Current Cathodic Protection Research Articles

Combine merits of both sacrificial and impressed current cathodic protection in one system to mitigate chloride-induced corrosion in reinforcement concrete

Abstract The protection of Egyptian reinforcing concrete infrastructures from corrosion is a pressing and critical task for construction engineering and industry, particularly in coastal locations. The primary aim of this case study is to integrate the advantages of both sacrificial anode cathodic protection (SACP) and impressed current cathodic protection (ICCP) in a single cathodic protection (CP) system and to use the new system in Alamein New Place near the Mediterranean sea (Egypt). The results showed that the new cathodic protection system is running very well to protect the concrete iron bars from corrosion. With the passage of time, the protective system’s efficiency and stability improve. During 30 days, the zinc anode’s potentials remain much more negative, indicating that the zinc anode can retain strong electrochemical activity for an extended length of time. The application of the CP method decreases the corrosion rate of rebar steel in concrete samples over time, according to electrochemical impedance spectroscopy (EIS).

Characteristics of Calcareous Films Formed by Using Pulse Electrodeposition Method in Natural Seawater

Due to the characteristics of seawater as the most environmentally corrosive electrolyte solution, using the cathodic protection method while taking it into consideration widely prevails in offshore and underwater structures. Cathodic protection is type of method polarizing the surface of the corrosive metal to reduce the corrosion rate. When this principle is applied, the ionic component that is dissolved in seawater can be deposited partially when Mg(OH)2 and CaCO3 compound to coat an electrodeposited film on the metal surface. These electrodeposition films are called as ‘calcareous deposits,’ which act as a physical barrier and they function to reduce the density of the cathodic protection current, which eventually leads to an anti-corrosion effect. However, these films, on the other hand, are influenced to large extent by the condition of surrounding environment when formed as well as the condition of deposits components, which are neither dense nor uniform. In this study, the pulse electro-deposition method was applied to make calcareous deposits film in natural seawater. The components and structures are, then, analyzed by using Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The amounts of the formed film, adhesion, and corrosion resistance were evaluated individually to prove its effectiveness. This study validated the effectiveness of the pulse electrodeposition method and considered the formation mechanism of the calcareous deposits film through analysis and evaluation results. In addition, this study also confirmed the potential for improving the performance of existing calcareous films that showed weak durability by controlling the pulse current.

The effect of pulse current cathodic protection on cathodic disbondment of epoxy coatings

For coated pipelines with cathodic protection, cathodic delamination has been judged as the main reason of coating delamination. This work aims to use the pulse current cathodic protection (PCCP) to mitigate the coating cathodic delamination. Cathodic delamination tests, electrochemical impedance spectroscopy and wire beam electrode method (WBE) were used to study the effect of PCCP on the mitigation of coating disbondment. The results show that PCCP could successfully retard the cathodic delamination rates of organic coatings. Under different cathodic protection potential, the delamination area of the coating protected using PCCP is much smaller than that using direct current cathodic protection. With the increasing pulse frequency and duty ratio, the mitigation effect decreases. Within the range of pulse frequency from 5 Hz to 500 Hz and duty ratio from 0.1 to 0.9, the results of cathodic delamination tests and WBE tests indicate that when the cathodic potential is −1.5 V, the mitigation effect reaches the maximum with the pulse frequency of 5 Hz and the duty ratio of 0.1. PCCP alleviates cathodic delamination of coating mainly by intermittently shifting the surface polarization potential to positive direction and reducing the consumption of cathodic reaction charge.

Cement-Based Thermoelectric Device for Protection of Carbon Steel in Alkaline Chloride Solution

The thermoelectric cement-based materials can convert heat into electricity; this makes them promising candidates for impressed current cathodic protection of carbon steel. However, attempts to use the thermoelectric cement-based materials for energy conversion usually results in low conversion efficiency, because of the low electrical conductivity and Seebeck coefficient. Herein, we deposited polyaniline on the surface of MnO2 and fabricated a cement-based thermoelectric device with added PANI/MnO2 composite for the protection of carbon steel in alkaline chloride solution. The nanorod structure (70~80 nm in diameter) and evenly dispersed conductive PANI provide the PANI/MnO2 composite with good electrical conductivity (1.9 ± 0.03 S/cm) and Seebeck coefficient (−7.71 × 103 ± 50 μV/K) and, thereby, increase the Seebeck coefficient of cement-based materials to −2.02 × 103 ± 40 μV/K and the electrical conductivity of cement-based materials to 0.015 ± 0.0003 S/cm. Based on this, the corrosion of the carbon steel was delayed after cathodic protection, which was demonstrated by the electrochemical experiment results, such as the increased resistance of the carbon steel surface from 5.16 × 102 Ω·cm2 to 5.14 × 104 Ω·cm2, increased charge transfer resistance from 11.4 kΩ·cm2 to 1.98 × 106 kΩ·cm2, and the decreased corrosion current density from 1.67 μA/cm2 to 0.32 μA/cm2, underlining the role of anti-corrosion of the PANI/MnO2 composite in the cathodic protection system.

