Effects of lithium carbonate on performances of sulphoaluminate cement-based dual liquid high water material and its mechanisms

Abstract

Sulphoaluminate cement-based dual liquid high water material has some defects, such as longer setting time, higher bleeding capacity and lower strength and so on. In order to improve its defects, the effects of lithium carbonate on those properties were studied, and its mechanisms were analyzed through micro testing, including hydration heat tests, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The results show that the setting time of high water material becomes shorter, its bleeding capacity becomes lower and its compressive strength becomes higher when the content of lithium carbonate increases from 0%, 0.1%, 0.2%, 0.3% to 0.5%. Lithium carbonate helps to accelerate the hydration process of high water material at early stage and to increase the amount of the accumulated heat of hydration heat. The testing results of the XRD, the DTA-TG, and SEM show that the ettringite is the main hydration product, and the amount, the shape and the microstructure of ettringite are all different as the lithium carbonate increases.