Performance of wall mesh encased stone columns using recycled rubber concrete and asphalt aggregates for sustainable geotechnics

The growing volume of construction and demolition waste, together with discarded tires, highlights the urgent need for sustainable alternatives in soil improvement. Geosynthetic-encased stone columns (GESCs) are widely used to enhance bearing capacity and reduce settlement in soft soils, yet their reliance on natural aggregates contributes to resource depletion. To address this gap, this study evaluates the performance of GESCs constructed with recycled concrete aggregate (RCA), reclaimed asphalt pavement (RAP), and shredded waste rubber as partial replacements for natural gravel. A comprehensive experimental program consisting of 34 large-scale model tests was conducted with constant L/D ratio, two column diameters, and multiple material combinations. The findings show that several recycled mixtures, particularly those incorporating RCA and small rubber fractions, exhibited improved stiffness, enhanced stress–displacement response, and more controlled deformation compared with conventional gravel columns. Quantitatively, recycled-aggregate GESCs achieved up to 2% higher bearing capacity and Stress-to-Displacement Ratio of 12.6 compare to natural gravel columns, demonstrating their viability as an effective and environmentally sustainable ground-improvement solution.