignosulfonate plays a role in enhancing dispersibility and cohesion with soil by surrounding cement particles with an absorbent film, and maintains water retention to aggregate soil fine particles such as clay, thereby maintaining long-term stability through water retention. In the present invention, it is preferable that sodium lignosulfonate be included in an amount of 2 to 5 weight percent.
[0067] In addition, in the present invention, sodium bicarbonate plays a role in densifying the tissue, and it is preferable that the usage range be 3 to 6 weight percent.
[0068] In the present invention, aluminum sulfate plays a role in promoting solidification and enhancing stiffness by inducing aluminum ions to ionicly bond with (-) groups on the soil surface and anions to ionicly bond with (+) groups on the cement surface through an ion exchange reaction. In the present invention, it is preferable that the aluminum sulfate be included in an amount of 1 to 3 weight percent.
[0069] In addition, in the present invention, calcium carbonate plays a role in promoting soil solidification and preventing shrinkage, and it is preferable that the usage range be 1 to 3 weight percent.
[0070] In addition, in the present invention, calcium superphosphate reacts with cement to form ettringite, thereby densifying the structure and contributing to strength development, and it is preferable that the usage range be 1 to 3 weight percent.
[0071] The components used in the raw material mixture according to the present invention are all components that are highly soluble in water and have good dispersibility in water, and are environmentally friendly as they do not generate byproducts of heavy metals or other harmful substances.
[0072] The present invention consists of salts that are easily soluble in water, and multiple cations ionically bond with anions charged on the surface of the soil, and the anions ionically bond with cations charged on the surface of the cement, thereby acting as a mediator of bonding between soil particles and cement particles. In addition, due to the characteristics of each component, hydration, solidification, and water absorption are promoted, thereby enabling the solidification effect to manifest early and increasing strength.
[0073] In the present invention, the raw material mixture obtained from the above composition is referred to by the product name "HUMUS B" for convenience of explanation and is abbreviated as "HUMUS." Additionally, the mixture of the raw material mixture obtained above and the original ground soil and cement to be described below is referred to as the "soil mixture" or "HUMUS mixture" in the description.
[0074] In the present invention, the raw material mixture (humus) is mixed with cement and soil to form a soil mixture. Since the type of cement is not limited, general Portland cement, slag cement, rapid-hardening cement, etc., may be used alone or in combination.
[0075] The components included in the soil mixture according to the present invention are composed of 100 parts by weight of original ground soil, 5 to 8 parts by weight of cement, and 0.2 to 0.3 parts by weight of the raw material mixture (humus) obtained in (A).
[0076] The cement particles within the aforementioned soil mixture have activated surfaces that generate bubbles and adsorb fine soil particles, thereby enhancing cohesion. Additionally, as the hydration reaction of the cement proceeds, the surfaces expand and become evenly distributed within the base layer.
[0077] The soil mixture according to the present invention is used as a base material by mixing the soil (soil) in an appropriate amount according to the moisture content and target compressive strength of the soil, and by mixing in an appropriate amount of water. In particular, in the present invention, soil (soil) discharged from the site can be used as is.
[0078] In the present invention, it is preferable to use a mixture of 5 to 8 parts by weight of cement and 0.2 to 0.3 parts by weight of the raw material mixture (humus) based on 100 parts by weight of soil, such as original ground soil having a moisture content of, for example, 10 to 18 weight%.
[0079] In the present invention, the soil may be sand generated during excavation of roads, etc., sand generated at construction sites of apartments, parking lots, general roads, or industrial roads, or other on-site soil distributed in wetlands, riversides, etc. For example, clay, silt, or peat with non-uniform particle size and compressibility may be used, and soil from desert regions may also be used.
[0080] Meanwhile, in conventional soil cement methods, when constructing base layers using on-site soil, ordinary Portland cement, or slag cement, the hydration reaction is hindered by organic matter in the soil; furthermore, if a large amount of cement is used to resolve this, cracks occur due to drying shrinkage.
[0081] To solve these problems and use the on-site soil as is, the present invention utilizes a soil mixture (humus mixture) in which a raw material mixture consisting mainly of metal salts is mixed with cement and soil to induce bonding between the soil and cement, and to promote solidification and the development of high strength by facilitating the hydration reaction and water absorption.
