The Incorporation of Recycled Aggregate Concrete as a Strategy to Enhance the Circular Performance of Residential Building Structures in Spain

The construction industry increasingly relies on concrete to meet growing urban population demands. However, concrete has a high carbon footprint, which contradicts the Sustainable Development Goals and the Circular Economy policies promoted by the European Commission. The use of Recycled Aggregate Concrete (RAC) is a cost-effective circularity strategy to mitigate environmental impacts. Several countries have integrated RAC into their standards and have achieved promising circularity results. Spain is committed to enhancing resource productivity and using circular materials through practices established during the design phase. Although the residential sector plays a significant role within the construction industry, the potential for circularity of RAC in such residential building structures remains unexplored. The present study aims to fill this gap by assessing the circularity of four scenarios in a multi-family building using a circularity assessment method for residential building structures: the CARES Framework. The results reveal that RAC, following the Structural Code requirements, can enhance the circularity performance: at the material level by up to 42.82%; at the element level by 21.68%; and at the system level by 10.81%. These results demonstrate that circularity declines the higher the assessment levels is, which underscores the essential integration of circular materials with adaptability and disassembly criteria.