• 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.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.39-46
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• 2019

Most of the soil used for reclamation is marine clay generated from dredging construction.The soft ground made of dredged clay has high water content and high compressibility, so the bearing capacity of the ground is very weak and it is difficult to enter the ground improvement equipment. Therefore, surface hardening treatment method is used to enter equipment prior to full-scale civil engineering work, and stabilizer is mainly used for cement series. Cement-based stabilizers have the advantage of improving the ground in a short period of time and have excellent economic efficiency, but they are disadvantageous in that they cause environmental problems due to leaching of heavy metals such as hexavalent chromium. In this study, environmental effects evaluation of dredged clay mixed with normal portland cement and environmentally friendly stabilizer was evaluated, and uniaxial compressive strength test and indoor model test were conducted to confirm the bearing capacity characteristics of the solidified layer.

• 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.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.79-85
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• 2005

An experimental study was carried out to investigate the recycling possibility of waste oyster shells, which induce environmental pollutions by piling up out at the open or the temporary reclamation. The purpose of this study is to develope eco-friendly binder using waste oyster shells, and to reinforce dredged soils fur soft soil improvement. In this paper, a series of laboratory tests including compressive strength tests were performed to evaluate strength characteristics of soils treated by developed binder with different water content of dredged soils, mixing rates of binder, curing days. Based on test results, eco-friendly binders manufactured from waste oyster shells were estimated as good resource materials for soft soil improvements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3923-3930
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• 2014

In this study, the physical and dynamic characteristics of soil were analyzed by selecting 3 sections as research subjects among road and structure construction sections in the construction site of the Gwangyang ${\bigcirc}{\bigcirc}$ industry area, and conducted consolidation analysis and bearing capacity assessments through Midas-GTS according to the construction conditions of the structures and section conditions of reinforcement using stabilized soil. The effects of improving the settlement and bearing capacity according to the improved effects of the stability and sections of reinforcement using stabilized soil in applying the reinforcement method using stabilized soil were analyzed as a solution for improving the settlement and bearing capacity of soft clay for constructing roads and structures. The improvement effects of the settlement and bearing capacity were outstanding when the reinforcement method using stabilized soil to the soft clay was applied. After applying the reinforcement method using stabilized soil, the holdback effect of the consolidation settlement was excellent by decreasing the volume of the consolidation settlement from a minimum of 53% to a maximum of 82%. When the width of the reinforcement using stabilized soil was twice the width of the constructed structure, it was found that the holdback effect of the consolidation settlement ranged from 1% to 7% through the width of reinforcement using stabilized soil. In addition, when applying reinforcement more than 6m in width and 1m in depth using stabilized soil, it was found that the increase in the allowable bearing capacity was 2.3 to 3.3 times more than that before applying the reinforcement, which suggests that the increase in bearing capacity by applying the reinforcement method using stabilized soil was significant.

• 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 $5.0kgf/cm^2$.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2001.06a
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• pp.7-7
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• 2001

다량의 점토 퇴적물로 구성된 연약지반은 대단히 큰 압축성과 낮은 강도, 높은 함수량등의 물리·역학적 특성을 갖는다. 이러한 기초지반으로서의 불리한 특성 때문에 이를 대상으로 하는 각종 토목건설공사에서는 지반개량이나 안정처리가 반드시 선행되어야 할 과제이다. 이를 위해 종래에는 샌드드레인, 페이퍼드레인 등의 물리적인 공법에 의한 지반개량이 주류를 이루었으나, 최근에는 생석회나 시멘트계 고화재를 이용한 화학적 안정 처리공법이 크게 주목을 받고 있어 이에 대한 연구가 활발한 상황이다. 본 연구는 연약 지반 안정처리에 대한 방안을 모색하기 위하여 김해 지역에 분포하는 점토 퇴적물을 대상으로 각종 광물재료를 이용한 반응실험을 통하여 반응생성물 조사와 압축강도시험 등을 행하여 그 결과를 검토하였다. 우선 연약지반의 고화에 이용 가능한 생석회, 석고, 플라이에쉬, 고분자폴리머, 시멘트 등을 사용하여 점토와 혼합한 고화실험을 행하였으며, 이에 대한 물성 및 반응생성물을 검토하였다. 이러한 각 재료를 점토에 혼합한 후 PVC관에 모울딩하여 양생시켜 실험하였다. 그 결과, 석고 및 소석회에 비하여 생석회의 경우가 비교적 큰 압축강도를 나타내고, 균열발생 빈도도 낮았다. 생석회의 경우에 Gehlenite, Hillebrandite 등의 생성물질이 검출되었다. 그러나 포틀란트 시멘트와 혼합한 경우가 강도가 가장 크게 나타났다. 반면에 고분자폴리머만 사용한 경우는 강도가 매우 낮았다. 따라서 시멘트를 일정 비율로 배합한 다른 재료를 첨가한 실험을 행하여 그 물성을 검토하였다 물질의 화학적인 특성을 고려하여 포졸란반응이 잘 일어날 수 있을 것으로 생각되는 여러 재료를 선정하여 많은 조합에 대한 실험을 행하였다. 생석회, 석고, 고령토, 규조토, 제올라이트 등의 여러 재료를 여러 조합으로 첨가하여 실험한 결과, 시멘트와 석고를 혼합한 것이 비교적으로 높은 압축강도를 나타내었다. 그리고 이러한 연구 결과를 바탕으로 연약점도의 고화에 최적인 조합과 배합비를 위한 실험을 재차 실시하였으며, 실험 후의 물성과 함께 반응생성물에 대한 검토도 행하여 그 결과를 발표하고자 한다.

• Journal of the Mineralogical Society of Korea
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• v.18 no.4 s.46
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• pp.301-312
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• 2005

The present study investigated the physical changes and reaction products with setting time after mixing of various mineral admixtures such as lime, hydrated lime, gypsum, kaolin, zeolite and diatomaceous earth with four types of cement (portland cement, slag cement, quick lime, hydrated lime) and clay rich sediments in soft foundation. As results, slag cement showed the greater compressive strength than normal portland cement. The mixing experiments with various mineral admixtures and slag cement resulted that gypsum showed the greatest compressive strength. Additionally, we conducted mixing experiments with various mixing ratios of gypsum and slag cement. The experiments showed that the mixing ratio of $30\%$ gypum and $70\%$ slag cement has the greatest compressive strength. Ettringite was produced as a reaction Product. This fact indicates that gypsum effectively promotes hydration reaction and contributed to the greater compressive strength. These experimental results can be used as fundamental data for the stabilization of soft clay foundation.

• 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.

• Geotechnical Engineering
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• v.29 no.7
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• pp.16-25
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• 2013