[0082] In preparing a soil mixture (humus mixture) containing on-site soil according to the present invention, on-site soil is first collected and only stones or gravel of a certain size or larger (diameter greater than 40 mm) are filtered out, and then placed in a batch mixer (e.g., a mobile batch plant) and mixed with cement and the raw material mixture in an appropriate ratio. At this time, the mixing ratio may vary depending on the required physical properties, but it is preferable to mix 5 to 8 parts by weight of cement and 0.2 to 0.3 parts by weight of the raw material mixture (humus) based on 100 parts by weight of the on-site soil. At this time, depending on the condition of the on-site soil, the process of filtering out stones of a certain size or larger may be omitted, and the on-site soil may be used as is.
[0083] Water meeting the compaction requirements (90~95%) can be mixed into the soil mixture (humus mixture) prepared in this way, and it can be used as is for base layer construction.
[0084] Conventional soil cement begins to harden immediately upon mixing with water, so the time for laying and compaction work is limited to a maximum of 2 hours, and in countries that use soil cement, such as the United States, these standards are specified in the specifications. Consequently, due to time constraints regarding soil mixing and construction, sufficient mixing is not achieved, and there are areas where the solidification material is not mixed locally. This results in uneven strength development, which may lead to defects such as differential settlement and cracking after construction due to poor construction and material quality.
[0085] However, the soil mixture (humus mixture) obtained according to the present invention can be maintained in a gel state for a certain period of time without the hydration reaction occurring immediately even when mixed with water. In the present invention, the time during which the gel state can be maintained is 6 to 24 hours after mixing, and since hardening due to the hydration reaction does not occur while maintaining the gel state, sufficient time for construction can be secured (compaction work can be performed within 4 to 24 hours after mixing the humus mixture), and since the mixing can be carried out uniformly and sufficiently, construction defects such as uneven settlement and cracking, which are common with conventional solidification materials, can be prevented.
[0086] In addition, the third step of (C) in the present invention is characterized by further mixing 0.01 to 1.0 parts by weight of toughness reinforcing agent powder and 0.01 to 3.0 parts by weight of durability reinforcing agent powder based on 100 parts by weight of the soil mixture obtained above.
[0087] In the present invention, the toughness reinforcing agent powder is characterized by using a powder obtained by crushing industrial by-products including incineration ash, waste gypsum, and waste lime generated from an incineration facility, and waste glass fibers generated during the glass fiber manufacturing process, and mixing them with fine powder of blast furnace slag.
[0088] Specifically, the toughness reinforcing agent powder may be obtained by mixing 100 parts by weight of an industrial byproduct consisting of one or more types selected from the group including incineration ash, waste gypsum, and waste lime generated from an incineration facility with 1 to 100 parts by weight of waste glass fiber generated during the glass fiber manufacturing process, grinding the mixture using a fine grinding device to form a powder, and then mixing 1 to 50 parts by weight of the obtained powder based on 100 parts by weight of fine blast furnace slag powder.
[0089] In the present invention, the toughness reinforcing powder plays a role in improving the safety of the base layer by increasing the tensile strength and enhancing the shear resistance in the humus mixture.
[0090] In addition, the durability reinforcing agent powder in the present invention is characterized by using surface-treated silica aerogel.
[0091] In the present invention, there was a possibility that the durability of the humus mixture could weaken over time, but in the present invention, this problem can be solved by mixing a specially pretreated silica aerogel before compaction.
[0092] In particular, the above silica aerogel had a problem in that it was difficult to mix and disperse, so it could not exhibit uniform performance. However, in the present invention, this problem can be solved by pre-treating the surface of the silica aerogel with hydrogen ions using reducing water, which makes it easy to mix with the humus mixture and enables uniform dispersion, thereby improving overall performance.
[0093] In the present invention, pre-treating the silica aerogel is
[0094] (a) A first step of obtaining reduced water by supplying an electrolyte mixture to an electrolysis module and applying a potential in the form of a constant current;
[0095] (b) A second step of wetting and dispersing silica aerogel by adding the reduced water obtained above under stirring;
[0096] (c) A third step of removing impurities generated during the solvent exchange and electrolysis processes from the liquid obtained above through filtering, diluting, and then ultrasonically treating; and
[0097] (d) A fourth step of drying the liquid obtained in (c) above; the process may be carried out by including the above step.
[0098] Reduced water is produced by supplying an electrolyte mixture to the cathode of the above electrolysis module at a rate of 100 to 800 (ml / min) and applying a potential of 3 to 30 (v) (2 to 10 (A)) in the form of a constant current.
[0099] It is preferable to use reduced water produced by this process that has an ORP (Oxidation-Reduction Potential) of -500mV or less.
[0100] Next, surface treatment of the silica aerogel is performed using the reduced water obtained above.
[0101] Specifically, the above-mentioned reduced water is stirred with a homogenizer (3,000 to 10,000 RPM) or an agitator, and then silica aerogel is slowly added in a weight ratio of 1 to 20 relative to 100 weight of reduced water to wet and first disperse it.
