FHWA Pavements program What’s Happening...2020/01/02  · NHI Course #131109 Pilot: April 2007...

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1 1 FHWA Pavements program FHWA Pavements program What What s Happening s Happening John D John D Angelo Angelo Office of Pavement Technology Office of Pavement Technology

Transcript of FHWA Pavements program What’s Happening...2020/01/02  · NHI Course #131109 Pilot: April 2007...

Page 1: FHWA Pavements program What’s Happening...2020/01/02  · NHI Course #131109 Pilot: April 2007 Analysis of New and Rehabilitated Pavement Performance with Mechanistic-Empirical Pavement

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FHWA Pavements programFHWA Pavements programWhatWhat’’s Happenings Happening

John DJohn D’’AngeloAngeloOffice of Pavement TechnologyOffice of Pavement Technology

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Loads and Layer Stiffness

Mechanistic AnalysisLayered Elastic Analysis

E*

Mr

Mr

σ

Strain Calculations at Critical Locations

E = σ/ε

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• Downloadable, must be connected to Internet to use• Updated on NCHRP website: www.trb.org/mepdg• Voted on by the SOM and SOD • Next step AASHTO SCOH • AASHTO to develop actual design software in 2010

MEPDG Software Version 1.0

Current Status of MEPDGCurrent Status of MEPDG

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*Webcast available

Climatic Workshop LocationsWorkshop Locations

UpcomingUpcomingTraffic Traffic –– 33PMS Database Inputs PMS Database Inputs -- 11

FutureFutureLocal Calibration Local Calibration Weighing Impacts of MEPD for Next Weighing Impacts of MEPD for Next Generation Traffic DataGeneration Traffic Data

Past WorkshopsPast WorkshopsIntroduction to the DG Introduction to the DG –– 8*8*Traffic Traffic –– 22Materials Materials –– 11*11*Climatic Inputs Climatic Inputs –– 12*12*

FHWA DGIT WorkshopsFHWA DGIT Workshops

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DGIT & Office of Freight Management / Operations

Contract with Auburn University• Models in M-E PD that deal with truck size & weight • Assessing impacts of raising weight limits

FHWA cross-disciplinary cooperation team• Identify methods to assign cost to infrastructure damaged by increased highway load limits• Strive for official FHWA position on this topic

FHWA Other Activities

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National Highway Institute NHI Course #131109

Pilot: April 2007Analysis of New and Rehabilitated Pavement Performance

with Mechanistic-Empirical Pavement Design Software

• Hands-on format with computers loaded with software

• Focus on user, not theory

• Objective is for audience to be capable of performing flexible, rigid, rehab designs

Future FHWA WorkshopsFuture FHWA Workshops

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Local Calibration for M-E PDG modelsAwaiting deliverables from NCHRP 1-40 B

Pilot planned for Fall 2007

Purpose: discuss Sensitivity of inputs & calibration,

educate Pavt Designers & Pavement Managers

Future FHWA WorkshopsFuture FHWA Workshops

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Asphalt Mix Performance TesterAsphalt Mix Performance Tester

The test can evaluate the rutting and fatigue response of the mix.

The equipment is relatively inexpensive and easy to use.

Provides input data for MEPDG

Can be used for Construction acceptance.

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Asphalt Mix Performance TesterAsphalt Mix Performance Tester

•• Develop new pooled fund for purchase of Develop new pooled fund for purchase of the equipment.the equipment.

•• Establishment of a technician training Establishment of a technician training school for operation of the equipment.school for operation of the equipment.

•• Develop precision and bias for test Develop precision and bias for test procedure.procedure.

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ProblemProblem--High Temperature Binder High Temperature Binder CriteriaCriteria

•• Does G*/sinDoes G*/sinδδ reflect rutting performance of reflect rutting performance of modified binders.modified binders.–– General anecdotal data says no.General anecdotal data says no.

