SlideShare ist ein Scribd-Unternehmen logo
1 von 28
CATHODIC PROTECTION OF
REINFORCED CONCRETE
STRUCTURES
PREPARED BY
Ravi Kumar
Ankan Bairagi
Introduction
 Concrete is a porous (microstructure)
material, which readily absorbs contaminants
from the surrounding environment.
 The water and oxygen in presence of the
chlorides reacts with iron to create corrosion
product on surface of the reinforcing steel.
 The growth in volume of these corrosion
products exerts tensile stress that eventually
causes the concrete to crack.
Contd.
Corrosion of the Reinforcement steel is main
cause for the deterioration of steel which is usually
initiated through chloride attack, or carbonation.
 Carbonation: it refers to the penetration of
atmospheric carbon dioxide into concrete matrix.
 To prevent the corrosion in steel Cathodic
protection method is most widely used
worldwide in the developed countries.
Fig:Chloride attack And Spalling
Ref: Report on Cathodic Protection of reinforced concrete structure at
www.cathodic.co.uk
CORROSION
 Metal that has been extracted from its primary
ore (metal oxide or other free radicals like
sulphides, chlorides) has a natural tendency to
revert to a native form under the action of
oxygen and water.
 The process by which this transformation occurs
is known as corrosion. It is an electrochemical
process. The change from the metallic to the
combined forms occurs by an “anodic reaction”.
Contd..
 The Anode Reaction
Metal Metal ions (dissolved in solution) + electrons
 Common example:
Fe Fe++ + 2e-
This reaction produces free electrons , which pass within
the metal to another site on the metal surface
(Cathode), where it consumed by cathodic reaction.
 The Cathodic Reaction
O2 + 2H2O + 4e- 4OH-
Recombination of these ions at active surface produce
following reaction.
2Fe + O2 + 2H2O = 2Fe (OH)2
Contd.
Methods to Prevent Corrosion
 Barrier Separation
Paints
Polymer coating
Galvanizing Process
Polymer Injection
 Cladding and Chemical Additives
 Electrochemical Method (Cathodic Protection)
 Sacrificial Anodes
 Impressed Current
What is Cathodic Protection (CP) ?
Cathodic protection is a technique used to
control the corrosion of a metal surface by
making it the cathode of an electrochemical cell.
 Principle- The Principle of cathodic protection is
in connecting an external anode to metal to be
protected and the passing of an electric DC
current so that all areas of metal surface
become cathodic and do not corrode.
REF: http://www.cedd.gov.hk/eng/about/organisation/images/pm/image007.jpg
Accessed on 19-09-2013.
Contd.
Elecrochemical
Method
Cathodic
Protection
Sacrificial
Anodes
Impressed
Current
Sacrificial Anode
‱ In usual application a Galvanic anode, a piece of
more electrochemically active metal is attached
to vulnerable metal surface where it is exposed
to the corrosive liquid. The anode metals
gradually dissipate over a period when
connected to and in a common electrolyte, and
are termed as “Sacrificial Anodes”
Contd.
In the case of aluminum anodes, the reaction at the
aluminum surface is: (four aluminum ions plus twelve
free electrons)
 4Al = 4AL+++ + 12 e-
And at the steel surface: (oxygen gas converted to
oxygen ions which combine with water to form hydroxyl
ions).
 3O2 + 12e- + 6H20 = 12OH-
As long as the current (free electrons) arrives at the
cathode (steel) faster than oxygen is arriving, no
corrosion will occur.
Contd.
 Galvanic anodes are selected because they
have a more "active" voltage (more negative
electrochemical potential) than the metal of the
target structure (typically steel)
 The galvanic anode continues to
corrode, consuming the anode material until
eventually it must be replaced.
 Anode Material: Alloys of Zinc, Magnesium and
Aluminum
Pourbix Diagram
Sacrificial Anode Facts
Alloy Base
Weight Loss
per annum
(kg/amp)
Practical
Life
(Years)
Efficiency Use
Magnesium 8 5 50% RC Pipelines
Aluminum 4 10 90% Sea Water
Zinc 12 20 95% Coating
Contd.
Partially corroded sacrificial anode on the hull of a ship.
Ref:http://chemwiki.ucdavis.edu/@api/deki/files/6987/800px-
Sacrificial_anode.jpg?size=bestfit&width=462&height=346&revision=1
Cathodic Protection-Galvanic System
Ref: http://www.wv4c.org
Impressed Current Method
 In this method a potential difference is artificially
created by applying an external positive voltage
to an anode with the negative current return path
through the reinforcement cage and cabling.
 ICCP system use a nodes connected to DC
power source. Usually this will be a cathodic
protection rectifier, which converts an AC power
supply to DC output.
Contd.
 Anode Material can be inert or at least capable
of offering up to a nominal a 20 years life
 This current given to insoluble anode like
graphite stainless steel or scrap iron buried in
soil.
 The negative terminal of D.C is connected to a
pipeline to b protected. The anode is kept in
back-fill.
Impressed Current System
Ref: http://www.wv4c.org
Comparison of CP System
Impressed Current
System
Sacrificial Anode
Longer Anode Life,
Monitoring Required
Simple, No Monitoring &
Control
Current can be controlled No requirement for electrical
isolation
Can be used in any
resistivity environment
Usually Used in lower
resistivity electrolyte
Can Be Used for any type
structure
Used for very small or well
coated structure
Higher Cost Lower Cost
Application
 Pipelines are routinely protected by a coating
supplemented with cathodic Protection.
Ref: https://upload.wikimedia.org/wikipedia/commons/f/f1/Anodes-on-jacket.jpg
Contd.
 Placement of Anode on reinforcement Bar
Cage.
Ref: http://faculty.kfupm.edu.sa/CE
Contd.
‱ The White Patches visible on the ship’s hull are Zinc
Block sacrificial anodes.
Ref:www.usmma.edu/life/sea/images/seayear1.jpg
References
 K G C Berkeley, S Pathmanaban, “Cathodic
Protection of Reinforcement Steel in Concrete”,
Butterworth & Co. (Publishers) Ltd, 1990,
 Alan R Bird, “Cathodic Protection of reinforced
concrete Structures-A Practical Methods of
Arresting Rebar Corrosion” Report published at
WWW.marineandcivil.com.au, pp 1-5
 Baeckman, Schwenck & Prinz, Handbook of
cathodic corrosion protection” 3rd edition 1997
ISBN 0-88415-056-9
Contd.
‱ Dr. S.R Karade & Team, Corrosion Mitigation in RC
structures Through Cathodic Protection, CSIR-CBRI
News Letter,Vol-32 No-1 Jan-March 2012,pp. 1-2
 Denny A.Jones, “Principles and Prevention of
Corrosion” 2nd Edition, Prentice Hall, ISBN 0-13-
359993-0
 V Ashworth, “Principle of Cathodic Protection”
Elsevier B.V, 3rd Edition, Volume-2, pp 10:3-10:28
 Ref: Cathodic Protection of Reinforced Concrete
Structures’, in NACE Technical Report No. 36, 1989,
The Concrete Society, London.

