Refractory Castables: II, Some Properties, and Effects of Heat-Treatments

Differential thermal analyses were made and weight losses were determined up to 1000°C. for a domestic and an imported high-alumina hydraulic cement after hydrating. Refractory castables were prepared in the laboratory with these two cements and fire-clay brick and flintclay aggregates. Compressive, transverse, and tensile strengths of these castables were obtained after heating 4,8, and 12 months at 300°C. and at other temperatures up to 1350°C. for shorter periods of time. Sixteen commercial brands of castables were tested for sieve analysis, P.C.E., and flow, on the material "as received". The three types of strengths of the sixteen castables also were determined after treatments at 95% relative humidity and after heating at temperatures up to 1350°C. Some information on porosity and structural and linear changes after the heat-treatments was obtained.