•• What are the alternatives?What are the alternatives?–– ZSV, LSV, Creep & Recovery testingZSV, LSV, Creep & Recovery testing

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NCHRP 9NCHRP 9--10 Rutting Test 10 Rutting Test Repeated Creep Recovery TestRepeated Creep Recovery Test

1

68

Shear Stress,

10 20

1

Shear Stain, mm/mm

10 20

Accumulated Strain

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0

5

10

15

20

25

30

0 20 40 60 80 100

Time s

Nor

mal

ized

Stra

in %

γu = Avg. un-recovered strain

Jnr = γu / τ

τ = stress applied during creep

Jnr = non-recoverable compliance

0

5

10

15

20

25

30

0 20 40 60 80 100

Time s

Nor

mal

ized

Stra

in %

γu = Avg. un-recovered strain

Jnr = γu / τ

τ = stress applied during creep

Jnr = non-recoverable compliance

New High Temp Criteria New High Temp Criteria JnrJnr

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AsAs--Built Pavement Lanes Built Pavement Lanes

CR-AZ----70-22

1

PG70-22Control

2

AirBlown

3

SBSLG

4

CR-TB

5

TP

6

PG70-22

+Fibers

7

PG70-22

8

SBS64-40

9

AirBlown

10

SBSLG

11

TP

12

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Jnr ALF binder 64C

0

0.05

0.1

0.15

0.2

0.25

0 5000 10000 15000 20000 25000 30000

Stress Pa

Jnr

64-40 64CAB 64CSBS LGcontrol 64CElvaloy 64CTBCR 64C

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HMA Layer Rutting for All Lanes

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 10,000 20,000 30,000 40,000 50,000 60,000

ALF Wheel Passes

HMA

Laye

r Rut

ting,

in.

L9S1(SBS 64-40 6")

L9S2(SBS 64-40 6")

L6S1(Terpolymer 4")

L8S1(Control 6")

L10S1(Air Blown 6")

L11S1(SBS-lg 6")

L3S1(Air Blown 4")

L2S1(Control 4")

L1S1(CR AZ 4")

L4S1(SBS-lg 4")

L12S1(Terpolymer 6")

L7S1(Fibers 4")

L5S1(TBCR 4")

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y = -7.4519x + 10.956R2 = 0.1261

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8rutting inches

G*/s

in d

64C

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Relationship between Relationship between JnrJnr and ALF and ALF ruttingrutting

y = 0.4736x - 0.1167R2 = 0.8167

0

0.05

0.1

0.15

0.2

0.25

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ALF Rutting in

Jnr

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Hamburg Rut testing MINN Road mixesHamburg Rut testing MINN Road mixesJnr 12.8kPa

y = 0.0398x - 0.0289R2 = 0.9646

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.2000

1.4000

0 5 10 15 20 25 30 35rut mm

Jnr

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Miss I55 6yr rut Miss I55 6yr rut JnrJnr 3.2 3.2 kPakPay = 0.031x

R2 = 0.7453

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 2 4 6 8 10 12rut mm

Jnr

6 yr Jnr 3.2 kPabinder mod true grad rut mm 70C

Ultrapave SBR 70-27 4.5 0.17Styrelf SB 77-29 2 0.044GTR 80 75-29 1.5 0.121Sealoflex SBS 82-27 3 0.019Multygrade 72-24 5 0.213Cryo Rubber 75-28 7 0.162Control 70-24 11 0.35

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High Temperature Binder Criteria High Temperature Binder Criteria

–– NonNon--recoverable compliance of the binder recoverable compliance of the binder describes the stress dependency of the binder.describes the stress dependency of the binder.

–– Creep and recovery testing done at multiple stress Creep and recovery testing done at multiple stress levels on one sample can be run to describe the levels on one sample can be run to describe the stress dependency of the binder.stress dependency of the binder.

–– Creep and recovery nonCreep and recovery non--recoverable compliance recoverable compliance can be correlated to mix testing done at different can be correlated to mix testing done at different stress conditions and related to performance. stress conditions and related to performance.