Weitere Àhnliche Inhalte

Was ist angesagt?

Control of corrosion on underwater piles ppt
Control of corrosion on underwater piles pptControl of corrosion on underwater piles ppt
Control of corrosion on underwater piles pptLakshay Saxena
 
Control of corrosion of underwater piles
Control of corrosion of underwater pilesControl of corrosion of underwater piles
Control of corrosion of underwater pilesAvinash Shaw
 
Non destructive test on concrete (ndt)
Non destructive test on concrete (ndt)Non destructive test on concrete (ndt)
Non destructive test on concrete (ndt)Abhishek Gupta
 
Sulphate attack
Sulphate attackSulphate attack
Sulphate attackKrishnagnr
 
Deterioration of concrete ppt
Deterioration of concrete pptDeterioration of concrete ppt
Deterioration of concrete pptwasim shaikh
 
Techniques for repair and protection methods - Repair and rehabilitation of s...
Techniques for repair and protection methods - Repair and rehabilitation of s...Techniques for repair and protection methods - Repair and rehabilitation of s...
Techniques for repair and protection methods - Repair and rehabilitation of s...Shanmugasundaram N
 
A seminar report on control of corrosion on underwater piles
A seminar report on control of corrosion on underwater pilesA seminar report on control of corrosion on underwater piles
A seminar report on control of corrosion on underwater pilesRam Sayan Yadav
 
Deterioration of Concrete Structures
Deterioration of Concrete StructuresDeterioration of Concrete Structures
Deterioration of Concrete StructuresRAMPRASAD KUMAWAT
 
