Volume 35, N. 3, September-December 2012 | DOWNLOAD PDF(9 downloads)
Abstract
Compacted tropical soils have great potential to be used in barriers, once some technical issues are correctly addressed, including low hydraulic conductivity and compatibility to the disposed fluids. This paper involves a laboratorial study of the hydraulic conductivity of mixtures of a tropical soil sample and bentonite and also their compatibility to different chemical solutions. The experimental program consisted of (1) sample characterization, (2) hydraulic conductivity determination using a triaxial cell, and (3) compatibility assessment with different chemical solutions (HNO3, NaOH, NaCl, and ethanol) using the modified Atterberg Limits. The characterization results revealed important changes in the index properties of the tropical soil sample as the result of the bentonite addition, especially in the plasticity, cation exchange capacity and free swelling. The hydraulic conductivity, in turn, experimented significant decreasing as the proportions of bentonite and confining pressure increased. The compatibility results showed a significant reduction in the plasticity of the samples when subjected to the chemical solutions, especially for the salt solution. In general terms, the addition of bentonite reduced the compatibility of the samples.
