Functional downcycling in reused structural steel: implications for life cycle and circularity assessment

Abstract

Structural steel reuse is increasingly promoted as a superior circular strategy, positioned above recycling within prevailing sustainability hierarchies. This ordering is typically justified because reuse avoids the energy and emissions associated with remelting, thereby preserving embodied carbon. However, such comparisons frequently rely on simplified carbon accounting assumptions and neglect system‐level effects in mature steel economies, where recycling rates are already high, and scrap availability is increasingly constrained.