Effect of Coarse Aggregate on Thermal Spalling Resistance of Refractory Castables for Steel Ladle Linings

摘要

The panel spalling test was used to examine the effect of coarse aggregate size on thermal spalling resistance of refractory castables for steel ladle linings. With an increase in the coarse aggregate content of a castable, the aggregate distribution can range from uniformly dispersed to densely packed, with tangential contact and the growth of clusters. The minimum aggregate content that will initiate cluster-forming decreases when smaller aggregate is used in a castable.With increasing coarse aggregate content in a castable, the thermal spalling resistance gradually increases up to an optimum, then decreases, because of formation and growth of clusters, to its lowest level, where clusters have completely grown up to one large solid cluster over the whole specimen. With a further increase of coarse aggregate content, the thermal spalling resistance increases again due to development of a densely packed structure of coarse aggregate grains.