Thermal oxidative aging mechanism of lignin modified bitumen

Lignin is the most abundant renewable resource in nature, which can be applied to not only improve resource utilization but also improve bitumen road performance. In this study, the evolution of lignin during thermal -oxidative aging of bitumen was investigated by dynamic shear rheology test (DSR), thermogravimetric test (TG) and Fourier transform infrared spectroscopy (FTIR). The thermo-oxidative aging mechanism of lignin modified bitumen was analyzed. The results show that lignin-modified bitumen had better aging resistance than the virgin bitumen. Meanwhile, the changes of functional group indices at 1460 cm-1, 1512 cm-1, and 1600 cm-1 in the infrared spectra proved that the thermal-oxidative aging mechanism was the decomposition of lignin itself under the action of thermal oxygen, which inhibited the aging process of bitumen.