High-efficiency droplet triboelectric nanogenerators based on arc-surface and organic coating material for self-powered anti-corrosion

The use of triboelectrification to collect dissipated energy in the environment to realize the in-situ cathodic protection of metal materials is a new clean, economical, and environmentally friendly strategy. However, the low output current density of triboelectric nanogenerators (TENGs) based on the normal inclined surface structure (I-TENG) greatly limits their application in the field of metal material cathodic protection owing to their impressed current cathodic protection capability. Here, we designed a new droplet TENG based on an arc-shaped surface structure (A-TENG) and organic coating materials to increase the output current density by more than an order of magnitude. With this new type of A-TENG, the water droplets can move on the arc-shaped structure to increase their contact-separation speed and effective contact-separation area with the triboelectric resin surface, thereby generating more triboelectric charges. The new structure can also prevent the droplets from splashing during the collision of the interface, which leads to the reduction of the triboelectric performance. Compared with I-TENG, the short-circuit current of A-TENG increases from 0.6 μA to18 μA, with an output voltage of 80 V and a power of up to 322 μW, which can easily light 50 commercial LEDs with one water droplet. In addition to the high-efficiency collection of energy from water droplets, it can also be designed as an efficient self-powered cathodic protection device for metals against corrosion through spraying on a large area. Under the action of A-TENG, the corrosion potential of the A3 carbon steel electrode dropped significantly by 580 mV, with an obvious increase in corrosion current density because the negative friction charges from TENG transferred to the surface of the protected metals for efficient impressed current cathodic protection. This device has the advantages of simple structure, low price, large-scale realization, and great application potential in ocean energy harvesting, sensing, and the self-powered corrosion protection of various marine equipment.

Fatigue testing of corroded RC continuous beams strengthened with polarized C-FRCM plate under ICCP-SS dual-function retrofitting system

The paper presents an experimental investigation into fatigue behaviour of corroded reinforced concrete (RC) continuous beams strengthened by carbon-fabric reinforced cementitious matrix (C-FRCM) under a typical dual-function retrofitting system. The retrofitting system adopted impressed current cathodic protection (ICCP) technique, which is an electro-chemical anti-corrosion technique for anodic polarization to reduce or prevent oxidation of metal, together with structural strengthening (SS) technique, which can effectively restore or improve the bearing capacity of the structure. In the experimental programme, a total of ten RC continuous beam specimens were tested under fatigue loading. The influence of key structural parameters on the fatigue life of the RC beams was examined, including the corrosion degree of the steel bar, fatigue load level, and charge density of C-FRCM plate. The calculation theory based on the transformed-section method for the cyclic stress amplitude of steel reinforcing bar in RC beam strengthened by C-FRCM plate was determined. On this basis, the S-N (cyclic stress amplitude versus cycles to failure) curves of the corroded RC continuous beams strengthened by polarized C-FRCM under the ICCP-SS dual-function retrofitting system were obtained by fitting the relevant fatigue data for fatigue design guidance.

Interface behaviour of carbon-fabric-reinforced cementitious matrix composites with ICCP technique

This paper studies the interface bonding performance of carbon-fabric-reinforced cementitious matrix (C-FRCM) composites with the impressed current cathodic protection (ICCP) technique. Single shear tests and pull-out tests on the C-FRCM composites are launched. Three current densities of 0, 100 and 150 mA/m2 in the ICCP technique are considered. The resistance–slip relationships for all the composites are presented. It is found that the maximum resistance of the specimens in the pull-out tests decreases significantly with the increase of current density in the ICCP technique. Moreover, numerical analyses are conducted to obtain a simplified interface bonding stress–slip relationship of the specimens in the pull-out tests.

