• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.87-88
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• 2010

A permeability of concrete is a very important factors evaluating durability. So, we are carrying out a lot of relational data bases and experiment regarding a permeability. In order to evaluate a permeability of concrete, we are proceeding study on the water penetration and diffusion in concrete by water pressure. Because a way to evaluate a permeability of concrete has a limit. We will present a good method of evaluating durability of concrete using the water penetration depth of concrete by water pressure. To carry this out, we executed experiment with penetration depth of concrete by water pressure and verified it though FEM analysis.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.39-46
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• 2000

This study is to investigate the watertightness properties of waterproofing admixture mixed redispersible polymer and siliceous powder. Series I deals with change in micro-structure of mortar by waterproofing admixture according to the water/cement ratios of 0.5, 0.6, 0.7 and 0.8 Crystal growth in micro-structure was observed through SEM to estimate on the watertightness effect of it. SeriesII deals with watertightness properties of waterproofing admixture on water permeability coefficient, crack restoration capacity and carbonation depth. SeriesII deals with watertightness properties of waterproofing admixture on water permeability coefficient, crack restoration capacity and carbonation depth. The result of this study can be summarized as follows. 1) Fluidity of mortar and concrete was increased by adding waterproofing admixture. 2) From observation through SEM. Crystals grew larger and denser in micro-structure as fiberic crystalization. 3) Waterproofing admixture is good watertightness properties in a level of high water/cement ratios and long limit of time. 4) Crack restoration capacity was appeared and durability was progressed by waterproofing admixture.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.111-118
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• 2008

The purpose of this paper was to investigate the overburden effect on soil-water characteristic curve and unsaturated permeability of unsaturated weathered soils. For this, unsaturated suction and permeability tests under various overburden stress were conducted respectively. Then, the coefficient of unsaturated permeability and moisture capacity of weathered soils were estimated and compared. All these results are presented in the paper.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.33-41
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• 2017

In this study, the increment effect of safety factor according to increasing of horizontal permeability coefficient is analyzed when geocell is installed on the slope for protection. To evaluate the horizontal permeability and reinforcement effect, the laboratory tests such horizontal permeability test were conducted. According to the laboratory test results, as the porosity rate of geocell increases, the coefficient of horizontal permeability is also increased. And also, regardless of the different types of filled materials, the coefficient of horizontal permeability is improved in a geocell reinforced ground compare with the non-reinforced ground. Laboratory test results and the rainfall intensity were applied to the numerical modeling of slope for seepage analysis and stability analysis of slope by using Soilworks, numerical analysis program. As a result of the slope stability analysis, it is confirmed that the installed geocell on the slope facilitates the drainage of water on the surface of slope. Hence, the ground water elevation is suppressed. Therefore, the safety factor of the slope is increased by the increasing of the internal friction angle, apparent cohesion, and coefficient of horizontal permeability by reinforcing the slope with geocell.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.414-418
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• 1998

This study was carried out to analyze permeability of steel slag. Three molds with the same grading of raw steel slag were used to measure the coefficient of permeability. Darcy's law could be applied to the steel slag below 0.5 of critical hydraulic gradient because the water flow changed from laminar flow to turbulent flow above the critical hydraulic gradient. Also, the velocity of flow changed according to hydraulic gradient. The coefficient of permeability of the specimen was $\alpha$$\times$10$^{-3}$ cm/ sec.

• Journal of the Korean Geotechnical Society
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• v.26 no.4
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• pp.15-26
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• 2010

To determine the frost heave suppressing mechanism of soil mixed with tire powder, we conducted three kinds of laboratory experiments: measurement of unfrozen water, evaluation of thermal conductivity, and a frost heave. In this research, we focused on changes in the coefficient of permeability of the mixed soil, and first found that of the unsaturated soil. Next, in the case of the presence of ice, we took the ice-impeding factor into consideration to derive the coefficient of permeability of the frozen fringe from the area ratio of the soil and tire powder in mixed soil. The results show a positive correlation between the water intake rate and the coefficient of permeability. Moreover, we found that the frost heave decreased thanks to a reduction in the permeability and a fall in the unfrozen water content of the soil mixed with tire powder. We also calculated the weight of the water content of the soil and tire powder void quantitatively using the result of the volumetric ratio of mixed soil.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.597-606
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• 2019

