Michela Alfe ¹ valentina Gargiulo ¹ Giovanna Ruoppolo ¹ Francesco Cammarota ² Pietro Calandra ^1* Cesare Oliviero Rossi ² Valeria Loise ² Michele Porto ² Paolino Caputo ²

• ¹ National Research Council (CNR), Roma, Italy
• ² University of Calabria, Cosenza, Calabria, Italy

Bitumen is the viscoelastic fluid binding the crushed stones and the mineral aggregates making the asphalt material in road pavements throughout the world. Since paving procedure, loss of more volatile compounds and oxidization processes take place with variation of the mechanical characteristics (aging): the material becomes rigid, stiff and brittle so it needs to be replaced with new one. The aged asphalts, instead of being landfilled, could be re-used for new pavements if a pretreatment with specific additives to restore its original properties is made. Paying attention towards conscious use of natural resources, we propose to use the condensable fraction (oil) obtained from the pyrolysis of waste tires (WT) as an agent to rejuvenate an aged bitumen. The WT pyrolysis oil has been produced and characterized by elemental analysis, gas chromatography coupled with mass spectrometry (GC-MS) and thermogravimetry. Bitumen was aged by RTFOT procedure and blended with WT pyrolysis oil at three different oil contents (1, 3, 6 % wt/wt) and the rheological behavior evaluated. The blends have been also investigated by atomic force microscopy and the asphaltenic fraction by optical microscopy. All the data consistently indicate that the oil addition not only can reduce the bitumen viscosity, restoring it to values close to the original, unaged, bitumen, but also can change the intermolecular structure to recover the self-assembly pattern typical of the unaged samples. The physicochemical mechanism of this phenomenon has been proposed in the light of the oil characteristics. For these reasons it can be concluded that the oil coming from the waste tires pyrolysis can be used to rejuvenate asphalts. This finding can be used in Reclaimed Asphalt Pavement (RAP) technology. The impact of this result is expected to be high because bitumens are used for road pavement throughout the world. In addition, since the urban waste treatment and asphalt maintenance processes are coupled/fused, two wastes (oil from waste pyrolysis on a side and aged bitumens on the other side) are simultaneously recovered/reused to produce new and performing asphalts.