Strength and durability of concrete - Repair and rehabilitation of structures...
Strength and durability of concrete - Repair and rehabilitation of structures...Strength and durability of concrete - Repair and rehabilitation of structures...
Strength and durability of concrete - Repair and rehabilitation of structures...Shanmugasundaram N
 
Deterioration of concrete
Deterioration of concreteDeterioration of concrete
Deterioration of concreteHarikrishna M.S
 
Inspection and maintenance of bridges In India
Inspection and maintenance of bridges In IndiaInspection and maintenance of bridges In India
Inspection and maintenance of bridges In IndiaKhyati Saggu
 
Corrosion Effects in Concrete
Corrosion Effects in ConcreteCorrosion Effects in Concrete
Corrosion Effects in ConcreteYogi Yogesh
 
Workability of Concrete.ppt
Workability of Concrete.pptWorkability of Concrete.ppt
Workability of Concrete.pptRaju S
 
Chemical attack on concrete 2017
Chemical attack on concrete 2017Chemical attack on concrete 2017
Chemical attack on concrete 2017Sagar Vekariya
 
Concrete Corrosion of Reinforcing Steel
Concrete Corrosion of Reinforcing SteelConcrete Corrosion of Reinforcing Steel
Concrete Corrosion of Reinforcing SteelSteven E. Kreeley, EIT
 
Concrete corrosion
Concrete corrosionConcrete corrosion
Concrete corrosionAhmed Faraj
 

Was ist angesagt? (20)

Control of corrosion on underwater piles ppt
Control of corrosion on underwater piles pptControl of corrosion on underwater piles ppt
Control of corrosion on underwater piles ppt
 
Control of corrosion of underwater piles
Control of corrosion of underwater pilesControl of corrosion of underwater piles
Control of corrosion of underwater piles
 
Non destructive test on concrete (ndt)
Non destructive test on concrete (ndt)Non destructive test on concrete (ndt)
Non destructive test on concrete (ndt)
 
Sulphate attack
Sulphate attackSulphate attack
Sulphate attack
 
Deterioration of concrete ppt
Deterioration of concrete pptDeterioration of concrete ppt
Deterioration of concrete ppt
 
Techniques for repair and protection methods - Repair and rehabilitation of s...
Techniques for repair and protection methods - Repair and rehabilitation of s...Techniques for repair and protection methods - Repair and rehabilitation of s...
Techniques for repair and protection methods - Repair and rehabilitation of s...
 
A seminar report on control of corrosion on underwater piles
A seminar report on control of corrosion on underwater pilesA seminar report on control of corrosion on underwater piles
A seminar report on control of corrosion on underwater piles
 
Deterioration of Concrete Structures
Deterioration of Concrete StructuresDeterioration of Concrete Structures
Deterioration of Concrete Structures
 
Epoxy injection crack repair
Epoxy injection crack repairEpoxy injection crack repair
Epoxy injection crack repair
 
Strength and durability of concrete - Repair and rehabilitation of structures...
Strength and durability of concrete - Repair and rehabilitation of structures...Strength and durability of concrete - Repair and rehabilitation of structures...
Strength and durability of concrete - Repair and rehabilitation of structures...
 
Deterioration of concrete
Deterioration of concreteDeterioration of concrete
Deterioration of concrete
 
Inspection and maintenance of bridges In India
Inspection and maintenance of bridges In IndiaInspection and maintenance of bridges In India
Inspection and maintenance of bridges In India
 
Corrosion Effects in Concrete
Corrosion Effects in ConcreteCorrosion Effects in Concrete
Corrosion Effects in Concrete
 
Workability of Concrete.ppt
Workability of Concrete.pptWorkability of Concrete.ppt
Workability of Concrete.ppt
 
Corrosion
CorrosionCorrosion
Corrosion
 
Chemical attack on concrete 2017
Chemical attack on concrete 2017Chemical attack on concrete 2017
Chemical attack on concrete 2017
 
Concrete Corrosion of Reinforcing Steel
Concrete Corrosion of Reinforcing SteelConcrete Corrosion of Reinforcing Steel
Concrete Corrosion of Reinforcing Steel
 
Concrete corrosion
Concrete corrosionConcrete corrosion
Concrete corrosion
 
Structural Strengthening
Structural StrengtheningStructural Strengthening
Structural Strengthening
 
