Effects of characteristic hydrates on the pore structure and fracture behavior of CAC bonded alumina-spinel castables

作者：Liu, Wenjing; Liao, Ning^*; Nath, Mithun; Li, Yawei^*; Dai, Yajie; Pan, Liping

来源：CONSTRUCTION AND BUILDING MATERIALS, 2023, 389: 131736.

DOI：10.1016/j.conbuildmat.2023.131736

• Alumina-spinel castables
• Characteristic hydrates
• Pore structure
• Fracture behavior
• Wedge-splitting test

In the present study, the characteristic hydrates (CAH10, C2AH8, and C3AH6) were evaluated at individual curing temperatures (10 degrees C, 25 degrees C, and 40 degrees C), and the influences of these characteristic hydrates on the pore structure and fracture behaviors of alumina-spinel castables were systematically investigated. The results revealed that the specimens cured at 10 and 25 degrees C showed refined and complicated pore structures (higher fractal dimension) after treatment at 1600 degrees C owing to a higher dispersion of CaO and closely interlocked CA6 structures. In comparison, the enhanced hydration degree at 40 degrees C (mostly C3AH6) had no positive effect on the formation of nano-pores. Consequently, the generation of plate-like C2AH8 at 25 degrees C contributed to higher bonding strength after demolding and firing. The optimized microstructures facilitated cracks propagation within the matrixes and along aggregate-matrix interfaces, improving the toughness of castables and obtaining optimal comprehensive properties.