DRAFT
Summary Report of
HVS Testing of the Palmdale Test Site, North Tangent Sections:
Evaluation of Long Life Pavement Rehabilitation Strategies— Rigid
Report prepared for the California Department of Transportation by:
Louw du Plessis, Fritz Jooste, Steve Keckwick, Wynand Steyn
CSIR Transportek
PO Box 395
Pretoria, Republic of South Africa
Technical Edit: John Harvey, Bill Nokes
Pavement Research Center
Institute of Transportation Studies
University of California Berkeley
University of California Davis
August 2005
i
EXECUTIVE SUMMARY
As part of the Caltrans Long Life Pavement Rehabilitation Strategies ( LLPRS), a
concrete pavement constructed with fast setting strength hydraulic cement concrete ( FSHCC)
and Portland cement concrete ( PCC) blend was constructed on State Route 14 about 5 miles
south of Palmdale, California. The test pavement was evaluated under Heavy Vehicle Simulator
( HVS) testing beginning June 1999 and finishing December 2001. This report summarizes part
of the testing program which was undertaken on three 70- m long test sections with a 200- mm
thick FSHCC and the following design features:
• Section 7 was constructed with plain joints ( no dowels), relying on aggregate
interlock for joint load transfer, with an asphalt concrete shoulder and a normal lane
width of 3.66 m.
• Section 9 was constructed with dowels and a concrete shoulder with tie bars and a
normal lane width of 3.66 m.
• Section 11 was constructed using a widened truck lane ( 4.26 m wide) and doweled
joints with an asphalt concrete shoulder.
The most significant observations are briefly discussed subsequently.
Environmental Influences on the Behavior of the Concrete Slab
Temperature played a significant role in the behavior of the concrete slab in two ways:
1. Daily variations in slab temperatures cause the slabs to go through cycles of
expansion and contraction, which had a noticeable effect on the measured load
transfer efficiency ( LTE) at joints. During the hotter part of the day, the slabs
expanded, the joints locked up, and LTE values close to 100 percent were commonly
ii
calculated. At night when slab contraction took place, the opposite occurred: LTE
values dropped to lower than 80 percent.
2. Owing to temperature differentials ( temperature at the surface of the slab minus the
temperature at the bottom of the slab) the concrete slabs went through cycles of being
curled upwards ( at night when the top is cooler than the bottom) and being curled
downwards ( during the day when the top is warmer than the bottom). Analysis of
deflections and temperatures indicated that high deflection measurements were
associated lower surface temperatures ( and negative temperature differentials) and
vice versa. An inversely proportional relationship was observed between surface
temperature, the temperature difference between the top and the bottom of the PCC
layer, and the measured deflections.
These two effects played major roles in the behavior of the concrete under accelerated
loading. Throughout this study, the influence of the above- mentioned slab movements were
visible on the parameters used to determine the extent and degree of damage on each test. The
surface deflections measured at night were at least double those recorded during the day at the
same locations. It is obvious that deflection measurements were highly dependent on the time of
day. It is therefore very important that slab curl resulting from temperature variations should be
built into any deflection analysis on concrete pavements.
Permanent Warping Due to Differential Shrinkage
Although concrete shrinkage was limited in some cases by the inclusion of design
features ( i. e., dowels and tie bars), the observations made during this study show that slab
warping due to differential shrinkage between the upper and the lower part of the concrete layer
iii
played a significant role in the measured deflections. Deflection sensors placed just below the
concrete in the base layer close to the edge registered very small deflections, even with the
application of test loads greater than 90 kN. Deflections recorded in the base layer were typically
less than 0.2 mm, while the surface mount modules recorded deflections between 1 and 1.2 mm
for the same test. This means that less than 20 per cent of the surface deflections were passed on
to the base layer. One explanation for this observation is that, due to differential shrinkage, the
slabs were slightly curled upwards all along its longitudinal edge which created a cavity between
the bottom of the PCC layer and the base. The high deflections measured at the top were a direct
result of this loss in support from the sub- structure.
Traffic- Induced Changes in the Behavior of the Concrete Slabs
From this study it is clear that in almost all the cases, deflection variations caused by
daily and seasonal temperature changes masked the damaging effect caused by repetitive
loading. At night ( low surface temperatures), the slabs were warmer at the bottom than the top,
causing the slabs to curl upwards and slab lift- off from the base layers occurred. Nighttime
deflection measurements were high due to the loss in support from the underlying layers. During
the day, the slabs were warmer at the top than the bottom, resulting in downward curling of the
slabs and low deflections.
A significant drop in surface deflections and subsequent increase in base layer deflections
occurred after the appearance of cracks on the undoweled test sections. The cracks caused the
slabs to come into full contact with the base layer. This resulted in increased support from the
underlying layers and, therefore, an increase in base layer deflections and a subsequent reduction
in the measured surface deflections.
iv
Comparing the Performance of the Three Different Structures
Because different loading regimes for different tests were used, direct one- to- one
comparisons of all tests is not possible. The performance of the two main structural response
parameters, edge surface deflections and load transfer efficiency ( LTE) is briefly discussed
below.
Section 7, Plain Joints ( Relying on Aggregate Interlock for Joint Load Transfer), Normal Lane
Width
Edge surface deflections under the influence of a 90- kN test load were on the order of 2
to 4 mm before any cracks appeared, and dropped to approximately 1 to 2.2 mm after edge and
corner cracks appeared.
LTE values started around 99 percent and dropped to as low as 20 percent after corner
cracks appeared
Section 9, Doweled with Concrete Shoulder and Tie Bars, Normal Lane Width
Edge surface deflections under the influence of a 90- kN test load were on the order of 0.8
to 1.8 mm, before any cracks appeared. No dramatic difference in edge deflections could be
detected after the appearance of cracks.
LTE values varied between 80 and 100 percent for the duration of testing. The
appearance of cracks did not cause any reduction in LTE values; in fact in a few cases, it caused
an increase in LTE values.
v
Section 11, Doweled, Asphalt Shoulder, Widened Truck Lane ( 4.26 m)
Edge deflections under the influence of a 90- kN test load were on the order of 0.6 to 1.4
mm, before any cracks appeared and 0.8 to 1.5 mm after the appearance of cracks.
LTE values varied between 97 and 100 percent for the duration of testing. The
appearance of cracks did not cause any reduction in LTE values.
Conclusion
The advantages of dowels, tie bars, and a widened ( 4.26- m) lane are clearly illustrated in
the study. Even after the application of aggressive 150- kN loading onto the test sections, no
obvious LTE deterioration could be detected from the sections constructed with dowels, tie bars,
and widened lanes. Although significant cracks developed during the testing period, no
significant drop in LTE values could be detected after the formation of the cracks, which is an
indication of the effectiveness of the dowels to transfer load across joints, even after extensive
joint deterioration. The dowels had a significant influence in controlling slab edge movements.
In contrast to this, the plain aggregate interlock sections ( no dowels or tie bars)
experienced significant reductions in LTE after the appearance of corner cracks. The damaging
effect of repetitive loading caused a significant reduction in the life of the pavement in
comparisons with the reinforced jointed sections.
vi
vii
TABLE OF CONTENTS
Executive Summary ......................................................................................................................... i
Environmental Influences on the Behavior of the Concrete Slab................................................ i
Permanent Warping Due to Differential Shrinkage.................................................................... ii
Traffic- Induced Changes in the Behavior of the Concrete Slabs .............................................. iii
Comparing the Performance of the Three Different Structures................................................. iv
Section 7, Plain Joints ( Relying on Aggregate Interlock for Joint Load Transfer), Normal
Lane Width ............................................................................................................................. iv
Section 9, Doweled with Concrete Shoulder and Tie Bars, Normal Lane Width .................. iv
Section 11, Doweled, Asphalt Shoulder, Widened Truck Lane ( 4.26 m) ............................... v
Conclusion ............................................................................................................................... ... v
Table of Contents....................................................................................................................... .. vii
List of Figures........................................................................................................................ ..... xiii
List of Tables ............................................................................................................................ xxvii
1.0 Introduction................................................................................................................ 1
2.0 HVS Test Objectives and Scope Of Work................................................................. 3
3.0 HVS Test Program..................................................................................................... 5
3.1 HVS Instrumentation ...................................................................................................... 8
3.1.1 Joint Deflection Measuring Device ( JDMD)............................................................. 9
3.1.2 Multi- Depth Deflectometer ( MDD)......................................................................... 10
3.1.3 Thermocouples......................................................................................................... 22
3.2 HVS Loading Plan ........................................................................................................ 22
4.0 HVS Results............................................................................................................. 27
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4.1 Test 532FD.................................................................................................................... 28
4.1.1 Visual Observations ................................................................................................. 29
4.1.2 Joint Deflection Measuring Device ( JDMD) Results .............................................. 31
4.1.3 Joint Load Transfer Efficiency ( LTE) ..................................................................... 33
4.2 Test 533FD.................................................................................................................... 35
4.2.1 Visual Observations ................................................................................................. 35
4.2.2 Joint Deflection Measuring Device ( JDMD) Results .............................................. 36
4.2.3 Joint Load Transfer Efficiency ( LTE) ..................................................................... 38
4.2.4 Multi- Depth Deflectometer ( MDD) Results............................................................ 41
4.3 Test 534FD.................................................................................................................... 45
4.3.1 Visual Observations ................................................................................................. 46
4.3.2 Joint Deflection Measuring Device ( JDMD) Results .............................................. 46
4.3.3 Joint Load Transfer Efficiency ( LTE) ..................................................................... 51
4.3.4 Multi- Depth Deflectometer ( MDD) Results............................................................ 51
4.4 Test 535FD.................................................................................................................... 57
4.4.1 Visual observation ................................................................................................... 57
4.4.2 Joint Deflection Measuring Device ( JDMD) Results .............................................. 59
4.4.3 Joint Load Transfer Efficiency ( LTE) ..................................................................... 62
4.4.4 Multi- Depth Deflectometer ( MDD) Results............................................................ 64
4.5 Test 536FD.................................................................................................................... 69
4.5.1 Visual Observations ................................................................................................. 70
4.5.2 Joint Deflection Measuring Device ( JDMD) Results .............................................. 71
4.5.3 Multi- Depth Deflectometer ( MDD) Results............................................................ 86
ix
4.5.4 Joint Load Transfer Efficiency ( LTE) ..................................................................... 92
4.6 Test 537FD.................................................................................................................... 97
4.6.1 Visual Observations ................................................................................................. 97
4.6.2 Joint Deflection Measuring Device ( JDMD) Results ............................................ 100
4.6.3 Multi- Depth Deflectometer ( MDD) Results.......................................................... 107
4.6.4 Load Transfer Efficiency ( LTE) ............................................................................ 120
4.7 Test 538FD.................................................................................................................. 125
4.7.1 Visual Observations ............................................................................................... 126
4.7.2 Joint Deflection Measuring Device ( JDMD) Results ............................................ 128
4.7.3 Multi- Depth Deflectometer ( MDD) Results.......................................................... 140
4.7.4 Load Transfer Efficiency ( LTE) ............................................................................ 141
4.8 Test 539FD.................................................................................................................. 145
4.8.1 Visual Observations ............................................................................................... 146
4.8.2 Joint Deflection Measuring Device ( JDMD) Results ............................................ 148
4.8.3 Joint Load Transfer Efficiency ( LTE) ................................................................... 151
4.8.4 Multi- Depth Deflectometer ( MDD) Elastic Deflection Results ............................ 152
4.8.5 Multi- Depth Deflectometer ( MDD) Permanent Deformation Results .................. 157
4.9 Test 540FD.................................................................................................................. 161
4.9.1 Visual Observations ............................................................................................... 161
4.9.2 Joint Deflection Measuring Device ( JDMD) Results ............................................ 163
4.9.3 Joint Load Transfer Efficiency ( LTE) ................................................................... 166
4.9.4 Multi- Depth Deflectometer ( MDD) Elastic Deflection Results ............................ 167
4.9.5 Multi- Depth Deflectometer ( MDD) Permanent Deformation Data....................... 171
x
4.10 Test 541FD.................................................................................................................. 175
4.10.1 Visual Observations............................................................................................ 175
4.10.2 Joint Deflection Measuring Device ( JDMD) Results ......................................... 176
4.10.3 Joint Load Transfer Efficiency ( LTE) ................................................................ 179
4.11 Test 541FD Phase II.................................................................................................... 180
4.11.1 Visual Observations............................................................................................ 181
4.11.2 Joint Deflection Measuring Device ( JDMD) Results ......................................... 182
4.11.3 Joint Load Transfer Efficiency ( LTE) ................................................................ 189
4.11.4 Permanent Deformation ...................................................................................... 190
5.0 Falling Weight Deflectometer ( FWD) Results ...................................................... 195
5.1 Available Data and Analysis Methodology ................................................................ 196
5.2 Test Configuration ...................................................................................................... 199
5.2.1 Principal Effects..................................................................................................... 199
5.3 Analysis of Maximum Deflections ............................................................................. 202
5.3.1 Measurements Recorded Prior to Concrete Construction...................................... 202
5.3.2 Measurements Taken After Concrete Construction............................................... 204
5.4 Load Transfer Efficiency Across Joints...................................................................... 213
5.5 Deflections Before and After HVS Testing ................................................................ 229
5.5.1 Test 532FD ( Section 7: No Dowels or Tie Bars)................................................... 230
5.5.2 Test 533FD ( Section 7: No Dowels or Tie Bars)................................................... 231
5.5.3 Test 534FD ( Section 7: No Dowels or Tie Bars)................................................... 232
5.5.4 Test 535FD ( Section 7: No Dowels or Tie Bars)................................................... 233
5.5.5 Test 536FD ( Section 9: Dowels and Tie Bars) ...................................................... 234
xi
5.5.6 Test 537FD ( Section 9: Dowels and Tie Bars) ...................................................... 235
5.5.7 Test 538FD ( Section 9: Dowels and Tie Bars) ...................................................... 236
5.5.8 Test 539FD ( Section 11: Dowels, No Tie Bars, Widened Truck Lane) ................ 237
5.5.9 Test 540FD ( Section 11: Dowels, No Tie Bars, Widened Truck Lane) ................ 238
5.5.10 Test 541FD ( Section 11: Dowels, No Tie Bars, Widened Truck Lane)............. 239
5.5.11 Observations and Conclusions............................................................................ 240
5.6 Back- calculated Stiffnesses......................................................................................... 240
5.7 Summary and Conclusions.......................................................................................... 249
6.0 PCC Core Measurements ( North Tangent)............................................................ 251
6.1 Cores taken 40 days after construction ....................................................................... 251
6.1.1 Slab Thickness ....................................................................................................... 254
