Engineering properties of used motor oil-contaminated soil treated by sawdust and fiber

One of the methods that is proved adequate and is still under study today is the treatment of hydrocarbon-contaminated materials by using bio-based agents such as sawdust. Despite the numerous studies on the remedial effect of sawdust on the soil, never have the engineering properties of sawdust-treated hydrocarbon-contaminated soils been investigated. Studying such properties is of great importance when it comes to construction over the treated grounds. In this study, the hydro-mechanical properties of a used motor oil (UMO)-contaminated soil treated by five different sawdust contents are evaluated through a complete set of experimental tests, namely standard compaction, direct shear, unconfined compressive strength (UCS), and falling-head conductivity tests. Since the results of the tests showed a degradation in UCS as a result of sawdust treatment, four different percentages of fibers were added to the treated soil and the same tests were conducted again. The results show a positive influence of sawdust on the shear strength, a negative influence on the UCS, and a major reduction in water conductivity. Fiber-reinforced sawdust-treated mixtures display a better shear response, a higher UCS, and an increased conductivity. Scanning electron microscopy (SEM) images also prove the efficacy of sawdust treatment in soil remediation and improvement.

Automated summary

This study investigates the hydro-mechanical properties of sawdust-treated hydrocarbon-contaminated soils. Experimental tests show that sawdust treatment has a positive influence on shear strength but a negative influence on unconfined compressive strength (UCS) and water conductivity. Fiber-reinforced mixtures of sawdust-treated soils display better shear response, higher UCS, and increased conductivity.