Application of galvanic cathodic protection using Zink Sheet Anodes according to ΕΝ 12696
Axios Bridge – Section Athens to Thessaloniki
Basic knowledge on cathodic protection is provided
Corrosive microenvironments at lead solder surfaces arising from galvanic cor...dondeyas
1) When stagnant water contacts copper pipe and lead solder, a corrosion cell is formed that can accelerate the corrosion of lead if the galvanic current exceeds 2 μA/cm2.
2) High galvanic currents from waters with relatively high chloride levels can prevent the passivation of solder surfaces and contribute to lead contamination.
3) If the chloride concentration increases relative to sulfate in the water, galvanic currents and associated lead contamination are greatly reduced as solder surfaces become readily passivated.
1) Nickel-copper-phosphorus layers were electrolessly deposited on anodized aluminum and aluminum alloys to improve their surface characteristics.
2) Polarization and impedance tests showed the Ni-Cu-P coating improved corrosion resistance for anodized Al7075 but decreased corrosion resistance for anodized Al2014.
3) Scanning electron microscopy images indicated the anodized aluminum surfaces were uniform, while the alloy surfaces were more defective, influencing how well the Ni-Cu-P layer adhered.
This chapter discusses how materials interact with their environments and the various corrosion mechanisms that can occur. It describes five main types of corrosion: uniform corrosion, galvanic corrosion, pitting and crevice corrosion, hydrogen embrittlement, and stress-assisted corrosion. It also discusses methods to prevent corrosion, including material selection, design modifications, cathodic protection, and use of protective coatings. Corrosion represents a huge economic cost, so preventing its deleterious effects on materials is important for engineering applications.
Depositacion electroforetica dentro de campos electricos moduladosMario ML
This document reviews electrophoretic deposition (EPD) under modulated electric fields such as pulsed direct current (PDC) and alternating current (AC). Classical EPD uses continuous direct current which can lead to issues depositing from aqueous suspensions due to water electrolysis. Modulated electric fields can reduce electrolysis and produce more uniform coatings. PDC and AC offer advantages over continuous DC like reducing bubble formation and particle aggregation. While deposition rates may decrease under modulated fields, they allow for depositing biochemical and biological materials in more active states. The document discusses EPD mechanisms and modulated field types, and their applications including in biotechnology.
A new technique to measure oxygen reduction kinetics underneath coatings using hydrogen permeation from the back side. Huge step towards characterising buried interface reactivity.
This document discusses corrosion in drinking water distribution systems and methods for corrosion control. It describes how corrosion occurs via electrochemical reactions between pipe material and water constituents. Common corrosion control strategies include pH adjustment and adding compounds like carbonates and phosphates to form a protective scale layer. Effective corrosion control requires maintaining water quality during distribution and high organic removal during treatment. The objective of this project is to study calcium carbonate behavior in distribution systems and how to alter water parameters to form a protective calcium carbonate film on pipes through computer modeling and simulation.
Basic equations related to the selection of protective paints according to el...Chris Rodopoulos
Paint systems or coatings are considered as the ultimate protection system against concrete carbonation and
against the subsequent probability of reinforcement corrosion. In this article the author is trying to explain the
use of protective paint systems and the equations describing the resulted degree of protection, making reference
to fundamental parameters controlling the carbonation process and speed. The article is written in such way as
to assist engineers involved with the protection of concrete structures either during the design or rehabilitation
phase. Examples referring to the particular environment of Greece are also included to enhance assistance to
the reader.
'Corrosion' may seem to be a simple word. But the underlying mechanism and its significance in Major industries are just reviewed in the presentation named "FAC- Flow Accelerated Corrosion"
Corrosive microenvironments at lead solder surfaces arising from galvanic cor...dondeyas
1) When stagnant water contacts copper pipe and lead solder, a corrosion cell is formed that can accelerate the corrosion of lead if the galvanic current exceeds 2 μA/cm2.
2) High galvanic currents from waters with relatively high chloride levels can prevent the passivation of solder surfaces and contribute to lead contamination.
3) If the chloride concentration increases relative to sulfate in the water, galvanic currents and associated lead contamination are greatly reduced as solder surfaces become readily passivated.
1) Nickel-copper-phosphorus layers were electrolessly deposited on anodized aluminum and aluminum alloys to improve their surface characteristics.
2) Polarization and impedance tests showed the Ni-Cu-P coating improved corrosion resistance for anodized Al7075 but decreased corrosion resistance for anodized Al2014.
3) Scanning electron microscopy images indicated the anodized aluminum surfaces were uniform, while the alloy surfaces were more defective, influencing how well the Ni-Cu-P layer adhered.
This chapter discusses how materials interact with their environments and the various corrosion mechanisms that can occur. It describes five main types of corrosion: uniform corrosion, galvanic corrosion, pitting and crevice corrosion, hydrogen embrittlement, and stress-assisted corrosion. It also discusses methods to prevent corrosion, including material selection, design modifications, cathodic protection, and use of protective coatings. Corrosion represents a huge economic cost, so preventing its deleterious effects on materials is important for engineering applications.
Depositacion electroforetica dentro de campos electricos moduladosMario ML
This document reviews electrophoretic deposition (EPD) under modulated electric fields such as pulsed direct current (PDC) and alternating current (AC). Classical EPD uses continuous direct current which can lead to issues depositing from aqueous suspensions due to water electrolysis. Modulated electric fields can reduce electrolysis and produce more uniform coatings. PDC and AC offer advantages over continuous DC like reducing bubble formation and particle aggregation. While deposition rates may decrease under modulated fields, they allow for depositing biochemical and biological materials in more active states. The document discusses EPD mechanisms and modulated field types, and their applications including in biotechnology.
A new technique to measure oxygen reduction kinetics underneath coatings using hydrogen permeation from the back side. Huge step towards characterising buried interface reactivity.
This document discusses corrosion in drinking water distribution systems and methods for corrosion control. It describes how corrosion occurs via electrochemical reactions between pipe material and water constituents. Common corrosion control strategies include pH adjustment and adding compounds like carbonates and phosphates to form a protective scale layer. Effective corrosion control requires maintaining water quality during distribution and high organic removal during treatment. The objective of this project is to study calcium carbonate behavior in distribution systems and how to alter water parameters to form a protective calcium carbonate film on pipes through computer modeling and simulation.
Basic equations related to the selection of protective paints according to el...Chris Rodopoulos
Paint systems or coatings are considered as the ultimate protection system against concrete carbonation and
against the subsequent probability of reinforcement corrosion. In this article the author is trying to explain the
use of protective paint systems and the equations describing the resulted degree of protection, making reference
to fundamental parameters controlling the carbonation process and speed. The article is written in such way as
to assist engineers involved with the protection of concrete structures either during the design or rehabilitation
phase. Examples referring to the particular environment of Greece are also included to enhance assistance to
the reader.
'Corrosion' may seem to be a simple word. But the underlying mechanism and its significance in Major industries are just reviewed in the presentation named "FAC- Flow Accelerated Corrosion"
Lithium-Seawater Battery for Undersea Sensors and Vehicleschrisrobschu
Abstract: A lithium-seawater battery is being developed for
undersea sensors and vehicles. This new energy source promises
significantly higher energy density than Commercial Off the Shelf
(COTS) primary batteries for air independent, undersea
operations. The critical enabler for this effort is a water and gas
impermeable, glass-ceramic electrolyte (GCE). The electrolyte
provides an ionic pathway between lithium and seawater and it
prevents direct contact between them. As a result, anodes made
with GCEs have shown high voltage and high efficiency in
aqueous electrolytes. The lithium metal anode is encased in a
collapsible pouch composed of a flexible laminate and a thin (250
μm) glass-ceramic electrolyte “window”. The aluminum foil
based laminate is impermeable to water and atmospheric gases.
A metal tab protrudes from the pouch as an electrical lead and a
non aqueous Li-ion electrolyte fills the gap between Li and the
ceramic membrane. Critical elements for high efficiency and high
voltage are low pouch permeability (keeping water and
atmospheric gases out and nonaqueous electrolyte in), the shape
of the pouch with respect to collapse and pressure tolerance, and
the electrochemical performance of the GCE pouch anodes in
seawater.
