Semi-Circular Bending Beam Test: Effect of Loading and Mix Parameters Mansour Solaimanian, Xuan Chen, Pennsylvania State University Annual Meeting, October 19, 2017
Semi-CircularBendingBeamTest:EffectofLoadingandMixParameters
MansourSolaimanian,XuanChen,PennsylvaniaStateUniversity
AnnualMeeting,October19,2017
2
Outline
• AReviewofAsphaltConcreteFatigueTests
• Semi-CircularBeam(SCB)Test
• PSUSCBStudyandPreliminaryResults
• Summary
3
Outline
• AReviewofAsphaltConcreteFatigueTests
• Semi-CircularBeam(SCB)Test
• PSUSCBStudyandPreliminaryResults
• Summary
MonotonicTests• IndirectTensile• Semi-CircularBeam• Disk-ShapedCompactTension
CyclicTests• FourPointBendingBeam• IndirectTensile• UniaxialPush-Pull• TexasOverlay
PictureCurtesy:IPCGlobal,Umass,PennState
LabScaleTests
LabScaleTests(CyclicTests) Fatigue/CantileverTrapezoid
TexasOverlayTester
BendingBeam
6
ModelScaleAcceleratedTests• ThirdScaleModelMobilLoadSimulator(MMLS3)
7
TestTracksandFullScaleTests
PictureCurtesy:NCAT
PennStateTrack
NCATTrack
…andALF,HVS,MLS,….
8
Outline
• AReviewofAsphaltConcreteFatigueTests
• Semi-CircularBeam(SCB)Test
• PSUSCBStudyandPreliminaryResults
• Summary
9
BackgroundonSCB
• EarlyWorkonRocks(ChongandKuruppu,1984)
• IntroducingSCBforAsphaltTesting(Molenaar,2000&
2002)
• FurtherResearch(Mohammadetal.,2004)- LA
• FurtherResearch– IFIT(Alqadi etal.,2015)- IL
• ImplementationinSpecs(Mohammadetal.,LTRC,2016)
10
SCBTestApplyonRocks(InitialApplication)
PhotoSource:Limetal.1984
11
SCBTestAppliedtoRocks
PhotoSource:DynamicBehaviorofMaterials,Vol.1SCBTestingofGraniteRock
12
SCBTestAppliedtoRocks
PhotoSource:AdvancesinMaterialsScienceandEngineeringVol.2014,Article814504
Compression-InducedFractureSurfacesandFailureMechanism
13
SCBTestSetupAppliedLoad
Support Support120mm
150mm
Notch
SpecimenThickness:50 mmNotchDepth:15 mmNotchWidth:1.5 mm
14
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 1 2 3 4 5 6 7 8
Load
(N)
Displacement(mm)
Slope@InflationPoint(m)
Slope@50%PeakLoad
CriticalDisplacement
ParametersUsedForEvaluation
WorkofFracture(W")
PeakLoad(P$%&)
FI = A×G"
abs(m)G" =
W"B 4 L
FractureEnergy FlexibilityIndex
B:SpecimenThicknessL:LigamentLength
A:Constant
StiffnessIndexSlope@50%PeakLoadinPre-PeakCurve
15PlotSource:Mohammadetal.2012
NotchDepth:
25.4 mm
NotchDepth:
31.8 mm
NotchDepth:
38.0mm
LouisianaSCBMethod(JIntegralConcept)
StrainEnergytoFailure
16
PlotSource:Elseifietal.2012
LouisianaSCBMethod(JIntegralConcept)
𝐽7 = −1𝑏𝑑𝑈𝑑𝑎 =
𝑈>𝑏>−𝑈?𝑏?
1𝑎? − 𝑎>
Where:𝐽7 =Criticalstrainenergyreleaserate,KJ/m2;b=Specimenthickness,m;a=Notchdepth,m;andU=Strainenergytofailure,kN-morKJ.
thickness:50mmmultiple-notchdepths(25.4/31.8/38mm)
𝑱𝒄 :slopeofthenotchdepthvs.strainenergyplot
17
AdvantagesofSCBTest
• SpecimenEasilyPreparedUsingSGCorFieldCores
• FourSpecimensfromOneCompactedMix
• EasytoPerformandSimpletoAnalyze
• PossibleToPerformTestUsingMarshall-TypeStabilityTester
• GoodCorrelationtoFieldPerformance??
