Enhancing construction material circularity: An integrated participatory systems model

The construction sector significantly contributes to resource depletion and waste generation due to its reliance on linear economic systems. While material circularity presents a solution by reintegrating materials into supply chains, existing research lacks a comprehensive analysis of the dynamic interdependencies among circularity practices, key drivers, enabling factors, and governance mechanisms. This study aims to develop a decision-support model that uncovers hidden systemic interactions among circularity variables. Employing an integrated participatory systems modelling approach, the research combines two analytical methods: cross-impact matrix multiplication applied to classification (MICMAC), which identifies key system variables and evaluates their driving and dependency relationships, and causal loop diagram (CLD), which visualises the feedback loops and interconnections among variables. Expert interviews were conducted during MICMAC analysis and CLD development to identify the relationships between variables and validate the proposed model. MICMAC analysis highlights end-of-life circularity solutions, circular material sourcing, and circular planning as the most dependent variables, while expert involvement, environmental regulations, and government funding emerge as the most influential variables. The CLD analysis reveals the feedback mechanisms and causal linkages, offering a comprehensive understanding of the dynamics that shape material circularity in the construction sector. Overall, the study advances both theoretical and practical understanding of material circularity in construction by offering a transferable decision-support model, actionable strategies across the building lifecycle, and policy recommendations, thereby laying a foundation for future research and system-based modelling in diverse socio-economic contexts.