Experimental and modeling studies of the link between microstructure and effective diffusivity of cement pastes

ABSTRACT This paper presents a review of complementary experimental and modeling studies of the link between microstructure and diffusivity of cement pastes. These studies were performed in the framework of the workgroup Concrete Engineering Barrier headed by Andra. Knowledge of the link between microstructure and diffusivity is needed to run properly the coupled chemical, transport and mechanical models used to assess the long term behavior of concrete in deep repository conditions. The first part of the paper is devoted to a description of the porous texture of ordinary Portland cement pastes, in particular obtained using Transmission Electronic Microscopy. The second and third parts are respectively dedicated to the presentations of an analytical method and a 3D numerical one, both of them aimed at linking microstructure and diffusivity of cement pastes.