Salt Diffusion in Compacted Plastic Clay: Experimental and Theoretical Evaluation

Abstract: In this paper, experimental results of diffusion transport of salt through compacted, saturated bentonite clay was presented. Two different diffusion techniques namely, through-diffusion and half-cell method were used to obtain diffusion and retention characteristics of the bentonite specimen which has a potential application as a liner material in engineered landfills and backfill material in high-level nuclear waste repository. The experiments were carried out on duplicate specimens subjected to the same initial compacted density and concentration gradient to understand the underlying mechanism of both the experimental techniques. A graphical user interface (GUI) based on Dot-Net application, CONTRADIS, was utilized to estimate the model parameters by inverse analysis on the experimental data. The GUI utilizes the analytical solutions for analyzing the data obtained from through-diffusion and half-cell technique. The design model parameters obtained from the two techniques were analyzed and compared with the batch sorption experiments.