Asphalt pavement resilience under wildfire: an experimental observation and numerical analysis

Asphalt pavements are critical infrastructure components during wildfires, ensuring evacuation, emergency response, and access to essential services. Understanding asphalt deterioration under extreme heat is therefore vital. This study examines the thermal and mechanical responses of asphalt pavements subjected to wildfire-induced temperatures, focusing on structural and service performance. An integrated experimental/computational framework was developed to assess the wildfire resilience of three hot mix asphalt (HMA) types: conventional, boron-surrogated and wood sawdust-surrogated mixtures. Mechanical behaviour was evaluated through Marshall stability and flow tests after controlled thermal exposure. Transient thermal conductivity measurements and finite element simulations were conducted to analyse heat transfer, while skid resistance and scanning electron microscopy tests assessed surface texture, microstructure, and bitumen-aggregate interactions. Results indicate that wildfire exposure severely affects the upper 10 cm of pavement. Wood sawdust surrogated mixtures improved post-fire performance, highlighting the potential of sustainable, low-cost materials for wildfire-resilient pavement design.