Alkali silica reaction
Alkali silica reactionAlkali silica reaction
Alkali silica reaction
 

Andere mochten auch

Design & Construction Errors- Building Maintenance and Repairs
Design & Construction Errors- Building Maintenance and Repairs Design & Construction Errors- Building Maintenance and Repairs
Design & Construction Errors- Building Maintenance and Repairs Srishti Wakhloo
 
Corrosion Guide
Corrosion GuideCorrosion Guide
Corrosion GuideSwapnilKoshti
 
cathodic protection
cathodic protectioncathodic protection
cathodic protectionAbhishek Mishra
 
QUALITY ASSURANCE
QUALITY ASSURANCEQUALITY ASSURANCE
QUALITY ASSURANCEPharmaceutical
 

Andere mochten auch (7)

Design & Construction Errors- Building Maintenance and Repairs
Design & Construction Errors- Building Maintenance and Repairs Design & Construction Errors- Building Maintenance and Repairs
Design & Construction Errors- Building Maintenance and Repairs
 
Corrosion Guide
Corrosion GuideCorrosion Guide
Corrosion Guide
 
cathodic protection
cathodic protectioncathodic protection
cathodic protection
 
Quality assurance
Quality assuranceQuality assurance
Quality assurance
 
2 quality assurance
2 quality assurance2 quality assurance
2 quality assurance
 
Quality assurance
Quality assuranceQuality assurance
Quality assurance
 
QUALITY ASSURANCE
QUALITY ASSURANCEQUALITY ASSURANCE
QUALITY ASSURANCE
 

Ähnlich wie Cathodic protection of reinforced concrete structures

Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...
Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...
Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...Onyedikachi Martins
 
Corrosion prevention
Corrosion preventionCorrosion prevention
Corrosion preventionHarish Chopra
 
Corrosion prevention
Corrosion preventionCorrosion prevention
Corrosion preventionHarish Chopra
 
(cathodic protection)
(cathodic protection) (cathodic protection)
(cathodic protection) Mohamed Safwat
 
APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...
APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...
APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...IRJET Journal
 
Corrosion engineering
Corrosion engineeringCorrosion engineering
Corrosion engineeringAtul Shinde
 
Interview Cathodic-Protection (Corrosion).ppt
Interview Cathodic-Protection (Corrosion).pptInterview Cathodic-Protection (Corrosion).ppt
Interview Cathodic-Protection (Corrosion).pptArfanAli50
 
Cathodic protection in_practise
Cathodic protection in_practiseCathodic protection in_practise
Cathodic protection in_practiseabdallahbeca
 
IMPRESSED CURRENT CATHODIC PROTECTION
IMPRESSED CURRENT CATHODIC PROTECTIONIMPRESSED CURRENT CATHODIC PROTECTION
IMPRESSED CURRENT CATHODIC PROTECTIONSHAILESH SHUKLA
 
Cathodic and anodic protection
Cathodic and anodic protectionCathodic and anodic protection
Cathodic and anodic protectionTHOMAS THANGADURAI K
 
Corrosion Control By Deposition Of Ca Co3
Corrosion Control By Deposition Of Ca Co3Corrosion Control By Deposition Of Ca Co3
Corrosion Control By Deposition Of Ca Co3mahfoodhshuely
 
Hitesh cathodic protection
Hitesh cathodic protectionHitesh cathodic protection
Hitesh cathodic protectionHitesh Mahajan
 
13 Cathodic Protection
13 Cathodic Protection13 Cathodic Protection
13 Cathodic ProtectionWorley parsons
 
cathodic protection and maintenance requred 3.pptx
cathodic protection and maintenance requred 3.pptxcathodic protection and maintenance requred 3.pptx
cathodic protection and maintenance requred 3.pptxMAHMOUDMOHAMED431205
 
Corrosion Control satyam.pptx
Corrosion Control satyam.pptxCorrosion Control satyam.pptx
Corrosion Control satyam.pptxAzharUddin213116
 
Corrosion and Degradation of Materials-chapter 16
Corrosion and Degradation of Materials-chapter 16Corrosion and Degradation of Materials-chapter 16
Corrosion and Degradation of Materials-chapter 16ssuser2fec01
 
Material Technology
Material TechnologyMaterial Technology
Material TechnologyMalaysia
 

Ähnlich wie Cathodic protection of reinforced concrete structures (20)

Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...
Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...
Design of a Cathodic Protection System for Corrosion Prevention of a Pipeline...
 
