Towards post-fossil fuel road engineering : investigating the ageing behaviour of bio-rejuvenated binders for asphalt pavements

In an attempt to reduce waste disposals and to enhance environmental sustainability, several efforts are being made in research to promote the use of sustainable alternatives to conventional asphalt pavements. Currently, one of the main goals is to reduce the amount of virgin materials for new mixtures through the use of high Reclaimed Asphalt (RA) content including rejuvenators. It has been already proven that rejuvenators are able to restore some of the properties of the aged binder present in RA, but nowadays their effects on the ageing of new mixtures are not well-known. In this regard, in order to go a step further on the knowledge about these materials, this investigation aims at showing the rejuvenated binders properties and how these binders age. For this purpose, two RA binders from different RA sources and therefore different initial state were rejuvenated with a non-petroleum additive. The rejuvenator dosage selection and the ageing study were carried out conducting fundamental, chemical, rheological and performance related tests on the binders considering three ageing steps. The fundamental and rheological properties were further investigated in order to carry out a blending binder design, a methodology used when high RA content mixture are taken into account. Ageing Indexes (AIs) were obtained for all the properties and materials studied. Results showed that the additive could effectively restore the properties of the aged binder up to a target, allowing the use of high RA percentages in new mixtures. AIs revealed that the ageing of virgin bitumen is slightly higher than that of the rejuvenated one for some properties and slightly lower for others. However, this difference does not adversely affect the performance of the rejuvenated binder which showed comparable or better performance than the virgin one.