A new procedure to measure effective molecular diffusion coefficients of salts solutions in building materials

Abstract

The aim of this work is to present a mathematical and experimental formulation of a new simple procedure for the measurement of effective molecular diffusion coefficients of a salt solution in a water-saturated building material. This innovate experimental procedure and mathematical formulation is presented in detail and experimental values of effective molecular diffusion coefficient of sodium chloride in a concrete sample (w/c = 0.45), at five different temperatures (between 10 and 30 C) and four different initial NaCl concentrations (between 0.1 and 0.5 M), are reported. The experimental results obtained are in good agreement with the theoretical and experimental values of molecular diffusion coefficient presented in literature. An empirical correlation is presented for the prediction of effective molecular diffusion coefficient over the entire range of temperatures and initial salt concentrations studied.