Title:
How concrete corrosion macrocells affect assessment and forecasting
Author(s):
Alberto A. Sagüés and Christopher L. Alexander
Publication:
Symposium Paper
Volume:
366
Issue:
Appears on pages(s):
66-87
Keywords:
corrosion, localized, macrocells, steel, rebar, concrete, measurement, polarization, impedance, modeling
DOI:
Date:
10/1/2025
Abstract:
Corrosion of steel in concrete involves interactions between net anodic and cathodic regions that may extend into the cm, m or multi-m range. Such broad macrocells conveniently help corrosion detection methods based on half-cell potential surveys. However, the macrocells can also complicate the interpretation of polarization measurements of corrosion rates, leading to over or under estimates depending on the chosen placement of the sensor electrodes. Corrosion macrocells can also make interdependent the corrosion initiation and propagation stages of
contiguous parts of a structure, by mutually affecting chloride threshold values and corrosion rates. Damage evolution forecasts change considerably when interdependence is taken into consideration, an issue of importance in creating next generation models. This paper addresses understanding by the corrosion in concrete community in a selection of these issues, and anticipates challenges to be resolved next.