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Affect of Affect of JnrJnr on Ruttingon Rutting

•• Reducing Reducing JnrJnr by half typically reduced by half typically reduced rutting by half.rutting by half.

•• This affect is seen on ALF sections and This affect is seen on ALF sections and Hamburg Rut TestingHamburg Rut Testing

•• But most importantly this is seen on the But most importantly this is seen on the Mississippi I 55 sections.Mississippi I 55 sections.

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Determination of a Specification Determination of a Specification criteria.criteria.

•• The existing binder specification works The existing binder specification works very well for neat binders.very well for neat binders.

•• The grading for neat binders should not The grading for neat binders should not change.change.

•• Establish new Establish new JnrJnr criteria based on criteria based on response of neat binders at their response of neat binders at their continuous grade temp.continuous grade temp.

•• Evaluate the binders near the end of their Evaluate the binders near the end of their linear range. Most neat binders remain linear range. Most neat binders remain

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Evaluation of Straight run Evaluation of Straight run bindersbindersSample IDSample ID NameName GradeGrade true gradetrue grade TempTemp JnrJnr 3.2kPa3.2kPa

ALF 6727ALF 6727 ControlControl 7070--2222 72.772.7--74.274.2 72.772.7 0.4391220.439122

BBRS3BBRS3 straightstraight 6464--2222 66.166.1--27.327.3 66.166.1 0.4184490.418449

MN county rd 112MN county rd 112 neat Valeroneat Valero 5858--2828 60.860.8--33.433.4 60.860.8 0.3684450.368445

MN county rd 112MN county rd 112 neat neat CitgoCitgo 5858--2828 59.559.5--29.829.8 59.559.5 0.5296470.529647

MN county rd 112MN county rd 112 AshlandMAshlandM 5858--2828 60.760.7--31.431.4 60.760.7 0.4301650.430165

MinnMinn RoadRoad straightstraight 5858--2828 61.861.8--30.830.8 61.861.8 0.3029510.302951

Miss IMiss I--5555 CSLCSL 6767--2222 68.368.3--25.125.1 68.368.3 0.2669120.266912

ShandongShandong straightstraight 6464--2222 64.464.4--23.523.5 64.464.4 0.4440570.444057

BBRS3BBRS3 straightstraight 7070--2222 71.471.4--24.824.8 71.471.4 0.4808550.480855

BBRS3BBRS3 straightstraight 5858--2828 61.361.3--3030 61.361.3 0.4003450.400345

MD projectMD project straightstraight 6464--2828 64.864.8--29.629.6 64.864.8 0.4593350.459335

averageaverage 0.4127530.412753

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Grade bumping Grade bumping recommendationrecommendation

•• All testing should be done at the All testing should be done at the environmental grade temp.environmental grade temp.

•• The standard grade should be based on The standard grade should be based on the the JnrJnr value of existing neat binders 0.4 .value of existing neat binders 0.4 .

•• For high traffic the For high traffic the JnrJnr value should be value should be reduced by half at the grade temp to 0.2 reduced by half at the grade temp to 0.2 ..

•• For standing traffic the For standing traffic the JnrJnr value should value should be reduced by half again 0.1 .be reduced by half again 0.1 .

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New high Temp SpecNew high Temp Spec

•• PG 64 (Standard, Heavy, Very heavy) PG 64 (Standard, Heavy, Very heavy) based on traffic.based on traffic.–– PG 64SPG 64S--XX XX JJnrnr => 0.4=> 0.4–– PG 64HPG 64H--XX XX JJnrnr => 0.2=> 0.2–– PG 64VPG 64V--XX XX JJnrnr => 0.1=> 0.1

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How do we identify Polymers?How do we identify Polymers?Use DSR ApproachUse DSR Approach

•• Use DSR Use DSR –– MutiMuti Stress Creep Recovery TestStress Creep Recovery Test

