ICP-OES method for the characterization of cement pore solutions and their modification by polycarboxylate-based superplasticizers

Pore solution compositions dictate the kinetics of cement hydration. Their characterization can therefore provide essential insight into the rate at which cement phases hydrated. One of the most widely used techniques to characterize pore solution composition is ICP-OES. However, cement literature generally overlooks the fact that high accuracy from this technique can only be obtained if proper accounting for matrix effects is carried out. We first present a new method for such a technique, demonstrating that limits of quantification down to 34 times lower than the ones generally reported can be obtained. This method is applied to the study of the early hydration of admixed cement pastes. In particular, we highlight the formation of nanoparticles that may have different origins. The formation can be expected to have important consequences on the working mechanisms of some chemical admixtures. (C) 2016 Elsevier Ltd. All rights reserved.