Mechanical, environmental and economic analysis of rejuvenated recycled asphalt mixes for surface course applications

Objectives The increasing use of reclaimed asphalt pavement (RAP) in surface courses presents challenges related to mechanical performance, environmental sustainability, and economic feasibility, particularly under Indian conditions. This study evaluated the feasibility of incorporating up to 40% RAP into bituminous concrete Grade-II (BC-II) mixtures using a bio-oil-based rejuvenator, considering mechanical, environmental, and economic performance.Methods BC-II mixtures containing 0%, 20%, 30%, and 40% RAP were prepared and evaluated. The required rejuvenator dosage was determined using a dynamic shear rheometer (DSR)-based blending chart approach. Mechanical performance was assessed through indirect tensile strength (ITS), tensile strength ratio (TSR), resilient modulus (MR), and indirect tensile fatigue tests (ITFT). Cradle-to-gate life cycle assessment (LCA), economic analysis, and transportation sensitivity analyses were conducted to quantify environmental impacts, production costs, and transportation-related constraints.Findings Mixtures containing up to 30% RAP required no rejuvenator, whereas the 40% RAP mixture required 0.5% rejuvenator by weight of RAP binder. RAP incorporation enhanced mixture stiffness, moisture resistance, and fatigue life, with the rejuvenated 40% RAP mixture demonstrating superior performance. The 40% RAP mixture reduced global warming potential by 26.5% compared with the control mixture, while production cost savings reached 28%. Sensitivity analyses identified RAP transportation distances within which environmental and economic benefits were maintained.Novelty This study provides an integrated mechanical, environmental, and economic evaluation of RAP-modified BC-II surface mixtures under Indian conditions, demonstrating the feasibility of 40% RAP incorporation and offering evidence to support revisions to existing RAP utilisation limits in pavement specifications.