• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.852-857
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• 2009

Recently the centrifuge test has been used increasingly to clarify a problem of seepage in dam. However, one of the most difficult challenges in the testing is to conform permeability properties of model ground to the prototype. In order to resolve the problem, a few solutions, such as an increase of pore water viscosity and a regulation of water permeability, are suggested. Although the use of prototype materials is principles if a model test is carried out, the materials of similarity gradation is used in the centrifuge model test because of the nature of the model test for dam. Therefore, we choose the latter method for model ground materials. In this study, the permeability properties of soil-bentonite mixtures are studied through the permeation test using triaxial compaction test apparatus.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.64-69
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• 2001

This study is the fundamental report to propose the capability of discarded Bentonite by heat-treatment as concrete mineral admixture. The experiment is performed by flow test of mortar and by compressive strength of 7, 14, 28, 91 days, As a result of experiment about mortar using discarded Bentonite by heat-treatment, in the case of $500^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$, $800^{\circ}C$.60min, compressive strength is superior to the every situation than plain Mortar. Especially, in the case of $700^{\circ}C$.60min, as strength activity index is measured by 109%, it can be applied as concrete mineral admixture. But, flow of Mortar using discarded Bentonite by heat-treatment is decreased about 2.5cm in the case of 30min and about 1.7cm in the case of 60min.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.2
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• pp.1-9
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• 2019

In a ground-source heat pump (GSHP) system, a vertical ground heat exchanger (GHE) is widely accepted due to a higher thermal performance. In the vertical GHE, grout (also called grouting material) plays an important role in the heat transfer performance and the initial installation cost of the GHE. Bentonite-based grout has been used in practice because of its high swelling potential and low hydraulic conductivity. This study evaluated the thermo-physical properties of the bentonite-based grouts through lab-scale measurements. In addition, we conducted performance simulation to analyze the effect of mixed ratio of grouts on the design length and thermal performance of the vertical GHE. The simulation results show that thermally-enhanced grouts improve the heat transfer performance of the vertical GHE and thus reduce the design length of GHE pipe.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.10a
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• pp.343-350
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• 1998

• Proceedings of the Korean Geotechical Society Conference
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• 1998.10a
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• pp.97-104
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• 1998

• Environmental Engineering Research
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• v.7 no.4
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• pp.219-225
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• 2002

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.2
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• pp.99-112
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• 2015

In this study, laboratory test equipment was designed and installed to evaluate the thermal behavior of bentonite, which is used as a buffer in high-level waste disposal systems. The thermal analysis was conducted to verify the test results using ABAQUS, a finite element analysis code. In view of the seasonal changes seen during the test, the thermal behavior of bentonite with a temperature of outside air was evaluated. Of the cases examined, the results of the analysis model using stainless steel (Case 3) approximates to the test results, showing an error of about 1℃. The results of the thermal analysis into seasonal temperature distributions are consistent with trends seen in lab-test results. These analyses show that the effects of the thermal conductivity of the material surrounding the buffer and outside air temperature, are very important factors in the thermal behavior of bentonite. In the future, it is expected that a moisture saturation test of a bentonite buffer containing a heat source will be carried out. Therefore, the development of a numerical analysis model is required for the prediction and verification of the laboratory test results.

• Journal of Korea Soil Environment Society
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• v.5 no.2
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• pp.33-43
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• 2000

Mining wastes left without any proper treatment are affecting barren or arable lands where are located near and far from source through various pathway Metals are the only hazardous constituents that cannot be destroyed or altered by chemical or thermal methods and must be converted into the most insoluble and harmless form as possible, which have slower leaching rates than the original species, to prevent their reentry into the environment. Three types of chemical additives used in this study to immobilize heavy metals showed high immobilized capacity (q) and the efficiency (k) in the order of CaO, $Na_2$S.$5H_2$O, and $CaCO_3$. In addition, bentonite was considered as a good additive to remedy AM(Acid Mine Drainage) from the results of the physicochemical characteristics and immobilizing capacity. The Freundlich coefficients (n and k) from adsorption isotherm for the heavy metals adsorbed on 50g Benlonite were calculated.

• Economic and Environmental Geology
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• v.33 no.1
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• pp.31-40
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• 2000

Sorption characteristics of Pb, Cu, Cd, and Zn onto Ca- and Na-bentonites were investigated by the batch experiments in the condition of various pHs and concentrations of groundwater major anions (${So_4}^{2-}$ and ($HCO_3$), which can form a complex with heavy metals. The sorption removal of heavy metals steadily increases as pH increases. The sorption capability about heavy metals of both Ca-bentonite and Na-bentonite is in the order of Pb>Cu>Zn>Cd. The effect of pH and selectivity of heavy metals of bentonites were explained by the change of surface charge of bentonite and the speciation of heavy metals. Na-bentonite has a little higher sorption ability about heavy metals than that of Ca-bentonite. A high sorption removal of Pb in 0.1M sulfate solution may be attributed to the precipitation of $PbSo_4$(anglesite). However, sulfate has a slight effect on the sorption of CU, Cd and Zn. More than 99% of heavy metals were removed from the 0.1 M bicarbonate solution. However, the efficiency of sorption removal of heavy metals highly decreases in the bicarbonate solution of $10^{-2}$M to $10^{-4}$M. The speciation and saturation index calculated by the WATEQ4F program indicate that the sorption of anionic complexes such as ${Pb(CO_3)_2}^{2-}$, ${Cd(CO_3)_2}^{2-}$, ${Zn(CO_3)_2}^{2-}$, ${Cu(CO_3)_2}^{2-}$ and the precipitation of the solid phases such as $PbCO_3$(cerrusite), $ZnCO_3$(smithsonite), $CdCO_3$(obtavite) are involved in sorption removal of heavy metals in bicarbonate solution. The sorption capability about heavy metals of bentonites in the presence of anions shows the following order: Pb>Cu Cd>Zn.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.773-786
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• 2018

In this paper, viscosity features of sealant (bentonite-cement slurry), which is used for umbrella arch method in tunnel, were studied. The sealant must secure optimal strength and capacity for the waterproof and stabilization of borehole as well as to satisfy groutability. In this study, the variation of viscosity was measured with different mixing processes. With an increase of initial mixing period with water and bentonite mixture, the required time for the rapid increase of viscosity of the sealant is shorten. With increase of mixing period, the possibility of swelling of bentonite will increases and this can lead increase of the viscosity of the mixture. In addition, the behaviors of sealant vary with a drastic increase of the viscosity: thixotropy and rheopexy. Furthermore, the bentonite/water mixing period influences on the bleeding features of the sealant. Further study is required to introduce the guideline, which can be applicable in the field in the aspect of required capacity of the sealants and mixing processes of the ingredients.