18
CurrentIssues
• WhatTestParameterstoUse?
• Whattesttemperature?
• Howfasttotest?
• Whatpass/failcriteria?
• SensitivitytoMixParameters
• Short-termagedorlong-termagedmix?
• Testrepeatabilityandreproducibility?
19
Outline
• AReviewofAsphaltConcreteFatigueTests
• Semi-CircularBeam(SCB)Test
• PSUSCBStudyandPreliminaryResults
• Summary
20
INVESTIGATE
• EffectofTestTemperature
• EffectofLoadingRateRange
• EffectofAging(shorttermvslongterm)
• EffectofBinderContentandBinderStiffness
• EffectofVoids
21
TestTemperatureI-FIT Protocol:FixedTemperatureforAllMixes,i.e.25℃
ProposedProtocol:UsingEffectiveTemperatureConceptNCHRP704:APerformance-RelatedSpecificationforHMA
Freq:LoadingFrequency,Hz;MAAT:MeanAnnualAirTemperature,℉;𝝈MAAT:StandardDeviationoftheMeanMonthlyAirTemperature;Rain:AnnualCumulativeRainfallDepth,inches;Sunshine:MeanAnnualPercentageSunshine,%;andWind:MeanAnnualWindSpeed,Mph.
Harrisburghisaround18℃
22
TestLoadingRate
CurrentProtocol:• 50mm/min(toofast,notenoughdatapoints,higherCOV)• 0.5mm/min(tooslow,affectedbycreep)
Findings:• Loadingratebetween5to20mm/minwillminimizetheeffect
ofcreep,andprovideareasonablerangeforFIforlongtermagedmix.
23
20 mm
50 mm
50 mm
20 mm
150 mm
150 mm
SpecimenPreparation
• SGCSpecimenorFieldCores
• CuttoEnsureMinimumAVGradient
• ObtainDensity
• ConditionSpecimensatTest
Temperature
• ConductTest
ItTakes 3daysfromMixingto
ObtainResults
24
SpecimensAfterCuttingReadyforTesting
SpecimensBefore(L)/After(R)Testing
25
0
500
1000
1500
2000
2500
3000
3500
0 1 2 3 4 5 6 7 8
Load
(N)
Displacement(mm)
TypicalLoadvsDisplacementCurves3Replicates,PG58-28,25°C
25mm/min
5mm/min
1 mm/min
50mm/min
26
Temperature/LoadingRateEffects
0500
100015002000250030003500400045005000
VirginAgg+P
G58+
7AV
VirginAgg+P
G58+
4AV
VirginAgg+P
G58+
7AV+
5.9B
C
VirginAgg+P
G76+
7AV
VirginAgg+P
G58+
7AV@18C
VirginAgg+P
G58+
4AV@18C
VirginAgg+P
G58+
7AV+
5.9B
C@18C
VirginAgg+P
G76+
7AV@18C
FractureEne
rgy(J/
m^2)
FractureEnergyComparison1mm/min 5mm/min 20 mm/min 50 mm/min
Tested@25℃ Tested@18℃
27
05101520253035404550
VirginAgg+P
G58+
7AV
VirginAgg+P
G58+
4AV
VirginAgg+P
G58+
7AV+
5.9B
C
VirginAgg+P
G76+
7AV
VirginAgg+P
G58+
7AV@18C
VirginAgg+P
G58+
4AV@18C
VirginAgg+P
G58+
7AV+
5.9B
C@18C
VirginAgg+P
G76+
7AV@18C
FlexibilityIn
dex
FlexibilityIndexComparison1mm/min 5mm/min 20 mm/min 50 mm/min
Tested@25℃ Tested@18℃
Temperature/LoadingRateEffects
28
StiffnessIndicesofAgedMixes
y = 1.3827x + 1846.5R² = 0.84
0
3000
6000
9000
12000
15000
0 3000 6000 9000 12000 15000
LongTe
rmAged,SI
