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Estimation of Pore Solution Conductivity

The purpose of this form is to provide an estimate of the electrical conductivity (S/m) of the pore solution in a concrete based on the mixture proportions and achieved degree of hydration.

It is assumed that 75 % of the sodium and potassium initially present as oxides in the cement-based materials will be released into the pore solution. In the presence of silica fume, more alkalies are absorbed by the products of the pozzolanic reactions and "free" alkali ions are further reduced. This calculation only considers the alkali ions and their accompanying hydroxides and not others such as chlorides, etc.


Bentz, D.P., "A Virtual Rapid Chloride Permeability Test," Cement and Concrete Composites29 (10), 723-731, 2007.

Snyder, K.A., Feng, X., Keen, B.D., and Mason, T.O., "Estimating the Electrical Conductivity of Cement Paste Pore Solutions from OH-, K+ and and Na+ Concentrations," Cement and Concrete Research33 (6), 793-798, 2003.

Mixture Proportions

Material Mass (kg or lb) Na2O content (mass %) K2O content (mass %) SiO2 content (mass %)
Water Not applicable Not applicable Not applicable
Cement Not applicable
Silica fume
Fly ash
Slag Not applicable

Estimated system degree of hydration (%):

Hydrodynamic viscosity of pore solution relative to water:

Curing: Saturated Sealed

Estimated pore solution composition (M):




Estimated pore solution conductivity (S/m):

Effective water-to-cement ratio: Free alkali ion factor:

Created May 1, 2017, Updated November 25, 2019