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EFFECTS OF REDISET ADDITIVE ON THE
ENGINEERING PROPERTIES OF WARM ASPHALT
BINDERS AND MIXTURES
By
BABAK GOLCHIN
Thesis submitted in fulfillment of the requirements
for the degree of
Doctor of Philosophy
February 2015
ii
1 ACKNOWLEDGEMENTS
First of all, I wish to thank Allah. Without His help and grace, I would not have
finished my research work.
I would like to express my sincere and deepest thanks to my supervisor,
Professor Meor Othman Hamzah for his valuable guidance, great advice, endless
support and kind motivation during my study. My appreciation also goes to my co-
supervisors Dr. Tye Ching Thian and Professor Madya Ahmad Shukri Yahya for
their guidance and suggestions that helped me to complete this thesis.
My thanks also go to the technicians of Highway Engineering Laboratory, Mr.
Mohd Fouzi Ali and Mr. Zulhariri Ariffin for their guidance and cooperation during
my research work in the laboratory.
I would like to express my gratitude to my friends and colleagues, Yousef
Moradi, Seyed Reza Omranian, Mohammed Rafiq Khan Kakar, Ali Jamshidi and
Mohd Rosli Hassan who had helped me with their suggestions.
My final thanks go to my lovely family who has always stood beside me.
Without their prayers, support, and encouragement, I would never have been able to
finish my dissertation. I owe them more than I could ever repay. I love them more
than everything that exists in this world.
iii
2 TABLE OF CONTENTS
ACKNOWLEDGEMENTS………………………………………………. ii
TABLE OF CONTENTS………………………………………………… iii
LIST OF TABLES………………………………………………………... x
LIST OF FIGURES………………………………………………………. xv
LIST OF PLATES………………………………………………………... xxv
LIST OF ABBREVIATIONS…………..……………………………….. xxvi
LIST OF SYMBOLS……………………………………………………... xxix
ABSTRAK………………………………………………………………... xxxii
ABSTRACT……………………………………………………………..... xxxiv
CHAPTER 1 - INTRODUCTION
1.1 General……………………………………………………………. 1
1.2 Problem Statement………………………………………………... 2
1.3 Objectives………………………………………………………… 5
1.4 Scope of Work…………………………………………………..... 5
1.5 Significance of the Research……………………………………… 7
1.6 Thesis Organization….…………………………………………… 9
CHAPTER 2 - LITERATURE REVIEW
2.1 Introduction…………………………………………………...…... 11
2.2 Rediset……………………………………………………..…...… 12
2.3 Mechanism of Temperature Reduction…………………………… 17
2.4 Asphalt Binder Properties……………………………………….... 21
iv
2.4.1 Construction Temperatures………………………………. 21
2.4.2 High Temperatures…………………………………………. 24
2.4.3 Intermediate Temperatures…………………………………. 29
2.4.4 Low Temperatures………………………………………….. 30
2.4.5 Classical Properties…………………………………………. 31
2.4.6 Storage Stability…………………………………………….. 32
2.4.7 Physicochemical Properties………………………………… 32
2.5 Asphalt Mixture Properties in Laboratory Studies…………………. 35
2.5.1 Resistance to Permanent Deformation……………………… 35
2.5.2 Resistance to Fatigue……………………………………….. 37
2.5.3 Resistance to Thermal Cracking……………………….…… 39
2.5.4 Resistance to Moisture Damage……………………….…… 39
2.5.5 Stiffness Properties…………………………………………. 44
2.5.6 Mix Design…………………………………………………. 46
2.5.7 Volumetric Properties………………………………………. 47
2.5.8 Workability and Compactability……………………………. 47
2.6 Asphalt Mixture Properties in Field Studies………………………... 50
2.6.1 United States, Georgia……………………………………… 50
2.6.2 United States, Texas………………………………………... 52
2.6.3 United States, California…………………………………… 52
2.6.4 United States, New Jersey………………………………….. 53
2.6.5 United States, Macon.………………………………………. 54
2.6.6 South Africa…………...…………………………………..... 54
2.7 Asphalt Mortar Properties…………………………………………... 55
2.8 Environmental and Economic Evaluation……………………...…... 55
2.8.1 Environmental Evaluation…………………………..……… 55
v
2.8.2 Economic Evaluation………………………………...……... 57
2.9 Summary……………………………………………………………. 58
CHAPTER 3 - METHODOLOGY
3.1 Introduction…………………………………………………………. 59
3.2 Materials……………………………………………………………. 59
3.2.1 Asphalt Binders…………………………………………….. 59
3.2.2 Aggregate…………………………………………………… 59
3.2.3 Additive…………………………………………………….. 61
3.3 Experimental Phases………………………………………………. 61
3.3.1 First Phase…………………………………………………. 61
3.3.2 Second Phase………………………………………………. 62
3.3.3 Third Phase………………………………………………... 62
3.3.4 Fourth Phase………………………………………………. 62
3.4 Rheological Properties of Asphalt Binders…………………………. 63
3.4.1 Experiment Designs………………………………………… 63
3.4.2 Sample Preparation and Aging Procedures………………… 68
3.4.3 Test Procedures……………………………………………... 69
3.4.4 Method of Analysis…………………………………………. 70
3.5 High Temperature Properties of Asphalt Binders…………………... 72
3.5.1 Sample Preparation and Experimental Design…………….. 73
3.5.2 Test Procedures……………………………………………... 74
3.5.2.1 Temperature Sweep Test…………………………… 75
3.5.2.2 Strain Sweep Test………………………………...… 75
3.5.2.3 Frequency Sweep Test……………………………… 75
3.5.2.4 Superpave High Failure Temperature Properties….... 75
vi
3.5.2.5 Flow Test…………………………………………… 76
3.5.2.6 Multiple Stress Creep and Recovery Test…………... 76
3.5.2.7 Creep Test…………………………………………... 78
3.5.2.8 Stress Sweep Test…………………………………... 79
3.5.2.9 Zero Shear Viscosity Test…………………………... 80
3.6 Mix Design and Optimization……………………………………… 81
3.6.1 Experimental Design………………………………………. 83
3.6.2 Sample Preparation and Laboratory Tests………………….. 86
3.6.3 Analysis Method……………………………………………. 88
3.6.3.1 Determination of the OBC of WMA……………….. 88
3.6.3.2 Optimization in Production Process of WMA……… 88
3.7 Combined Effects of Aging and Moisture Conditioning…………… 94
3.7.1 Experimental Design………………………………………. 95
3.7.2 Sample Preparation…………………………………………. 97
3.7.3 Sample Conditioning……………………………………….. 98
3.7.4 Testing Procedures…………………………………………. 100
3.7.4.1 Indirect Tensile Strength…………………………… 100
3.7.4.2 Resilient Modulus……………………..…………… 102
3.7.4.3 Dynamic Creep Test………...……………………… 103
3.7.5 Analysis of Test Results……………………………………. 104
3.8 Summary……………………………………………………………. 105
CHAPTER 4 - RHEOLOGY OF AGED AND UNAGED BINDERS
4.1 Introduction…………………………………………………………. 107
4.2 One-Factor-At-A-Time Method……………………………………. 107
4.2.1 Rotational Viscosity………………………………………… 107
vii
4.2.1.1 Unaged Binders…………………………………….. 107
4.2.1.2 Short-Term Aged Binders………………………….. 111
4.2.1.3 Non-Dimensional Viscosity Index…………………. 114
4.2.1.4 Activation Energy………………………...………… 116
4.2.2 Rutting Resistance………………………………………..… 117
4.2.2.1 Unaged State………………………………………... 117
4.2.2.2 Short-Term Aged State……………………………... 120
4.2.2.3 Non-Dimensional Superpave Rutting Parameter..….. 124
4.2.3 Fatigue Resistance………………………………………….. 127
4.3 Response Surface Method………………………………………….. 131
4.3.1 Rotational Viscosity………………………………………… 131
4.3.2 G*/Sin δ…………………………………………………….. 138
4.3.3 G*Sin δ …………………………………………………….. 142
4.4 Summary……………………………………………………………. 145
CHAPTER 5 - HIGH TEMPERATURE RHEOLOGICAL
………………. PROPERTIES OF BINDERS
5.1 Introduction…………………………………………………………. 147
5.2 Oscillatory Tests……………………………………………………. 147
5.2.1 Temperature Sweep Test…………………………………… 147
5.2.2 Frequency Sweep Test……………………………………… 149
5.2.3 Strain Sweep Test…………………………………………... 153
5.2.4 High Failure Temperature……………...…………………… 155
5.3 Non-Oscillatory Tests…………………………………….………… 156
5.3.1 Flow Test…………………………………………………… 156
5.3.2 Creep Test…………………………………………………... 160
viii
5.3.3 Stress Sweep Test…………………………………………... 164
5.3.4 Zero Shear Viscosity Test…………………………………... 167
5.4 Multiple Stress Creep and Recovery Test…………………………... 168
5.5 Summary……………………………………………………………. 174
CHAPTER 6 - MIX DESIGN AND OPTIMIZATION
6.1 Introduction………………………………………………………..... 176
6.2 Volumetric Properties……………………………………………..... 176
6.3 Strength Properties………………………………………………….. 185
6.4 Energy Savings……………………………………………………... 190
6.5 Effects of Raw Materials Prices…………………………………….. 192
6.6 Optimum Binder Content…………………………………………… 194
