Electrical Conductivity and Chloride Ingress in Hardened Cement Paste

Abstract

The transport properties of hardened cement paste (HCP) have been investigated in many studies; the AC impedance method (ACI) is a non-destructive technique employed for this purpose and has been used in investigations of the elec-trical characteristic and mass transport properties of HCP. However, there are relatively fewer studies investigating chloride ingress in HCP and using the ACI. In this study, the relationship between the electrical conductivity measured by the ACI and chloride ingress was investigated. Backscattered electron image analysis and mercury intrusion porosimetry and water porosity were used to measure the pore structure of HCP, and the chloride ingress depth was measured by an electron probe microanalyzer. There was a high correlation between the porosity and conductivity and between the conductivity and diffusion coefficient of the chloride ions in HCP. This implies that the diffusion coefficient of chloride ions could be estimated by the conductivity measurements.