In the case of a radioactive waste disposal, concrete containment structures must be studied over extended periods during which it is necessary to account for a possible degradation by calcium leaching due to on-site water. This phenomenon affects the microstructure of concrete and then is coupled with the mechanical behaviour of concrete. The effect of leaching on the static behaviour and then the possible influence of cracks on leaching will be considered. But there is also a possible coupling due to tertiary creep. In this case, failure occurs eventually. And finally, a probabilistic approach is used with the leaching and tertiary creep models to evaluate the lifetime of a concrete structure subjected to chemical and mechanical loading.