On the retardation mechanisms of citric acid in ettringite-based binders

This study aims to obtain insights into the retardation mechanism of citric acid in an ettringite-based binder from ladle slag and gypsum. The hydration kinetics phase assemblage were experimentally investigated thermodynamically modelled. Additionally, effects on synthetic ettringite studied further understanding interaction between this organic ligand crystal. Experimental results reveal that works as inhibitor ettringite's formation leading precipitation monosulfate gypsum; surface blockage by citrate effectively prevents leads overestimation thermodynamic model due kinetic barrier imposed ligand. Thermodynamic modelling suggests ettringite, monosulfate, aluminum hydroxide, strätlingite main hydrates binder, whereas intermixed C–(A–)S–H gel was observed instead strätlingite.