Concrete is the world’s second most-used material in construction, after water. It comprises three main ingredients: cement, water and aggregates. The latter constitute 60-70% of concrete’s total volume, representing a heavy environmental burden. Presently, the use of recycled aggregates (RA) in concrete production (reusing their embodied energy and decreasing waste dumping) is still marginal, even though its feasibility has been demonstrated at the research level. The overarching goal of the CIRCLE project is to form an international network of 11 organisations working to tackle the challenges in upscaling recycled aggregate concrete (RAC). The CIRCLE team includes interdisciplinary researchers renowned in this area, which will integrate their expertise towards the project’s overarching goal, following a carefully planned flowchart of activities: enhancing existing knowledge on bio-based self-healing and carbonation of RAC; fostering high-performance RAC; optimizing the quality of RA and RAC, and evaluating the potential of RAC through multi-criteria life cycle assessment; and assessing RAC in full-scale real applications. The intercontinental 342 PM planned in secondments within CIRCLE will be the vehicle for joint research, training and networking, which will benefit the institutions’ staff at all levels of seniority, as well as PhD students. CIRCLE spans European and Asian countries with a massive need for concrete infrastructure development. Given the overwhelming dominance of concrete worldwide as a structural material, the potential environmental, economic and social positive impacts of upscaling RAC are priceless. This has been perceived by authorities and stakeholders and there are ongoing initial efforts in some of the consortium countries to regulate this possibility, which makes CIRCLE very timely in terms of guidelines contribution. Promoting RAC through CIRCLE will foster sustainability and a circular economy, aligned with European and UN policies.