Chloride effect diffusion coefficient of Bangkok clay

This research was aimed to determine chloride effective diffusion coefficient of soft Bangkok clay considering advection diffusion models. Laboratory column tests were conducted and a theoretical model was utilized to identify the relevant coefficient. Two different hydraulic gradients, 100 and 200, were maintained for the periods of 30-60 days for both constant and decreasing source concentration conditions. MnCI/sub 2/4H/sub 2/O was dissolved in de-ionized distilled water to produce the chloride solution of 0.004 molar. At the end of each test, the soil columns were horizontally sectioned to determine the amount of chloride with depth. For the extraction of chloride from soils de-ionized distilled water was used and the chemical analyses were performed with a spectrophotometer. The effective diffusion coefficients were determined by curve fitting using the computer code Pollute v 6. The values obtained from different testing conditions were consistent. However, these values showed some effects of source concentration conditions and negligible effects of hydraulic gradients on effective diffusion coefficient. (author)