Cracking performance characterisation of asphalt mixtures containing reclaimed asphalt pavement with hybrid binder

摘要

This study investigated the effect of reclaimed asphalt pavement (RAP) on the rheological properties of a hybrid binder and the fracture properties and cracking performance of resultant mixtures. Fracture properties of the same mixtures containing up to 40% RAP with a standard polymer-modified asphalt (PMA) binder were used as benchmarks. RAP mixtures with hybrid binder exhibited lower resilient modulus, higher failure strain and higher fracture energy density than PMA RAP mixtures. Results indicated that rubber particles might not dissolve in the base binder; therefore, hybrid binder had more "free" soft binder to blend with the RAP whereas the more integrated polymer network present in PMA binder resulted in stiffer mixtures. Furthermore, PMA RAP mixtures exhibited lower damage accumulation rate than hybrid RAP mixtures. Eventually, hybrid and PMA RAP mixtures yielded comparable energy ratio values, which indicate both binder types can be interchangeably used in mixtures with up to 40% RAP for satisfactory cracking performance.