The temperature-dependent properties of basaltic and limestone concrete as needed for predicting “Corium” melt propagation in concrete (elongation behavior, specific heat and degradation enthalpy, thermal diffusivity, and conductivity) are determined experimentally together with the chemical and physical reactions occurring in heated concrete. The determined oxidation potential of −335 kJ/mole for molten Corium interacting with the concrete is in accordance with the observed H2 generation due to the melt internal oxidation of zirconium, chromium, and iron. The liquefaction temperatures of the different concretes investigated are ∼1300 to 1400°C. The relatively high degradation enthalpy of basaltic and limestone concrete is the reason for the barrier effect of concrete against propagating molten Corium.