Corrosion and Protection of Reinforced Concrete

✍ Scribed by Brian Cherry and Warren Green

• Publisher: CRC Press
• Year: 2021
• Tongue: English
• Leaves: 403
• Category: Library

✦ Synopsis

Reinforced concrete is the most widely used construction material in the world, and extended performance is rightly expected. Many structures are in aggressive environments, of critical importance and may be irreplaceable, so repair and protection are vital. This book surveys deterioration of concrete, particularly corrosion of the steel reinforcement, and the various chemical, biological, physical and mechanical causes of deterioration. It outlines condition survey and diagnosis techniques by on-site and laboratory measurements. It sets out mechanical methods of protection and repair, such as patching, inhibitors, coatings, penetrants and structural strengthening as well as cathodic protection and other electrochemical methods. This book also gives guidance on preventative measures including concrete technology and construction considerations, coatings and penetrants, alternate reinforcement, permanent corrosion monitoring and durability planning aspects.

Asset managers, port engineers, bridge maintenance managers, building managers, heritage structure engineers, plant engineers, consulting engineers, architects, specialist contractors and construction material suppliers who have the task of resolving problems of corrosion of steel reinforced concrete elements will find this book an extremely useful resource. It will also be a valuable reference for students at postgraduate level.

Authors

The late Professor Brian Cherry of Monash University, Melbourne, Australia was one of the world’s leading corrosion science and engineering educators and researchers.

Warren Green of Vinsi Partners, Sydney, Australia is a corrosion engineer and materials scientist. He is also an Adjunct Associate Professor.

