Evaluating circular economy strategies at the end-of-life stage of a mass timber building: pathways for sustainable construction

The construction sector is widely recognized as a significant contributor to environmental degradation, with its impacts intersecting with multiple sustainable development goals related to resource consumption, climate action, sustainable cities and communities, as well as industry and infrastructure. Integration of circular economy (CE) strategies at the end-of-life (EoL) of the constructions can reduce resource use, waste generation, therefore the impacts of this sector on the environment. The application of CE principles is considered a progressive act that requires the adaptation of infrastructures, and a sudden circular approach cannot be achieved. This study focuses on improving the circularity of EoL of the construction and demolition wastes (CDW). To this end, the environmental impacts of current EoL practices in Quebec, Canada, on a case study of mass timber building are evaluated. Then, by analyzing the sensitivity of the results to the application of several circular strategies, an optimized short-term circular pathway for Quebec’s construction sector is proposed. This short-term pathway includes a 20% increase in current CDW recycling and a 20% rise in wood and steel reuse, which serves as an initial step towards achieving a CE in the construction sector in Quebec. Mid-term and long-term pathways followed these results involve higher recycling and reusing of materials, along with integrating the reduction and refusal approaches as other CE strategies. The long-term pathway also encourages focusing on reducing the use of glue in mass timber products and considering more sustainable options like dowel laminated timber (DLT) in mass timber constructions. Application of circular economy (CE) strategies in construction sector is promotedSensitivity of life cycle assessment results to various CE strategies are calculatedShort-term circular pathway is a solution for an agile increase in material circularityLong-term circular pathways integrate reduce and refuse strategies of CEProposed circular pathways result in more sustainability in construction sector Application of circular economy (CE) strategies in construction sector is promoted Sensitivity of life cycle assessment results to various CE strategies are calculated Short-term circular pathway is a solution for an agile increase in material circularity Long-term circular pathways integrate reduce and refuse strategies of CE Proposed circular pathways result in more sustainability in construction sector