Cathodic protection
Cathodic protectionCathodic protection
Cathodic protection
 
Corrosion prevention
Corrosion preventionCorrosion prevention
Corrosion prevention
 
Corrosion prevention
Corrosion preventionCorrosion prevention
Corrosion prevention
 
(cathodic protection)
(cathodic protection) (cathodic protection)
(cathodic protection)
 
Corrosion
CorrosionCorrosion
Corrosion
 
APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...
APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...
APPLICATION OF WASTE NATURAL MATERIAL FOR CORROSION INHIBITION OF LOW CARBON ...
 
Corrosion engineering
Corrosion engineeringCorrosion engineering
Corrosion engineering
 
Interview Cathodic-Protection (Corrosion).ppt
Interview Cathodic-Protection (Corrosion).pptInterview Cathodic-Protection (Corrosion).ppt
Interview Cathodic-Protection (Corrosion).ppt
 
Cathodic protection in_practise
Cathodic protection in_practiseCathodic protection in_practise
Cathodic protection in_practise
 
IMPRESSED CURRENT CATHODIC PROTECTION
IMPRESSED CURRENT CATHODIC PROTECTIONIMPRESSED CURRENT CATHODIC PROTECTION
IMPRESSED CURRENT CATHODIC PROTECTION
 
Cathodic and anodic protection
Cathodic and anodic protectionCathodic and anodic protection
Cathodic and anodic protection
 
Corrosion Control By Deposition Of Ca Co3
Corrosion Control By Deposition Of Ca Co3Corrosion Control By Deposition Of Ca Co3
Corrosion Control By Deposition Of Ca Co3
 
Hitesh cathodic protection
Hitesh cathodic protectionHitesh cathodic protection
Hitesh cathodic protection
 
13 Cathodic Protection
13 Cathodic Protection13 Cathodic Protection
13 Cathodic Protection
 
Corrosion
CorrosionCorrosion
Corrosion
 
cathodic protection and maintenance requred 3.pptx
cathodic protection and maintenance requred 3.pptxcathodic protection and maintenance requred 3.pptx
cathodic protection and maintenance requred 3.pptx
 
Corrosion Control satyam.pptx
Corrosion Control satyam.pptxCorrosion Control satyam.pptx
Corrosion Control satyam.pptx
 
Corrosion and Degradation of Materials-chapter 16
Corrosion and Degradation of Materials-chapter 16Corrosion and Degradation of Materials-chapter 16
Corrosion and Degradation of Materials-chapter 16
 
Material Technology
Material TechnologyMaterial Technology
Material Technology
 

KĂŒrzlich hochgeladen

Introduction to ArtificiaI Intelligence in Higher Education
Introduction to ArtificiaI Intelligence in Higher EducationIntroduction to ArtificiaI Intelligence in Higher Education
Introduction to ArtificiaI Intelligence in Higher Educationpboyjonauth
 
APM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across SectorsAPM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across SectorsAssociation for Project Management
 
Crayon Activity Handout For the Crayon A
Crayon Activity Handout For the Crayon ACrayon Activity Handout For the Crayon A
Crayon Activity Handout For the Crayon AUnboundStockton
 
Grant Readiness 101 TechSoup and Remy Consulting
Grant Readiness 101 TechSoup and Remy ConsultingGrant Readiness 101 TechSoup and Remy Consulting
Grant Readiness 101 TechSoup and Remy ConsultingTechSoup
 
The basics of sentences session 2pptx copy.pptx
The basics of sentences session 2pptx copy.pptxThe basics of sentences session 2pptx copy.pptx
The basics of sentences session 2pptx copy.pptxheathfieldcps1
 
microwave assisted reaction. General introduction
microwave assisted reaction. General introductionmicrowave assisted reaction. General introduction
microwave assisted reaction. General introductionMaksud Ahmed
 
_Math 4-Q4 Week 5.pptx Steps in Collecting Data
_Math 4-Q4 Week 5.pptx Steps in Collecting Data_Math 4-Q4 Week 5.pptx Steps in Collecting Data
_Math 4-Q4 Week 5.pptx Steps in Collecting DataJhengPantaleon
 
Concept of Vouching. B.Com(Hons) /B.Compdf
Concept of Vouching. B.Com(Hons) /B.CompdfConcept of Vouching. B.Com(Hons) /B.Compdf
Concept of Vouching. B.Com(Hons) /B.CompdfUmakantAnnand
 
