“Understanding the “Understanding the Performance of Modifiers in Performance of Modifiers in
Asphalt Mixtures” Asphalt Mixtures” ––6767--80 Binder Study80 Binder Study
Materials & Construction TeamMaterials & Construction Team
Federal Highway AdministrationFederal Highway Administrationwww.TFHRC.govwww.TFHRC.gov
The SuperpaveThe Superpave®® SystemSystem
•• Performance Grade (PG) Binder SpecificationPerformance Grade (PG) Binder Specification–– Safety / Constructability Safety / Constructability (Pump(Pump--ability)ability)–– AgingAging–– Permanent Deformation Permanent Deformation (Rutting)(Rutting)–– Fatigue CrackingFatigue Cracking–– LowLow--Temperature CrackingTemperature Cracking
•• Volumetrically Based Mixture Design SystemVolumetrically Based Mixture Design System–– Gyratory Compaction (Gyratory Compaction (VVaa, VMA, VFA), VMA, VFA)–– SuperpaveSuperpave®® Performance Test(s) (|E*|, FT, FN)Performance Test(s) (|E*|, FT, FN)
Superpave PG Binder Superpave PG Binder “Purchase” Specification“Purchase” Specification
•• In Situ Permanent DeformationIn Situ Permanent Deformation–– Cumulative Plastic DeformationCumulative Plastic Deformation
•• PG Binder CharacterizationPG Binder Characterization–– Dynamic Shear RheometerDynamic Shear Rheometer–– ViscoVisco--Elastic Response (G*, Elastic Response (G*, δδ))
•• The Goal of the PG system was/is NOT to The Goal of the PG system was/is NOT to predict performance, but rather to assure good predict performance, but rather to assure good performanceperformance
FHWA Modified Binder FHWA Modified Binder Research ProgramResearch Program
Output – Validation/Calibration Data, Specification Recommendations
TRB Superpave Committee-Binder ETG-Mix/Aggregate ETG
TPF 5(019) / SPR 2(174)Technical Working GroupTWG
LaboratoryStudy 90-07Study 67-80
ALF LoadingResponse Data
CollaborativeResearchers
IndustrySupport
Technical Working Group (TWG) Meeting December 5-6, 2002(17 States, 29 Industry Partners/Collaborative Researchers)
Not YetTPF-5(019)SPR-2(174)
2001 ALF PF2001 ALF PF
1993 SHRP Validation1999 NCHRP 90-07 / 2001 ALF PF
2003 PG 67-80 Study
ConstructionConstruction RuttingRutting FatigueFatigueCrackingCracking
LowLow--TempTempCrackingCracking
MM--E ModelingE Modeling
FWD / Geogauge|E*| Study ALF / Lab ALF / Lab Lab Only
Final Test Matrix… Final Test Matrix…
AZCRM----70-22
1
PG70-22Control
2
AirBlown
3
SBS
4
TXTBCR
5
T-P
6
PG70-22
+Fibers
7
PG70-22
8
SBS64-40
9
AirBlown
10
SBS
11
T-P
12
Rutting StudyRutting Study
RealWorld
ALF –Sections
Lab –Mixture Testing
Lab –Binder Testing
ImplicitAssumption
Step 1:Binder - Mix
Step 3:Binder - ALF
Step 2:Mix - ALF
6767--80 Binder Study80 Binder StudyOutlineOutline
•• Research ApproachResearch Approach•• 6767--80 Binders80 Binders•• Mixture CharacterizationMixture Characterization•• Proposed Binder ParametersProposed Binder Parameters•• Assessment of Current ApproachAssessment of Current Approach•• Preliminary Evaluation of Proposed Preliminary Evaluation of Proposed
Parameters (PParameters (P--PG’s)PG’s)
Research ApproachResearch Approach
