Utilisation of construction and demolition waste in granular sub-base along with scrap tyre cellular reinforcement: a sustainable practice

This study explores the use of recycled materials such as recycled asphalt pavement (RAP) and recycled concrete aggregate (RCA) in the granular sub-base (GSB) layer, incorporating scrap tyres as cellular reinforcement. Laboratory repeated load tests are conducted on model pavement sections under both unreinforced and scrap tyre cell (STC) reinforced conditions. The results indicate that RAP sections experienced significant rutting within the initial 500 load cycles, suggesting a lower load-bearing capacity unsuitable for GSB application over the weak subgrade. Meanwhile, RCA demonstrated comparable performance to natural aggregates, making it a viable replacement. The integration of STC reinforcement proved effective in confining GSB materials, thereby enhancing pavement performance by reducing the plastic deformation and residual pressure at the subgrade level compared to the respective unreinforced section. Overall, the study recommends the use of scrap tyres and RCA in GSB providing cost-effective, sustainable, and environmental friendly pavement solutions.