Low-tech methods for the reuse of reinforced concrete structural elements

Abstract

Most of existing buildings are made of concrete, new buildings are being built with it and others are demolished when still in good structural condition. This drives increased demands for raw materials, greenhouse gas emissions, and an accumulation of demolition waste. When in-situ rehabilitation or transformation is deemed unfeasible, a promising circular economy strategy to reduce these impacts is to reuse reinforced concrete (RC) load-bearing elements from obsolete donor structures into new receiving structures. Consequently, there is a need to adapt methods and processes to the specificities of RC element reuse by integrating knowledge on existing structures, deconstruction and construction techniques and structural optimization. To facilitate the supply chain of reclaimed RC components, the planning and execution of the deconstruction of an obsolete donor structure must be linked to the planning and execution of the construction of a new receiving structure. Using three recent case studies in Switzerland, this paper highlights how low-tech methods and procedures can be used to plan RC element reuse. A complete set of tools is introduced to evaluate an existing donor structure, plan its optimal deconstruction, and design the new receiving building. They include a reusability assessment method, a reuse-driven design process, and a data validation procedure. The case studies confirm that, depending on transport distances, reusing RC elements in a new structure can save up to 75% of CO2-eq emissions compared to standard RC construction techniques.