Explicit modelling of cracking induced by drying shrinkage
Résumé
The prediction of the durability of a concrete structure is closely linked to the prediction of cracking at its early age. Indeed, differential drying between the surface and the core of the structure leads to a heterogeneous stress state and can induce significant micro-cracking at the surface [1, 2]. These micro-cracks will impact not only the mechanical properties but also the permeability of the structure [3]. In this study, a sequential analysis is proposed to represent the drying evolution and the corresponding cracking pattern. First, Finite Elements calculations are used to perform drying simulations and obtain drying shrinkage strains. Then, a beam-particle model is applied to obtain the deformation shape and the cracking pattern. Indeed, this Discrete Elements model is designed to describe discontinuous mediums and thus can naturally predict crack initiation as well as their propagation and closing [4]. This analysis allows us to accurately model the cracking induced by drying shrinkage. The dried specimens can then be subjected to various numerical tests in order to analyse the impact of drying effects on concrete mechanical properties – such as the Young modulus, the tensile and compressive strength and the fracture energy. The influence of shrinkage on the cracks formation and re-closure appearing during the mechanical loading can also be investigated. These numerical studies will benefit from an experimental campaign performed in parallel.