Corrosion and Protection of Reinforced Concrete

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