dA quantification of electrical double layer influence on chlorides electrodiffusion process in concrete is presented. The modelling is carried out at a microscopic scale of a concrete capillary. The study, which is based on electrical magnitudes engendered by transfers (density of current, potential, space charge density and conductivity), shows the generation of an induced electrical field opposed to the external field imposed. Simulations of the distribution of these parameters through a pore with variable section have shown that when the pores are small, more the opposition of the induced field to the electrodiffusion flux is efficient. Furthermore, the study reveals the existence of two time scales: - tau (D) characterizes the transfer process, it depends mainly on the nature of the chemical species present in pore solution. - tau (c) corresponds to the charge establishing time at the interface capillary wall-pore solution. It depends mainly on the electrical double layer capacity. (C) 2001 Elsevier Science Ltd. All rights reserved.