Study on the control of the crosslinking bond breakage degree in crumb rubber desulphurisation and properties of the modified asphalt

Vulcanised rubber contains numerous cross-linking bonds. Desulphurisation breaks partial bonds of crumb rubber (CR), enhancing its use in asphalt. This study aimed to prepare modified asphalt with superior high/low-temperature performance and storage stability. Using engine oil (EO) and desulphuriser TESPT, degraded crumb rubber (DCR) was prepared via Harker mixer and twin-screw extruder. CR's fracture and desulphurisation degree were characterised via sol content, Horikxcurve, GPC, TG and FTIR. The physical and rheological properties of SBS/DCR composite modified asphalt (SDCRMA) were analysed by DSR, segregation tests and fluorescence microscopy. The results show that an appropriate desulphuriser facilitates the breakage of crosslinking bonds in CR, but excessive amounts will cause the breakage of the main chains. Moreover, adding SBS can enhance SDCRMA's high-temperature stiffness and low-temperature flexibility, boosting rutting resistance and promising for waste rubber utilisation and road construction.