Healing of bituminous mixtures incorporating bio-oil capsules and steel slag filler

Developing eco-friendly road pavement maintenance practices is essential to reduce environmental and economic impacts. In this context, bituminous mixtures with enhanced self-healing capacity, combined with healing-based maintenance techniques, can contribute to more sustainable pavements by extending service life and reducing associated costs. This study evaluates the healing performance of bituminous mixtures modified with encapsulated bio-oil and steel slag filler. Two healing procedures were applied: (1) a 6-h rest at 20 °C, and (2) post-damage compaction after heating at 50 °C. Healing performance was assessed using indexes based on dynamic modulus ( HIm ) and fatigue life ( HIc ). Procedure 2 enabled full stiffness recovery, with HIm reaching 100 %, and improved fatigue life by more than 50 % ( HIc ). In contrast, procedure 1 yielded lower recovery, with HIm limited to 50 % and HIc below 30 %. The incorporation of bio-oil capsules and steel slag filler did not significantly influence healing under the conditions tested. • Encapsulated bio-oil and steel slag filler did not affect stiffness properties. • Steel slag filler did not affect initial fatigue resistance. • 6-h resting period is suitable for promoting the healing of bituminous mixtures. • Greater recovery of fatigued beams is obtained with compaction. • Encapsulated bio-oil or steel slag filler did not contribute to recovery.