6.1.2 Core Densities........................................................................................................ 254
6.1.3 Compressive Strength ............................................................................................ 255
6.2 Observations from Cores Taken After HVS Testing .................................................. 256
6.2.1 Slab Thickness ....................................................................................................... 256
6.2.2 Instrument Positioning ........................................................................................... 260
6.2.3 Crack Mechanisms................................................................................................. 262
6.3 Observations and Comments on Day/ Night Cores Taken in February 2001.............. 267
6.3.1 Day/ Night Measurements of Cores at Joints ......................................................... 268
6.3.2 Day/ Night Measurements of Cracks through Joints .............................................. 269
6.3.3 Day/ Night Measurements of Normal Surface Cracks............................................ 271
6.3.4 Dowel Bar Placement Measurements .................................................................... 272
7.0 Discussion of HVS Test Results and Conclusions ................................................ 275
xii
7.1 Deflection Profiles ...................................................................................................... 276
7.1.1 Section 7: No Dowels, No Tie Bars, Asphalt Shoulder ( Tests 532– 535FD)......... 288
7.1.2 Section 9: Dowels, Tied Concrete Shoulder ( Tests 536FD– 538FD)..................... 289
7.1.3 Section 11: Dowels, Asphalt Shoulder, Widened ( 4.26- m) Truck Lane ( Tests
539FD– 541FD).................................................................................................................... 291
7.2 Influence of Main Test Variables................................................................................ 292
7.2.1 Dowels ................................................................................................................... 292
7.2.2 Widened ( 4.26- m) Truck Lane Slabs..................................................................... 293
7.3 General Conclusions ................................................................................................... 295
8.0 References.............................................................................................................. 297
9.0 Appendix A: Stripmaps Showing FWD Deflections ............................................. 299
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LIST OF FIGURES
Figure 1. Layout of HVS testing areas on the North Tangent. ........................................................ 6
Figure 2. Illustration of the placement of JDMD instruments and their numbering with
respect to the test sections...................................................................................... 10
Figure 3. Instrumentation layout of Test Section 532FD. ............................................................. 12
Figure 4. Instrumentation layout of Test Section 533FD. ............................................................. 13
Figure 5. Instrumentation layout of Test Section 534FD. ............................................................. 14
Figure 6. Instrumentation layout of Test Section 535FD. ............................................................. 15
Figure 7. Instrumentation layout of Test Section 536FD. ............................................................. 16
Figure 8. Instrumentation layout of Test Section 537FD. ............................................................. 17
Figure 9. Instrumentation layout of Test Section 538FD. ............................................................. 18
Figure 10. Instrumentation layout of Test Section 539FD. ........................................................... 19
Figure 11. Instrumentation layout of Test Section 540FD. ........................................................... 20
Figure 12. Instrumentation layout of Test Section 541FD. ........................................................... 21
Figure 13. Schematic of crack pattern, Test 532FD. ..................................................................... 30
Figure 14. Composite image of Test 532FD showing cracks........................................................ 30
Figure 15. Plot of JDMD deflections and temperature versus load repetitions, Test 532FD........ 32
Figure 16. Plot of LTE and temperature versus load repetitions, Test 532FD. ............................. 34
Figure 17. Schematic of crack pattern, Test 533FD. ..................................................................... 37
Figure 18. Composite image of Test 533FD showing cracks........................................................ 37
Figure 19. Plot of JDMD deflections and temperature versus load repetitions, Test 533FD........ 39
Figure 20. Plot of LTE and temperature versus load repetitions, Test 533FD. ............................. 40
Figure 21. Plot of MDD 14 deflections and temperature versus load repetitions, Test 533FD. ... 43
xiv
Figure 22. Plot of MDD 15 deflections and temperature versus load repetitions, Test 533FD. ... 44
Figure 23. Schematic of crack pattern, Test 534FD. ..................................................................... 47
Figure 24. Composite image of Test 534FD showing cracks........................................................ 47
Figure 25. Plot of JDMD deflections and temperature versus load repetitions ( entire loading
sequence), Test 534FD. ......................................................................................... 48
Figure 26. Plot of JDMD deflections and temperature versus load repetitions ( 1M repetitions
to end of test), Test 534FD. ................................................................................... 50
Figure 27. Plot of LTE and temperature versus load repetitions, Test 534FD. ............................. 52
Figure 28. Plot of MDD 12 deflections and temperature versus load repetitions, Test 534FD. ... 53
Figure 29. Plot of MDD 13 deflections and temperature versus load repetitions, Test 534FD. ... 54
Figure 30. Plot of MDD 12 permanent deformation and temperature versus load repetitions,
Test 534FD............................................................................................................. 56
Figure 31. Schematic of crack pattern, Test 535FD. ..................................................................... 58
Figure 32. Composite image of Test 535FD showing cracks........................................................ 58
Figure 33. Plot of JDMD deflections and temperature versus load repetitions, Test 535FD........ 60
Figure 34. Plot of LTE and temperature versus load repetitions, Test 535FD. ............................. 63
Figure 35. Plot of MDD 11 deflections and temperature versus load repetitions, Test 535FD. ... 66
Figure 36. Plot of MDD 11 permanent deformation and temperature versus load repetitions,
Test 535FD............................................................................................................. 68
Figure 37. Composite image of Test 536FD.................................................................................. 70
Figure 38. Plot of JDMD deflections and temperature versus load repetitions, 90- kN test
load, Test 536FD.................................................................................................... 72
xv
Figure 39. Plot of JDMD deflections and temperature versus load repetitions; 90-, 110-,
130-, and 150- kN test loads; Test 536FD. ............................................................. 73
Figure 40. Plot of JDMD deflections and temperature versus load repetitions, 150- kN test
load, Test 536FD.................................................................................................... 74
Figure 41. Joint deflections and the effect of wheel load repetitions, Test 536FD. ...................... 75
Figure 42. Effect of wheel load repetitions on midspan and horizontal deflections, Test
536FD. ................................................................................................................... 79
Figure 43. Effect of temperature on joint deflections, Test 536FD............................................... 81
Figure 44. Effect of temperature on midspan and horizontal deflections, Test 536FD................. 84
Figure 45. Relationship between temperature and joint deflection, Test 536FD. ......................... 85
Figure 46. Effect of wheel load repetitions on MDD deflections, Test 536FD............................. 87
Figure 47. Plot of MDD 10 permanent deformation and temperature versus load repetitions,
Test 536FD............................................................................................................. 89
Figure 48. Plot of MDD permanent deformation differentials and temperature versus load
repetitions, Test 536FD.......................................................................................... 91
Figure 49. Joint load transfer efficiency at Joints 26 and 27, Test 536FD. ................................... 93
Figure 50. Comparison of joint deflections on either side of Slab 27 ( Joints 26 and 27), Test
536FD. ................................................................................................................... 94
Figure 51. Plot of LTE and temperature versus load repetitions, Test 536FD. ............................. 95
Figure 52. Joint load transfer efficiency at Joints 26 and 27, Test 536FD. ................................... 96
Figure 53. Schematic of crack pattern, Test 537FD. ..................................................................... 98
Figure 54. Composite image of Test 537FD showing cracks........................................................ 98
Figure 55. Plot of JDMD deflections and temperature versus load repetitions, Test 537FD...... 101
xvi
Figure 56. Effect of wheel load repetitions on joint deflections, Test 537FD............................. 102
Figure 57. Effect of wheel load repetitions on mid- span and horizontal deflections, Test
537FD. ................................................................................................................. 106
Figure 58. Effect of temperature on joint deflections, Test 537FD............................................. 108
Figure 59. Effect of temperature on mid- span and horizontal deflections, Test 537FD. ............ 109
Figure 60. Effect of temperature and joint deflections, Test 537FD. .......................................... 110
Figure 61. Plost of MDD 8 deflections and temperature versus load repetitions, Test 537FD... 112
Figure 62. Plot of MDD 9 deflections and temperature versus load repetitions, Test 537FD. ... 113
Figure 63. Plot of MDD 8 permanent deformation and temperature versus load repetitions,
Test 537FD........................................................................................................... 115
Figure 64. Plot of MDD 8 permanent deformation differentials and temperature versus load
repetitions, Test 537FD........................................................................................ 116
Figure 65. Plot of MDD 9 permanent deformation and temperature versus load repetitions,
Test 537FD........................................................................................................... 117
Figure 66. Plot of MDD 9 permanent deformation differentials and temperature versus load
repetitions, Test 537FD........................................................................................ 118
Figure 67. Joint load transfer efficiency at Joints 22 and 23, Test 537FD. ................................. 121
Figure 68. Comparison of joint deflections on either side of Slab 23 ( Joints 22 and 23), Test
537FD. ................................................................................................................. 123
Figure 69. Plot of LTE and temperature versus load repetitions, Test 537FD. ........................... 124
Figure 70. Joint load transfer efficiency at Joints 22 and 23, Test 537FD. ................................. 125
Figure 71. Schematic of crack pattern, Test 538FD. ................................................................... 127
Figure 72. Composite image of Test 538FD showing cracks...................................................... 127
xvii
Figure 73. Plot of JDMD deflections and temperature versus load repetitions, Test 538FD...... 129
Figure 74. Effect of wheel load repetitions on joint deflections, Test 538FD............................. 130
Figure 75. Effect of wheel load repetitions on mid- span and horizontal deflections, Test
538FD. ................................................................................................................. 133
Figure 76. Effect of temperature on joint deflections, Test 538FD............................................. 135
Figure 77. Effect of temperature on mid- span and horizontal deflections, Test 538FD. ............ 136
Figure 78. Relationship between temperature and joint deflection, Test 538FD. ....................... 137
Figure 79. Plot of JDMD permanent deformation and temperature versus load repetitions,
Test 538FD........................................................................................................... 139
Figure 80. Comparison of deflections on both sides of Joints 18 and 19, Test 538FD. .............. 142
Figure 81. Comparison of deflections on either side of Slab 19 ( Joints 18 and 19), Test
538FD. ................................................................................................................. 143
Figure 82. Plot of LTE and temperature versus load repetitions, Test 538FD. ........................... 144
Figure 83. Comparison of LTE at each end of Slab 19 ( Joints 18 and 19), Test 538FD............. 145
Figure 84. Schematic of crack pattern, Test 539FD. ................................................................... 147
Figure 85. Composite image of Test 539FD showing cracks...................................................... 147
Figure 86. Plot of JDMD deflections and temperature versus load repetitions, Test 539FD...... 150
Figure 87. Plot of MDD 5 deflections and temperature versus load repetitions, Test 539FD. ... 154
Figure 88. Plot of MDD 4 deflections and temperature versus load repetitions, Test 539FD. ... 155
Figure 89. Plot of MDD 5 permanent deformation and temperature versus load repetitions,
Test 539FD........................................................................................................... 159
Figure 90. Plot of MDD 4 permanent deformation and temperature versus load repetitions,
Test 539FD........................................................................................................... 160
xviii
Figure 91. Schematic of crack pattern, Test 540FD. ................................................................... 162
Figure 92. Composite image of Section 540FD showing crack pattern. ..................................... 162
Figure 93. Plot of JDMD deflections and temperature versus load repetitions, Test 540FD...... 165
Figure 94. Plot of MDD 2 deflections and temperature versus load repetitions, Test 540FD. ... 169
Figure 95. Plot of MDD3 deflections and temperature versus load repetitions, Test 540FD. .... 170
Figure 96. Plot of MDD 2 permanent deformation and temperature versus load repetitions,
Test 540FD........................................................................................................... 173
Figure 97. Plot of MDD 3 permanent deformation and temperature versus load repetitions,
Test 540FD........................................................................................................... 174
Figure 98. Composite image of Test Section 541FD................................................................... 176
Figure 99. Plot of JDMD deflections and temperature versus load repetitions, Test 541FD...... 178
Figure 100. Composite image of Test 541FD phase II................................................................ 181
Figure 101. Plot of JDMD deflections versus test load at the start of Test 541FD Phase II. ...... 183
Figure 102. Plot of JDMD deflections and temperature versus load repetitions ( 40- kN test
load), Test 541FD Phase II. ................................................................................. 185
Figure 103. Plot of JDMD deflections and temperature versus load repetitions ( 90- kN test
load), Test 541FD Phase II. ................................................................................. 186
Figure 104. Plot of JDMD deflections and temperature versus load repetitions ( 150- kN test
load), Test 541FD Phase II. ................................................................................. 187
Figure 105. Plot of JDMD permanent deformation and temperature versus load repetitions
( first 125,000 repetitions), Test 541FD Phase II. ................................................ 191
Figure 106. Plot of JDMD permanent displacement and temperature versus load repetitions,
Test 541FD Phase II. ........................................................................................... 192
xix
Figure 107. FWD measurement program relative to HVS program............................................ 196
Figure 108. General setup for FWD measurement locations....................................................... 200
Figure 109. Sensor setup for measurements across transverse and longitudinal joints............... 200
Figure 110. Maximum deflection measured along slab centerline prior to concrete
construction.......................................................................................................... 203
Figure 111. Maximum deflection measured along K- rail edge prior to concrete construction... 203
Figure 112. Central deflection along centerline at different concrete ages, Section 11
( doweled joints with asphalt concrete shoulder and widened truck lane). .......... 206
Figure 113. Central deflection along centerline at different surface temperatures, Section 11
( doweled joints with asphalt concrete shoulder and widened truck lane), .......... 207
Figure 114. Central deflection along centerline at different concrete ages, Section 9
( doweled joints and tie bars at concrete shoulder)............................................... 207
Figure 115. Central deflection along centerline at different temperatures, Section 9 ( doweled
joints and tie bars at concrete shoulder). ............................................................. 208
Figure 116. Central deflection along centerline at different concrete ages, Section 7 ( no
dowels or tie bars, asphalt concrete shoulder). .................................................... 208
Figure 117. Central deflection along centerline at different temperatures, Section 7 ( no
dowels or tie bars, asphalt concrete shoulder). .................................................... 209
Figure 118. Central deflection along K- rail at different concrete ages, Section 11 ( doweled
joints with asphalt concrete shoulder and widened truck lane). .......................... 210
Figure 119. Central deflection along K- rail at different temperatures, Section 11 ( doweled
joints with asphalt concrete shoulder and widened truck lane). .......................... 211
xx
Figure 120. Central deflection along K- rail at different concrete ages, Section 9 ( doweled
joints and tie bars at concrete shoulder). ............................................................. 211
Figure 121. Central deflection along K- rail at different temperatures, Section 9 ( doweled
joints and tie bars at concrete shoulder). ............................................................. 212
Figure 122. Central deflection along K- rail at different concrete ages, Section 7 ( no dowels
or tie bars, asphalt concrete shoulder). ................................................................ 212
Figure 123. Central deflection along K- rail at different temperatures, Section 7 ( no dowels
or tie bars, asphalt concrete shoulder). ................................................................ 213
Figure 124. Typical deflection profile measured across a transverse joint along slab
