SENSITIVITY ANALYSIS OF AASHTO'S 2002 FLEXIBLE AND RIGID PAVEMENT DESIGN ...

224 Pages·2006·1.6 MB·English

SENSITIVITY ANALYSIS OF AASHTO’S 2002 FLEXIBLE AND RIGID PAVEMENT
DESIGN METHODS

by

SANJAY SHAHJI
B.E. Mumbai University, 2002

A thesis submitted in partial fulfillment of the requirements
for the degree of Master of Science
in the Department of Civil & Environmental Engineering
in the College of Engineering and Computer Science
at the University of Central Florida
Orlando, Florida

Spring Term
2006
© 2006 Sanjay Shahji

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ABSTRACT
Over the years pavement design has been based on empirical equations developed from
the American Association of State Highway Transportation Officials (AASHTO) road tests. The
various editions of the AASHTO pavement design guide have served well for several decades;
nevertheless many serious limitations existed for their continued use as the nation’s primary
pavement design procedure. For example, the traffic loads and truck sizes have increased over
the years, the AASHTO design equations were derived based on the climatic conditions present
at the Road Tests site, and the issue of aging materials was not addressed in the design.
To overcome these limitations AASHTO finally proposed the AASHTO 2002 design
guide which is based on mechanistic – empirical approach and serves to address the
shortcomings and limitations of the earlier empirical design equations developed from the Road
Tests.
In this report, sensitivity analyses were conducted of the new AASHTO 2002 method for
both flexible and rigid pavements, to understand its performance with respect to the various
design parameters. Several important design parameters were selected and were varied one at a
time and their effect on the pavement distresses was found. The sensitivity analysis included
different amount of traffic loads, base materials, base material thicknesses, surface/slab layer
thicknesses and subgrade materials. Some of the illogical results obtained from the sensitivity
analyses were also addressed.
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ACKNOWLEDGMENTS
The writer wishes to express his sincere appreciation and gratitude to his major advisor,
Dr. Shiou-San Kuo, for his guidance and assistance during investigation and preparation of this
research report and for his constant inspiration throughout the graduate program. Special thanks
to the other members of the writer’s guidance committee – Dr. Manoj Chopra and Dr. Hesham
Mahgoub.
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TABLE OF CONTENTS
LIST OF FIGURES.....................................................................................................................viii
LIST OF TABLES.......................................................................................................................xiii
CHAPTER ONE: INTRODUCTION.............................................................................................1
1.1 Problem Statement................................................................................................................1
1.2 Thesis Organisation..............................................................................................................2
1.3 Objective...............................................................................................................................3
CHAPTER TWO: LITERATURE REVIEW.................................................................................4
2.1 Introduction...........................................................................................................................4
2.2 AASHTO Design Equations.................................................................................................5
2.2.1 Original AASHTO Design Equations for flexible pavements.......................................6
2.2.2 Original AASHTO Design Equations for Rigid pavements..........................................8
2.3 Need for Mechanistic- Empirical Design...........................................................................10
2.4 2002 Mechanistic Empirical Design Models......................................................................11
2.4.1 Models for flexible pavement distresses......................................................................12
2.4.1.1 Permanent Deformation in Asphalt mixtures.......................................................12
2.4.1.2 Permanent Deformation in Unbound Materials...................................................14
2.4.1.3 Permanent Déformation of Total Pavement Structure.........................................17
2.4.1.4 Fatigue Cracking in Asphalt Mixtures..................................................................18
2.4.2 Models for Rigid Pavement Distresses........................................................................21
2.4.2.1 JPCP Cracking Model..........................................................................................21
2.4.2.2 JPCP Faulting Model...........................................................................................22
2.4.2.3 CRCP Punchout Model.........................................................................................24
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CHAPTER THREE: AASHTO 2002 DESIGN METHODOLOGY...........................................27
3.1 Introduction.........................................................................................................................27
3.2 Pavement Design Components...........................................................................................28
3.2.1 Design Inputs...............................................................................................................28
