Characterisation of the Barrier Performance of Cements

Portland and modified Portland cements are useful matrices for solidification and storage of wastes . Concrete containing, cement is likely to be introduced into the repository. The further use of cement as an engineered barrier reduces materials incompatibility problems. Cement has a high internal pH and maintains a high buffering reserve of alkalinity. This in turn, reduces the solubility of many radionuclides. The source of the immobilisation (chemical. physical) is Sensitive to nuclide Species: Sorption and precipitation are the main binding mechanisms. The conditioning action of cement could affect the performance of other engineered barriers. The deterioration of cements is discussed. Areas of research needs are highlighted.