Degradation behavior of multifunctional carbon fabric-reinforced cementitious matrix composites under anodic polarization

A sustainable repair method that combines impressed current cathodic protection (ICCP) and structural strengthening (SS), called ICCP-SS, has been proposed for reinforced concrete structures suffering from steel corrosion. The key component in an ICCP-SS system is a multifunctional carbon fabric-reinforced cementitious matrix (MCFRCM) composite that simultaneously functions as a tensile reinforcement and an impressed current anode. The MCFRCM composite is investigated in terms of its electrochemical performance and interfacial performance and the degradation caused by anodic polarization in alkaline solution. The results show that a relatively stable electrochemical performance can be maintained for composites polarized at a current density up to 125 mA/m2, while an exponential increase in cell voltage can be seen at higher current densities. The charge density corresponding to the occurrence of the exponential increase in cell voltage is nearly the same for all composites polarized above 125 mA/m2. Besides, the composite shows a decreased maximum pullout force and a failure mode conversion from partial rupture to complete rupture of the carbon fabric with increasing current density. The composite is degraded by the dissolution of carbon filaments due to the anodic oxidation of hydroxyl ions from the pore solution in the matrix, which results in changes in the chemical composition and morphology of the filaments. The degradation of the composite can be further correlated with the electrochemical performance and interfacial performance.

Cathodic Protection Performance Improvement of Metallic Pipelines based on Different DC Compensation Methods

• DC voltage has been studied for the pipeline using different types of DC compensation. • An integrated system has been investigated to exploit the harmful induced voltage or external PV system for compensating the cathodic protection disturbances. • Influence of different DC compensation methods using KOH-PCs without and with the FLC on the DC voltage is studied. • A comparative analysis of the UMIV results with PVSP results in terms of saving and discharging energy per year is introduced. Nowadays, natural gas in the Middle East has been discovered in extremely many quantities, and it is considered the most vital natural resource. Sometimes, the natural gas pipeline is constructed in the desert and paralleled with the high voltage overhead transmission lines (HVOHTLs). An induced AC voltage has appeared on the pipeline due to interfering with the HVOHTLs. Mainly, hydroxide potassium polarization cell (KOH-PC) has been applied to discharge this voltage to the soil within a safety limit. But, the mitigation units have negatively impacted cathodic protection (CP). The DC voltage of the pipeline is initially compensated using externally supplied impressed current cathodic protection (IMCP) units. In many cases, the external power sources have continuity and stability issues. Therefore, this paper presents different strategies as a promising solution to be utilized in reducing the disturbance of the external power sources. The first strategy is exploiting the induced voltage via converting it as DC form by using the controlled rectifier circuit and reapplying on the pipeline as a cathodic protection voltage. The second strategy involves a photovoltaic (PV) system, which integrates into the pipeline. This paper also explores the superiorly of the fuzzy system with different compensation strategies in managing the DC voltage along the pipeline to guarantee better CP performance under any disturbance in the impressed current stations. From the comparative analysis, it is observed that the behavior of the various strategies in compensating the DC voltage deterioration is reasonable. The obtained results reveal that the robustness of the fuzzy logic controller in mitigating the induced voltage and has capable of compensating the cathodic protection disturbance.

Energy harvesting of cathodic protection currents in subsea and marine structures for wireless sensor power and communication

This paper provides the first report of a means to harvest energy from stray cathodic protection currents in marine structures and thereby continuously power wireless sensors. This method is distinct from previously reported methods which utilise a conventional anode–cathode arrangement in open seawater to create a voltage cell. The underlying theory, modelling, and experimental results are described for implementation on a real application, namely annulus monitoring in a subsea production well. A broad range of new applications is envisaged, including self-powered and lifetime monitoring of safety critical parameters on marine structures, including wind turbines.

Fatigue life of C-FRCM strengthened corroded RC continuous beams under multi-intervention system

A new fatigue life prediction model for reinforced concrete (RC) beams is proposed. The model was applied to carbon-fabric reinforced cementitious matrix (C-FRCM) strengthened corroded RC beams under the impressed current cathodic protection (ICCP) and structural strengthening (SS) multi-intervention system. The stress development of steel bar in the fatigue process was captured by employing the fracture mechanics and finite element (FE) analysis. The concept of equivalent initial flaw size (EIFS) was also introduced to account for the actual initial micro crack size of steel bar. The feasibility of the model was validated through comparisons of the numerical deflection, the strain of steel bar and fatigue life of RC beams against the test results. The validated model was then used to examine the effects of key parameters including load level, corrosion degree of steel bar and polarization degree of C-FRCM. Furthermore, the results of the parametric study were used to fit S-N curve and analyse the reliability. The high accuracy of the model was shown to be suitable for the fatigue life prediction of ICCP-SS system in long-term service. It was also found that the fatigue life of the corroded RC beams was greatly improved through strengthening with C-FRCM.

