Etude du séchage du béton : application aux colis de déchets radioactifs
Drying behavior of concrete : application to nuclear waste packages
EL TABBAL
Type de document
THESE
Langue
anglais
Auteur
EL TABBAL
Résumé / Abstract
The overall objective of this thesis is to provide a new valid poromechanical model that can be used to study the risk of cracking of the concrete shell caused by the restriction of drying shrinkage. revious modelling works based on a classical Thermo-Hydro-Mechanical (THM) formalism have shown the need of a better understanding of the drying behavior of concrete, in particular for what concerns the hydromechanical coupling. As a matter of fact, the THM models based on the poromechanical works of Biot, Terzaghi and then Coussy et al. (2003), are proven to be only valid for a relative humidity higher than 50% (Wyrzykowski et al., 2017). In this thesis, we propose a new poromechanical model that extends and adapts those models to a lower relative humidity. This result is obtained by introducing the mechanism of adsorption of water molecules on the pores surface and its effect on the hydro-mechanical coupling. Apart from the hydromechanical coupling, the drying kinetics of the concrete impacts the kinetics of shrinkage. The existing models of water transfer are examined and discussed with respect to their applicability to high-performance concretes (such as the F44Adj). Hence, two chapters of this thesis are devoted to the water retention phenomenon and to the transfer properties of the concrete. Finally, material properties are necessary to accurately model the drying behavior of the F44Adj concrete. For this reason, EDF has established an experimental program in order to obtain the data necessary to calibrate the transfer parameters as well as to validate the proposed poromechanical model. Hence, a large section of each chapter is dedicated to the description and analysis of experimental results, then to calibration of the model parameters.