Keywords: Lithium Primary Battery; Seawater Battery;
Li Ion Conducting Ceramic;
2 1 power-sources_lisfc
Corrosion is an electrochemical process that causes the degradation of metal materials due to their interaction with the environment. It is a complex process influenced by physical, chemical, metallurgical, electrochemical, and thermodynamic factors. Cathodic protection is a technique used to reduce corrosion of metal surfaces by making them the cathode of an electrochemical cell. It involves connecting the metal structure to be protected to an external source of electrons (anode) to prevent corrosion at the anode site. Common methods of cathodic protection include impressed current cathodic protection using external power sources and sacrificial anode cathodic protection using reactive metals like zinc and magnesium as anodes.
Presentation Power Sources Lithium Seawater Battery (LiSWB)chrisrobschu
A lithium-seawater battery is being developed for
undersea sensors and vehicles. This new energy source promises
significantly higher energy density than Commercial Off the Shelf
(COTS) primary batteries for air independent, undersea
operations. The critical enabler for this effort is a water and gas
impermeable, glass-ceramic electrolyte (GCE). The electrolyte
provides an ionic pathway between lithium and seawater and it
prevents direct contact between them. As a result, anodes made
with GCEs have shown high voltage and high efficiency in
aqueous electrolytes. The lithium metal anode is encased in a
collapsible pouch composed of a flexible laminate and a thin (250
μm) glass-ceramic electrolyte “window”. The aluminum foil
based laminate is impermeable to water and atmospheric gases.
A metal tab protrudes from the pouch as an electrical lead and a
non aqueous Li-ion electrolyte fills the gap between Li and the
ceramic membrane. Critical elements for high efficiency and high
voltage are low pouch permeability (keeping water and
atmospheric gases out and nonaqueous electrolyte in), the shape
of the pouch with respect to collapse and pressure tolerance, and
the electrochemical performance of the GCE pouch anodes in seawater.
Power sources spring2010-presentation schumacher
The document discusses prognostic and deterministic analysis of thinning rates due to flow accelerated corrosion. It outlines developing a mechanistic model to predict thinning rates in nuclear power plant pipelines. The model considers factors like flow velocity, temperature, pH and water chemistry. Mathematical equations are presented for calculating the mass transfer coefficient and solubility driving force. CFD simulations are performed and results are validated against experimental data. Finally, the model is used to determine a 5.5 year time interval for maintenance scheduling to prevent pipe wall thickness from falling below the failure threshold.
Heavy Metals Assessment in Water Reservoirs Reinforced By Służewiecki Stream IJERA Editor
The study concerned copper and cadmium contamination in bottom sediments of selected surface water reservoirs at the urban area. The concentrations of the metals in sediments was up to 20-times higher compared with a geochemical background. Based on ecotoxicological evaluations, the toxic impact of cadmium in tested sediments can occur frequently, while for copper – it can sometimes be observed. The sediments can be classified as heavily polluted and dangerous to water biota, especially for sediment-dwelling organisms. The accumulation of metals migrating with the Służewiecki stream in reinforced reservoirs can result in their anthropopressure- related degradation.
This study examines how various physio-chemical factors affect the dissolution rate of zinc sacrificial anodes on boats in the Hamble estuary in the UK. A survey found that anodes dissolve faster in the Hamble than other UK estuaries, possibly due to lower salinity levels and stray electrical currents. Water sampling revealed zinc levels exceeding UK standards, suggesting anode dissolution contributes to this. Modelling estimated the annual zinc load from anodes as 4633 kg, with levels varying between marinas depending on factors like salinity and boat numbers. While anodes contribute to estuary zinc levels, the background level is also a significant source.
This document discusses electrochemical chloride extraction (ECE), a process for removing chloride ions from contaminated concrete and repassivating steel reinforcement. ECE works by applying an external anode and electrolyte to the concrete surface and passing a direct current between the anode and steel reinforcement cathode. This drives chloride ions out of the concrete and increases alkalinity around the steel to repassivate it. The document covers the ECE process, advantages like long-term protection with few standards, and disadvantages such as potential side effects from high current densities. It also summarizes several experimental studies on factors affecting chloride extraction effectiveness.
The document summarizes research on using electrodialysis (ED) to effectively and cost efficiently treat coal bed methane (CBM) produced water for beneficial uses like irrigation. Laboratory tests showed ED using selective cation exchange membranes removed over 90% of dissolved solids from CBM water with modest energy input. Long term tests found non-selective membranes stable with sodium bicarbonate concentrate solutions, demonstrating potential for ED to treat CBM water at large scale.
Group F has been asked by Separation Technology Sdn. Bhd to study electrodialysis, including its applications in industry and how to evaluate process performance. The document then provides an overview of electrodialysis, including its components and mechanisms. It gives an example calculation for using Faraday's law to determine membrane area and electrical requirements for an electrodialysis desalination process. Finally, it discusses some common industrial applications of electrodialysis such as desalination, waste water treatment, and wine stabilization.
Parte 2_Corrosão em concreto armado: técnicas de avaliação, monitoramento, prevenção e reabilitação. Adriana Araújo, Instituto de Pesquisas Tecnológicas do Estado de São Paulo (Instituto de Pesquisas Tecnológicas do Estado de São Paulo).
Electrical characterization of semiconductor-insulator interfaces in VLSI:ULS...Dang Trang
The document summarizes an electrical engineering student's research project characterizing semiconductor-insulator interfaces in VLSI/ULSI technology. The student fabricated metal-oxide-silicon capacitors using hafnium oxide and silicon dioxide gate dielectrics. Through capacitance-voltage measurements, the student extracted the dielectric constants of the materials and found the hafnium oxide k-value matched reported values between 18-25. Interface charges in the hafnium oxide caused shifts in the flat-band voltage. Overall, using high-k hafnium oxide allowed thicker dielectric layers while maintaining capacitance, reducing leakage currents.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document discusses cathodic and anodic protection techniques to prevent corrosion of metal structures. It describes two methods of cathodic protection: 1) sacrificial anodic protection which uses more reactive "sacrificial anodes" connected to the structure, and 2) impressed current cathodic protection which uses an external current source and inert anode. Applications include protecting underground pipelines, cables, ship hulls, tanks, and more. The document also covers anodic protection which makes the metal structure the anode and controls its potential to reduce corrosion, using a technique called potentiostat.
Yutong Liu - Final Report - Anodized Aluminium Oxide (AAO)Yutong Liu
This document summarizes research on forming iron oxide nanoparticles within the nano-pore structures of anodized aluminum oxide (AAO). It first discusses the process of creating the AAO film through a two-step anodization process and its hexagonal pore structure. It then reviews previous work demonstrating the intrinsic peroxidase activity of iron oxide nanoparticles. The research aims to investigate iron oxide nanoparticle formation kinetics within the AAO pores using electrochemical impedance spectroscopy (EIS) and equivalent circuit modeling. The document outlines the experimental design which involves fabricating AAO samples with varying iron hydroxide and iron oxide nanoparticle formation times, and then analyzing them using EIS to model the equivalent circuit and calculate parameter values.
Cathodic protection of reinforced concrete structuresRavi Kumar
Cathodic protection is used to prevent corrosion of reinforcing steel in concrete structures. There are two main cathodic protection methods: sacrificial anodes and impressed current. Sacrificial anodes made of metals like zinc or aluminum corrode instead of the steel. Impressed current uses an external DC power source connected to anodes to supply current and protect larger structures. Both methods make the steel cathode and prevent corrosion by driving electrochemical reactions. Cathodic protection is widely used to extend the life of reinforced concrete infrastructure.
Corrosion Inhibition of Carbon Steel In Sulfuric Acid by Sodium CaprylateIJERA Editor
The interaction of a sodium salt of octanoic acid, sodium caprylate (SC), with a carbon steel (CS) surface was
investigated, using range of experimental techniques. It was shown that SC acts as a good CS general corrosion
inhibitor, yielding a maximum corrosion inhibition efficiency of 77%. This high inhibition efficiency is
maintained even at higher temperatures. It was determined that SC inhibits both partial corrosion reactions, and
can thus be considered to be a mixed-type inhibitor. The adsorption of SC on the CS surface was described by
the Langmuir adsorption isotherm. It was found that this process is spontaneous, irreversible and driven by the
entropy gain. The CS surface morphology was studied by SEM and it was demonstrated that SC is a very
effective general corrosion inhibitor of CS. This also was confirmed by contact angle measurements which
showed that the CS surface became more hydrophobic when the SC was added to the solution.
