Diffusion and sorption-coupled transport of contaminated ground water in mineral sealing composite

摘要

A simple technique has been developed for measuring the ionic ingress into the surface layers of sealing composite specimens exposed to a salt solution, from which the apparent diffusivities for chloride, sul- phate, sodium, and potassium are derived. Results obtained have indicated that for a given composite, the depth of the ion diffusion is dependent upon the age of the specimens. If the sealing composite is older than about 2 years, i.e., the changes in its chemical compositions and microstructures are negligible com- pared to the rate of penetration of the ions, the apparent diffusivities determined from the diffusion equa- tion according to the second Fick's law can realistically characterise the diffusion and sorption-coupled transport of ions into the mineral sealing composite materials.