STP1282: Characterization of Dielectric Constant on Fine-Grained Soil Behavior

    Kaya, A
    Graduate Research Assistant, Lehigh University, Bethlehem, PA

    Fang, H-Y
    Professor, Lehigh University, Bethlehem, PA

    Pages: 12    Published: Jan 1996


    Abstract

    It has been postulated in earlier studies that there is a considerable relationship between some engineering properties of fine-grained soils and the dielectric constant of pore fluid such as with hydraulic conductivity: the lower the dielectric constant, the higher the hydraulic conductivity. However, the mechanisms causing the increase in hydraulic conductivity are not understood well. It is the purpose of this paper to investigate some mechanisms that affect the fine-grained soil behaviors when the dielectric constant of pore fluid is changed. For this reason, the relationships between the dielectric constant of pore fluid and soil-fluid system properties for Atterberg limits, cation exchange capacity, and the zeta potential of kaolinite were determined with different organic solvents. It was observed that as the dielectric constant decreases, kaolinite's liquid limit increases whereas the plastic index remains almost constant. Furthermore, its zeta potential, which is an indication of the thickness of double layer, decreases. It was concluded that when the dielectric constant of pore fluid decreases the surface charge density of soil decreases which causes a higher flow area increasing the hydraulic conductivity.

    Keywords:

    fine-grained soil, hydraulic conductivity, Atterberg limits, cation exchange capacity, zeta potential, surface charge density, dielectric constant


    Paper ID: STP16580S

    Committee/Subcommittee: D34.09

    DOI: 10.1520/STP16580S


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