The Future of Asphalt The Future of Asphalt Pavement Structural & Pavement Structural &
Mixture DesignMixture DesignComplex Modulus, E* Complex Modulus, E* ΦΦDynamic Modulus, |E*|Dynamic Modulus, |E*|
Thomas HarmanThomas HarmanAsphalt Pavement Team Leader, R&DAsphalt Pavement Team Leader, R&DFederal Highway AdministrationFederal Highway Administration
www.TFHRC.www.TFHRC.govgov
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I N D U S T R YSUPERPAVE 2005
Materials
Structural
Construction
FutureFuture
PRS / Warranty
2002 Guide
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O F H W
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I N D U S T R YSUPERPAVE 2005Superpave II
The PlayersThe Players
NCHRP 1NCHRP 1--37A37A�� Recommend Test(s)Recommend Test(s)
SPRSPR--0003(84)0003(84)�� E* Pooled FundE* Pooled Fund�� Evaluate Test Evaluate Test
ProceduresProcedures
NCHRP 9NCHRP 9--1919�� Recommend Test(s)Recommend Test(s)
NCHRP 9NCHRP 9--2929�� Equipment SpecsEquipment Specs�� First Articles First Articles EvalEval�� Revise SpecsRevise Specs
2002 Guide
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O F H W
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I N D U S T R YSUPERPAVE 2005Superpave II
Simple Performance Test for Simple Performance Test for Superpave Mix DesignSuperpave Mix Design
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
SPT What Is It?SPT What Is It?
Test(s) that indicates how mix will Test(s) that indicates how mix will performperform�� RuttingRutting�� Cracking Cracking
SPTSPTRequirementsRequirements
�� Absolute Requirements of TestAbsolute Requirements of Test�� Compliment Superpave Volumetric DesignCompliment Superpave Volumetric Design�� Use Gyratory SpecimensUse Gyratory Specimens�� High Correlation to Rutting/FractureHigh Correlation to Rutting/Fracture�� Identify Inferior MixesIdentify Inferior Mixes
�� Preferred Requirements of TestPreferred Requirements of Test�� Tied to Structural Design Tied to Structural Design �� Adaptable to QC/QAAdaptable to QC/QA
Project 9Project 9--19 19 Candidate TestsCandidate Tests
�� Dynamic Modulus, |E*|Dynamic Modulus, |E*|�� RuttingRutting�� CrackingCracking
�� Creep Test, FTCreep Test, FT�� RuttingRutting
�� Repeated Load Test, FNRepeated Load Test, FN�� RuttingRutting
Complex Modulus, E*Complex Modulus, E*
�� Complex Modulus, E* Complex Modulus, E* ΦΦ�� E* =E* = Peak Stress, Peak Stress, σσ
Peak Strain, Peak Strain, ЄЄ
�� VariablesVariables�� TemperatureTemperature�� Frequency (Hz: cycles/second)Frequency (Hz: cycles/second)�� Stress/Strain levelStress/Strain level
Complex Modulus, E* = Complex Modulus, E* = σσ // ЄЄ
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
1.0000 1.0500 1.1000 1.1500 1.2000
Time, seconds
App
lied
Str
ess,
M P
a
0.000000
0.000050
0.000100
0.000150
Res
pons
e S
trai
n, m
m/m
m
StressStrainMax StrainMin Strain
Φ, phase angle
Complex Modulus, E* Complex Modulus, E* ΦΦComplex Modulus, E*
0
500
1000
1500
0 500 1000 1500
Storage Modulus, E' (MPa)
Loss
Mod
ulus
, E"
(MPa
)
