MECHANICAL BEHAVIOUR AND COMPACTION CHARACTERISTICS OF SHREDDED EXPANDED POLYSTYRENE MIXED CLAYEY SOILS

Abstract

One of the emerging problems of the modern day is the safe disposal of expanded polystyrene (EPS) waste and the successful recycling of it. The engineering properties of mixing coarsegrained non-plastic soils with various EPS waste types to create lightweight fill materials have been the focus of various studies in the latest decades. However, limited research work has been done on the deformation and strength response of fine-grained clayey soils combined with EPS waste, and it is still unknown how soil plasticity affects this reaction. In this work, the experimental analysis of three different kinds of fine-grained soils mixed with shredded EPS waste, ranging from 0.5% to 3.0% shredded EPS content, was done to determine the compaction properties, strength, and consistency limits. As a result of the incorporation of shredded EPS, the maximum unit weight of all three types of clayey soils was significantly reduced, resulting in the development of lightweight fills. The findings of direct shear testing showed that as the percentage of shredded EPS increased, there was an improvement in the frictional strength and a drop in cohesiveness. Unconfined compressive strength (UCS) seemed to enhance initially as shredded EPS content increased and to decrease subsequently when shredded EPS proportion increased further. The plasticity indices of the shredded-EPS mixtures were observed to be much lower than those of the untreated clays, and the workability of the shredded-EPS mixed clayey soils also improved. Finally, a framework based on the ideal shredded EPS content is suggested, which offers optimized strength at the lowest unit weight for the three different clayey soils.