6.7 Optimization in Production Process of WMA……………………… 197
6.8 Summary……………………………………………………………. 203
CHAPTER 7 - MOISTURE CONDITIONING AND AGING
7.1 Introduction………………………………………………………... 204
7.2 Effects of Moisture Conditioning Methods and Aging……………. 205
7.2.1 Resilient Modulus…………………………………………. 205
7.2.2 Indirect Tensile Strength…………………………………... 205
7.3 Effects of Rediset Content and Compaction Temperature………… 209
7.3.1 Resilient Modulus…………………………………………. 209
7.3.2 Indirect Tensile Strength……………………………...…… 212
7.3.3 Dynamic Creep…………………………………………….. 216
7.4 Combined Aging and Moisture Conditioning of WMA Samples…. 220
7.4.1 Resilient Modulus…………………………………………. 220
ix
7.4.2 Indirect Tensile Strength……………………...…………… 223
7.4.3 Dynamic Creep………………………………………..…… 229
7.5 Stiffness Ratio………….……………………………………..…… 232
7.6 Summary…………………………………………………………... 234
CHAPTER 8 - CONCLUSIONS AND RECOMMENDATIONS
8.1 Conclusions………………………………………………………... 235
8.2 Recommendations for Future Works……………………………… 239
REFERENCES
APPENDIX A ASPHALT BINDER
APPENDIX B ASPHALT MIXTURE
x
3 LIST OF TABLES
Table 2.1 Recommended Dosage of Rediset WMX and Its Effects
on the Production Temperature of WMA
14
Table 2.2 Recommended Dosage of Rediset WMX by AkzoNobel
(AkzoNobel, 2013)
14
Table 2.3 Physical and Chemical Properties of Rediset WMX
15
Table 2.4 Methods for Preparing Rediset-Modified Asphalt Binder
16
Table 2.5 Surfactant in Asphalt Binders and Mixtures Researches
20
Table 2.6 Amount of Change in Properties of Asphalt Binders Due
to Addition of Rediset
28
Table 2.7 Effects of Rediset on the Properties of Asphalt Binders
at Low Temperatures
31
Table 2.8 Field Studies Using Rediset (Estakhri et al., 2010; Tsai
and Lai, 2010; Jenkins et al., 2011; Jones et al., 2011b;
Willis et al., 2011; Bennert, 2012b)
50
Table 2.9 Laboratory Tests for Collected Samples from Asphalt
Plant and Test Sections in Georgia, United States (Tsai
and Lai, 2010)
51
Table 2.10 Laboratory Test Results for the Field Samples after One
Year in Service in Texas, United States (Estakhri et al.,
2010)
52
Table 2.11 Test Results in New Jersey, United States (Bennert,
2012b)
53
Table 2.12 Statistical Difference Between Control Samples and
Mortars Containing Rediset (Arega et al., 2013)
55
xi
Table 3.1 Properties of Asphalt Binders
60
Table 3.2 Aggregate Gradation for AC14 Wearing Course
60
Table 3.3 Engineering Properties of Granite Aggregate Used
61
Table 3.4 Experiment Matrix for Rotational Viscosity
66
Table 3.5 Experiment Matrix for G*/sin δ
67
Table 3.6 Experiment Matrix for G*sin δ
68
Table 3.7 Use of RSM in Some Applied Sciences
72
Table 3.8 Parameter of Stress Sweep Test
80
Table 3.9 Recommended Parameters for Creep Tests to Determine
the ZSV
81
Table 3.10 Experimental Matrix for Determining OBC and
Optimization Process
84
Table 3.11 Responses and Their Acceptable Range (JKR, 2008)
85
Table 3.12 Selected Conditions for Determining the OBC
89
Table 3.13 Selected Goals and Criteria for Numerical Optimization
in the Production Process of WMA
93
Table 3.14 Cycles of Aging and Moisture Conditioning
96
Table 3.15 Test Parameters and Test Outputs for Multiple Aging
and Moisture Conditioning
96
Table 3.16 Parameters for Resilient Modulus Test
103
xii
Table 3.17 Test Parameters for Dynamic Creep Test
103
Table 4.1 Statistical Analysis of Viscosity of Unaged PG64 Binder
110
Table 4.2 Statistical Analysis of Viscosity of Unaged PG76 Binder
110
Table 4.3 Statistical Analysis of Viscosity of PG64 Binder (Short-
Term Aging)
112
Table 4.4 Statistical Analysis of Viscosity of PG76 Binder (Short-
Term Aging)
113
Table 4.5 Statistical Analysis of Rutting Parameter for Unaged
PG64 Binder
119
Table 4.6 Statistical Analysis of Rutting Parameter for Unaged
PG76 Binder
120
Table 4.7 Statistical Analysis of Rutting Parameter for PG64
Binder Subjected to Short-Term Aging
122
Table 4.8 Statistical Analysis of Rutting Parameter for PG76
Binder Subjected to Short-Term Aging
122
Table 4.9 Statistical Analysis of Fatigue Parameter of PG64
Binder Subjected to Long-Term Aging
129
Table 4.10 Statistical Analysis of Fatigue Parameter of PG76 binder
Subjected to Long-Term Aging
129
Table 4.11 Rotational Viscosity Based on the Experiment Design
for PG64 and PG76 Binders
131
Table 4.12 Models Proposed for Prediction of Viscosity,
Ln(G*/sinδ) and G*sin δ
133
Table 4.13 Analysis of Variance for Viscosity, G*/sin δ and G*sinδ 134
xiii
Table 4.14 G*/sin δ Based on Experiment Design for PG64 and
PG76 Binder
139
Table 4.15 G*sin δ Based on Experiment Design for PG64 and
PG76 Binders
143
Table 5.1 High Failure Temperature of Warm Asphalt Binders
155
Table 5.2 Stress Sensitivity of Asphalt Binders
173
Table 6.1 Models Proposed for Volumetric and Strength
Properties of PG64-WMA
178
Table 6.2 Models Proposed for Volumetric and Strength
Properties of PG76-WMA
179
Table 6.3 ANOVA for Air Voids, Gmb and VFA (PG64-WMA)
180
Table 6.4 ANOVA for Air Voids, Gmb and VFA (PG76-WMA)
181
Table 6.5 ANOVA for Strength Properties of PG64-WMA
186
Table 6.6 ANOVA for Strength Properties of PG76-WMA
186
Table 6.7 The Use of Energy for Producing 1 Ton of WMA
191
Table 6.8 Parameters for Determining the Energy Consumption
191
Table 6.9 Price for Raw Materials in February 2013
193
Table 6.10 Total Price of Raw Materials for Production of 1 Ton
WMA in February 2013
193
Table 6.11 OBC for Defined Conditions
196
Table 6.12 Optimum Point in Production Process of WMA 198
xiv
Table 6.13 Verification of Optimum Point
199
Table 6.14 Effects of Rediset Price on the Production Process of
PG64-WMA
200
Table 6.15 Outputs of Optimization Process for Three Ambient
Temperatures (PG64-WMA)
201
Table 6.16 Effects of Different Goals on the Selection of Optimum
Conditions for WMA
202
Table 7.1 Description of Cycles 0, 1, 2, and 3 in Multiple Aging
and Moisture Conditioning
222
Table 7.2 Stiffness Ratio for Different Cycles of Conditioning
233
xv
4 LIST OF FIGURES
Figure 2.1 Flow Chart of Literature Review
12
Figure 2.2 Curves of TG and DTG for Asphalt Binder Containing
Rediset (van de Ven et al., 2012)
34
Figure 3.1 One-factor-at-a-time Experimental Designs for
Rheological Evaluation of Asphalt Binders Containing
Rediset
64
Figure 3.2 Flowchart for Evaluation of High Service Temperature
Properties of Asphalt Binders Containing Rediset
73
Figure 3.3 Schematic Forms of Oscillatory Tests Using DSR
74
Figure 3.4 Schematic Forms of Non Oscillatory Tests Using DSR
74
Figure 3.5 A schematic Forms of the Results of Multiple Stress
Creep and Recovery Test
77
Figure 3.6 Experimental Plan for Determining OBC and
Optimization Process
84
Figure 3.7 Alternative Form for Demonstrating the Experiment
Design for PG64 Asphalt Mixture Based on the Central
Composite Design
86
Figure 3.8 Typical Forms of Desirability Functions
90
Figure 3.9 Effects of Aging and Moisture Conditioning on
Stiffness Properties of Asphalt Mixtures (Kim, 2009)
94
Figure 3.10 Experimental Design for Evaluating the Effects of
Aging and Moisture Conditioning on the Properties of
WMA
95
xvi
Figure 3.11 Test Outputs for Aging and Moisture Conditioning
97
Figure 3.12 Curve of Load Versus Deformation for Demonstrating
the Fracture Energy (Xiao et al., 2013c)
101
Figure 4.1 Relationship Between Viscosity and Temperature for
PG64 Binder
108
Figure 4.2 Relationship Between Viscosity and Temperature for
PG76 Binder
109
Figure 4.3 Relationship Between Viscosity and Temperature for
Binders Containing 1% Rediset
110
Figure 4.4 Rotational Viscosity of Base Binder and RTFO-Aged
Binders (PG64)
111
Figure 4.5 Rotational Viscosity of Base Binder and RTFO-Aged
Binders (PG76)
112
Figure 4.6 Relative Change in Viscosity of PG64 Binder
Containing Rediset Due to Aging
113
Figure 4.7 Relative Change in Viscosity of PG76 Binder
