A new arrangement of galvanic anodes for the repair of reinforced concrete structures

Christodoulou, Christian; Goodier, Chris I.; Austin, Simon A.; Glass, Gareth K.; Webb, John

doi:10.1016/j.conbuildmat.2013.09.062

Cited by 17 publications

(14 citation statements)

References 12 publications

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“…The data analysed in this study indicates that the design approach of an initial impressed current phase (50kC), followed by an ongoing galvanic phase for the remainder of the anodes design life, has been effective at preventing the initiation of reinforcement corrosion for up to about 8 years. This agrees with the majority of published work on the performance of hybrid anode systems and is a positive finding for the implementation of hybrid anodes as an alternative corrosion risk management technique in reinforced concrete structures [6,[9][10][11][12][13][14][15][16].…”

Section: Discussionsupporting

confidence: 87%

“…The hybrid anode is then disconnected from the temporary power supply and connected directly to the steel reinforcement, creating a galvanic cell, similar to a battery. This latter treatment phase continues for the remainder of the anodes' working life and provides a relatively low current to the steel reinforcement to maintain steel passivity [6,[13][14][15][16].…”

Section: Introduction 11 Hybrid Corrosion Protection Technologymentioning

confidence: 99%

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Hybrid anode concrete corrosion protection – independent study

Dodds

Christodoulou²,

Goodier

2018

Proceedings of the Institution of Civil Engineers - Constructio

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This study was the first of its kind which looked at long term performance of hybrid anode systems in reinforced concrete while also using a holistic approach to corrosion risk assessment. An independent appraisal of the site performance of DuoGuard™ Hybrid Anode™ systems was conducted on six bridges structures between 2013 and 2014. The hybrid systems had been installed on six reinforced concrete bridge structures in the UK between 2006 and 2013. The aim of the study was to investigate the efficiency of current design approach to meet the residual service life when the anodes are operating in the galvanic phase. This was achieved by analysing data on the general condition of the structures, the ongoing performance of the installed hybrid anodes, and assessing the overall corrosion risk of the structures. It was found that the six structures were generally in good condition, with low associated corrosion risks. More specifically, the areas protected by the hybrid anode systems had no associated defects or evidence of corrosion. This is a positive finding for the wider implementation of hybrid anode systems as an alternative corrosion management technique. The reinforcement in the protected areas remained predominately in a passive condition, with calculated corrosion rates below the ISO 12696:2012 recommended threshold of 2mA/m². On some occasions the corrosion rates exceeded the recommended threshold; in these instances, corrosion risk was assessed by analysing the trends of long term monitoring data (e.g. open steel circuit potentials) for signs of corrosion initiation. This study also makes recommendations on aspects of design approach in order to improve redundancy, functionality and robustness of hybrid anode systems.

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Section: Discussionsupporting

confidence: 87%

Section: Introduction 11 Hybrid Corrosion Protection Technologymentioning

confidence: 99%

Hybrid anode concrete corrosion protection – independent study

Dodds

Christodoulou²,

Goodier

2018

Proceedings of the Institution of Civil Engineers - Constructio

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“…This protection current is therefore controlled by the electrical resistivity of the concrete. Abundant literature can be found regarding the experimental illustration of the mutual polarization between sacrificial anodes and the reinforcing steel to be protected [1][2][3][4], where the authors compare the performances of several galvanic anodes and developed protocols for laboratory and on-site current monitoring.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical behavior of zinc layer anodes used for galvanic protection of steel in reinforced concrete

García¹,

Laurens

Panin³

2018

RILEM Tech Lett

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Steel corrosion is the most common reason for the premature deterioration of reinforced concrete structures. Consequently, cathodic protection of steel in concrete has been substantially developed during the past two decades -in particular galvanic protection. This consists of generating a natural macrocell corrosion system in which a sacrificial metallic anode (typically zinc) is used to apply a cathodic polarization to the corroding steel reinforcements, in order to mitigate or annihilate the corrosion kinetics. Although the general principle of cathodic protection is not questionable, the global design process can be significantly improved by increasing our knowledge of the electrochemical behaviours of the different components of the protecting system. Regarding zinc anodes in concrete, the literature is very scarce. The time evolution of such systems is also not rigorously addressed, ageing effects are systematically ignored and zinc anodes are usually considered as non-polarizable and inert over time. In this paper, the polarization response of a zinc layer anode (ZLA) in concrete electrolyte and its evolution over time are studied. The results show a rapid evolution of the ZLA behaviour once the protecting system is connected to steel reinforcements. Moreover, the characterization of ZLA provides relevant electrochemical properties for the numerical design of galvanic protection systems.

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“…An alternative criterion to the 100-mV depolarisation is verified to assess the performance of sacrificial anodes in patch repairs. According to this, parts of the steel bar away from the anode should have a significant polarization to at least a distance equal to half of the spacing between adjacent anodes (Christodoulou, Goodier, Austin, Glass, & Webb, 2014). The influence of the corrosion inhibitors in limiting the failure of patch repairs was also studied.…”

Section: Selection Of Repair Materialsmentioning

confidence: 99%

Performance of Concrete Patch Repairs: From a Durability Point of View

Eldho¹,

Nanayakkar²,

Xia³

et al. 2016

Proceedings of the 5th International Conference on the Durability of Concrete Structures

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Chloride contamination in reinforced concrete leads to the corrosion of steel bars. Concrete patch repairs are widely practiced as a remedial measure for the mitigation of such corrosion in reinforced concrete structures. The performance of the patch repairs was studied by various researchers in the past. The structural and material aspects of patch repairs have received more attention than the electrochemical consequences of patch repairs in past studies. But electrochemical changes could be the underlying cause for the failure of many patch repairs. This paper reviews the performance of patch repairs from a durability point of view. It covers the formation of incipient anodes, which are the new corrosion sites formed after a patch repair process. The prevailing corrosion mechanism at the incipient anodes is discussed. The performance of patch repairs when modified with corrosion inhibitors and sacrificial anodes is examined. The importance of the selection of repair materials from a durability point is highlighted considering the electrochemical consequences of patch repair.

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A new arrangement of galvanic anodes for the repair of reinforced concrete structures

Cited by 17 publications

References 12 publications

Hybrid anode concrete corrosion protection – independent study

Hybrid anode concrete corrosion protection – independent study

Electrochemical behavior of zinc layer anodes used for galvanic protection of steel in reinforced concrete

Performance of Concrete Patch Repairs: From a Durability Point of View

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