Effect and Mechanism of Rejuvenation of Field-Aged Bitumen Extracted from Reclaimed Asphalt Pavement

Due to wear and exposure to atmospheric agents, road pavements are subject to an inevitable aging process. Asphalt rejuvenating agents implement the reorganization of the colloidal structure of aged bitumen as well as the restoration of the correct asphaltene/maltene ratio. In recent years, several incentives have been put in place regarding conservation of resources and safeguarding the environment by avoiding waste and promoting a circular economy. Reclaimed Asphalt Pavement (RAP) is one of the ways to promote and implement circular economy practices. Recovery of bitumen from RAP conglomerate is a viable way of recycling aged bitumen for use in new pavements. Aged bitumen binder from RAP however needs to be rejuvenated in order to restore its virgin properties for it to be suitable for new paving operations. This paper evaluates the effectiveness of a rejuvenating agent on reclaimed asphalt pavement through both the analysis of the mechanical modulus and the inner microstructural of the samples. These were conducted through Dynamic Shear Rheology (DSR), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC) and light microscopy.