•• HHoo ––
The HT cThe HT c--PG PG defines the defines the temperature where temperature where mixtures yield the mixtures yield the same HT same HT performance
0
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600
800
1000
1200
64 70 76 82 88
HT c-PG, (°C)C
ycle
s to
2%
Str
ain
performance
Research ApproachResearch Approach
•• Perfect ParameterPerfect Parameter–– Y = m X + bY = m X + b–– m = zerom = zero–– b = mix constantb = mix constant–– RR22 = n/a= n/a
(Y = b) 0
200
400
600
800
1000
1200
64 70 76 82 88
HT c-PG, (°C)C
ycle
s to
2%
Str
ain
(Y = b)
Research ApproachResearch Approach
•• AnalysisAnalysis–– YYAVEAVE = Sum [ Y= Sum [ Yii ] / n] / n
–– ∆∆ Y = [(Y = [(YYAVEAVE -- YYii ]]22]]½½ / n / n
–– % % ∆∆ cPGcPG = 100 = 100 ∆∆ Y/Y/YYAVEAVE
•• Normal Distribution Normal Distribution
0
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800
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1200
1400
64 70 76 82 88
HT c-PG, (°C)C
ycle
s to
2%
Stra
in
Research ApproachResearch Approach
•• Ex. AnalysisEx. Analysis–– YYAVEAVE = 1000= 1000
–– ∆∆ Y = [300Y = [300] / 3 ] / 3
–– %%∆∆ cc--PG = 100 / 1000PG = 100 / 1000= 10 %= 10 %
0
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600
800
1000
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1400
64 70 76 82 88
HT c-PG, (°C)C
ycle
s to
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Stra
in
900 1150 950
2001 ALF PF2001 ALF PFTarget Grade, AB cTarget Grade, AB c--PG 74PG 74--2828
Binder IDBinder ID cc--PG HTPG HT cc--PG LTPG LT UTIUTI
1: AZ CR1: AZ CR2/8: Control2/8: Control3/10: Air3/10: Air--blownblown4/11: SBS4/11: SBS--lglg5: TBCR5: TBCR6/12: Terpolymer6/12: Terpolymer9: SBS 649: SBS 64--4040
n/an/a727274747474797974747171
n/an/a--2323--2828--2828--2828--3131--3838
n/an/a9595102102102102103103105105109109
UTI – Useful Temperature Index
In situ ALF BindersIn situ ALF Binders
-40
-34
-28
-2258 64 70 76 82
Continous High Temperature Grade, (c-HT) °C
c-LT
, °C
ControlAirblownSBS-lgTBCRTerpolySBS
ETG Concern
6767--80 Binders80 Binderscc--PG based on G*/sin PG based on G*/sin δδ Original/RTFOOriginal/RTFO
Binder IDBinder ID CodeCode cc--PG HTPG HT cc--PG LTPG LT
1: 1: EnviroEnviro. Friendly. Friendly2: EF + SBS2: EF + SBS3: Terpolymer3: Terpolymer4: Terpolymer4: Terpolymer5: Terpolymer5: Terpolymer6: Terpolymer6: Terpolymer
B6308B6308B6309B6309B6310B6310B6311B6311B6312B6312B6316B6316
777780805959686872728282
--2525--2424--3030--2828--3131--2424
6767--80 Binders80 Binderscc--PG based on G*/sin PG based on G*/sin δδ Original/RTFOOriginal/RTFO
Binder IDBinder ID CodeCode cc--PG HTPG HT cc--PG LTPG LT
7: TBCR7: TBCR8: TBCR8: TBCR9: TBCR9: TBCR
10: SBS LG10: SBS LG11: SBS LG11: SBS LG12: SBS LG12: SBS LG
B6313B6313B6314B6314B6315B6315B6324B6324B6325B6325B6326B6326
707076768282686877778484
--2525--2525--2323--2626--2323--2222
6767--80 Binders80 Binders
-40
-34
-28
-2258 64 70 76 82 88
Continous High Temperature Grade, (c-HT) °C
c-LT
, °C
EFEF + SBSTerpolyTBCRSBS lg
58 64 70 76 82 88
Mix DesignMix Design
FHWA 0.45 Power Chart12.5 mm Nominal Maximum Size
