hurdles in bituminous binder characterization · binder structure / morphology optical microscopy /...
TRANSCRIPT
- SPE/BTM-JPP-15-07-2010
Hurdles in Bituminous Binder Characterization
Jean-Pascal Planche, Sylvia Dreessen, Dominique BassetP3 SymposiumLaramie, July 15, 2010
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Outline
Context / Objectives
What are the hurdles?
A few solutions
Lessons learned
Conclusions
Perspectives
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Context
Challenges“How to speak about innovation from old results?”: 100%RAS: Recycled Asphalt Slides !
Asphalt binders are very complexDepending on
Crude Oil OriginTemperatureAging
HMA plantIn situ
Many other factors…
Regardless of the precision of a standard and of applying best practices, difficulties inherent to asphalt binders
Tend to pop up when trying to characterize them
?
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Objective of the presentation
Present some characterization issues that are asphalt material related
Attempt to give explanations and solutionshow to deal with these issues?
Give some perspectives
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Unmodified asphalt binders
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Maltenes
Structural model of asphalt cements
Resins
Asphaltenes
Colloidal Suspension of asphaltenes in a maltene matrix
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Quite a few characterization issues
Binder generic compositionSECSolvent effect – loss of interactions / associations
Binder structure / morphologyOptical microscopy / FTIR Microscopy / ESEM…At which temperature is seen the sample?Average vs. local compositionArtifacts…
Binder mechanical propertiesClassical testing – penetration Rheology – modulus / phase angle - MSCRTTime and temperature related response / thermal history
Binder thermal propertiesOxidative aging
Loss of volatilesOxidation
Physical hardening…
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Thermal properties
Differential Scanning CalorimetryMeasure of the Glass transition temperature and crystallized fraction
Tg
CF
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Thermal propertiesIssues
Base line determinationThermal history dependency
Initial physical stateCooling or heating rate influence on Tg and on CF
0.50.5°°CC
22
55
1010°°C/minC/min
T=120°C
Conditioning @ T=25°C
Ex: Heating rate effect 6.2 % < CF < 9.5%-33°C < Tg < -28°C
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AAMAAM
Conditioning temperature Conditioning time
AAMAAM
AAGAAG
Thermal properties: Thermal history dependency
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Asphalt morphology
Phase contrast microscopy run @ 25°C, as a function of Crystallized Fraction
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Asphalt morphology
Phase contrast microscopy as a function of temperature upon cooling or heating
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Asphalt morphology
Dark Field microscopyObservations @ ambient temperature by Optical Microscopy - Dark Field Mode
Sample contrast comes from light scattered by the sampleOblique light allows seeing objects on the specimen surface
Crystallized fractions of a neat asphalt
50 µm
Different pattern with FT paraffin waxes added to a neat asphalt
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Links with asphalt mechanic properties?
G*(Pa) = τ/γ
T
rh
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Temperature, °C-50 2000 50 150100
Viscosity
T. Fraass
Thermal Susceptibility of Asphalt cements
Penetration
NF-EN 1426
Rig
idity
/ V
isco
sity
R&B softening point
NF-EN 1427
blown
waxy
800 pen
13000 Po
Delta TDelta T
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Thermal Susceptibility of Asphalt cements
Crystallized fraction (w %)
Del
ta T
°C
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Asphalt Rheology
Unaged asphalt
0
30
60
90
1E+01 1E+03 1E+05 1E+07 1E+09G* (Pa)
Asphalt Bc
T(°C) increase
Viscous
Elastic
Black space – Phase angle as a function of the stiffness modulus from DSR measurement
No shift whatsoever : a single curve… but not always!
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Asphalt Rheology
Black space diagram – effect of asphalt compositionAsphaltene and crystallized fractions
Increasing Crystallized fraction Increasing Asphaltenes
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Asphalt RheologyS
tiffn
ess
(MP
a)
0
200
400
600
800
1000
G H I J K L M N O P Q R
S 1h at -18°C S 24h at -18°C
1
1,5
2
-10 -5 0 5 10
Tconditioning - Tg (°C)
PHF
C45 D45 E60
Effect of Tg on physical hardeningInfluence of the conditioning on
the low temperature stiffness
Physical hardening effect on BBR ranking
BBR
δ(t)
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Physical Hardening factor and CF
11,5
22,5
0 2 4 6 8
Crystallized Fraction (%)
PH
F
Physical Hardening
Influence of the crystallized fraction content
T conditioning = T conditioning = --1515°°CC
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Polymer modified binders
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0
20
40
60
80
100
120
0 2 4 6 8 10 12 14 16 18
SBS content (%)
R&
B (°
C)
Phase Phase InversionInversion
Influence of SBS content on R&B & microstructureInfluence of SBS content on R&B & microstructure
ELASTOMER MODIFIED BINDERELASTOMER MODIFIED BINDER
