Principles of Pavement Engineering

468 Pages·2008·5.17 MB·English

by  Thom

Principles of pavement
engineering
Nick Thom
University of Nottingham
PublishedbyThomasTelfordPublishing,ThomasTelfordLtd,1HeronQuay,LondonE144JD.
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Firstpublished2008
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ISBN:978-0-7277-3480-8
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Contents
Foreword xvii
Acknowledgements xix
Part 1 Principles 1
1.1 Introduction 3
1.1.1 The long history of the paved highway, 3
1.1.2 Materials for pavement construction, 5
1.1.2.1 Soil, 5
1.1.2.2 Granular material, 5
1.1.2.3 Hydraulically-bound material, 6
1.1.2.4 Bitumen-bound material, 7
1.1.2.5 Other materials, 8
1.1.3 Typical pavement structures, 9
1.1.3.1 Pavement layers, 10
1.1.3.2 Pavement cross-sections, 11
1.1.4 Financial cost, 12
1.1.5 Sustainability and the environment, 13
1.1.5.1 Material sources, 13
1.1.5.2 The energy issue, 14
1.1.6 Summary, 15
1.2 Pavement applications 17
1.2.1 High-speed highways, 17
1.2.1.1 Ride quality, 17
1.2.1.2 Skid resistance, 18
1.2.1.3 Surface noise, 18
1.2.1.4 Low maintenance, 19
iii
1.2.1.5 Typical constructions, 20
1.2.2 Urban roads, 20
1.2.2.1 Maintenance-friendly construction, 21
1.2.2.2 High skid resistance, 22
1.2.2.3 Rut resistance, 22
1.2.2.4 Low maintenance, 23
1.2.3 Estate roads, 23
1.2.3.1 Cheap construction, 24
1.2.3.2 Passable for decades, 24
1.2.3.3 Occasional heavy traffic, 24
1.2.4 Rural roads, 25
1.2.4.1 Ride quality, 25
1.2.4.2 Skid resistance, 26
1.2.5 Pedestrian areas and cycle paths, 26
1.2.6 Car, coach and lorry parks, 27
1.2.6.1 Load-bearing capacity, 27
1.2.6.2 Surface finish, 28
1.2.7 Ports and heavy industrial pavements, 28
1.2.7.1 Uneven deformation, 29
1.2.8 Airfield pavements, 30
1.2.8.1 Limiting deformation, 31
1.2.8.2 Skid resistance, 32
1.2.8.3 Avoiding closures, 32
1.2.8.4 Fuel and oil spillage, 33
1.2.8.5 Foreign object damage (FOD), 33
1.2.9 Summary, 33
1.3 Practical issues 34
1.3.1 Unbound material, 34
1.3.1.1 Natural soils, 34
1.3.1.2 Granular materials — particle size distribution, 34
1.3.1.3 Particle soundness, 35
1.3.1.4 Particle shape, 36
1.3.1.5 Water content, 36
1.3.1.6 Placement and compaction, 38
1.3.2 Hydraulically-bound material, 38
1.3.2.1 Particle shape and size distribution, 38
1.3.2.2 Water content, 39
1.3.2.3 Mixing and batching, 40
1.3.2.4 Placement and compaction, 40
1.3.2.5 In situ stabilisation, 41
iv
1.3.2.6 Curing, 42
1.3.2.7 Reinforcement, 43
1.3.2.8 Joints, 44
1.3.2.9 Surface finish, 45
1.3.3 Asphalt, 46
1.3.3.1 Particle shape and size distribution, 46
1.3.3.2 Mixing and batching, 47
1.3.3.3 Placement and compaction, 48
1.3.3.4 Inter-layer bond, 50
1.3.3.5 Asphalt reinforcement, 50
1.3.3.6 Surface finish, 51
1.3.4 Summary, 52
1.4 Basic engineering concepts 53
1.4.1 Basic quantities, 53
1.4.1.1 Mass, 53
1.4.1.2 Weight, 53
1.4.1.3 Density, unit weight and specific gravity, 54
1.4.1.4 Force and load, 54
1.4.1.5 Stress and pressure, 54
1.4.1.6 Strain, 55
1.4.2 Mechanical properties, 55
1.4.2.1 Stiffness, 55
1.4.2.2 Elastic modulus (or elastic stiffness), 55
1.4.2.3 Stiffness modulus and resilient modulus, 56
1.4.2.4 Poisson’s ratio, shear modulus and bulk modulus, 56
1.4.2.5 Modulus of subgrade reaction, 57
1.4.2.6 Viscosity and kinematic viscosity, 59
1.4.3 Thermal properties, 59
1.4.3.1 Coefficient of thermal expansion, 59
1.4.3.2 Thermal conductivity, 60
1.4.3.3 Specific heat capacity, 60
1.5 Conclusion to Part 1 61
Notes 62
Part 2 Materials 65
2.1 Unbound material 67
2.1.1 Shear strength, 67
