Hydro-mechanical properties of unreinforced and fiber-reinforced used motor oil (UMO)-contaminated sand-bentonite mixtures

Abstract

Hydrocarbon contamination has been a challenging area of study in engineering geology (for example geotechnical, geo-environmental, and geological practices). Despite the relatively large number of investigations on the geotechnical and geological characteristics of hydrocarbon-contaminated soils, the improvement of these soils by fiber-reinforcement and interactions between contaminated soil and fibers have not been yet studied. In order to fill this scientific fact, standard compaction, direct shear, Unconfined Compressive Strength (UCS), and falling-head permeability tests were conducted on unreinforced and polypropylene (PP) fiber-reinforced Used Motor Oil (UMO)-contaminated sand bentonite mixtures. Accordingly, the shear strength is found to increase upon UMO contamination, while ductility is drastically decreased. UCS is impaired due to contamination and hydraulic conductivity is decreased. Results also reveal that despite the detrimental influence of UMO on the geotechnical properties of the soil, fiber reinforcement can contribute to direct shear, UCS, and ductility improvement. Hydraulic conductivity is found to slightly decrease initially and increase at high fiber contents.