Investigation of the optimal self-healing temperatures and healing time of asphalt binders

In this paper, the flow behaviors of asphalt binders were investigated through DSR viscosity-frequency sweep test to find out their potential optimal self-healing temperatures and the real self-healing ratios of the binders at different temperatures were measured through fatigue-healing-fatigue test to confirm the optimal self-healing temperatures. The healing time of asphalt binders needed for full healing was studied as well. It is found that both fresh and aged Pen bitumen binders show near-Newtonian fluid state at their softening point temperatures, at which asphalt binders showed optimal self-healing properties to heal fatigue damage. It is also found that ageing of the binder increases its optimal self-healing temperature. It means that the optimal temperatures of asphalt binders are associated to the bitumen type and ageing. Finally, the Wool and O's Connor model can be used to determine the healing time needed by asphalt binder to achieve full healing, where the accumulated dissipated energy recovery is recommend as a suitable healing index.