Geosynthetic clay liners (GCL) have been increasingly used in barrier systems of waste disposal areas and in hydraulic works. However, sometimes they are discarded as possible barrier solutions in these works because of their greater costs in comparison with other solutions (geomembranes or compacted clay liners). This paper presents a laboratory study to investigate the technical feasibility of mixing alternative materials to bentonite for the production of alternative low cost GCLs. The alternative materials used were sand, clay and tire grains. Direct shear, consolidation, and expansibility tests were carried out on bentonite mixtures with varying percentages in mass of the alternative material. Ramp tests and expansibility tests were also performed on alternative GCLs manufactured with these types of mixtures. The results obtained showed that the presence of the alternative materials in the bentonite increased the shear strength and the permittivity of the mixture and reduced its expansibility. The tests on the bentonite-tire grains mixtures suggest that alternative GCLs manufactured with this type of mixture may be used in less critical barrier systems (particularly under high stress levels) and as bedding/protective layers underneath geomembranes, also providing a better use for wasted tires in environmental terms.

Keywords: GCL, alternative materials, laboratory tests, ramp tests,

Submitted on May 17, 2010.
Final Acceptance on November 03, 2010.
Discussion open until August 31, 2011.