Durability of Reinforced Concrete From Composition to Protection : Selected Papers of the 6th International RILEM PhD Workshop Held in Delft, The Netherlands, July 4-5, 2013

This book presents key advances in the modeling of reinforcement corrosion and concrete durability. It also examines various further aspects of reinforcement corrosion and concrete durability, striking a balance between modeling and testing. Particular attention is paid to innovative treatments for avoiding deterioration, and to methods for modeling performance in a real environment. Some basic aspects related to non-destructive testing techniques are also discussed. Deterioration-related topics addressed in the book include the basis for modeling alkali-silica reactions, chloride diffusion and the development of concrete microstructure; measurement-related topics include cathodic protection, polarization resistance and resistivity. A combined approach using the AFM technique and polarization measurements is examined, and the relation between cracking and corrosion and the treatment of concrete with hydrophobes or innovative products such as hydrotalcite is also discussed. Contents 6 Visualisation of the Electrical Resistivity Distribution of Reinforced Concrete 8 1 Introduction 8 2 Electrode Configurations 10 3 Electrical Resistivity Tomography 12 4 Results 13 5 Conclusions 16 References 16 Electronic and Electrolytic Conduction of Cement Pastes with Additions of Carbonaceous Materials 18 1 Introduction 18 2 Experimental Procedure 19 2.1 Materials and Specimen Preparation 19 2.2 Techniques 20 3 Results 21 3.1 Measurement of the Electrical Resistance 21 4 Discussion 25 4.1 Types of Measurement and Conduction Mechanisms 25 4.2 Effect of the Amount of Addition: Percolation Initiation for Electrical Conduction 29 4.3 Effect of the RH in the Measurements 29 4.4 Effect of the Fiber Aspect Ratio the Measurements 30 5 Conclusions 31 References 31 Influence of Anolyte on Lithium Migration in Concrete 33 1 Introduction 33 2 Experimental 34 2.1 Materials and Specimen Preparation 34 2.2 Apparatus and Procedure 34 3 Results 36 4 Concluding Remarks 40 References 40 Durability of Hydrophobic Treatments on Concrete 41 1 Introduction 41 2 Materials, Sample Preparation, and Measuring Method 42 3 Effects of Different Environmental Conditions on the Hydrophobic Layer Thickness 44 3.1 UV Radiation 44 3.2 Storing in Alkaline Solution 45 3.3 Artificial Carbonation 45 4 Efficacy of the Hydrophobic Layer 47 5 Conclusions and Outlook 48 References 49 Steel Corrosion Rate Measurements in FA Concrete Using Three Electrochemical Techniques 50 1 Introduction 50 2 Materials 51 3 Experimental Set Up 52 3.1 Aggressive Exposure Environments 52 3.1.1 Chloride Ion Exposure Environment 52 3.1.2 Carbon Dioxide Exposure 52 3.1.3 Chloride Ion and Carbon Dioxide Exposure 52 3.2 Procedures 52 3.2.1 Corrosion Rate: Tafel Extrapolation and Polarization Resistance Methods 53 3.2.2 Electrochemical Impedance Spectroscopy 54 4 Results and Discussion 55 4.1 Intersection Method Versus Polarization Method 55 4.2 Electrochemical Impedance Spectroscopy (EIS) 59 5 Conclusions 60 References 61 Cold Drawn Steel Surface Analysis in Contact with Saline Solution: Analysis Using Electrochemical Atomic Force Microscopy 62 1 Introduction 62 2 Experimental 63 2.1 Material 63 2.2 Sample Preparation 63 2.3 Equipment 64 2.4 Techniques Used 65 2.4.1 Atomic Force Microscopy 65 2.4.2 Electrochemical Technique 65 3 Results and Discussion 66 3.1 Calculation