✦ Table of Contents

Cover
Half Title
Title Page
Copyright Page
Table of Contents
Preface
Authors
Chapter 1: Steel-reinforced concrete characteristics
1.1 Concrete and reinforced concrete
1.2 The structure of concrete
1.3 Cements and the cementing action
1.3.1 General
1.3.2 Heat of hydration
1.3.3 Rate of strength development
1.4 Supplementary cementitious materials – blended cements
1.4.1 General
1.4.2 Fly ash
1.4.3 Slag
1.4.4 Silica fume
1.4.5 Triple blends
1.5 Aggregates
1.5.1 General
1.5.2 The design of a concrete mix
1.5.3 Estimation of fine aggregate content and mechanical properties
1.6 Mixing and curing water
1.7 Admixtures
1.7.1 Air entraining admixtures
1.7.2 Set retarding admixtures
1.7.3 Set accelerating admixtures
1.7.4 Water reducing and set retarding admixtures
1.7.5 Water reducing and set accelerating admixtures
1.7.6 High range water reducing admixtures
1.7.7 Waterproofing agents
1.7.8 Other
1.8 Steel reinforcement
1.8.1 Background
1.8.2 Conventional steel reinforcement
1.8.3 Prestressing steel reinforcement
1.9 Fibre-reinforced concrete
References
Chapter 2: Concrete deterioration mechanisms (A)
2.1 Reinforced concrete deterioration
2.2 Cracking
2.2.1 General
2.2.2 Plastic settlement cracking
2.2.3 Plastic shrinkage cracking
2.2.4 Early thermal contraction cracking
2.2.5 Drying shrinkage cracking
2.2.6 Crazing
2.2.7 Alkali aggregate reaction cracking
2.3 Penetrability
2.4 Chemical deterioration
2.4.1 General
2.4.2 Alkali aggregate reaction
2.4.3 Delayed ettringite formation
2.4.4 Sulphate attack
2.4.5 Acid sulphate soils
2.4.6 Thaumasite sulphate attack
2.4.7 Acid attack
2.4.8 Aggressive (Dissolved) carbon dioxide attack
2.4.9 Seawater attack
2.4.10 Leaching and efflorescence
2.4.11 Physical salt attack
2.4.12 Other chemical attack
References
Chapter 3: Concrete deterioration mechanisms (B)
3.1 Biological deterioration
3.1.1 Bacteria
3.1.2 Fungi
3.1.3 Algae
3.1.4 Slimes
3.1.5 Biofilms
3.2 Physical deterioration
3.2.1 Freeze-thaw
3.2.2 Fire
3.3 Mechanical deterioration
3.3.1 Abrasion
3.3.2 Erosion
3.3.3 Cavitation
3.3.4 Impact
3.4 Structural deterioration
3.4.1 Overloading
3.4.2 Settlement
3.4.3 Fatigue
3.4.4 Other
3.5 Fire damaged concrete
3.5.1 General
3.5.2 Effects on concrete
3.5.3 Visual concrete fire damage classification
3.5.4 Effect on reinforcement and prestressing steel
3.6 Examination of sites
References
Chapter 4: Corrosion of reinforcement (A)
4.1 Background
4.2 Portland cement and blended cement binders
4.3 Alkaline environment in concrete
4.4 Physical barrier provided by concrete
4.5 Passivity and the passive film
4.5.1 Background
4.5.2 Thermodynamics
4.5.3 Kinetics
4.5.4 Film formation
4.5.5 Film composition
4.5.6 Film thickness
4.5.7 Models and theories
4.6 Reinforcement corrosion
4.6.1 Loss of passivity and corrosion of steel in concrete
4.6.2 Uniform (Microcell) corrosion and pitting (Macrocell) corrosion
4.6.3 Corrosion products composition – chloride-induced corrosion
4.6.4 Corrosion products composition – carbonation-induced corrosion
4.6.5 Corrosion products development – visible damage
4.6.6 Corrosion products development – no visible damage
4.7 Chloride-induced corrosion
4.7.1 General
4.7.2 Passive film breakdown/pit initiation
4.7.3 Metastable pitting
4.7.4 Pit growth/pit propagation
4.7.4.1 General
4.7.4.2 Chemical conditions within propagating pits
4.7.5 Reinforcing steel quality
4.7.5.1 Metallurgy
4.7.5.2 Defects
4.7.6 Chloride threshold concentrations
4.7.7 Chloride/hydroxyl ratio
4.8 Carbonation-induced corrosion
4.9 Leaching-induced corrosion
4.10 Stray and interference current-induced corrosion
4.10.1 General
4.10.2 Ground currents
4.10.3 Interference currents
4.10.4 Local corrosion due to stray or interference currents
References
Chapter 5: Corrosion of reinforcement (B)
5.1 Thermodynamics of corrosion
5.1.1 Background
5.1.2 The driving potential – the Nernst equation
5.1.3 The potential – pH diagram
5.2 Kinetics of corrosion
5.2.1 Background
5.2.2 Polarisation
5.2.3 Investigation of the corrosion state
5.2.4 Pitting corrosion
5.2.5 Oxygen availability
5.2.6 Polarisation of the anodic process
5.2.7 Resistance between anodic and cathodic sites
5.2.8 Potential difference between anodic and cathodic sites
5.3 Reinforcement corrosion progress
5.4 Modelling chloride-induced corrosion initiation
5.5 Modelling carbonation-induced corrosion initiation
5.6 Modelling corrosion propagation
5.6.1 Background
5.6.2 Corrosion damage criterion
5.6.3 Factors affecting corrosion rates
5.6.4 Corrosion rates – chloride contaminated concrete
5.6.5 Corrosion rates – carbonated concrete
5.6.6 Length of corrosion propagation period
5.6.6.1 Background
5.6.6.2 General model
5.6.6.3 Andrade (2014) model
5.6.6.4 Andrade (2017) model
5.7 Design life achievement
References
Chapter 6: Condition survey and diagnosis (A) – on-site measurements
6.1 Planning a condition survey
6.2 Visual inspection
6.3 Cracks
6.4 Delamination detection
6.5 Concrete cover
6.6 Electrochemical measurements
6.6.1 Electrode (half-cell) potential mapping
6.6.2 Polarisation resistance
6.7 Concrete resistivity
6.8 Other measurements
6.8.1 Rebound hammer
6.8.2 Ultrasonic pulse velocity
6.8.3 Ultrasonic pulse echo
6.8.4 Impact echo
6.8.5 Ground penetrating radar
