Characterization of thermal properties and combustion behaviour of asphalt mixtures in the cone calorimeter

• Asphalt mixtures with different thermo-physical properties were investigated.
• Open and dense graded mixtures showed different fire behaviours.
• Critical heat flux and ignition temperature were identified for dense graded mixtures.
• Performance-based criteria for asphalt with improved fire reaction were outlined.

In case of vehicle fires in highway tunnels, high temperatures, low visibility along with the emission of toxic and dangerous gases represent significant hazards for the safety of the vehicle passengers involved, as well as for the integrity of the tunnel structure. Thus, materials potentially exposed to fires must show adequate fire behaviour in order to guarantee the safety of passengers, rescue teams and structures. The present study addresses the characterization of thermal properties and combustion behaviour of different kinds of asphalt mixtures by means of cone calorimeter tests performed at different radiant heat fluxes. The results highlighted that coarse aggregates of different nature mainly affect the ignition properties of mixtures while the air voids content plays the leading role in governing the overall fire behaviour.