Containing Rediset Due to Aging
114
Figure 4.8 Temperature Versus Non-Dimensional Viscosity Index
( S ) of Unaged Binders
115
Figure 4.9 Temperature Versus Non-Dimensional Viscosity Index
( S ) of Unaged Binders
116
Figure 4.10 Activation Energy of Unaged Binders
117
Figure 4.11 Activation Energy of Binders Subjected to Short-Term 117
xvii
Aging
Figure 4.12 G*/sin δ of Unaged PG64 Binders Containing Various
Rediset Contents Versus Temperature
118
Figure 4.13 G*/sin δ of Unaged PG76 Binders Containing Various
Rediset Contents Versus Temperature
119
Figure 4.14 Relationship Between G*/sin δ and Temperature for
PG64 Binder Subjected to Short-Term Aging
120
Figure 4.15 Relationship Between G*/sin δ and Temperature for
PG76 Binders Subjected to Short-Term Aging
121
Figure 4.16 Aging Index Versus Temperature for PG64 Binders
Containing Rediset
123
Figure 4.17 Aging Index Versus Temperature for PG76 Binders
Containing Rediset
123
Figure 4.18 NSRP for Rediset-Modified Unaged PG64 Binder
125
Figure 4.19 NSRP for Rediset-Modified PG64 Binder Subjected to
Short-Term Aging
126
Figure 4.20 NSRP for Rediset-Modified Unaged PG76 Binder
126
Figure 4.21 NSRP for Rediset-Modified PG76 Binder Subjected to
Short-Term Aging
127
Figure 4.22 Relationship Between G*sin δ and Temperature for
PG64 Binder Containing Rediset Subjected to Long-
Term Aging
128
Figure 4.23 Relationship Between G*sin δ and Temperature for
PG76 Binder Containing Rediset Subjected to Long-
Term Aging
128
xviii
Figure 4.24 Relationship Between RG and Temperature for
Rediset-Modified PG64 Binder
130
Figure 4.25 Relationship Between RG and Temperature for
Rediset-Modified PG76 Binder
130
Figure 4.26 Predicted Versus Actual Viscosity
136
Figure 4.27 Plot of Response Surface for the Viscosity of Unaged
Binders
137
Figure 4.28 Interaction Effects of Rediset with Temperature and
Aging Condition on the Viscosity of PG64 Binder
138
Figure 4.29 Predicted and Actual Values of Ln(G*/sin δ)
140
Figure 4.30 Plot of Response Surface for Ln(G*/sin δ) of Unaged
Binders
141
Figure 4.31 Interaction Effects of Rediset with Temperature and
Binder Type on Ln(G*/sin δ) for Selected Conditions
142
Figure 4.32 Predicted Versus Actual Values of G*sin δ
144
Figure 4.33 Plot of Response Surface for G*sin δ of Binders
Subjected to Long-Term Aging
145
Figure 4.34 Interaction Effect of Rediset with Temperature on
G*sin δ for PG64 Binder
145
Figure 5.1 G* and Phase Angle Versus Test Temperatures for
PG64 Binder
148
Figure 5.2 G* and Phase Angle Versus Test Temperatures for
PG76 Binder
149
Figure 5.3 Relationship Between G’ and G” and Frequency of
Loading for PG64 Binder
151
xix
Figure 5.4 Relationship Between G’ and G” and Frequency of
Loading for PG76 Binder
151
Figure 5.5 Relationship Between Viscosity and Frequency of
Loading
152
Figure 5.6 G* and Phase Angle Versus Frequency of Loading
153
Figure 5.7 Relationship Between G* and Shear Strain
154
Figure 5.8 Phase Angle Versus Shear Strain
154
Figure 5.9 Relationship Between Rediset Content and High
Failure Temperature
156
Figure 5.10 Viscosity Versus Shear Rates for PG64 Binder
Incorporating Rediset
158
Figure 5.11 Viscosity Versus Shear Rates for PG76 Binder
Incorporating Rediset
158
Figure 5.12 Relationship Between Stress and Shear Rate for
Binders Containing Rediset
159
Figure 5.13 Relationship Between Strain and Time for PG64
Binders Subjected to Creep Loads
161
Figure 5.14 Relationship Between Strain and Time for PG76
Binders Subjected to Creep Loads
162
Figure 5.15 Creep Compliance Versus Time for PG64 Binder under
10 Pa Creep Load
163
Figure 5.16 Creep Compliance Versus Time for PG76 Binder under
10 Pa Creep Load
163
xx
Figure 5.17 Viscosity Versus Stress for PG64 Binder Containing
Rediset at Stress Sweep Test
165
Figure 5.18 Viscosity Versus Stress for PG76 Binder Containing
Rediset at Stress Sweep Test
165
Figure 5.19 Viscosity Versus Shear rate for PG64 Binder
Containing Rediset at Stress Sweep Test
166
Figure 5.20 Viscosity Versus Shear rate for PG76 Binder
Containing Rediset at Stress Sweep Test
166
Figure 5.21 Relationship Between ZSV and Rediset Content for
PG64 Binder
167
Figure 5.22 Relationship Between ZSV and Rediset Content for
PG76 Binder
167
Figure 5.23 Jnr Versus Rediset Content under Various Stress Loads
168
Figure 5.24 Cumulative Shear Strain Versus Time of Loading for
PG64 Binder, 100 Pa
170
Figure 5.25 Cumulative Shear Strain Versus Time of Loading for
PG64 Binder, 3200 Pa
170
Figure 5.26 Cumulative Shear Strain Versus Time of Loading for
PG76 Binder, 100 Pa
171
Figure 5.27 Cumulative Shear Strain Versus Time of Loading for
PG76 Binder, 3200 Pa
171
Figure 5.28 Relationship Between Average Percentage of Recovery
and Rediset Content
172
Figure 5.29 Stress Sensitivity Versus Rediset Content for PG64 173
xxi
Binder
Figure 5.30 Stress Sensitivity Versus Rediset Content for PG76
Binder
174
Figure 6.1 Volumetric Properties of PG64-WMA
183
Figure 6.2 Volumetric Properties of PG76-WMA
184
Figure 6.3 Strength Properties of PG64-WMA
187
Figure 6.4 Strength Properties of PG76-WMA
188
Figure 6.5 Relationship Between G*/sinδ of Short-term Aged
PG64 Binder and Rediset Content
189
Figure 6.6 Relationship Between G*/sinδ of Short-term Aged
PG76 Binder and Rediset Content
189
Figure 6.7 Energy Consumption for Production of 1 Ton WMA
192
Figure 6.8 Total Price of Raw Materials for Production of 1 Ton
WMA
194
Figure 6.9 Response Surface of Overall Desirability Function for
Different Binder Content, Rediset Content, and
Compaction Temperature
199
Figure 7.1 Effects of Aging and Moisture Conditioning on the
Resilient Modulus of PG64 Mixtures
206
Figure 7.2 Effects of Aging and Moisture Conditioning on the
Resilient Modulus of PG76 Mixtures
207
Figure 7.3 Effects of Aging and Moisture Conditioning on the ITS
of PG64 Mixtures
207
xxii
Figure 7.4 Effects of Aging and Moisture Conditioning on the ITS
of PG76 Mixtures
208
Figure 7.5 Relationship Between Resilient Modulus and ITS for
Various Aging and Moisture Conditioning
208
Figure 7.6 Relationship Between Resilient Modulus and Rediset
Content (PG64)
210
Figure 7.7 Relationship Between Resilient Modulus and Rediset
Content (PG76)
211
Figure 7.8 ITS Versus Rediset Content for Various Compaction
and Test Temperatures
213
Figure 7.9 Fluctuation of the Flow Versus Rediset Content at
25°C
214
Figure 7.10 Fluctuation of the Fracture Energy Versus Rediset
Content at 25°C
214
Figure 7.11 Effects of Compaction and Test Temperatures on the
Flow
215
Figure 7.12 Fracture Energy Versus Rediset Content for Various
Test Temperatures and Binder Types
216
Figure 7.13 Cumulative Micro Strain Versus Dynamic Creep
Cycles at 40°C
218
Figure 7.14 Cumulative Micro Strain Versus Dynamic Creep
Cycles at 60°C
219
Figure 7.15 Schematic Form of the Creep Performance
220
Figure 7.16 Combined Effects of Aging and Moisture Conditioning
on the Resilient Modulus of PG64 Mixtures
221
xxiii
Figure 7.17 Combined Effects of Aging and Moisture Conditioning
on the Resilient Modulus of PG76 Mixtures
221
Figure 7.18 General Trend of Resilient Modulus for Various Cycles
of Aging and Moisture Conditioning
222
Figure 7.19 Combined Effects of Aging and Moisture Conditioning
on the ITS of PG64 Mixtures
224
Figure 7.20 Combined Effects of Aging and Moisture Conditioning
on the ITS of PG76 Mixtures
224
Figure 7.21 ITS Versus Cycles of Aging and Moisture
Conditioning
225
Figure 7.22 Combined Effects of Aging and Moisture Conditioning
on the Flow of PG64 Mixtures
226
Figure 7.23 Combined Effects of Aging and Moisture Conditioning
on the Flow of PG76 Mixtures
226
Figure 7.24 Flow Versus Cycles of Aging and Moisture
Conditioning
227
Figure 7.25 Fracture Energy Versus Cycles of Aging and Moisture
Conditioning for PG64 Mixtures
