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Abstract: The aim of this study was to investigate the interaction between macrocell and microcell corrosion processes in a concrete column exposed to tidal conditions simulated by sinusoidal water-level changes. Macrocell corrosion currents were continuously measured for 19 weeks along the column height using coupled multi-electrodes (CMEs). Cumulative corrosion damage and the morphology of corrosion products were analysed using X-ray microCT, SEM, and Raman spectroscopy. The results showed complex patterns of anodic and cathodic activity, including sinusoidal and switch-like current behaviour, which depended on the water level position and exposure time. Corrosion typically initiated in the upper tidal zone, but the most corroded individual electrode was located near mid-tide. Damage distribution was influenced by both microcell and macrocell corrosion, where microcell corrosion was most prevalent in the high-tide area, whereas macrocell activity contributed to corrosion damage in several exposure zones. SEM and Raman analyses confirmed a correlation between corrosion type and corrosion product morphology. An attempt was made to explain the recognised corrosion patterns along the vertical position and the ratios between microcell and macrocell corrosion on individual electrodes were esti- mated. Additionally, new questions were raised that highlight the complexity of corrosion processes under tidal cycling and emphasise the need for further research into these phenomena.
Keywords: corrosion, coupled multi-electrode array, simulated tiding, reinforced concrete, macrocell corrosion
Published in DiRROS: 12.01.2026; Views: 159; Downloads: 99
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Abstract: This dataset supports the investigation of long-term corrosion behaviour of steel in alkali-activated mortars (AAMs), a promising alternative to ordinary Portland cement (OPC). It contains experimental data collected over a one-year exposure period in which steel-reinforced AAMs were subjected to cyclic wetting and drying with a chloride-containing solution. The dataset includes results from three AAM compositions based on fly ash, slag, and metakaolin. Corrosion monitoring was performed using two advanced techniques: coupled multi-electrode array (CMEA) sensors for measuring partial currents, and electrical resistance (ER) sensors for quantifying steel cross-section loss. Additionally, the dataset contains imaging data from X-ray computed microtomography (microCT), as well as photographs of the steel reinforcement after exposure. This comprehensive dataset provides the foundation for the research paper Characterization of steel corrosion in alkali-activated mortars using advanced techniques (https://doi.org/10.1016/j.cscm.2025.e05165) and enables further studies on corrosion processes in AAMs, supporting the development of advanced monitoring approaches for alternative cementitious materials.
Keywords: korozija, alkalijsko-aktivirani materiali, mreža sklopljenih elektrod, električni uporovni senzor, rentgenska računalniška mikrotomografija, vizualna analiza
Published in DiRROS: 09.06.2025; Views: 627; Downloads: 574
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Abstract: In this study, the influence of voids on corrosion process at the steel-concrete interface was investigated, as the exact influence of these features on corrosion processes under various environmental conditions is not entirely understood. Coupled multi electrode arrays and electrical resistance probes were implemented to monitor the evolution of corrosion under cyclic exposure to chlorides and carbonation. MicroCT was used to determine the location and volume of corrosion damage. It was found that, in most cases, corrosion damage initiated outside the voids. During initiation and the early propagation phase, the steel beneath the voids rarely participated in the redox reaction. In following phases, various kinds of corrosion evolution were observed. Specific corrosion mechanisms were proposed and discussed to explain these corrosion processes.
Keywords: microtomography, corrosion, coupled multi-electrode array, steel-concrete interface
Published in DiRROS: 06.06.2024; Views: 1230; Downloads: 1148
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Abstract: One of the potential alternatives to Ordinary Portland Cement (OPC) are Alkali-Activated Materials (AAMs). The service life of reinforced concrete structures greatly depends on the corrosion resistance of embedded steel reinforcement. Due to the wide range of AAMs and their diverse properties, corrosion processes of steel in these materials are relatively unknown. Corrosion monitoring methods or their interpretations in certain cases cannot be directly transferred from the ones for OPC materials. The chemical compositions of pore solution in different AAMs influence the results of electrochemical measurements and their interpretations. Within this research, three different alkali-activated mortar mixes were prepared, based on fly ash, slag or metakaolin. Pore solutions were extracted from each mortar andchemical analysis was acquired. Different electrochemical corrosion measurements were performed on steel submerged to synthetic pore solutions. In parallel, ordinary carbon steel reinforcing bar was installed in the same types of alkali-activated mortar mixes. Specimens were exposed to wet/dry cycles with saline solution and periodic measurements of electrochemical impedance spectroscopy (EIS) were performed. Measured parameters in both systems were analysedand compared. It was concluded that electrochemical measurements in pore solutions can provide basic overview on corrosion behaviour in different AAMs environments. Periodic EIS measurements enabled monitoring of corrosion initiation and propagation on steel reinforcement in AAMs, although the information on the corrosion type is missing. Interpretation of results depends on visual analysis of corrosion damages after the end of exposure, providing information on corrosion type and intensity. The continuation of research on corrosion monitoring techniques will be performed by using Electrical Resistance (ER) sensors and Coupled Multi-Electrode Array (CMEA) sensors.
Keywords: corrosion, alkali-activated mortars, pore solution extraction, electrochemical corrosion techniques, visual analysis
Published in DiRROS: 22.01.2024; Views: 1559; Downloads: 1024
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Abstract: In the case of a two-part container for spent nuclear fuel, consisting of an iron-based inner structure with a copper coating, the potential perforation of copper through minor damage may result in intensive galvanic corrosion between copper and steel. The present work focuses on the corrosion of steel galvanically coupled to copper and exposed to a slightly saline environment under oxic conditions. The electrochemical processes on individual electrodes were monitored by coupled multielectrode arrays (CMEAs). The CMEAs were either in contact with groundwater saturated with bentonite or immersed in groundwater only. Very high galvanic corrosion currents were detected between carbon steel and pure copper in the early oxic phase. Additionally, the use of CMEAs further made it possible to monitor the distribution of cathodic currents around the steel electrode, which behaved anodically. Various microscopy and spectroscopy techniques were applied to identify the modes of corrosion and the type of corrosion products present at the end of the period of exposure.
Keywords: copper, steel, bentonite, Aspö groundwater, coupled multi electrode array, electrochemical properties, Raman analysis, corrosion
Published in DiRROS: 16.11.2023; Views: 1874; Downloads: 948
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