Corrosion Mechanisms and Monitoring in Reinforced Concrete Structures

Steel reinforcement in concrete benefits from the high alkalinity of the cement pore solution, which initially forms a passive film on the metal surface. This protective passivation can be compromised when aggressive agents such as chloride ions penetrate the concrete cover or when carbonation lowers the pore pH, triggering depassivation and enabling anodic dissolution of steel. The corroding metal produces expansive products that crack the surrounding concrete, accelerating damage through increased permeability. Understanding the mechanisms—from ion transport through the porous matrix and electrochemical kinetics at the steel–concrete interface to the influence of moisture and oxygen availability—is essential to predict service life. Monitoring techniques, whether based on half-cell potential mapping, resistivity measurements, electrochemical impedance spectroscopy or advanced sensor arrays, yield critical data for early detection of corrosion and validation of predictive models. Recent advances integrate kinetic modelling with non-destructive evaluation to support probabilistic durability assessments and optimise maintenance strategies, promoting sustainability and resilience of infrastructure worldwide.

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Corrosion Mechanisms and Monitoring in Reinforced Concrete Structures publication trend

The graph below shows the total number of articles in corrosion mechanisms and monitoring in reinforced concrete structures across all publications each year (not limited to Nature Index journals).

Technical terms

Corrosion initiation: the breakdown of the passive oxide film on steel, often triggered by chloride ingress or carbonation.

Chloride threshold: the critical concentration of chlorides at the steel surface required to induce depassivation and active corrosion.

Half-cell potential: an electrochemical measurement of steel reinforcement potential relative to a reference electrode, used to identify active corrosion zones.

Electrical resistivity: a measure of the concrete’s ability to impede ionic flow, inversely related to its moisture content and permeability.

Non-destructive technique (NDT): methods for assessing material condition without altering or damaging the structure, such as electrochemical impedance spectroscopy.

Diffusion coefficient: a parameter quantifying the rate at which ions migrate through concrete pore networks under concentration gradients.

References

1. Mechanisms and kinetic model for steel corrosion in unsaturated cementitious materials. npj Materials Degradation (2024).
2. A probabilistic interpretation of corrosion state through half-cell potential and electrical resistivity measures: The Flaminio Bridge in Rome. Case Studies in Construction Materials (2024).
3. Challenges and opportunities in corrosion of steel in concrete. Materials and Structures (2018).