Structure and performance evaluation on aged SBS modified bitumen with bi- or tri-epoxy reactive rejuvenating system

To cater for the concept of global green development, it is of importance, in the bituminous road domain, to achieve the objective of the high-quality rejuvenation of waste bitumen. This paper investigates physical properties, rheological properties, morphology and molecular structure of rejuvenated SBS modified bitumen (SMB) with 1, 4-butanediol diglycidyl ether (BUDGE) or trimethylolpropane triglycidyl ether (TMPGE). The results of physical properties indicate that BUDGE and TMPGE can both improve the low-temperature ductility and penetration of aged SMB, and by contrast, BUDGE can make the aged SMB more flexible at low temperature. From the rheological properties, BUDGE or TMPGE can help restore the crack resistance at low temperature and somewhat decrease the rutting resistance at high temperature, which relies on the reduction of fatigue factor and rutting factor of aged SMB. FTIR spectra and fluorescence images show that the original structure of SBS can be partly rebuilt through the chemical reaction between the terminal groups on BUDGE or TMPGE and the oxygen-containing reactive groups on degraded SBS.