• Title/Summary/Keyword: 고화재

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Stabilizing Capability of Oyster Shell Binder for Soft Ground Treatment (표층/심층혼합처리용 굴패각 고화재의 고화성능 평가)

  • Yoon, Gil-Lim;Kim, Byung-Tak
    • Journal of the Korean Geotechnical Society
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    • v.22 no.11
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    • pp.143-149
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    • 2006
  • An experimental study was carried out to investigate the stabilizing capability of oyster shell binder, which was developed using waste oyster shell inducing environmental pollutions by piling up out at the open or the temporary reclamation. The purpose of this paper is to compare stabilinzing capability of oyster shell binder and cement binder with treated soils. For this, a series of compressive laboratory tests were peformed to evaluate strength characteristics of treated soils by both oyster shell binder and cement binder with varing water content of dredged soils, different mixing rates of binder and curing days. Based on test results, eco-friendly binder manufactured by oyster shells showed more stabilizing capacity than cement binder and is estimated as good resource materials for soft soil improvements.

Properties of Cementless Loess Mortar Using Eco-Friendly Hardening Agent (친환경 무기질 고화재를 사용한 무시멘트 황토모르타르의 특성)

  • Jung, Yong-Wook;Kim, Sung-Hyun;Lee, Dong-Gyu
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.3 no.4
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    • pp.355-365
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    • 2015
  • This study examined the fluidity and strength properties, water resistance, durability, and freeze-thaw of cementless loess mortar using an eco-friendly hardening agent. The experimental result indicates that 28 days compressive and flexural strength of the loess mortar was increased regardless of the weathered granite soil and loess mixture ratio as the replacement ratio of the hardening agent increases. The strengths were significantly increased until 14 days regardless of the hardening agent, while the effect on the strengths increasement was relatively low after 14 days. Thus, the strength development of loess mortar concrete was found to be faster than that of the normal concrete. In addition, when the hardening agent of 10% was used, the average flexural strength was 1.7MPa which is insufficient compared to the 28-day flexural strength of 4.5MPa for the paving concrete. However, the flexural strengths of the loess mortar concrete using the hardening agents of 20% and 30% were 4.0MPa and 5.3MPa, respectively. Thus, the hardening agent need to be at least 20% so that the loess mortar can be used for paving concrete. The experiment for water resistance shows that the repeated absorption and dry reduced mass regardless of the mixing ratio of the loess. The maximum length change also decreased with increasing the substitution rate loess mixture ratio and the hardening agent. The result of the freeze-thaw resistance test indicates that the relative dynamic modulus of elasticity at 300 cycle freeze-thaw with the hardening agents of 20% and 30% were 75% and 79%, relatively. Thus, the hardening agent of at least 20% is required to obtain the relative dynamic modulus of elasticity of 60% for the loess mortar.

소각재의 고온용융 고화처리 및 고화체 특성 분석 (I)

  • 김인태;김정국;양희철;이근우;김준형;구자공
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05c
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    • pp.485-490
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    • 1996
  • 가연성 폐기물의 소각후 발생되는 소각재는 처분 안전성을 높이기 위해 고화/안정화되어야한다. 본 연구에서는 유해폐기물 소각재를 대상으로 기본유리 구성물질을 첨가하여 고온용융에 의한 유리고화체를 제조하고 특성을 분석하여 유해 및 방사성 폐기물 소각재의 유리고화처리 가능성을 알아보았다. 실험결과 소각재를 유리고화할 경우 시멘트류의 저온 고화매질에 의한 처리방법에 비해 내용출특성 및 감용률이 상당히 향상되었으며 안정된 유리고화체가 형성되었음을 확인 할 수 있었다.

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Shear Strength Characteristics of Dredged Soil with Oyster Shell Binder (굴패각 고화재를 혼합한 준설토의 전단특성)

  • Lee, Sangjin;Yoon, Gillim;Lee, Yoongyu;Lee, Kidong;Kang, Ingyu;Kim, Hongtaek;Baek, Seungcheol
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.1
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    • pp.27-32
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    • 2007
  • Trafficability for construction equipments in soft ground should be secured by improving the surface course. For this situation, the ground improvement technique has been used with stiffening agent, but the improvement cement has been mostly used so far. However, oyster shell has been developed and used as the stiffening agent to expand the chance of recycling oyster shell, which is regarded as solid waste. In this research, it was confirmed mechanical characteristics of oyster shell as stiffening agent by analyzing the strength characteristic such as mixing rates, water contents, and curing days of that to the dredging soil.