•• Two creep stress levelsTwo creep stress levels•• Ten cycles per stress levelTen cycles per stress level•• For For ElastomericElastomeric modifiers Specify: modifiers Specify:

–– % strain recovery 3200 Pa > 15% or 20%% strain recovery 3200 Pa > 15% or 20%–– Overall change between stress levels 100Overall change between stress levels 100--3200 Pa < 3200 Pa <

75%75%

•• Run on the RTFOTRun on the RTFOT•• Run on the same sample as RTFOT grading Run on the same sample as RTFOT grading

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C reep 1st cycle 70C 1000 Pa

0

50

100

150

200

250

300

350

400

450

0 2 4 6 8 10 12

tim e

% s

trai

n

controlE lvaloyStylinkAB

What criteria? % recovered strainWhat criteria? % recovered strain

(Peak Strain - recovered Strain)/Peak Strain

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0

0.1

0.2

0.3

0.4

0.5

0.6

10 100 1000 10000 100000

Stress Pa

Jnr

poor structuregood structure

3200 Pa

MSCR selection of stress levelsMSCR selection of stress levels

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General relationship between ER General relationship between ER and MSCR and MSCR

Special EVA Incompatible SBS

20.0025.0030.0035.0040.0045.0050.0055.0060.0065.0070.0075.0080.0085.0090.00

65.00 70.00 75.00 80.00 85.00 90.00 95.00 100.00UDOT Elastic Recovery @ 25°C, %

3200

Pa

% R

ecov

ery

PG 64-28PG 64-34PG 70-28PG 58-28

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Effect of XEffect of X--linking on ERlinking on ER

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

60 65 70 75 80 85Temp C

Jnr

CI 05 ER 36.3CI 05 04 ER 56.3CI ER 32.5

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BBRS StudyBBRS Study

0

10

20

30

40

50

60

70

80

90

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Jnr

% re

cove

ry 3

.2kP

a

SBS Elva 70-28Elvaloy 70-28SBS 70-28SBR 70-22Ergon 76-22Elvaloy 76-28

64V,70S64V, 70H, 76S64V, 70S58V, 64H, 70S70V, 76H, 82S70V, 76H, 82S

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Warm Mix Task Group:Warm Mix Task Group:GaylonGaylon BaumgardnerBaumgardner

Gayle KingGayle KingGerald Gerald ReinkeReinkeMatt CorriganMatt CorriganChris Chris AbadieAbadie

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–– Question: (RTFO , PAV or both?)Question: (RTFO , PAV or both?)

•• Master Curve Development (DSR) Master Curve Development (DSR) –– PTSiPTSi•• SuperPaveSuperPave™™ True Grade (Through DTT) True Grade (Through DTT) ––

PTSiPTSi•• Physical Hardening (30 days saturation at Physical Hardening (30 days saturation at --

1212°°C) Bending Beam C) Bending Beam RheometryRheometry (BBR) (BBR) -- PTSiPTSi•• MultiMulti--Step Creep Recovery (MSCR) Step Creep Recovery (MSCR) –– FHWAFHWA•• Glass Transition Glass Transition TgTg (MDSC) (MDSC) –– WRI/MTEWRI/MTE•• Atomic Force Microscopy (AFM) Atomic Force Microscopy (AFM) ––WRIWRI

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Superpave Gyratory Superpave Gyratory Compactor CalibrationCompactor Calibration

Making Superpave MixturesMaking Superpave MixturesConsistentConsistent

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AASHTO Designation: T 312AASHTO Designation: T 312--0303Preparing ... Specimens by Preparing ... Specimens by …… SGCSGC

Superpave Gyratory CompactorSuperpave Gyratory Compactor –– …… an an average internal angle of 1.16average internal angle of 1.16°°++ 0.020.02°°……....

