Superplasticisers are chemical admixtures used in the production of concretes and mortars. The use of superplasticisers for the packaging of low heat generating wastes has been proposed due to the operational advantages of reduced water content and increased fluidity of cementitious mixtures. However, concerns have previously been raised over the potential for superplasticisers to enhance the mobility of radionuclides during the post-closure phase of a geological disposal facility.
This report presents the results of experimental studies undertaken to gain greater insight into the likely effect of the latest class of superplasticisers, polycarboxylate ethers. The studies focussed on the effect of superplasticisers on the mobility and leaching of selected radionuclides through intact cement monoliths. The study also included verification of the effect of superplasticisers on radionuclides in cement-equilibrated waters for comparison against existing data available in the literature, the effect of gamma irradiation on the mobility and leaching from crushed superplasticiser-amended cement monoliths and porosity studies on superplasticiser-amended cement monoliths.