Influence of thermal history on the intermediate and low-temperature reversible aging properties of asphalt binders

This paper aims to investigate the influence of thermal history on the intermediate and low-temperature characterisation of asphalt binders. First, various asphalt binder intermediate and low-temperature characterisation methods and the significance of thermal history on asphalt characterisation were reviewed. Second, regular Superpave performance grading (PG) test, extended bending beam rheometer (Ex-BBR) test, double edge-notched tension (DENT) test and torsion bar low-temperature frequency sweep test were performed on selected asphalt samples with different treated thermal history. In addition, black space diagrams were also drawn to show the phase separation properties of varying asphalt binder formulations. The results showed that grade loss of wax-based warm mix asphalt almost kept constant when a small amount of microcrystalline wax (1% by mass of binder) was added. However, grade loss increased obviously with adding more microcrystalline wax (higher than 2%). Prolonged isothermal conditioning had a different degree of influence on the small-strain rheological and large-strain damage properties of asphalt binder. Applying slower loading frequency in dynamic shear rheometer (DSR) caused more obvious decrease in phase angle due to prolonged conditioning time.