Mechanism and performance evaluation of secondary regeneration of asphalt

With the application of recycled asphalt pavements, many recycled roads will face secondary regeneration in the near future. The variation in properties of asphalt pavement after primary regeneration will directly affect the quality of secondary recycled asphalt pavement. To investigate the mechanisms and performance of secondary asphalt regeneration, this study conducted laboratory simulations to prepare primary aged asphalt and regenerated asphalt. Building upon the foundation of primary regenerated asphalt, secondary aged asphalt and regenerated asphalt were produced and subjected to testing. Subsequently, changes in the chemical composition, functional group contents, and rheological properties of asphalt, before and after two rounds of regeneration, were analyzed through Thin-Layer Chromatography with Flame Ionization Detection (TLC-FID), Fourier Transform Infrared (FTIR) spectroscopy, and Dynamic Shear Rheometer (DSR) testing. The results indicate that generic fractions can largely be restored to primary regeneration levels during secondary asphalt regeneration by incorporating regenerant and new asphalt. However, the carbonyl and sulfoxide indices are not effectively recovered in the secondary regeneration process, resulting in viscoelastic properties that do not match those of primary asphalt regeneration.