Incoming and Outgoing Shipments in 1 STEP Using Odoo 17
Incoming and Outgoing Shipments in 1 STEP Using Odoo 17Incoming and Outgoing Shipments in 1 STEP Using Odoo 17
Incoming and Outgoing Shipments in 1 STEP Using Odoo 17Celine George
 
Software Engineering Methodologies (overview)
Software Engineering Methodologies (overview)Software Engineering Methodologies (overview)
Software Engineering Methodologies (overview)eniolaolutunde
 
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions  for the students and aspirants of Chemistry12th.pptxOrganic Name Reactions  for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptxVS Mahajan Coaching Centre
 
“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...
“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...
“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...Marc Dusseiller Dusjagr
 
Presiding Officer Training module 2024 lok sabha elections
Presiding Officer Training module 2024 lok sabha electionsPresiding Officer Training module 2024 lok sabha elections
Presiding Officer Training module 2024 lok sabha electionsanshu789521
 
Solving Puzzles Benefits Everyone (English).pptx
Solving Puzzles Benefits Everyone (English).pptxSolving Puzzles Benefits Everyone (English).pptx
Solving Puzzles Benefits Everyone (English).pptxOH TEIK BIN
 
BASLIQ CURRENT LOOKBOOK LOOKBOOK(1) (1).pdf
BASLIQ CURRENT LOOKBOOK  LOOKBOOK(1) (1).pdfBASLIQ CURRENT LOOKBOOK  LOOKBOOK(1) (1).pdf
BASLIQ CURRENT LOOKBOOK LOOKBOOK(1) (1).pdfSoniaTolstoy
 
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdfArihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdfchloefrazer622
 
Call Girls in Dwarka Mor Delhi Contact Us 9654467111
Call Girls in Dwarka Mor Delhi Contact Us 9654467111Call Girls in Dwarka Mor Delhi Contact Us 9654467111
Call Girls in Dwarka Mor Delhi Contact Us 9654467111Sapana Sha
 

KĂŒrzlich hochgeladen (20)

Introduction to ArtificiaI Intelligence in Higher Education
Introduction to ArtificiaI Intelligence in Higher EducationIntroduction to ArtificiaI Intelligence in Higher Education
Introduction to ArtificiaI Intelligence in Higher Education
 
APM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across SectorsAPM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across Sectors
 
Crayon Activity Handout For the Crayon A
Crayon Activity Handout For the Crayon ACrayon Activity Handout For the Crayon A
Crayon Activity Handout For the Crayon A
 
Grant Readiness 101 TechSoup and Remy Consulting
Grant Readiness 101 TechSoup and Remy ConsultingGrant Readiness 101 TechSoup and Remy Consulting
Grant Readiness 101 TechSoup and Remy Consulting
 
Model Call Girl in Bikash Puri Delhi reach out to us at 🔝9953056974🔝
Model Call Girl in Bikash Puri  Delhi reach out to us at 🔝9953056974🔝Model Call Girl in Bikash Puri  Delhi reach out to us at 🔝9953056974🔝
Model Call Girl in Bikash Puri Delhi reach out to us at 🔝9953056974🔝
 
The basics of sentences session 2pptx copy.pptx
The basics of sentences session 2pptx copy.pptxThe basics of sentences session 2pptx copy.pptx
The basics of sentences session 2pptx copy.pptx
 
microwave assisted reaction. General introduction
microwave assisted reaction. General introductionmicrowave assisted reaction. General introduction
microwave assisted reaction. General introduction
 
_Math 4-Q4 Week 5.pptx Steps in Collecting Data
_Math 4-Q4 Week 5.pptx Steps in Collecting Data_Math 4-Q4 Week 5.pptx Steps in Collecting Data
_Math 4-Q4 Week 5.pptx Steps in Collecting Data
 
Concept of Vouching. B.Com(Hons) /B.Compdf
Concept of Vouching. B.Com(Hons) /B.CompdfConcept of Vouching. B.Com(Hons) /B.Compdf
Concept of Vouching. B.Com(Hons) /B.Compdf
 
Incoming and Outgoing Shipments in 1 STEP Using Odoo 17
Incoming and Outgoing Shipments in 1 STEP Using Odoo 17Incoming and Outgoing Shipments in 1 STEP Using Odoo 17
Incoming and Outgoing Shipments in 1 STEP Using Odoo 17
 