The document discusses the history and evolution of electrodeionization (EDI) technology. EDI was originally developed in the 1950s to overcome concentration polarization limitations of traditional electrodialysis by filling the spaces between ion-selective membranes with ion exchange resins. This allowed EDI to effectively treat more dilute solutions. Since its commercial introduction over 16 years ago, EDI technology has matured through improvements in manufacturing techniques and membrane materials, driving increased acceptance and lower costs. EDI is now available from multiple suppliers and used in various industries beyond its original use in pharmaceutical water treatment.
The document summarizes research on the electrochemical deposition of lead dioxide nanostructured thin films. Key findings include:
- Lead dioxide nanostructures were successfully deposited on gold-coated substrates by anodic electrochemical deposition using nitric acid and lead chloride as reactants. The morphology was influenced by deposition parameters like potential, temperature, and pH.
- Deposition at higher temperatures (60°C vs room temperature) resulted in faster growth rates and denser nanostructures, as seen by SEM images.
- Both anodic and cathodic deposition were studied. Cathodic deposition allowed formation of different lead oxide phases depending on conditions, while anodic deposition selectively formed PbO2.
- The work provides a
The document discusses using capacitive deionization (CDI) to treat brackish water in remote northern locations. A test was conducted comparing CDI performance on simple NaCl solutions versus more complex water from Eagle Plains, Canada. The Eagle Plains water had lower ion removal efficiency due to its higher sulfate concentration. Further research is needed to better understand ion removal preferences and how water chemistry affects CDI performance. CDI shows promise as a low-cost, low-maintenance option for northern brackish water treatment.
This document summarizes a study that characterized graphite anodes from lithium-ion battery cells after fast charging. Multi-scale characterization techniques revealed increased disorder near the edges of graphite particles in anodes that experienced lithium plating during fast charging. Specifically, transmission electron microscopy showed wavy graphite fringes and higher d-spacings near particle edges, indicating greater lattice disorder extending 20 nm into the bulk. This disorder hinders lithium ion intercalation and favors lithium plating during repeated fast charging. Scanning electron microscopy also showed fast-charged anodes were thicker due to accumulated electrolyte reduction products in pores.
This document discusses cathodic protection, which involves applying a small electric current to the surface of a metal structure to prevent corrosion. It describes two main methods: impressed current uses an external power source connected between the structure and an auxiliary anode buried in the ground, while sacrificial anodes rely on galvanic action between the structure and more reactive anodes. The principles of cathodic protection involve driving the structure's potential negative of its corrosion potential to inhibit the corrosion reaction while increasing the cathodic reaction. Proper design considers factors like protection potentials, current density, coatings, and avoiding over-protection.
Cathodic protection prevents corrosion of steel and iron structures by making them the cathode in an electrochemical reaction. On Das Island, an impressed current cathodic protection system was installed to protect process and storage areas. This system uses 33 transformer/rectifier units with inert anode rods to introduce protective currents. When working on structures under cathodic protection, sparks can occur if the current path is interrupted, so permitting and bonding procedures must be followed to eliminate hazards, especially in hazardous areas where sparks could cause fires or explosions.
Lithium-Seawater Battery for Undersea Sensors and Vehicleschrisrobschu
Abstract: A lithium-seawater battery is being developed for
undersea sensors and vehicles. This new energy source promises
significantly higher energy density than Commercial Off the Shelf
(COTS) primary batteries for air independent, undersea
operations. The critical enabler for this effort is a water and gas
impermeable, glass-ceramic electrolyte (GCE). The electrolyte
provides an ionic pathway between lithium and seawater and it
prevents direct contact between them. As a result, anodes made
with GCEs have shown high voltage and high efficiency in
aqueous electrolytes. The lithium metal anode is encased in a
collapsible pouch composed of a flexible laminate and a thin (250
μm) glass-ceramic electrolyte “window”. The aluminum foil
based laminate is impermeable to water and atmospheric gases.
A metal tab protrudes from the pouch as an electrical lead and a
non aqueous Li-ion electrolyte fills the gap between Li and the
ceramic membrane. Critical elements for high efficiency and high
voltage are low pouch permeability (keeping water and
atmospheric gases out and nonaqueous electrolyte in), the shape
of the pouch with respect to collapse and pressure tolerance, and
the electrochemical performance of the GCE pouch anodes in
seawater.
Keywords: Lithium Primary Battery; Seawater Battery;
Li Ion Conducting Ceramic;
2 1 power-sources_lisfc
Corrosion is an electrochemical process that causes the degradation of metal materials due to their interaction with the environment. It is a complex process influenced by physical, chemical, metallurgical, electrochemical, and thermodynamic factors. Cathodic protection is a technique used to reduce corrosion of metal surfaces by making them the cathode of an electrochemical cell. It involves connecting the metal structure to be protected to an external source of electrons (anode) to prevent corrosion at the anode site. Common methods of cathodic protection include impressed current cathodic protection using external power sources and sacrificial anode cathodic protection using reactive metals like zinc and magnesium as anodes.
Presentation Power Sources Lithium Seawater Battery (LiSWB)chrisrobschu
A lithium-seawater battery is being developed for
undersea sensors and vehicles. This new energy source promises
significantly higher energy density than Commercial Off the Shelf
(COTS) primary batteries for air independent, undersea
operations. The critical enabler for this effort is a water and gas
impermeable, glass-ceramic electrolyte (GCE). The electrolyte
provides an ionic pathway between lithium and seawater and it
prevents direct contact between them. As a result, anodes made
with GCEs have shown high voltage and high efficiency in
aqueous electrolytes. The lithium metal anode is encased in a
collapsible pouch composed of a flexible laminate and a thin (250
μm) glass-ceramic electrolyte “window”. The aluminum foil
based laminate is impermeable to water and atmospheric gases.
A metal tab protrudes from the pouch as an electrical lead and a
non aqueous Li-ion electrolyte fills the gap between Li and the
ceramic membrane. Critical elements for high efficiency and high
voltage are low pouch permeability (keeping water and
atmospheric gases out and nonaqueous electrolyte in), the shape
of the pouch with respect to collapse and pressure tolerance, and
the electrochemical performance of the GCE pouch anodes in seawater.
Power sources spring2010-presentation schumacher
The document discusses prognostic and deterministic analysis of thinning rates due to flow accelerated corrosion. It outlines developing a mechanistic model to predict thinning rates in nuclear power plant pipelines. The model considers factors like flow velocity, temperature, pH and water chemistry. Mathematical equations are presented for calculating the mass transfer coefficient and solubility driving force. CFD simulations are performed and results are validated against experimental data. Finally, the model is used to determine a 5.5 year time interval for maintenance scheduling to prevent pipe wall thickness from falling below the failure threshold.
Heavy Metals Assessment in Water Reservoirs Reinforced By Służewiecki Stream IJERA Editor
The study concerned copper and cadmium contamination in bottom sediments of selected surface water reservoirs at the urban area. The concentrations of the metals in sediments was up to 20-times higher compared with a geochemical background. Based on ecotoxicological evaluations, the toxic impact of cadmium in tested sediments can occur frequently, while for copper – it can sometimes be observed. The sediments can be classified as heavily polluted and dangerous to water biota, especially for sediment-dwelling organisms. The accumulation of metals migrating with the Służewiecki stream in reinforced reservoirs can result in their anthropopressure- related degradation.
This study examines how various physio-chemical factors affect the dissolution rate of zinc sacrificial anodes on boats in the Hamble estuary in the UK. A survey found that anodes dissolve faster in the Hamble than other UK estuaries, possibly due to lower salinity levels and stray electrical currents. Water sampling revealed zinc levels exceeding UK standards, suggesting anode dissolution contributes to this. Modelling estimated the annual zinc load from anodes as 4633 kg, with levels varying between marinas depending on factors like salinity and boat numbers. While anodes contribute to estuary zinc levels, the background level is also a significant source.
This document discusses electrochemical chloride extraction (ECE), a process for removing chloride ions from contaminated concrete and repassivating steel reinforcement. ECE works by applying an external anode and electrolyte to the concrete surface and passing a direct current between the anode and steel reinforcement cathode. This drives chloride ions out of the concrete and increases alkalinity around the steel to repassivate it. The document covers the ECE process, advantages like long-term protection with few standards, and disadvantages such as potential side effects from high current densities. It also summarizes several experimental studies on factors affecting chloride extraction effectiveness.
