EPJ Web of Conferences
Volume 56, 2013International Workshop NUCPERF 2012: Long-Term Performance of Cementitious Barriers and Reinforced Concrete in Nuclear Power Plant and Radioactive Waste Storage and Disposal (RILEM Event TC 226-CNM and EFC Event 351)
|Number of page(s)||9|
|Section||Session 1: Physical, Chemical and Mechanical Behavior: Physico-chemical Effect|
|Published online||11 July 2013|
Link between microstructure and tritiated water diffusivity in mortars
1 CEA, DEN, DPC, SECR, Laboratoire d’Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette, France
2 Paris Est University, Navier Institute (UMR8205 CNRS/ENPC/IFSTTAR), 2 allée Kepler, F-77420 Marne La Vallée, France
3 EDF R&D, Moret sur Loing, France
Ions and radionuclide diffusivity in concrete is one of the most important factors that determine service life and safety assessment of cement based structures in nuclear power plants and radioactive-waste repositories. Apart from the influence of cement paste microstructure, the presence of aggregates may have an impact on transport properties of the material. The well-known interfacial transition zone, denoted by ITZ, is created near the aggregates and characterized by a greater porosity. The goal of this study is to investigate the competition between the more diffusing ITZ zone and the less diffusing aggregates. To this end, several series of tritiated water diffusion tests are conducted on mortars characterized by different water-to-cement ratios and sand volume fractions. In parallel, microstructure of these materials is explored by mercury and water porosimetry. It was observed that at low sand content (0% – 50%), diffusion properties of mortars are dominated by aggregates dilution effect. At 60% sand, diffusion increases significantly suggesting that percolation’s pores threshold has been reached. Results indicate also that sand particle size distribution has a great impact on the diffusivity of mortars.
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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