Software Engineering Methodologies (overview)
Software Engineering Methodologies (overview)Software Engineering Methodologies (overview)
Software Engineering Methodologies (overview)
 
Staff of Color (SOC) Retention Efforts DDSD
Staff of Color (SOC) Retention Efforts DDSDStaff of Color (SOC) Retention Efforts DDSD
Staff of Color (SOC) Retention Efforts DDSD
 
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions  for the students and aspirants of Chemistry12th.pptxOrganic Name Reactions  for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
 
“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...
“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...
“Oh GOSH! Reflecting on Hackteria's Collaborative Practices in a Global Do-It...
 
Presiding Officer Training module 2024 lok sabha elections
Presiding Officer Training module 2024 lok sabha electionsPresiding Officer Training module 2024 lok sabha elections
Presiding Officer Training module 2024 lok sabha elections
 
CĂłdigo Creativo y Arte de Software | Unidad 1
CĂłdigo Creativo y Arte de Software | Unidad 1CĂłdigo Creativo y Arte de Software | Unidad 1
CĂłdigo Creativo y Arte de Software | Unidad 1
 
Solving Puzzles Benefits Everyone (English).pptx
Solving Puzzles Benefits Everyone (English).pptxSolving Puzzles Benefits Everyone (English).pptx
Solving Puzzles Benefits Everyone (English).pptx
 
BASLIQ CURRENT LOOKBOOK LOOKBOOK(1) (1).pdf
BASLIQ CURRENT LOOKBOOK  LOOKBOOK(1) (1).pdfBASLIQ CURRENT LOOKBOOK  LOOKBOOK(1) (1).pdf
BASLIQ CURRENT LOOKBOOK LOOKBOOK(1) (1).pdf
 
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdfArihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
 
Call Girls in Dwarka Mor Delhi Contact Us 9654467111
Call Girls in Dwarka Mor Delhi Contact Us 9654467111Call Girls in Dwarka Mor Delhi Contact Us 9654467111
Call Girls in Dwarka Mor Delhi Contact Us 9654467111
 