The document summarizes research on using electrodialysis (ED) to effectively and cost efficiently treat coal bed methane (CBM) produced water for beneficial uses like irrigation. Laboratory tests showed ED using selective cation exchange membranes removed over 90% of dissolved solids from CBM water with modest energy input. Long term tests found non-selective membranes stable with sodium bicarbonate concentrate solutions, demonstrating potential for ED to treat CBM water at large scale.
Group F has been asked by Separation Technology Sdn. Bhd to study electrodialysis, including its applications in industry and how to evaluate process performance. The document then provides an overview of electrodialysis, including its components and mechanisms. It gives an example calculation for using Faraday's law to determine membrane area and electrical requirements for an electrodialysis desalination process. Finally, it discusses some common industrial applications of electrodialysis such as desalination, waste water treatment, and wine stabilization.
Parte 2_Corrosão em concreto armado: técnicas de avaliação, monitoramento, prevenção e reabilitação. Adriana Araújo, Instituto de Pesquisas Tecnológicas do Estado de São Paulo (Instituto de Pesquisas Tecnológicas do Estado de São Paulo).
Electrical characterization of semiconductor-insulator interfaces in VLSI:ULS...Dang Trang
The document summarizes an electrical engineering student's research project characterizing semiconductor-insulator interfaces in VLSI/ULSI technology. The student fabricated metal-oxide-silicon capacitors using hafnium oxide and silicon dioxide gate dielectrics. Through capacitance-voltage measurements, the student extracted the dielectric constants of the materials and found the hafnium oxide k-value matched reported values between 18-25. Interface charges in the hafnium oxide caused shifts in the flat-band voltage. Overall, using high-k hafnium oxide allowed thicker dielectric layers while maintaining capacitance, reducing leakage currents.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document discusses cathodic and anodic protection techniques to prevent corrosion of metal structures. It describes two methods of cathodic protection: 1) sacrificial anodic protection which uses more reactive "sacrificial anodes" connected to the structure, and 2) impressed current cathodic protection which uses an external current source and inert anode. Applications include protecting underground pipelines, cables, ship hulls, tanks, and more. The document also covers anodic protection which makes the metal structure the anode and controls its potential to reduce corrosion, using a technique called potentiostat.
Yutong Liu - Final Report - Anodized Aluminium Oxide (AAO)Yutong Liu
This document summarizes research on forming iron oxide nanoparticles within the nano-pore structures of anodized aluminum oxide (AAO). It first discusses the process of creating the AAO film through a two-step anodization process and its hexagonal pore structure. It then reviews previous work demonstrating the intrinsic peroxidase activity of iron oxide nanoparticles. The research aims to investigate iron oxide nanoparticle formation kinetics within the AAO pores using electrochemical impedance spectroscopy (EIS) and equivalent circuit modeling. The document outlines the experimental design which involves fabricating AAO samples with varying iron hydroxide and iron oxide nanoparticle formation times, and then analyzing them using EIS to model the equivalent circuit and calculate parameter values.
Cathodic protection of reinforced concrete structuresRavi Kumar
Cathodic protection is used to prevent corrosion of reinforcing steel in concrete structures. There are two main cathodic protection methods: sacrificial anodes and impressed current. Sacrificial anodes made of metals like zinc or aluminum corrode instead of the steel. Impressed current uses an external DC power source connected to anodes to supply current and protect larger structures. Both methods make the steel cathode and prevent corrosion by driving electrochemical reactions. Cathodic protection is widely used to extend the life of reinforced concrete infrastructure.
Corrosion Inhibition of Carbon Steel In Sulfuric Acid by Sodium CaprylateIJERA Editor
The interaction of a sodium salt of octanoic acid, sodium caprylate (SC), with a carbon steel (CS) surface was
investigated, using range of experimental techniques. It was shown that SC acts as a good CS general corrosion
inhibitor, yielding a maximum corrosion inhibition efficiency of 77%. This high inhibition efficiency is
maintained even at higher temperatures. It was determined that SC inhibits both partial corrosion reactions, and
can thus be considered to be a mixed-type inhibitor. The adsorption of SC on the CS surface was described by
the Langmuir adsorption isotherm. It was found that this process is spontaneous, irreversible and driven by the
entropy gain. The CS surface morphology was studied by SEM and it was demonstrated that SC is a very
effective general corrosion inhibitor of CS. This also was confirmed by contact angle measurements which
showed that the CS surface became more hydrophobic when the SC was added to the solution.
The document discusses the history and evolution of electrodeionization (EDI) technology. EDI was originally developed in the 1950s to overcome concentration polarization limitations of traditional electrodialysis by filling the spaces between ion-selective membranes with ion exchange resins. This allowed EDI to effectively treat more dilute solutions. Since its commercial introduction over 16 years ago, EDI technology has matured through improvements in manufacturing techniques and membrane materials, driving increased acceptance and lower costs. EDI is now available from multiple suppliers and used in various industries beyond its original use in pharmaceutical water treatment.
The document summarizes research on the electrochemical deposition of lead dioxide nanostructured thin films. Key findings include:
- Lead dioxide nanostructures were successfully deposited on gold-coated substrates by anodic electrochemical deposition using nitric acid and lead chloride as reactants. The morphology was influenced by deposition parameters like potential, temperature, and pH.
- Deposition at higher temperatures (60°C vs room temperature) resulted in faster growth rates and denser nanostructures, as seen by SEM images.
- Both anodic and cathodic deposition were studied. Cathodic deposition allowed formation of different lead oxide phases depending on conditions, while anodic deposition selectively formed PbO2.
- The work provides a
The document discusses using capacitive deionization (CDI) to treat brackish water in remote northern locations. A test was conducted comparing CDI performance on simple NaCl solutions versus more complex water from Eagle Plains, Canada. The Eagle Plains water had lower ion removal efficiency due to its higher sulfate concentration. Further research is needed to better understand ion removal preferences and how water chemistry affects CDI performance. CDI shows promise as a low-cost, low-maintenance option for northern brackish water treatment.
This document summarizes a study that characterized graphite anodes from lithium-ion battery cells after fast charging. Multi-scale characterization techniques revealed increased disorder near the edges of graphite particles in anodes that experienced lithium plating during fast charging. Specifically, transmission electron microscopy showed wavy graphite fringes and higher d-spacings near particle edges, indicating greater lattice disorder extending 20 nm into the bulk. This disorder hinders lithium ion intercalation and favors lithium plating during repeated fast charging. Scanning electron microscopy also showed fast-charged anodes were thicker due to accumulated electrolyte reduction products in pores.
This document discusses cathodic protection, which involves applying a small electric current to the surface of a metal structure to prevent corrosion. It describes two main methods: impressed current uses an external power source connected between the structure and an auxiliary anode buried in the ground, while sacrificial anodes rely on galvanic action between the structure and more reactive anodes. The principles of cathodic protection involve driving the structure's potential negative of its corrosion potential to inhibit the corrosion reaction while increasing the cathodic reaction. Proper design considers factors like protection potentials, current density, coatings, and avoiding over-protection.
Cathodic protection prevents corrosion of steel and iron structures by making them the cathode in an electrochemical reaction. On Das Island, an impressed current cathodic protection system was installed to protect process and storage areas. This system uses 33 transformer/rectifier units with inert anode rods to introduce protective currents. When working on structures under cathodic protection, sparks can occur if the current path is interrupted, so permitting and bonding procedures must be followed to eliminate hazards, especially in hazardous areas where sparks could cause fires or explosions.
Corrosion Assessment – Half-Cell Potential Method for reinforced concreteYash Shah
This document discusses the half-cell potential method for assessing corrosion in reinforced concrete structures. It covers the passive layer on steel reinforcement, how the half-cell potential apparatus works, factors that influence readings, and how to interpret results. A case study examines measurements on a prestressed concrete bridge near the coast and finds that while some readings were above corrosion thresholds, the overall gradient indicated low corrosion risk when considering multiple factors. Precise measurement location and accounting for temperature and moisture are important.
Corrosion and Degradation of Materials-chapter 16ssuser2fec01
Cost of Corrosion
Fundamentals of Corrosion
Electrochemical reactions
EMF and Galvanic Series
Concentration and Temperature (Nernst)
Corrosion rate
Corrosion prediction (likelihood)
Polarization
Protection Methods
Behavior of carbon steel in simulated concrete pore solutions of air-entraine...Adriana de Araujo
In Brazil, the air-entrained concrete has been extensively used as structural walls of housing units. Some of these units built recently in urban areas were inspected. Upon inspection, a significant variation of the potential corrosion measurement was obtained and reddish stains on the surface of the reinforcement were also observed, indicating active state of corrosion. Not always the concrete was fully carbonated and a chloride contamination was not detected. The occurrence of crevice corrosion was pointed as a possible cause of the premature corrosion as a non-uniform contact of the concrete with the reinforcement surface was detected.
