Effect of Aging on Healing Capacity of Bituminous Composites Containing Polyphosphoric Acid

Abstract

This study examines how aging affects the healing capacity of bituminous composites containing polyphosphoric acid (PPA). PPA is a commonly used in bitumen to enhance its elasticity, however, its effectiveness highly depends on its environment, including internal and external factors. In terms of internal factors, the interplay between PPA and various bitumen modifiers have been extensively studied. Here, we studied how external factors such as exposure to ultraviolet radiation affect PPA’s efficacy, measured in terms of change in bitumen’s healing index. The study results showed that the introduction of PPA to bituminous composites significantly increases the bitumen healing index, however, the change in the healing index becomes less pronounced as aging progresses. The presence of other additive such as taconite were found to affect the efficacy of PPA with bitumen containing 30% taconite, which has the highest change in healing index in the presence of PPA. Overall, bitumen containing PPA had a higher healing index than those without PPA regardless of the extent of aging and dosage of modifiers. This, in turn, indicates that PPA is highly effective for enhancing bitumen healing. This can be attributed to the role of PPA in promoting intermolecular interactions within the bitumen matrix.