[0102] Next, the above-mentioned aged liquid is filtered to remove impurities generated by solvent substitution and electrolysis processes, and then used.
[0103] Next, the liquid obtained above is diluted to 10 to 30 weight percent and ultrasonically treated using ultrasound (750 watts (20 kHz)) at a rate of about 1 liter / 10 min.
[0104] Subsequently, the liquid obtained from the above process is vacuum filtered and dried to obtain a surface-pretreated silica aerogel. At this time, it is preferable that the moisture content of the silica aerogel be 0 to 30 weight%.
[0105] The silica aerogel obtained through this process has hydrogen ions adsorbed on its surface and pores, which facilitates mixing with other components, particularly inorganic salt components, during the mixing and dispersion process with the humus mixture; consequently, it becomes possible to secure overall uniform performance.
[0106] Due to these characteristics, the inherent properties of silica aerogel, namely the durability enhancement effect, can be fully realized.
[0107]
[0108] The present invention involves laying the gel-state humus mixture compaction material obtained as described above using an asphalt finisher and compacting it using a roller, etc. Through this compaction process, the humus dissolved in water begins to harden through hydration and ionic bonding reactions between the on-site soil and cement, thereby completing the hardening process in a short period of time.
[0109] In the present invention, it is presumed that the hardening between materials during the compaction process is promoted because the discharge of water accelerates the ionic bonding reaction between the raw material mixtures, thereby forming a three-dimensional network structure with silicon compounds in the soil.
[0110] Specifically, first, a roadbed is constructed by cutting or filling to the depth of the subbase layer for road construction. In the present invention, a single base layer is formed by laying and compacting a humus mixture, and a surface layer such as asphalt concrete is laid on top thereof. By integrating the base layer made of the humus mixture with the surface layer such as asphalt concrete, a rigid road substructure can be formed, and accordingly, the thickness of the road cross-section can be reduced.
[0111] After excavation work, the ground is leveled and the original ground soil obtained from the site (soil from which stones or gravel of excessive size (diameter exceeding 40 mm) have been removed) is mixed with cement and the above-mentioned raw material mixture (humers) to form a soil mixture (humers mixture). The soil mixture (humers mixture) thus formed is then mixed with an appropriate amount of water, laid, and compacted. At this time, to ensure homogeneous laying and the formation of a design gradient, an asphalt finisher or the like is used for laying, and compaction can be performed by rolling with a roller.
[0112] Next, after the compaction is completed, the compacted soil mixture is cured. In the present invention, the curing is typically completed within 1 to 3 days (24 to 72 hours), or at most 3 days, under ambient temperature conditions, specifically at about 10 to 50°C, so it can be drastically shortened compared to the curing time of the existing base layer concrete (about 14 to 28 days or more).
[0113] In the present invention, the base layer formed by curing the humus mixture allows for vehicle traffic immediately after compaction, and asphalt surface paving becomes possible after about one day has passed since laying.
[0114] In the present invention, a base layer is formed by laying a humus mixture in the manner described above, and then a surface layer, such as asphalt concrete, is laid on top of it to form a surface layer.
[0115] At this time, the surface layer can be integrated with the formed base layer to further strengthen its strength, while simultaneously drastically reducing the thickness of the surface layer, such as asphalt concrete, being laid. At this time, if a tack coating is applied between the base layer and the surface layer, water-blocking and waterproofing functions can be improved.
[0116] The tack coating used in the present invention may use slow-curing or rapid-curing emulsified asphalt, other latex-based asphalts, and other tack coatings commonly used in the technology to which the present invention belongs may be utilized without limitation.
[0117] Figure 1 is a drawing showing a comparison between a conventional asphalt road design cross-section and a road design cross-section according to the present invention.
[0118] As shown in FIG. 1, the road design cross-section according to the present invention is composed solely of a base layer without an auxiliary base layer, and the thickness of the base layer can be drastically reduced compared to the combined thickness of the existing auxiliary base layer (20–40 cm) and base layer (10–25 cm) (approx. 15–40 cm).
[0119] In addition, the thickness of the surface layer, such as asphalt concrete, formed on the base layer can be drastically reduced by 20–50% to 5–12 cm compared to the existing thickness of about 10–15 cm. By doing so, the amount of cement used in the base layer and the amount of materials such as asphalt concrete used in the surface layer can be reduced, thereby preventing soil contamination and making it eco-friendly. Furthermore, economic efficiency can be improved through material savings, and carbon emissions can be reduced.
