Sustainable asphalt sealant with self-healing and salt-erosion resistance: laboratory design and molecular dynamics simulation based on interface performance

This study develops an eco-friendly asphalt sealant using recycled waste oil and nano-silica, with a focus on enhancing interface self-healing and salt-erosion resistance to promote sustainable pavement maintenance. The sealant incorporates 5 wt% nano-silica, which reduces chloride-ion diffusion by 48.6%. Additionally, 10 wt% recycled waste oil is introduced to enhance the self-healing properties at the interface, enabling crack recovery of over 74.6% at 60°C. Molecular dynamics simulations provide insights into the mechanisms at the interface, showing that long-chain hydrocarbons in waste oil reduce the energy barrier for crack closure, while nano-silica inhibits chloride ion adsorption at the interface, further improving the asphalt-aggregate bond. Laboratory tests confirm that the sealant improves interface adhesion strength, reduces stiffness, and enhances healing efficiency under salt exposure. This sustainable sealant not only offers a practical solution to replace traditional chemical additives but also promotes resource recycling, contributing to long-term durability and resilience of asphalt pavements through improved interfacial properties.