Evaluation of carbon and economic benefits of producing recycled aggregates from construction and demolition waste

Abstract

Using construction and demolition waste (CDW) to produce recycled aggregate (RA) can limit the need for CDW landfills and reduce natural aggregate (NA) consumption; however, the RA production process generates carbon emissions and incurs economic costs. Therefore, it is necessary to study the environmental and economic feasibility of using CDW to produce RA. In this study, the environmental and economic benefits of RA production from CDW were evaluated based on life cycle assessment (LCA) and life cycle cost (LCC). To conduct a thorough evaluation, sensitivity and scenario analyses were conducted on the key parameters affecting carbon and economic benefits. Accordingly, potential improvements in the current system were analyzed to optimize the RA production process. The results indicated that using CDW to produce RA was environmentally and economically feasible. Sensitivity and scenario analyses indicated that using selective demolition and mobile production mode, pre-screening of CDW, opting for electric transportation vehicles, and increasing the CDW landfill disposal fee could effectively increase the carbon and economic benefits of RA production from CDW. Moreover, the CDW transportation distance had a significant impact on these benefits; thus, appropriately planning the transportation route was crucial. The results of this study provide a theoretical basis for assessing the feasibility of recycling CDW to produce RA and can also guide the optimization and improvement of the RA production process.