centerline.............................................................................................................. 214
Figure 125. Typical deflection profile measured across a transverse joint along slab edge ( K-rail
side). .............................................................................................................. 214
Figure 126. LTE across transverse joints at concrete ages of less than 300 days. ...................... 218
Figure 127. LTE across transverse joints at concrete ages of more than 900 days ( only day
measurements are shown). ................................................................................... 219
Figure 128. Transverse joint LTE versus concrete age, Section 11 ( doweled joints with
asphalt concrete shoulder and widened truck lane). ............................................ 219
Figure 129. Transverse joint LTE versus surface temperature, Section 11 ( doweled joints
with asphalt concrete shoulder and widened truck lane). .................................... 220
Figure 130. Transverse joint LTE versus concrete age, Section 9 ( doweled joints and tie bars
at concrete shoulder)............................................................................................ 220
Figure 131. Transverse joint LTE versus surface temperature, Section 9 ( doweled joints and
tie bars at concrete shoulder). .............................................................................. 221
xxi
Figure 132. Transverse joint LTE versus concrete age, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder). .................................................................................. 221
Figure 133. Transverse joint LTE versus surface temperature, Section 7 ( no dowels or tie
bars, asphalt concrete shoulder)........................................................................... 222
Figure 134. Longitudinal joint LTE versus concrete age at slab center along K- rail edge,
Section 11 ( doweled joints with asphalt concrete shoulder and widened truck
lane). .................................................................................................................... 223
Figure 135. Longitudinal joint LTE versus surface temperature at slab center along K- rail
edge, Section 11 ( doweled joints with asphalt concrete shoulder and widened
truck lane). ........................................................................................................... 223
Figure 136. Longitudinal joint LTE versus concrete age at slab center along K- rail edge,
Section 9 ( doweled joints and tie bars at concrete shoulder)............................... 224
Figure 137. Longitudinal joint LTE versus surface temperature at slab center along K- rail
edge, Section 9 ( doweled joints and tie bars at concrete shoulder). .................... 224
Figure 138. Longitudinal joint LTE versus concrete age at slab center along K- rail edge,
Section 7 ( no dowels or tie bars, asphalt concrete shoulder)............................... 225
Figure 139. Longitudinal joint LTE versus surface temperature at slab center along K- rail
edge, Section 7 ( no dowels or tie bars, asphalt concrete shoulder). .................... 225
Figure 140. Longitudinal joint LTE versus concrete age at slab corner along K- rail edge,
Section 11 ( doweled joints with asphalt concrete shoulder and widened truck
lane). .................................................................................................................... 226
xxii
Figure 141. Longitudinal joint LTE versus surface temperature at slab corner along K- rail
edge, Section 11 ( doweled joints with asphalt concrete shoulder and widened
truck lane). ........................................................................................................... 227
Figure 142. Longitudinal joint LTE versus concrete age at slab corner along K- rail edge,
Section 9 ( doweled joints and tie bars at concrete shoulder)............................... 227
Figure 143. Longitudinal joint LTE versus surface temperature at slab corner along K- rail
edge, Section 9 ( doweled joints and tie bars at concrete shoulder). .................... 228
Figure 144. Longitudinal joint LTE versus concrete age at slab corner along K- rail edge,
Section 7 ( no dowels or tie bars, asphalt concrete shoulder)............................... 228
Figure 145. Longitudinal joint LTE versus surface temperature at slab corner along K- rail
edge, Section 7 ( no dowels or tie bars, asphalt concrete shoulder). .................... 229
Figure 146. Impact of HVS testing on central deflection measured at slab center ( Test
532FD). ................................................................................................................ 230
Figure 147. Impact of HVS testing on LTE at transverse joints measured along slab
centerline ( Test 532FD). ...................................................................................... 230
Figure 148. Impact of HVS testing on central deflection measured at slab center ( Test
533FD). ................................................................................................................ 231
Figure 149. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 533FD). ...................................................................................... 231
Figure 150. Impact of HVS testing on central deflection measured at slab center ( Test
534FD). ................................................................................................................ 232
Figure 151. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 534FD). ...................................................................................... 232
xxiii
Figure 152. Impact of HVS testing on central deflection measured at slab center ( Test
535FD). ................................................................................................................ 233
Figure 153. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 535FD). ...................................................................................... 233
Figure 154. Impact of HVS testing on central deflection measured at slab center ( Test
536FD). ................................................................................................................ 234
Figure 155. Impact of HVS testing on central LTE measured at transverse joints along slab
centerline ( Test 536FD). ...................................................................................... 234
Figure 156. Impact of HVS testing on central deflection measured at slab center ( Test
537FD). ................................................................................................................ 235
Figure 157. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 537FD). ...................................................................................... 235
Figure 158. Impact of HVS testing on central deflection measured at slab center ( Test
538FD). ................................................................................................................ 236
Figure 159. Impact of HVS testing on LTE measured at transverse joint along slab
centerline ( Test 538FD). ...................................................................................... 236
Figure 160. Impact of HVS testing on central deflection measured at slab center ( Test
539FD). ................................................................................................................ 237
Figure 161. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 539FD). ...................................................................................... 237
Figure 162. Impact of HVS testing on central deflection measured at slab center ( Test
540FD). ................................................................................................................ 238
xxiv
Figure 163. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 540FD). ...................................................................................... 238
Figure 164. Impact of HVS testing on central deflection measured at slab center ( Test
541FD). ................................................................................................................ 239
Figure 165. Impact of HVS testing on LTE measured at transverse joints along slab
centerline ( Test 541FD). ...................................................................................... 239
Figure 166. Back- calculated stiffness 1 day after concrete construction. ................................... 242
Figure 167. Back- calculated stiffness 7 days after concrete construction................................... 242
Figure 168. Back- calculated stiffness 49 days after concrete construction................................. 243
Figure 169. Back- calculated stiffness 90 days after concrete construction................................. 243
Figure 170. Back- calculated stiffness 200 days after concrete construction............................... 244
Figure 171. Back- calculated stiffness 270 days after concrete construction............................... 244
Figure 172. Back- calculated stiffness 966 days after concrete construction ( daytime
measurement)....................................................................................................... 245
Figure 173. Back- calculated stiffness 966 says after concrete construction ( daytime
measurement)....................................................................................................... 245
Figure 174. Concrete stiffness at different ages, Section 11 ( doweled joints with asphalt
concrete shoulder and widened truck lane).......................................................... 246
Figure 175. Concrete stiffness at different ages, Section 9 ( doweled joints and tie bars at
concrete shoulder)................................................................................................ 246
Figure 176. Concrete stiffness at different ages, Section 7 ( no dowels or tie bars, asphalt
concrete shoulder)................................................................................................ 247
xxv
Figure 177. Subgrade stiffness at different ages, Section 11 ( doweled joints with asphalt
concrete shoulder and widened truck lane).......................................................... 247
Figure 178. Subgrade stiffness at different ages, Section 7 ( no dowels or tie bars, asphalt
concrete shoulder)................................................................................................ 248
Figure 179. Subgrade stiffness at different ages, Section 9 ( doweled joints and tie bars at
concrete shoulder)................................................................................................ 248
Figure 180. Relationship between compressive strength and concrete density........................... 255
Figure 181a. Variation in deflection with respect to N10, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder), Test 532FD. ............................................................. 278
Figure 181b. Variation in deflection with respect to N10, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder), Test 534FD. ............................................................. 279
Figure 181c. Variation in deflection with respect to N10, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder), Test 533FD. ............................................................. 280
Figure 181d. Variation in deflection with respect to N10, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder), Test 535FD. ............................................................. 281
Figure 182a. Variation in deflection with respect to N10, Section 9 ( doweled joints and tie
bars at concrete shoulder), Test 536FD. .............................................................. 282
Figure 182b. Variation in deflection with respect to N10, Section 9 ( doweled joints and tie
bars at concrete shoulder), Test 537FD. .............................................................. 283
Figure 182c. Variation in deflection with respect to N10, Section 9 ( doweled joints and tie
bars at concrete shoulder), Test 538FD. .............................................................. 284
Figure 183a. Variation in deflection with respect to N10, Section 11 ( doweled joints with
asphalt concrete shoulder and widened truck lane). Test 539FD. ....................... 285
xxvi
Figure 183b. Variation in deflection with respect to N10, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder), Test 540FD. ............................................................. 286
Figure 183c. Variation in deflection with respect to N10, Section 7 ( no dowels or tie bars,
asphalt concrete shoulder), Test 541FD. ............................................................. 287
xxvii
LIST OF TABLES
Table 1 HVS Tests on the North Tangent............................................................................. 6
Table 2 Slab Dimensions ...................................................................................................... 7
Table 3 Location of MDDs Placed on the North Tangent HVS Sections .......................... 11
Table 4 Loading Plan for the HVS Tests ............................................................................ 23
Table 5 JDMD Deflections, Test 532FD ............................................................................ 31
Table 6 Load Transfer Efficiency, Test 532FD .................................................................. 33
Table 7 JDMD Deflections, Test 533FD ............................................................................ 36
Table 8 Load Transfer Efficiency, Test 533FD .................................................................. 41
Table 9 MDD Deflections, Test 533FD.............................................................................. 42
Table 10 JDMD Deflections, Test 534FD ............................................................................ 46
Table 11 MDD Deflections, Test 534FD.............................................................................. 51
Table 12 MDD 12 Permanent Deformation, Test 534FD..................................................... 55
Table 13 JDMD Deflections, Test 535FD ............................................................................ 59
Table 14 Load Transfer Efficiency, Test 535FD .................................................................. 62
Table 15 MDD Deflections, Test 535FD.............................................................................. 65
Table 16 MDD Permanent Deformation, Test 535FD.......................................................... 67
Table 17 JDMD Deflections to 750,000 repetitions, 90- kN Load, Test 536FD................... 76
Table 18 Deflections After 500 Repetitions of Various Aircraft Wheel Loads, Test
536FD) ................................................................................................................... 77
Table 19 Test Temperature Conditions, Test 536FD............................................................ 82
Table 20 JDMD Deflections ( Test loads 40 kN, 70 kN, 90 kN), Test 539FD ................... 149
Table 21 Load Transfer Efficiency, Test 539FD ................................................................ 152
xxviii
Table 22 MDD 5 Deflections ( Test Loads 40 kN, 70 kN, 90 kN), Test 539FD................. 153
Table 23 MDD 4 Deflections ( Test loads 40 kN, 70 kN, 90 kN) Test 539FD ................... 153
Table 24 MDD 5 Permanent Deformation, Test 539FD..................................................... 158
Table 25 MDD 4 Permanent Deformation, Test 539FD..................................................... 158
Table 26 JDMD Deflections, ( Test Load 40 kN, 90 kN, 150 kN) Test 540FD.................. 164
Table 27 Load Transfer Efficiency, Test 540FD ................................................................ 166
Table 28 MDD 2 Deflections ( Test load 40 kN, 90 kN, 150 kN), Test 540FD.................. 168
Table 29 MDD 3 Deflections ( Test load 40 kN, 90 kN, 150 kN), Test 540FD.................. 168
Table 30 MDD 2 Permanent Deformation, Test 540FD..................................................... 172
Table 31 MDD 3 Permanent Deformation, Test 540FD..................................................... 172
Table 32 JDMD Deflections ( Test Loads 70 kN, 90 kN, 150 kN) Test 541FD ................. 177
Table 33 Load Transfer Efficiency, Test 541FD ................................................................ 179
Table 34 Relationship between Test Loads and Measured Deflections, Test 541FD
Phase II ................................................................................................................ 182
Table 35 JDMD Deflections, Test Load 40 kN, Test 541FD Phase II ............................... 183
Table 36 JDMD Deflections, Test Load 90 kN, Test 541FD Phase II ............................... 184
Table 37 Average of all 40- kN Deflection, Test 541FD .................................................... 188
Table 38 Load Transfer Efficiency at Various Loads, Test 541FD Phase II...................... 189
Table 39 Load Transfer Efficiency, Test Load 40 kN, Test 541FD Phase II ..................... 189
Table 40 Summary of Relevant FWD Tests Performed on North Tangent........................ 197
Table 41 Summary of Average Central Deflections Along Slab Centerline ...................... 205
Table 42 Summary of Average Central Deflection Measured Along Slab Edge ( K- rail
Side) ..................................................................................................................... 206
xxix
Table 43 Summary of LTE Across Transverse Joints Along Slab Centerline ................... 215
Table 44 Summary of LTE Across Longitudinal Joints Along K- Rail Edge, Slab
Center................................................................................................................... 216
Table 45 Summary of LTE Across Longitudinal Joints Along K- Rail Edge, At Slab
Corner .................................................................................................................. 216
Table 46 Properties and Statistics of Cores Taken Approximately 40 Days After
Construction......................................................................................................... 252
Table 47 Core Height Statistics of Cores Taken after HVS Testing on Section 7 ............. 257
Table 48. Core Height Statistics of Cores Taken After HVS Testing on Section 9 ............ 258
Table 49 Core Height Statistics of Cores Taken After HVS Testing on Section 11 .......... 259
Table 50 Summary of Core Height Statistics...................................................................... 259
Table 51 Strain Gauge Positioning as Measured from Cores after HVS Testing............... 261
Table 52 Observations from Cores Taken Through Cracks on Section 7 .......................... 263
Table 53 Observations from Cores Taken Through Cracks on Section 9 .......................... 264
Table 54 Observations from Cores Taken Through Cracks on Section 11 ........................ 265
Table 55 Saw- cut and Core Height Statistics, Day/ Night Cores ........................................ 268
Table 56 Day/ Night Crack Widths at Bottom of Cores Drilled through Joints on the
North Tangent ...................................................................................................... 269
Table 57 Day/ Night Crack Widths at Bottom of Cores Drilled through Joints on the
South Tangent ...................................................................................................... 270
Table 58 Day/ Night Crack Widths from Cores Drilled on Cracks on the South Tangent.. 271
Table 59 Dowel Bar Placement Statistics........................................................................... 272
Table 60 Deflection Comparison: Plain Jointed versus Doweled Sections........................ 290
xxx
Table 61 Summary of JDMD Deflections for All Sections, 90- kN Test Load................... 294
1
1.0 INTRODUCTION
As part of the Caltrans Long Life Pavement Rehabilitation Strategies ( LLPRS), a
concrete pavement was constructed with a blend of fast- setting hydraulic cement concrete
( FSHCC) and Portland cement concrete ( PCC) on sections tangent to State Route 14 in
Palmdale, California. This pavement was evaluated using the Heavy Vehicle Simulator ( HVS).