228
Figure 7.26 Fracture Energy Versus Cycles of Aging and Moisture
Conditioning for PG76 Mixtures
228
Figure 7.27 Effects of the Aging and Moisture Conditioning on
Fracture Energy
229
Figure 7.28 Relationship Between Fracture Energy and ITS
229
Figure 7.29 Cumulative Micro Strain of Conditioned and
Unconditioned PG64 Mixtures
230
Figure 7.30 Cumulative Micro Strain of Conditioned and 231
xxiv
Unconditioned PG76 Mixtures
Figure 7.31 Slope of Strain Versus Creep Loading Cycle for PG64-
W110 Mixture with 1% Rediset
232
Figure 7.32 Slope of Strain at the Last 15 Minutes of Creep Load
for Conditioned Samples
232
xxv
5 LIST OF PLATES
Plate 2.1 Rediset in Solid and Liquid Forms
13
Plate 2.2 Interaction of Rediset with a Siliceous Aggregate
(AkzoNobel, 2013)
21
Plate 3.1 RTFO and PAV
69
Plate 3.2 RV and DSR
70
Plate 3.3 Superpave Gyratory Compactor and CoreLok
87
Plate 3.4 Moisture Conditioning and Long-Term Oven Aging of
Samples
100
Plate 3.5 UTM-25 for Performing the Resilient Modulus Test
102
Plate 3.6 UTM-5 for Dynamic Creep Test 104
xxvi
6 LIST OF ABBREVIATIONS
AASHTO American Association of State Highway and
Transportation Officials
AC Asphalt Concrete
ANOVA Analysis of Variance
APA Asphalt Pavement Analyzer
ASA Anti Stripping Agent
ASTM American Society for Testing and Materials
ASCE American Society of Civil Engineers
AWD Asphalt Workability Device
BBD Box Behnken Design
BBR Bending Beam Rheometer
BBS Bitumen Bond Strength
BS British Standard
Caltrans California Department of Transportation
CCD Central Composite Design
CEI Compaction Energy Index
CEN European Committee for Standardization
CEN/TS European Committee for Standardization / Technical
Specification
DD Draft for Development
DF Degree of Freedom
DMA Dynamic Mechanical Analyzer
DOT Department of Transportation
DSR Dynamic Shear Rheometer
DSC Differential Scanning Calorimetry
DTG Derivative Thermogravimetry
DTT Direct Tensile Test
ER Energy Ratio
EN European Standard
FTIR Fourier Transform Infrared Spectroscopy
xxvii
GHG Green House Gas Emissions
HMA Hot Mix Asphalt
HVS Heavy Vehicle Simulator
HW High Natural Wax
HWT Hamburg Wheel Tracking Test
ITS Indirect Tensile Strength
JKR Jabatan Kerja Raya
LCA Life Cycle Assessment
MEPDG Mechanistic Empirical Design Guide
MI Modification Index
MR Malaysian Ringgit
MSCR Multiple Stress Creep and Recovery Test
NDIR Non Dispersive Infrared Detector
NSRP Non Dimensional Superpave Rutting Parameter
OBC Optimum Binder Content
OCD Orthogonal Composite Design
PAV Pressure Aging Vessel
PG Performance Grade
PI Penetration Index
PPE Personal Protective Equipment
PWD Public Works Department
RPM Revolution per Minute
RAP Reclaimed Asphalt Pavement
RG Relative G*sin δ
RSM Response Surface Method
RTFO Rolling Thin Film Oven
RV Rotational Viscometer
SBS Styrene Butadiene Styrene
SFE Surface Free Energy
SMA Stone Matrix Asphalt
SPT Simple Performance Tester
ST Stiffness Ratio
xxviii
Superpave Superior Performing Asphalt Pavement
TDI Traffic Densification Index
TG Thermo Gravimetric
TSR Indirect Tensile Stress Ratio
TSRST Tensile Stress Restrained Specimen Test
UCPRC University of California Pavement Research Center
USA United States of America
USM Universiti Sains Malaysia
UTM Universal Testing Machine
VFA Void in Aggregate Filled with Asphalt Binder
VG Viscosity Grade
VOC Volatile Organic Compounds
WMA Warm Mix Asphalt
ZSV Zero Shear Viscosity
xxix
7 LIST OF SYMBOLS
S Amount of Normalized Viscosity per Unit Percent of
WMA Additive
d Average Diameter of Specimen
h Average Height of Specimen
Average Percent Recovery at Stress Level of L for Total
10 Cycle
Average Viscosity over the Last 15 Min
Gmb Bulk Specific Gravity
J Creep Compliance
Creep Compliance at the End of the Test
Creep Compliance at the 15 Minutes before End
ξ Damage Parameter
G* Dynamic Modulus
η* Dynamic Viscosity
Ā Effective Cross-Sectional Area in Damaged State
Ea Energy of Activation
ER Energy Ratio
F Failure Load
Fitted Value of the Response
[G*/sin (δ)]R G*/Sin δ of Asphalt Binders Incorporating Additive
[G*/sin (δ)]c G*/Sin δ of Control Asphalt Binder without Additive
PGx-Hy HMA Fabricated Using PGx Binder and Compacted at Y
Temperature
PGx-HyTz HMA Fabricated Using PGx Binder, Compacted at Y
Temperature and Tested at Z Temperature
ITS Indirect Tensile Strength
ITSi ITS of conditioned Samples in Cycle i
ITS0 ITS of Unaged Samples
Dj Individual Desirability Function for Response Number J
Ao Initial Area of the Undamaged Section
Last 900 Seconds
xxx
G” Loss Modulus
Maximum Actual (Experimental) Values of the Response
Gmm Maximum Specific Gravity
Minimum Actual (Experimental) Values of the Response
S Non Dimensional Viscosity Index
Jnr Non Recoverable Creep Compliance
Non Recoverable Creep Compliance at the Stress Level
of L for Cycle Number N
Non Recoverable Creep Compliance at the Stress Level
of L for Total 10 Cycles
Number of Cycle of Loading
n Number of Responses Included in the Optimization
D Overall Desirability Function (Geometric Mean of the
Individual Desirability Functions)
Percent Recovery of Each Loading Cycle at Stress Level
δ Phase Angle
Mri Resilient Modulus of Conditioned Samples in Cycle i
Mr0 Resilient Modulus of Unaged Samples
γ Shear Strain
Shear Strain at the End of Creep Loading and Recovery
for Each Cycle After 10 Second
Shear Strain at the End of Each Cycle for Shear Stress of
L
Shear Strain at the End of 1 Second Loading for Each
Cycle
σ Shear Stress
Shear Stress (100 and 3200 Pa)
G’ Storage Modulus
Stress Sensitivity
G*(sin δ) Superpave Fatigue Factor
G*/sin δ Superpave Rutting Factor
T Temperature
t Time
R Universal Gas Constant
xxxi
Variation of Creep Compliance
η Viscosity
0 Viscosity of Control Binder
Viscosity of Modified Binder
Weighting Factor of the Response
PGx-Wy WMA Fabricated Using PGx Binder and Compacted at
Y Temperature
PGx-WyTz WMA Fabricated Using PGx Binder, Compacted at Y
Temperature and Tested at Z Temperature
Wdry
Work of Adhesion in Dry Condition
Wwet
Work of Adhesion in Wet Condition
xxxii
KESAN BAHAN TAMBAH REDISET KE ATAS SIFAT KEJURUTERAAN
PENGIKAT DAN CAMPURAN ASFALT SUAM
8 ABSTRAK
Rediset adalah bahan tambah kimia yang berpotensi untuk membolehkan
campuran asphalt dihasilkan dan dipadat pada suhu yang lebih rendah berbanding
suhu penyediaan campuran turapan asphalt biasa. Tesis ini mendedahkan aspek baru
penggunaan Rediset di dalam pengikat dan campuran asfalt. Objektif utama kajian
ini adalah untuk mencirikan kesan kandungan Rediset terhadap sifat reologi pengikat
asfalt dan campuran asfalt yang didedahkan kepada pelbagai keadaan persekitaran
termasuk penuaan, suhu ujian dan keadaan kelembapan. Kesan kandungan Rediset
terhadap parameter Superpave dikaji menggunakan kaedah reka bentuk eksperimen
satu faktor pada satu masa dan kaedah tindak-balas permukaan. Manakala, kesan
kandungan Rediset terhadap sifat reologi bahan pengikat pada suhu tinggi diuji
menggunakan reometer ricih dinamik berasaskan pelbagai ujian makmal yang
meliputi suhu, terikan, frekuensi, pelbagai tegasan, aliran, rayapan, rayapan pelbagai
tegasan dan pemulihan, serta kelikatan ricih sifar. Penetapan kandungan bahan
pengikat optimum (OBC) Rediset dan suhu pemadatan. Kaedah pengoptimaan baru
dicadangkan untuk penentuan kandungan Rediset, kandungan bahan pengikat dan
suhu pemadatan yang bersesuaian. Gabungan kesan pengusiaan dan kelembapan
keatas sifat ketegaran campuran asphalt bersuhu sederhana (WMA) dikaji
mengunakan ujian modulus kenyal, kekuatan tegangan tak-langsung dan rayapan
dinamik. Keputusan ujikaji menunjukkan Rediset menurunkan kelikatan bahan
pengikat semasa ujian dijalankan pada suhu tinggi dan meningkatkan ketahanan
xxxiii
bahan turapan terhadap keretakan sebagai akibat kelesuan pada suhu pertengahan.
