THE EFFECT OF SUPERPLASTICIZERS ON THE PROPERTIES OF GAMMA IRRADIATED CEMENT PASTES

Considering the safety criteria on radioactive waste disposal, all materials within the repositories usually have to meet very strict requirements. Low and intermediate level waste can be immobilised in cement composites for its well-proven properties, however there are gaps in the knowledge relating to the interaction of organic species, such as superplasticizers, with the cement paste and the irradiation stability of the final composite. The presented work studies the effects of gamma irradiation on the mechanical properties of cement pastes incorporating high amounts of two kinds of superplasticizers. In addition to this, temperature development due to the irradiation inside the pastes was studied in order to recognise potential temperature gradients. The obtained results showed insignificant changes of bulk density and scatter in values obtained by non-destructive methods. Destructive testing, however, revealed a positive effect of the irradiation on both the flexural and compressive strength of the studied pastes. The overall temperature changes were within 2C, having no significant effects on the properties of the pastes.