(only internal angle with simulated mix (only internal angle with simulated mix measurement) measurement)

4.1

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Internal Angle MeasurementInternal Angle Measurementwith Hot Mix Asphaltwith Hot Mix Asphalt

DAV on Bottomto measure αB

DAV on Topto measure αT

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APACAPACCalibrated to 1.25 degrees Calibrated to 1.25 degrees ExternalExternal

4.0 4.53.5Air Voids (Va), %

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APACAPACCalibrated to 1.16 degrees Calibrated to 1.16 degrees InternalInternal

4.03.5 4.5Air Voids (Va), %

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Asphalt InstituteAsphalt InstituteCalibrated Externally at 1.25Calibrated Externally at 1.25°°

4.5 5.04.0Air Voids (Va), %

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Asphalt InstituteAsphalt InstituteCalibrated Internally at 1.16Calibrated Internally at 1.16°°

4.54.0 5.0

Air Voids (Va), %

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University of ArkansasUniversity of ArkansasCalibrated Externally at 1.25Calibrated Externally at 1.25°°

4.5 5.04.0Air Voids (Va), %

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University of ArkansasUniversity of ArkansasCalibrated Internally at 1.16Calibrated Internally at 1.16°°

4.54.0 5.0Air Voids (Va), %

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HMS & RAMHMS & RAM

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Specification RecommendationsSpecification Recommendations•• Drop procedures related to use of HMADrop procedures related to use of HMA

–– drop reference in T312; eliminate TP48drop reference in T312; eliminate TP48

•• Implement new TP for simulated loadingImplement new TP for simulated loading–– add reference in T312add reference in T312–– Precision: Precision: TroxlerTroxler 4140 NOT INCLUDED4140 NOT INCLUDED–– Refer to Refer to ““manufacturersmanufacturers’’ recommendationsrecommendations””

•• Applies to specific procedures for using various devicesApplies to specific procedures for using various devices•• Applies to hotApplies to hot--versusversus--cold cold question(squestion(s).).

–– Inform users that RAM Inform users that RAM ~~ DAV2/HMSDAV2/HMS

•• Angle tolerance: move to +/Angle tolerance: move to +/-- 0.03 deg0.03 deg

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EFFECT OF EFFECT OF DESIGN COMPACTION DESIGN COMPACTION

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19 MM MIXTURES

-2.0%

-1.0%

0.0%

1.0%

2.0%

3.0%

-60 -40 -20 0 20 40 60

Change In Gyrations

Cha

nge

in V

MA

Effect on VMAEffect on VMAAggregate Blend Constant

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Effect of Design GyrationsEffect of Design Gyrations

N designN design

highhigh

lowlow

Aggregate Properties Constant (gradation, CAA, FAA)Aggregate Properties Constant (gradation, CAA, FAA)

% Asphalt% Asphalt

lowlow

highhigh

LABLAB ROADROAD

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Effect on StiffnessEffect on Stiffness

-

20,000

40,000

60,000

80,000

100,000

120,000

-60 -40 -20 0 20 40Change from Design Gyrations

60

G*(

0.1H

z), k

Pa

Volumetric Properties Constant

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Effect of Design GyrationsEffect of Design Gyrations

N designN design

highhigh

lowlow

Volumetric Properties Constant (air voids, VMA, VFA)Volumetric Properties Constant (air voids, VMA, VFA)

SkeletonSkeleton

strongstrong

weakweak

LABLAB ROADROAD

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What Should Design Gyrations What Should Design Gyrations Be?Be?

•• 2020--30 gyrations changes30 gyrations changes–– VMA by 1%VMA by 1%

0.4% asphalt content0.4% asphalt content

–– Mixture stiffness by 25 to 30%Mixture stiffness by 25 to 30%about one PG high temp grade differenceabout one PG high temp grade difference

–– SO . . . . . . .SO . . . . . . .

