Effect of curing time on the volume stability of corundum based castables bonded with calcium aluminate cement

摘要

The formation of CA(2) and CA(6) in calcium aluminate cement bonded castables lead to a large volume expansion, which probably results in the generation of cracks, thereby increasing slag penetration and decreasing mechanical strength. In this study, the influence of curing time on the dimensional stability of calcium aluminate cement bonded castables is considered to improve the volumetric stability. Phase compositions and morphologies evolution of matrix samples and castables are characterized by XRD and SEM, respectively. The results indicate that the volume stability of castables is greatly improved by increasing curing time from 0.5 days to 6 days after firing at 1600 degrees C. This can be attributed to two main reasons. First, the improvement in migration of CaO through extending curing time favors more uniform distribution of in situ CA(6). Second, more hydrates after dehydration creates more micro-pores, thereby providing space for the generation of in situ CA(6).