Calculation of chloride ion concentration in expressed pore solution of cement-based materials exposed to a chloride salt solution

摘要

To investigate the relationship between the chloride ion concentration of the expressed pore solution (c(e)) and the exposure solution (C-es) of cement-based materials exposed to a chloride salt solution, a calculation of the C-e, based on an electrical double layer (EDL) model was proposed. The C-e values were calculated using the proposed equations, applying the measured parameters: relative potential (delta psi(o)), dielectric constant (epsilon), porosity (P), bulk density (D), volume percentage (p(i)) of pores with diameter d(i). The calculations explain why C-e does not always equal to C-es. The results indicate that the expression method does not test the concentration of free chloride ions in the bulk solution (C-a(-) (b)) or the average concentration of the transportable chloride ions (Cana) in the pores. However, the ratio (C-r) of C-e to C-a(-) (b) and the relationship between C-e and C-ttr.a can be calculated to more accurately measure chloride ion migration in cement-based materials. (C) 2016 Elsevier Ltd. All rights reserved.