Multi scale assessment of pavement deterioration and safety risk induced by post-accident hazardous spills

Road traffic safety remains a global priority, and pavement surface condition plays a critical role in ensuring adequate tyre–pavement interaction, vehicle controllability, and braking efficiency. While traditional deterioration mechanisms such as rutting, polishing, and ageing have been extensively studied, comparatively limited attention has been devoted to the effects of post-accident hazardous spills on pavement performance and safety. This doctoral research, developed within the framework of the PNRR-MOST Spoke 7 project on resilient networks and smart infrastructure, investigates the multi-scale mechanisms governing pavement deterioration and safety risk induced by post-accident hazardous spills. The study integrates laboratory experimentation, field validation, rapid surface characterisation, molecular-scale modelling, contaminant transport analysis, and traffic simulation to assess both urban and highway pavements. The results demonstrate that hazardous spills represent complex degradation triggers rather than temporary surface disturbances. On urban pavements, contaminant type was found to govern the predominant deterioration mechanism. Hydrocarbon fuels promoted binder softening and accelerated rutting, whereas viscous contaminants generated prolonged reductions in skid resistance. Although cleaning procedures mitigated the most immediate safety hazards, residual degradation effects persisted under subsequent traffic loading. A smartphone-based close-range photogrammetry methodology was successfully developed and validated for rapid texture assessment, providing a practical tool for post-incident pavement monitoring. Molecular dynamics simulations further clarified the physicochemical mechanisms underlying contaminant-specific deterioration behaviour.