Pencampuran Rediset didapati tidak mengubah gred prestasi semua bahan pengikat
yang diuji. Di samping itu, menerusi ujian pelbagai aliran dan tegasan, kandungan
Rediset yang tinggi meningkatkan kelikatan bahan pengikat terpinda.
Walaubagaimanapun, kaedah tindak-balas permukaan (RSM) menunjukkan
pengunaan Rediset di dalam campuran bahan turapan bersuhu sederhana tidak
mengubah kandungan bahan pengikat optimum yang diperlukan oleh campuran
bahan turapan panas (HMA) yang lazim digunakan di Malaysia. Pengunaan Rediset
pada kadar yang tinggi menurunkan sedikit kestabilan dan ketegaran campuran
asphalt bersuhu suam. Berdasarkan hasil kajian terperinci, kandungan Rediset
sebanyak 1% dicadangkan dan kandungan ini bersesuaian untuk pelbagai keadaan
bagi mengoptimumkan pengeluaran campuran asphalt jenis ini. Gabungan kesan
pengusiaan dan kelembapan bertindak secara bertentangan dengan sifat ketegaran
bahan turapan bersuhu suam. Proses penuaan meningkatkan kekuatan tegangan
tidak-langsung dan modulus kebingkasan campuran asfalt, manakala kelembapan
telah menurunkan kedua-dua nilai tersebut.
xxxiv
EFFECTS OF REDISET ADDITIVE ON THE ENGINEERING
PROPERTIES OF WARM ASPHALT BINDERS AND MIXTURES
9 ABSTRACT
Rediset is a chemical warm additive that has potentials to reduce the
compaction and mixing temperatures of asphalt mixtures. This thesis covers new
aspects on the use of Rediset in warm asphalt binders and mixtures. The main
objective of this study is to characterize the effects of Rediset contents on the
rheological properties of asphalt binders and asphalt mixtures subjected to various
environmental conditions including aging, test temperature, and moisture
conditioning. The effects of Rediset content on Superpave parameters were
investigated using one-factor-at-a-time experimental design and response surface
method. The effects of Rediset content on high temperature rheological properties of
binders were evaluated using the dynamic shear rheometer based on temperature,
strain, frequency and stress sweep, flow, creep, multiple stress creep and recovery
and zero shear viscosity tests. The optimum binder content (OBC) of warm mix
asphalt (WMA) was studied for mixtures prepared with various Rediset contents and
compaction temperatures. A new optimization procedure was proposed to select the
appropriate Rediset content, binder content and compaction temperature. The
combined effects of aging and moisture conditioning on the stiffness properties of
WMA were studied using resilient modulus, indirect tensile strength and dynamic
creep tests. The test results showed that Rediset decreased the viscosity of binders at
very high temperatures and improved the Superpave fatigue resistance at
intermediate temperatures. The incorporation of Rediset did not change the
xxxv
performance grade of all binders tested. In the flow and stress sweep test, higher
Rediset content resulted in higher viscosity for modified binders. The OBC results
using RSM indicated that the OBC of WMA containing Rediset is similar to the
OBC of typical hot mix asphalt (HMA). Using higher Rediset content slightly
decreased the stability and stiffness of WMA. The optimization process in the
production of WMA proposed 1% Rediset content as the optimum additive content
for various scenarios. The combined effects of aging and moisture conditioning on
stiffness properties of WMA indicated that aging and moisture conditioning had
opposing effects on the stiffness properties of WMA. The aging process increased
the indirect tensile strength (ITS) and resilient modulus of the asphalt mixtures,
while the moisture conditioning reduced these values.
xxxvi
1
1 CHAPTER 1
INTRODUCTION
1.1 General
Warm mix asphalt (WMA) additives are materials which can be used to reduce
the mixing and compaction temperatures of asphalt mixtures. The use of such
materials can decrease both fuel consumption and emissions from asphalt plants and
hence can be considered as an environmentally sustainable technology. Therefore,
WMA technology can be important to policy makers, decision makers, asphalt
suppliers and researchers.
Using WMA additives permits longer haul distances, provides more time for
compaction of asphalt mixtures, permits operation of asphalt plants in regions with
strict air pollution rules, extends the pavement construction season, improves the
workability of asphalt mixtures at lower compaction temperatures, improves the
aggregate coating by asphalt binders, slows binder aging, reduces wear and tear on
asphalt mixture facilities, reduces odor emissions from asphalt plants, and improves
working conditions at paving sites (Bennert et al., 2010; Hamzah et al., 2010a; Arega
et al., 2011; Kim et al., 2011a; Banerjee et al., 2012; Xiao et al., 2012b).
WMA additives are classified into three groups: chemical additives, foamed
asphalt binder technology, and organic additives (Rubio et al., 2012; Capitão et al.,
2012). Rediset is a water-free chemical warm additive that can reduce compaction
and mixing temperatures of asphalt mixtures by about 35°C (Arega et al., 2011;
Banerjee et al., 2012). It is a combination of surfactants and organic additives into
2
which the surfactants can improve the aggregate surfaces wetting potential with
binder by active adhesion and the other components that reduces binder viscosity
(Prowell et al., 2007). This thesis will cover new aspects of the use of Rediset in
WMA studies.
1.2 Problem Statement
According to the detailed literature review conducted on the performance of
WMA and especially WMA incorporating Rediset, some specific issues and
problems were identified.
Most of researchers are interested to compare the rheological properties of the
effects of the manufacturer’s recommended dosage of WMA additives with each
other. Bennert et al. (2010), Arega et al. (2011), Xiao et al. (2011a), Benerje et al.
(2012), and Xiao et al. (2012b) compared the effects of fixed dosage of Rediset in
comparison with those of binders containing Sasobit, Evotherm, and Cecabese. Since
strain tolerance of asphalt binders are significantly varied depending on asphalt
binder sources and aging conditions (Kim, 2009), it is postulated that the
recommended dosage of Rediset by the manufacturer might be inappropriate for the
modification of asphalt binders under selected aging conditions. Therefore, it is
necessary to evaluate the effects of Rediset content on the various rheological
properties of asphalt binders subjected to different aging conditions.
Previous researchers such as Arega et al. (2011) and Xiao et al. (2012b) have
only investigated the main effects of WMA additives on the rheological properties of
asphalt binders without the quantification of the effects of the additive content and
3
its interaction with other factors such as aging conditions, test temperatures, and
binder types. Therefore, the quantification of the effects of Rediset on the rheological
properties of asphalt binders using mathematical relationships can be a useful
approach to provide a clear interpretation in characterizing the asphalt binder
properties.
The rheological properties of asphalt binders play an important role on the
performance of asphalt mixtures at high temperatures. WMA are more prone to
permanent deformation at high temperature conditions (Capitão et al., 2012).
Therefore, characterization of high service temperature properties of asphalt binders
containing various Rediset contents under various shear loads can provide useful
information in prediction of the real performance of WMA.
In mix design methods, the optimum binder content (OBC) for each material
and each preparation method is determined by developing a distinct volumetric and
strength behavior model. It is obvious that determining the OBC for a range of
materials and methods, in aforementioned procedure, needs a lot of time and
materials. The use of experimental design methods based on response surface
method (RSM) has ability to decrease the number of samples required for testing and
provide a possibility to determine the OBC for selected conditions. From the review
of the literatures, it seems that the evaluation of warm mix asphalt behavior
incorporating Rediset using RSM can be a new approach for determining the OBC of
WMA.
4
In asphalt mixture performance studies, most researchers investigated the effects of
compaction and mixing temperatures of WMA as well as other test parameters like
binder type, aggregate source, and aggregate gradation using one-factor-at-a-time
procedure (Hurley and Prowell, 2005; Bennert et al., 2010; Bennert et al., 2011; Mo
et al., 2012). In this approach, the effects of these parameters cannot be
simultaneously analyzed. Consequently, determining the optimum mixing and
compaction temperatures and even binder and additive contents are difficult.