In order to better understand the occurrence of premature corrosion of the inspected reinforcement, a complementary study was conducted at the laboratory to characterize air-entrained concretes and evaluate the behavior of steel bars immersed in solutions that simulate the water in the pores of these concrete and compare them to the pore solution of an ordinary Portland concrete.
The steel bars were evaluated under three conditions: blasted, corroded and galvanized. An intentional crevice was introduced on one of the bars. The behavior of the bars was monitored by visual examination and by electrochemical measurements. Finally, the corrosion rate was calculated. Tests on concrete specimens were also conducted to validate the results.
The characterization tests showed an inferior quality of the air-entrained concretes, having both high concentrations of pores, many of them fully interconnected. This justified the high deep carbonation observed in a short period of time and a variable electrical resistivity detected in the field.
The pore-solution immersion tests showed the higher corrosion susceptibility of metallic reinforcement in air-entrained concretes especially at the crevice areas. In the studied air-entrained concretes, the corrosion occurred preferentially under the sealant applied on the bar extremities. In one of them, corrosion was also observed on the free surface of the blasted bars. The corrosion was also observed in the air-entrained concrete specimens, confirming the tests solution results.
Characterization of corrosion of x70 pipeline steel in thin electrolyte layerA X.S
This document describes a study that used scanning Kelvin probe technique to characterize the corrosion behavior of X70 pipeline steel in thin layers of near-neutral and high pH solutions. The key findings are:
1) In a thin near-neutral pH solution layer (60 μm), passivity could develop on the steel surface due to iron ions reaching saturation, allowing iron carbonate precipitation. Thicker layers inhibited passivation.
2) In thin high pH solution layers, the steel maintained passivity and cathodic reactions were limited by oxygen diffusion. Polarization behavior was independent of layer thickness.
3) Bulk solution tests showed active corrosion in near-neutral pH but passivity in high pH, without cathodic
Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...Onyedikachi Martins
This document discusses a student project to design and install a cathodic protection system on coated steel, similar to what is used on parts of a dredger. The student installed a sacrificial zinc anode alongside the steel to act as a galvanic anode and protect the steel from corrosion. The cathodic protection system was then monitored and the potential readings were within the standard protected range, demonstrating that the steel was effectively protected from corrosion by this method. In summary, the student designed and tested a basic galvanic cathodic protection system using a zinc anode to prevent corrosion of coated steel.
This research aims to determine the chloride ion permeability in alkali-activated binder systems like fly ash, as a more sustainable alternative to ordinary Portland cement. The experimental process involved three phases: (1) characterizing chloride ion diffusion through non-steady state migration testing, (2) analyzing the pore structure through mercury intrusion porosimetry, and (3) evaluating chloride binding through electrical impedance spectroscopy. Preliminary results found that alkali-activated fly ash indicated increased impedance after migration testing, suggesting pore refinement and chloride binding occurred.
This document discusses the adsorption of carboxymethyl cellulose (CMC) onto alumina particles. CMC and alumina were chosen because their surface charges can be altered by pH, allowing the study of particle aggregation and stabilization. Electric light scattering and microelectrophoresis techniques were used to measure how CMC adsorption affects the electric polarizability and surface charge of the alumina particles over time and across a range of CMC concentrations. The results provide conditions for complete CMC adsorption and suspension stability.
This document summarizes the preparation and characterization of carbon fiber-grafted poly(glycidyl methacrylate) (CF-PGMA) functionalized with the chelating ligand cyclam (CF-PGMA-Cy) for uptake of copper ions. The fibers were prepared in four steps: (1) electrografting of an aryl diazonium salt initiator onto carbon fibers, (2) surface-initiated atom transfer radical polymerization of glycidyl methacrylate, (3) functionalization of PGMA grafts with cyclam, and (4) characterization of copper ion uptake. X-ray photoelectron spectroscopy and contact angle measurements showed successful functionalization after each step. Copper uptake
Advanced Cathodic Protection - CP Series - Eric Langelundnacetwincities
This document provides an overview of cathodic protection concepts including:
- The four elements that create a galvanic corrosion cell and the polarization process that occurs.
- How coating characteristics can affect polarization rates.
- Common methods for measuring structure-to-electrolyte potentials and criteria for determining effective cathodic protection.
- Types of reference electrodes used for measurements, including the copper-copper sulfate electrode.
The summary discusses key aspects of cathodic protection and how polarization reduces the potential difference between anodes and cathodes to stop the corrosion reaction.
1) Prestressed concrete sleepers can deteriorate over time due to delayed ettringite formation caused by changes in cement production methods. Maintaining a low alkali content in cement can help prevent this.
2) In prestressed concrete, tensioning force is transmitted through adhesion between steel reinforcement and concrete. This adhesion can be weakened by microcracks, causing issues with force transmission.
3) Improper design of the near-front zone of prestressed concrete sleepers with clustered steel reinforcement can lead to cracking and spalling due to bursting, spalling, and splitting effects from stress concentrations. Additional confinement reinforcement is needed.
1 s2.0-0040609083905771-main contact resistance and methods for its determina...Kadu Brito
This document discusses contact resistance and methods for determining it. It begins by introducing the topic and defining key terms like contact resistance (Rc) and specific contact resistance (Pc). It then summarizes three main methods for measuring contact resistance: the two-, three-, and four-terminal resistor structures. For each method, parasitic contributions must be accounted for to isolate the specific interface resistance (Pi), which is the theoretical quantity of interest. The document goes on to provide relevant theoretical background on carrier transport across metal-semiconductor interfaces and models of conduction mechanisms.
Corrosion is the process by which metals convert to lower-energy oxides. It involves the oxidation of metal atoms and the reduction of oxidants like oxygen or water. There are two half-cell reactions: the anodic reaction where metal is oxidized and electrons are released, and the cathodic reaction where these electrons are consumed. Cathodic protection prevents corrosion by making the metal surface the cathode of an electrochemical cell using sacrificial anodes or impressed current systems.
This document discusses corrosion in reinforced concrete structures, including its history and causes. It provides details on several bridge failures due to corrosion, including the collapse of the Mianus River bridge in 1983 and the Silver Bridge in 1967. The document also discusses experimental work on corrosion, including the effects of strain level, corrosion duration, and stress. It notes that carbonation and chloride ions can lead to corrosion by lowering the pH and attacking the steel. Permeability of concrete and thermal movement are identified as key causes of cracks in structures. Protection techniques like coatings and cathodic protection are also mentioned.
Paul Ahern - Copper/ low-K Interconnect TechnologyPaul Ahern
This document reviews the development of interconnect technology in integrated circuits from aluminum to copper and low-k dielectrics. It discusses how copper replaced aluminum as the interconnect material due to its higher conductivity and electromigration resistance. Copper is patterned using the damascene process where it is deposited into trenches etched into a dielectric. As feature sizes shrank below 180nm, the dielectric constant of the interlayer dielectric (ILD) needed to be reduced to prevent delays, leading to the use of low-k materials like carbon-doped oxides and porous oxides with dielectric constants as low as 2.1.
This document provides an overview and agenda for a presentation on modern cathodic protection for piping. It discusses corrosion basics, criteria for cathodic protection, design considerations for galvanic anode systems, and types of cathodic protection systems. The document uses examples to demonstrate how to design a cathodic protection system using galvanic anodes to protect an underground coated steel pipe over 20 years. It compares zinc, standard magnesium, and high-potential magnesium anodes in terms of current output, life expectancy, and cost.
This document provides an introduction and background on Complementary Metal Oxide Semiconductor (CMOS) technology. It discusses key components of a CMOS circuit including NMOS, PMOS, photolithography, etching, chemical mechanical planarization, shallow trench isolation, contacts, vias, and interlayer dielectrics. The objectives of the project are to identify defects in a defective CMOS sample using electrical testing, scanning laser optical microscopy, passive voltage contrast under SEM, and focused ion beam with EDX to determine the root cause of the defect.
