Work

Influence of SiO2 content on the CA2–CA6 transformation and mechanical behavior of calcium aluminate cement

Year: 2026

Type: article

Abstract: Silica is an essential component for improving the workability and fluidity of calcium aluminate cement (CAC). Therefore, phase and volume changes have been measured as a function of silica content and temperature, and investigated the resulting mechanical stability. XRD measurements of specimens containing 0.26-4.0 wt.% SiO 2 sintered at 1500 °C showed that the CA 6 fraction increased from 9.8 to 28.6 wt.% with increasing SiO 2 . Phase fraction and three-point flexural strength were further evaluated after three thermal cycles at 1500 °C. The 2.0 wt.% SiO 2 composition exhibited the highest initial strength but experienced significant degradation after cycling. In contrast, the 4.0 wt.% SiO 2 specimen demonstrated improved strength after cycling due to enhanced CA 6 formation. The CA 6 phase impeded crack propagation through deflection and bridging, while SiO 2 -induced liquid phases facilitated densification. These results demonstrate that adjusting the SiO 2 content is an effective approach to improve the long-term thermal stability of CAC-based refractories.

Source: Open Ceramics

DOI: 10.1016/j.oceram.2026.100918