This paper presents a thermo-hydro-chemical model for concrete at high temperatures. Non-linear phenomena, heat and mass transfers, evolution of the phases constituting the porous medium are taken into account in a full three phases coupled analysis. The proposed model does not take into account mechanical aspects, i.e. the solid skeleton is considered as rigid. An experimental set-up and a numerical simulation are also presented. A hollow cylinder has been heated up to 523.15 K (250 degreesC) on the internal side and submitted to gas pressure/temperature measurements. A numerical simulation of the cylinder has been performed, showing a good correlation with the experimental observations. (C) 2003 Elsevier Ltd. All rights reserved.