Properties of Fluids, Fluid Statics, Pressure MeasurementIndrajeet sahu
Properties of Fluids: Density, viscosity, surface tension, compressibility, and specific gravity define fluid behavior.
Fluid Statics: Studies pressure, hydrostatic pressure, buoyancy, and fluid forces on surfaces.
Pressure at a Point: In a static fluid, the pressure at any point is the same in all directions. This is known as Pascal's principle. The pressure increases with depth due to the weight of the fluid above.
Hydrostatic Pressure: The pressure exerted by a fluid at rest due to the force of gravity. It can be calculated using the formula P=ρghP=ρgh, where PP is the pressure, ρρ is the fluid density, gg is the acceleration due to gravity, and hh is the height of the fluid column above the point in question.
Buoyancy: The upward force exerted by a fluid on a submerged or partially submerged object. This force is equal to the weight of the fluid displaced by the object, as described by Archimedes' principle. Buoyancy explains why objects float or sink in fluids.
Fluid Pressure on Surfaces: The analysis of pressure forces on surfaces submerged in fluids. This includes calculating the total force and the center of pressure, which is the point where the resultant pressure force acts.
Pressure Measurement: Manometers, barometers, pressure gauges, and differential pressure transducers measure fluid pressure.
Supermarket Management System Project Report.pdfKamal Acharya
Supermarket management is a stand-alone J2EE using Eclipse Juno program.
This project contains all the necessary required information about maintaining
the supermarket billing system.
The core idea of this project to minimize the paper work and centralize the
data. Here all the communication is taken in secure manner. That is, in this
application the information will be stored in client itself. For further security the
data base is stored in the back-end oracle and so no intruders can access it.
Open Channel Flow: fluid flow with a free surfaceIndrajeet sahu
Open Channel Flow: This topic focuses on fluid flow with a free surface, such as in rivers, canals, and drainage ditches. Key concepts include the classification of flow types (steady vs. unsteady, uniform vs. non-uniform), hydraulic radius, flow resistance, Manning's equation, critical flow conditions, and energy and momentum principles. It also covers flow measurement techniques, gradually varied flow analysis, and the design of open channels. Understanding these principles is vital for effective water resource management and engineering applications.
Particle Swarm Optimization–Long Short-Term Memory based Channel Estimation w...IJCNCJournal
Paper Title
Particle Swarm Optimization–Long Short-Term Memory based Channel Estimation with Hybrid Beam Forming Power Transfer in WSN-IoT Applications
Authors
Reginald Jude Sixtus J and Tamilarasi Muthu, Puducherry Technological University, India
Abstract
Non-Orthogonal Multiple Access (NOMA) helps to overcome various difficulties in future technology wireless communications. NOMA, when utilized with millimeter wave multiple-input multiple-output (MIMO) systems, channel estimation becomes extremely difficult. For reaping the benefits of the NOMA and mm-Wave combination, effective channel estimation is required. In this paper, we propose an enhanced particle swarm optimization based long short-term memory estimator network (PSOLSTMEstNet), which is a neural network model that can be employed to forecast the bandwidth required in the mm-Wave MIMO network. The prime advantage of the LSTM is that it has the capability of dynamically adapting to the functioning pattern of fluctuating channel state. The LSTM stage with adaptive coding and modulation enhances the BER.PSO algorithm is employed to optimize input weights of LSTM network. The modified algorithm splits the power by channel condition of every single user. Participants will be first sorted into distinct groups depending upon respective channel conditions, using a hybrid beamforming approach. The network characteristics are fine-estimated using PSO-LSTMEstNet after a rough approximation of channels parameters derived from the received data.
Keywords
Signal to Noise Ratio (SNR), Bit Error Rate (BER), mm-Wave, MIMO, NOMA, deep learning, optimization.
Volume URL: https://airccse.org/journal/ijc2022.html
Abstract URL:https://aircconline.com/abstract/ijcnc/v14n5/14522cnc05.html
Pdf URL: https://aircconline.com/ijcnc/V14N5/14522cnc05.pdf
#scopuspublication #scopusindexed #callforpapers #researchpapers #cfp #researchers #phdstudent #researchScholar #journalpaper #submission #journalsubmission #WBAN #requirements #tailoredtreatment #MACstrategy #enhancedefficiency #protrcal #computing #analysis #wirelessbodyareanetworks #wirelessnetworks
#adhocnetwork #VANETs #OLSRrouting #routing #MPR #nderesidualenergy #korea #cognitiveradionetworks #radionetworks #rendezvoussequence
Here's where you can reach us : ijcnc@airccse.org or ijcnc@aircconline.com
Digital Twins Computer Networking Paper Presentation.pptxaryanpankaj78
A Digital Twin in computer networking is a virtual representation of a physical network, used to simulate, analyze, and optimize network performance and reliability. It leverages real-time data to enhance network management, predict issues, and improve decision-making processes.
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...Transcat
Join us for this solutions-based webinar on the tools and techniques for commissioning and maintaining PV Systems. In this session, we'll review the process of building and maintaining a solar array, starting with installation and commissioning, then reviewing operations and maintenance of the system. This course will review insulation resistance testing, I-V curve testing, earth-bond continuity, ground resistance testing, performance tests, visual inspections, ground and arc fault testing procedures, and power quality analysis.
Fluke Solar Application Specialist Will White is presenting on this engaging topic:
Will has worked in the renewable energy industry since 2005, first as an installer for a small east coast solar integrator before adding sales, design, and project management to his skillset. In 2022, Will joined Fluke as a solar application specialist, where he supports their renewable energy testing equipment like IV-curve tracers, electrical meters, and thermal imaging cameras. Experienced in wind power, solar thermal, energy storage, and all scales of PV, Will has primarily focused on residential and small commercial systems. He is passionate about implementing high-quality, code-compliant installation techniques.
We have designed & manufacture the Lubi Valves LBF series type of Butterfly Valves for General Utility Water applications as well as for HVAC applications.
1. Axios Bridge – Section Athens to Thessaloniki
Dr. Chris A Rodopoulos, Dr. P. Panetsos and Mr. I. Koropoulis
Application of galvanic cathodic protection using Zink Sheet Anodes according to ΕΝ 12696
2. Axios bridge consists of two sections. The section Athens to Thessaloniki was given to traffic in
1973. The section Thessaloniki to Athens was inaugurated in 1988. The bridge is part of E75
motorway.
Axios Bridge – Historical Data
4. The bridge is made of 29 spans of 30 m each resulting in overall length of 870m. Due to river
crossing the bridge is founded on R/C piles.
Axios Bridge – Historical Data
5. The superstructure is made of longitudinal and transverse prestressed beams.
Axios Bridge – Historical Data
8. A CuSO4 reference electrode has been used. All values in mV.
Measurements and Pathology – Half Cell Measurements of External Beam
9. Measurements and Pathology – Half Cell Measurements of External Beam
– Projection of values on beam
The high negative values at area A indicate waterproofing failure of the expansion joint. The high
corrosion propensity at areas B and C, indicate potential local failure of the deck waterproofing
layer.
Area Α
Area Β Area C
10. Measurements and Pathology – Half Cell Measurements of External Beam
– Projection of values on tendon tracks
Note that the anchors of tendons 3-8, exhibit high corrosion potential. Similar problem is
identified at the location of tendons 9, 11 and 12.
12. Measurements and Pathology – Concrete Electrical Resistivity Measurements– Projection of
values on beam
Electrical resistivity is an indirect way of evaluating concrete’s build in moisture and hence the
susceptibility to ionic current movement (controls the cathodic / oxygen reaction). To
acknowledge the importance of the measurements, it is worth noting that the electrical
resistivity of C30/37 concrete, having build in (hygroscopic) moisture of 2% w. t., is around 70
KOhm cm.
13. Measurements and Pathology– Linear Polarisation Measurements (LPR)
All values in μΑ/cm2. The measured values classified corrosion belonging into the low to
medium rate according to the above Table. Certain areas in purple are classified as passive.
14. Measurements and Pathology– Linear Polarisation Measurements (LPR) – Projection of values
on beam
It is important to consider that low values of corrosion current density are most likely to
increase with time compared to high values which are bounded by the nature of concrete’s
pathology. It is also worth noting that values above 0.5 μΑ/cm2 can lead to complete loss of
bond strength within 2-10 years.