[0120] In addition, since the amount of cement used when forming the base layer can be significantly reduced compared to conventional materials, shrinkage cracks caused by the action of cement can be minimized, which has the advantage of allowing construction without joint work when laying the humerus mixture.
[0121] In addition, the strength of the humus mixture base layer material obtained according to the present invention is about 2.0 to 5.0 MPa, which meets the road base layer strength standards of various countries around the world, and thus it is possible to secure sufficient strength as a road base layer.
[0122] The paving construction method and paving structure according to the present invention have been described in detail above with reference to the attached drawings. The present invention is an eco-friendly paving method utilizing on-site soil. By utilizing excavated soil generated at the construction site directly for compaction construction without the need to produce aggregates required for paving construction using separate equipment or methods, or to transport them over long distances using dump trucks, etc., it has the effect of effectively reducing the massive carbon emissions caused by diesel-fueled dump trucks and on-site equipment in conventional road construction.
[0123] Furthermore, the present invention provides an eco-friendly paving method that not only contributes to achieving Korea's NDC targets through such carbon emission reduction technology, but also allows the reduction results generated from greenhouse gas reduction projects through climate change cooperation with developing countries to be reflected in the NDC performance of both countries through corresponding adjustments.
[0124] Furthermore, the present invention supports the achievement of additional carbon reduction targets by converting reduction achievements into internationally tradable carbon credits through voluntary participation in the carbon market, and based on this, can provide a technical foundation for revitalizing the global carbon market and promoting carbon reduction activities in the private sector.
[0125] The embodiments of the present invention described above are merely illustrative, and those skilled in the art will readily understand that various modifications and equivalent alternative embodiments are possible therefrom. Therefore, it will be understood that the present invention is not limited only to the forms mentioned in the detailed description above. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims. Furthermore, the present invention should be understood to include all modifications, equivalents, and substitutions within the spirit and scope of the present invention as defined by the appended claims.
Claims
1. (A) A first step of obtaining a raw material mixture by mixing 10~30 wt% sodium chloride, 10~25 wt% calcium chloride monohydrate, 10~25 wt% calcium chloride, 5~10 wt% sodium triphosphate, 5~10 wt% sodium sulfate, 2~5 wt% sodium lignosulfonate, 3~6 wt% sodium bicarbonate, 1~3 wt% aluminum sulfate, 1~3 wt% calcium carbonate, and 1~3 wt% calcium superphosphate; (B) A second step of obtaining a soil mixture by mixing 100 parts by weight of original ground soil and 5 to 8 parts by weight of cement, and further mixing a solution obtained by dissolving 0.2 to 0.3 parts by weight of the raw material mixture obtained in (A) in water; (C) A third step of forming a subbase and a base layer by further mixing 0.01 to 1.0 parts by weight of toughness reinforcing agent powder and 0.01 to 3.0 parts by weight of durability reinforcing agent powder based on 100 parts by weight of the soil mixture obtained in (B) above, laying it on a compacted roadbed, and compacting it with a roller; and (D) A fourth step of forming a surface layer by laying a surface layer material on the sub-base layer and base layer formed in (C) above and compacting it with a roller; characterized by comprising an eco-friendly paving construction method.
2. An eco-friendly paving construction method according to Claim 1, wherein the original ground soil in (B) is soil extracted from the original ground that has been cut or excavated, or excavated soil generated at a construction site of an apartment, parking lot, general road, or industrial road with a diameter of 40 mm or less, which is separated and used as is without separation.
3. An eco-friendly paving construction method according to Claim 1, characterized in that, in (B), the soil mixture is performed in such a way that the hydration reaction with cement is suppressed for 6 to 24 hours after mixing, thereby securing the mixing time and enabling the securing of homogeneous quality.
4. An eco-friendly paving construction method according to Claim 1, wherein the surface layer in (D) is integrated with the base layer formed in (C) by bonding, thereby increasing the durability of the road pavement substructure and reducing the thickness of the surface layer.
5. An eco-friendly paving construction method according to Claim 1, characterized in that the soil mixture obtained in (B) in (C) is laid using an asphalt finisher to form a base layer on a compacted roadbed.
6. An eco-friendly paving construction method according to Claim 1, wherein the toughness reinforcing agent powder in (C) is obtained by crushing industrial by-products including incineration ash, waste gypsum, and waste lime generated from an incineration facility and waste glass fibers generated during the glass fiber manufacturing process, and mixing them with fine powder of blast furnace slag.
7. An eco-friendly paving construction method according to claim 1, wherein the durability reinforcing agent powder in (C) above is surface-treated silica aerogel.