6.9 Carbonation depth
6.10 Concrete sampling
6.10.1 General
6.10.2 Wet diamond coring
6.10.3 Drilled Dust Samples
6.11 Representativeness of investigations, testings, and sampling
References
Chapter 7: Condition survey and diagnosis (B) – laboratory measurements
7.1 General
7.2 Cement (Binder) content and composition
7.3 Air content
7.4 Water/cement (binder) ratio
7.5 SCM content and composition
7.6 Water absorption, sorption, and permeability
7.7 Depth of chloride penetration
7.8 Sulphate analysis
7.9 Alkali aggregate reaction
7.10 Alkali content
7.11 Delayed ettringite formation
7.12 Acid attack
7.13 Chemical attack
7.14 Microbial analysis
7.15 Physical deterioration determination
7.16 Petrographic examination
7.17 Compressive strength
7.18 Reporting
7.18.1 Background
7.18.2 Commission/scope of services
7.18.3 Technical background
7.18.4 Site investigation
7.18.5 Hypothesis
7.18.6 Laboratory testing
7.18.7 Commentary on laboratory results
7.18.8 Conclusions and recommendations
References
Chapter 8: Repair and protection (A) – mechanical methods
8.1 Introduction
8.2 Crack repair
8.3 Repair and protection options
8.4 Patch repair
8.4.1 Stages in the process
8.4.2 Breakout
8.4.3 Rebar coatings
8.4.4 Bonding agents
8.4.5 Patching materials
8.4.6 Equipment and workmanship
8.5 Sprayed concrete (Shotcrete/Gunite)
8.6 Recasting with new concrete
8.7 Inhibitors
8.8 Coatings and penetrants
8.8.1 Anti-carbonation coatings
8.8.2 Chloride-resistant coatings
8.8.3 Penetrants
8.9 Structural strengthening
8.10 Pile jacketing
References
Chapter 9: Repair and protection (B) – cathodic protection
9.1 Introduction
9.2 History of cathodic protection
9.3 Impressed current cathodic protection
9.4 Galvanic cathodic protection
9.5 The application of cathodic protection
9.6 Impressed current anodes
9.6.1 Historic
9.6.2 Soil/water anodes
9.6.3 Mesh anodes
9.6.4 Ribbon/grid anodes
9.6.5 Discrete anodes
9.6.6 Arc sprayed zinc
9.6.7 Conductive organic coatings
9.6.8 Remote (soil/water) anodes
9.7 Galvanic anodes
9.7.1 Remote (soil/water) anodes
9.7.2 Thermally sprayed metals
9.7.3 Zinc mesh with fibreglass jacket
9.7.4 Zinc sheet anodes
9.8 The actions of cathodic protection
9.8.1 General
9.8.2 Thermodynamics
9.8.3 Kinetics
9.9 Criteria for cathodic protection
9.9.1 Background
9.9.2 Potential criterion
9.9.3 Instantaneous off measurements
9.9.4 300 mV shift criterion
9.9.5 100 mV potential decay (polarisation) criterion
9.9.6 AS 2832.5 criteria
9.9.7 ISO 12696 criteria
9.9.8 Other standards
9.9.9 CP criteria are proven
9.10 Selection and design of cathodic protection systems
9.10.1 General considerations
9.10.2 General design considerations
9.10.3 Current density
9.10.4 Anode layout
9.10.5 Power requirements
9.10.5.1 General
9.10.5.2 Anode resistance
9.10.5.3 Circuit resistance
9.10.5.4 Cathodic polarisation (back emf)
9.10.5.5 Power supply
9.11 Stray current and interference corrosion
9.11.1 General
9.11.2 Regulatory requirements
9.12 Commissioning
9.13 System documentation
9.13.1 Quality and test records
9.13.2 Installation and commissioning report
9.13.3 Operation and maintenance manual
9.14 Operational
9.14.1 Warranty period
9.14.2 Monitoring
9.14.3 System registration
9.15 Cathodic prevention
References
Chapter 10: Repair and protection (C) – electrochemical methods
10.1 Galvanic electrochemical treatments
10.1.1 Background
10.1.2 Discrete zinc anodes in patch repairs
10.1.3 Distributed discrete zinc anodes
10.1.4 Performance limitations
10.1.5 Performance assessment
10.2 Hybrid electrochemical treatments
10.2.1 Background
10.2.2 First generation system
10.2.3 Second generation system
10.2.4 Performance assessment and limitations
10.3 Electrochemical chloride extraction
10.4 Electrochemical realkalisation
10.5 Repair and protection options – costs assessment approaches
10.6 Repair and protection options – technical assessment approaches
10.6.1 General
10.6.2 ‘Do nothing’ option
10.6.3 Scenario analyses approach
References
Chapter 11: Preventative measures
11.1 Introduction
11.2 Concrete technology aspects
11.2.1 General
11.2.2 Mix design/mix selection
11.2.3 Mix selection process
11.2.4 Binder types
11.2.5 Water/cement (water/binder) ratio
11.2.6 Concrete strength
11.3 Construction considerations
11.3.1 General
11.3.2 The 5 Cs/Pentagon of Cs
11.4 Coatings and penetrants
11.4.1 General
11.4.2 Organic coatings
11.4.3 Penetrants
11.4.4 Pore blocking treatments
11.4.5 Cementitious overlays
11.4.6 Sheet membranes
11.5 Coated and alternate reinforcement
11.5.1 General
11.5.2 Galvanised reinforcement
11.5.3 Epoxy coated reinforcement
11.5.4 Stainless steel reinforcement
11.5.5 Metallic clad reinforcement
11.5.6 Non-metallic reinforcement
11.6 Permanent corrosion monitoring
References
Chapter 12: Durability planning aspects
12.1 Significance of durability
12.2 Durability philosophy
12.3 Phases in the life of a structure
12.4 Owner requirements
12.5 Designer requirements
12.6 Contractor requirements
12.7 Operator/maintainer requirements
12.8 Limit states
12.9 Service life design
12.10 Durability assessment – buried aggressive exposure – 100-year design life
12.11 Durability assessment – marine exposure – 100-, 150-, & 200-year design lives
References
Index