Reference: K.A. Snyder, X. Feng, B.D. Keen and T.O. Mason, Cement and Concrete
Research, **33** (6), 793-798 (2003).

(PDF Version of
Original Paper)
Reply to the discussion by C. Shi of the paper "Estimating the electrical conductivity of cement paste pore solution from OH, K^{+}, and
NA^{+} concentrations", Cement and Concrete Research, **35** (2),
421-422 (2005).
(PDF Version)

**Next:** Introduction

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## Estimating the electrical conductivity of cement
paste pore solutions from OH, K, and Na concentrations

K.A. Snyder X. Feng
B.D. Keen
T.O. Mason

Materials and Construction Research Division, BFRL, NIST

Department of Materials Science, Northwestern University

Building Research Association of New Zealand (BRANZ)

## Abstract

A proposed method for estimating the electrical conductivity of
cement paste pore solution at 25 ºC 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.

**Keywords:**
B-Pore Solution;
C-Electrical Properties;
C-Transport Properties;
D-Alkalis;
E-Modeling.

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