This paper presents an experimental and thermo-hydro-chemical-mechanical numerical analysis of concrete at high temperatures, aiming at the definition of a law describing the evolution of intrinsic permeability. The evaluation of heat and mass transfers, evolution of the phases composing the porous medium, and mechanical performances of concrete are taken into account in a full three phases coupled analysis. An experimental set-up and a numerical simulation are then presented. A hollow cylinder has been heated up to 523.15K (250 degreesC) on the internal side and subjected to gas pressure/temperature measurements; the experience has been then simulated by means of a numerical code. The analysis has allowed for the definition of an original relationship describing intrinsic permeability evolution. Finally, the law has been validated measuring the actual value of intrinsic permeability on heated concrete.