Thermal behavior and physical properties of castables during curing and drying-out are associated with their binding system. In this work, five alumina based (Al2O3>87%) castables with different combinations of binding materials, i.e., (1) CA cement (CA) + Reactive alumina (RA) + H2O; (2) high level addition of CA + Microsilica (MS) + H2O; (3) low level addition of CA + MS + H2O; (4) MS + Hydratable alumina + H2O and (5) MS + Magnesia + H2O, respectively, have been investigated on the flowability and thermal behavior during curing at room temperature, drying at 110°C and heating from 200°C to 1000°C at an interval of 100°C, in terms of water addition, vibration flow value, porosity, dehydration, explosion resistance, cold and hot bending strengths. Differences in dehydrating behavior and the mentioned properties have been revealed and correlated to the binding system.