2.1.1.1 Inter-particle slip, 67
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2.1.1.2 Angle of internal friction, 68
2.1.1.3 Stress ratio at failure, 70
2.1.1.4 Interlock, 70
2.1.1.5 Cohesion, 71
2.1.1.6 The effect of particle and mixture properties, 72
2.1.1.7 Shear strength tests, 77
2.1.1.8 Typical shear strength values, 78
2.1.1.9 The California bearing ratio, 80
2.1.1.10 Plate loading tests, 81
2.1.1.11 Cone penetrometers, 82
2.1.2 Stiffness, 82
2.1.2.1 The mechanism of unbound material strain, 83
2.1.2.2 The resulting stress—strain behaviour, 84
2.1.2.3 The effect of differing stress conditions, 85
2.1.2.4 The effect of particle and mixture properties, 87
2.1.2.5 Stiffness tests, 91
2.1.2.6 Typical stiffness modulus values, 94
2.1.3 Deformation under repeated load, 95
2.1.3.1 The mechanism of plastic deformation, 95
2.1.3.2 Modelling plastic deformation, 95
2.1.3.3 The effect of material variables, 97
2.1.3.4 Tests for plastic strain under repeated load, 97
2.1.4 Permeability, suction, plasticity and frost, 97
2.1.4.1 The fluid mechanics of permeability, 98
2.1.4.2 Predicting permeability, 99
2.1.4.3 Flow through a graded aggregate, 100
2.1.4.4 Measuring permeability, 103
2.1.4.5 Partial saturation and suction, 103
2.1.4.6 Plasticity, 105
2.1.4.7 Frost heave and frost damage, 107
2.1.5 Summary, 108
2.2 Hydraulically-bound material 110
2.2.1 Strength, 110
2.2.1.1 Tensile strength, 111
2.2.1.2 Flexural strength, 112
2.2.1.3 Indirect tensile strength, 113
2.2.1.4 Compressive strength, 114
2.2.1.5 Strength gain with time, 115
2.2.2 Fatigue, 116
2.2.3 Durability, 118
vi
2.2.3.1 Water damage, 118
2.2.3.2 Frost damage, 119
2.2.4 Thermal properties, 120
2.2.5 Stiffness, 121
2.2.5.1 Stiffness measurement, 121
2.2.5.2 Influences on material stiffness, 122
2.2.5.3 Typical material stiffness values, 124
2.2.5.4 Relationship between stiffness and strength, 125
2.2.5.5 The effective stiffness of a discontinuous layer, 125
2.2.6 Mixture design, 127
2.2.6.1 Wet-formed mixtures, 127
2.2.6.2 Roller-compacted mixtures, 128
2.2.6.3 Typical concrete mixtures, 129
2.2.6.4 Fibre-reinforced concrete, 130
2.2.6.5 Relationship between laboratory and site, 131
2.2.6.6 Slow-curing materials, 131
2.2.6.7 In situ stabilised materials, 132
2.2.7 Summary, 134
2.3 Asphalt 136
2.3.1 Bitumen, 136
2.3.1.1 Viscosity, 136
2.3.1.2 Penetration and softening point, 137
2.3.1.3 Visco-elasticity, 138
2.3.1.4 Fracture and fatigue, 140
2.3.1.5 The bitumen-filler mortar system, 142
2.3.1.6 Bitumen chemistry, 143
2.3.1.7 Bitumen ageing, 145
2.3.1.8 Bitumen modification, 146
2.3.1.9 Bitumen emulsion, 147
2.3.2.10 Foamed bitumen, 148
2.3.2 The mechanics of asphalt behaviour, 149
2.3.2.1 The micromechanics of asphalt damage, 150
2.3.2.2 Linear or non-linear?, 151
2.3.2.3 Bitumen adhesion, 151
2.3.3 Asphalt stiffness, 152
2.3.3.1 Predicting asphalt stiffness, 153
2.3.3.2 Measuring asphalt stiffness, 153
2.3.3.3 Typical stiffness values, 154
2.3.4 Fracture and fatigue of asphalt, 156
2.3.4.1 Low-temperature fracture, 156
vii
2.3.4.2 Fatigue damage, 157
2.3.4.3 Tests for fatigue of asphalt, 157
2.3.4.4 Development of a fatigue characteristic, 159
2.3.4.5 Healing, 160
2.3.5 Permanent deformation, 160
2.3.5.1 The influence of binder, 161
2.3.5.2 Measurement of permanent deformation, 162
2.3.6 Durability, 164
2.3.6.1 Ageing, 164
2.3.6.2 Water damage, 164
2.3.6.3 Frost damage, 166
2.3.6.4 Biodegradation, 166
2.3.7 Mixture design, 166
2.3.7.1 Aggregate particle size distribution, 167
2.3.7.2 Binder content, 169
2.3.7.3 Binder grade, 171
2.3.7.4 Filler, 172
