Waste-Derived and Supplementary Cementitious Materials as Low-Carbon Binders: Data-Driven Evaluation of Strength, Durability and Global Warming Potential

The concrete industry is a major source of global carbon emissions, largely due to Portland cement (OPC) production. Supplementary cementitious materials (SCMs), many originating as industrial by-products or waste streams, can reduce these emissions while supporting material circularity. This study compiles published (as at June 2023) data on compressive strength, durability, and global warming potential (GWP) for eight SCMs, integrating these metrics into a combined performance index (CPI) where data coverage permits. Of the eight SCMs, GBFS, fly ash, and silica fume had sufficient data for robust CPI calculation, although a value was also derived for waste marble powder, based on limited data. GBFS above 49% replacement achieved the strongest performance, reducing GWP by up to 62% while maintaining strength and durability comparable to OPC, while fly ash at 30–49% replacement also performed well. Comparison of cement paste and concrete results revealed limited correspondence, indicating paste data are not reliable predictors of concrete performance. These findings highlight the potential of high performing SCMs to lower emissions and improve resource efficiency, but SCM adoption alone will not achieve net zero, underscoring the need for complementary strategies including low-carbon binders and alternative materials.