Fine-grained high-strength concrete has already been tested extensively regarding its uniaxial strength. However, there is a lack of research on the multiaxial performance. In this contribution, some biaxial tests are investigated in order to compare the multiaxial load-bearing behaviour of fine-grained concretes with that of high-strength concretes with normal aggregate from the literature. The comparison pertains to the general biaxial load-bearing behaviour of concrete, the applicability of already existing fracture criteria and the extrapolation for the numerical investigation. This provides an insight into the applicability of existing data for the material characterisation of this fine-grained concrete and, in particular, to compensate for the lack of investigations on fine-grained concretes in general. It is shown, that the calibration of material models for fine-grained concretes based on literature results or normal-grained concrete with similar strength capacity is possible, as long as the uniaxial strength values and the modulus of elasticity are known. For the numerical simulation, a Microplane Drucker–Prager cap plasticity model is introduced and fitted in the first step to the biaxial compression tests. The model parameters are set into relation with the macroscopic quantities, gained from the observable behaviour of the concrete under uniaxial and biaxial compressive loading. It is shown that the model is able to capture the yielding and hardening effects of fine-grained high-strength concrete in different directions.

Le matériau composite agrégataire énergétique étudié a un comportement viscoélastique endommageable sensible à la pression de confinement et à la température. Ces travaux concernent la modélisation de l'anisotropie induite par endommagement avec deux objectifs principaux. Dans un premier temps, le caractère anisotrope de l'endommagement est mis en évidence expérimentalement. Des essais alternant tension et compression permettant d'observer l'effet unilatéral d'endommagement. Ensuite, un modèle de comportement est développé pour le matériau d'étude. Des modèles pertinents sont tout d'abord comparés. Le modèle le plus approprié est ensuite amélioré par l'ajout de mécanismes d'endommagement, d'effectivité du dommage et d'un mécanisme de plasticité. Les données expérimentales sont utilisées pour identifier les paramètres du modèle. Ce dernier a été ensuite implémenté dans un logiciel de calcul aux éléments finis (Abaqus / standard) sous la forme d'une procédure Fortran (UMAT). Différents types de chargements sont simulés et confrontés aux résultats expérimentaux. / An explosive aggregate material exhibits a visco-elastic behaviour with damage, internal friction and sensitivity to the confining pressure and temperature. This thesis focuses on the anisotropic elastic damage with unilateral effect. The first aim of this study is to highlight experimentally the anisotropic nature of the damage. Then, a new model is proposed for the studied material. This is achieved using a comparison of some relevant models in order to select the most appropriate among them. The selected model is then improved by adding unilateral effect mechanisms and plasticity. Experimental data is used to characterize the material behaviour and to determine the parameters of improved model. This model has been implemented in the finite element software (Abaqus / Standard) using Fortran procedure (UMAT) and then tested for different loads and compared with experimental results.