The adaptation of an experimental protocol to the durability of cement engineered barriers for nuclear waste storage

Within the French context of nuclear waste disposal in deep geological formation, concrete will be used as the building material for structures as well as for engineered barrier systems (EBSs). With regard to the durability that is necessary to keep the disposal facilities safe and secure, the long-term behaviour of cement-based materials has to be modelled. To assess the long-term evolution of physical and chemical properties of concrete, it is necessary to perform short-term experiments in conditions allowing extrapolations. The aim of this project was to determine the variation of transfer properties (diffusivity, permeation) with hydrolysis/decalcification. To simulate the two time phases of the structure life according to the external conditions, transfer properties were examined through two decalcification tests: a dynamic (temperature between 20 and 80°C, under a hydraulic pressure drop from 2 to 10 MPa) and a static test (NH₄NO₃ attack). The results could be used as input data in the long-term modelling of the disposal confinement capacity.