Evaluation of expanded polystyrene as a lightweight material in road construction under cyclic loading

The construction industry is increasingly seeking sustainable materials to address the limitations of conventional subgrade materials in road construction. This research investigates the application of expanded polystyrene (EPS) as a subgrade material to improve the performance of road pavements subjected to cyclic loading. It explores EPS’s potential as an effective and sustainable alternative for subgrade materials in road construction. The findings may suggest that utilizing EPS can extend pavement lifespan and lower maintenance costs under certain conditions. The study involved experimental tests using Expanded Polystyrene (EPS) blocks with varying densities and thicknesses, positioned beneath sand subgrade layers to simulate road traffic conditions and evaluate their effect on roadway performance. The findings indicate that EPS considerably reduces both total and permanent settlement in road pavements. Specifically, higher-density EPS blocks exhibit improved load-bearing capacity and enhanced resistance to deformation. Furthermore, increasing the density of EPS boosts its performance under cyclic loading. Employing thicker reinforcement layers leads to even more significant reductions in settlement. Key outcomes include a 20–35% reduction in soil settlement when using EPS, as well as significant improvements in load distribution and resilience under cyclic loading, particularly in configurations utilizing high-density EPS combined with geosynthetic reinforcements.