15. Measurements and Pathology– Linear Polarisation Measurements (LPR) – Projection of values
on tendon tracks
Projection of the measured values over the design and especially over tendon tracks is perhaps
the most crucial action when evaluating corrosion in prestressed elements. The generated
image help us identify critical locations while at the same time provides information regarding
potential causes. Herein, we can easily identify that tendons No. 8, 9, 11, 12, are within the area
demonstrating the highest corrosion rate of the sample. It is important to note that the
transverse beam is also critically corroding. The surface tendon 11 appears to experience
significant corrosion rate due to overhead failure of waterproofing.
16. Measurements and Pathology – Concrete Pathology
Axios Bridge is located in a semi-urban environment experiencing high humidity due to river. The distance
from the sea is over 5 Km and therefore the potential of airborne chlorides diffusing into concrete is
considered as negligible. The bridge is rarely subjected to de-icing salts. Even though vehicular traffic is
substantial, the location experiences CO2 concentration below 300 ppm. In conjunction with the high
humidity of the area, concrete experiences a rather low carbonation rate.
The bridge is suffering from poor storm water drainage, non sealed expansion joints and damaged deck
waterproofing layer.
Accessibility is the most crucial issue in the assessment of concrete's pathology in large structures and
especially prestressed bridges. Herein, it is imperative to collect samples from locations, a) being critical to
the load bearing capacity, b) being indicative to the actual problem both in terms of chemistry and
concentration and c) providing a sound basis for damage classification. The later, is mostly governed by
sample population and the type of pathology being initially identified. The level of carbonation and chloride
attack, coming from airborne chlorides, is perhaps the easiest of all since they rarely demonstrate significant
position variations.
Tendon anchors and tendons are critical items which require particular attention. Surface tendons are
notoriously difficult to locate and approach even though is widely known of being liable to corrosion.
Similarly, tendon anchors in old bridges are usually located in tight spaces with poor access.
17. Due to accessibility issues, samples were collected from areas being close to the expansion joints and
experiencing spalling. Indicative results are shown in the Table below.
Samples Concentration of Total Chlorides
Cement (% w.t) - ASTM C1152
Concrete Alkalinity
Sample 1 0.19 8.2
Sample 2 0.25 6.9
Sample 3 0.27 7.7
Sample 4 0.21 7.8
Sample 5 0.27 7.6
According to EN 8110, a total chloride concentration of 0.1% is considered as threshold value for
critical corrosion in prestressed elements. The above limit however refers to concrete alkalinity,
pH, being >11. In the samples, concrete alkalinity has dropped as low as 7.6 indicating that
critical chloride levels are several orders below 0.1%. In addition, alkalinity values are significant
below the lower limit value indicating carbonation, i.e. pH=8.4. The phenomenon of low
alkalinity is attributed to water soluble chemicals from tyre wear, brake wear particle emission,
and exhaust discharges (traffic dust).
Measurements and Pathology – Concrete Pathology
All samples have been collected at depth equal to concrete cover thickness (30mm).
18. Traffic dust’s most common chemicals and their typical concentration
Measurements and Pathology – Concrete Pathology
Most of these chemical are known to disintegrate both concrete and steel (ACI 515.1R).
19. Measurements and Pathology – Concrete Pathology
Axios Bridge experiences the simultaneous effect of chlorides due to de-icing salts along with chemical
attack due to traffic dust. Both, in their soluble form shall be considered as the main cause of corrosion.
Herein, once again accessibility is vital in order to collect samples that can be analysed in order to provide
secure information regarding concentration of the hazardous chemicals and their reactions with cement
constituents. Indirectly we can overcome the problem by comparing our LPR measurements with the limits
of certain exposure conditions as depicted in the Table below.
Exposure Class per EN 206-1 LPR Values ( μΑ/cm2)
Average Standard Deviation
XC1 0 -
XC2 0.35 0.26
XC3 0.17 0.08
XC4 0.43 0.26
XD1 0.35 0.26
XD2 2.60 1.70
XS1 2.60 1.70
XS2 - -
XS3 6.00 3.50
Axios bridge belongs into classes XD2 and XD3 (de-icing salts). The reader can easily compared the
previously reported values and acknowledge their deviation form the above limits. Such difference indicates
the supplementary effect provide by traffic dust residues.
20. Basic Principles of Galvanic Protection
Corrosion is based on two reactions
1st Half Cell Reaction Anodic reaction – Oxidation of iron, Iron is oxidized from Fe (oxidation state
0) to Fe 2+ (oxidation state +2).
2nd Half Cell Reaction Cathodic reaction– Reduction of oxygen, the liberated electrons from the
oxidation of iron are consumed by oxygen in the presence of water to form hydroxyl (OH−).
In this reaction oxygen is electrochemically reduced from O2 (oxidation state 0) to OH− (oxidation
state −2).
21. Basic Principles of Galvanic Protection
If there is no external electric source of electrons, the anodic reaction must generate electrons
at exactly the same rate as the cathodic reaction consumes them.
If electrons were withdrawn from the metal surface, it might be anticipated that the anodic
reaction would speed up (to replace the lost electrons) and the cathodic reaction would slow
down, because of the existing shortfall of electrons. It follows that the rate of metal
consumption would increase.
If however additional electrons were introduced at the metal surface, the cathodic reaction
would speed up (to consume the electrons) and the anodic reaction would be inhibited; metal
dissolution would be slowed down.
22. Basic Principles of Galvanic Protection
Inhibiting corrosion via external source of electrons is the basic principle of cathodic protection.
In the case of electrons being provide by an electric source, cathodic protection refers to
Induced Current Cathodic Protection (ICCP). If the source of electrons is provided by a sacrificial
metal, being more electronegative, cathodic protection refers to Galvanic Cathodic Protection.
This fundamental principle can be appreciated via the Poubraix diagram for Iron.
The grey area in the diagram on the left
encapsulates the limits of cathodic
protection.
23. Basic Principles of Galvanic Protection
Schematically, the excess electrons provide by galvanic cathodic protection (leading to corrosion
inhibition) is shown below.
24. Basic Principles of Galvanic Protection
The availability and the potential of metals able to provide excess electrons is governed by the
Standard Reduction Potential Table. We can easily identify that, Zn, Al and Li are more
electronegative than Fe and therefore can provide excess electrons.
Since the excess electrons are generated by the corrosion of the more electronegative metal,
the term sacrificial metal is widely used.
25. Basic Principles of Galvanic Protection
In Galvanic Cathodic Protection, the potential difference alone is not enough as to proceed with the
selection of the anode metal. Generated anode (sacrificial metal) current density and electrochemical
capacity (Amp-h/Kg) are also important parameters .
The “Potential volts” refer also referred as polarisation potential. For steel in concrete, a polarized
potential more negative than –800 mV measured with respect to silver/silver chloride reference electrode is
required by EN 12696. The reader shall not confused potential values given by different reference
electrodes. In this case, the -1100 mV of the Cu/CuSO4 are equal to -1044 mV of Ag/AgCl 0.05M KCl.
Simplistically, electrochemical capacity is the result of Faraday's law. For example, pure zinc has a theoretical
maximum capacity of 820 Ah per kilogram. This means that if a zinc anode were to discharge one ampere
continuously, one kilogram would be consumed in 820 hours. If this kilogram was discharging one tenth of
an ampere, it would be totally consumed in 8200 hours or 48 weeks. Actually, zinc anodes operate, typically,
at about 95 % efficiency. This means that the energy content available for useful current output would be
820 x 0.95, or 779 Ah per kg.
26. Basic Principles of Galvanic Protection
Cathodic protection current density is currently defined by regulation. Even though differences can be easily
identified, the minimum requirements remain approximately fixed.
27. Basic Principles of Galvanic Protection
Variations in the range of cathodic protection current density are mostly acknowledged by the diagram
below.
Here the reader can study, different cathodic protection current density requirements as per chloride ions
concentration in concrete. SCE refers to Saturated Calomel Electrode.
28. Basic Principles of Galvanic Protection
Variations in cathodic protection current densities throughout the years have been classified in order to
provide a sound basis over which repair cost can be realistically estimated.
Current density requirements along with the surface area of steel to be protected (demand), define among
others parameters, whether ICCP or galvanic protection is to be used. It is clear that high current demand
for a large period of time consumes faster the sacrificial anode while at the same time might not be able to
generate the required potential.
The reader can easily relate the above table to that of slide no. 19 .
