Pore solution electrical conductivity estimations in Portland cement pastes: experimental and theoretical insights

As concrete chloride assessment methodologies are expensive and time-consuming, tests based on concrete resistivity have emerged as a cheap and quick solution. The formation factor has recently appeared as an alternative to evaluate the transport related properties of concrete. The formation factor is a physical property representing the ratio of the concrete's pore solution electrical conductivity to the material's electrical conductivity. In this study, from data published by RILEM, who collected experimental data from related literature, some of the key parameters of the pore solution have been analyzed. Results showed the statistical analysis of the experimental pore solution evolution for ionic species, some models proposed for the ionic concentrations and the evolution of the electrical conductivity. Additionally, models from the cement composition were obtained to predict the pore solution concentration. Finally, results of simulations using the NIST platform “Estimation of Pore Solution Conductivity” were compared to the experimental data available, finding a very good precision and accuracy of the model; however, some adjustment factors were proposed here to improve its accuracy.