Influence of lithium salt on the performance of calcium sulfoaluminate cement

This work explores the effect of lithium salt on the properties of calcium sulfoaluminate (CSA) cements where different proportions of gypsum are added. Experiments comprising hydration heat release, setting time, mechanical strength and hydration products are studied. The results showed that the addition of Li2CO3 significantly accelerates the early hydration and decreases the setting time of CSA cement whatever the gypsum content added to cement. When the content of Li2CO3 increases, the setting time decreases accordingly. When gypsum is incorporated, the compressive strength development of the mortars with Li2CO3 suffers a decrease, especially after one day of hydration. When the amount of gypsum increases, the later strength of the mortars with Li2CO3 exhibits no obvious decrease. The addition of Li2CO3 inhibits C4A3 (S) over bar hydration of CSA cement comprising 10% gypsum at 1 day but promotes ettringite formation after 28 days of hydration. In contrast, the presence of Li2CO3 promotes C4A3 (S) over bar hydration of CSA cement without gypsum addition.