Multicriteria analysis of the environmental and economic performance of circularity strategies for concrete waste recycling in Spain.

Construction and demolition waste (CDW) is identified by multiple circular economy (CE) policies as a key sector for implementing circularity strategies due to the high volume of waste produced and the large consumption of raw materials. However, CE is not widely applied in the sector because of the lack of solid estimations on its environmental and economic viability. The main aim of this study was to propose a set of methodological steps to identify the optimal circularity alternatives for CDW products based on a multicriteria analysis of their environmental and economic performance. This methodology is applied to evaluate concrete waste. In specific, high-grade applications of concrete waste were analyzed comprising the processing into recycled coarse aggregates (RCA) for their use in structural and non-structural concrete. Multiple scenarios with different RCA replacements (20%, 30% and 100%) and different types of sorting and recycling (on-site and off-site) were evaluated in accordance with the specific site conditions of the region of Catalonia, Spain. The Life Cycle Analysis methodology (LCA) was used to perform the environmental analysis, while a detailed cost analysis was conducted for the economic aspect. The multicriteria method VIKOR was used for the selection of alternatives considering three different criteria. The results of this study showed environmental and economic advantages of CE scenarios based on the use of RCA over conventional concrete, mainly due to the influence of landfilling and transport distances. RCA produced on-site showed a better performance than RCA from fixed plants.