ShortTermAged,SI
StiffnessIndex
LineofEquality
29
FactureEnergyofAgedMixes
y=0.6063x+811.61R²=0.8137
1000
1500
2000
2500
3000
3500
4000
4500
1000 1500 2000 2500 3000 3500 4000 4500
LongTe
rmAged
FractureEne
rgy(J/
m^2)
ShortTermAgedFractureEnergy(J/m^2)
FractureEnergy
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FIofAgedMixes
0
5
10
15
20
25
30
35
0 5 10 15 20 25 30 35
LongTe
rmAged
FlexibilityIn
dex
ShortTemAgedFlexibilityIndex
FlexibilityIndex1mm/min 5mm/min 20 mm/min 50 mm/min
31
Temperature/LoadingRateSweepinSCB
0
4
8
12
16
20
0 5 10 15 20 25 30 35 40
FlexibilityIn
dex
Temperature(℃)
FlexibilityIndexLongTermAged
1mm/min5mm/min20 mm/min50 mm/min
FasterLoading
32
0
500
1000
1500
2000
2500
3000
0 1 2 3 4 5 6 7 8
Load
(N)
Displacement(mm)
STOA,PG64-22,7%AV
4.7%BC 5.2%BC 5.7%BC 6.2%BC
PostPeakSlope
EffectofBinderContent
33
EffectofBinderContent
0
10
20
30
40
50
60
4 4.5 5 5.5 6 6.5 7
FlexibilityIn
dex
BinderContent(%)
7%AirVoid
PG58-28 PG64-22 PG76-22
34
EffectofBinderContent
0
5
10
15
20
25
30
35
4 4.5 5 5.5 6 6.5 7
FlexibilityIn
dex
BinderContent(%)
4%AirVoid
PG58-28 PG64-22 PG76-22
35
0
500
1000
1500
2000
2500
3000
0 1 2 3 4 5 6 7 8
Load
(N)
Displacement(mm)
STOA,7%AV,5.2%BC
PG58-28
PG64-22
PG76-22
EffectofBinderGrade(Stiffness)
36
EffectofBinderGrade(Stiffness)
0
10
20
30
40
50
60
52 58 64 70 76 82
FlexibilityIn
dex
BinderHighTemperatureGrade
7%AirVoid
4.7%BC 5.2%BC 5.7%BC 6.2%BC
37
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 2 4 6 8
Load
(N)
Displacement(mm)
TypicalLoadvs.DisplacementCurveSTOA,PG64-22,5.2%BC
2%AV
4%AV
7%AV
EffectofAirVoid
38
EffectofAirVoid
0
5
10
15
20
25
30
35
40
45
50
0 1 2 3 4 5 6 7 8 9 10 11 12
FlexibilityIn
dex
AirVoid(%)
5.2%BinderContent
PG58-28 PG64-22 PG76-22
39
TheEffectofAirVoidReportedbyUIUC
Source:Maxwell2016
40
TheEffectofAirVoidReportedbyUIUC
Source:Maxwell2016
41
CRMMixes– PeakLoad(LTOA)
42
0
200
400
600
800
1000
1200
1400
1600
1800
2000
FractureEne
rgy(J/
m2 )
PG64+22 PG58-28+10%CRM
CRMMixes– FractureEnergy(LTOA)
43
CRMMixes– FlexibilityIndex(LTOA)
0
1
2
3
4
5
6
7
8
9
10
FlexibilityIn
dex
PG64+22 PG58-28+10%CRM
44
Outline
• AReviewofAsphaltConcreteFatigueTests
• Semi-CircularBeam(SCB)Test
• PSUSCBStudyandPreliminaryResults
• Summary
45
Summary
• Higher loading rate Lower FI• Higher temperature Higher FI• Higher Binder Content Higher FI• Higher Air Void Higher FI?• Higher Aging Lower FI• Increase in Binder Stiffness (Grade)?• CRM+PG 58 higher FI compared with
PG 64
October17,2017
Thankyou!
October18,2014