Compressibility of lateritic soil, bentonite and fibre mixtures for liners proposals

Abstract

Lateritic soils have potential applicability in geotechnical works because of its high mechanical strength when compacted, including flow barriers, such as liners in landfills, dam’s cut-off walls, and cut-off walls for containing contaminants. In this case, they are also required low hydraulic conductivity and compatibility with the surrounding fluid with the addition of bentonite the alternative usually employed to reduce the hydraulic conductivity and increased sorption capacity. On the order hand, the bentonite can increase the compressibility of the soil, deforming it and jeopardizing the integrity of the flow barrier. This paper presents the results of compressibility in mixtures of a lateritic soil, bentonite and fibers. Were tested lateritic soil and mixtures containing lateritic soil and 5% of bentonite besides mixture containing lateritic soil, 5% of bentonite and 1% of polypropylene fibers. The tests encompassed mineralogical characterization of lateritic soil and bentonite, evaluation of geotechnical properties and evaluation of compressibility in consolidation cell with 5 loading stages. Overall, results demonstrated increased of plasticity and compressibility in the laterite because of the addition of bentonite. On the order hand, the addition of polypropylene fibers in soil-bentonite mixture did not result in decreased of compressibility, demonstrating inefficient application of polypropylene fibers for use in liners.