Effect of porosity on infrared healing of fatigue damage in asphalt

Nowadays most of our roads are made of asphalt mixes, a complex visco-elastoplastic material with self-healing properties. The present paper explores the effect of air voids content and their interconnectivity on the capacity of asphalt mixtures to heal fatigue cracks when a thermal infrared treatment is applied. Results showed that the percolation of air voids is required to optimise healing results. In samples with a lower content, the thermal expansion of bitumen and its flow through cracks can exceed the pore network's capacity. As a consequence, the internal pressure can increase enough to produce material damage instead of healing.