2.3.7.5 Cold mixes, 173
2.3.7.6 Grouted macadam mixes, 176
2.3.8 Summary, 178
2.4 Reinforcing products 179
2.4.1 Unbound material reinforcement, 179
2.4.1.1 Reinforcing mechanism, 179
2.4.1.2 Reinforcement effect, 180
2.4.1.3 Membranes, 181
2.4.1.4 Grids, 181
2.4.2 Hydraulically-bound material reinforcement, 182
2.4.3 Asphalt reinforcement, 183
2.4.3.1 Sealing, 183
2.4.3.2 Inhibiting cracking, 183
2.4.3.3 Reducing permanent deformation, 185
2.4.4 Summary, 185
2.5 Conclusion to Part 2 186
Notes 188
Part 3 Design 197
3.1 Design principles 199
3.1.1 Engineering principles, 200
viii
3.1.2 Whole-life cost, 200
3.1.3 Sustainability, 202
3.1.3.1 Material resource depletion, 203
3.1.3.2 Blight, 204
3.1.3.3 Energy usage, 205
3.1.3.4 Emissions, 207
3.1.3.5 Groundwater issues, 208
3.1.4 Summary, 208
3.2 Traffic loading 210
3.2.1 Traffic variables, 210
3.2.1.1 Load magnitude, 210
3.2.1.2 Contact pressure, 212
3.2.1.3 Load groups, 214
3.2.1.4 Dynamic effects, 214
3.2.1.5 Loading speed, 216
3.2.1.6 Lateral wander, 217
3.2.2 Determining design traffic, 217
3.2.3 Summary, 219
3.3 Design against rutting 220
3.3.1 Subgrade deformation, 220
3.3.1.1 The real behaviour of soils, 220
3.3.1.2 Multi-layer linear elastic analysis, 221
3.3.1.3 Calculating closeness to failure, 222
3.3.1.4 The subgrade strain criterion, 223
3.3.1.5 Dealing with water, 224
3.3.1.6 Subgrade softening, 227
3.3.1.7 Stabilised subgrades, 228
3.3.2 Deformation in granular layers, 229
3.3.2.1 The elastic analysis approach, 229
3.3.2.2 The plastic analysis approach, 230
3.3.2.3 Plastic analysis of multi-layer structures, 231
3.3.2.4 The effect of reinforcement, 232
3.3.2.5 The shakedown approach, 233
3.3.3 Deformation in asphalt, 234
3.3.3.1 Assigning a mixture viscosity, 234
3.3.3.2 Carrying out an analysis, 235
3.3.3.3 Accounting for temperature variation, 236
3.3.3.4 Other factors affecting rut development, 237
3.3.4 Summary, 238
ix
3.4 Design against cracking 239
3.4.1 Cracking of hydraulically-bound materials, 239
3.4.1.1 Pavementqualityconcrete—Westergaardanalysis,239
3.4.1.2 Pavementqualityconcrete — multi-layerlinearelastic
analysis,242
3.4.1.3 Pavement quality concrete — limit state analysis, 242
3.4.1.4 Pavement quality concrete — warping stress
analysis, 245
3.4.1.5 Pavement quality concrete — joint spacing, 248
3.4.1.6 Pavement quality concrete — joint deterioration, 249
3.4.1.7 Pavement quality concrete — joint type, 250
3.4.1.8 Reinforced concrete, 251
3.4.1.9 Continuously reinforced concrete (CRC), 253
3.4.1.10 Rapid-setting hydraulically-bound layers — thermal
stress analysis, 255
3.4.1.11 Slow-setting hydraulically-bound layers — thermal
stress analysis, 257
3.4.1.12 Stronghydraulically-boundlayers — trafficloading,257
3.4.1.13 Weak hydraulically-bound layers, 259
3.4.2 Cracking of asphalt, 260
3.4.2.1 Low-temperature cracking, 260
3.4.2.2 An overview of wheel-path cracking, 262
3.4.2.3 Design temperature, 263
3.4.2.4 Traditional analytical pavement design, 264
3.4.2.5 Pavements with a thin asphalt layer, 266
3.4.2.6 Predicting crack propagation, 267
3.4.2.7 Top-down cracking, 271
3.4.2.8 Pavement edge design, 273
3.4.2.9 Reflective cracking — thermally-induced, 273
3.4.2.10 Reflective cracking — traffic-induced, 275
3.4.2.11 Reinforced asphalt, 278
3.4.3 Summary, 279
3.5 Design for durability 281
3.5.1 The effect of time, 281
3.5.2 The effect of water, 282
3.5.2.1 Water in asphalt, 282
3.5.2.2 The effect of traffic on saturated bound material, 283
3.5.2.3 Water in joints, 285
3.5.2.4 Water in pavement foundations, 285
3.5.3 The effect of frost, 287
x