Performance Evaluation of Extracted Asphalt Binders from Field Cores Containing Recycled Components: Load- and Non-Load-Associated Cracking Resistance

Modifying asphalt mixtures with recycled components is common practice due to their environmental and economic merits. However, due to the oxidized air-blown asphalt binders in recycled asphalt shingles (RAS) and aged binders in reclaimed asphalt pavement (RAP), adopting RAP and/or RAS as recycled components in asphalt mixtures influences the performance of the overall asphalt binder in these mixtures. The percentages of recycled components and performance grade (PG) of virgin asphalt binders (VABs) in the asphalt mixtures govern the performance of the overall asphalt binder. Therefore, the main idea of this study was to investigate the effect of the percentages of RAP/RAS and PGs of the VABs on the load- and non-load-associated cracking resistance of the extracted asphalt binders (EABs) from field cores. Rheological tests were performed on the EABs to assess the load-associated cracking (fatigue cracking) and non-load-associated cracking (low-temperature and block cracking) resistance. The VAB's PGs, mixtures' ages, and the percentages of RAP/RAS affected the EABs' cracking resistance. When compared to EABs from mixtures with lower amounts of RAP, employing RAS in the asphaltic mixtures improved EABs' resistance to fatigue and block cracking. However, using RAS deteriorated EABs' resistance to low-temperature cracking. Increasing the RAP's percentage in the asphaltic mixtures decreased the cracking resistance of the EABs. Strong relationships were established between EABs' load- and non-load-associated cracking resistance.