3.2.2 Processing of inputs over design analysis period........................................................29
3.2.3 Pavement Response Model..........................................................................................30
3.2.4 Incremental Distress and Damage accumulation.........................................................30
3.2.5 Distress Prediction.......................................................................................................31
3.2.5.1 International Roughness Index (IRI)...................................................................31
3.2.5.2 Bottom-up Fatigue cracking or Alligator cracking..............................................32
3.2.5.3 Surface-down fatigue cracking or Longitudinal Cracking...................................33
3.2.5.4 Thermal Cracking.................................................................................................34
3.2.5.5 Permanent Deformation........................................................................................34
3.2.5.6 Joint Faulting for JPCP........................................................................................35
3.2.5.7 Transverse Slab Cracking in JPCP......................................................................35
3.2.5.8 Punchouts in CRCP..............................................................................................36
3.2.6 Design Reliability:.......................................................................................................36
CHAPTER FOUR: RESULTS OF SENSITIVITY ANALYSIS.................................................37
4.1 Flexible Pavement Sensitivity Analysis..............................................................................37
4.2 Rigid Pavement Sensitivity Analysis................................................................................101
4.2.1 Jointed Plain Concrete Pavement (JPCP)..................................................................101
4.2.2 Continuous Reinforced Concrete Pavement (CRCP)................................................135
CHAPTER FIVE: COMPARISON OF METHODS..................................................................152
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CHAPTER SIX: SUMMARY OF RESULT AND CONCLUSION.........................................156
6.1 Flexible Pavements...........................................................................................................156
6.1.1 Tabulated Results.......................................................................................................156
6.1.2 Conclusions on Flexible Pavement............................................................................159
6.2 Rigid Pavements...............................................................................................................162
6.2.1 Tabulated Results (Jointed Plain Concrete Pavement)..............................................162
6.2.2 Conclusions on Jointed Plain Concrete Pavement (JPCP)........................................165
6.2.3 Tabulated Results (Continuous Reinforced Concrete Pavement)..............................166
6.2.4 Conclusions on Continuous Reinforced Concrete Pavement (CRCP)......................167
APPENDIX: AASHTO 2002 SOFTWARE OUTPUT FOR FLEXIBLE PAVEMENT
EXAMPLE..................................................................................................................................169
LIST OF REFERENCES............................................................................................................210
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LIST OF FIGURES
Figure 1: Terminal IRI vs AADTT...............................................................................................42
Figure 2: AC surface down cracking vs AADTT.........................................................................43
Figure 3: AC bottom up cracking vs AADTT..............................................................................44
Figure 4: AC Thermal Fracture vs AADTT.................................................................................45
Figure 5: Permanent Deformation (AC only) vs AADTT............................................................46
Figure 6: Permanent Deformation (Total Pavement) vs AADTT................................................47
Figure 7: Permanent Deformation in different pavement layers over the design life...................48
Figure 8: Terminal IRI vs AC Layer Thickness..........................................................................49
Figure 9: AC Surface down cracking vs AC Layer Thickness.....................................................50
Figure 10: AC bottom up cracking vs AC layer thickness...........................................................51
Figure 11: AC thermal fracture vs Asphalt Layer thickness.........................................................52
Figure 12: Permanent Deformation (AC only) vs Asphalt Layer Thickness................................53
Figure 13: Permanent Deformation (Total Pavement) vs AC layer thickness..............................54
Figure 14: Terminal IRI vs Base layer thickness..........................................................................55
Figure 15: AC surface down cracking vs Base layer thickness....................................................56
Figure 16: AC bottom up cracking vs Base layer thickness.........................................................57
Figure 17: AC thermal fracture vs Base layer thickness...............................................................58
Figure 18: Permanent Deformation (AC only) vs Base layer thickness.......................................59
