Author(s): K. Badv; M. Mahmoudi
Linked Author(s):
Keywords: Moisture; Diffusion; Unsaturated; Silty-sand; Clay; Chloride
Abstract: Moisture and diffusion characteristics of silty-sand and clayey samples were studied using a Tempe-Diffusion Apparatus. The laboratory testing program included the soil mechanical index tests on soil samples, diffusion tests on high air entry ceramic disks in Tempe-Diffusion Apparatus, soil-water characteristic (SWC) tests on soil samples, and unsaturated diffusion tests on soil samples. The index tests revealed that the silty-sand sample contained 76 % sand and 24 % silt, and the clayey sample (silt and clay, trace sand) contained 6 % sand, 43 % silt and 41 % clay. The chloride diffusion coefficients of 1.6x10-9 m2/s and 1.3x10-9 m2/s were obtained for 1 Bar and 5Bar ceramic disks, respectively. The SWC tests on silty-sand and clayey samples showed that the samples drained minimal water up to 0.034 bar and 0.098 bar matric suction, respectively, after which the main water drainage started. The SWC curves obtained for silty-sand and clayey samples were in good agreement with the reported values for similar soils. Using the Tempe-Diffusion Apparatus, diffusion tests were performed for silty-sand and clayey samples. In silty-sand sample tests, chloride diffusion coefficients of 6.9x10-10m2/s, 5.6x10-10m2/s, and 3.5x10-10m2/s were obtained in 86.4%, 71.8 %, and 45.2 % degree of saturations, respectively. In clayey sample tests, chloride diffusion coefficients of 4.3x10-10m2/s, 3.4x10-10m2/s, and 2.0x10-10m2/s were obtained in 86.2 %, 68.5 %, and 38.2 % degree of saturations, respectively. These diffusion coefficients were obtained by fitting the theoretical data obtained by program POLLUTE into the observed data. These diffusion coefficients were in the range of the reported values for similar soils.
Year: 2009