SIMULATION AND SELECTION OF A PROTECTION TYPES IN THE DESIGN STAGE OF SHIPS AND OFFSHORE STRUCTURES

The requirements of the rules and regulations of the Classification Societies are based on the assumption that during the construction and operation of ships the hull corrosion protection measures are implemented according to the standards and other regulatory documents currently in force. For the purposes of designing the ship hull structures, the load components for different corrosion protection types have been obtained in the paper. There have been collected the data on the relationship between the corrosion protection weight load and the ship displacement, which enables to select the lowest corrosion protection type by weight. Technical and economic parameters of corrosion protection of ship hull structures have been analyzed. To achieve the objective of the paper a cumulative simplified approach of economic feasibility of selecting the corrosion protection type for ship hull structures has been employed. It has been determined that a total cost of protection from stress-corrosion fractures decreases for the ships with a displacement of more than 6000 [t] in the case of usage of the impressed current cathodic protection instead of the sacrificial anode cathodic one. The results of the investigation can be used by shipbuilders at the ship design stage, which enables to make a correct selection of a corrosion protection type and decreases its total cost.

Revamping corrosion damaged reinforced concrete balconies: Life cycle assessment and life cycle cost of life-extending repair methods

Facing the aging building stock, challenging times can be expected with a sharp increase of reinforced concrete buildings requiring maintenance, repair and/or replacement which induces an increase in construction and demolition waste and the use of new materials. To improve the sustainability of the renovation practice of existing concrete structures, a supporting analysis of the life cycle environmental and financial consequences has a high added value with regards to the selection of durable service life-extending repair strategy. As corrosion is the main contributor to the degradation of existing concrete structures, a residential building in a Belgian coastal environment with damaged reinforced concrete balconies is selected as case study in order to evaluate five different frequently used repair techniques by means of a life cycle assessment (LCA) and life cycle cost analysis (LCC): (i) patch repair, (ii) conventional repair, (iii) galvanic cathodic protection, (iv) impressed current cathodic protection and (v) total replacement of the element. For a short service lifetime extension (5y) of the balconies, a patch repair was revealed as the most preferable option as the existing situation is restored with a minimum of intervention. When a service life extension up to 40 years is requested, different options (conventional repair, cathodic protection) are found as competing performance options for both LCA and LCC. The total renewal of the balconies after demolition involves overall the highest LCA and LCC impact.

Current Density Limit of DC Grounding Facilities Considering Impact on Zebrafish (Brachydanio rerio)

Grounding facilities, including high-voltage DC grounding electrodes and auxiliary anodes in impressed current cathodic protection systems, inject current into the ground. This study developed an experimental platform to determine the safe limit of current density for such facilities through an analysis of fish behavior on the platform. Zebrafish (Brachydanio rerio) were selected for the experiment and placed in a tank; two rod electrodes were used to inject direct current into the water. A wireless camera was focused on the water tank to video record possible changes in fish behavior. The output voltage of the DC power source was varied, and the trajectories of the fish under various direct current fields were recorded. A tracking program was developed to analyze the trajectories and quantify the behavior of the fish. A new method combining the trajectories of fish samples with the results of current density calculations for analysis was proposed. Results demonstrated that the zebrafish could sense current in the water and turn when exposed to certain current densities. The intensity of the current at the turning points was statistically analyzed, and the threshold of current density at which the fish could no longer tolerate the current and turned was 0.4231 A/m2.

The Effect of Lightweight Functional Aggregates on the Mitigation of Anode Degradation of Impressed Current Cathodic Protection for Reinforced Concrete.

The local acidification of secondary anode mortar was regarded as the primary reason for the degradation of the anode system, leading to a decreased service life and uneven distribution of the protection current within the impressed current cathodic protection system for reinforced concrete structures. In related previous studies, a novel type of lightweight functional aggregate was designed and prepared for the secondary anode mortar system, aiming to improve anode performance via acidification mitigation. However, the relationship between optimization effects and this functional component has not been fully clarified. In this study, two sets of experiments were carried out to investigate the effects of lightweight functional aggregates on acidification mitigation and the protection of current distribution. Research results proved that the presence of this functional aggregate was beneficial for mitigated acidification propagation and a more uniform distributed protection current, which demonstrated the importance and effectiveness of acidification inhibition on the optimization of anode performance.

