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Title |
Simple Modeling to Estimate Water Permeability Coefficient of Cementitious Materials
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DOI |
https://doi.org/10.4334/JKCI.2019.31.2.165 |
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Keywords |
투수계수 ; 변색법 ; 염소 침투깊이 ; 모세관 공극수 ; YOON's 테스트 water permeability coefficient ; colorimetric indicator ; chloride penetration depth ; capillary pore water ; YOON's test |
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Abstract |
Permeability is the rate of fluid transport driven by a pressure gradient. Permeability coefficient is an important material parameter to estimate the durability of the pore structure of concrete. Unfortunately, it is difficult to directly measure the parameter. This study presents a practical and theoretical recipe for estimating the permeability coefficient of concrete. The type of liquid is known to be independent of the permeability coefficient. Thus, an experimental method was designed to measure the chloride penetration depth of concrete under artificial seawater pressure. Experiment of seawater penetration was accomplished with concrete under pressure and chloride penetration depth was measured by colorimetric indicator. Theoretical recipe was proposed, and the water permeability coefficient was back-calculated from the experimental data. The influence of pore water on water permeability coefficient was examined based on the three assumptions: case (a), volumetric fraction of capillary water is neglected, case (b), volumetric fraction of capillary water is independent of pressure, and case (c), capillary water is mixed with seawater that has penetrated into pores and the combined water penetrates due to pressure. It was found that the permeability coefficient for case (c) was higher than those of the other cases, and this coincided with the experimental data obtained by YOON's test.
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