Effect of chloride salt erosion on interfacial adhesion characteristics of SBS/CR composite modified asphalt

This study aims to investigate the interfacial damage characteristics of SBS/CR composite modified asphalt (SBS/CRCMA) and aggregate in a salt-rich environment. The mechanism of chloride salt erosion on the SBS/CRCMA-aggregate interfacial system was systematically analysed by pull-off tests and molecular dynamics simulation methods. The results showed that the strength of the asphalt-aggregate interface decreased with the increase in solution soaking time and temperature. During the immersion process, the solution undergoes a migration phenomenon at the asphalt-aggregate interface region, leading to an increase in the asphalt spalling rate. The introduction of salt ions leads to tighter intermolecular bonding, resulting in lower solution migration height and slower migration rate. With the increase in NaCl solution concentration, the migration rate of the solution gradually decreases. In contrast, an increase in temperature enhances the migration rate of the solution. In addition, increases in temperature and NaCl concentration cause ion trajectories to become more complex and divergent, thereby increasing the risk of asphalt corrosion damage. During the migration process of the NaCl solution, the redistribution phenomenon of SBS/CRCMA components occurred at the interface. With the increase in temperature and NaCl concentration, the distribution of the components tends to homogenise.