Corrosion of Steel in Concrete: Understanding, Investigation and Repair

Cover
Half Title
Title Page
Copyright Page
Table of Contents
Preface
Illustration Credits
Acknowledgements
Chapter 1 Introduction
References
Chapter 2 Corrosion of Steel in Concrete
2.1 the Corrosion Process
2.2 Black Rust
2.3 Pits, Stray Current and Bacterial Corrosion
2.3.1 Pit Formation
2.3.2 Bacterial Corrosion
2.3.3 Stray-Current-Induced Corrosion
2.3.4 Local vs. General Corrosion (Macrocells vs. Microcells)
2.4 Electrochemistry, Cells and Half Cells
2.5 Conclusions
References
Chapter 3 Causes and Mechanisms of Corrosion in Concrete
3.1 Carbonation
3.1.1 Carbonation Transport Through Concrete
3.2 Chloride Attack
3.2.1 Sources of Chlorides
3.2.2 Chloride Transport Through Concrete
3.2.3 Chloride Attack Mechanism
3.2.4 Macrocell Formation
3.3 Corrosion Damage
3.4 Cracks, Crack Orientation and Corrosion
3.5 the Synergistic Relationship Between Chloride and Carbonation Attack, Chloride Binding and Release
References
Chapter 4 Condition Evaluation
4.1 Desk Study
4.2 Preliminary Survey
4.3 the Detailed Survey
4.4 Available Techniques
4.5 Visual Inspection
4.5.1 Property to be Measured
4.5.2 Equipment and Use
4.5.3 Interpretation
4.5.4 Limitations
4.5.5 Standards and Guidance
4.6 Delamination
4.6.1 Property to be Measured
4.6.2 Equipment and Use
4.6.3 Interpretation
4.6.4 Limitations
4.6.5 Standards and Guidance
4.7 Cover
4.7.1 Property to be Measured
4.7.2 Equipment and Use
4.7.3 Interpretation
4.7.4 Limitations
4.7.5 Standards and Guidance
4.8 Reference Electrode (Half Cell) Potential Measurements
4.8.1 Property to be Measured
4.8.2 Equipment and Use
4.8.3 Interpretation and the Astm Criteria
4.8.4 Reference Electrode Potential Mapping
4.8.5 Cell to Cell Potentials
4.8.6 Limitations
4.8.7 Standards and Guidance Documents
4.9 Carbonation Depth Measurement
4.9.1 Equipment and Use
4.9.2 Interpretation
4.9.3 Limitations
4.9.4 Standards and Guidance Documents
4.10 Chloride Determination
4.10.1 Property to be Measured
4.10.2 Equipment and Use
4.10.3 Interpretation
4.10.4 Standards and Guidance
4.11 Resistivity Measurement
4.11.1 Property to be Measured
4.11.2 Equipment and Use
4.11.3 Interpretation
4.11.4 Limitations
4.11.5 Standards and Guidance
4.12 Corrosion Rate Measurement
4.12.1 Property to be Measured
4.12.2 Equipment and Use – Linear Polarization
4.12.3 Carrying Out a Corrosion Rate Survey
4.12.4 Interpretation – Linear Polarization
4.12.5 Limitations – Linear Polarization
4.12.6 Equipment and Use – Macrocell Techniques
4.12.7 Interpretation – Macrocell Techniques
4.12.8 Standards and Guidance
4.13 Permeability and Absorption Tests
4.13.1 Property to be Measured
4.13.2 Equipment and Use
4.13.3 Interpretation
4.13.4 Limitations
4.13.5 Standards and Guidance
4.14 Concrete Characteristics: Cement Content, Petrography, W/C Ratio
4.15 Ground Penetrating Radar
4.15.1 Property to be Measured
4.15.2 Equipment and Use
4.15.3 Interpretation
4.15.4 Limitations
4.15.5 Standards and Guidance
4.16 Ultrasonic Pulse Velocity
4.16.1 Property to be Measured
4.16.2 Equipment and Use
4.16.3 Interpretation
4.16.4 Limitation
4.16.5 Standards and Guidance
4.17 Impact-echo
4.17.1 Property to be Measured
4.17.2 Equipment and Use
