Coupling effect of the connected pores and pore solution on chloride ion migration in cement-based materials

In this study, a new method for determining the connected pore porosity, tortuosity and constrictivity was developed based on AC impedance tests. The effects of the pore factor x1, pore solution factor x2, pore-pore solution factor x3 and coupling factor x on the non-steady state chloride ion migration coef-ficient (Dm) were evaluated. The results indicated that x1, x2, x3 and any single parameter did not have good correlations with Dm, and x had an excellent linear correlation with Dm. This confirms that the coupling effect of the pores, the pore solution and their interaction control the chloride ion migration pro -cess. The contributions of x1, x2 and x3 to Dm accounted for 54.44%, 13.05%, and 31.27%, respectively. Therefore, the migration of chloride ions can be controlled to a large extent by reducing x1 and x3, which can be obtained through a reduction in the connected porosity and the accompanying reduction in S. This means that the connected pores play a decisive role in controlling the migration of chloride ions in cement-based materials, whose conductivity can be used for quickly determining the extreme value of the chlorine-related durability. (c) 2021 Elsevier Ltd. All rights reserved.