Combustion kinetics of asphalt binder components and the release processes of gaseous products

To better understand thermal behaviors, combustion kinetic characteristics and dynamic releasing processes of gaseous products of four components separated from asphalt binder, thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) tests were conducted on each component at different heating rates, and both differential and integral methods were utilized to discuss their combustion kinetics characteristics, respectively. Results indicate that combustion processes of four components include the volatilization of light components in stage 1 and the combustion of charring layer in stage 2. Main mass losses of saturates and aromatics occur in stage 1, but the mass loss percentages of resins and asphaltenes in the two stages are almost equal. Thermal stability of four components is successively increased from saturates to aromatics, resins and asphaltenes. Also, there is a lag of combustion process due to more incomplete decomposition of each component at a higher heating rate. Temperature range of each combustion stage is widened as the heating rate is raised. Thermal decompositions of resins and asphaltenes are less affected by the heating rate than those of saturates and aromatics. Additionally, activation energy in each component combustion stage is calculated and collated by differential and integral methods, which are suitable to discuss combustion kinetics characteristics of four components and evaluate their thermal stability. Finally, the release rate and amount of gaseous products are increased at a higher heating rate. Combustion properties of asphalt materials are further understood at the component level. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.