Using rheology to study environmental coupling effects and aging behaviors of bitumen under multi-environment coupling aging

Bituminous pavement is easily deteriorated by environmental factors during service, which negatively impacts its performance and service life. Effects of environmental factors on rheological performance of bitumen were investigated by heat, oxygen and ultraviolet coupling aging. Coupling effects and bitumen aging behaviors in different environments were analyzed. The results showed that modifier enhanced aging resistance of SBS modified bitumen compared to virgin bitumen. Heat-oxygen aging could affect bitumen more than heat-ultraviolet aging when aging time reached 234 h or 390 h. G-R parameter values under single aging factors did not exceed 20 times the values before aging. Single aging factors had low impact on fatigue resistance of bitumen. Only the heat-oxygen-ultraviolet coupling aging condition showed a large increase. Modified bitumen had better low-temperature cracking resistance. G-R parameters were sensitive to the coupling effect between different environments of bitumen. The more complex the coupling environments, the more severe the aging of bitumen. Aging performance under single aging conditions would reach the slow growth stage more quickly than under coupling aging conditions.