Concrete and cement are used in constructions as well as in conditioning of waste inrepositories for radioactive waste. It is well known that in the hyperalkaline conditions (pH > 12) of standard cement pore fluids, there is potential for deleterious effects upon the host rock and other EBS materials, notably bentonite, in geological repositories. Low pH cements are beginning to be considered as a potential alternative material that may address some of these concerns. SKB has (as the Finnish Posiva and the Japanese NUMO) defined a pH limit ≤ 11 for cement grout leachates.
