Buildings as Material Banks: Keeping Construction Materials in Circulation

The construction sector is one of the world’s largest consumers of raw materials and a major source of waste. Every year, vast quantities of concrete, brick, steel, and natural stone are removed from buildings and infrastructure. Much of this material is either discarded or used in low-value applications, despite still having significant potential as a resource. At the same time, the extraction of virgin materials continues to put increasing pressure on finite natural resources.

How can we meet future demand in the face of limited resources while strengthening the circular economy in the construction sector?

The answer lies in urban mining. This approach views existing buildings as material banks. Rather than simply demolishing buildings at the end of their service life, the materials they contain are identified, separated, processed, and reused wherever possible. The aim is to keep mineral construction materials such as concrete, masonry, and natural stone in circulation for as long as possible, reduce the consumption of virgin raw materials, and, through local reuse, avoid CO₂ emissions associated with long transport distances.

Digital building information models (BIM models / digital twins) can store information on the materials used within a building, ensuring that data on both the quality and quantity of these materials is available at the end of the building’s service life. The UniGR-CIRKLA project also investigates the material flows of mineral construction materials and steel within recycling processes. This enables a better understanding of material cycles across the entire building life cycle and supports more efficient planning of future demolition and recycling processes.

A particular focus is placed on the recovery of high-quality recycled aggregates from concrete and masonry demolition waste and their reuse in concrete production. The project therefore emphasizes not only recycling itself, but above all the quality and retention of value of materials, placing these aspects at the heart of a circular economy in the construction sector.