4.17.3 Interpretation
4.17.4 Limitations
4.17.5 Standards and Guidance
4.18 Radiography
4.18.1 Property to be Measured
4.18.2 Equipment and Use
4.18.3 Interpretation
4.18.4 Limitations
4.18.5 Standards and Guidance
4.19 Survey and Assessment Methodology
4.20 Special Conditions – Prestressing and Coated Rebars
4.20.1 Epoxy Coated and Galvanized Reinforcing Bars
4.20.2 Internal Prestressing Cables in Ducts
References
Chapter 5 Corrosion Monitoring
5.1 Regular Surveys to Monitor Corrosion
5.2 Permanent Corrosion Monitoring Systems
5.2.1 Permanent Reference Electrodes
5.2.2 Corrosion Rate by Polarization Resistance Sensors
5.2.3 Corrosion Rate by Galvanic Sensors
5.2.4 Corrosion Rate by Electrical Resistance Sensors
5.2.5 Concrete Resistivity Sensors
5.2.6 Humidity Monitoring
5.2.7 Chloride Content and pH Monitoring
5.3 Remote Monitoring Systems and Data Management
References
Chapter 6 Physical and Chemical Repair and Rehabilitation Techniques
6.1 Concrete Removal and Surface Preparation
6.1.1 Percussion Tools
6.1.2 Hydrojetting
6.1.3 Milling Machines
6.1.4 Comparative Costing
6.1.5 Concrete Damage and Surface Preparation
6.2 Patches
6.2.1 Incipient Anodes
6.2.2 Load Transfer and Structural Issues
6.3 Coatings, Sealers, Membranes and Barriers
6.3.1 Carbonation Repairs
6.3.2 Coatings Against Chlorides, Penetrating Sealers
6.3.3 Waterproofing Membranes
6.3.4 Barriers and Deflection Systems
6.4 Encasement and Overlays
6.5 Sprayed Concrete
6.6 Corrosion Inhibitors
6.6.1 Corrosion Inhibitors for Admixing into Fresh Concrete
6.6.2 Corrosion Inhibitors for Hardened Concrete
6.6.3 Track Record, Case Histories and Monitoring
6.6.4 Summary of the Use of Corrosion Inhibitors in Repairs
6.7 Standards and Guidance on Physical and Chemical Repair
References
Chapter 7 Electrochemical Repair Techniques
7.1 Basic Principles of Electrochemical Techniques
7.2 Cathodic Protection Principles
7.2.1 Theory and Principles – Impressed Current Systems
7.2.2 The History of Cathodic Protection of Steel in Concrete
7.3 Galvanic Anode Systems
7.3.1 Principles of Galvanic Cathodic Protection Systems
7.3.2 Galvanic Anode Systems and Their Development
7.3.3 The Merits and Limitations of Galvanic Cathodic Protection
7.3.4 Hybrid Anodes
7.4 the Components of an Impressed Current Cathodic Protection System
7.4.1 Selection of Anodes and Early Anode Development
7.4.2 Conductive Organic Carbon Loaded Paints
7.4.3 Thermal Sprayed Zinc
7.4.4 Coated Titanium Expanded Mesh in a Concrete Overlay
7.4.5 Coated Titanium Expanded Mesh Ribbon Mortared into Slots Chased into the Concrete
7.4.6 Coated Titanium or Conductive Ceramic Rods, Tubes, etc. in Holes Drilled into the Concrete
7.4.7 Conductive Cementitious Overlay Containing Nickel Plated Carbon Fibres
7.5 Cathodic Protection System Design
7.5.1 Choosing Your Anode
7.5.2 Transformer/rectifiers and Control Systems
7.5.3 Monitoring Probes
7.5.4 Zone Design
7.6 Control Criteria
7.6.1 The IR Drop and Instant Off Measurement
7.7 Standards and Guidance Documents for Cathodic Protection of Steel in Concrete
7.7.1 Ampp Nace Standards
7.7.2 Cen Standard BS EN 12696
7.8 System Installation
7.8.1 Patching for Cathodic Protection
7.8.2 Rebar Connections, Electrical Continuity of Reinforcement and Stray Currents
