Desempenho hidráulico de solo enriquecido com bentonita para uso em liners de aterro sanitário

Abstract

This work aims to compare the hydraulic performance of compacted soil layers (CCL) improved with different sodium and calcium bentonite contents with the local soil from Crateús used for waterproofing landfills. To this end, physical and geotechnical characterization analyzes of the materials and their mixtures were carried out in order to evaluate the influence of bentonite on hydraulic conductivity. The laboratory tests included compaction, permeability and consistency limits tests, allowing the investigation of changes in soil properties with the addition of different percentages of bentonite. The results demonstrated that the increase in sodium and calcium bentonite significantly changed the hydraulic conductivity of the soil, highlighting the mixtures with sodium bentonite as the most efficient in reducing permeability. Mixtures with 10% sodium bentonite achieved hydraulic conductivity of less than 10−9 m/s, meeting USEPA requirements for waterproofing layers in landfills. It is concluded that sodium bentonite, compared to calcium bentonite, presents better results in relation to permeability for application in waterproofing layers of landfills, providing greater security against the infiltration of contaminants into the soil and groundwater.