Assessment of induced-healing maintenance for cold-recycled asphalt concretes using microwave heating and re-compaction

Proving the healing capabilities of cold asphalt pavements has gained significant attention in recent years, particularly through innovative methods such as induction and microwave heating. While these techniques effectively promote asphalt healing, heating alone is often insufficient to fully restore the material’s initial strength. The integration of re-compaction energy has been proposed to improve the effectiveness of microwave-based treatments in asphalt mixtures. This study examines the induced self-healing potential of cold reclaimed asphalt mixtures incorporating recycled asphalt pavement materials with varying black steel mill slag contents (0%, 10%, and 20% w/w). Results showed that the high healing rate had been achieved, demonstrating complete recovery of the initial ITS and highlighting the effectiveness of microwave heating and re-compaction in restoring the mechanical integrity of the mixture. The chemical and mineralogical characterization of the black steel mill slag proved iron oxide phase with high dielectric properties, which significantly enhanced microwave absorption and heating efficiency. The asphalt concrete sample containing 20% slag reached temperatures notably higher than the reference mix. These findings highlight the potential of microwave-induced healing, combined with re-compaction, as a sustainable and cost-effective approach to prolong pavement lifespan, reduce maintenance costs, and promote environmentally friendly road rehabilitation.