Abstract
The effects of varying Li2CO3 additions on the hydration kinetics of a ternary CSA-OPC-anhydrite system were investigated. The presence of Li led to increased ye'elimite and C3S dissolution as well as accelerated ettringite precipitation. Excessive additions however resulted in heavily decreased ye'elimite dissolution and hydration kinetics after the initial period as evidenced by heat-flow-calorimetry and in-situ XRD. Pore solution analysis showed that the decreased ye'elimite dissolution can be linked to remarkably high Ca/Al-ratios which correspond to the induction period in CSA based systems combined with retarding agents. The early precipitated silicon incorporating hydrate phase in these systems is either straetlingite or a zeolitic phase. The high Li-addition led to a dissolution of these phases in favor of C-S-H precipitation. Consequently, the formed hydrate phase assemblage was changed from ettringite, AH3 and straetlingite or Ca-zeolite in the reference and low Li2CO3 system to ettringite and C-S-H precipitation in the highly dosed Li system.
Published Version
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