Chloride penetration monitoring in reinforced concrete structure using carbon nanotube/cement composite

• CNT/cement composite could be used as chloride sensor in concrete structure.
• Conductivity of the CNT/cement composite was influenced mainly by the sodium chloride content.
• A CNT content in the composite was an important factor on the chloride monitoring accuracy.

A novel non-destructive method of monitoring chloride penetration in reinforced concrete structures prior to corrosion is proposed. By measuring the change in the electrical characteristics induced by chloride in cement composites containing carbon nanotubes (CNTs), chloride penetration in the structures could be monitored in real time. To evaluate the feasibility of this method, cement composites containing various amounts of CNTs and sodium chloride were fabricated and their electrical characteristics were measured. Although the conductivity of the composite without CNTs fluctuated as a result of both reinforcement and moisture content, that of the composites with CNTs was seldom influenced by these factors, and the conductivity generally increased with increasing chloride content. The chloride content in the composites was estimated via regression analysis based on the electrical characteristics, implying that the CNT/cement composite could be used as a sensor for chloride penetration monitoring.