Assessment of the compression characteristics and coefficient of lateral earth pressure of aggregate-expanded polystyrene beads composite fill-backfill using large oedometer experiments

We examined the compression behaviour of aggregate-expanded polystyrene (EPS) granular composites using large-size oedometer tests measuring directly the coefficient of lateral earth pressure at rest (K₀). The results showed that increasing the aggregate particles size led to a decrease of K₀ and the coefficient of volume compressibility, in pure aggregates and aggregate-EPS composites with rigid particles of d₅₀ < 2mm. Increased angularity and coefficient of uniformity were observed to display competitive mechanisms in controlling K₀. The increase of EPS content led to a transition from a behaviour dominated by aggregate contacts to aggregate-EPS and EPS-EPS major contributions in the load transfer mechanism.