of the Average Topography Depth 69 3.2 Calculus of Averaged Depth by Means of Liner Polarization and Faraday ́s Law 69 4 Conclusions 72 References 72 25 Years of Experience with Cathodic Protection of Steel in Concrete in the Netherlands 74 1 Introduction 74 2 Pioneering Phase 1987-1995 75 3 Developmental Phase 1996-2004 76 4 Maturity Phase 2005-Present 77 5 Changing External Conditions 78 6 Conclusions 79 References 79 Corrosion Induced Cracking of Reinforced Concrete 81 1 Introduction 81 2 Lattice Model 82 2.1 Mechanical Model 83 2.2 Transport Model 83 3 Analysis of Corrosion Induced Cracking 84 3.1 Application to Corrosion Products 85 3.2 Investigation of the Effect of Dynamic Viscosity on the Time to Cracking 86 3.3 Investigation of the Effect of Tortuosity on the Time to Cracking 87 4 Comparison of Numerical and Experimental Results 89 5 Conclusions and Future Work 89 References 90 Influence of Crack Width on Long Term Degradation of Concrete Structures 91 1 Introduction 91 2 Experimental Procedure 92 2.1 Crack Formation 93 2.2 Exposure Regime 93 2.2.1 First Period 93 2.2.2 Second Period (Stage 4) 95 3 Results 95 4 Discussion 99 5 Conclusions 101 References 102 Influence of Cracking Caused by Structural Loading on Chloride-Induced Corrosion Process in Reinforced Concrete Elements: A Re... 103 1 Introduction 103 2 Factors Influencing Corrosion of Steel in Cracked Concrete 105 2.1 Methods of Inducing Structural Cracks 105 2.2 Methods of Corrosion Acceleration 107 2.3 Crack Width 108 2.4 Crack Orientation 110 2.5 Crack Propagation Status 111 2.6 Concrete Cover Depth 112 2.7 Concrete Composition (Water-Cementitious Materials Ratio, Mineral Additives) 113 3 Conclusions 114 References 116 Effect on Mechanical Properties and Chloride Penetration Resistance of Modified Hydrotalcite in Cement Mortar 118 1 Introduction 118 2 Experimental 120 2.1 Materials 120 2.2 Sample Preparation 120 3 Testing Methods 120 3.1 Mechanical Test 120 3.2 Mercury Intrusion Porosimetry 121 3.3 Rapid Chloride Migration (RCM) Test 121 4 Results and Discussion 122 4.1 The Effect of MHT on Strength Development 122 4.2 The Effect of MHT on Porosity 123 4.3 RCM Test 124 5 Conclusions 125 References 126 Effects of Nano-silica (NS) Additions on Durability of SCC Mixtures 128 1 Introduction 128 2 Materials and Methods 130 2.1 Materials and SCC Mix Design 130 2.2 Test Methods 131 2.2.1 Fresh Concrete Properties 131 2.2.2 Hardened Concrete: Durability Tests 132 Permeable (Water Accessible) Porosity 132 Penetration of Water Under Pressure 132 Pore Size Distribution and Porosity of the Paste 133 Rapid Chloride Migration Test (RCM) 133 Freeze-Thaw Resistance (Surface Scaling Test) 133 2.2.3 Microstructural Characterization and Analysis 134 3 Results and Discussion 135 3.1 Fresh Concrete Properties 135 3.2 Hardened Concrete: Durability 136 3.2.1 Permeable Porosity 136 3.2.2 Penetration of Water Under Pressure 137 3.2.3 Pore Size Distribution and Porosity of the Concrete Matrix 137 3.2.4 Rapid Chloride Migration Test (RCM) 139 3.2.5 Freeze-Thaw Resistance 140 3.3 Microstructural Analysis 141 4 Conclusions 143 References 144 The Effect of Climate Change on Freeze-Thaw Cycles in Nordic Climate 147 1 Introduction 147 1.1 Finnish Building Stock 147 1.2 Prefabricated Concrete Structures 148 1.3 Climate in Finland 149 1.4 Frost Attack on Concrete 150 1.5 Objectives 151 2 Research Material and Methods 151 2.1 Concrete Facades and Balconies Database 151 2.2 Climate Data and Projections 152 2.3 Number of