E-FEM predictions of concrete failure mechanism under triaxial compression from tensile rupture modelling at the meso-scale: comparison with X-ray tomography
Résumé
This paper presents the capabilities of a mesoscopic numerical model to predict the deformation and fracture process of concrete under different triaxial compression levels. The mesoscopic scale is explicitly represented by three phases; the macro-porosity, the aggregates and the mortar matrix. An implementation of the Embedded Finite Element method (E-FEM) using a set of two discontinuities enables the modelling of both the heterogeneous nature and the brittle behaviour of concrete at this scale. Conducted after a tomographic x-ray in-situ experimental campaign, the mesostructure representation required by the E-FEM model is extracted from the 3D images, avoiding the use of a morphological model. After its calibration in simple tension, the predictive ability of the model is tested under multiple loading paths in compression ranging from 0 to 15 MPa of confining pressure. A direct comparison of the numerical predictions is made in terms of macroscopic responses, failure mechanisms and failure patterns against the experimental results. The study shows that the model exhibits emerging macroscopic features, such as compressive strength and complex failure patterns, despite the simple phenomenological law driving the meso-scale tensile failure. The numerical predictions are in good agreement with the experimental observations, demonstrating the pronounced impact of the meso-scale heterogeneities of concrete on its failure mechanisms.
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