Analysis Of Laying And The Need For Cathodic Protection On Single Point Mooring Type Catenary Anchor Leg Mooring Buoy 035 Owned By PT. Pertamina Fuel Terminal Tuban

Corrosion is one of the most common causes of damage to mooring buoys due to oxidation on the surface of the steel plate. The purpose of this study was to determine the need and placement of cathodic protection as well as the costs required in procuring cathodic protection on moorings buoy using the rules of BKI (Indonesian Classification Bureau) and DNV (Det Norske Veritas Industry Norway). In the cathodic protection system there are two methods of cathodic protection, namely Sacrificial Anode Cathodic Protection (Sacrificial Anode) and Impressed Current Cathodic Protection (ICCP). In this study, the sacrificial anode method was used because the installation is simpler so it does not require special skills and the anode connector is cathodic protected. Mooring buoy with a height of m, a diameter of meters with a cathodic protection design life of 5 years. The anode used in this study is an anode with a Longated flush-mounted Z9.0H1 (Welded Type) with dimensions of 355 x 85 x 45 mm. From the results of this study, it was found that the total anode mass needed to protect the mooring buoy is 26.95 kg with the installation distance between the anodes on the topside hull plate is 34.557 m and the bottom swim hull plate is 47.123 m and the estimated cost required to provide mooring buoy is IDR 4,284,900.

Analysis Of Laying And The Need For Cathodic Protection On Single Point Mooring Type Catenary Anchor Leg Mooring Buoy 035 Owned By PT. Pertamina Fuel Terminal Tuban

Corrosion is one of the most common causes of damage to mooring buoys due to oxidation on the surface of the steel plate. The purpose of this study was to determine the need and placement of cathodic protection as well as the costs required in procuring cathodic protection on moorings buoy using the rules of BKI (Indonesian Classification Bureau) and DNV (Det Norske Veritas Industry Norway). In the cathodic protection system there are two methods of cathodic protection, namely Sacrificial Anode Cathodic Protection (Sacrificial Anode) and Impressed Current Cathodic Protection (ICCP). In this study, the sacrificial anode method was used because the installation is simpler so it does not require special skills and the anode connector is cathodic protected. Mooring buoy with a height of m, a diameter of meters with a cathodic protection design life of 5 years. The anode used in this study is an anode with a Longated flush-mounted Z9.0H1 (Welded Type) with dimensions of 355 x 85 x 45 mm. From the results of this study, it was found that the total anode mass needed to protect the mooring buoy is 26.95 kg with the installation distance between the anodes on the topside hull plate is 34.557 m and the bottom swim hull plate is 47.123 m and the estimated cost required to provide mooring buoy is IDR 4,284,900.

Corrosion evaluation of prestressed high‐strength steel wires with impressed current cathodic protection based on acoustic emission technique

Corrosion evaluation of prestressed high‐strength steel wires with impressed current cathodic protection based on acoustic emission technique

Data analysis of the long-term residual effect of cathodic protection on reinforced concrete structures

The application of impressed current cathodic protection (CP) is a well-established technology for the corrosion protection of reinforced concrete structures situated in marine environments. While the protective benefits of cathodic protection are well known, the lasting effects following the discontinuation of CP current are not entirely understood. This paper presents research findings on the residual protective effect which is known to occur following long durations of impressed current cathodic protection. The residual effect was replicated in university laboratories using reinforced concrete test blocks and accelerated CP testing methods. The experimental results depicted a clear improvement in the electrochemical state of the reinforcing steel with a shift of 150 to 300 mV to more positive values following CP application. The research also involved analysis of monitoring data from six in-service cathodic protection systems which were operating in Australia for nearly two decades. The behaviour of the steel potential readings was analysed and the results of the combined research confirmed that the protection provided by cathodic protection systems does not actually cease when the CP current is switched off. Rather, the embedded steel undergoes a significant and sustained shift to more positive values and this phenomenon is documented and discussed in this paper.

A review of developments in cathodic protection systems for reinforced concrete structures

Cathodic protection is a corrosion management strategy for deteriorating reinforced concrete structures or it can be used as preventative measure in situations where corrosion may be expected during the service life as a result of the environmental exposure conditions. The technology has advanced over time. There are now a number of different systems that can conveniently be considered in three categories, including impressed current cathodic protection (ICCP), hybrid cathodic protection (HCP), and galvanic cathodic protection (GCP). Asset owners need to choose which option to use possibly without understanding the different sustainability, environmental, health and safety, construction, technical, operational, and monitoring aspects. Generally, it is agreed among corrosion engineers that ICCP is the most powerful and robust solution for corrosion management in structures with widespread deterioration. HCP and GCP can also be viable options, even in the most aggressive environments with future maintenance intervention. The advantages and disadvantages of each system are discussed in detail. This paper also explains why the commonly accepted life expectancy of ICCP systems is 50 to 75 years compared to HCP and GCP, which are typically limited to 15-30 years. The details of the likely maintenance requirements, associated timescales, and whole-life costs for a 100-year design life are analysed with references to sustainability. That includes a discussion about the corrosion management system that presents the lowest embodied carbon option for different environments.