Reintroducing the intrinsic self healing properties in reclaimed asphalt

In the Netherlands, 4 million tons of reclaimed asphalt (RA) were produced per year according to the European Asphalt Pavement Association (EAPA). Over 90% of the total reclaimed asphalt was reused into new asphalt constructions. However, for the most used new porous asphalt surface layer on the Dutch motorway system, the allowable RA percentage is only 25%. With the increasing needs of high percentage (up to 100%) and high performance (surface-to-surface) recycling due to both economic and environmental issues, it is of high importance to investigate the possibility to recycle the high quality surface layer (porous asphalt, stone mastic asphalt, etc.) RA back to the surface layers. The ultimate goal is to realize a 100% surface-to-surface asphalt recycling. In this research, a high performance material system (namely, rejuvenator) was developed to regenerate the flexibility and self-healing capability into the RA, which are the most important elements guaranteeing the long service life of asphalt mixtures. Based on the knowledge on the chemical/mechanical responses on the rejuvenated and re-aged bituminous materials, together with the in-situ diffusion analysis with Computer Tomography (CT) scan and Fourier Transform Infrared Spectroscopy (FTIR) measurements, a rejuvenator with excellent rejuvenating capability was developed. To evaluate the rejuvenating capability of the developed rejuvenator in a real application, a trial production was performed with a highly ecologic asphalt recycling (HERA) system by our project partners with high RA percentages, and a trial section was then constructed in 2014 with success. Experiments carried out on the cores drilled from the section indicated good performance. Now it is important to monitor the test section over time in order to gather more useful real service data. Based on the laboratory and field trial section results, it is expected that the developed rejuvenating product can guarantee a high performance surface-to-surface recycling.