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Development of Surface Pavement Materials for Environment-Friendly Farm Road (환경친화형 경작로를 위한 표층포장재료의 개발)

  • Sung, Chan-Yong;Kim, Young-Ik
    • Korean Journal of Agricultural Science
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    • v.31 no.2
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    • pp.105-114
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    • 2004
  • This study was performed to examine the physical and mechanical properties of eco-concrete using soil, natural coarse aggregate, soil compound and polypropylen fiber. The mass loss ratio was decreased with increasing the content of coarse aggregate and soil compound. The compressive strength, flexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity were increased with increasing the content of coarse aggregate, soil compound and polypropylene fiber. The compressive and flexural strengths were showed in 8.07 MPa and 2.641 MPa at the curing age 28 days, respectively. The coefficient of permeability was decreased with increasing the content of coarse aggregate and soil compound, but it was increased with increasing the content of polypropylene fiber. The lowest coefficent of permeability was showed in $5.066{\times}10^{-9}cm/s$.

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Development of Sulfated Oyster Shell-Based Solidifying Agent for Flowable Backfill Material (황산처리 굴패각을 이용한 유동성 뒷채움용 고화재 개발)

  • Wang, Xue;Kim, Sung Bae;Kim, Chang-Joon
    • Clean Technology
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    • v.24 no.4
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    • pp.315-322
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    • 2018
  • Industrial use of waste oyster shells is limited because of requiring excessive energy for converting natural oyster shells in the form of calcium carbonate ($CaCO_3$) into calcium oxide (CaO) for this purpose. This study aimed to develop energy-saving process for producing solidifying agent using waste oyster shells for backfill materials. It was suggested that oyster shells were converted to calcium sulfates which were mixed with sodium hydroxide solution and red clay, forming solid specimen. The optimal concentrations of sulfuric acid for sulfation of oyster shell and sodium hydroxide to generate calcium hydroxide ($Ca(OH)_2$), were determined. Unconfined compressive strength of solid specimen increased with increasing the content of solidifying agent while it increased also with increasing ratio of natural oyster shells to coal ash. The result clearly demonstrates that solidifying agent consisting of sulfuric acid-treated oyster shell, coal ash, and sodium hydroxide solution, can be effectively utilized for preparing backfill materials using natural oyster shell and coal ash. Sulfuric acid-treated oyster shell-based solidifying agent has not been previously developed and will contribute to broaden industrial application of waste oyster shells.

A Feasibility Study on the Deep Soil Mixing Barrier to Control Contaminated Groundwater (오염지하수의 확산방지를 위한 대체 혼합차수재의 적용에 관한 연구)

  • 김윤희;임동희;이재영
    • Journal of Soil and Groundwater Environment
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    • v.6 no.3
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    • pp.53-59
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    • 2001
  • There is a lot of method to manage the insanitary landfill but vertical cutoff walls have been widespreadly used and were installed into the subsurface to act as a barrier to horizontal groundwater flow, The stabilized material such as specialized cement or mixed soil with additives has been generally applied for the materials of the deep soil mixing barrier in korea. The amount of the stabilized material is dependent on the field conditions, because the mixing ratio of the material and the field soil should achieve a requirement in the coefficient of permeability, lower than 1.0$\times$$10^{7}$cm/sec. This study determined the quantity and optimized function ratio of the stabilized material in the formation process of the mixed barrier that was added with stabilized material on the field soil classified into SW-SC under USCS (Unified Soil Classification System). After that the fly ash and lime were selected as an additives an that could improve the function of the stabilized material and then the method to improve the functional progress in the usage of putting into the stabilized material as an appropriate ratio was studied and reviewed. The author used the flexible-wall permeameter for measuring the permeability and unconfined compressive strength tester for compressive strength, and in the view of environmental engineering the absorption test of heavy metals and leaching test regulated by Korean Waste Management Act were performed. As the results, the suitable mixing ratio of the stabilized material in the deep soil mixing barrier was determined as 13 percent. To make workability easy, the ratio of stabilized material and water was proven to be 1 : 1.5. With the results, the range of the portion of the additives(fly ash : lime= 70 : 30) was proven to be 20-40% for improving the function of the stabilized material, lowering of permeability. In heavy metal absorption assessment of the mixing barrier system with the additives, the result of heavy metal absorption was proved to be almost same with the case of the original stabilized material; high removal efficiency of heavy metals. In addition, the leaching concentration of heavy metals from the leaching test for the environmental hazard assessment showed lower than the regulated criteria.