The tests followed plans detailed in the Test Plan for CAL/ APT Goal LLPRS - Rigid Phase III
( 1). The concrete was specified to obtain a flexural strength of 2.8 MPa within 4 to 8 hours of
placement.
Two full- scale test sites, each approximately 210 m in length, were constructed. Each site
included three 70- m long test sections, for a total of six sections. The site tangent to the
southbound direction of SR 14 (“ South Tangent”) included sections with different thicknesses of
concrete placed on compacted granular base. The site tangent to the northbound direction
(“ North Tangent”) included three 200- mm thick concrete on cement treated base, with varying
design features: dowels, tied shoulders, widened lanes ( 2).
This report documents the results of the North Tangent test sections Another report
presents the results of the HVS tests on the South Tangent ( 3).
2
3
2.0 HVS TEST OBJECTIVES AND SCOPE OF WORK
The objectives of the accelerated pavement testing performed with HVS No. 2 ( HVS2) at
the Palmdale north tangent test sections were to evaluate the performance of full- scale
pavements with the selected design features ( dowels, tied slabs, and widened truck lanes) under
traffic loading with respect to fatigue cracking, corner cracking, and joint distress to determine
whether they will provide the performance desired by Caltrans. HVS trafficking is intended to
accelerate damage as much as possible within the time available, without overloading to an
extent that the distress mechanism is significantly different from that which would occur in the
field.
Ten HVS tests were undertaken on the North Tangent, State Route 14. This report
summarizes the results and first- level analysis of all HVS tests conducted on the North Tangent
at Palmdale. The primary purpose of a first- level HVS report is to present a complete and
validated set of HVS data without detailed analysis and interpretation of the data. The first- level
report is confined to the HVS data and associated test results from the HVS site. The conclusions
of the first- level report are therefore site specific with little interpretation and should not be
generalized.
Also documented are weather data during each test, visual distress, pavement response
measured by in- situ instrumentation ( thermocouples, joint deflection measuring devices, multi-depth
deflectometers), and periodic testing using the heavy weight deflectometer ( HWD). A
first- level summary is provided for each type of data.
All data presented in this report are included in the Caltrans/ University of California
Pavement Research Center electronic database ( 4).
4
5
3.0 HVS TEST PROGRAM
Three 70- m long test sections with 200- mm thick FSHCC were constructed at the north
tangent as follows:
• Section 7 was constructed with plain joints ( no dowels, relying on aggregate interlock
for load transfer across the joint) with an asphalt concrete shoulder and a normal lane
width of 3.66 m.
• Section 9 was constructed with dowels and tie bars and a normal lane width of 3.66
m. The dowels were placed parallel to the direction of trafficking ( i. e., square joints)
and the section was constructed with tie bars connected to a concrete shoulder.
• Section 11 consisted of a “ widened lane” ( lane width of 4.26 m) and doweled joints.
The dowels were placed parallel to the direction of trafficking and the section was
constructed with an asphalt concrete shoulder.
The aim of this series of tests was to evaluate the performance of the three different
pavement structures under the influence of accelerated trafficking, to do a direct comparison
between the performance of a plain jointed aggregate interlock structure, a doweled pavement
structure, and a concrete pavement constructed with a widened truck lane.
The HVS tests on the North Tangent are summarized in Table 1.
The layout of all sections with respect to the 210- m long full scale test section on the
northbound side is detailed in an earlier report ( 2). A graphical representation of the various
sections with respect to the 210- m long North Tangent testing area can be seen in Figure 1. Slab
dimensions, numbers, joint numbers, and joint spacing are summarized in Table 2. Complete
construction and dimension details for the various sections are found in Reference ( 2) and are
not repeated here.
6
Table 1 HVS Tests on the North Tangent
HVS Test
North Tangent
Section Number
Slab
Number* Start Date End Date Type of structure
532FD 7D 43 7- Jun- 99 26- Jul- 99
533FD 7C 39 6- Aug- 99 1- Nov- 99
534FD 7B 35 15- Dec- 99 14- Mar- 00
535FD 7A 32 29- Jan- 00 4- Apr- 00
No dowels,
asphalt shoulder
536FD 9A 27 17- Apr- 00 12- Jul- 00
537FD 9C 23 20- Jul- 00 21- Aug- 00
538FD 9D 19 3- Jan- 01 18- Jan- 01
Dowels, tied
concrete shoulder
539FD 11C 11 1- Sep- 01 29- Sep- 01
540FD 11B 7 8- Oct- 01 28- Nov- 01
541FD 11A 3 2- Dec- 01 27- Dec- 01
Dowels, asphalt
shoulder, widened
truck lane
* The HVS test was centered around this slab. Some areas of the adjacent slabs were also subjected to HVS
trafficking.
4.26 m
3.66 m
210 m ( Three sections, 70 m each)
Section 9
Dowels and tied
concrete shoulder
Section 7
No dowels,
asphalt shoulder
Section 11
Asphalt shoulder,
dowels and widened
truck lane
0.2 m
HVS testing areas within
each section
K- rail ( traffic barrier)
separating the test sections
from oncoming traffic
Figure 1. Layout of HVS testing areas on the North Tangent.
7
Table 2 Slab Dimensions
Test Slab Dimensions ( m)
Number
Section
Number
Slab
Number
Joint
Number Length Width Type of Structure
42 5.82 3.66
42
43 3.95 3.66
43
532FD 7
44 3.64 3.66
38 5.79 3.66
38
39 4.03 3.66
39
533FD 7
40 3.65 3.65
34 5.91 3.68
34
35 3.86 3.66
35
534FD 7
36 3.90 3.66
31 4.11 3.66
31
32 3.71 3.66
32
535FD 7
33 5.35 3.66
no dowels, asphalt
shoulder
26 5.81 3.66
26
27 3.96 3.66
27
536FD 9
28 3.62 3.66
22 5.78 3.66
22
23 3.94 3.66
23
537FD 9
24 3.66 3.66
18 5.86 3.66
18
19 3.92 3.66
19
538FD 9
20 3.75 3.66
dowels and tied to a
concrete shoulder
8
Table 2 ( continued)
Test Slab Dimensions ( m)
Number
Section
Number
Slab
Number
Joint
Number Length Width Type of Structure
10 5.86 4.26
10
11 3.85 4.26
11
539FD 11
12 3.71 4.26
6 5.86 4.26
6
7 3.80 4.26
7
540FD 11
8 3.80 4.26
2 5.91 4.26
2
3 3.89 4.26
3
541FD 11
4 3.67 4.26
dowels, asphalt
shoulder, and widened
truck lane
3.1 HVS Instrumentation
Test instruments used to monitor the functional and structural behavior of the pavement
under accelerated loading include the following:
• Joint Deflection Measuring Devices ( JDMD)
• Multi- depth Deflectometers ( MDD)
• Thermocouples ( TC)
• Visual surveys and photographs
The description and function of these instruments and their recording mechanisms are
described in previous reports ( 1– 3).
The HVS test pad ( 8 m × 1 m) extends over 3 slabs, the greater part of the test section
being over the middle slab as illustrated in Figure 2. During Tests 532FD and 533FD, the same
data acquisition system was used as during the South Tangent tests. From Test 534FD onwards,
a new automatic data acquisition system was implemented. This new system enabled data
9
recording on the fly ( automatically and without any operator intervention) and was able to record
more data from more instruments simultaneously than the previous system. As a result, more
instruments were installed and a different testing program was used than during the South
Tangent tests and the first two tests ( 532FD and 533FD) on the North Tangent.
3.1.1 Joint Deflection Measuring Device ( JDMD)
Joint Deflection Measuring Devices ( JDMDs) are linear variable displacement
transducers ( LVDTs) mounted on the concrete slab to measure joint movement, as shown in
Figure 2. Six of these instruments were used per test section ( JDMD numbers refer to layout
shown in Figure 2):
• one at the middle of the edge of the center slab ( JDMD 3),
• one on either side of the center slab at the corners ( two total – JDMD 2 and 4),
• one at the corners of the adjacent slabs bordering the center slab ( two total – JDMD 1
and 5), and
• a sixth JDMD ( JDMD 6) oriented horizontally to record the differential movement
across the transverse joint of the center slab and an adjacent slab.
During Test 532FD, only three JDMDs were used ( two for corner deflections on one
joint, and one for midspan edge deflections). During Test 533FD, only five JDMDs were used
( four for the measurement of corner deflections on the joints, and one for midspan edge
deflections).
The vertical JDMDs were anchored in the shoulder of the pavement with an anchor rod
isolated from the movement of the slabs. Thus, they provide measurements of the absolute
deflection of the slab. JDMD 6 measures the relative horizontal movement of the slab across the
10
Joint x
Joint x+ 1
JDMD 4
JDMD 3
JDMD 6
JDMD 2
JDMD 1
JDMD 5
Center Slab
( Slab x+ 1)
Adjacent Slab
( Slab x)
HVS Wheelpath
Adjacent Slab
( Slab x+ 2)
Figure 2. Illustration of the placement of JDMD instruments and their numbering with
respect to the test sections.
joint. JDMD 3 is also referred to as an “ edge deflection measuring device” ( EDMD) because it is
placed at an edge rather than a joint. Placement of the JDMDs in each section is shown in
Figures 3– 12.
3.1.2 Multi- Depth Deflectometer ( MDD)
MDDs were placed between the two wheel paths of the dual HVS loading wheels,
approximately 300 mm from the edge of the concrete slab. All MDDs were fitted with 4 in- depth
LVDTs, placed at various depths.
11
Seven of the ten HVS sections were instrumented with MDDs. MDDs were installed on
the tests and locations shown in Table 3. The complete instrument placement and locations are
also shown for all 10 tests in Figures 3 through 12.
