Laboratory performance and aging resistance evaluation of zinc oxide/expanded vermiculite composite modified asphalt binder and mixture

Abstract

It has been determined that the compositions of zinc oxide/expanded vermiculite (ZnO/EV) can exert synergetic effects on improving the aging resistance of asphalt, but road performance and aging resistance of the corresponding asphalt binder and mixture have been insufficiently researched, potentially limiting its future application. Thus, the physical properties (including the penetration, Ring-and-Ball softening point, ductility and rotational viscosity), continuous grading high and low temperature and aging resistance of asphalt containing ZnO/EV of various amounts were studied from the perspective of asphalt binder. From the perspective of asphalt mixture, the high- and low-temperature properties, moisture susceptibility, fatigue characteristics of the corresponding modified asphalt mixture before and after aging and its aging resistance were evaluated using various laboratory performance tests. Results show that adding ZnO/EV into asphalt could decrease the penetration and ductility of asphalt but enhance its softening point and viscosity characteristics, increasing the hardness and high-temperature stability of asphalt binder. The ZnO/EV with contents exceeding 3% can improve high- and low-temperature performances of asphalt binder, and its aging resistance can be improved by adding ZnO/EV and then decreasing the asphalt hardness enhancement and fluidity attenuation rate during aging. For that, the corresponding asphalt mixture possesses greater high- and low-temperature performances, lower moisture susceptibility and longer fatigue life than the unmodified asphalt mixture. Furthermore, the improved aging resistance by ZnO/EV can weaken the aging sensitivity of road performances for the corresponding mixture. Therefore, asphalt pavement will benefit from the application of the ZnO/EV modifier by reducing the occurrence risks of pavement distress and prolonging its service life.