Use of petroleum-contaminated drilling wastes as sub-base material for road construction

In this study, petroleum-contaminated drilling wastes were stabilized by mixing pozzolanic fly ash, lime and cement with them so they could be used as sub base materials for road construction. This stabilization produced physically, mechanically and chemically stabilized new mixtures. The laboratory study consisted of unconfined compressive strength, permeability, California bearing ratio, freeze/thaw (durability) and leachate on compacted stabilized samples, pH, electrical conductivity, cation exchange capacity and total metal contents on stabilized mixtures. Significant increases in the unconfined compressive strength, California bearing ratio, durability and pH were obtained by treating lime, fly ash and cement with petroleum drilling wastes. Significant decreases were obtained in electrical conductivity, cation exchange capacity, oil content and total metal concentrations both in mixtures and in leachate. The best result in all of the tests conducted was obtained with petroleum-contaminated soil stabilized with 20% lime, 10% fly ash and 5% cement. This mixture can be effectively and safely used as sub-base material.