Estimating the Electrical Conductivity of Cement Paste Pore Solutions From OH-,K+ and Na+ concentrations.
Estimating the Electrical Conductivity of Cement Paste
Pore Solutions From OH-,K+ and Na+ concentrations.
Snyder, K. A.; Feng, X.; Keen, B. D.; Mason, T. O.
Cement and Concrete Research, Vol. 33, No. 6, 793-798,
cements; electrical conductivity; pore solution;
transport properties; alkalis
A proposed method for estimating the electrical
conductivity of cement paste pore solution at 25 deg C
is based on the concentrations of OH-, K+ and Na+. The
approach uses an 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 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 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 error
by 55% at 2 mol/l. The significance and utility of the
proposed equation is discussed in the context of
predicting ionic transport in cement-based systems.