Interface Bonding Mechanism of Recycled Asphalt Mixture

With more and more asphalt pavement entering into maintenance period, a large number of aged and damaged asphalt pavements are excavated to reclaimed asphalt pavement. Recycling of old asphalt pavement into asphalt mixture is one of the important ways to solve this kind of waste material. However, the water stability of reclaimed asphalt mixture is difficult to meet the requirements of actual pavement performance, resulting in insufficient pavement durability. Water vapor weakens the bond between asphalt and aggregate and asphalt paste. In this paper, the failure mechanism of interfacial bond in asphalt mixture is summarized by using weak boundary layer, electrostatic force, chemical bond, mechanical bonding and surface free energy from the view of microstructure. Further more, the research direction of interfacial bonding mechanism of recycled asphalt mixture is put forward.