Asphalt Pavement Resilience Under Wildfire: An Experimental Observation and Numerical Analysis

Abstract

Asphalt pavements are critical infrastructure components duringwildfires, ensuring evacuation, emergency response, and accessto essential services. Understanding asphalt deterioration underextreme heat is therefore vital. This study examines the thermal andmechanical responses of asphalt pavements subjected to wildfire-induced temperatures, focusing on structural and service perfor-mance. An integrated experimental/computational framework wasdeveloped to assess the wildfire resilience of three hot mix asphalt(HMA) types: conventional, boron-surrogated and wood sawdust-surrogated mixtures. Mechanical behaviour was evaluated throughMarshall stability and flow tests after controlled thermal exposure.Transient thermal conductivity measurements and finite elementsimulations were conducted to analyse heat transfer, while skid resis-tance and scanning electron microscopy tests assessed surface tex-ture, microstructure, and bitumen-aggregate interactions. Resultsindicate that wildfire exposure severely affects the upper 10 cmof pavement. Wood sawdust surrogated mixtures improved post-fire performance, highlighting the potential of sustainable, low-costmaterials for wildfire-resilient pavement design.