Fundamentals of concrete

Contents
Chapter 1
Why concrete? 1
Chapter 2
Sustainable concrete 7
2.1 What is sustainability? 7
2.2 Life-cycle assessment 10
2.3 CO2 emissions from concrete
2.3.1 Cement 11
2.3.2 Cement extenders 12
2.3.3 Aggregates 13
2.3.4 Admixtures 13
2.3.5 Water 13
2.3.6 Concrete 14
2.4 Concrete’s contribution to a sustainable environment 16
2.5 Conclusion 17
Chapter 3
Cementitious materials 19
3.1 Manufacture and composition 20
3.1.1 Portland cement 20
3.1.2 Ground granulated blastfurnace slag (GGBS) 23
3.1.3 Fly Ash (FA) 23
3.1.4 Condensed silica fume (CSF) 23
3.1.5 Limestone 24
3.1.6 Hydration 24
3.1.7 Setting and hardening of cement paste 26
3.1.8 Curing 27
3.2 Specifications and test methods 27
3.2.1 Common cements 27
3.2.2 Masonry cements 30
3.2.3 Cement extenders 31
3.3 Properties and uses 34
3.3.1 Cements for concrete 34
3.3.2 Cements for mortars and plasters 35
3.4 Production, storage and handling 35
3.4.1 Bagged cement 35
3.4.2 Bulk cement 37
3.5 Water: cement ratio (W/C) 37
Chapter 4
Aggregates 39
4.1 Essential aggregate properties 39
4.2 Characterising aggregates 40
4.2.1 Grading 40
4.2.2 Bulk density 43
4.2.3 Particle relative density (RD) 44
4.2.4 Particle shape 44
4.2.5 Surface texture 44
4.2.6 Strength 46
4.2.7 Shrinkage 46
4.2.8 Rock types and geological formations 46
4.2.9 Alkali-silica reactivity 48
4.3 Influence of aggregate properties on the properties of concrete 48
4.3.1 How aggregate properties influence the properties of
fresh concrete 48
4.3.2 How aggregate properties affect the engineering properties of
hardened concrete 51
4.4 Aggregate derived from alternative sources 52
Chapter 5
Mixing water 55
5.1 Effects of impurities in mixing water 55
5.1.1 General 55
5.1.2 Chlorides 56
5.1.3 Sulphates 56
5.1.4 Alkali carbonates and bicarbonates 56
5.1.5 Oil 56
5.1.6 Sugar 56
5.1.7 Algae 57
5.2 Practical guidelines 57
5.3 Concrete industry wash water 58
Chapter 6
Chemical admixtures 59
6.1 Using admixtures 59
6.2 Admixtures types 60
6.2.1 Dispersing admixtures 60
6.2.2 Air-entraining admixtures 62
6.2.3 Accelerating admixtures 63
6.2.4 Retarding admixtures 64
6.2.5 Water-resisting admixtures (waterproofing) 64
6.2.6 Mortar admixtures 65
6.2.7 Admixtures for foamed concrete 65
6.2.8 Corrosion inhibitors 65
6.2.9 Anti-washout admixtures 65
6.3 Safety 65
Chapter 7
Properties of fresh concrete 67
7.1 Consistence 67
7.2 Workability 70
7.3 Settlement and bleeding 73
7.3.1 Effects 73
7.3.2 Factors that influence severity 75
7.3.3 Controlling settlement and bleeding 75
7.3.4 Overcoming harmful effects 75
7.4 Plastic shrinkage 75
7.5 Slump loss 77
7.6 Water requirement 77
7.7 Special consistence tests 79
7.7.1 Vebe test 79
7.7.2 Flow test 80
Chapter 8
Strength of hardened concrete 83
8.1 Methods of measuring strength 83
8.1.1 Compressive strength 83
8.1.2 Tensile strength 86
8.2 The relationship between compressive and tensile strength 87
8.3 Factors which influence the strength of concrete 87
8.3.1 The nature of concrete 88
8.3.2 Intrinsic factors 89
8.3.3 Extrinsic factors 91
Chapter 9
Deformation of hardened concrete 97
9.1 Practical implications of deformations 98
9.1.1 Load-related deformation 98
9.1.2 Drying shrinkage 99
9.2 Theoretical aspects 101
9.2.1 Elastic deformation 102
9.2.2 Creep 104
9.2.3 Drying shrinkage 107
Chapter 10
Durability 115
10.1 Modern durability design and specification philosophy 116
10.2 Factors affecting concrete durability 117
10.3 Concrete properties influencing durability 119
10.3.1 Transport properties 119
10.3.2 Mechanical and physical properties 120
10.3.3 Chemical properties 120
10.4 Mechanisms of deterioration 120
10.4.1 Mechanical and physical processes affecting durability 121
10.4.2 Chemical factors and processes affecting durability 122
10.4.3 Steel corrosion in reinforced concrete 123
10.5 Performance-based durability testing, design and specification
in South Africa 127
10.5.1 Durability index tests 128
Chapter 11
Concrete mix proportioning 133
11.1 Nominal proportions 133
11.2 Tables of trial mixes 134
11.3 “Eye-ball” mix design 136
11.4 The C&CI design method 137
11.4.1 Applying the method 138
11.4.2 Short-cut method of doing trial mixes 144
Chapter 12
Formwork 147
12.1 Requirements of formwork 148
12.2 Types of formwork 149
12.2.1 Permanent formwork 149
12.2.2 Temporary formwork 149
12.3 Formwork release agents 150
12.3.1 Properties and uses 150
12.3.2 Types 150
12.3.3 Application 152
12.4 Striking of formwork 152
12.5 Care of formwork 152
12.6 Safety measures 153
