Mechanical characterization of aggregates blended with scrap tyre for pavement construction: an experimental investigation addressing circular economy

In developing nations, material scarcity has impeded infrastructure development. Meanwhile, the generation of humongous amounts of non-biodegradable wastes has created health and environmental hazards. As a remedy to both issues, this study examines the feasibility of blending natural aggregates with shredded tyres for road construction. An experimental investigation was conducted on crushed rock/lateritic soil, partially (0–8%) substituted with shredded motorcycle tyres of two size ranges 0.6–6.3 mm and 6.3–12.5 mm. The test results revealed that the incorporation of shredded tyres reduces compacted density and California bearing ratio (CBR) but prosperously improves aggregate impact value (AIV), Los Angeles abrasion value (LAAV) and ten per cent fines value (TFV). As the shredded tyre size increases, compacted density, AIV, LAAV and TFV improve in CR-shredded tyre blends but decrease in LS mixes. The cost/density, cost/CBR and cost/TFV were comparatively lower for both aggregate types substituted with 2% shredded tyre. The lowest cost, AIV and LAAV were obtained for all mixes with 8% shredded tyre. In a nutshell, motorcycle shredded tyres of size ranges 0.6–6.3 mm and 6.3–12.5 mm can be incorporated in crushed rock up to 2% and 8% for the construction of a subbase and a granular capping layer of a flexible pavement, respectively.