Cathodic protection of reinforced concrete facilitated by using CNT-CF/cement-based auxiliary anode

In this article, the carbon nanotube-carbon fiber (CNT-CF)/cement-based composite served as a novel auxiliary anode in the form of overlay for the cathodic protection of reinforced concrete (RC) was proposed. The effect of CNT content and age on the conductivity of CNT-CF/cement-based composite was firstly analyzed. After applying the CNT-CF/cement-based composite, the effectiveness of cathodic protection on the reinforcement was evaluated by the corrosion potential and corrosion current, respectively, as measured by Tafel polarization and half-cell potential methods. For comparison, finite element simulation was adopted to calculate the corrosion potential and corrosion current. It showed that the resistivity of CNT-CF/cement-based composite monotonously decreased with increasing content of CNT up to 2 wt.%. When the CNT content was 0.5 wt.%, the resistivity of the composite reached the minimum value of 22.3 Ω·cm. The resistivity for all the groups decreased with increasing age in the first 7 days. Both the experimental and simulated results showed that the CNT-CF/cement-based auxiliary anode improves the cathodic protection effectiveness for RC.