• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.836-843
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• 2009

The Water Glass grouting method has been applied frequently to impermeable grouting in practice. But there is raising problems which are durability decrease by passage time and environmentally adverse effect. So, Earth Natural Grouting method which uses micro cement is developed to overcomes the problems of the Water Glass grouting method. And it is displayed ground injection extent like Water Glass grouting method. For verifying impermeability of ENG, it is carried out a triaxial permeability test about manufacturing specimen of ENG, SGR method which is a presentative Water Glass grouting method. Although Coefficient of permeability, k, of SGR is measured a little high than k of ENG whose value is $a{\times}10^{-6}cm/sec$, the value of ENG belong to impermeable rage. And, k of SGR shows relatively rapid increase according to cure time due to durability decrease of water glass. Also, in-situ test result of ENG has similar value with SGR method for similar ground.

• Korean Journal of Human Ecology
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• v.24 no.2
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• pp.285-295
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• 2015

To identify optimized thermal properties of mold brassiere cup for improved thermal comfort during summer, we compared the thermal resistance and the water vapor permeability of Polyurethane (PU) foam, 3D spacer fabric and the two combined materials of the PU foam and the 3D spacer fabric. Four experimental mold brassieres were made of the materials for wearing test. Six women in their twenties evaluated the wearing sensation in the hot and humid environment. The changes in microclimate temperature and humidity while wearing test brassiere cups were measured. Results indicate that thermal resistance increased as more PU foam were combined, while the water vapor permeability was higher as the content of the 3D spacer fabric increased at thickness of 18mm and over. However, in the wear test, the PU foam brassiere was the most preferred in all ambient conditions due to its soft, flexible and smooth texture, despite its high thermal resistance and low water vapor permeability. This indicates that the textures of mold foams are more dominant properties than thermal properties for mold foams in determining the wear comfort of mold brassieres.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.31-32
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• 2018

Lately, cement mixed siliceous powder waterproofing coating has been used as a waterproofing material in the wet environment condition of an underground concrete structure. Underground is exposed to environmental influences such as pressure of ground water, pressure of soil. However, the quality standard for pressure (water pressure, earth pressure) is not specified in the specification of the cement mixed siliceous powder waterproofing coating. Therefore, in this study, the permeability test was carried out based on the assumption that the durability should be verified in consideration of the environmental aspects of the material in actual field. As a result of the test, the permeability was generated from the inorganic single type material, but it was caused by the sealing failure and the test error, and the permeability was not generated in most of the materials. The results of this study will be analyzed by reviewing the physical properties of the material, and the research direction will be resumed.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.185-188
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• 2006

During the carbonation process in concrete, the rate of carbonation depends on porosity and moisture content of the concrete. For underground reinforced concrete structures, the interior concrete surface may be exposed to carbonation and the exterior concrete surface exposed to moisture due to wet soil or underground water. In this study, the permeability coefficients in mortar partially carbonated is derived as a function of carbonation depth and porosity of mortar by applying the so-called micro pore structure formation model (MPSFM) which was developed for the modeling of early-aged concrete. The permeability coefficient obtained from the micro-level modeling of carbonated mortar is verified with the results of accelerated carbonation test and water penetration test in cement mortar.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.211-216
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• 2003

Coated bars are protecting reinforcing bars from corrosion and enhancing durabilities of reinforced concrete structures are tested to evaluate corrosion protection properties. Tests are performed based on the relevant standards of ACI and ASTM, such as chemical resistance, salt water spray, salt crack test and chloride permeability test with the main variable of the coating thickness. Three type materials are tested by Polyethylene, epoxy and bare bar. Test results show good chemical protection property and chloride permeability. Polyethylene coated bar is good coating material than any other materials.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.279-282
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• 2007