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Average Design High Air Temperature

<39 C

39 – 40 C

41 - 42 C

41 – 44 C

Design

ESALs

Millions Nini

Ndes

Nma

x

Nini

Ndes

Nma

x

Nini

Ndes

Nma

x

Nini

Ndes

Nma

x

< 0.3

7 68

104

7

74

114

7

78

121

7

82

127

< 1

7

76

117

7

83

129

7

88

138

8

93

146

< 3

7

86

134

8

95

150

8

100

158

8

105

167

< 10

8

96

152

8

106

169

8

113

181

9

119

192

< 30 8

109

174

9

121

195

9

128

208

9

135

220

< 100 9

126

204

9

139

228

9

146

240

10

153

253

> 100

9

142

233

10

158

262

10

165

275

10

172

288

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CompactionParameters

EstimatedDesign Traffic

Level(Millions1

ESALs) Ninit Ndes Nmax

< 0.3 6 50 75

0.3 to < 3 7 75 115

3 to < 30 8 100 160

≥ 30 9 125 205

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In Superpave (Marshall too)In Superpave (Marshall too)

•• Air voids and VMA specifiedAir voids and VMA specified–– Controls asphalt contentControls asphalt content

•• Gradation is notGradation is not

–– SO . . . . to change asphalt content, change VMA SO . . . . to change asphalt content, change VMA requirementrequirement

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Effect of Design GyrationsEffect of Design Gyrations

N designN design

highhigh

lowlow

Volumetric Properties Constant (air voids, VMA, VFA)Volumetric Properties Constant (air voids, VMA, VFA)

SkeletonSkeleton

strongstrong

weakweak

LABLAB ROADROAD

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CONCLUSIONSCONCLUSIONS

•• Density at end of service life not Density at end of service life not appropriate to define N designappropriate to define N design

•• NN--design does not influence asphalt design does not influence asphalt contentcontent

•• NN--design in Superpave is design in Superpave is ““in the ball parkin the ball park””

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9-9 (1) Proposed Ndesign Levels

2020--Year Design Year Design Traffic, ESALsTraffic, ESALs

22--Year Design Year Design Traffic, ESALsTraffic, ESALs

Ndesign Ndesign UnmodifiedUnmodified

Ndesign PG Ndesign PG 7676--2222

< 300,000< 300,000 < 30,000< 30,000 50506565

8080

8080

100100

NANA300,000 to 300,000 to 3,000,0003,000,000

30,000 to 30,000 to 230,000230,000

5050

3,000,000 to 3,000,000 to 10,000,00010,000,000

230,000 to 230,000 to 925,000925,000

6565

10,000,000 to 10,000,000 to 30,000,00030,000,000

925,000 to 925,000 to 2,500,0002,500,000

6565

> 30,000,000> 30,000,000 > 2,500,000> 2,500,000 8080

Recommended Ndesign TableRecommended Ndesign Table

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Fine Aggregate Specific Gravity IssuesFine Aggregate Specific Gravity Issues

•• Identify problems/issues with current Identify problems/issues with current standard AASHTO T 84 standard AASHTO T 84

•• Evaluate alternate methodsEvaluate alternate methods•• Make recommendations regarding Make recommendations regarding

changes and/or new methodschanges and/or new methods•• Additional scope Additional scope ---- Mixture gravity Mixture gravity

determination issues T 209determination issues T 209

Task Group Objectives:Task Group Objectives:

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Other NCHRP ProjectsOther NCHRP Projects

99--3434: Improved Conditioning Procedure for : Improved Conditioning Procedure for Moisture SusceptibilityMoisture Susceptibility9-38: Endurance Limit of HMA Mixtures to Prevent Fatigue Cracking99--3939: : Determining Mixing and Compaction Temperatures of PG Binders in HMA99--4545: Development of Specification Criteria for : Development of Specification Criteria for Mineral Fines Used in HMAMineral Fines Used in HMA

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WARM MIX ASPHALTWARM MIX ASPHALTTECHNOLOGYTECHNOLOGY

44th Annual Idaho Asphalt Conference

October 21, 2004

Moscow, Idaho

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Thank YouThank You………………

http://www.fhwa.dot.gov/http://www.fhwa.dot.gov/pavementspavements