Physical, rheological and chemical characterization of aging behaviors of thermochromic asphalt binder

- Thermochromic asphalt binders exhibit better aging resistance than blank sample.
- The recommended thermochromic powder content is 4%.
- CAI and VAI have tighter correlations with ΔCI compared to other aging indices.

As an innovative road material, thermochromic asphalt binder has great effect on keeping the surface temperature of pavement within relatively reasonable range. The objective of this paper was to investigate the anti-aging properties of asphalts containing 0, 2, 4, 6, 8% content of black thermochromic powders (named as blank sample, 2, 4, 6, 8% BTP binder for convenience). Three aging methods, including thin film oven test, pressure aging vessel test and ultraviolet radiation, were applied to simulate thermal and photo oxidation aging of asphalt, respectively. Physical and rheological properties of binders with and without thermochromic powders were measured before and after three aging methods. The results show that the introduction of black thermochromic powders could improve thermal stability and low-temperature cracking performance of asphalt binder. After three aging methods, all of thermochromic asphalt binders exhibit better aging resistance than blank sample by physical, rheological aging indices, and 4% is the optimal content in which thermochromic asphalt binder synthetically exhibits the best aging resistance. In addition, based on grey relational analysis (GRA), the aging indices of complex modulus aging index (CAI) and viscosity aging index (VAI) are more reliable in aging evaluation.

187