Role of pore pressure on cracking and mechanical performance of concrete subjected to drying

Abstract Cement based material structures have to be managed over long periods. However, they are exposed to numerous loadings and present time-dependent deformations. In addition, the material is a porous medium in which pore pressure has an impact on macroscopic behaviour. The goal of this study is to better forecast the long term behaviour of cement based materials taking into account interactions between loads, time-dependent deformations and pore pressure. To do so, a previous model developed by the authors is extended to implement the impact of pore pressure on mechanical behaviour. Two applications are run on a mature ordinary concrete. The damage state is clearly dependent of the mechanisms involved in the modelling. Considering pore pressure allows to find damage depth more accurate regarding experimental evidences. After a calibration of one test (at h r  = 45%), we were able to predict the behaviour of other tests, with an underestimation of 10% on one sample where h r changed. Interestingly, it was not manageable to use the same Biot parameter for the drying shrinkage and the mechanical modelling. As a result, by changing drastically the mechanical behaviour, the modelling of pore pressure is important to accurately assess the cracking state.