Micromechanical modelling of damage induced by delayed ettringite formation
Résumé
Delayed ettringite formation (DEF) is a pathology that induces concrete swelling and cracking. Factors contributing to DEF have been identified experimentally, but on the modelling side the link between DEF-induced expansion and the evolution of concrete and mortar physical properties has been less studied. A multi-scale poromechanical model is introduced which features a description of DEF induced mortar damage by progression of microcracking. The model considers mortar as a three phases material that is constituted of cement paste, sand and micro-cracks. The Mori-Tanaka scheme is used to homogenise the poroelastic properties of the mortar. The loading parameters are a macroscopic strain and an expansive free strain induced by DEF in cement paste. Damage progression by micro cracking is accounted for by a Griffith-like energy criterion. The model allows to link the DEF-induced expansion at both the microscopic and macroscopic scales to the loss of stiffness of the mortar. A comparison of the model to experimental data on mortars formulated with CEM I cement and natural silica sand is carried out.
Domaines
Génie civilOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
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