Galvanic Protection of Reinforced Concrete via Chloride Extraction
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Solution Overview
Problem
Galvanic protection techniques for reinforced concrete are limited by the modest currents generated by sacrificial anodes, which are insufficient for protecting steel reinforcements from pitting corrosion in chlorinated environments, and existing methods for removing chloride ions are costly and inefficient.
Innovation Solution
A method involving drilling holes in the concrete structure, inserting decontamination electrodes and an electrolyte, applying a current to attract and remove chloride ions, and then sealing sacrificial anodes to provide galvanic protection, using reusable tool anodes that are not consumed during the decontamination phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic protection is applied using sacrificial anodes, then the steel reinforcements are protected from corrosion, but the current generated is insufficient (modest currents not exceeding 2 mA per m²) to effectively remove chloride ions and prevent pitting corrosion in chlorinated environments
Solution Approach 1:
The patent applies preliminary action by performing chloride extraction using impressed current cathodic protection (ICCP) before installing the galvanic protection system. This preliminary treatment removes chloride ions from the concrete matrix and creates a low-chloride zone around the reinforcements, enabling the subsequent galvanic system to function effectively even with its limited current output. The decontamination phase prepares the environment so that the sacrificial anodes can provide adequate protection despite their modest current generation capability.
2Object-affected harmful factors
If chloride extraction is performed using traditional impressed current methods with generators, then chloride ions are removed from the structure, but the process is long and expensive to implement
Solution Approach 1:
The patent applies partial action by focusing the decontamination effort only on the immediate vicinity of the reinforcements rather than treating the entire concrete structure. The sacrificial anodes are positioned strategically to create localized zones of low chloride concentration around the steel bars. This targeted approach removes chlorides from the critical areas where pitting corrosion is most likely to occur, achieving sufficient protection without the time and cost penalties of complete structure decontamination.
3Object-affected harmful factors
If chloride extraction is performed using traditional impressed current methods with generators, then chloride ions are removed from the structure, but the implementation cost is high
Solution Approach 1:
The patent applies self-service by using the sacrificial anodes themselves as both the protection mechanism and the decontamination tool. The anodes are installed in a preliminary configuration that enables them to deliver sufficient current for chloride extraction during an initial treatment phase. After decontamination, the same anodes continue to provide galvanic protection. This eliminates the need for separate expensive ICCP equipment and reduces overall project costs while achieving effective chloride removal.
4Ease of operation
If sacrificial anodes are used for galvanic protection, then no generator or current regulation system is needed, but the current supplied is limited by the corrosion rate of the anodes
Solution Approach 1:
The patent applies preliminary action by performing chloride extraction before installing the final galvanic protection system. This preliminary decontamination phase creates a low-chloride environment around the reinforcements, which reduces the chloride concentration gradient that would otherwise drive corrosion. As a result, the sacrificial anodes need to supply less current to maintain protection, effectively extending their service life and ensuring adequate protection despite their limited current generation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces chloride ions around steel reinforcements without consuming the sacrificial anodes, allowing for efficient galvanic protection in a low-chlorine environment at a lower cost, extending the lifespan of the protection system.
Implementation Method 1
electrically connecting the negative terminal of a current source to the armatures and the positive terminal of the current source to each decontamination electrode; activate the current source; removing the electrolyte and each decontamination electrode
Implementation Method 2
Galvanic cathodic protection is based on a principle similar to cathodic protection, but the current supplied results from the corrosion of the anode itself connected to the armatures. This is then referred to as a sacrificial anode. The anodes are made of an easily oxidizable metal such as zinc, aluminum, magnesium or alloys.
Implementation Method 3
engaging a decontamination electrode and an electrolyte in at least one of the holes
Data Source
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Figure 5
AI summary
The invention relates to the galvanic protection of a concrete structure (10) comprising metal reinforcements (12). Holes (15) are previously made in the structure, for receiving sacrificial anodes. Before arranging said sacrificial anodes, decontamination electrodes (16) and an electrolyte are inserted into the holes in order to carry out a decontamination phase wherein the negative terminal of a power supply (18) is electrically connected to the reinforcements of the structure and the positive terminal of the power supply is electrically connected to the decontamination electrodes. Once the power supply has been activated for a certain amount of time in order to attract the chloride ions to the decontamination electrodes and the electrolyte, the electrolyte and the decontamination electrodes are removed from the holes (15) and the sacrificial anodes are sealed therein and then electrically connected to the reinforcements.