2:45 PM - 3:00 PM
[3C09] Numerical analysis of geochemical degradation of concrete during groundwater infiltration: Effect of redox-oxidation condition
Keywords:cementitious materials, reactive transport modelling, oxidation-reduction potential, layered double hydroxide
In engineered barrier system of low-level radioactive waste, time-dependent variation of groundwater chemistry for cementitious near-field is important for performance assessment of physical containment attained by metallic container. We have been developing an assessment methodology of concrete degradation due to groundwater infiltration under various redox-oxidation conditions. Numerical analysis targeted at concretes consisting of OPC and limestone aggregates has been conducted. As a result, contrasting dissolution behaviour between AFm- and AFt-phases has been observed: (1) in the case of oxidizing groundwater, AFm-phase leached out before complete dissolution of AFt-phase; (2) in the case of reducing groundwater, AFm-phase leached out after complete dissolution of AFt-phase. This result suggests that numerical settings for AFm- and AFt-solid solutions should be given sufficient attention.