Abstract
This study investigates the use of a conductive cement composite containing carbon nanotubes (CNTs) and carbon fibres (CFs) as a reference electrode for corrosion monitoring in reinforced concrete. For comparison, stainless-steel reference electrodes were also prepared. Both CNT/CF cement composite and stainless-steel electrodes were immersed in a 10% NaCl solution for three months to simulate a chloride-rich marine environment. The open circuit potential (OCP) of both reference electrodes was measured against a standard silver/silver chloride electrode (SSCE) over time. Two reinforced mortar samples and one reinforced concrete sample were tested under different exposure conditions. In Experimental Program 1, a mixed-in NaCl contamination approach was employed by incorporating NaCl into cylindrical concrete samples at concentrations ranging from 0% to 1.2% by binder weight. Corrosion current was measured using the linear polarization resistance (LPR) method with the three reference electrodes. In Experimental Program 2, mortar blocks were immersed in a NaCl solution following the NT Build 443 standard, and corrosion initiation was monitored through OCP measurements over time. In Experimental Program 3, reinforced concrete blocks with varying cover depths were subjected to rapid chloride ingress using a 30 V potential for 24 hours, following the NT Build 492 standard. The OCP of embedded rebars was then measured using all three electrodes. Results indicate that the CNT/CF cement composite electrode maintained a stable potential (~-220 mV vs. SSCE) regardless of chloride exposure, while the stainless-steel electrode exhibited potential variation over time. Corrosion monitoring using CNT/CF electrodes demonstrated reliable OCP measurements, faster stabilization, and consistent correlation with SSCE, confirming their suitability for long-term monitoring in chloride-exposed structures.
Keywords
CNT/CF cement composite, stainless-steel, open circuit potential, corrosion current, corrosion.
DOI
10.5703/1288284318103
Recommended Citation
Emiru, Michael Tesfaye and Hyeongki, Kim, "Application of CNT/CF Cement Composite Sensor for Corrosion Monitoring in Chloride-Exposed Reinforced Concrete" (2025). International Conference on Durability of Concrete Structures. 3.
https://docs.lib.purdue.edu/icdcs/2025/ddm/3
Application of CNT/CF Cement Composite Sensor for Corrosion Monitoring in Chloride-Exposed Reinforced Concrete
This study investigates the use of a conductive cement composite containing carbon nanotubes (CNTs) and carbon fibres (CFs) as a reference electrode for corrosion monitoring in reinforced concrete. For comparison, stainless-steel reference electrodes were also prepared. Both CNT/CF cement composite and stainless-steel electrodes were immersed in a 10% NaCl solution for three months to simulate a chloride-rich marine environment. The open circuit potential (OCP) of both reference electrodes was measured against a standard silver/silver chloride electrode (SSCE) over time. Two reinforced mortar samples and one reinforced concrete sample were tested under different exposure conditions. In Experimental Program 1, a mixed-in NaCl contamination approach was employed by incorporating NaCl into cylindrical concrete samples at concentrations ranging from 0% to 1.2% by binder weight. Corrosion current was measured using the linear polarization resistance (LPR) method with the three reference electrodes. In Experimental Program 2, mortar blocks were immersed in a NaCl solution following the NT Build 443 standard, and corrosion initiation was monitored through OCP measurements over time. In Experimental Program 3, reinforced concrete blocks with varying cover depths were subjected to rapid chloride ingress using a 30 V potential for 24 hours, following the NT Build 492 standard. The OCP of embedded rebars was then measured using all three electrodes. Results indicate that the CNT/CF cement composite electrode maintained a stable potential (~-220 mV vs. SSCE) regardless of chloride exposure, while the stainless-steel electrode exhibited potential variation over time. Corrosion monitoring using CNT/CF electrodes demonstrated reliable OCP measurements, faster stabilization, and consistent correlation with SSCE, confirming their suitability for long-term monitoring in chloride-exposed structures.
