The reuse of building components is an extremely efficient way of reducing grey energy and greenhouse gas emissions in the construction of buildings. The research project "new circular processes for in-situ cast concrete structures" is a pioneering endeavour that is investigating the entire process from dismantling to the reuse of concrete structures. Detailed analyses, feasibility studies, life cycle assessments and cost calculations are being used to establish reuse on a larger scale. New technologies and processes for the sustainable decommissioning and reassembly of dismantled concrete elements are also being researched. The results of the project will be summarised in a series of guidelines and made available to the construction industry.