Abstract

Encapsulated rejuvenators have become a promising way to crack-healing autonomously in bituminous materials. This work covers the synthesis of a biobased capsule as an additive to promote extrinsic self-healing in aged asphalt. With this objective, capsules with polynuclear microstructure were synthesised using alginate biopolymer as encapsulating material and sunflower oil as a rejuvenator. The thermal and mechanical stability of the capsules were evaluated by thermogravimetry and compressive tests. Four dense asphalt mixtures were manufactured to assess the capacity of the capsules. Capsules were added in 0.0%, 0.125%, 0.25%, and 0.5%wt content. The effect of the capsules in recovering the mechanical strength of cracked asphalt mixtures was evaluated based on a 3-step process, including mechanical cracking, capsule activation, and quantification of the healing level. The self-healing capacity of the non-encapsulated rejuvenator on aged bitumen was also assessed. The main results showed that the capsule design was thermally and mechanically stable to be incorporated in asphalt mixtures. Moreover, the sunflower oil effectively diffused into the cracked-aged bitumen with a softening effect that promoted its closure. Finally, the addition of capsules at 0.25% wt. Loading significantly improved the self-healing ability of the asphalt mixtures. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.