Portland Cement at the Crossroads: Environmental Imperatives and Pathways to Sustainable Production

The cement industry is indispensable for global infrastructure development, yet poses severe environmental challenges, accounting for 8–10% of anthropogenic CO₂ emissions, 12–15% of industrial energy use, and extensive natural resource depletion. This review systematically examines the sector’s ecological and health impacts, revealing that 40–50% of emissions stem intrinsically from clinker chemistry and kiln combustion, while co-pollutants (NOₓ, SO₂, PM) exacerbate climate change, biodiversity loss, and respiratory diseases. To address these dual crises, we synthesize emerging sustainability strategies across the concrete lifecycle. Key findings demonstrate that supplementary cementitious materials (SCMs) like fly ash or slag can reduce CO₂ by ≤1 kg per kg of cement replaced while enhancing durability through microstructural refinement. Complementary approaches include alternative/recycled aggregates, conserving natural resources, fossil fuel substitution with waste-derived alternatives, and mix optimization, minimizing binder content. Though technoeconomic barriers persist for carbon capture and storage (CCS) and recycled concrete aggregates, regulatory frameworks emphasizing life-cycle assessment can accelerate adoption. Critically, no single solution suffices; achieving sectoral decarbonization requires policy-driven integration of these strategies within a circular economy paradigm.