Annual Freeze-Thaw Cycles 152 3 Results and Discussion 153 3.1 Frost Resistance of Concrete 153 3.2 Frost Damage of Concrete 154 4 Conclusions 155 References 156 Influence of Environmental Conditions on Pore Structure Change in Mortar with Various Types of Cement 157 1 Introduction 157 2 Experimental Program 158 2.1 Materials and Specimens 159 2.2 Drying/Wetting Conditions 159 2.3 Experimental Method 159 3 Results and Discussion 160 3.1 Pore Size Distribution 160 3.2 Relationship Between Pore Structure Change and Drying Condition 162 4 Deriving the Prediction Equation of Pore Structure Change 164 5 Conclusions 168 References 169 Study on the Chloride Diffusion Coefficient in Concrete Obtained in Electrically Accelerated Tests 170 1 Introduction 170 2 Traditional and Extended Chloride Transport Models 171 3 Experimental Data 172 4 Analysis of the Chloride Diffusion Coefficient 173 5 Conclusions 179 References 179 Towards Structural Modelling of Alkali-Silica Reaction in Concrete 180 1 Introduction 180 2 Experimental Observations 181 2.1 ASR Mechanism 181 2.2 Swelling of the Concrete Due to ASR Gel Expansion 182 2.3 Anisotropic Behaviour 183 2.4 Mechanical Degradation 184 3 Modeling ASR in Concrete 185 4 PAT-ASR Project: Structural Modeling 186 References 188 Free Expansion Tests for ASR at the Level of a Single Aggregate-Matrix Interface: Experimental Results and Numerical Modelling 190 1 Introduction 190 2 Numerical Model for ASR 191 2.1 Reaction Mechanism and Chemical Reactions 191 2.2 Formulation 192 3 ASR Free Expansion Tests at the Level of a Single Aggregate-Matrix Interface 192 3.1 Test Setup 192 3.2 ASR Products at the Glass-HCP Interface After Test 193 3.3 Expansion Curves 195 4 Concluding Remarks 195 References 196 Front Matter....Pages i-vi Visualisation of the Electrical Resistivity Distribution of Reinforced Concrete....Pages 1-10 Electronic and Electrolytic Conduction of Cement Pastes with Additions of Carbonaceous Materials....Pages 11-25 Influence of Anolyte on Lithium Migration in Concrete....Pages 27-34 Durability of Hydrophobic Treatments on Concrete....Pages 35-43 Steel Corrosion Rate Measurements in FA Concrete Using Three Electrochemical Techniques....Pages 45-56 Cold Drawn Steel Surface Analysis in Contact with Saline Solution: Analysis Using Electrochemical Atomic Force Microscopy....Pages 57-68 25 Years of Experience with Cathodic Protection of Steel in Concrete in the Netherlands....Pages 69-75 Corrosion Induced Cracking of Reinforced Concrete....Pages 77-86 Influence of Crack Width on Long Term Degradation of Concrete Structures....Pages 87-98 Influence of Cracking Caused by Structural Loading on Chloride-Induced Corrosion Process in Reinforced Concrete Elements: A Review....Pages 99-113 Effect on Mechanical Properties and Chloride Penetration Resistance of Modified Hydrotalcite in Cement Mortar....Pages 115-124 Effects of Nano-silica (NS) Additions on Durability of SCC Mixtures....Pages 125-143 The Effect of Climate Change on Freeze-Thaw Cycles in Nordic Climate....Pages 145-154 Influence of Environmental Conditions on Pore Structure Change in Mortar with Various Types of Cement....Pages 155-167 Study on the Chloride Diffusion Coefficient in Concrete Obtained in Electrically Accelerated Tests....Pages 169-178 Towards Structural Modelling of Alkali-Silica Reaction in Concrete....Pages 179-188 Free Expansion Tests for ASR at the Level of a Single Aggregate-Matrix Interface: Experimental Results and Numerical Modelling....Pages 189-195