Eco-friendly asphalt crack sealants for deicing salt-induced surface damage: material development and interfacial mechanism analysis

Asphalt pavements in cold regions are often exposed to deicing salts, which accelerate surface erosion, microcracking, and long-term durability loss. To solve this, a sustainable crack sealant was developed using microwave-pyrolyzed polypropylene (PP) and crumb rubber (CR). The PP serves as a reactive modifier, improving interfacial bonding and resistance to aging, while CR enhances elasticity and thermal stability. Laboratory tests were conducted to assess the viscoelastic properties, thermal stability, and bonding strength at varying PP and CR contents. The optimal formulation—comprising 5 wt.% pyrolyzed PP and 20 wt.% CR—demonstrated excellent deformation resistance at elevated temperatures and strong moisture resistance under winter conditions. Molecular dynamics simulations further highlighted the enhanced molecular interactions between the sealant and aged asphalt surfaces, facilitated by the pyrolyzed PP. These results underscore the potential of waste-derived materials in mitigating salt-induced pavement deterioration, providing an eco-friendly, cost-effective, and durable solution for road maintenance in cold climates.