UCLA

Belitic calcium sulfoaluminate cement (BCSA) can mitigate the environmental impact of cement manufacture. It has less embodied CO2 than Portland cement, significant strength within four hours of mixing, and better durability versus calcium sulfoaluminate cement (CSA), functioning as a standalone binder. This study examined class C fly ash, unclassified lignite fly ash, flue gas desulfurization (FGD) waste ash, and paper recycling waste as alternative supplementary cementitious materials (SCMs) in BCSA to reduce embodied CO2 while maintaining mechanical performance by utilizing the unique chemistry of BCSA. Set time, flow, shrinkage, and compressive strength characterized SCMs in mortars, while pastes’ hydration and microstructure were evaluated via Rietveld refinement, thermogravimetry, isothermal calorimetry, and electron microscopy. The compressive strength of concrete containing FGD waste ash, the best-performing SCM, was measured. Carbon intensity quantifies embodied CO2 per unit strength: FGD waste ash consistently reduced carbon intensity versus control specimens.