Table 3 Location of MDDs Placed on the North Tangent HVS Sections
Test
Number
MDD ID
Numbers
Test Slab
Numbers 300 mm from Joint Number Type of Structure
42
42
43
43
532FD No MDDs
installed
44
14 39
533FD 39
15 40
12 35
534FD 35
13 36
32
535FD 11
between Joints 31 and 32 ( midspan Slab 32)
Section 7:
No dowels, asphalt
shoulder
536FD 10 27 between Joints 26 and 27 ( midspan Slab 27)
8 23
537FD 23
9 24
18
18
19
19
538FD No MDDs
installed
20
Section 9:
Dowels and tied to a
concrete shoulder
4 11
539FD 11
5 12
2 7
540FD 7
3 8
2
2
3
3
541FD No MDDs
installed
4
Section 11:
Dowels, asphalt
shoulder, and
widened truck lane
12
Figure 3. Instrumentation layout of Test Section 532FD.
13
Figure 4. Instrumentation layout of Test Section 533FD.
14
Figure 5. Instrumentation layout of Test Section 534FD.
15
Figure 6. Instrumentation layout of Test Section 535FD.
16
Figure 7. Instrumentation layout of Test Section 536FD.
17
Figure 8. Instrumentation layout of Test Section 537FD.
18
Figure 9. Instrumentation layout of Test Section 538FD.
19
Figure 10. Instrumentation layout of Test Section 539FD.
20
Figure 11. Instrumentation layout of Test Section 540FD.
21
Figure 12. Instrumentation layout of Test Section 541FD.
22
3.1.3 Thermocouples
Thermocouples were placed to measure temperatures in the 200- mm thick concrete slabs
at the surface and at depths of 100 and 200 mm at the following positions:
• inside the temperature box (“ TC Test Pad”),
• under the HVS in the shade ( TC Shade),
• at a location in which the thermocouple was completely exposed to direct sunlight
100 percent of the day ( TC Sun), and
• at a location between the HVS and the adjacent K- rail, partially exposed to the sun
but shaded part of the day from the HVS and the K- rail ( TC K- rail).
This thermocouple configuration was used for Test Sections 534FD through 541FD.
Sections 532FD and 533FD were tested using the old data acquisition system and a
different thermocouple layout was used. During Test 532FD, one thermocouple “ stack” ( 0, 100,
200- mm depths) was installed at the edge of Slab 43 inside the temperature control box. During
Test 533FD, one stack was installed at the edge of Slab 39, also inside the temperature control
box. The detailed layouts of all sections, including placement of all instrumentation with relation
to the various concrete slabs, are presented in Figures 3– 12.
3.2 HVS Loading Plan
To investigate the various effects of temperature, water, and loading, the test sections
were subjected to different loading and environmental conditions. Table 4 details the various
combinations which were used during the tests on the North Tangent. The normal dual wheel
configuration ( tire pressure = 690 kPa) was used during the tests except in certain cases where
the aircraft wheel ( tire pressure = 1,100 kPa) was used ( see Table 4). The aircraft wheel was
used
23
Table 4 Loading Plan for the HVS Tests
Test Repetitions Actual Repetitions
Number from to
Load kN Dual
Wheel
Temperature
Control Water Added? Loading Type per Load Cycle Total
0 7,794 40 dry 7,794
532FD 7,794 16,543 40 8,749
16,543 202,302 70
yes wet unidirectional
185,759
202,302
0 44,164 40 44,164
533FD 44,164 254,167 70 210,003
254,167 371,150 90
yes dry unidirectional
116,983
371,150
0 126,580 40 126,580
534FD 126,580 984,602 70 858,022
984,602 1,284,360 90
yes dry bi- directional
299,758
1,284,360
535FD 0 80,002 90 yes dry bi- directional 80,002 80,002
0 750,000 90 750,000
750,000 750,500 70 aircraft 500
750,500 751,000 90 aircraft 500
751,000 751,500 110 aircraft 500
751,500 752,000 130 aircraft 500
752,000 840,450 150 aircraft
yes
88,450
536FD
840,450 992,782 150 aircraft ambient
dry bi- directional
152,332
992,782
0 13,230 40 13,230
13,230 13,730 70 dry 500
537FD 13,730 323,734 90 310,004
323,734 388,736 150 aircraft
ambient
bi- directional
65,002
388,736
538FD 05 00 150809 ,382 7900 ambient dry bi- directional 150808 ,882 189,382
0 13,342 40 13,342
539FD 13,342 13,842 70 500
13,842 318,846 90
ambient dry bi- directional
305,004
318,846
0 13,003 40 13,003
540FD 13,003 405,065 90 392,062
405,065 547,463 150 aircraft
yes dry bi- directional
142,398
547,463
0 500 70 500
541FD 500 168,277 90 167,777
168,277 278,288 150 aircraft
ambient dry bi- directional
110,011
278,288
24
for cases in which the pavement response under a heavy load ( 150 kN) was investigated. The
normal dual tires may only carry loads of up to 100 kN.
It is important to note the following:
• During HVS Tests 532FD and 533FD ( and all tests done on the South Tangent), the
old data acquisition system ( DAS) was used. In order to perform data collection with
the old DAS, the HVS test wheel was set at creep speed ( 2 km/ h). All data collection
and subsequent responses measured by the various instruments were performed under
the influence of this slow moving wheel.
• During Tests 534FD through 541FD, the new DAS was used. This DAS takes
readings on the fly at the regular traffic speed of about 7 km/ h.
Although not as critical for concrete as for flexible pavement structures, the difference in
wheel speed make direct comparison between the responses measured during tests performed
with the old DAS ( Test 519FD through 533FD) and the new DAS ( 534FD onwards) more
complex, as the time of loading was different.
The stress and strain states in concrete slabs are not only influenced by the induced traffic
loads, but also by other significant factors such as temperature. In order to minimize the effects
of outside temperature, some sections on the North Tangent were conducted with a temperature
control box erected over each section. The target surface temperature was 20 º C and a variation
of ± 7 º C was allowed.
Tests were conducted with the HVS trafficking in either the unidirectional or bi-directional
traffic mode. All tests were performed with a channelized traffic pattern, meaning
that no lateral wander of the test wheel was introduced, and the wheel always traveled along the
25
edge of the slabs next to the asphalt shoulder. Wander was not introduced because it would have
prolonged the time required to achieve fatigue cracking on each test section.
In the case of loading the widened truck lane sections ( Tests 539FD through 541FD), the
HVS loading wheel traveled 0.6 m from the edge of the concrete slab as shown in Figures 10– 12
26
27
4.0 HVS RESULTS
The results of the individual HVS tests are summarized in this section. A previously
published report on the construction of the test sections at Palmdale gives complete details of the
instrumentation layout, which will not be repeated here ( 1). Data collection was undertaken at
various intervals for the various tests and is summarized for each test section. For fatigue
analysis purposes, the appearance of a crack on the middle slab signified fatigue failure. In
certain cases, the HVS tests were run longer to monitor the performance of the middle and
adjacent slabs after the first fatigue crack.
During all tests on the North Tangent, data collection took place with the HVS wheel
traveling in the same direction ( HVS cabin to tow- end direction). Load transfer efficiency ( LTE)
was therefore also calculated with the HVS wheel running only in one direction ( unlike the
South Tangent where LTE was calculated for the wheel running in both directions). LTE values
were calculated using two methods at each joint. Because two JDMDs were placed on either side
of the joint, it was possible to calculate LTE when the HVS wheel is right over the one JDMD
and again when the wheel has crossed the joint and is right over the second JDMD. In the
subsequent tables and graphs, both calculations of LTE are presented.
Because temperature differentials inside the concrete slab significantly affect the stress
and strain state, which in turn influences surface deflections, the temperature difference between
the surface and the bottom of the PCC layer at the time of deflection measurements is also given
with the tabulated deflection data. Thermocouple data collection was not always in
synchronization with regular data collection so in some cases, no data are available.
Because data collection took place at 2- hour intervals, it is not possible to present all the
collected data in table format. The complete data set is available on the HVS database located at
28
The Pavement Research Center at the University of California, Berkeley. The results are,
nevertheless given in graphical format and summary tables are given throughout this report.
To assist in the interpretation of the effects of temperature on the measured responses, all
graphs detailing pavement response data consists of two parts: the top part presents the
thermocouple temperature data and the bottom part the response data.
All temperature graphs show two types of data: the surface temperature on the test pad as
well as the temperature difference ( difference between top and bottom temperature of the 200-
mm PCC sections) at various places as described in Chapter 3.2.3. To improve the clarity of the
temperature data plots, a second vertical axis showing the temperature differential ( top –
bottom), is included on the right hand side of all graphs used in this report.
4.1 Test 532FD
Test 532FD was undertaken on Slabs 42, 43, and 44 on Section 7 of the North Tangent.
Slab 43 ( total length 3.95 m) was fully tested, together with some area on either side of Joints 42
and 43 in Slabs 42 ( total length 5.82 m) and Slab 44 ( total length 3.65 m). In order to minimize
stresses and strains caused by temperature effects, the temperature control chamber was used
during this test. Unidirectional trafficking was applied throughout the test. This was the first of
four tests on Section 7. The section was constructed of 200- mm FSHCC pavement without
dowels and with an asphalt shoulder.
The test was conducted in three phases: Phase I started with a 40- kN dual wheel load and
was kept constant up to 7,794 unidirectional repetitions, as which point loading was paused for
18 hours. While loading was stopped, the joints were saturated with water at a rate of 4.92 l/ hour
per joint. A total of 88.6 l/ joint was poured during this 18- hour period.
29
Phase II resumed loading at 40 kN for another 16,543 repetitions while water continued
to be added at the joints as in Phase I.
Phase III consisted of 177,965 load repetitions with the load increased to 70 kN together
with water being added at the same rate as in Phase I and Phase II. A total of 202,302
unidirectional load repetitions were applied to the section.
4.1.1 Visual Observations
The crack pattern, as it developed with time, can be seen in Figure 13. The figure shows
the outer shoulder at the bottom of the page ( the trailer side). The inner shoulder, near the K- rail
( the opposing traffic side), is at the top of the figure.
Prior to the start of the test, a mid- slab crack existed right through Slab 42 ( See Figure
13). After the first two loading cycles ( Phases I and II), no visible cracks could be found. A
corner crack in Slab 44 ( towards Joint 43) developed after another 20,875 load applications of 70
kN at a total of 45 121 load applications. This crack was immediately followed by a smaller
corner crack on the same slab ( 44) towards Joint 43. The ingress of water had a very detrimental
effect on the support of the slab and visible pumping could be seen at Joint 43. This pumping led
to the complete loss of support under Slab 44 and a huge chunk of concrete broke loose in the
corner of Slab 44. In order not to damage the trafficking wheels, a piece of wood was put in
place where the concrete chunk broke loose. Another corner crack developed in Slab 43 towards
Joint 43. A composite image of the final crack pattern can be seen in Figure 14.
The number of load repetitions at which each crack appeared was not noted but the
sequence was recorded as seen in Figure 13.
30
Figure 13. Schematic of crack pattern, Test 532FD.
Figure 14. Composite image of Test 532FD showing cracks.
31
4.1.2 Joint Deflection Measuring Device ( JDMD) Results
Two Joint Displacement Monitoring Devices ( JDMDs) were placed on either side of
Joint 42 ( the right- hand joint of Slab 43) and one was placed on the edge of Slab 43 at its
midspan ( midway between the two joints). A summary of the peak deflections at the beginning
and end of each loading phase can be seen in Table 5.
Table 5 JDMD Deflections, Test 532FD
Deflection ( mm) Temperature ( º C)
Corner, Joint 42 Corner, Joint 43 Horizontal
Slab 42 Slab 43
Mid- span,
Slab 43 Slab 43 Slab 44 Joint 43
Repetitions
Test
Load
kN JDMD 1 JDMD 2 JDMD 3 JDMD 4 JDMD 5 JDMD 6 Surface
Difference
( top -
bottom)
10–
7,794 40, dry 1.726
1.751
1.606
1.572
0.656
0.527
17.3
15.6
0.6
- 1.5
7,799–
24,337 40, wet 1.683
1.681
1.570
1.169
0.505
0.509
15.4
18.2
- 1.0
- 0.6
24,342–
202,302 70 2.079
1.764
1.273
2.462
0.632
0.585
N/ A N/ A N/ A
17.8
21.4
- 0.9
- 0.4
The data are also graphically displayed in Figure 15. To properly interpret these values,
they should be analyzed together with the crack pattern as displayed in Figure 13.
It seems as if the crack development at Joint 43 ( see Figures 13 and 14) had little effect
on the deflections measured at the other joint ( Joint 42). Even after water was added and the load
increased to 70 kN ( from 40 kN), deflections stayed relatively constant and no sudden increase
was detected.
After 202,302 repetitions, Joint 43 had deteriorated to such an extent that the test was
stopped. However, no instruments were placed at this joint so performance data are not available.
32
Figure 15. Plot of JDMD deflections and temperature versus load repetitions, Test 532FD.
33
4.1.3 Joint Load Transfer Efficiency ( LTE)
The Load Transfer Efficiency ( LTE) was calculated at the left- hand joint of the middle
slab ( Joint 42 between Slab 42 and Slab 43). The joint deterioration with number of load
applications can be seen in Figure 16. Summary results are presented in Table 6.
