Effects of loading rates on interfacial adhesion between aggregates and asphalt binders

Effects of loading rates on the adhesion between aggregate minerals and asphalt materials were elucidated through combined simulation and experimental studies. Silica, calcium carbonate and alumina represented the primary aggregate minerals, whereas saturate, asphaltene, resin, and aromatic represented the primary asphalt components. In the experiments and simulations, asphalt components and binders were pulled away from mineral interface at various loading rates. The relation between adhesion and loading rates was identified for the low-speed, transition and high-speed regions. Microstructural evolutions were characterized at different loading rates. Results showed that alumina generated higher adhesion to asphalt than silica and calcium carbonate, which agreed with prior experimental findings using particle probe scanning force microscopy. At low velocities, the gradual delamination of mineral-asphalt interfaces resulted in small adhesive forces. But at high velocities, the breakage of many bonds within a short period led to high adhesive forces. The study provided further understandings of the interfaces between aggregate and asphalt, which might promote the design and utilization of asphalt material.