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A Study on the Optimal Mixture Ratio for Stabilization of Surface Layer on Ultra-soft Marine Clay (초연약 해성점토의 표층고화처리를 위한 최적배합에 관한 연구)

  • 천병식;고경환;김진춘
    • Journal of the Korean Geotechnical Society
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    • v.18 no.4
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    • pp.33-43
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    • 2002
  • Recently, as large constructions on the coast increase, an application of a surface layer stabilization method which is one of the improvement methods for dredged soft clay has increased. However, there are few studies about this. The purpose of this study is clarifying characteristics of ultra-soft marine clay and hardening agent. Also, it is verifying an optimal mixture ratio of hardening agent through the laboratory tests according to designed experiments and proving by statistical analysis and pilot tests. Laboratory tests were performed with proper hardening agent and test soil in accordance with the design of experiments. Regression equations between hardening agents materials and unconfined compressive strength were derived from the tests. The applicability of regression equations were also verified by pilot tests. From the test results, it was found that hardening agent materials(cement, slag, fly-ash, inorganic salts, arwin, gypsum etc.) have some effect upon compressive strength. The optimal mixture ratio which satisfies the required compressive strength was derived from the statistical analysis. The effect of ground improvement by cements and hardening agents was confirmed through the pilot tests. This study will suggest data for design or construction criteria of stabilization of surface layer on ultra-soft marine clay.

Improvement Effectiveness of Soft Ground Using Hardening Agent (고화재 혼합처리를 이용한 연약지반개량효과)

  • Chun, Byung-Sik
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.2
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    • pp.59-64
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    • 2001
  • Recently, the application of shallow mixing method using hardening agent has increased because of the advantage of securing trafficability, reducing the working period, solving environmental problems caused by dumped and replaced soil, etc. In this paper, three types of representative hardening agents in Korea are used to achieve the optimum of ground improvement. 1he unconfined compression tests are carried out with specimens under various mixing ratios and curing periods of hardening agent to assess the stabilizing ability. The unconfined strengths on site were estimated with various mixing ratios based on the results of the laboratory tests. It was estimated that the improved strength on site was higher than that of the required strength $5.0kgf/cm^2$.

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Convergent Study on the Preparation of Sludge Modified Soils of Inorganic Consolidation Soil (무기계고화재의 슬러지 개량토 제조에 관한 융합연구)

  • Han, Doo Hee
    • Journal of the Korea Convergence Society
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    • v.8 no.2
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    • pp.157-162
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    • 2017
  • Inorganic stiffening agents were prepared by mixing paper sludge incineration ash, blast furnace slag fine powder quicklime, anhydrous gypsum and fly ash. The main components of the solidifying agent developed for sludge treatment were SiO, $Al_2O_3$, $TiO_2$, $Fe_2O_3$, $Mn_2O_3$, CaO, MgO, $Na_2O$, $K_2O$, $P_2O$, and $SO_3$. Unlike cement, the developed solidifying agent did not contain $Cr^{6+}$, which is known as a carcinogen. Heavy metals and oil contaminated soil were mixed with solidifying agent and cured for 7 days and the heavy metal content was below the environmental standard. Sewage sludge cake, food waste and solidifying agent were mixed with each other, and after 7 days curing, soil component test showed that the heavy metal content was below the environmental standard. After mixing the sludge, solidifying agent and additive mixture into the beaker, the ammonia concentration was measured to be 0 after 3 days.