0.075 0.3 1.18 4.75 9.5 12.5 25192.36
0
10
20
30
40
50
60
70
80
90
100
Sieve Size, mm
Perc
ent P
assi
ng
SuperpaveSuperpave
12.5mm NMS12.5mm NMSCoarse GradedCoarse GradedPPbb = 5.3 %= 5.3 %cc--PG 74PG 74--2828NNdesigndesign = 75= 75
Mixture Test at HT cMixture Test at HT c--PGPG
• Superpave Shear Tester (SST)– Repeated Shear at Constant Height (RSCH)
• Cycles to 2% Strain Failure• Strain at 5,000 cycles• Strain at 1,000 cycles
Mixture CharacterizationMixture CharacterizationRSCH Test Results
Cycles to 2% Strain Table 1aRep. 1 Rep. 2 Rep. 3 Rep. 4
604
503
536
352
5: Terpolymer 1411 1321 2141 765 862 1300 547 42.1
1344
1784
Average STD
1: EF 331 387 575
Rep. 5
480
593
624
773
648
475 117 24.7
2: EF+SBS 1129 600 519 669 261 39.0
3: Terpolymer 499 770 1049 696 223 32.1
4: Terpolymer 501 299 712 528 211 40.0
2023
5: Terpolymer 1966 1242 936 1227 495 40.3
6: Terpolymer 2475 2201 2121 291 13.7
CV,%Binder ID
Mixture CharacterizationMixture CharacterizationRSCH Test Results
Cycles to 2% Strain Table 1aRep. 1 Rep. 2 Rep. 3 Rep. 4
447
8: TB CR 2666 464 1449 2004 267 1370 1015 74.1
613
602
369
531
427
Average STD
7: TB CR 280 796 896
Rep. 5
815
610
1001
184
433
647 268 41.4
626
8: TB CR 1873 1199 714 1002 544 54.3
9: TB CR 500 875 1194 834 285 34.1
10: SBS LG 194 344 450 308 115 37.4
11: SBS LG 707 737 944 670 198 29.6
12: SBS LG 403 827 432 543 182 33.6
CV,%Binder ID
Cycles to 2% StrainCycles to 2% StrainAverage of 5 ReplicatesAverage of 5 Replicates
0 500 1,000 1,500 2,000 2,500
SBS 84
SBS 77
SBS 68
TB 82
TB 76
TB 70
TP 82
TP 72
TP 68
TP 59
EF+80
EF 77
Superpave Shear Tester, RSCH
Ave 5Ave 5
Cycles to 2% StrainCycles to 2% StrainCoefficient of Variation (CV)Coefficient of Variation (CV)
0 20 40 60 80 100
SBS 84
SBS 77
SBS 68
TB 82
TB 76
TB 70
TP 82
TP 72
TP 68
TP 59
EF+80
EF 77
Superpave Shear Tester, RSCH
5 Rep5 Rep
Summary of Mixture TestingSummary of Mixture TestingMin & Max CV for 5 ReplicatesMin & Max CV for 5 Replicates
MixMixCycles to 2% Strain
Strain at
5000 cycles
Strain at
1000 cycles
Min CVMin CV 13.713.7 6.56.5 2.92.9
Max CVMax CV 54.354.3 40.940.9 25.725.7
The higher testing variability (CV >20%) is common at higher temperatures
SST at HT cSST at HT c--PGPGAve s = 266cAve s = 266c
0
500
1000
1500
2000
2500
52 58 64 70 76 82 88
Superpave HT c-PG Temperature, °C
SS
T C
ycle
s to
2%
Stra
in
EFEF+TPTBCRSBS
YYAVEAVE = 810 c= 810 c∆∆ Y = 324 cY = 324 c%%∆∆ cc--PG = 40 % PG = 40 % RR22 = 0.10= 0.10
Normal Distribution of SST DataNormal Distribution of SST Data
0.000
0.004
-1000 0 1000 2000 3000 4000Cycles to 2% Strain, RSCH
Dis
tribu
tion
EF77 EF+80 TP59 TP68 TP72 TP82 TBCR70 TBCR76TBCT82 SBS68 SBS77 SBS84 Filter
Filtered w/oTP 72 (67 %)TP 82 (100 %)TBCR 76 (49 %)
Filter + 2s
SST at HT cSST at HT c--PGPGAve s = 91x10 Ave s = 91x10 --4 4
0
100
200
300
400
500
600
700
52 58 64 70 76 82 88
Superpave HT c-PG Temperature, °C
SST
Stra
in a
t 500
0c x
10 4
EFEF+TPTBCRSBS
YYAVEAVE = 439= 439∆∆ Y = 70.2Y = 70.2%%∆∆ cc--PG = 16 % PG = 16 % RR22 = 0.11= 0.11
SST at HT cSST at HT c--PGPGAve s = 32x10 Ave s = 32x10 --4 4
0
50
