Innovative two-step synthesis design approach in developing vanadium incorporated low-carbon binder system

A novel two-step synthesis approach was developed to create a low-carbon C₂S binder system incorporating vanadium, utilizing thermodynamic modeling and subsequent experimental validation. The modeling identified 1 wt% V₂O₅ as the ideal dosage since excessive V₂O₅ led to Ca₂V₂O₇ generation, depleting CaO in C₂S phases. Additionally, 1400 °C was the optimal clinkering temperature for C₂S synthesis as higher temperatures favored C₃S formation while lower temperatures reduced the C₂S content. Experiments confirmed that clinkering at 1400 °C could produce high β-C₂S content in V₂O₅-doped binders, with V⁵⁺ ions stabilizing β-C₂S and inhibiting its transformation to γ-C₂S. Small amounts of Ca₂V₂O₇ formation during clinkering could also promote the V₂O₅ passivation. After 1-day carbonation, vanadium-dosed pastes prepared at 1400 °C possessed low porosity and dense morphologies, contributing to superior strength by forming CaCO₃ and gel phases. This approach offers a sustainable direction to maximize the performance of low-carbon binder systems by recycling heavy metal-derived solid wastes.