Table 6 Load Transfer Efficiency, Test 532FD
Load Transfer Efficiency (%) Temperature ( º C)
Corner, Joint 42 Corner, Joint 43
Slab 42 Slab 43 Slab 43 Slab 44
Repetitions
Test
Load,
kN JDMD 1 JDMD 2 JDMD 4 JDMD 5 Surface
Difference
( top –
bottom)
10 – 73.5 69.2
7,794
40,
dry 72.5 53.8
17.3
15.6
0.6
- 1.5
7,799 – 67.7 52.3
24,337
40,
wet 76.8 73.3
15.4
18.2
- 1.0
- 0.6
24,342 – 98.5 97.1
202,302 70 87.5 75.5
N/ A N/ A
17.8
21.4
- 0.9
- 0.4
The reason why the LTE values increased from around 70 percent to 90 percent after
about 24,000 repetitions is not known. One possible reason is the influence of temperature
variations. Although the variations in surface temperature are not substantial ( Figure 16) at the
position where the thermocouple was placed ( see Figure 3), it is possible that more dramatic
temperature changes took place at the joint were the LTE values were calculated. Higher surface
temperatures cause concrete slabs to expand. This expansion can lead to an increased degree of
aggregate interlock as reported by the increased LTE values.
After about 120,000 repetitions, the area in the proximity of Joint 43 had extensive
cracking ( see Figure 13). This crack pattern had an effect on the LTE calculated at the right- hand
side of Joint 42, which is clearly visible in Figure 16.
34
Figure 16. Plot of LTE and temperature versus load repetitions, Test 532FD.
35
The LTE calculated from JDMD 2 was 75.5 percent after 202,302 repetitions compared
to that of JDMD 1 of 87.5 percent after the same number of repetitions. It is obvious that the
extensive cracking at Joint 43 had a significant effect on the LTE measured by JDMD 2. The
reason for this is probably due to the extensive cracking which took place on Slab 44. The LTE
at Joint 43 was obviously reduced to zero after the piece of concrete broke loose, and this had an
effect on the LTE values measured at the other joint ( Joint 42).
4.2 Test 533FD
Test 533FD was the second HVS test performed on the undoweled 200- mm PCC sections
with an asphalt shoulder.
HVS Test Section 533FD was located on Slabs 38, 39, and 40, with the 8 × 1 m test pad
placed in such a way that Slab 39 ( total length 4.03 m) was fully tested along its edge plus some
area from Slab 38 ( total length 5.79 m) and Slab 40 ( total length 3.65 m). The temperature
control chamber was used during this test. The test was completed without the use of water;
trafficking was unidirectional. The test started with a 40- kN dual wheel load, which was kept
constant to 44,164 repetitions, after which it was increased to 70 kN for 210, 003 repetitions. The
test was stopped after another 116,983 loading repetitions at 90 kN, for a total of 371,150
unidirectional load applications.
4.2.1 Visual Observations
Prior to the start of Test 533FD, a cracks existed that ran through the complete width of
the Slab 38 ( 3.66 m) starting 3,707 mm left of Joint 38. The crack pattern that developed with
36
time is shown in Figure 17. A composite image of the completed test section is shown in Figure
18.
No additional cracks developed during the 40- kN or 70- kN loading cycles. The first load-related
crack was detected after 33,631 repetitions of 90- kN loading, which is after a total of
287,798 total load applications. This crack started at Joint 38 about 200 mm outside the
wheelpath and ran parallel to the edge of the slab, towards the existing crack at the start of the
test on Slab 38.
After another 52,789 90- kN load repetitions ( total of 340,587), a second longitudinal
crack developed through the length of Slab 40 between Joints 39 and 40, about 1.5 m away from
the edge. The center slab ( Slab 39) did not crack and testing was stopped after a total of 371,150
unidirectional load applications.
4.2.2 Joint Deflection Measuring Device ( JDMD) Results
Five JDMDs were placed on Section 533FD: on either side of both the joints ( Joints 38
and 39), and on the edge at midpoint of Slab 39 ( Figure 4). The results can be seen in Figure 19
and are summarized in Table 7.
Table 7 JDMD Deflections, Test 533FD
Deflection ( mm) Temperature ( º C)
Corner, Joint 39 Corner, Joint 40 Horizontal
Slab 40 Slab 39
Mid- span,
Slab 39 Slab 39 Slab 38 Joint 39
Repetitions
Test
Load
kN JDMD 1 JDMD 2 JDMD 3 JDMD 4 JDMD 5 JDMD 6 Surface
Difference
( top -
bottom)
10– 17.1 - 2.5
44,164 40 1.282
1.499
1.089
1.472
0.452
0.505
1.345
1.410
1.221
1.368 18.4 - 1.1
44,169– 17.6 - 1.9
254,167 70 2.306
2.036
2.276
2.273
0.721
0.705
2.070
2.264
1.988
2.091 18.4 - 0.7
254,172– 18.0 - 1.1
371,149 90 2.251
2.567
2.557
2.485
0.767
0.807
2.382
2.402
2.189
1.976
N/ A
19.9 - 0.3
37
Figure 17. Schematic of crack pattern, Test 533FD.
Figure 18. Composite image of Test 533FD showing cracks.
38
The surface deflections were very similar at all joints, starting at around 1.2 mm under
the influence of the 40- kN load. This increased to around 1.4 mm at the end of the 40- kN phase.
The increase in deflections from one loading phase to another ( from 40 kN to 70 kN and then
again to 90 kN) is expected because of the increase test load.
From Figure 19, it is clear that the existing crack in Slab 38 had little effect on the
deflections measured in the vicinity of the crack. The deflections on either side of Joint 38 are
not significantly different from those measured at Joint 39 where no cracks existed. The middle
slab ( Slab 39) edge deflections are significantly lower than the corner deflections. This behavior
is expected as these sections were constructed without dowels and the free corners are expected
to exhibit more deflection than the middle of the slab.
Towards the end of the test, the corner deflections measured on Slab 38 ( Joint 38) show a
significant drop, whereas all the other deflections stayed relatively constant for the remainder of
the test. One explanation for this behavior may be the influence of the longitudinal crack that
developed in Slab 38 ( see Figure 17) on the corner deflection of that slab. It is possible that the
corner of the slab was not in full contact with the base course due to differential shrinkage and
warping. After the crack developed the one piece of the slab fully in contacted the base course,
which caused a drop in the corner deflections because of increased support from below.
4.2.3 Joint Load Transfer Efficiency ( LTE)
The Load Transfer Efficiency ( LTE) was calculated at either side of the middle slab
( Joints 38 and 39). The joint deterioration with number of load applications can be seen in Figure
20. Summary results are presented in Table 8.
39
Figure 19. Plot of JDMD deflections and temperature versus load repetitions, Test 533FD.
40
Figure 20. Plot of LTE and temperature versus load repetitions, Test 533FD.
41
Table 8 Load Transfer Efficiency, Test 533FD
Load Transfer Efficiency (%) Temperature ( º C)
Corner, Joint 39 Corner, Joint 38
Slab 40 Slab 39 Slab 39 Slab 38
Repetitions
Test
Load,
kN JDMD 1 JDMD 2 JDMD 4 JDMD 5 Surface
Difference
( top –
bottom)
10 –
44,164 40 76.6
84.2
64.6
78.2
73.0
96.5
82.2
96.0
17.1
18.4
- 2.5
- 1.1
44,169 –
254,167 70 84.9
93.5
82.6
85.8
96.6
92.3
93.8
89.6
17.6
18.4
- 1.9
- 0.7
254,172 –
371,149 90 93.9
86.1
84.1
94.2
91.1
78.5
88.4
73.4
18.0
19.9
- 1.1
- 0.3
Steady rises in LTE values were observed from the beginning of the test until around
150,000 load application. The reason for this behavior is not known; it may be due to the same
reasons as for Test 532 ( Chapter 4.1.3). After 150,000 repetitions, LTE gradually decreased. This
suggests that the load transfer due to aggregate interlock was deteriorating under the influence of
the trafficking load. But even at the end of the test, the LTE values were still high. The only
noticeable drop in LTE values took place at the right hand side of the middle slab at Joint 38.
The crack which developed after 340,000 repetitions caused a drop where values as low as 73
percent were recorded at the end of the test.
4.2.4 Multi- Depth Deflectometer ( MDD) Results
Two MDDs were installed on Test 533FD. MDD 14 and 15 were placed on either side of
Joint 39, one in Slab 39 and the other in Slab 40 ( see Chapter 3.2.2). Each MDD had 4 modules
measuring deflection at depths of 0 mm ( surface), 200 mm, 425 mm and 650 mm. The data
measured by MDD 14 and 15 can be seen in Figures 21 and 22. An abbreviated summary of the
deflections of the upper two modules appears in Table 9.
42
Table 9 MDD Deflections, Test 533FD
Deflection ( mm) Temperature ( º C)
MDD 14, Slab 39 MDD 15, Slab 40
Repetitions
Test
Load,
kN 0 mm 200 mm 0 mm 200 mm Surface
Difference
( top –
bottom)
10 –
44,164 40 0.895
1.036
0.042
0.036
1.130
1.796
0.008
0.118
17.1
18.4
- 2.5
- 1.1
44,169 –
254,167 70 1.515
1.772
0.079
0.112
1.829
1.810
0.120
0.178
17.6
18.4
- 1.9
- 0.7
254,172 –
371,149 90 1.878
1.823
0.135
0.227
1.857
1.823
0.182
0.227
18.0
19.9
- 1.1
- 0.3
The deflections in both slabs show similar trends. The deflections recorded with the
MDDs are, as expected, lower than those recorded with the corner JDMDs. Because the MDDs
were placed approximately 300 mm from the edge of the slab, they are not substantially
influenced by the edge curling effects that cause high corner deflections.
More important is the deflections recorded in the sub- structure. From Table 9 and Figure
21, it is clear that almost all the deflection measured at the surface originated in the concrete
slabs and very little deflection was detected in the base layer. Because concrete is a stiff,
incompressible material, the only logical reason for this observation is that differential shrinkage
created significant slab curling and warping. This curling caused the slabs to loose contact with
the underlying layers, which explains why very little deflection was recorded in the base.
During Test 533FD, temperature control was exercised with the aid of the temperature
control chamber. This is evident by the constant surface temperatures and relatively small
temperature gradient ( no more than – 2 º C, as shown in Figures 21 and 22). Differential shrinkage
after construction probably caused these slabs to be permanently warped upwards along the sides
and edges of the slab. This caused the slabs to lose contact with the base layer along the free
edges of the slabs. From the responses measured by the MDDs it is clear that even with the
43
Figure 21. Plot of MDD 14 deflections and temperature versus load repetitions, Test
533FD.
44
Figure 22. Plot of MDD 15 deflections and temperature versus load repetitions, Test
533FD.
45
application of a 90- kN load, very little deflection occurred in the base layer. This suggests that
even under this high load, the edges of the 200- mm slabs were not in full contact with the base
layer. If the slabs were in full contact with the base, the MDD module placed just below the PCC
slab inside the base layer ( MDD level 2) would have recorded significantly higher deflections.
It is interesting to note that MDD 15, level 2 ( placed in the base under Slab 40) did show
a slight increase in deflections after the development of the longitudinal crack at 340,587
repetitions ( see Figure 22). This crack then caused the slab to have a higher degree of contact
between the bottom of the slab and the base, which in turn caused a subsequent drop in the
surface deflection as recorded by the surface MDD ( Figure 22).
These observations are in agreement with findings from test sections on the South
Tangent as well as an environmental study which was conducted to investigate the influences of
temperature changes on slab curling ( 1,2).
4.3 Test 534FD
Test 534FD was the first test in which the new data acquisition system was used
( discussed in Chapter 3.1). Data was recorded on the fly with the HVS trafficking wheel moving
at a typical speed of about 7 km/ h. Data collection was performed at regular 2- hour intervals on a
24- hour basis. From Test 534FD onwards, trafficking was applied bi- directionally, however, data
collection was only performed when the HVS loading wheel traveled in the cabin- to- tow- end
direction of the HVS.
Trafficking was begun with a 40- kN load for 126,580 repetitions followed by a 70- kN
phase of 858,022 repetitions. The last phase consisted of 299,758 repetitions of a 90- kN load.
The test was stopped after a total of 1,284,360 repetitions.
46
The test was conducted on Slab 34 ( total length 5.91 m), Slab 35 ( total length 3.86 m)
and Slab 36 ( total length 3.90 m). Slab 35 ( the center slab) was fully tested together with some
areas on either side of Joints 34 ( in Slab 34) and 35 ( in Slab 36) ( Figure 5).
4.3.1 Visual Observations
No cracks existed on any of the slabs prior to starting the test. The section stayed intact
for nearly the duration of the whole test. After 1,278,568 repetitions, a corner crack developed in
the middle of the center slab ( Slab 35), about 1,900 mm from Joint 34. The crack started at the
midspan edge of the middle slab immediately to the left of the edge JDMD placed in the middle
of Slab 35. The crack propagated towards Joint 34 and is symmetrically placed around the
outside corner of Slab 35. The final crack pattern can be seen in the schematic of the crack
pattern ( Figure 23) and the composite image of the test section ( Figure 24).
4.3.2 Joint Deflection Measuring Device ( JDMD) Results
Five JDMDs were installed on Section 534FD; all were along the edge of the test pad. A
summary of the most significant results can be seen in Table 10; complete results appear in
Figure 25. Temperatures were only recorded from 1,269,356 repetitions until the end of the test.
