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The article presents a numerical finite element study of fluid leakage in concrete. Concrete cracking is numerically modelled in the framework of a macroscopic probabilistic approach. Material heterogeneity and the re- lated mechanical effects are taken into account by defining the elementary mechanical properties according to spatially uncorrelated random fields. Each finite element is consid- ered as representative of a volume of heterogeneous ma- terial, whose mechanical behaviour depends on its own volume. The parameters of the statistical distributions defining the elementary mechanical properties thus vary over the computational mesh element-by-element. A weak hydro-mechanical coupling assumption is introduced to represent the influence of cracking on the variation of transfer properties: it is assumed that the mechanical cracking of a finite element induces a loss of isotropy of its own permeability tensor. At the elementary level, an ex- perimentally enhanced parallel plates model is used to re- late the local crack permeability to the elementary crack aperture. A Monte Carlo-like approach allows to statisti- cally validate the numerical method. The self-consistency of the proposed modelling strategy is finally explored through the numerical simulation of the hydro-mechanical splitting test, recently proposed by authors to evaluate the real-time evolution of the transfer properties of a concrete sample under loading

This paper concerns the relationship between compressive, tensile and flexural creep behaviours related to the same concrete. Experimental tests and a numerical simulation are performed in the scope of this work. The main conclusion of this study is that due to the strong scale effect related to the tensile and bending creep behaviours of a “standard” concrete mix design, it is not possible to simulate numerically (with classical Kelvin‐Voigt chains) the bending creep behaviour of that type of concrete knowing the compressive and tensile creep behaviours obtained using the specimen geometries normally used in laboratories.

The description of cracks in concrete is crucial when dealing with life expectancy of structures such as dams, nuclear power plants vessels, waste (nuclear or not) storage structures, tunnels, etc. The main objective is not only to describe the growth of a preexisting flaw, but also to predict the genesis and formation of cracks in an initially flaw-free structure (at least at the macroscopic level) subjected to tension. The presented paper provides a macroscopic model for tensile cracking (i.e., a model adequate for describing the behavior at the structure level), capable at the same time of providing information on the local response (i.e., cracks). The model takes into account scale effects as well as the heterogeneous nature of concrete via appropriate, experimentally validated, size effect laws and via a statistical distribution of mechanical properties. Results are provided and validated via a 2D comparison with an original experimental test.

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