12.7 Falsework 154
12.8 Construction joints 155
12.8.1 Purpose 155
12.8.2 Positioning 155
12.8.3 Surface preparation 156
Chapter 13
Reinforcement 157
13.1 How reinforcement is used 158
1.1.1 Bending 158
13.1.2 Shear 158
13.1.3 Compression 159
13.2 Types of reinforcement 159
13.2.1 Plain round mild-steel bars 160
13.2.3 High-yield stress deformed bars 160
13.2.4 Fabric reinforcement 160
13.3 Bond to concrete 161
13.4 Protection of reinforcement in concrete 161
13.5 Reinforcement in practice 162
13.5.1 Working drawings 162
13.5.2 Bar bending schedules 164
13.5.3 Cutting, bending and labelling reinforcement 164
13.6 Storage of reinforcement on site 167
13.7 Fixing of reinforcement 167
13.7.1 Tying reinforcement 167
13.7.2 Reinforcement support 168
13.7.3 Splicing reinforcement 169
13.8 Checking 170
Chapter 14
Manufacture and handling of concrete 171
14.1 Production of concrete 172
14.1.1 Receiving and storing materials on site 173
14.1.2 Batching materials for concrete 175
14.1.3 Mixing concrete 178
14.1.4 Using ready-mixed concrete 181
14.2 Transporting concrete 184
14.2.1 Selecting the method of transporting 185
14.2.2 Methods of transporting concrete 185
14.3 Placing of concrete 187
14.3.1 Placing concrete under water 187
14.4 Compacting concrete 188
14.4.1 Methods of compacting 189
14.4.2 Revibration 191
14.5 Finishing concrete floors 191
14.5.1 Scheduling the work 192
14.5.2 Power floating 192
14.5.3 Power trowelling 193
14.6 Protection and curing 194
14.6.1 Protection 194
14.6.2 Curing 194
14.7 Concreting in cold weather 195
14.7.1 Cement type 196
14.7.2 Protection and curing 196
14.8 Concreting in hot weather 197
Chapter 15
Quality control and statistics for concrete 201
15.1 Sampling, testing and acceptance criteria 201
15.1.1 Sampling 201
15.1.2 Testing 202
15.1.3 Acceptance criteria 202
15.2 Process control 203
15.2.1 Target average strength 203
15.2.2 Presentation of data 204
15.2.3 Statistical assessment of results 208
15.3 Basic statistical principles 209
Chapter 16
Sand-cement mixes 215
16.1 Important properties 215
16.1.1 Workability 215
16.1.2 Water requirement 216
16.2 Yield of sand-cement mixes 218
16.3 Bedding mortars for walling 219
16.3.1 Choice of materials, mix proportions and specifications 219
16.3.2 Good practice and minimising defects 222
16.3.3 Quantities and ordering materials 223
16.4 Plaster 225
16.4.1 Requirements 225
16.4.2 Selecting materials 226
16.4.3 Mix proportions 230
16.4.4 Important properties and techniques of preparing of substrates 230
16.4.5 Preparation of specific types of substrate 233
16.4.6 Application 234
16.4.7 Troubleshooting 236
16.5 Floor screeds 238
16.5.1 Suitability and specification 238
16.5.2 Types of sand-cement screeds 242
16.5.3 Bonded screeds 242
16.5.4 Monolithic screeds 244
16.5.5 Sand-cement screeds in general 244
16.5.6 Inspecting and testing screeds 250
16.5.7 Common problems 251
Chapter 17
Appearance of concrete 253
17.1 Colour 253
17.1.1 As-cast surfaces 254
17.1.2 Colour of exposed-aggregate surfaces 257
17.2 Texture 259
17.2.1 As-cast surfaces 259
17.2.2 Unformed surface finishes 260
17.2.3 Exposed-aggregate surfaces treated in the hardened state 260
17.3 Time-related changes in appearance 263
17.3.1 Colour 263
17.3.2 Texture 264
Chapter 18
Special concretes 265
18.1 High-strength concrete 265
18.1.1 Definition 265
18.1.2 Constituent materials and mix parameters 266
18.1.3 Manufacture, placing and curing 266
18.1.4 Properties 267
18.2 High-density concrete 267
18.2.1 Definition and application 267
18.2.2 Composition 267
18.2.3 Manufacture, placing and curing 268
18.2.4 Properties 268
18.3 Low-density concrete 268
18.3.1 Definition and application 268
18.3.2 Composition and types 268
18.3.3 Manufacture, placing and curing 269
18.3.4 Properties 269
18.4 Self-compacting concrete 270
18.4.1 Definition and application 270
18.4.2 Composition 270
18.4.3 Manufacture, placing and curing 272
18.4.4 Properties 273
18.5 Fibre-reinforced concrete 273
18.5.1 Definition and application 273
18.5.2 Composition 273
18.5.3 Manufacture, placing and curing 273
18.5.4 Properties 273
18.6 Shotcrete 274
18.6.1 Definition and application 274
18.6.2 Composition 275
18.6.3 Properties 276
18.7 Roller-compacted concrete 276
18.7.1 Definition and application 276
18.7.2 Properties 276
18.7.3 RCC for dams 276
18.7.4 RCC for pavements 277
18.8 No-fines concrete 277
18.8.1 Definition and application 277
18.8.2 Composition 278
18.8.3 Manufacture 279
18.8.4 Properties 279
Glossary 283
Subject index 289