Φ, phase angle
E� = |E*|sin ΦE� = |E*|cos Φ
ModulusModulus
�� Complex Modulus,Complex Modulus, E*E*�� Phase Angle, Phase Angle, ΦΦ�� Storage Modulus, Storage Modulus, EE�� = |E*| = |E*| coscos ΦΦ�� Loss Modulus, Loss Modulus, EE�� = |E*| sin = |E*| sin ΦΦ�� Dynamic Modulus, Dynamic Modulus, |E*||E*|
�� VariablesVariables�� TemperatureTemperature�� Frequency (Hz: cycles/second)Frequency (Hz: cycles/second)�� Stress/Strain levelStress/Strain level
Project 9Project 9--19 19 Correlation StudyCorrelation Study
MnRoadMnRoadMnRoadMnRoad
WesTrackWesTrackWesTrackWesTrack FHWAFHWAFHWAFHWA----ALFALFALFALF
ALF: Rut Depth vs. E*max/sinφφφφ @ 130 °F (54.4 °C)
Se/Sy = 0.35R2=0.90
0
10
20
30
40
50
60
0 0.05 0.1 0.15 0.2 0.25
E*max/sinφφφφ (10^6 psi)
Rut D
epth
@ 1
0,00
0 P
asse
s (m
m)
5 - AC-107 - Styrelf8 - Novophalt9 - AC-510 - AC-2011 - Base AC-512 - Base AC-20
Unconfined -- Linear Range
Dynamic Modulus, |E*|Dynamic Modulus, |E*|
0
0*εσ=E
Stress
Strain
Time
�� RuttingRutting�� Min |E*| at High TempMin |E*| at High Temp
�� Fatigue CrackingFatigue Cracking�� Max |E*| at Intermediate TempMax |E*| at Intermediate Temp
Creep Flow Time, FTCreep Flow Time, FT
STR
AI N
Flow Time
TIMEST
RES
S
�� RuttingRutting�� Min FT at High TempMin FT at High Temp
Repeated Load Permanent Repeated Load Permanent Deformation Test, Flow NumberDeformation Test, Flow Number
�� RuttingRutting�� Min FN at High TempMin FN at High Temp
STR
AI N
Flow Number
TIMEST
RES
S
AAdvantagesdvantages
�� Dynamic Modulus, |E*|Dynamic Modulus, |E*|�� Used for Structural Design in 2002 PDGUsed for Structural Design in 2002 PDG�� Addresses Rutting and Cracking Addresses Rutting and Cracking
�� Creep, FTCreep, FT�� Simple Test EquipmentSimple Test Equipment�� Minimal TrainingMinimal Training
�� Repeated Load, FNRepeated Load, FN�� Potentially Best Simulation of Actual LoadingPotentially Best Simulation of Actual Loading
DDisadvantageisadvantage
�� Specimen SizeSpecimen Size�� 1:1.5 D/H Ratio required to ensure 1:1.5 D/H Ratio required to ensure
fundamental propertiesfundamental properties�� 100 mm Diameter by 150 mm High100 mm Diameter by 150 mm High�� Smooth Parallel Ends (Sawed)Smooth Parallel Ends (Sawed)
�� Sawed and Cored From OverSawed and Cored From Over--Height Gyratory SpecimensHeight Gyratory Specimens�� Not all SGC can produced Not all SGC can produced
SpecimensSpecimens
Project 9Project 9--19 19 SPT Criteria DevelopmentSPT Criteria Development
�� Use Models proposed in 1Use Models proposed in 1--37A, account for:37A, account for:�� ClimateClimate�� Traffic LevelTraffic Level�� StructureStructure
�� Test at Effective Pavement TemperatureTest at Effective Pavement Temperature�� Minimum or Maximum ValuesMinimum or Maximum Values
�� Traffic LevelTraffic Level�� Pavement StructurePavement Structure
�� Completed in Fall 2002Completed in Fall 2002
Project 9Project 9--19 Validation19 Validation
�� Criteria Will Be ValidatedCriteria Will Be Validated�� Not the testsNot the tests
�� InIn--Service Pavement DataService Pavement Data�� 50+ LTPP and Other Test 50+ LTPP and Other Test
