Evaluating the long-term cracking resistance of asphalt binder modified with bio-based softeners using poker-chip test

Abstract

Bio-based softeners, or bio-additives, are increasingly utilized as sustainable solutions for adjusting asphalt performance grading or rejuvenating aged binders in reclaimed asphalt pavements. However, comprehensive studies on the bio-based softener family remain limited, and their long-term effects on asphalt binder cracking performance are not well understood. This study evaluates four softeners with varying origins to examine their type- and dosage-dependent impacts on asphalt binder. Aging conditions, including RTFO, PAV20, PAV40, and PAV60, were employed to simulate long-term oxidative aging, while the poker-chip test was used to assess binder cracking performance. Results demonstrate the long-term effectiveness of bio-based softeners in enhancing cracking resistance, with significant improvements in poker-chip ductility under extended aging conditions. Additionally, the performance of bio-based softeners was found to be dosage-sensitive, with even a 1% dosage significantly improving cracking resistance, while higher dosages yielded further enhancements. This study highlights the potential of bio-based softeners as sustainable materials for significantly improving the long-term cracking performance of asphalt binders.