REACTIVE-TRANSPORT PARAMETERS ADJUSTMENT AND SENSITIVITY ANALYSIS: APPLICATION TO CONCRETE CARBONATION

摘要: The modelling of atmospheric carbonation of concrete material is an important part of the understanding of the phenomenological evolution of the geological disposal of low-and intermediate-level long-lived radioactive waste during the operating/reversibility period. Concrete carbonation is a complex process which involves the coupling of water flow (drying), transport in the aqueous and gaseous (mainly CO2) phases, dissolution of primary minerals (mainly portlandite, CSH and ettringite), and precipitation of secondary minerals such as calcium carbonate, other CSH phases (Thouvenot et al., 2013).A stochastic methodology was developed which aims at adjusting the reactive transport parameters of such systems thanks to the results of accelerated carbonation experiments at 20 C for different water content (corresponding to experiments at different relative humidities, HR)(Drouet, 2010). Indeed, a large number of simulation parameters used in calculations, either taken from the literature or based on “expert estimated” values, are fraught with significant uncertainty. It is, in particular, the case for parameters expressing the dependence of the diffusion coefficients with respect (a) to porosity ω and (b) to water saturation Sl (eg the Millington-Quirk law: b