100
150
200
250
300
350
52 58 64 70 76 82 88
Superpave HT c-PG Temperature, °C
SST
Stra
in a
t 100
0c x
10 4
EFEF+TPTBCRSBS
YYAVEAVE = 238= 238∆∆ Y = 30.1Y = 30.1%%∆∆ cc--PG = 13 % PG = 13 % RR22 = 0.11= 0.11
High Spec. Temperature, THigh Spec. Temperature, THSHS
•• |G*|/sin |G*|/sin δ = 2200 Paδ = 2200 Pa at 10 rads/sat 10 rads/s (Superpave)(Superpave)
•• |G*|/(1|G*|/(1--(1/tan(1/tanδδ sinsinδ)) = 50 Paδ)) = 50 Pa at 0.25 rads/sat 0.25 rads/sCriterion 1 Criterion 1 (FHWA)(FHWA)
•• TTE E /(1/(1--(1/tan(1/tanδδ sinsinδ)) where Tδ)) where TEE is when |G*|= 50 is when |G*|= 50 PaPa at 0.25 rads/sat 0.25 rads/sCriterion 2 Criterion 2 (FHWA)(FHWA)
High Spec. Temperature, THigh Spec. Temperature, THSHS
•• η’ = 220 Paη’ = 220 Pa--ss, LSV , LSV at 0.01 rads/sat 0.01 rads/s (Binder ETG)(Binder ETG)
•• ηη00 = 250 Pa= 250 Pa--ss, ZSV , ZSV at 0 rads/sat 0 rads/s (Binder ETG)(Binder ETG)
•• MVR MVR = 50 cc/10min= 50 cc/10min at 1.225 kg loadat 1.225 kg load (FHWA)(FHWA)
High Temperature ParametersHigh Temperature Parameters
•• % γ% γaccacc Repeated Creep Repeated Creep @@300 Pa 300 Pa (NCHRP 9(NCHRP 9--10)10)
•• % γ% γaccacc Repeated Creep Repeated Creep @@25 Pa 25 Pa (NCHRP 9(NCHRP 9--10)10)
High Temperature ParametersHigh Temperature Parameters
•• NonNon--recovered Compliance after 50 cyclesrecovered Compliance after 50 cyclesRepeated Creep Repeated Creep @ @ 50Pa, 100Pa, 500Pa, 1000Pa, 50Pa, 100Pa, 500Pa, 1000Pa, 1600Pa, 3200Pa 1600Pa, 3200Pa (Binder ETG)(Binder ETG)
•• NonNon--recovered Compliance Multirecovered Compliance Multi--stress after 10 stress after 10 cyclescycles Repeated Creep Repeated Creep @ @ 25Pa, 50Pa, 100Pa, 25Pa, 50Pa, 100Pa, 200Pa, 400Pa, 800Pa, 1600Pa, 3200Pa 200Pa, 400Pa, 800Pa, 1600Pa, 3200Pa
(Binder ETG)(Binder ETG)
Binder CharacterizationBinder CharacterizationSuperpaveSuperpave®®, , |G*|/sin |G*|/sin δδ
|G*|/sinδ = 2200 Pa Table 2Rep. 1 Rep. 2 Rep. 3 Average STD
1: EF 79 80 80 80 0.136 0.17
2: EF+SBS 81 82 81 81 0.106 0.13
3: Terpolymer 60 61 61 61 0.675 1.11
4: Terpolymer 71 71 70 71 0.564 0.79
5: Terpolymer 72 72 74 73 1.058 1.45
6: Terpolymer 81 80 82 81 1.276 1.58
CV,%Binder ID
Binder CharacterizationBinder CharacterizationSuperpaveSuperpave®®, , |G*|/sin |G*|/sin δ δ
|G*|/sinδ = 2200 Pa Table 2Rep. 1 Rep. 2 Rep. 3 Average STD
7: TB CR 71 71 71 71 0.207 0.29
8: TB CR 75 77 77 77 1.077 1.41
9: TB CR 83 83 83 83 0.200 0.24
10: SBS LG 71 71 71 71 0.142 0.20
11: SBS LG 80 80 80 80 0.199 0.25
12: SBS LG 83 83 84 83 0.480 0.58
CV,%Binder ID
Summary of Binder TestingSummary of Binder TestingMin & Max CV for 3 ReplicatesMin & Max CV for 3 Replicates
BinderBinder G*/sin δSuperpaveSuperpave
f(G*,δ)CriterionCriterion 11
FHWAFHWA
f(G*,δ)CriterionCriterion 22
FHWAFHWA
LSV LSV BinderETGBinderETG
ZSV ZSV BinderETGBinderETG
MVRMVRFHWAFHWA
Min CVMin CV 0.130.13 0.070.07 0.050.05 0.200.20 0.080.08 0.000.00
Max CVMax CV 1.581.58 1.361.36 1.811.81 1.181.18 2.392.39 0.000.00
Summary of Binder TestingSummary of Binder TestingMin & Max CV for 3 ReplicatesMin & Max CV for 3 Replicates
BinderBinder%%γγaccacc