Table 10 JDMD Deflections, Test 534FD
Deflection ( mm) Temperature ( º C)
Corner, Joint 35 Corner, Joint 34 Horizontal
Slab 36 Slab 35
Mid- span,
Slab 35 Slab 35 Slab 34 Joint 35
Repetitions
Test
Load
kN JDMD 1 JDMD 2 JDMD 3 JDMD 4 JDMD 5 JDMD 6 Surface
Difference
( top -
bottom)
10 –
126,580 40 1.401
1.451
1.503
1.183
0.635
0.560
1.688
1.412
2.094
1.428
126,628 –
974,602 70 1.802
1.814
1.862
1.817
0.718
0.843
2.071
2.438
2.110
1.947
N/ A N/ A
989,441 –
1,284,360 90 2.190
3.421
1.748
2.857
0.761
1.392
2.312
1.971
1.909
3.726
N/ A
22.7 0.8
47
Figure 23. Schematic of crack pattern, Test 534FD.
Figure 24. Composite image of Test 534FD showing cracks.
48
Figure 25. Plot of JDMD deflections and temperature versus load repetitions ( entire
loading sequence), Test 534FD.
49
The corner and edge deflections values with the 40- kN load are significantly higher than
their counterparts in Test Sections 532FD and 533FD ( compare Table 10 with Tables 7 and 5),
although the slab lengths are almost the same ( see Table 2). One possible explanation for this is
the condition of the test section prior to the start of the test. Tests 532 and 533 had cracks in the
slabs prior to the start of those tests, but the slabs of Test 534FD had no cracks. Differential
shrinkage may have caused slab lift- off and the fact that all these slabs were fully intact may
have caused a higher degree of lift- off along the edges. This would explain why higher initial
deflections were recorded on Test 534FD than on Tests 534FD and 533FD.
As expected, deflections increased with increasing test load. Deflection values as high as
3.2 mm were recorded towards the end of the test.
An important observation is the behavior of the surface deflections just before and after
the crack occurred after about 1.28 million load applications ( see Figure 26). First, the corner
deflections at Joint 34 experienced a significant drop in values from before to after the crack.
Prior to the crack, the deflection measured with the corner JDMD on Slab 35, Joint 34 was
almost 4 mm. After Slab 35 cracked, deflections dropped to 1.2 mm. This relates to a 66 percent
drop in deflection. All the other JDMDs recorded drops in deflections, but not to the same degree
as the corner JDMD at Slab 35.
Second, Figure 26 clearly show that after the crack developed, the deflection readings
recovered somewhat. Deflections did not return to the same level as before the crack appeared. It
is likely that after settlement of the slab and its loose cracked piece, the deflections increased
again due to the heavier ( 90 kN) loading that was applied to the section until the test was
stopped.
50
Figure 26. Plot of JDMD deflections and temperature versus load repetitions ( 1M
repetitions to end of test), Test 534FD.
51
4.3.3 Joint Load Transfer Efficiency ( LTE)
LTE values with repetitions can be seen in Figure 27. The effect of accelerated loading
on the load transfer efficiency is clearly visible. LTE values between 80 and 100 percent were
calculated at the beginning of the test but deterioration of aggregate interlock had a negative
effect the load transfer efficiency.
The high corner deflections ( see Table 10) had a rapid detrimental effect on the aggregate
interlock at the joints. From Figure 27, it is clear that the accelerated loading destroyed the
required aggregate interlock with the resulting drop in load transfer. Toward the end of the test
LTE values less than 20 percent were observed.
4.3.4 Multi- Depth Deflectometer ( MDD) Results
Two MDDs were placed in the vicinity of Joint 35. MDD 12 was placed approximately
300 mm from the joint in Slab 35 ( the center slab). MDD 13 was placed approximately 300 mm
from the joint in Slab 36. The module depths were the same as the MDDs in Test 533FD: at the
surface ( 0 mm), 200 mm, 425 mm and 650 mm.
The MDD data are shown in Figures 28 and 29 and summarized in Table 11 and Table 12
for the deflections and the permanent deformation data, respectively.
Table 11 MDD Deflections, Test 534FD
Deflection ( mm) Temperature ( º C)
MDD 12, Slab 35 MDD 13, Slab 36
Repetitions
Test
Load,
kN 0 mm 200 mm 0 mm 200 mm Surface
Difference
( top –
bottom)
10 –
126,580 40 1.039
1.119
0.058
0.070
1.146
0.960
0.016
0.021 N/ A N/ A
126,628 –
974,602 70 1.341
1.439
0.051
0.060
1.437
1.524
0.018
0.045
984,602 –
1,284,360 90 1.649
2.581
0.253
0.247
1.809
2.085
0.380
0.260 22.7 0.8
52
Figure 27. Plot of LTE and temperature versus load repetitions, Test 534FD.
53
Figure 28. Plot of MDD 12 deflections and temperature versus load repetitions, Test
534FD.
54
Figure 29. Plot of MDD 13 deflections and temperature versus load repetitions, Test
534FD.
55
The deflection values are very similar to those measured during Test 533FD and the
trends are the same. It is clear that for the duration of the test, all the deflections originated from
the PCC layer while very little deflections were recorded in the underlying layers. After the
development of the corner crack in Slab 35, some noticeable deflections were recorded from the
deeper levels in MDD 12 ( placed in the base under Slab 35). These increasing deflections
suggest that the crack in the concrete caused the slab to make contact with the base layer which
then caused deflections in the underlying layers ( see Figure 28).
The permanent deformation data reveal the same result. Figure 30 shows the permanent
deformation data recorded by MDD 12 in Slab 35. The data are summarized in Table 12. The
permanent movement in level 2 ( placed just below the 200- mm concrete layer) had very little
permanent movement until the crack started to develop. Subsequent increase in contact of the
slab on the base layer led to the effects of the loading on the underlying layers, including
deformations measured at MDD 12 level 2.
Table 12 MDD 12 Permanent Deformation, Test 534FD
Permanent Deformation ( mm) Temperature ( º C)
MDD 12, Slab 35
Repetitions
Test
Load,
kN 0 mm 200 mm 425 mm 650 mm Surface
Difference
( top –
bottom)
10 –
126,580 40 0.000
0.971
0.000
0.217
0.000
0.059
0.000
0.000
126,628 –
974,602 70 1.000
1.206
0.217
0.186
0.061
0.059
0.000
0.000
N/ A N/ A
984,602 –
1,284,360 90 1.589
3.411
0.160
0.197
- 0.039
- 0.095
0.000
0.000 22.7 0.8
56
Figure 30. Plot of MDD 12 permanent deformation and temperature versus load
repetitions, Test 534FD.
57
4.4 Test 535FD
Test 535FD was the last test conducted on Section 7 ( slabs with no dowels and with an
asphalt shoulder). Because of the performance of the previous tests, loading started with a 90 kN
wheel load and was stopped after 80,000 load applications. The test was conducted on Slabs 31
( total length 4.11 m), 32 ( the center slab with a total length of 3.71 m) and 33 ( total length 5.35
m).
During this test the new DAS was fully operational and automatically recording of all the
thermocouple, JDMD, and MDD data.
4.4.1 Visual observation
The final crack pattern of Section 535FD is shown in Figure 31. Figure 32 presents a
composite image of the test section after the completion of HVS trafficking.
Before starting the test, a series of cracks existed through the width of Slab 33. These
cracks occurred at midspan approximately 2,700 mm from Joint 32 ( Slab 33 total length 5.35 m).
On Slab 32, the first structural crack appeared after 67,935 load applications. A corner
crack on Slab 32 developed approximately 0.5 m from Joint 32. This crack extended right across
the length of the center slab ( total length = 3.71 m) and ended up at Joint 31 about 1,600 mm
from the edge.
The last crack appeared in Slab 31 at the end of the test after 80,000 repetitions. This was
a corner crack, which started at about mid- span of Slab 31 and ended at Joint 31 in the middle of
Slab 31.
58
Figure 31. Schematic of crack pattern, Test 535FD.
Figure 32. Composite image of Test 535FD showing cracks.
59
4.4.2 Joint Deflection Measuring Device ( JDMD) Results
Six JDMDs were installed for Test 535FD, of which five recorded edge deflections and
one recorded horizontal movements across Joint 32 just outside the trafficking area ( Figure 6).
The summary data can be seen in Table 13 and the complete data set is graphically displayed in
Figure 33.
The upper part of Figure 33 displays the surface temperature ( recorded inside the
temperature control box) as well as the temperature differentials ( temperature at the top of the
concrete layer – the temperature at the bottom) of all the installed thermocouples for the duration
of the test. From the graph, the day- night cyclic effect is clearly visible. The thermocouples
Table 13 JDMD Deflections, Test 535FD
Deflection ( mm) Temperature ( º C)
Corner, Joint 32 Corner, Joint 31 Horizontal
Slab 33 Slab 32
Mid- span,
Slab 32 Slab 32 Slab 31 Joint 33
Repetitions
Test
Load
kN JDMD 1 JDMD 2 JDMD 3 JDMD 4 JDMD 5 JDMD 6 Surface
Difference
( top -
bottom)
0 1.930 2.089 1.048 2.924 2.777 0.072 14.9 - 1.3
11 1.868 2.093 1.036 2.919 2.756 0.074 15.5 - 1.0
101 1.911 2.104 1.094 2.935 2.776 0.071 15.7 - 0.8
502 1.950 2.128 1.066 2.989 2.765 0.073 16.4 - 0.3
1,002 1.923 2.129 1.102 2.989 2.713 0.077 17.0 0.3
2,003 1.867 2.067 1.074 2.934 2.592 0.080 18.2 1.3
3,003 1.852 2.022 1.042 2.849 2.543 0.065 19.6 1.9
4,003 1.940 2.075 1.039 2.885 2.656 0.059 20.3 2.3
5,003 2.072 2.165 1.061 2.956 2.865 0.065 19.5 2.2
6,002 2.160 2.238 1.068 3.043 3.029 0.067 19.0 2.0
7,002 2.202 2.283 1.115 3.055 3.146 0.069 18.4 1.8
8,002 2.246 2.310 1.055 2.993 3.327 0.075 18.0 1.4
9,002 2.261 2.326 1.048 2.932 3.451 0.081 18.4 1.2
10,002 2.270 2.326 1.010 2.890 3.530 0.083 18.8 1.3
11,002 2.265 2.331 1.024 2.864 3.578 0.083 18.9 1.1
12,002 2.248 2.295 0.971 2.742 3.649 0.088 19.6 1.5
13,002 2.219 2.265 0.946 2.607 3.713 0.081 20.4 2.0
14,002 2.190 2.221 0.895 2.550 3.709 0.081 21.9 3.2
15,002 2.148 2.166 0.863 2.466 3.669 0.075 22.2 2.6
20,003 2.264 2.132 0.893 2.463 3.734 0.063 21.7 2.4
30,002 2.166 2.198 1.056 2.873 3.249 0.068 21.3 0.3
40,003 2.392 2.380 1.040 3.038 3.763 0.076 20.1 0.3
50,002 2.464 2.239 1.110 3.143 3.241 0.062 21.0 0.8
60,002 2.468 1.993 1.005 2.889 3.092 0.040 23.2 1.5
70,002 2.191 1.753 0.511 1.392 1.956 0.016 22.5 0.6
80,002
90
2.676 2.199 0.596 1.617 2.305 0.007 20.9 - 0.4
60
90 kN Dry
Loading Sequence:
Longitudinal crack on Slab 32, Joint 31 
appeared after 67,935 repetitions
- 5.0
0.0
5.0
10.0
15.0
20.0
25.0
Temperature ( º C)
Surface
Differential Test Pad
Differential Shade
Differential Sun
Differential K- rail
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000
Uni- directional Repetitions
Deflection ( mm)
Corner Slab 33/ Joint 32 Corner Slab 32/ Joint 32 Mid- span Edge Slab 32
Corner Slab 32/ Joint 31 Corner Slab 31/ Joint 31 Horizontal Joint 32
Figure 33. Plot of JDMD deflections and temperature versus load repetitions, Test 535FD.
61
outside the temperature control box ( TC Sun and TC K- rail) show maximum temperature
differentials of up to 18 º C, whereas the temperature differentials inside temperature control are
lower than 5 º C.
Figure 33 shows an inverse correlation between deflection data and the corresponding
temperature data ( TC Sun, TC Test Pad, TC K- rail, and TC Shade). An increase in temperature
difference leads to a decrease in deflections. One possible explanation for this behavior is that
differential shrinkage, warping, and curling caused the initial position of the slab to be curled
upwards, preventing the slab from full contact with the base. The lack of support from the
underlying layers leads to high deflection values. As the surface temperature increases during the
day, the slab heats up on the surface and expands, causing it to curl downwards. The downward
curl causes the slab to come in contact with the base, which then leads to reduced deflections.
The JDMD deflections started off higher that in previous tests. However, this test started
with a 90- kN load, which was higher than in previous tests. The deflections recorded at Joint 31
were higher than those recorded at the other joint ( Joint 32). The midspan edge deflections were
the lowest of the five measured locations, which is in agreement with all other previous tests.
The corner crack at Joint 31 had a significant influence on the measured deflections at the
same joint. Deflections at this joint prior to the crack were on the order of 3.5 mm; after the
crack developed, they dropped to as low as 1.4 mm. This observation supports the hypothesis
that the slabs along its edges were not in contact with the base course, resulting in initial high
deflections. As in previous tests, once the slab made contact with the base ( after the crack
developed), the measured deflections dropped.
The elastic horizontal movement measured at Joint 31 displayed similar behavior.
Maximum movement on the order of 0.083 mm dropped to 0.02 mm after the crack developed.
62
4.4.3 Joint Load Transfer Efficiency ( LTE)
The LTE is shown in Table 14 and Figure 34. The changes in LTE are somewhat
unexpected. Studying the graph, one would expect the LTE values to drop as aggregate interlock
deteriorates. The LTE values, calculated at the joint where the crack developed, should display a
dramatic drop after the corner crack developed, however according to the data this did not
happen. A likely explanation is that slab rocking caused by irregular edge movements as
indicated by the various JDMDs at the corners of the joints caused the calculation of the LTE
values to be erroneous.
