Influence of barium oxide on the composition and performance of alite-rich Portland cement

The clinker composition and performance of alite-rich Portland cement with different contents of barium oxide and calcium barium sulfoaluminate (abbr. C_2·75B_1·25A₃S¯) were investigated by orthogonal testing. The results show that alite and C_2·75B_1·25A₃S¯ mineral can coexist in a clinker system. The addition of barium oxide is of benefit to increase the content of C_2·75B_1·25A₃S¯, and it can also activate the belite and promote the formation of alite at low temperature. The optimal silica modulus, iron modulus, lime saturation factor and content of C_2·75B_1·25A₃S¯ are 2·3, 1·4, 0·94 and 4% respectively, and the proper content of barium oxide is 1·8%(by weight). The compressive strength of this cement prepared under these conditions reaches 52·3, 78·4 and 106·5 MPa at 3-day, 7-day and 28-day curing ages, which shows excellent performance of mechanical strength. The compositions, structures and performances of the clinker were analysed by means of X-ray diffraction, scanning electron microscopy–energy dispersive spectroscopy and metallographic microscope.