Feasibility of a non-contact corrosion technique to detect the corrosion rate of rebar in cementitious materials

The need to establish an external electrical connection to rebar during field corrosion testing presents a significant challenge for reinforced concrete structures, owing to the required damage to the concrete cover. Thus, there is an urgent need to develop a Non-contact Corrosion Technique (NCT) to overcome this limitation by measuring rebar corrosion without an electrical connection. The feasibility of NCT was verified by measuring polarization resistance of rebar in simulated solutions and comparing with conventional electrochemical measurements. The pulse current played a crucial role in the feasibility of NCT, and the NCT could not provide an accurate evaluation of passivated rebar in simulated solutions. Moreover, the high pulse current impaired the electrochemical stability of the rebar. Also, the feasibility of NCT was verified for rebar embedded in mortars subjected to long-term chloride attack, and a more accurate estimation of the corrosion rate was obtained compared with that in simulated solutions.