Figure 19: Permanent deformation (total) pavement vs Base Layer thickness............................60
Figure 20: Terminal IRI vs Base layer modulus...........................................................................61
Figure 21: AC surface down cracking vs Base layer modulus.....................................................62
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Figure 22:AC bottom up cracking vs Base layer modulus...........................................................63
Figure 23: AC thermal fracture vs Base layer modulus................................................................64
Figure 24: Permanent Deformation (AC only) vs Base layer modulus........................................65
Figure 25: Permanent deformation (Total Pavement) vs Base layer modulus.............................66
Figure 26: Terminal IRI vs Subbase thickness.............................................................................67
Figure 27: AC surface down cracking vs Subbase layer thickness..............................................68
Figure 28:AC bottom up cracking vs Subbase layer thickness.....................................................69
Figure 29:AC thermal fracture vs Subbase layer thickness..........................................................70
Figure 30: Permanent deformation (AC only) vs Subbase layer thickness..................................71
Figure 31: Permanent deformation (Total Pavement) vs Subbase layer thickness.......................72
Figure 32: Terminal IRI vs Subbase layer modulus.....................................................................73
Figure 33: AC surface down cracking vs Subbase layer modulus................................................74
Figure 34: AC bottom up cracking vs Subbase layer modulus.....................................................76
Figure 35: AC thermal fracture vs Subbase layer thickness.........................................................77
Figure 36: Permanent deformation (AC only) vs Subbase layer Modulus...................................78
Figure 37: Permanent deformation (Total Pavement) vs Subbase layer thickness.......................79
Figure 38: Terminal IRI vs Subgrade modulus.............................................................................80
Figure 39: AC surface down cracking vs Subgrade Modulus......................................................81
Figure 40: AC bottom up cracking vs Subgrade modulus............................................................82
Figure 41: AC thermal fracture vs Subgrade modulus.................................................................83
Figure 42: Permanent deformation (AC only) vs Subgrade modulus...........................................84
Figure 43: Permanent deformation vs Subgrade modulus...........................................................85
Figure 44: Sensitivity of Total pavement rutting to Asphalt layer thickeness..............................86
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Figure 45: Sensitivity of Total Pavement Rutting with Base thickness........................................87
Figure 46: Sensitivity of total pavement rutting with the subbase thickness................................88
Figure 47: Sensitivity of Terminal IRI with AC layer thickness..................................................89
Figure 48: Sensitivity of Surface down cracking with Asphalt layer thickness...........................90
Figure 49: Sensitivity of Bottom up cracking vs Asphalt thickness.............................................91
Figure 50: Sensitivity of AC layer rutting with AC layer thickness.............................................92
Figure 51: Sensitivity of Terminal IRI with base layer thickness................................................93
Figure 52: Sensitivity of Bottom up cracking with base layer thickness......................................94
Figure 53: Sensitivity of AC rut with base layer thickness..........................................................95
Figure 54: Terminal IRI vs AC layer thickness ( for Subgrade Modulus of 5k psi and 10k psi).96
Figure 55: AC surface down cracking vs AC layer thickness ( for subgrade modulus of 5k and
10k psi)..................................................................................................................................97
Figure 56: AC bottom up cracking vs AC layer thickness ( for subgrade modulus of 5k and 10k
psi).........................................................................................................................................98
Figure 57: Permanent deformation (AC only) vs AC layer thickness ( for subgrade modululs of
5k and 10k psi)......................................................................................................................99
Figure 58: Perm. Deformation (Total Pavement) vs AC layer thickness ( for subgrade modulus
of 5k and 10k psi)...............................................................................................................100
Figure 59: Sensitivity of Terminal IRI with AADTT.................................................................105
Figure 60: Sensitivity of Transverse Cracking with AADTT.....................................................106
Figure 61: Sensitivity of Mean Joint Faulting with AADTT......................................................107
Figure 62: Sensitivity of Terminal IRI with Slab thickness.......................................................108
Figure 63: Sensitivity of Transverse Cracking with Slab Thickness..........................................109
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