Abstract: Three electrochemical methods，i.e. chronoamperimetric (CA), cyclic voltammetric (CV) and AC impedance methods have been proposed to replace the method of AASHTO proposed by ASTM. It has been shown that CA and CV methods are far simpler and easier than that of AASHTO with the same precision and reliability. AC impedance method will give information about resistance and diffusion of ions in pore solution which are correlated to chloride permiability．

Key words: chloride permeability, electrochemical methods, AC impedance