Stabilization/solidification (S/S) is a technique that has been widely used to treat contaminated soils using several types of stabilizers, such as ordinary Portland cement (OPC). In this research, marl soil that was collected from eastern Saudi Arabia was contaminated by either diesel or crude oil at different dosages (i.e., 2.5, 5, and 10% by the dry weight of the soil) and tested to assess its geotechnical and environmental properties. Thereafter, the contaminated soil was stabilized using OPC, limestone powder (LSP), and cement kiln dust (CKD) at different proportions. The contaminated-stabilized soils were evaluated by measuring the changes in their geotechnical properties, and both metal and hydrocarbon contents. Results of this investigation indicated that the S/S treatment of the contaminated soils enhanced the compaction characteristics with a significant improvement in the unconfined compressive strength (UCS) results, and all of S/S-treated mixtures were found to pass the strength criterion of the U.S. Environmental Protection Agency (USEPA) (i.e., 340 kPa after 28 days of curing). Moreover, The UCS results of the stabilized soils were compared to the minimum strength requirements for both paved and unpaved road materials (i.e., 1380 and 690 kPa, respectively). Finally, scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses were used to elucidate the changes in the microstructure of the stabilized soils.
Keywords: Contamination; Crude oil; Diesel; Marl; Microstructure; Stabilization/solidification.