7.8.3 Monitoring Probe Installation
7.8.4 Anode Installation
7.8.5 Transformer Rectifier and Control System Installation
7.8.6 Initial Energizing
7.8.7 Commissioning
7.8.8 Operation and Maintenance
7.9 Cathodic Protection of Prestressed Concrete
7.10 Cathodic Protection of Epoxy Coated Reinforcing Steel
7.11 Cathodic Protection of Structures with Asr
7.12 Electrochemical Chloride Extraction
7.12.1 Anode Types
7.12.2 Electrolytes
7.12.3 Operating Conditions
7.12.4 End Point Determination
7.12.5 Possible Effects
7.12.6 Alkali-Silica Reactivity
7.12.7 Bond Strength
7.12.8 Results After Treatment: Beneficial Effects of Passing Currents Through Concrete
7.13 Realkalization
7.13.1 Anode Types
7.13.2 Electrolytes
7.13.3 Operating Conditions
7.13.4 End Point Determination
7.13.5 Possible Effects
7.14 Standards and Guidance for Electrochemical Chloride Extraction and Realkalization
7.15 Electro-osmosis
7.16 Comparison of Techniques
7.16.1 Advantages of All Electrochemical Techniques
7.16.2 Disadvantages of All Electrochemical Techniques
7.16.3 Impressed Current Cathodic Protection
7.16.4 Galvanic Cathodic Protection
7.16.5 Electrochemical Chloride Extraction
7.16.6 Realkalization
7.16.7 Costs
References
Chapter 8 Rehabilitation Methodology
8.1 Technical Differences Between Repair Options
8.2 Repair Costs
8.3 Carbonation Options
8.3.1 Patching and Coating
8.3.2 Why Choose Realkalization?
8.4 Chloride Options
8.4.1 Patching and Sealing
8.4.2 Why Choose Impressed Current Cathodic Protection?
8.4.3 Why Choose Galvanic Cathodic Protection?
8.4.4 Why Choose Chloride Removal?
8.4.5 Other Chloride Repair Options
8.5 Standards and Guidance for Selection of Repairs
8.6 Training
References
Chapter 9 Modelling and Calculating Corrosion, Deterioration and Life Cycle Costing of Reinforced Concrete Structures
9.1 Activation Time T₀ Carbonation-induced Corrosion
9.1.1 Determination of Carbonation Rates
9.2 Chloride Ingress Rates (Initiation)
9.2.1 the Parabolic Approximation
9.2.2 Andrade on Resistivity vs Diffusion Coeff
9.2.3 Sampling Variability for Chlorides
9.2.4 Mechanisms Other Than Diffusion
9.3 Rate of Depassivation (Activation)
9.4 Activation Time T₁
9.5 the Clear/stratfull Empirical Calculation
9.6 Corrosion Without Spalling and High Corrosion Rates
9.7 Cracking and Spalling Rates, Condition Indexes and End of Functional Service Life
9.8 Summary of Methodology to Determine Service Life
9.9 Diffusion Models Proposed in Literature
References
Chapter 10 Design for Durability
10.1 Cover, Concrete and Design
10.2 Fusion Bonded Epoxy Coated Rebars
10.2.1 How Does Epoxy Coating Work?
10.2.2 Problems with Epoxy Coating
10.2.3 Advantages and Limitations of Fusion Bonded Epoxy Coated Rebars
10.3 Galvanized Rebar
10.4 Penetrating Sealers
10.5 Other Corrosion Resistant Reinforcement
10.6 Waterproofing Membranes
10.6.1 Advantages and Limitations of Waterproofing Membranes
10.7 Stainless Steel Reinforcement
10.8 Corrosion Inhibitors
10.9 Installing Cathodic Protection in New Structures
10.10 Durable Buildings
10.11 Conclusions
Notes
References
Chapter 11 Sustainability and Future Developments
References
Appendix Sources of Information on Corrosion of Steel in Concrete
Glossary and Index