Effect of hydrated lime and other mineral fillers on stiffening and oxidative ageing in bitumen mastic

•Investigating the effect of hydrated lime and other fillers on mastic stiffening and ageing.•Physical and chemical properties were evaluated to study the effect of hydrated lime.•The evaluation testing was aimed to understand the mechanisms of hydrated lime on ageing mitigation.•The results indicate that hydrated lime reduced the ageing indices more as compared to other fillers.•Hydrated lime mastics showed less carbonyl index and asphaltenes content than granite mastics. The bituminous binder's ageing process is the primary reason behind the decrement in the pavement's in-service life, which can lead to cracking as a result of extreme hardening of the binder. In order to mitigate this problem, several methods have been used, such as polymer modification, functional improvement and modification with nano-particles. Due to its exceptional performance in asphalt mixtures, hydrated lime has also been considered the potential antioxidant in recent studies. However, its impacts have not been well understood. Therefore, this study aims to investigate the effect of hydrated lime and other fillers on mastic stiffening and ageing. In this detailed study on mastics, the effect of hydrated lime on stiffening and ageing mitigation was evaluated by various means involving both physical and chemical properties. The evaluation testing was aimed at understanding the mechanisms of hydrated lime on ageing mitigation. Moreover, special attention was paid to the interactions between hydrated lime and bitumen, which affects bitumen mastics' ageing. The results indicate that hydrated lime reduced the ageing indices more as compared to other fillers. Further, increasing the concentration of hydrated lime resulted in more decrease of ageing indices just opposite to that of granite filler. Also, the bitumen recovered from the hydrated lime mastics showed less carbonyl index and asphaltenes content than granite mastics which prove the ability of hydrated lime to reduce the ageing products. Moreover, it is noticed that the mastics stiffness increased with an increase in the ageing time. The fillers can increase or decrease the ageing of the mastics as the time in the TFOT proceeds.