Modelling of coupled multifield problems in concrete by means of porous media mechanics

A mathematical and numerical model to predict the non-linear behaviour of concrete as a multiphase porous material is proposed. The model can be usefully applied to several practical cases: evaluation of concrete performance in the high temperature range, e.g. during fire, to early stages of maturing of massive concrete structures, to shotcrete in tunnelling, and to durability processes (e.g. leaching/carbonation). All the important phase changes of water and chemical reactions, i.e. adsorption-desorption, condensation-evaporation, and hydration-dehydration, skeleton dissolution/carbonation as well as the related heat and mass sources or sinks are considered. Changes of the material properties caused by temperature and pressure changes, concrete damage, carbonation, leaching, fresh concrete hardening, as well as coupling between thermal, hygral, chemical and mechanical phenomena are taken into account. This model further allows to incorporate sorption hysteresis. Some relevant applications of the model will be shown in this work.