Effects of curing time on the pore structure evolution and fracture behavior of CAC bonded alumina-spinel castables

作者：Liu, Wenjing; Liao, Ning^*; Nath, Mithun; Ji, Zixu; Dai, Yajie; Pan, Liping; Li, Yawei^*; Jastrzebska, Ilona; Szczerba, Jacek

来源：Ceramics International, 2022, 48(17): 25000-25010.

DOI：10.1016/j.ceramint.2022.05.153

• Alumina-spinel castables
• CAC cement
• Microporous feature
• Fracture behavior
• Acoustic emission

The present work investigated the pore structure evolution and fracture behavior of calcium aluminate cement (CAC)-bonded alumina-spinel castables treated at 110 and 1600 degrees C after curing at 25 degrees C for 1 day and 3 days. The pore structure and fracture behavior were characterized by mercury intrusion combined with micro-CT scanning and a wedge splitting test coupled with acoustic emission, respectively. The results showed that the hydration degree was enhanced by extending the curing time, and more hydrates were conducive to the generation of complex pore structures after drying. In comparison, the heat treatment at 1600 degrees C resulted in a substantial reduction in nano-sized pores, the 3 d sample obtained developed and complex micro-sized pores than 1 d sample. Therefore, specimens cured for 3 d had better hot modulus of rupture (HMOR) and thermal shock resistance compared to those cured for 1 d, which could be attributed to the induced tortuous microcrack propagation within the matrix and along the aggregate-matrix interfaces.