The construction sector is one of the largest consumers of resources as well as a major source of CO₂ emissions and waste. Reinforced concrete, as a particularly energy-intensive building material, accounts for more than 40 percent of Germany’s building stock. While the reuse of non-load-bearing components is increasingly being implemented in practice, a transferable method for load-bearing concrete elements is still lacking. Technical, legal, and procedural barriers currently prevent this resource-intensive material group from being adequately maintained within the material cycle.

The project ZirKuS – Circular Construction and Structural Engineering aims to develop practical methods for reusing load-bearing reinforced concrete elements and to pave the way toward a circular construction practice. The focus lies on ecological effects such as reducing CO₂ emissions, waste volumes, and the demand for primary raw materials. By enabling direct reuse instead of energy-intensive recycling, the embodied grey energy within the concrete is preserved, significantly reducing environmental impact.

In the project, deconstructed reinforced concrete elements are analyzed using non-destructive testing methods, digitally recorded, and reinstalled in an experimental building. Newly developed reversible connection details enable resource-efficient, demountable assembly of the components. These connections are designed to be produced using standardized techniques accessible to small and medium-sized enterprises. The entire process – from digital recording to planning, preparation, and assembly – is carried out prototypically and assessed ecologically. Initial studies from preliminary work indicate CO₂e reductions and raw material savings of more than 60 percent compared to conventional new construction.

Furthermore, the project identifies regulatory and contractual barriers and develops proposals for adapted testing and approval procedures. The results flow into guidelines, educational formats, and digital tools to equip planning and construction practices for working with reused components.

ZirKuS combines ecological objectives with technical and procedural innovation. The project demonstrates how low-emission, resource-efficient construction can become a reality through practical component preparation and reuse at the element level, supported by digital methods and interdisciplinary collaboration.