Dual roles played by manganese dioxide filler in asphalt pavement material: Chemical modification and healing improvement.

• Manganese dioxide filler (MDF) changes the chemical composition of asphalt. • MDF improves rutting resistance of asphalt and strengthens the elastic feature. • MDF enhances the inherent and induction healing capacities of asphalt material. • The chemical modification of MDF is correlated with the performance change. The special physical and chemical features of manganese dioxide filler (MDF) provide feasibility for its application in asphalt pavement. At the physical level, MDF can absorb microwave energy and generate heat. The characteristic is expected to promote the induction healing capacity of asphalt concrete. At the chemical level, MDF is able to oxidize certain organic substances at high temperature. The property makes the utilization of MDF in asphalt modification possible. The research was induced to verify the application feasibility of MDF and clarify its action mechanism. Research efforts were paid on the effects of MDF on chemical composition, rheological properties and healing properties (inherent healing capacity and induction healing capacity) of asphalt materials. As results indicate, MDF changes the chemical composition of asphalt as predicted. As for rheological properties, MDF strengthens elastic characteristics and increases the high temperature stability of asphalt mastic. In contrast, MDF partially decreases the low temperature performance. Besides, MDF improves both inherent and induction healing capacities with different mechanisms. Statistical analysis implies MDF partly realizes above performance changes and healing promotion through changing chemical composition of asphalt. [ABSTRACT FROM AUTHOR]