Performance Evaluation of Anti-Ultraviolet Ageing Bitumen with Combined Modification Based on Dynamic Rheological Test

Based on the rheological property master curve, a new definition of ageing index was proposed for styrene-butadiene-styrene block copolymer (SBS) modified bitumen. The UV ageing resistance of the combined-modifier modified SBS bitumen was evaluated. Twelve different methods of combined modification were designed with three kinds of modifiers: ultraviolet absorber (Tinuvin 770), organic montmorillonite (OMMT) and layered double hydroxide (LDHs). With modified SBS bitumen, short-term ageing (TFOT) and laboratory ultraviolet ageing (UV) were performed. The dynamic shear rheometer (DSR) was used to perform frequency sweep test on the samples before and after ageing. The rheological property master curve was obtained by fitting the constitutive model equation. Based on the rheological property master curve, a new definition ageing index was proposed for SBS bitumen to evaluate the modified bitumen with different combined-modifier. The results show that the ageing index could effectively evaluate the UV ageing resistance of SBS bitumen. The evaluation results show that the combined-modifier bitumen exhibits better anti-ultraviolet ageing effects than a single modifier. Among them, the combined-modifier modes of 0.3%Tinuvin770+5%OMMT and 0.6%Tinuvin770+2.5%LDHs performed.