Transforming Industrial Waste into Low-Carbon Cement: A Multi-Criteria Assessment of Supplementary Cementitious Materials for Sustainable Concrete Design

The cement industry accounts for nearly 8% of global anthropogenic CO2 emissions, driven largely by energy-intensive clinker production. Valorising industrial and agricultural waste as Supplementary Cementitious Materials (SCMs) presents a viable mitigation strategy, aligning decarbonisation goals with circular-economy principles. This review employs a two-stage screening process and the Evaluation based on Distance from Average Solution (EDAS) method to assess 27 SCMs across technical, environmental, economic, and regulatory dimensions. The results establish a clear hierarchy: fly ash and metakaolin ranked highest, followed by ground granulated blast furnace slag, silica fume, and calcined clay. Life cycle assessment confirms these top-performing SCMs can reduce the global warming potential of cement production by 50–90% compared to ordinary Portland cement. While established SCMs like fly ash offer a balanced profile in durability, CO2 reduction, and cost, the framework also identifies regionally abundant materials such as steel slag, bagasse ash, red mud, and Rice Husk Ash (RHA), which possess significant potential but require further processing and standardisation. The findings underscore that material consistency, robust regional supply chains, and performance-based standards are critical for large-scale SCM adoption, providing a replicable framework to guide industry and policy stakeholders in accelerating the transition to low-carbon, waste-valorised cement technologies.