Half-cell corrosion potential is a non-destructive testing technique mainly used to assess the likelihood of steel corrosion in reinforced concrete.
Corrosion of steel reinforcement within concrete can create serious safety issues, as it directly reduces structural strength, weakens the concrete element, and shortens its service life.
When steel corrodes, the corrosion products typically occupy a larger volume than the original steel. As a result, the reinforcing bars expand, generating internal tensile stresses within the concrete. This leads to cracking, delamination, and gradual loss of strength.
Half-cell corrosion potential provides an effective and reliable method to estimate the probability of corrosion activity in reinforcement steel without causing any damage to the concrete structure.
The main parameter measured in this test is the electrical potential difference between a reference electrode—commonly a copper/copper sulfate electrode—and the embedded steel reinforcement.
The obtained values are then interpreted using guidelines such as ASTM C876 to determine the probability of corrosion activity.
Another important aspect of half-cell corrosion potential testing is its use in long-term monitoring. Since corrosion is a time-dependent process, tests conducted at regular intervals help engineers track changes in corrosion potential over months or even years.
Various agencies use half-cell corrosion potential testing as part of routine inspection programs for infrastructure such as bridges, tunnels, and marine structures.
Results from half-cell corrosion potential tests can also be compared with other data to support a more comprehensive durability assessment.
When combined with other inspection methods, this technique helps identify not only active corrosion zones but also possible underlying causes such as chloride ingress, carbonation, or moisture presence.
Ultimately, the importance of half-cell corrosion potential testing lies in its ability to deliver fast, cost-effective, and reliable insights into the electrochemical condition of embedded steel.