Due to climate change, coastal areas are being flooded with torrential rain, typhoons, and tsunamis. In addition, non-point source pollutants (NPSs) that accumulated on the ground, streets, and buildings during the dry season are washed off by rain and stormwater runoff, which adds to the damage associated with environmental pollution, e.g., pollution that makes its way into the ocean. Recently, low impact development (LID) has been considered as a means of controlling water circulation and NPSs. In the coastal area, permeable blocks have been constructed mainly to reduce the flood damage caused by waves. Some important design factors that must be considered to ensure long-term performance are the permeability coefficient, clogging, and the efficiency of the removal of total suspended solids (TSS), but currently there are no standardized design criteria or testing techniques that are used worldwide. Herein, we analyzed the permeability coefficient and the TSS removal efficiency tendency according to the permeability area ratio with an easily-detachable, permeable block filled with calcinated yellow soils as the filter media. Our lab-scale tests indicated that, when the permeability area ratio was 25%, the reduction of the permeability coefficient after clogged was 11%, which was a significant decrease compared to other cases. Permeability persistence increased when the permeability area ratio increased from 50% to 75%. The TSS removal efficiency decreased as the permeability area ratio increased. Our pilot-scale test indicated that the TSS removal efficiency was more than 80% higher in all cases. We also found that the permeability persistence was excellent as the permeability area ratio increased, and, in actual construction, it is effective to set 5.3% of the total area as permeable area in terms of permeability and economic feasibility.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.39-47
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• 2010

Using a conventional two-compartment cell with stirrers the separation of an aqueous solution of HCl-$NiCl_2$ by an anion-exchange membrane Neosepta-AFN was investigated. The dialysis process was characterized by the permeability coefficient of the membrane towards to $Cl^-$ ions. This quantity was determined by the numerical integration of equations, which describe the time dependence of the total concentration of $Cl^-$ ions in compartment initially filled with stripping agent (water), combined with an optimizing procedure. The analysis of the experimental results showed that this permeability coefficient is a satisfactory characteristic for the process studied. It can be graphically correlated with the initial acid and initial salt concentrations in the compartment initially filled with acid+salt mixture.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.635-640
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• 2001

In this study, a mathematical model is established for prediction of chloride penetration in unsaturated cracked early-age concrete. The model is combined with models for thermo-hygro dynamic coupling of cement hydration, moisture transport and micro-structure development. Chloride permeability and water permeability at cracked early-age concrete specimens are evaluated using a rapid chloride permeability test and a low-pressure water permeability test, respectively. Then, a homogenization technique is introduced into the model to determine equivalent diffusion coefficient and equivalent Permeation coefficient. Increased chloride transport due to cracks at the specimen could be predicted fairly well by characterizing the cracks using proposed model. Proposed model is verified by comparing diffusion analysis results with test results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.81-84
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• 2002

Recently Bentonite mat is applied various structure : External waterproofing for underground structure, A reclaimed land, Artificial lake, Large-scaled civil structure, etc. With these various structure environment, water quality for application of Bentonite Mat affects watertightness. Specially spot with a large quantity of Chloride ion like salt water, degree of watertightness revelation is evaluated and applied. In this study, it is a main goal to investigate watertightness of Bentonite Mat with distilled water and salt water dissolved chloride ion Contents 0.88%. The result of this paper is as follows. 1) Water permeability coefficient of Bentonite Mat : distilled water(1.21$\times$10$^{-9}$cm/sec), salt water(3.12$\times$10$^{-7}$cm/sec). 2) Variation of thickness : distilled water(187%), salt water(108%). 3) Swelling ratio : distilled water(1500%), salt water(350%).