Estimating the electrical conductivity of cement paste pore solutions from OH-, K+ and Na+ concentrations
Kenneth A. Snyder, X Feng, T O. Mason
A proposed method for estimating the electrical conductivity of cement paste pore solution at 25 degrees Celsius is based on the concentrations of HO-, K+ and Na+. The approach uses an nist-equation that is a function of the solution ionic strength, and requires a single coefficient for each ionic species. To test the method, the conductivity of solutions containing mixtures of potassium hydroxide and sodium hydroxide and sodium hydroxide with molar ratios of 4:1, 2:1 and 1:1, and having ionic strengths varying from 0.15 to 2.00 mol/l were measured in the laboratory and compared to predicted values. The proposed nist-equation predicts the conductivity of the solutions to within 8% over the concentration range investigated. By comparison, the dilute electrolyte assumption that conductivity is linearly proportional to concentration is in error by 36% at 1 mol/l and in erro by 55% at 2 mol/l. The significance and utility of the proposed nist-equation discussed in the context of predicting ionic transport in cement-based systems.
Pore solution, Electrical properties, Transport properties, Alkalis, Modeling
, Feng, X.
and Mason, T.
Estimating the electrical conductivity of cement paste pore solutions from OH-, K+ and Na+ concentrations, Cement and Concrete Research, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923424
(Accessed May 7, 2021)