Waste additives as biopolymers for the modification of bitumen: Mechanical performance and structural analysis characterization

This work deals with the use of cellulose and treated waste cellulose in order to improve the mechanical performance of bitumen. In particular, the cellulose deriving by waste of the agri-food industry was subject to preliminary acid treatment and bleaching step to remove completely lignin. The present research shows the effectiveness of this biopolymer as modifier for bitumen. Fundamental rheological tests, based on a state-of-the-art dynamic shear rheometer in the temperature range from 25 °C to 100 °C were performed to evaluate the viscoelastic properties of bitumen. The aggregates including cellulose were studied by using quantum mechanical calculations at DFT level of theory. DFT results suggest the spontaneous formation of complexes stabilised through weak interactions. In order to quantify all the established interactions responsible for the stabilization of the formed aggregates, Reduced Density Gradient analysis was performed.