Influence of gypsum additions on the hydration and properties of Belite-Ye’elimite-Ternesite clinker

Belite-Ye’elimite-Ternesite (BYT) clinker has many advantages compared to Portland cement (PC) clinker, including low sintering temperature and low carbon emission. In this study, we systematically investigated the hydration reaction of BYT clinker in the present of gypsum (CaSO 4 ·2 H 2 O) and compared the properties of BYT clinker with different gypsum additions. The results showed that the gypsum additions of 5 % and 10 % promoted the early exothermic reaction of BYT clinker. In the hydration process of BYT clinker, an inhibitory effect of gypsum was found on the hydration of belite. In addition, the mechanism for the influence of gypsum additions on the hydration behavior of BYT clinker was illustrated that when the content of gypsum was more than 15 %, the production of AFm (C 6 A$H 12 ) and strätlingite (C 2 ASH 8 ) was limited due to the massive formation of AFt (C 6 A$ 3 H 32 ). The addition of gypsum improved pore size distribution and compressive strength. Especially, the 1-day and 56-day compressive strength of BYT clinker increased by 41.6 % and 47.4 %, with gypsum additions of 5 % and 20 %, respectively.