Characterisation of steel corrosion and matrix damage in reinforced mortar combining analytical, electrical and image-based techniques

Journal article, 2025

Characterising steel corrosion at the steel-concrete interface and linking it to concrete damage is challenging
due to limitations of current non-destructive techniques. This study combines electrical resistance measurements,
full-field image-based analyses and analytical techniques to comprehensively characterise steel corrosion
and damage in small-scale specimens.
X-ray and Neutron Computed Tomography of two reinforced mortar samples, before and after accelerated
corrosion, were used to examine corrosion morphology, interfacial voids, and estimate volumetric strain in
the corrosion layer. Inductively Coupled Plasma Mass Spectrometry was employed to measure iron isotope
concentrations in water surrounding the specimens.
The results revealed delayed transport of corrosion products relative to mortar cracking. The volumetric
expansion coefficients of corrosion products (3.84 and 3.90) align with previous research, and the risk of pitting
corrosion correlated with the void size. Overall, the measurements obtained through the various techniques
closely aligned with visual observations, providing a robust dataset for calibrating corrosion models.