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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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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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