When ground disturbance takes place due to vertical drain construction through mandrel penetration, that affects excess pore water pressure dissipation time because of soft clay coefficient of permeability decreasing. Eventually, consolidation time is influenced. In this research, we measure process of excess pore water pressure dissipation before and after each other different shape's mandrel penetration through model test, and calculates range of smear zone, coefficient of permeability and horizontal coefficient of consolidation after model test. Using of test result, we grasp a degree of drainage ability drop resulting from vertical drain construction.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.439-448
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• 2001

A two-dimensional finite difference numerical model was developed in order to simulate two-phase fluid flow in a single fracture. In the model, variation of viscosity with pressure and that of relative permeability with water saturation can be treated. For the numerical solution, IMPES method was used, from which the pressure and the saturation of water and gas were computed one by one. Seven cases of model test using parallel plates for a single fracture were performed in order to obtain the characteristic equation of relative permeability which would be used in the numerical model. it was difficult to match the characteristic curves of relative permeability from the model tests with the existing emperical equations, consequently a logistic equation was proposed. As the equation is composed of the parameters involving aperture size, it can be applied to any fracture.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.271-278
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• 1999

Soil filters are commonly used to protect the soil structures from eroding and piping. When filters are clogged by fine particles which are progressively accumulated, these may lead to buildup of excessive pore pressures also leading to instability in subsurface infrastructure. A filter in the backfill of a retaining wall, a filter adjacent to the lining of a tunnel, or a filter in the bottom of an earth dam can be clogged by transported fine particles. This causes reduction in the permeability, which in turn may lead to intolerable decreases in their drainage capacity. In this thesis, the extent of this reduction is addressed using results from both experimental and theoretical investigations. In the experimental phase, the permeability reduction of a filter is monitored when an influent of constant concentration flows into the filter (uncoupled test), and when the water flow through the soil-filter system to simulate an in-situ condition (coupled test), respectively. The results of coupled and uncoupled test are compared with among others. In the theoretical phase of the investigation, a representative elemental volume of the soil filter was modeled as an ensemble of capillary tubes and the permeability reduction due to physical clogging was simulated using basic principles of flow in cylindrical tubes. In general, it was found that the permeability was reduced by at least one order of magnitude, and that the results from the uncoupled test and theoretical investigations were in good agreement. It is observed that the amount of deposited particles of the coupled test matches fairly well with that of the uncoupled test, which indicates that the prediction of permeability reduction is possible by preforming the uncoupled test instead of the coupled test, and/or by utilizing the theoretical model.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.435-441
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• 2015

Concrete, as a porous media, has permeability and it is considered as a major parameter for durability evaluation. Cold joint caused by delayed placing of concrete accelerates water permeation and intrusion of harmful ions. In the paper, concrete specimens containing GGBFS (Ground Granulated Blast Furnace Slag) and OPC (Ordinary Portland Cement) are prepared with cold joint section, and water permeability and water flow at the age of 91 days are measured for 2 weeks. Sound concrete with GGBFS shows decreased permeability to 89% for sound concrete with OPC and 0.86 of decreasing ratio is evaluated in GGBFS concrete with cold joint. Through WPT (Water Penetration Test), the effects of mineral admixture and cold joint on water permeability are evaluated, and variation in water behavior via cold joint is analyzed through probabilistic method as well.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.393-398
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• 2005

In order to treat flow problems for an unsaturated soils, it is required the mediation of the coefficient of permeability with variation of suction. The coefficient of permeability for soils can be determined by the direct or indirect methods. The direct methods of permeability can be performed either in the laboratory or in the field. The indirect methods can be predicted from the soil-water characteristics curve. Laboratory test methods to measure the coefficient of permeability can be categorized into two types, steady-state and unsteady-state. In this study, the coefficient of permeability for unsaturated soils was determined by the modified apparatus for steady state-method(Klute, 1972) and was predicted from the equations of Brooks and Corey(1964) and Van Genuchten(1980). Experimental results were compared with predicted coefficient of permeability and verified applicability of the two equations.