SectionsSections
�� Completed in 2002Completed in 2002
Project 9Project 9--2929Equipment SpecificationsEquipment Specifications
�� Simple Performance Test SystemSimple Performance Test System�� All 3 TestsAll 3 Tests
�� Automated Specimen Fabrication Equipment�Automated Specimen Fabrication Equipment�
�� Encourage Innovation by ManufacturersEncourage Innovation by Manufacturers�� User FriendlinessUser Friendliness�� ReliabilityReliability�� CostCost
Project 9Project 9--29 29 Specification DevelopmentSpecification Development
Draft Equipment SpecsCost Estimate
Manufacturer’s Review
First Article Equipment SpecsRevised Estimate
User’s Workshop Ideas
Research Test Protocols
First Article SPTFirst Article SPTProcurementProcurement
�� EnduraTecEnduraTec�� InstronInstron�� InterlakenInterlaken�� ShedworksShedworks
• Specifications• Advantages• Cost• Past Performance
First Article SPT SystemsFirst Article SPT Systems
�� TestsTests�� Complex ModulusComplex Modulus�� Flow TimeFlow Time�� Flow NumberFlow Number
�� Temperature RangeTemperature Range�� 20 to 60 °C20 to 60 °C
�� Confining Pressure RangeConfining Pressure Range�� 0 to 210 kPa0 to 210 kPa
First Article First Article Simple Performance Test SystemsSimple Performance Test Systems
SHEDWORKS
INTERLAKEN
InstrumentationInstrumentationLVDT�sLVDT�s
ShedworksShedworks
InterlakenInterlaken
Specimen Fabrication SystemSpecimen Fabrication System
�� Pine Pine �� ShedworksShedworks • Specifications
• Automated• Cost
First Article First Article Specimen Fabrication SystemSpecimen Fabrication System
First Article First Article Specimen Fabrication EquipmentSpecimen Fabrication Equipment
CORE BARREL
BLADES
CHUCK
SummarySummary-- Simple Performance Test Simple Performance Test Work CompletedWork Completed
�� Three Candidate TestsThree Candidate Tests�� Detailed Draft ProtocolsDetailed Draft Protocols�� Detailed Equipment SpecificationsDetailed Equipment Specifications�� First Article DevicesFirst Article Devices
�� Simple Performance Test System Simple Performance Test System ($25 k to $45 k)($25 k to $45 k)
�� Automated Specimen Fabrication System Automated Specimen Fabrication System ($12 k)($12 k)
NCHRP 9NCHRP 9--2929TimelineTimeline
�� Criteria DevelopmentCriteria Development�� Early Fall 2002Early Fall 2002
�� Criteria ValidationCriteria Validation�� End of 2002End of 2002
�� First Article EvaluationFirst Article Evaluation�� Early 2003Early 2003
Dynamic Modulus, |E*| for Dynamic Modulus, |E*| for Structural DesignStructural Design
-80
-70
-60
-50
-40
-30
-20
-10
0
Time (sec.)
Stre
ss (k
Pa)
25 Hz, 68.90 kPa, 200 Cycles
10 Hz, 62.01 kPa, 200 Cycles
5 Hz, 55.12 kPa, 100 Cycles
1 Hz, 48.23 kPa, 50 Cycles
0.5 Hz, 42.34 kPa, 20 Cycles
0.1 Hz, 34.45 kPa, 20 Cycles
180 seconds rest period between frequencies
2002 PDG Requires a 2002 PDG Requires a Range of Frequencies & Temp.�sRange of Frequencies & Temp.�s
10
-70
-60
-50
-40
-30
-20
-10
0398 398.1 398.2 398.3 398.4 398.5 398.6 398.7 398.8
Time (sec.)
