The compressive strength of cement stabilized backfill: Polystyrene beads composites

The aim of this research was to evaluate the compressive strength (UCS) of lightly cemented geocomposites, developed from the blending of recycled waste plastic, Expanded Polystyrene beads (EPS) and granular backfill soil materials. The major emphasis is on the relationship between textural properties of two backfill materials (residual gravel backfill RGB, and residual fine sand RFS) and the strength properties of the geocomposites. Series of compression test were performed on the cement stabilized residual backfill soils containing different amount of polystyrene beads. Mixed variations of 4%, 8% and 12% of cement and 0.1, 0.2, 0.3, 0.4 and 0.5% of polystyrene by weight of sand of backfill were investigated. The change in the dry and soaked strength of the RGF—geocomposite with polystyrene additions was strongly bilinear, and stiff for polystyrene content less than 0.2%. However beyond 0.2%, the change in UCS with polymer increased sharply and post curing cracks were visible. An opposite trend was exhibited by the RFS—geocomposite. The two phase behavior is essentially dependent on the interlocking properties of the matrix. The amount of EPS waste used in low cost masonry is mainly dependent on the fines content.