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Place Amphitéâtre 1Z28, bâtiment Nord, ENS Paris-Saclay
Image correlation for the study of cementitious materials affected by internal swelling reactions
Concrete, through its interaction with the environment, can develop internal swelling reactions leading to the formation of mesocracks and macroscopic swelling. When combined with an anchorage, this pathology affects the load-bearing capacity and stiffness of the structure. However, this behaviour is often linked to local deformation mechanisms that are difficult to access using conventional experimental methods.
This thesis presents an experimental study on scaled models of electricity pylon foundations, with the aim of identifying and quantifying the mechanisms induced by alkali–silica reaction under pull-out loading.
A new experimental set-up has been designed to perform in-situ pull-out tests on 1/50 scale foundations in-situ within an X-ray tomograph. The development of a method combining computed tomography and digital volume correlation makes it possible to track the degradation of the material and to measure the kinematics of the structure.
The proposed methodology allows the quantification of damage mechanisms, heterogeneous swelling, and interfacial debonding between the anchor and the foundation, induced by both the chemical reaction and the mechanical loading. These observations provide valuable insight into the relationship between the structural response and the internal development of the pathology.
In addition, finite element model updating and integrated digital image correlation methods have been developed and applied to three-point bending tests in order to assess the evolution of the mortar’s mechanical properties.
Implementation on finite element analysis software is thus possible to simulate the pull-out tests and discriminate between models.
Composition du jury :
- PÉRIÉ Jean-Noël: Rapporteur et Examinateur, Professeur des universités, Université de Toulouse
- SAOUMA Victor, Rapporteur et Examinateur, Professeur émérite, Université du Colorado
- MAIRE Éric, Examinateur, Directeur de recherche CNRS, INSA Lyon
- MULTON Stéphane, Examinateur, Professeur des universités, INSA Toulouse
- PIJAUDIER-CABOT Gilles, Examinateur, Professeur des universités, Université de Pau et des Pays de l'Adour