Effect of Encapsulation Combined with Microwave Heating on Self-Healing Performance of Asphalt Mixture

As an innovative maintenance technology of asphalt pavement, encapsulated rejuvenator used to improve its self-healing performance has been widely investigated by researchers in recent years. In this work, the self-healing properties of asphalt mixture with and without encapsulations were comparatively studied considering these parameters: Healing time, healing cycles and microwave heating. Three-point bending strength recovery test and fatigue loading cycles recovery test were conducted for two kinds of encapsulations containing the healing agents present inside the asphalt mixture, namely compartmented Ca-alginate/SiO2 fiber and compartmented Ca-alginate/graphene oxide fiber. The results showed that the optimum healing time was three days. After the 30 s of microwave heating, the recovery of fatigue loading cycles of asphalt mixture with compartmented Ca-alginate/ graphene oxide fiber was four times larger than that of control asphalt mixture. Compared with the single effect related to the encapsulated healing agent or temperature, the synergistic effect of temperature and encapsulation could further significantly improve the self-healing properties of asphalt mixture. The compartmented Ca-alginate/graphene oxide fiber not only could soften asphalt through the encapsulated healing agent to improve self-healing properties of asphalt, but also could repeatedly and quickly heal cracks thanks to microwave action. The synthesis of the fiber breaks the current boundary between the two technologies (capsules healing method and induction healing method) and opens up a new horizon for the asphalt self-healing technology.