Câmara, GustavoAzevedo, Nuno MonteiroMicaelo, Rui2025-10-062025-10-062025-082071-1050PURE: 130960407PURE UUID: 0339716f-60a3-4197-8b5d-32a70fd4397eScopus: 105014397981ORCID: /0000-0001-9910-1458/work/193625653http://hdl.handle.net/10362/189060Funding Information: This work is part of the research activity of the third author carried out at Civil Engineering Research and Innovation for Sustainability (CERIS) and has been funded by Funda\u00E7\u00E3o para a Ci\u00EAncia e a Tecnologia (FCT) in the framework of project UIDB/04625/2025. Publisher Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland.Capsule-based self-healing technologies offer a promising solution to extend pavement service life without requiring external activation. The effect of the capsule content on the mechanical behaviour of self-healing asphalt mixtures still needs to be understood. This study presents a numerical evaluation of the isolated effect of incorporating capsules containing encapsulated rejuvenators, at different volume contents, on the stiffness and strength of asphalt mixtures through a three-dimensional discrete-based programme (VirtualPM3DLab), which has been shown to predict well the experimental behaviour of asphalt mixtures. Uniaxial tension–compression cyclic and monotonic tensile tests on notched specimens are carried out for three capsule contents commonly adopted in experimental investigations (0.30, 0.75, and 1.25 wt.%). The results show that the effect on the stiffness modulus progressively increases as the capsule content grows in the asphalt mixture, with a reduction ranging from 4.3% to 12.3%. At the same time, the phase angle is marginally affected. The capsule continuum equivalent Young’s modulus has minimum influence on the overall rheological response, suggesting that the most critical parameter affecting asphalt mixture stiffness is the capsule content. Finally, while the peak tensile strength shows a maximum reduction of 12.4% at the highest capsule content, the stress–strain behaviour and damage evolution of the specimens remain largely unaffected. Most damaged contacts, which mainly include aggregate–mastic and mastic–mastic contacts, are highly localised around the notch tips. Contacts involving capsules remained intact during early and intermediate loading stages and only fractured during the final damage stage, suggesting a delayed activation consistent with the design of healing systems. The findings suggest that capsules within the studied contents may have a moderate impact on the mechanical properties of asphalt mixtures, especially for high-volume contents. For this reason, contents higher than 0.75 wt.% should be applied with caution.3062248engasphalt mixturescapsules contentdiscrete element methodmechanical assessmentsmart infrastructuressustainabilityComputer Science (miscellaneous)Geography, Planning and DevelopmentRenewable Energy, Sustainability and the EnvironmentEnvironmental Science (miscellaneous)Energy Engineering and Power TechnologyHardware and ArchitectureComputer Networks and CommunicationsManagement, Monitoring, Policy and LawSDG 7 - Affordable and Clean Energyjournal article10.3390/su17167502https://www.scopus.com/pages/publications/105014397981