Decarbonizing the Construction Industry: A Critical Review of Sustainable Materials and Circular Economy Approaches

The decarbonization of the construction sector requires accounting for emissions throughout the entire life cycle of a building's materials, including extraction, manufacturing, construction, maintenance, replacement, and end-of-life, rather than operational energy alone. This paper offers a critical, rather than descriptive, narrative review of the evidence for sustainable construction materials and circular economy strategies as levers for whole-life carbon reduction. Rather than treating reported decarbonization potentials as settled findings, the review interrogates the assumptions, system boundaries, and evidentiary basis underlying claims made for low-clinker cement, alternative binders, recycled and low-carbon steel, bio-based materials, and secondary resources. A recurring pattern emerges: reported benefits are frequently derived from laboratory-scale, pilot, or early-commercial data, extrapolated using inconsistent life-cycle assessment (LCA) boundaries, and rarely validated against long-term, in-service performance. Circular strategies, including material demand reduction, adaptive reuse, component reuse, high-value recycling, design for adaptability and disassembly, urban mining, and digital traceability, exhibit a similar pattern: plausible mechanisms supported by a thin, methodologically heterogeneous, and geographically skewed empirical base. Wood products warrant particular consideration because sustainably sourced wood can store carbon and may reduce fossil-intensive material demand through substitution, although the magnitude and durability of these benefits depend strongly on accounting assumptions not yet harmonized across the field. The review argues that the field's persistent framing of sustainable materials and circularity as self-evidently complementary and beneficial obscures unresolved trade-offs, weak causal evidence for claimed emissions reductions, inconsistent counterfactual assumptions, and a systematic evidence gap outside high-income economies. It concludes that progress is currently constrained less by a shortage of candidate technologies than by the absence of harmonized carbon accounting, longitudinal performance evidence, and critically appraised, rather than simply aggregated, evidence capable of supporting high-confidence investment and policy decisions.