Therefore, it is necessary to reach a procedure to optimize production process of
warm mix asphalt in terms of mixing or compaction temperature, additive content
and binder content, simultaneously. To meet this objective, using regional standard
specifications, minimization of the cost of raw materials in production of WMA, and
minimization of energy consumption are necessary and important.
Evaluation of the moisture damage of asphalt mixtures in field condition shows
that pavement usually gains strength for a short time because of aging and then
begins to weaken because of stripping (Kim, 2009). WMA are susceptible to
moisture damage (Capitão et al., 2012). Although, some limited aspects of the
combined effects of aging and moisture conditioning for asphalt mixtures and
asphalt binders were studied (Lu and Harvey, 2006; Copeland et al., 2007; Grenfell
et al., 2012; Punith et al., 2012), this phenomenon is needed to be studied for WMA
incorporating Rediset, as well.
5
1.3 Objectives
This research was conducted to characterize the effects of Rediset on asphalt
binder and asphalt mixture properties based on the problems stated in Section 1.2.
The detailed objectives are as follows:
i. To investigate the rheological properties of asphalt binders containing various
Rediset content subjected to different aging conditions and test temperatures
using one-factor-at-a-time method and response surface method.
ii. To evaluate the high temperature rheological properties of asphalt binders
incorporating Rediset under different shear loading conditions.
iii. To study the effects of binder content, compaction temperature, Rediset
content on the engineering properties of WMA and subsequently determining
the optimum binder contents using response surface method and proposing an
optimization method for production process of WMA.
iv. To assess the combined effects of aging and moisture conditioning on the
properties of WMA containing Rediset measured in terms of indirect tensile
strength, dynamic creep and resilient modulus properties.
1.4 Scope of Work
The scope of work is limited to a study on the effects of various Rediset
contents on the properties of asphalt binders and mixtures. The aggregate type used
was crushed granite aggregate based on Malaysian Public Works Department (JKR)
gradation for mix type AC14. Since, PG64 asphalt binder is a conventional asphalt
binder in construction of the roads in Malaysia and PG76 asphalt binder is a polymer
modified binder that has ability to improve the performance of conventional asphalt
6
binders, these binders were selected for fabrication of asphalt mixtures. Asphalt
mixtures were mixed and compacted at three temperatures using a gyratory
compactor. The asphalt binders were characterized using a rotational viscometer
(RV) and a dynamic shear rheometer (DSR), while the properties of asphalt mixtures
were analyzed based on the results of volumetric measurements, Marshall test and
also using the resilient modulus, dynamic creep and indirect tensile strength tests.
This research was carried out in the following four phases:
In the first phase, Superpave performance tests were conducted on the asphalt
binders containing Rediset under unaged, short-term aged, and long-term aged
conditions at very high, high, and intermediate temperatures. Short- term aging and
long-term aging was performed by rolling thin film oven (RTFO) and pressure aging
vessel (PAV) according to ASTM D2872 (ASTM, 2006a) and ASTM
D6521(ASTM, 2006b), respectively.
The second phase focused on strain sweep, stress sweep, frequency sweep,
temperature sweep, flow, creep, multiple stress creep recovery, and zero shear
viscosity tests for binders incorporating Rediset at high performance temperatures.
Phase three covered the determination of the OBC of WMA using Marshall
tests and volumetric measurements based on central composite experimental design
and response surface method. This phase also used the JKR standard specification,
cost of raw materials in the production of WMA and energy consumption for
determining the optimum mixing temperature, Rediset content and binder content.
7
In phase four, three aging cycles and two moisture conditioning cycles were
used as a combined conditioning process for evaluating the effects of aging and
moisture conditioning on the stiffness properties of WMA. Aging was done at a high
temperature (85°C) for 3 days while moisture conditioning was conducted by
vacuuming the samples in water for 30 minutes, freezing the samples and
submerging the same samples in water for 24 hours at 60°C (in chemical
environment).
1.5 Significance of the Research
This research evaluates the performance of WMA containing Rediset for
Malaysian local materials including asphalt binders, aggregate type, and aggregate
gradation. So, the outcomes of this research can promote rational use of this product
in the local context.
Rediset decreases fuel consumption and emissions from asphalt plants and can
be a green sustainable technology. So, the detailed knowledge from the results of this
research can be useful to policy and decision makers to select the appropriate
alternatives for a sustainable development.
Although the lower production and paving temperatures of WMA are
beneficial, there are other problems associated with its usage. The incomplete drying
of the aggregates, poor bitumen coating, less aging of the binder and moisture
susceptibility can lead to poor performance (Rubio et al., 2012). Recently, limited
rheological properties of some asphalt binders and mixtures containing Rediset have
been investigated in comparison with other WMA additives like Sasobit and
8
Cecabase. Rediset is a combination of the wax and surfactant, while Sasobit and
Cecabase are wax and surfactant warm additives, respectively (Prowell et al., 2007;
Chowdhury and Button, 2008; Smiljanic et al., 2009; Tsai and Lai, 2010; Zaumanis
and Haritonovs, 2010; Bennert, 2012b; Kheradmand et al., 2014; Shi et al., 2013;
Zhu et al., 2013; Jamshidi et al., 2013). Therefore, it is necessary to characterize the
effects of Rediset content on the engineering properties of asphalt binders and
mixtures. The results of this study can provide useful information for future works to
upgrade and develop a native warm additive to suit Malaysian conditions.
Test procedures in engineering and scientific experiments are often guided by
subjective consideration of practicality and established laboratory protocols (Mason
et al., 2003). While these kinds of experiments are viewed economically based on the
number of test runs, statistical approaches in design of experiments are used to
ensure that experiments are designed by economical criteria (Mason et al., 2003).
Introducing and developing methods for finding some basic parameters using
statistical experimental design (objective 3 and some part of objective 1), will
decrease the use of materials and laboratory efforts.
This study presents a new approach for determining the optimum binder
content in warm mix asphalts based on the volumetric and strength behavior of
asphalt mixture samples using a specific experimental design (response surface
method). Also, developing an optimization procedure in the production process of
WMA to reach an optimum mixing temperature, binder content and Rediset content
can be important step in building a decision making system for WMA technologists.
These ideas will open a new horizon for asphalt material researchers and warm mix
9
additive producers as well as civil engineers in the design and evaluation of asphaltic
materials.
In last part of this thesis, the combined effects of aging and moisture damage
on the stiffness properties of WMA were characterized. These results can provide an
initial informative data for prediction of the behavior of WMA incorporating Rediset
in the laboratory conditions.
1.6 Thesis Organization
This thesis is divided into eight chapters and presented as follows:
i. Chapter One introduces WMA and explains the problem statement,
objectives, significance of the research, and scope of study.
ii. Chapter Two describes previous studies on the effects of Rediset on the
rheological properties of asphalt binders and asphalt mixtures. The effects of
Rediset in field studies are shown in this chapter, as well.
iii. Chapter Three explains the materials, sample preparation methods, tests
procedures, and data analysis methods for characterization of the asphalt
binders and mixtures.
iv. Chapter Four presents the results of the evaluation of the effects of Rediset
content on the rheological properties of asphalt binders subjected to various
aging conditions and test temperatures.
v. Chapter Five shows the results of shear loads on the high service
temperatures properties of asphalt binders incorporating Rediset tested using
the DSR machine.
10
vi. Chapter Six deliberates on the results, discussions, and statistical analysis on
the effects of Rediset content, mixing temperature, and binder content on
asphalt mixture properties to determine the OBCs and to develop an
optimization method in production process of WMA using response surface
method.
vii. The combined effects of aging and moisture conditioning on the stiffness
properties of asphalt mixtures incorporating Rediset are presented and
discussed in chapter Seven.
viii. Chapter Eight presents the conclusions and recommendations for future
works.
Chapters Four and Five cover the first and second objectives of the research,
while Chapters Six and Seven cover objectives three and four, respectively.
11
2 CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
This chapter collected, summarized and discussed the effects of Rediset on the
rheological properties of asphalt binders, laboratory performance of asphalt
mixtures, field behavior of constructed road sections, energy consumption, air
pollution, physicochemical properties of asphalt binders, and behavior of asphalt
mortars based on the studies reported in journal papers, technical reports, theses, and
conference proceedings. The rheological effects of Rediset were scrutinized in four
aspects: i. very high temperature properties in terms of viscosity of asphalt binder
and workability of asphalt mixtures, ii. high temperature properties in terms of
rutting resistance of asphalt mixtures and binders, iii. intermediate temperature in
terms of fatigue performance, and iv. low temperature cracking properties. The new
detailed information reported in graphs, tables, and texts of available scientific
literatures related to Rediset were checked, summarized, and discussed. Other topics
such as the mechanism of performance of Rediset, moisture susceptibility, mix
design issues, volumetric properties, storage stability, and some economic aspects
were investigated, as well. Figure 2.1 shows the structure of this literature review
chapter.