Table 14 Load Transfer Efficiency, Test 535FD
Load Transfer Efficiency (%) Temperature ( º C)
Corner, Joint 32 Corner, Joint 31
Slab 33 Slab 32 Slab 32 Slab 31
Repetitions
Test
Load,
kN JDMD 1 JDMD 2 JDMD 4 JDMD 5 Surface
Difference
( top –
bottom)
0 64.9 62.2 66.2 67.5 14.9 - 1.3
11 63.9 64.9 65.7 65.1 15.5 - 1.0
101 63.3 64.0 68.6 61.9 15.7 - 0.8
502 61.4 63.6 68.2 65.7 16.4 - 0.3
1,002 60.6 67.3 70.6 65.8 17.0 0.3
2,003 60.5 61.7 69.9 68.9 18.2 1.3
3,003 58.7 62.2 66.8 69.7 19.6 1.9
4,003 62.5 67.3 69.8 70.2 20.3 2.3
5,003 67.4 70.7 73.9 69.1 19.5 2.2
6,002 68.3 71.1 68.9 69.7 19.0 2.0
7,002 69.5 72.6 68.7 68.8 18.4 1.8
8,002 70.8 73.3 67.2 69.6 18.0 1.4
9,002 72.4 72.3 66.1 66.6 18.4 1.2
10,002 73.9 76.6 66.3 66.1 18.8 1.3
11,002 75.1 76.0 65.4 67.0 18.9 1.1
12,002 75.7 77.7 63.0 64.4 19.6 1.5
13,002 77.3 80.8 62.6 64.4 20.4 2.0
14,002 78.6 82.5 60.7 64.5 21.9 3.2
15,002 80.2 83.6 59.9 71.1 22.2 2.6
20,003 80.5 82.3 53.0 68.0 21.7 2.4
30,002 71.5 76.8 52.1 56.0 21.3 0.3
40,003 79.6 82.7 47.1 58.4 20.1 0.3
50,002 81.7 82.0 44.9 53.1 21.0 0.8
60,002 83.7 79.8 42.2 57.0 23.2 1.5
70,002 83.2 80.0 52.4 63.7 22.5 0.6
80,002
90
85.6 82.9 51.5 68.2 20.9 - 0.4
63
90 kN Dry
Loading Sequence:
Longitudinal crack on Slab 32, Joint 31 
appeared after 67,935 repetitions
0.00
20.00
40.00
60.00
80.00
100.00
0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000
Uni- directional Repetitions
LTE (%)
Corner Slab 33/ Joint32 Corner Slab 32/ Joint 32
Corner Slab 32/ Joint 31 Corner Slab 31/ Joint 31
- 5.0
0.0
5.0
10.0
15.0
20.0
25.0
Temperature ( º C)
Surface
Differential Test Pad
Differential Shade
Differential Sun
Differential K- rail
Figure 34. Plot of LTE and temperature versus load repetitions, Test 535FD.
64
4.4.4 Multi- Depth Deflectometer ( MDD) Results
Only one MDD ( MDD 11) was installed on this test section. It was placed at the midspan
of the center slab in the middle of the HVS wheelpath ( see Figure 6). Modules were placed at
depths of 0 mm ( at the surface), 200 mm, 425 mm and 650 mm. The MDD values are lower than
those recorded at the other test sections; however, this MDD was at the midspan of the center
slab, away from the joints where high deflections would be expected. MDD data are shown in
Table 15 and graphically presented in Figure 35.
One interesting observation from this data set is the deflections recorded by MDD
modules in the underlying layers. Figure 35 shows that approximately half of the total deflection
measured at the surface originated at a depth of 200 mm. This means a considerable amount of
deflection occurred in the base course.
As expected, a significant drop in surface deflection occurred after the crack at Joint 31
appeared accompanied by increased deflections measured by the level 2 MDD ( 200- mm depth).
The deflections measured at the end of the test ( after 80,000 repetitions) revealed that the
deflection measured at the surface was almost the same as the deflection measured at 200 mm
( 0.59 mm versus 0.51 mm in Table 15). This shows that after the crack appeared, the slab was in
full contact with the base course. As a result almost all the deflection measured at the surface
originated from the underlying layers.
The permanent deformation data from MDD 11 in Table 16 and Figure 36 show the same
pattern. Figure 36 shows that during the first part of the test, almost all permanent deformation
took place above the depth of 425 mm. The top two MDD modules have very similar
movements, suggesting that the bulk of the deformation occurred in the base course between the
depth of 200 mm and 425 mm.
65
Table 15 MDD Deflections, Test 535FD
Deflection ( mm) Temperature ( º C)
MDD 11, Slab 32
Repetitions
Test
Load,
kN 0 mm 200 mm 425 mm 650 mm Surface
Difference
( top –
bottom)
0 0.817 0.363 0.224 0.161 14.9 - 1.3
11 0.817 0.363 0.224 0.161 15.5 - 1.0
101 0.834 0.364 0.220 0.166 15.7 - 0.8
502 0.835 0.378 0.232 0.170 16.4 - 0.3
1,002 0.824 0.394 0.243 0.172 17.0 0.3
2,003 0.803 0.428 0.270 0.176 18.2 1.3
3,003 0.788 0.423 0.277 0.176 19.6 1.9
4,003 0.801 0.419 0.277 0.175 20.3 2.3
5,003 0.807 0.405 0.267 0.165 19.5 2.2
6,002 0.853 0.403 0.262 0.164 19.0 2.0
7,002 0.874 0.388 0.253 0.164 18.4 1.8
8,002 0.888 0.383 0.249 0.161 18.0 1.4
9,002 0.904 0.386 0.248 0.160 18.4 1.2
10,002 0.904 0.375 0.240 0.154 18.8 1.3
11,002 0.904 0.373 0.236 0.155 18.9 1.1
12,002 0.893 0.368 0.236 0.155 19.6 1.5
13,002 0.889 0.366 0.236 0.153 20.4 2.0
14,002 0.881 0.375 0.238 0.162 21.9 3.2
15,002 0.861 0.382 0.229 0.160 22.2 2.6
20,003 0.879 0.394 0.241 0.161 21.7 2.4
30,002 0.953 0.413 0.239 0.178 21.3 0.3
40,003 1.014 0.371 0.239 0.161 20.1 0.3
50,002 0.966 0.384 0.255 0.162 21.0 0.8
60,002 0.866 0.402 0.251 0.172 23.2 1.5
70,002 0.531 0.470 0.332 0.221 22.5 0.6
80,002
90
0.593 0.513 0.403 0.251 20.9 - 0.4
66
90 kN Dry
Loading Sequence:
Longitudinal crack on Slab 32, Joint 31 
appeared after 67,935 repetitions
0.000
0.200
0.400
0.600
0.800
1.000
1.200
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Uni- directional Repetitions
Deflection ( mm)
Surface 200mm 425mm 650mm
- 5.0
0.0
5.0
10.0
15.0
20.0
25.0
Temperature ( º C)
Surface
Differential Test Pad
Differential Shade
Differential Sun
Differential K- rail
Figure 35. Plot of MDD 11 deflections and temperature versus load repetitions, Test
535FD.
67
Table 16 MDD Permanent Deformation, Test 535FD
Deflection ( mm) Temperature ( º C)
MDD 11, Slab 32
Repetitions
Test
Load,
kN 0 mm 200 mm 425 mm 650 mm Surface
Difference
( top –
bottom)
0 0.000 0.000 0.000 0.000 14.9 - 1.3
11 0.002 0.002 - 0.002 - 0.001 15.5 - 1.0
101 0.012 0.022 0.005 0.005 15.7 - 0.8
502 0.073 0.044 0.001 0.011 16.4 - 0.3
1,002 0.142 0.071 0.010 0.017 17.0 0.3
2,003 0.281 0.141 0.032 0.039 18.2 1.3
3,003 0.370 0.180 0.041 0.051 19.6 1.9
4,003 0.404 0.193 0.050 0.056 20.3 2.3
5,003 0.406 0.208 0.053 0.049 19.5 2.2
6,002 0.381 0.227 0.052 0.043 19.0 2.0
7,002 0.375 0.246 0.061 0.037 18.4 1.8
8,002 0.369 0.239 0.059 0.034 18.0 1.4
9,002 0.365 0.254 0.062 0.029 18.4 1.2
10,002 0.375 0.271 0.064 0.029 18.8 1.3
11,002 0.380 0.268 0.067 0.028 18.9 1.1
12,002 0.405 0.281 0.072 0.029 19.6 1.5
13,002 0.427 0.296 0.078 0.033 20.4 2.0
14,002 0.454 0.303 0.081 0.031 21.9 3.2
15,002 0.484 0.308 0.085 0.030 22.2 2.6
20,003 0.565 0.370 0.116 0.060 21.7 2.4
30,002 0.609 0.430 0.132 0.067 21.3 0.3
40,003 0.591 0.485 0.139 0.043 20.1 0.3
50,002 0.727 0.544 0.173 0.055 21.0 0.8
60,002 0.928 0.622 0.231 0.091 23.2 1.5
70,002 1.873 1.089 0.466 0.207 22.5 0.6
80,002
90
1.957 1.150 0.462 0.171 20.9 - 0.4
68
90 kN Dry
Loading Sequence:
Longitudinal crack on Slab 32, Joint 31
appeared after 67,935 repetitions
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
2.000
2.200
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Uni- directional Repetitions
Deflection ( mm)
Surface 200mm 425mm 650mm
- 5.0
0.0
5.0
10.0
15.0
20.0
25.0
Temperature ( º C)
Surface
Differential Test Pad
Differential Shade
Differential Sun
Differential K- rail
Figure 36. Plot of MDD 11 permanent deformation and temperature versus load
repetitions, Test 535FD.
69
It also can be concluded that although the crack wasn’t observed until after 67,000
repetitions, the effect of the crack can already be seen after 60,000 repetitions. After 60,000
repetitions, the rate of permanent deformation recorded by the surface and the 200- mm deep
modules show a significant increase. This means that structurally, the crack already existed from
60,000 repetitions onward but was only visually detected on the surface at 67,000 repetitions. As
expected, the permanent deformation increased significantly after the crack appeared. The total
permanent deformation at the surface was 2.0 mm at the end of the test, after 80,000 load
applications.
4.5 Test 536FD
HVS Test 536FD was the first of the series of three HVS tests on the 200- mm FSHCC
slabs with dowels and a tied concrete shoulder. Testing proceeded from April 7 to June 12, 2000.
The other two HVS tests in the series are 537FD and 538FD and are reported in Chapters 4.6 and
4.7.
The main objective of this series of tests was to evaluate the influence of various factors,
including slab length and load transfer devices ( dowels), on the effectiveness of joint load
transfer and joint deterioration under repetitive loading and controlled temperature. The fatigue
behavior of the Fast Setting Hydraulic Cement Concrete ( FSHCC) slabs in this series of three
tests was monitored under bi- directional wheel loadings of at least 90 kN and in dry conditions
( no water added).
Test 536FD was conducted on Slabs 26, 27, and 28 so that the full length ( 3.96 m) of
Slab 27 and approximately 2 m on each of the adjacent slabs ( Slabs 26 and 28) was trafficked
( Figure 7). Initially, approximately 750,000 wheel load repetitions were applied with a 90- kN
70
dual wheel. An aircraft tire was then fitted and about 500 repetitions were applied at each of a
series of increasing loads ( 70, 90, 110 and 130 kN). An additional 88,000 repetitions of a 150- kN
( still with temperature control) load were then applied. Following this sequence, a final 150,000
repetitions at the same 150- kN wheel load were applied under ambient temperature. A total of
almost one million channelized wheel load repetitions were applied in this test.
4.5.1 Visual Observations
No cracks were observed throughout Test 536FD and no visible changes in condition
were reported. This is in keeping with a strong, well restrained, pavement slab configuration that
was able to carry almost a million repetitions of heavily overloaded wheel loads ( 90 and 150 kN
for just over 990,000 repetitions of the total number of load repetitions) prior to stopping the test.
Figure 37 shows a composite image of the section.
Figure 37. Composite image of Test 536FD.
71
4.5.2 Joint Deflection Measuring Device ( JDMD) Results
4.5.2.1 Elastic deflections and trafficking
Figures 38– 40 present the elastic deflection data for the test. These three figures
corresponds with three stages of trafficking: the initial 750,000 repetitions at the 90- kN dual
wheel load; the next 2,000 repetitions with aircraft wheel loads increasing from 70 to 130 kN;
and the final 240,000 repetitions with a 150- kN aircraft wheel load. These figures also show the
test slab surface temperatures and the temperature differentials between slab top and bottom at
four locations around the test area. The expanded scale helps examine the data and evaluate
changes throughout each stage of the test.
Deflections cannot be compared directly because measurements were recorded at the
trafficking wheel load, rather than at a selected standard wheel load ( normally 40 kN as the
equivalent standard axle load). All the joint measurements fluctuate considerably and show a
similar distinct “ saw- tooth” variation in values rather than smooth gradual changes. Temperature
fluctuations would seem to be a contributing factor but, before examining this more closely, the
effect of trafficking will be evaluated.
Figure 41 shows deflections recorded by JDMDs 1, 2, 4 and 5 versus trafficking history.
The figure shows deflections recorded on either side of Joints 27 and 26 at each end of Slab 27.
The graphs show the vario