Early identification of infrastructure materials degradation can provide significant economic benefits to the management and maintenance of a structure. For reinforced concrete structures, there is a significant delay between corrosion initiation and visible evidence of deterioration. The recommended maintenance approach can vary for structures with only localized versus widespread deterioration.
Half-cell potential measurements are commonly used as a non-destructive technique (NDT) to assess the likelihood of reinforcement corrosion within a concrete structure. The results of this technique are dependent on a range of factors – including construction and environmental factors – and skilled interpretation is required. One common standard to interpret half-cell potential measurements is ASTM C876, however there is other published experimental data which offers alternative criteria.
In this paper the theoretical basis of the technique, along with a practical method for taking measurements in the field, is described. Limitations and sources of error are identified. A review of the published literature is undertaken to identify theoretical and experimental data which can be used as criteria when assessing half-cell potential measurements.
Finally, the authors present data from additional investigative works for a pre-stressed reinforced concrete structure, and contrast the results of half-cell potential measurements, concrete chloride concentration with observed reinforcement corrosion.