Modelling of the Volume Effects Related to the Unixial Behaviour of Concrete. From a Discontinuous to a Macroscopic Approach

The modelling of the cracking behaviour of cementitious composites can be viewed as one of the actual major stakes in civil engineering. Although models are more and more sophisticated and relatively appropriate to represent the macroscopic mechanical behaviour, they are not usually fully pertinent for describing the complex localised or diffused multi-cracking processes arising in such materials and eventually their possible couplings with other physical or chemo-physical phenomena. Difficulties are essentially lying in combining the descriptions of microscopic mechanisms at the level of the material and their impacts on the macroscopic behaviours at the structural level, thus describing the whole range of scales (and one can note that complexities are even larger if the heterogeneous character of the material and the size effects it induces [1] are taken into account). The goal is then to develop models allowing obtaining the finest information on the cracking processes but keeping a robust and reliable description of the macroscopic mechanical behaviour.