Calcium ion transport and leaching
The applicability of concrete as a solidifying barrier for the geological disposal of radioactive waste is being studied. Radioactive waste contains materials with long half-lives, so the period of stability required in design is several tens of thousands of years. This far exceeds the expected lifetime of the regular infrastructure. Calcium leaching over such an extremely long service life is one issue of crucial importance to be considered in the design and planning of such projects. The prediction of such phenomena over very long periods is diffi cult through experiments or accelerated tests alone. Experimental methods need to be combined with numerical analysis for more rational evaluations of performance, since methods of assessing barriers on a real-time scale are not appropriate. In feasibility studies as well as actual designs, numerical simulations that take a rational approach to account for mix proportion, types of constituent materials, structural dimensions and detailing are particularly useful. In other words, a theoretical scheme plays an essential role in linking accelerated tests with reality.