Stre
ss (k
Pa)
ExampleExample10 Hz and 62 10 Hz and 62 kPakPa
|E*| Pooled Fund Study |E*| Pooled Fund Study ��UConnUConn (2002 PDG)� (2002 PDG)�
Perliminary Result of Round Robin Study
100
1000
10000
25 10 5 1 0.5 0.1 25 10 5 1 0.5 0.1 25 10 5 1 0.5 0.1
Frequency, Hz
/E*/
, MP
a
MDNCAATFHWA
21°C
38° C
54° C
Understanding Modified BindersUnderstanding Modified BindersNCHRP 90NCHRP 90--07, TPF 5(019)07, TPF 5(019)
FHWAFHWA--ALF ALF Mean and Standard Deviation of |E*|Mean and Standard Deviation of |E*|
(3 Replicates, 50(3 Replicates, 50°°C, 10 Hz)C, 10 Hz)
0200400600800
10001200140016001800
EVACMCRA
ESLSBS L
Air BlownEVAG
PG 70-22
SBS RG
SBS LGElva
loyPG 64
-28|E
*|, M
Pa
MeanStd
FHWAFHWA--ALFALFCoefficient of Variation of |E*|Coefficient of Variation of |E*|
(3 Replicates, 50(3 Replicates, 50°°C, 10 Hz)C, 10 Hz)
0.005.00
10.0015.0020.0025.0030.0035.00
EVACMCRA
ESLSBS L
Air BlownEVAG
PG 70-22
SBS RG
SBS LGElva
loyPG 64
-28
%C
V
TRB Superpave TRB Superpave Binder Expert Task GroupBinder Expert Task Group
!! |E*| Concern|E*| Concern
AASHTO/ TRB / NCHRP / FHWA
Modulus TestingModulus Testing
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
1.0000 1.0500 1.1000 1.1500 1.2000
Time, seconds
App
lied
Str
ess,
M P
a
0.000000
0.000050
0.000100
0.000150
Res
pons
e S
trai
n, m
m/m
m
StressStrainMax StrainMin Strain
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
1.0000 1.0500 1.1000 1.1500 1.2000
Time, seconds
App
lied
Str
ess,
M P
a
0.000000
0.000050
0.000100
0.000150
Res
pons
e S
trai
n, m
m/m
m
StressStrainMax StrainMin Strain
Permanent StrainPermanent Strain
Permanent StrainPermanent Strain
0
20
40
60
80
100
120
140
0.000000 0.000500 0.001000 0.001500
Strain
Str
ess
Fully ElasticPermanent Strain
Allowable Permanent StrainAllowable Permanent Strain
�� VariablesVariables�� Temperature, 21 38 54Temperature, 21 38 54°°CC�� Frequency, 25 10 5 1 .5 .1 HzFrequency, 25 10 5 1 .5 .1 Hz�� Strain level, 50 to 150 Strain level, 50 to 150 µµєє�� Allowable permanent strain, 1000 Allowable permanent strain, 1000 µµєє
�� You can You can notnot controlcontrolpermanent strainpermanent strain
0
20
40
60
80
100
120
140
0.000000 0.000500 0.001000 0.001500
Strain
Str
ess
Fully ElasticPermanent Strain
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
Elvaloy PG64 SBS L SBSLG
PG70 AB SBSRG
EVA G ESI CRA EVA
Dyn
amic
Mod
ulus
, IE*
I, G
Pa
Lab Mix Lab Mix �� Similar PG GradeSimilar PG Grade|E*| at 10 Hz|E*| at 10 Hz
0
100
200
300
400
500
600
Elvaloy CRA SBS LG EVA PG64 PG70 SBSRG
ESI SBS L AB EVA G
Cha
nge
in S
train
, ∆ε
, Mic
ro S
train
Permanent StrainPermanent Strain25 to 0.1 Hz25 to 0.1 Hz
10000
15000
20000
25000
30000
1.0 1.1 1.2 1.3 1.4 1.5|E*|, GPa (Simple Performance Test)
Acc
umul
ativ
e St
rain
(Sim
ple
Shea
r Tes
t)
ElvaloySBSLSBSLGPG70ABSBSRGESICRA
SST SST vs vs |E*||E*|
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0Normalized IE*I/Sinφ, SPT
Nor
mal
ized
γp
, S
ST
ABPG70PG64SBSLElvaloySBSLGEsIEVAGSBSRGCRAEVA
SST SST vs vs |E*| / Sin |E*| / Sin φφ
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0
Normalized Weighted Complex Modulus
Nor
mal
ized
SST
Per
man
ent D
efor
mat
ion
ElvaloySBSLSBSLGPG70ABSBSRGESICRA
|E*| x (|E*| x (∆∆єєmaxmax / / ∆∆єє))
SummarySummary
NCHRP 1NCHRP 1--37A37A�� Dynamic Modulus, |E*|Dynamic Modulus, |E*|�� Issues of repeatabilityIssues of repeatability�� Concern with modifiersConcern with modifiers
NCHRP 9NCHRP 9--19/2919/29�� Links Mix Design to Links Mix Design to
Structural DesignStructural Design
2002 Guide
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I N D U S T R YSUPERPAVE 2005Superpave II
SmoothRoads Ahead