Comportement mécanique des modèles contenant des granulats légers

Résumé Nous avons schématisé le béton léger par un modèle élémentaire plan constituté d'un granulat léger dans une matrice. Nous avons étudié expérimentalement le comportement mécanique de ce modèle sous des sollicitations de compression monoaxiale et biaxiale.

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Summary An elementary plane model consisting of a circular lightweight aggregate bonded in a matrix is used to represent lightweight concrete. The mechanical behaviour of this model is examined in uniaxial and biaxial compression, then compared with that of models where the singularity is first a hole and then an aggregate whose rigidity is practically infinite compared with that of the matrix. The localization of cracks and the cracking and failure fields in models in the R₂ space of applied stresses show that the mechanical behaviour of models containing lightweight aggregates is very close to that of models where singularities consist of holes. Research reveals that the crack and failure limit states of models in biaxial compression are not independent of the value of the principal intermediate stress. Criteria of the Tresca and Caquot type cannot be applied to the overall model and consequently to lightweight aggregate concrete.