29. Axios Bridge Galvanic Protection
Tendon tracks, tendon anchors and non sealed joints create a rather complex scenario for uniform
polarisation potential distribution. In the case of existing bridges offering limited accessibility, the problem
exponentially increases leading to over-polarisation issues and potential hydrogen gas generation . The use
of control sensors and complex programming of the cathodic protection control unit can sometimes only
provide limited solution. In addition to the above, a cathodic protection control unit is usually unprotected
from actions of vandalism and theft.
For the above reasons, the use of Galvanic protection was chosen. Due to the large surface area and the
difficulty in boring to encase embedded anodes, the use of Zinc / Hydrogel Anode or known as Zinc layer
Adhesive Anode or ZLA. This anode consisted of a zinc foil, which measured 0.25 mm thick by 0.25 m wide ,
a conductive adhesive gel (3M Company’s Hydrogel™) bonded to one side of the foil, and a release paper
sticking to the other side of the adhesive gel. In this application, ZLA provided by Mapei under the
commercial name of Mapeshield E25 was used.
Mapeshield E25 provides 455 grams of Zinc per running
meter and is certified according to EN 12696.
30. Axios Bridge Galvanic Protection
Calculations and the subsequent plans were based on an initial protection current density of 5mΑ/m2 for
the first 12 months followed by a value of 1.5mΑ/m2 for the remaining protection period. A 10 year overall
protection period was considered. A safety factor of 1.1 was implemented. Two reference electrodes were
positioned to monitor the tendons. The overall anode performance level was set at 80%.
31. Application of Galvanic Protection - Step A - Hydro blasting 500 Bar
Rigorous cleaning of the surface is imperative for Hydrogel to maintain a uniform and maximum
ion current flow. The pressure refers to nozzle output.
32. It is important to note that the nozzle to surface distance was kept between 5-10 cm. It is a
common mistake of contractors performing hydro blasting to operate at longer distances. A
practical tip identifying correct distance (depends on concrete strength, pressure and flow rate
of the unit) is to achieve concrete skin (2-4mm) removal at a rate of > 0.1 m2/min.
Application of Galvanic Protection - Step A - Hydro blasting 500 Bar
33. Hydro-blasting at 500 bars, is usually enough to remove loose concrete due to spalling.
Application of Galvanic Protection - Step A - Hydro blasting 500 Bar
34. Prior to any patch repair it is important to check for electrical continuity. In the case where
electrical continuity (a value <0.1V at DC setting indicatives continuity) is not obtained, the
contractor shall proceed with artificial connection using the fixings and a piece of the
recommended cathodic protection cable. The photograph shows a “bridge” used to achieve
electrical continuity between two stirrups. Connections and fixings are protected using a
conductive sealant.
Application of Galvanic Protection – Step B – Local Patch Repairs
35. Fixing to steel reinforcement is made using a low voltage cable. Usually type FG7R-0.6/1KV 1 Χ
8. In this particular application connection was made using stainless steel rivets and ring eye
terminals.
Application of Galvanic Protection – Step B – Local Patch Repairs
36. Patch repair grout should be according to ΕΝ 1504 parts 2,3 while is mandatory to have an
electrical resistivity < 10 KOhm cm (ΕΝ 12696). This is because the grout should allow the
unrestricted row of ions generated by the Zinc / Hydrogel Anode.
Application of Galvanic Protection – Step B – Local Patch Repairs
37. Sufficient time shall be allowed prior to the application of the ZLA over the patched area. In such
applications, grout strength is not an indicative parameter. The contractor shall measure the
electrical resistivity using a Wenner Probe. Once the reading is within its declared value by the
manufacturer, the contractor can proceed to the next step.
Application of Galvanic Protection – Step B – Local Patch Repairs
38. After removing the releasing sheet protecting Hydrogel from air, ZLA can be applied on concrete
surface. A rubber mallet is usually used to secure one edge of the anode sheet. A rubber roller is
finally used for final placement and straightening. The stiffness of ZLA and the usually uneven
surface of concrete, usually prevent air being trapped underneath.
Application of Galvanic Protection – Step C – Placing the ZLA
39. A covermeter is used to identify the location and cover thickness of reinforcement intending to
receive connection to the anode. The action should be performed prior to the placement of ZLA
since measurement over zinc cancels the operation of the covermeter.
Application of Galvanic Protection – Step C – Placing the ZLA
40. A wedge anchor is used to connect reinforcement to ZLA. The location has been previously
identified by covermeter (reinforcement free zone) and indicated on the ZLA using a marker.
Correct connection once again requires electrical continuity measurement.
Application of Galvanic Protection – Step C – Placing the ZLA
41. The process is repeated until all ZLA sheets have been placed. Note that all required connections to
reinforcement are established. That allows the contractor to continuously check and recheck electrical
continuity. A valid order is to start the check between the first ZLA and the last reinforcement connection
and continue the process inwards, i.e. the second ZLA or reinforcement connection with the N-1
reinforcement connection (N is the total number of connections), the third ZLA or reinforcement connection
with the N-2 reinforcement connection, etc.
Connection to steel was made using the following steps,
a) Detection of location and depth of steel using covermeter,
b) Drilling of concrete using a Ø40 bit until reaching cover thickness,
c) Drilling steel reinforcement using a Ø4 Cobalt bit.
d) Placement of eye terminal on rivet and fixing using a pop rivet gun
e) Checking of electrical continuity with a multimeter
f) Placement of conductive sealant over the connection.
Application of Galvanic Protection – Step C – Placing the ZLA
42. Once all ZLAs have been placed and checked for electrical continuity, their edges shall be
protected by moisture attacking the Hydrogel. In this application Mapeflex PU40 was used. A
layer of width around 30mm and thickness 2-3mm is enough.
Application of Galvanic Protection – Step C – Placing the ZLA
43. Sealing of ZLAs with Mapeflex PU40.
Application of Galvanic Protection – Step C – Placing the ZLA
44. Application of Galvanic Protection – Step D – Placement of Reference Anodes
Placement of two reference electrodes type Ag/AgCl/KCl (Castle Electrodes Ltd, LD10) according
to plans. Reference electrodes allows us to perform depolarisation testing according to EN
12696.
45. It is imperative to do an initial potential measurement to safeguard initialisation and uniform
voltage distribution of the circuit. In this case, values of -417 mV και -380 mV (Ag/AgCl) were
measured from the two reference electrodes.
Εφαρμογή Καθοδικής Προστασίας – Στάδιο Ε – Τοποθέτηση Κυτίων ΕλέγχουApplication of Galvanic Protection – Step E – Junction Boxes and Cable Conduits
46. Complete sealing of ZLA using Mapelastic Smart. Bond strength on ZLA has a declared value of
>1,6 MPa. Sealing protects the anode from consumption due to air oxidation.
Application of Galvanic Protection – Step F – Sealing the Circuit
47. Final form of ZLA application
Application of Galvanic Protection
48. Depolarisation values 7 days after initialisation.
All three EN 12696 requirements
are met.
Instant Off Value R1=-793 mV
Instant Off Value R2=-761 mV
Application of Galvanic Protection – Depolarisation Values - 7 days
49. Instant Off Value R1=-835 mV
Instant Off Value R2=-856 mV
Application of Galvanic Protection – Depolarisation Values - 30 days
Depolarisation values 30 days after initialisation.
All three EN 12696 requirements
are met.
50. Advantages and Disadvantages of ZLAs compared to ICCP
Advantages
Low initial investment cost,
The application does not require specialised equipment and personnel,
Significantly reduces damage due to concrete boring required for ICCP anodes,
Protection can last over 25 years as in the case of carbonation,
Relatively easy calculations based Faraday’s equation,
The anode can be easily replaced,
The potential for hydrogen gas generation is negligible,
It does not require control unit,
Certified according to ΕΝ 12696, BS 7361 and AS 2382.5.
Disadvantages
High cost per year when protection over 40 years is needed.
Limited performance and protection when high current density is required,
It is highly unlikely to cause chloride ions extraction,
It is sensitive to temperature and moisture changes.
52. Facades
Slabs
Beams
Characteristic Applications of ZLAs
Final sealing can be painted or plastered. In the
case of plastering, surface treatment of the
sealant using quartz sand 0.85-1.2 mm is
recommended.
54. List of key materials used in the application
More information can be found in
http://www.mapei.com/GR-EL/
and
http://www.mapei.com/public/GB/linedocument/Cathodic_Protection_GB.pdf