Direct reuse of the end-of-use structural steel: Assessing the economic and carbon reduction effects

Due to increasing market demand and limited resources for utilization and allocation, the global economy faces mounting pressure. Construction and demolition waste (C&DW) is therefore considered a potentially significant source of secondary materials for the future. To prolong the service time of these end-of-use products within the construction sector, innovative business models for effectively utilizing these urban mines are emerging, with direct reuse strategies being one practical solution. Among various types of C&DW, the inherent properties of steel make it particularly favorable for direct reuse. This study develops a hybrid input–output analysis and environmental extended input–output analysis model to assess the economic and environmental impact of applying a direct reuse strategy in the construction sector, with a focus on end-of-use structural steel products from end-of-service buildings. Under the scenario that end-of-use structural steel is directly reused, the economy may experience slight output value losses owing to reduced demand for raw material and remanufacturing sectors. However, it can result in significant carbon reduction impacts on energy and raw material sectors. Moreover, the carbon reduction achieved through the direct reuse strategy is around 25% of that achieved by transitioning from blast furnace-basic oxygen furnace (BF-BOF) steelmaking process to direct reduced iron-electric arc furnace (DRI-EAF) steelmaking process. These findings indicate that the innovative direct reuse business strategy could effectively serve as a catalyst for reducing carbon emissions across the entire economy.