Effects of CuO doping on the calcination and hydration performance of alite-belite-ferrite-ye'elimite cement

Abstract

High-belite calcium sulfoaluminate cement (HBCSA) is a novel low-carbon cement, but the limited reactivity of belite (C2S) leads to gradual strength development. In this study, we developed an alite-belite-ferrite-ye'elimite cement (ABFY) incorporating C3S, and a high C4AF phase based on HBCSA. We explored the effects of CuO doping on the calcination and hydration properties of ABFY clinker. Various analytical techniques, including X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectroscopy, thermogravimetric analysis and derivative thermogravimetry, and nuclear magnetic resonance, were employed to investigate the effects of CuO doping on the sintering and hydration properties of ABFY clinker. The results indicated that CuO doping preferentially enters the ferrite phase, promotes liquid phase formation, and enhances the sintering of the C3S and C4A3$ phases, thereby improving hydration activity. However, exceeding a CuO content of 0.5% results in the decomposition of C4A3$ into C12A7 and the transformation of C3S into the M-type. Dissolved Cu during hydration combines with SO42‐, affecting the transformation and formation of AFm and AFt, resulting in deteriorated later-stage performance. ABFY with 0.5 % CuO exhibits favorable hydration activity.