High-temperature, low-temperature and weathering aging performance of lignin modified asphalt binders

The objective of this work is to analyze the physical and chemical properties of lignin modified asphalt binders aiming to apply lignin obtained as a subproduct of the pulp and paper industry in asphaltic pavements. Lignin increased the Brookfield viscosity of binders mainly for 135 degrees C. Lignin modified asphalt binders registered a lower carbonyl index and thus a higher weathering aging resistance than the conventional binder, except for the binder with 4 wt.% of lignin after 200 h of weathering test. A content of 4 wt.% of lignin increased thermal stability of binder after the Rolling Thin Film Oven Test (RTFOT). Dynamic Shear Rheometer analysis showed that as the lignin content in binder increases, the stiffening increases as well and the corresponding high-temperature performance grade for unaged and RTFOT aged samples also improves. Lignin significantly improves the asphalt's resistance to thermal cracking at temperatures up to -12 degrees C.