12
Figure 2.1: Flow Chart of Literature Review
2.2 Rediset
In 2007, Rediset was introduced in the United States (Bonaquist, 2011) to
reduce some deficiencies of existing WMA additives (Hainin et al., 2013). Rediset is
currently marketed as a warm mix additive with adhesion promoting properties
(Bonaquist, 2011). It is a chemical (water-free) WMA additive from AkzoNobel,
Netherlands (Arega et al., 2011), Sweden (Smiljanić et al., 2009; Syroezhko et al.,
2011; Mo et al., 2012), and United States (Isebäck, 2012). In solid form, it is
described by the name of Rediset WMX, while in liquid form, it is described by the
name of Rediset LQ (AkzoNobel, 2013). Plate 2.1 shows the typical solid and liquid
forms of Rediset.
Field performance Laboratory performance:
Rutting, fatigue, thermal
cracking, workability,
mix design, stiffness,
moisture damage,
volumetric properties
Future works
Effects of Rediset on
asphalt mixture
Conclusions
Environmental and
economical effect
Effects of Rediset on
asphalt binders
Effects of Rediset on
asphalt mortar
Mechanism of Performance of Rediset
Introduction
Performance at
very high, high,
intermediate and low
temperatures
13
Plate 2.1: Rediset in Solid and Liquid Forms
In scientific literatures, different percentages of Rediset WMX were reported
for modification of asphalt binders. Table 2.1 summarized the recommended dosages
of Rediset WMX and its predicted effects on the temperature reduction. From Table
2.1, it can be seen that 1 to 3% of Rediset WMX contents were used for modification
of WMA to provide a temperature reduction between 17°C and 35°C. Table 2.2
gives useful information regarding the use of Rediset WMX (AkzoNobel, 2013).
According to Leng et al. (2013), Rediset LQ reduces mixing and paving
temperatures of WMA by 15°C to 30°C. This additive is added at the rate of 0.5 to
1% into the asphalt binder (Leng et al., 2013). Since, there is a limited study on the
effects of Rediset LQ on the performance of asphalt binder and mixtures, this
literature survey will cover the effects of Rediset WMX for use in WMA and
generally referred to as Rediset.
Rediset LQ Rediset WMX
14
Table 2.1: Recommended Dosage of Rediset WMX and Its Effects on the
Construction Temperature of WMA
No. Recommended
dosage
Reduction in construction
temperatures References
1 1.5% - (Xiao et al., 2012b)
2 1.5-2% 35°C (Arega et al., 2011)
3 1-2% 54°F (30 ºC) (Tsai and Lai, 2010)
4 2% - (Arega and Bhasin, 2012)
5 - 20-30ºC (Smiljanić et al., 2009)
6 1-3% 20-35°C (Trujillo, 2011)
7 1.5-2.5% - (Bonaquist, 2011)
8 1.25-2% - (Vallabhu, 2012)
9 - 35°C (Banerjee et al., 2012)
10 1-3% - (Sengoz et al., 2013)
11 2% 60°F (33ºC) (Sampath, 2010)
12 - 17-28°C (Frequently observed)
>28 (Observed) (Al-Qadi et al., 2012b)
13 1.5-2% 60°F (33ºC) (Chowdhury and Button,
2008)
Table 2.2: Recommended Dosage of Rediset WMX by AkzoNobel (AkzoNobel,
2013)
Selected conditions Rediset (%)
Compaction aid 0.5-1.0
WMA for conventional binder
(30°C reduction) 1.0-1.5
WMA for polymer modified binder and stone
mastic asphalt (SMA) (30°C reduction) 1.5-2
Improving the workability and for hand-laid
mixtures 2-3
15
Rediset is a poly functional additive based on fatty amine surfactants and oly
ethylenes (Smiljanic et al., 2011). According to Xiao et al. (2011b) and Xiao et al.
(2012a), Rediset is a combination of fatty polyamines, polymer, and non-ionic
components. This additive contains a long chain aliphatic hydrocarbon structure and
an –NH3+ group which chemically reacts with aggregate surfaces (Syroezhko et al.,
2011). According to Smiljanic et al. (2009), chemical structure of Rediset is based on
the alkildiamine and hydrocarbon waxes. Table 3.2 shows some chemical and
physical properties of Rediset.
Table 2.3: Physical and Chemical Properties of Rediset WMX
Properties Value/description References
Physical state Solid
(Xiao et al. 2011b; Xiao et
al. 2012a; Xiao et al.
2012b)
Color Brown
Odor Amine like
Solubility in water Insoluble in cold water
Bulk density 0.55 g/cc
(AkzoNobel, 2013) Bulk density 4.6 lbs./gal
Flash point >150°C
Melting point 85°C (Arega and Bhasin, 2012)
Melting point 80-90°C (Trujillo, 2011)
Rediset dissolves easily in hot asphalt binder without the need for a high
shear mixer device (Trujillo, 2011). According to Arega and Bhasin (2012), this
additive melts at about 85°C and completely blends with the asphalt binder (Arega
and Bhasin, 2012). Although, conventional mixing temperatures of hot mix asphalt
are proposed by suppliers for blending the warm additives with the asphalt binder
16
(Arega et al., 2011), in laboratory studies, various mixing temperatures and different
mixing methods as well as various times of blending were used for preparing
Rediset-modified asphalt binder as shown in Table 2.4.
Table 2.4: Methods for Preparing Rediset-Modified Asphalt Binder
No.
Number
of binder
type
Type of mixer Blending
temperature
Blending
duration
Rediset
content Reference
1 8
Medium-shear
radial flow
impeller at 300
rpm
Hot binder 5 minutes 1.5 (Xiao et al.,
2012b)
2 4
Digital overhead
mixer equipped
with a four-Blade
propeller
30
minutes 2%
(Arega et al.,
2011)
3 1 Low shear mixer 196°C 1 hour 1 and
2%
(Bennert et
al., 2010)
4 1 Low shear mixer 196°C 1 hour 1 and
2%
(Bennert et
al., 2011)
5 8
Medium-shear
radial flow
impeller at 300
rpm
5 minutes 1.5% (Xiao et al.,
2013b)
6 2
Digital overhead
mixer equipped
with a four blade
propeller
30 minuts 2% (Arega et al.,
2013)
7 1 Mechanical stirrer
at 6000 rpm 150°C
10
minutes
(Abdullah et
al., 2012)
8 1 High shear mixer
at 2000 rpm 150-160°C
10
minutes
1, 2, 3,
and 4%
(Hainin et
al., 2013)
9 1 High shear mixer
at 2000-2500 rpm
120 to
130ºC
10
minutes 1, 2%
(van de Ven
et al., 2012)
10 1 - 155 to 160ºC 30
minutes 3%
(Syroezhko
et al., 2011)
11 1 High shear mixer 10
minutes 1.5%
(Doyle et al.,
2013)
12 2 Low shear mixer 149°C 2% (Alavi et al.,
2012)
17
Rediset can be added into the asphalt binder or can be added into the mixture
during the mixing procedure (Chowdhury and Button, 2008; van de Ven et al.,
2012). If this additive is directly blended with asphalt binder at the refinery, the
existing asphalt plant does not need any modifications (Chowdhury and Button,
2008). According to Bonquist (2011), Rediset can be added into the asphalt binder in
the asphalt plant supply tank or into the mixture in the asphalt plant drum.
Rediset is a patented additive that differs from other chemical additives (like
Evotherm and Cecabase) because it can act like an anti stripping agent and can
improve the moisture susceptibility of the asphalt mixtures (Banerjee et al., 2012).
Rediset usually does not need other anti stripping agent for use in mixture because
this product provides anti-stripping properties (Chowdhury and Button, 2008).
The producer of this additive claims that this material performs beyond a
typical warm additive. It acts as anti striping agent, anti oxidant agent, easy
compactor additive, as well as warm mix additive (AkzoNobel, 2013).
2.3 Mechanism of Temperature Reduction
According to the scientific literatures, three mechanisms are used for reducing
the production temperature of WMA as follows (Hanz et al., 2010a):
i. Reducing the viscosity of asphalt binders by adding organic additives such as
wax (first mechanism)
ii. Foaming the asphalt binder through the use of hydrophilic additives (zeolite)
or using injected water in vaporization process (second mechanism)
18
iii. Regulating and decreasing the frictional forces at the interface of the
aggregate and asphalt binder at high temperature ranges, for instance between
85-140°C with the use of chemical additives (third mechanism) (Al-Qadi et
al., 2012a).
Rediset is a multifunctional WMA additive (van de Ven et al., 2012) that
reduces mixing and compaction temperature of WMA based on first and third
mechanisms. Rediset is a combination of the surfactant (surface active agent) and
organic additives (rheology modifier) (Prowell et al., 2007; Chowdhury and Button,
2008; Tsai and Lai, 2010; Zaumanis and Haritonovs, 2010; Bennert, 2012b;
Kheradmand et al., 2014; Shi et al., 2013; Zhu et al., 2013). The surfactant part of
this product (similar to chemical additives) decreases the surface tension of asphalt
binder (Banerjee et al., 2012; Vallabhu, 2012), reduces the interfacial frictions
between thin film of asphalt binder and aggregate (Arega and Bhasin 2012; Capitão
et al. 2012) and improves the wettability of aggregate by asphalt binder (Banerjee et
al., 2012), while the organic part reduces the viscosity of asphalt binder and provides
lubricating effect for easier coating and compaction (Tsai and Lai, 2010;
Kheradmand et al., 2014). Chemical additives are not similar to organic additives.
