Analysis of cementitious pore solutions with very high time resolution by coupling cross flow filtration and ICP-OES

Pore solution analysis is a powerful tool for understanding reactions that occur during the cement hydration. Crossflow filtration of cement paste provides more detailed insight into reactions and reaction pathways compared to standard methods for gaining pore fluid. In particular, the large time resolution for the analysis enables the characterization of fast processes like adsorption kinetics and hydration reactions of aluminate phases in unprecedented detail. A direct comparison of the crossflow filtration results with those obtained using a filter press showed no significant difference in pore solution composition. With this method, it is possible to analyze the complex reaction patterns of cementitious reactions in great detail during the first minutes of hydration. This is especially important for chemically admixed systems. [Display omitted] •A continuous filtration method enhances time resolution of pore solution data compared to conventional dead-end filtration.•This filtration method was applied to different retarders evaluating the adsorption kinetics on cement.•Pore solution data with a high time resolution was gained to analyze the development of the ion composition over time.•The combination of continuous pore-solution and in-situ calorimetry allowed conclusions on the mode of action of retarders.