The potential role of the degradation products of cement superplasticizers on the mobility of radionuclides

Superplasticizers added into cementitious materials can degrade due to hydrolytic, thermal, radiolytic and microbial effects. Short-chain organic compounds such as acetate, phthalate, oxalate, phenol, urea, etc., have been confirmed as possible degradation products of superplasticizers. This work presents a review of the degradation process of superplasticizers and a thermodynamic study on the effect that model compounds considered as proxy for their degradation products have on the solubility of several radionuclides (Ni, Eu, U). Our results indicate that the complexation capacity of the proxy superplasticizers degradation products considered (i.e. acetate, phthalate, phenol and urea) towards Ni Eu and U is almost negligible in alkaline conditions, but relatively important in the near-neutral pH range.