Assessment of smectite-rich claystones from Northpatagonia for their use as liner materials in landfills

Two types of Northpatagonic claystones (a commercially available sodium bentonite and selected smectite-rich claystones from the Upper Cretaceous Allen Formation) are considered as potential materials for landfill liners. To check the suitability of the claystones, physical (hydraulic conductivity, compaction, consolidation, and swelling), chemical (cation exchange capacity and bulk chemical analysis) and mineralogical analysis (X-ray diffraction and scanning electron microscope) were performed. Both claystone types showed very similar properties, which allow us to classify the smectite-rich claystones as bentonites. The high compressibility of the claystones makes them unsuitable to use them directly as liner materials. On the other hand, in combination with well graded sand, these materials satisfy the requirements stipulated by internationally accepted standards for compacted clay liners in municipal waste disposal repositories. In this way, a new applicability for clay materials of regional provenance was found.