99--10 10 300Pa300Pa
%%γγaccacc99--10 10 25Pa25Pa
Min CVMin CV 0.740.74 0.550.55
Max CVMax CV 4.504.50 8.408.40
Summary of Binder TestingSummary of Binder TestingMin & Max CV for 3 ReplicatesMin & Max CV for 3 Replicates
BinderBinderNC
BinderETGBinderETG
50Pa50Pa
NCBinderETGBinderETG
100Pa100Pa
NCBinderETGBinderETG
500Pa500Pa
NCBinderETGBinderETG
1000Pa1000Pa
NCBinderETGBinderETG
1600Pa1600Pa
NCBinderETGBinderETG
3200Pa3200Pa
Min CVMin CV 0.440.44 0.540.54 1.301.30 0.400.40
5.715.71
1.211.21 1.081.08
Max CVMax CV 7.767.76 9.039.03 6.856.85 5.885.88 3.083.08
Summary of Binder TestingSummary of Binder TestingMin & Max CV for 3 ReplicatesMin & Max CV for 3 Replicates
BinderBinderNCMSBinderETGBinderETG
25Pa25Pa
NCMSBinderETGBinderETG
50Pa50Pa
NCMSBinderETGBinderETG
100Pa100Pa
NCMSBinderETGBinderETG
200Pa200Pa
NCMSBinderETGBinderETG
400Pa400Pa
Min CVMin CV 0.630.63 0.240.24 0.160.16 0.230.23 0.310.31
Max CVMax CV 5.665.66 4.794.79 5.285.28 5.575.57 5.915.91
Summary of Binder TestingSummary of Binder TestingMin & Max CV for 3 ReplicatesMin & Max CV for 3 Replicates
BinderBinderNCMSBinderETGBinderETG
800Pa800Pa
NCMSBinderETGBinderETG
1600Pa1600Pa
NCMSBinderETGBinderETG
3200Pa3200Pa
NCMSBinderETGBinderETG
2525--3200Pa3200Pa
Min CVMin CV 0.290.29 0.430.43 0.630.63 0.300.30
Max CVMax CV 5.555.55 5.715.71 5.635.63 5.245.24
Summary of BinderSummary of BinderCoefficient of Variation (CV) 3 ReplicatesCoefficient of Variation (CV) 3 Replicates
0 5 10 15 20 25 30 35 40
NCMS
NC
9-10 25Pa
9-10 300Pa
MVR
ZSV
LSV
FHWA Crit 2
FHWA Crit 1
Superpave
Range of CV for 12 Binders
HighLow
ObservationsObservations
•• The 10 Binder HT Parameter tests are The 10 Binder HT Parameter tests are repeatable for the 12 binders:repeatable for the 12 binders:–– CV for 3 replicates < 10 %CV for 3 replicates < 10 %
•• Current Superpave HT Parameter does not Current Superpave HT Parameter does not appear to fully capture rutting potential appear to fully capture rutting potential based upon SST mixture responsebased upon SST mixture response
AcknowledgementsAcknowledgements
Thanks toThanks to•• Mr. Scott Parobeck for making samples for SSTMr. Scott Parobeck for making samples for SST•• Mr. Frank Davis for generating SST dataMr. Frank Davis for generating SST data•• Ms. Susan Needham for generating DSR dataMs. Susan Needham for generating DSR data•• Dr. Ghazi AlDr. Ghazi Al--Khateeb for analyzing SST dataKhateeb for analyzing SST data•• Dr. Aroon Shenoy for summarizing the dataDr. Aroon Shenoy for summarizing the data
Next StepsNext Steps
•• Expand SST test of each Expand SST test of each binder over the predicted binder over the predicted range of crange of c--PPG’sPPG’s
•• Expand Mix testing to Expand Mix testing to include Hamburg (W/D), include Hamburg (W/D), Pine RWT ?Pine RWT ?
•• Compare proposed Compare proposed parameters
0
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1400
64 70 76 82 88
HT c-PG, (°C)C
ycle
s to
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Stra
in
parameters
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