Cathodic protection of reinforced concrete structures

  • 1. CATHODIC PROTECTION OF REINFORCED CONCRETE STRUCTURES PREPARED BY Ravi Kumar Ankan Bairagi
  • 2. Introduction  Concrete is a porous (microstructure) material, which readily absorbs contaminants from the surrounding environment.  The water and oxygen in presence of the chlorides reacts with iron to create corrosion product on surface of the reinforcing steel.  The growth in volume of these corrosion products exerts tensile stress that eventually causes the concrete to crack.
  • 3. Contd. Corrosion of the Reinforcement steel is main cause for the deterioration of steel which is usually initiated through chloride attack, or carbonation.  Carbonation: it refers to the penetration of atmospheric carbon dioxide into concrete matrix.  To prevent the corrosion in steel Cathodic protection method is most widely used worldwide in the developed countries.
  • 4. Fig:Chloride attack And Spalling Ref: Report on Cathodic Protection of reinforced concrete structure at www.cathodic.co.uk
  • 5. CORROSION  Metal that has been extracted from its primary ore (metal oxide or other free radicals like sulphides, chlorides) has a natural tendency to revert to a native form under the action of oxygen and water.  The process by which this transformation occurs is known as corrosion. It is an electrochemical process. The change from the metallic to the combined forms occurs by an “anodic reaction”.
  • 6. Contd..  The Anode Reaction Metal Metal ions (dissolved in solution) + electrons  Common example: Fe Fe++ + 2e- This reaction produces free electrons , which pass within the metal to another site on the metal surface (Cathode), where it consumed by cathodic reaction.  The Cathodic Reaction O2 + 2H2O + 4e- 4OH- Recombination of these ions at active surface produce following reaction. 2Fe + O2 + 2H2O = 2Fe (OH)2
  • 8. Methods to Prevent Corrosion  Barrier Separation Paints Polymer coating Galvanizing Process Polymer Injection  Cladding and Chemical Additives  Electrochemical Method (Cathodic Protection)  Sacrificial Anodes  Impressed Current
  • 9. What is Cathodic Protection (CP) ? Cathodic protection is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.  Principle- The Principle of cathodic protection is in connecting an external anode to metal to be protected and the passing of an electric DC current so that all areas of metal surface become cathodic and do not corrode.
  • 12. Sacrificial Anode ‱ In usual application a Galvanic anode, a piece of more electrochemically active metal is attached to vulnerable metal surface where it is exposed to the corrosive liquid. The anode metals gradually dissipate over a period when connected to and in a common electrolyte, and are termed as “Sacrificial Anodes”
  • 13. Contd. In the case of aluminum anodes, the reaction at the aluminum surface is: (four aluminum ions plus twelve free electrons)  4Al = 4AL+++ + 12 e- And at the steel surface: (oxygen gas converted to oxygen ions which combine with water to form hydroxyl ions).  3O2 + 12e- + 6H20 = 12OH- As long as the current (free electrons) arrives at the cathode (steel) faster than oxygen is arriving, no corrosion will occur.
  • 14.
  • 15. Contd.  Galvanic anodes are selected because they have a more "active" voltage (more negative electrochemical potential) than the metal of the target structure (typically steel)  The galvanic anode continues to corrode, consuming the anode material until eventually it must be replaced.  Anode Material: Alloys of Zinc, Magnesium and Aluminum
  • 17. Sacrificial Anode Facts Alloy Base Weight Loss per annum (kg/amp) Practical Life (Years) Efficiency Use Magnesium 8 5 50% RC Pipelines Aluminum 4 10 90% Sea Water Zinc 12 20 95% Coating
  • 18. Contd. Partially corroded sacrificial anode on the hull of a ship. Ref:http://chemwiki.ucdavis.edu/@api/deki/files/6987/800px- Sacrificial_anode.jpg?size=bestfit&width=462&height=346&revision=1
  • 20. Impressed Current Method  In this method a potential difference is artificially created by applying an external positive voltage to an anode with the negative current return path through the reinforcement cage and cabling.  ICCP system use a nodes connected to DC power source. Usually this will be a cathodic protection rectifier, which converts an AC power supply to DC output.
  • 21. Contd.  Anode Material can be inert or at least capable of offering up to a nominal a 20 years life  This current given to insoluble anode like graphite stainless steel or scrap iron buried in soil.  The negative terminal of D.C is connected to a pipeline to b protected. The anode is kept in back-fill.
  • 22. Impressed Current System Ref: http://www.wv4c.org
  • 23. Comparison of CP System Impressed Current System Sacrificial Anode Longer Anode Life, Monitoring Required Simple, No Monitoring & Control Current can be controlled No requirement for electrical isolation Can be used in any resistivity environment Usually Used in lower resistivity electrolyte Can Be Used for any type structure Used for very small or well coated structure Higher Cost Lower Cost
  • 24. Application  Pipelines are routinely protected by a coating supplemented with cathodic Protection. Ref: https://upload.wikimedia.org/wikipedia/commons/f/f1/Anodes-on-jacket.jpg
  • 25. Contd.  Placement of Anode on reinforcement Bar Cage. Ref: http://faculty.kfupm.edu.sa/CE
  • 26. Contd. ‱ The White Patches visible on the ship’s hull are Zinc Block sacrificial anodes. Ref:www.usmma.edu/life/sea/images/seayear1.jpg
  • 27. References  K G C Berkeley, S Pathmanaban, “Cathodic Protection of Reinforcement Steel in Concrete”, Butterworth & Co. (Publishers) Ltd, 1990,  Alan R Bird, “Cathodic Protection of reinforced concrete Structures-A Practical Methods of Arresting Rebar Corrosion” Report published at WWW.marineandcivil.com.au, pp 1-5  Baeckman, Schwenck & Prinz, Handbook of cathodic corrosion protection” 3rd edition 1997 ISBN 0-88415-056-9
  • 28. Contd. ‱ Dr. S.R Karade & Team, Corrosion Mitigation in RC structures Through Cathodic Protection, CSIR-CBRI News Letter,Vol-32 No-1 Jan-March 2012,pp. 1-2  Denny A.Jones, “Principles and Prevention of Corrosion” 2nd Edition, Prentice Hall, ISBN 0-13- 359993-0  V Ashworth, “Principle of Cathodic Protection” Elsevier B.V, 3rd Edition, Volume-2, pp 10:3-10:28  Ref: Cathodic Protection of Reinforced Concrete Structures’, in NACE Technical Report No. 36, 1989, The Concrete Society, London.