The effect of mineral additives and nanoparticle materials on the engineering behaviors of soils contaminated with waste engine oil

Due to the increasing population, redevelopment of polluted areas has become more popular during the urbanization process. Pollutions in these regions are mainly due to anthropic activities such as mining, metal industry and oil extraction, which not only degrade the environmental quality of the soils but also change the geotechnical properties of these soils. Therefore, in this study, it is aimed to investigate the changes in the engineering properties of waste motor oil and kaolin clay contaminated at different rates by using fly ash and nano-graphene materials. For this purpose, the physical and chemical properties of the materials were determined. Pure kaolin was contaminated with waste motor oil at different rates (3%, 5% and 9%) and on different days (1 and 7 days). Contaminated floors were treated with fly ash at various rates (10%, 25% and 45%) and nano-graphene (0.04%, 0.08% and 0.12%) for 1 and 7 days. After the physical properties of the samples were determined, uniaxial unconfined compressive strength (UCS) and consolidation tests were applied. Grey correlation analysis were made with the obtained data, and finally, the microstructural properties of the samples were examined with the ZEISS EVO MA10 scanning electron microscope. Experimental studies show that waste motor oil contamination causes serious changes in physical properties and decreases in UCS and consolidation parameters for pure kaolin. As a result of the improvements applied to the contaminated floors, a change has occurred in the physical properties again. An increase was observed in UCS and consolidation parameters. While the contribution of nano-graphene additive for the UCS experiment increased between 26.23% and 111.98% in addition to the fly ash additive, there was no such increase for the consolidation experiment. According to these results, it is recommended to use fly ash and nano-graphene together in terms of UCS, and only fly ash is recommended for consolidation properties when cost and labor are taken into account.