Abstract

This study analyses the diffusion transport of sunflower oil as a rejuvenator through biopolymeric microcapsules for asphalt self-healing. The capsules were synthesised via emulsification and ionic gelation using sodium alginate, resulting in spherical capsules with an average diameter of 1.17 mm. Multiscale analysis incorporating morphological, mechanical, chemical, and transport characterisations provided insights into capsule stability, composition, and controlled release properties. Scanning Electron Microscopy confirmed the formation of polynuclear capsules without damage and with a polymeric appearance. Fourier-Transform Infrared Spectroscopy verified the preservation of the key functional groups during the encapsulation process. The compression test showed appropriate stability, with yield forces of 6.143 N. Controlled capsule fracture-release enabled diffusion transport modelling, revealing zero-order release kinetics of sunflower oil through the capsule matrix with a diffusion coefficient of 4.80 × 10–6m2/s. This study, including novel measurements of oil released from ruptured capsules, contributes to an understanding of the activation and release phenomena of encapsulated rejuvenators for asphalt self-healing. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.