Assessing the environmental impacts of circular economy strategies on multi-residential buildings in Quebec, Canada: a case study approach

Research on sustainable construction has grown in response to the urgent need to address climate change. In Quebec, the construction sector is recognized both for its high environmental impacts and its strong potential for circularity. This comprehensive study goes beyond solely examining CO 2 emissions, covering a diverse spectrum of environmental indicators on construction and demolition wastes (CDW). It assesses and compares the ecological footprint of implementing circular economy strategies across four modeled multi-residential buildings in Montreal, Canada under various end-of-life (EoL) scenarios for CDWs. By evaluating divergences in EoL scenarios and exploring the potential benefits of cycling the materials, this study provides directions for improvements in Quebec. Conducted through an environmental life cycle assessment method, the findings underscore several critical points. Firstly, improving the EoL management of the building materials is crucial. Secondly, the results show lower environmental impacts for wooden buildings. Although the light wood frame building has the lowest environmental impacts, construction in mass timber shows greater potential for reducing environmental impacts when circular approaches are enhanced. Lastly, enhancing the recycling strategy will not necessarily result in lower environmental impacts, and the reuse strategy has to be prioritized. These insights reveal opportunities to better position mass timber in mid-rise construction and provide a starting point for Quebec to identify building types with higher circularity potential and to design strategies for increasing material circularity.