They act at the microscopic interface of the asphalt binders and aggregates, while the
organic additive change some asphalt binder properties such as viscosity.
Emulsification agents, surfactants, and polymers are chemical additives that improve
coating, workability, and compaction properties of asphalt mixtures (Al-Qadi et al.,
2012a).
19
Rediset promotes active and passive adhesion between aggregate and asphalt
binder (Syroezhko et al., 2011). It chemically modifies the asphalt binder to
encourage active adhesion. Active adhesion improves coating and wetting of
aggregates by binder at high temperatures (Prowell et al., 2007; Zaumanis and
Haritonovs, 2010), while passive adhesion is related to the improvement of the
asphalt binder resistance to displacement by water (Castaño et al., 2004).
Surfactants have been widely used in the asphalt industries. Surfactants are
materials that reduce surface or interfacial tension between a liquid and a solid or
between two liquids. Surfactants are used in detergents, wetting agents, emulsifiers,
foaming agents, dispersants, and anti striping agents. Table 2.5 presents the use of
some surfactants in asphalt studies. These materials are classified into four groups:
cationic, anionic, amphoteric and nonionic surfactant (Rosen and Kunjappu, 2012).
Rediset is a cationic surfactant (Prowell et al., 2007; Zaumanis and Haritonovs,
2010; Bennert, 2012b). According to Syroezhko et al. (2011), the tail of this
surfactant can be a long chain aliphatic hydrocarbon, while its head can be a –NH3+.
The head of this additive can exhibit cationic property. Plate 2.2, shows a schematic
form of this additive as well as its interaction with a siliceous aggregate. Silica atoms
can bond with cationic surfactant, while calcium ions can bond with both anionic and
cationic surfactants (Lesueur et al., 2012). Therefore, surfactants can act as a bridge
between the asphalt binder and the aggregate surface, promote adhesion, and
improve moisture susceptibility of asphalt mixtures (Capitão et al., 2012). The
surface active compounds enable coating of damp aggregate which could be
encountered with lower drying temperatures (Bennert, 2012b).
20
Table 2.5: Surfactant in Asphalt Binders and Mixtures Researches
No. Type of surfactant Function Percentage Commercial
name Reference
1 Amine surfactant Asphaltene
dispersant 0.75
(Ahmed et al.,
2012)
2 Amine surfactant Adhesive agent 0.75
3
Combination of
rheology modifier
and surfactant
WMA additive
and adhesive
agent
1.5
4 Surfactant of amino
nature
Anti-stripping
agents 0.4
(DelRio-Prat
et al., 2011)
5 Mix of surfactants Anti-stripping
agent 0.3
6 Mix of surfactants,
waxes, polymers, etc.
Anti-stripping
agent 3
7 Surfactant
phosphoric nature
Anti-stripping
agent 0.3
8
Mix of surfactant,
wax and polymers in
a prills form
Chemical
WMA additive 3
(Sanchez-
Alonso et al.,
2013)
9 Mix of surfactants in
liquid form
Chemical
WMA additive 0.3
10
surfactant of amino
nature in viscous
liquid state
Chemical
WMA additive 0.4
11 A synthetic amides in
a liquid form WMA additive -
Gemul
XT14
(Motta et al.,
2012)
12 Metal ion surfactants Anti-stripping
agent -
(Iskender et
al., 2012)
13
Surfactant used in
nano composites with
base asphalt
Dispersing
additive -
(Fang et al.,
2013)
21
Plate 2.2: Interaction of Rediset with a Siliceous Aggregate (AkzoNobel, 2013)
2.4 Asphalt Binder Properties
2.4.1 Construction Temperatures
Asphalt binder properties at a range of mixing and compaction temperatures
can be evaluated using rotational viscosity, dynamic viscosity, kinematics viscosity,
and lubricity tests. Rotational viscosity can be used to determine the flow
characteristics of asphalt binder at the hot mixing facility (Xiao et al., 2011b; Xiao et
al., 2012b). In previous warm mix asphalt studies (Akisetty et al., 2009; Lee et al.,
2009, Silva et al., 2010; Arega et al., 2011; Shang et al., 2011; Xiao et al., 2012a;
Xiao et al., 2012b), rotational viscosity has been extensively used to evaluate the
warm asphalt binder’s behavior in both unaged and short-term aged conditions.
The use of Rediset decreases the rotational viscosity of asphalt binders (Xiao et
al., 2011b; Sengoz and Oylumluoglu, 2013). It implies that lowering viscosity can be
one of the mechanisms that Rediset uses for reducing the mixing and compaction
temperatures. The degree of change of the rotational viscosity depends on the binder
type, binder source, test temperature, aging state, and Rediset content (Sampath,
22
2010; Arega et al., 2011; Xiao et al., 2011b; Mo et al., 2012; Xiao et al., 2012b).
Some researchers showed that binders with Rediset have lower viscosity than other
WMA additives like Evotherm, Cecabase, Aspha-min, and Sasoflex regardless of
test temperature and binder type (Xiao et al., 2011b; Xiao et al., 2012b). In addition,
van de Ven et al (2012) reported that the effects of Rediset on the viscosity become
less when temperature increases from 100ºC to 150ºC. In another study, Xiao et al.
(2011b) reported that the viscosity of Rediset-modified binder does not obviously
change when the storage duration increases.
Rediset has positive effects on kinematic and dynamic viscosity, as well.
According to Zaumanis and Haritonovos (2010) and Shi et al. (2013), Rediset
decreases kinematic viscosity of asphalt binder at 135°C. Also, van de Ven et al.
(2012) showed that Rediset has strong influence on the dynamic viscosity at 110°C
for a hard asphalt binder using the result of DSR with a cone and plate device.
Although the positive effects of Rediset on the viscosity has been mostly
reported, Arega et al. (2011) observed a negative effect of 2% Rediset on the
rotational viscosity for a PG76-22 asphalt binder containing high amount of natural
wax under unaged condition at 135°C. This case was not observed for the same
binder in short-term ageing condition as well as other selected asphalt binders in
both unaged and short-term aged conditions.
The results of rotational viscosity tests can be used to determine the activation
energy of asphalt binders. Activation energy can be related to the asphalt binder
thermal susceptibility. Mo et al. (2012) showed that addition of Rediset has positive
23
effects on the reduction of activation energy and thermal susceptibility of asphalt
binders. They showed that increasing Rediset content results in less susceptibility of
the material to temperature, where asphalt binders with low activation energy are
less susceptible to temperature. Equation (2.1) shows the relationship between
viscosity and activation energy based on the Arrhenius-like Equation (Mo et al.,
2012):
η =Ae(Ea/RT)
( 2.1)
where,
η = Viscosity (Pa.s)
A = Regression parameter
R = Universal gas constant (8.314 JK-1
mol-1
)
T = Temperature (°K)
Ea = Activation energy kJ/mol
In some studies, the rotational viscosity test results were used to determine
mixing and compaction temperatures of WMA using the Asphalt Institute
recommendations based on the temperature–viscosity graph. Sengoz and
Oylumluoglu (2013) showed that using Rediset decreases the mixing and
compaction temperature of WMA by 8°C and 6°C, respectively. It seems that this
method does not have the ability to predict mixing and compaction temperatures,
appropriately. Since surfactant-based WMA additives are using other types of
mechanisms for reducing mixing and compaction temperatures, other laboratory tests
such as lubricity tests were considered for evaluation of asphalt binder properties at
very high temperatures (Hanz et al., 2010b). Generally, the concepts of thin-film
24
rheology are used in lubricity test (Bennert et al., 2010). Benert et al. (2010) showed
that the shear rate of asphalt binder with various amounts of Rediset is higher than
neat binder at peak point of torque on DSR plates in lubricity test. It implies that
internal friction in the particles of asphalt mixture containing Rediset can be lower
than asphalt mixture without warm additive. Lower internal friction provides a
successful condition for production of WMA.
2.4.2 High Temperatures
According to the literatures discussed in this section, high temperature
properties of asphalt binders blended with Rediset is evaluated by different
parameters such as dynamic modulus (G*), phase angle (δ), dynamic viscosity (η*),
Superpave rutting factor (G*/sin δ), high failure temperature, high temperature
Superpave performance grade (PG), creep compliance, creep angle, and also
softening point under unaged or short-term aging condition. Some of these
parameters were determined at specific temperatures (at high performance grade
temperature or at a reference temperature such as 60°C), a range of temperatures
(temperature sweep tests), or in a specific loading condition (frequency sweep tests,
strain sweep tests, flow tests, and creep and recovery tests). These parameters can be
used to predict the resistance of asphalt mixtures to permanent deformation. The
effects of Rediset on the properties of asphalt binders at high temperature are:
i. Positive effects: Shi et al. (2013) reported that addition of 2% Rediset
increases dynamic viscosity of asphalt binders tested at 60°C by
approximately 21.8% and 38.9%. Research conducted by Doyle et al. (2013)
showed that incorporating 1.5% Rediset increases G*/sin δ of asphalt binder