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•• Phase Separation when SBS above 5Phase Separation when SBS above 5--7%7%
•• Stability at high SBS content around 16%Stability at high SBS content around 16%
••R&B difference not always reflecting instabilityR&B difference not always reflecting instability
ELASTOMER MODIFIED BINDER Storage stability (lab)
% SBS% SBS
SBS m binderSBS m binder
1 3 6 9 12 16
Del
ta P
en (0
.1 m
m)
NeatStored - topStored - bottom
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PmB storage stability following Stokes’ law
•• Emulsion Stability run by:Emulsion Stability run by:• Gravity (density of particles)• Viscosity = Force opposed to g
•• Particles SpeedParticles Speed•• dx/dtdx/dt = 2r²(= 2r²(ρρ22 --ρρ11 )g/9)g/9ηη
r = particles radiusρ1 = density of the external fluidρ2 = density of dropletsη
= viscosity of the media
Stokes’ law => Stokes’ law => creaming when creaming when ρρ22 < < ρρ1 1
PmB = Emulsion where droplets = swollen polymer nodulesPmB = Emulsion where droplets = swollen polymer nodules
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Elastomer Modified Binders
Influence Of Thermal History On Properties
Annealing R&B Annealing R&B 58°C58°C
A. Dony et al. BLPC 168, 7-8/90
Quench R&B 85°CQuench R&B 85°C
Annealing R&B 72Annealing R&B 72--82°C82°CQuench R&B 60°CQuench R&B 60°C
Fabrication R&B 88°CFabrication R&B 88°C
5% SBS PmB5% SBS PmB
180°C180°C
120°C120°C
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PLASTOMER MODIFIED BINDERS
δδ
Mouillet et al E&E Congress 2004
0
10
20
30
40
50
60
70
80
90
1,00E+00 1,00E+01 1,00E+02 1,00E+03 1,00E+04 1,00E+05 1,00E+06 1,00E+07 1,00E+08 1,00E+09
Complex Modulus (Pa)
Phas
e A
ngle
(°)
Complex ModulusComplex Modulus
Upon heating
Upon cooling
Thermal History dependency
Due to EVA cristallinity
Effect on binder properties
What about mix properties?
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PLASTOMER MODIFIED BINDERS Influence of Thermal History on Cristallinity - Melting
LargeaudLargeaud et alet al
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PLASTOMER MODIFIED BINDERS
Influence of thermal history on cristallinity - Crystallization
Largeaud et al
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Repeated Creep Recovery for Plastomer modified Bitumens
0
0,0005
0,001
0,0015
0,002
0,0025
0,003
0,0035
0 2 4 6 8 10 12Time (s)
Com
plia
nce
(Pa-1
)
76°C
70°C
64°C
Last cycle
Last cycle
Last cycle
First cycle
First cycle
First cycle
M18: B13 + 6% EVA-24
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Fatigue Testing of binders – DSR Time sweep
(after Anderson et al, paper # 01 3298 TRB 2001)
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Steric hardening in fatigue testing
Special Bit.
B15 & M17 B15 & M17 lowlow % CF% CF
SB mB
X linked
EVA mB
BitumensHigherHigher % CF% CF
Does S H remain under shear?
T where |G*|=45 MPa
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Steric hardening - Corrections
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600 µm
450
µm
IR Spectroscopy= Global Analysis
Polybutadiene BandPolybutadiene Band
γ γ CC--H characteristicH characteristic
IR Microscopy= Local Analysis
965 cm965 cm--11
FTIR MICROSCOPY
Mouillet et al, BLPC 2000
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Understand internal evolutions during aging
Identify chemical structures
Visualize different microphases
In situ characterizationNo interaction on internal equilibriumLocal FTIR spectroscopic technique
IR mapping to “quantify” polymer dispersion
0.17
1.30
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
Abs
orba
nce
700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 Wavenumbers (cm-1)
450µ
m
600µm
INFRARED MICROSCOPY
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FTIR MICROSCOPY of PmB’s
SBS MA
600µm
450µ
m
EVA MA
600µm
450µ
m
νC-O EVA band @ 1242cm-1
δCH3 bitumen band @ 1376cm-1
1242cm-1
1600cm-1
Mouillet et al, BLPC 2000
965cm-11376 cm-1
γCH SBS band @ 965cm-1
δCH3 bitumen band @ 1376cm-1
Colors = various levels of polymer concentrations
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ELASTOMER MODIFIED BINDERS
Microstructure of a Microstructure of a crosslinked PmB crosslinked PmB
(Styrelf®)
3 D Network3 D Network(N(N--hexane washed)hexane washed)
UV Fluorescence
0,34
0,36
FTIR Microscopy
Fine dFine dispersion of the in situ ispersion of the in situ crosslinked polymercrosslinked polymer
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Polymer-modified Bitumens aging After L. Lapalu, J-P. Planche, V. Mouillet, P. Dumas,
F. Durrieu – Eurobitume Eurasphalt Congress May 2004
Collaboration between TOTAL and LCPC
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Oxidation cell
FeaturesFeaturesTemperature sweepTemperature sweep
Oxidant or neutral gasOxidant or neutral gasHeating rateHeating rate
Top view
Gas InletGas OutletGage
GageD
Sample
Side section
To the IR detector
Gas Outlet
Gas Inlet
Sample
Oxi
datio
nt
IR Indices calculation
To To continuouslycontinuously visualize and analyze phases chemical evolutionvisualize and analyze phases chemical evolution
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T=0’
T=90’
T=30’
T=60’
T=120’
0,9%
7,8%1,0%
8,1%1,0%
9,3%1,0%
9,4%1,1%
9,5%
Conditions : 130°C / Air
Increase in EVA concentration Increase in EVA concentration in polymer nodules (7.8 to 9.5 in polymer nodules (7.8 to 9.5 %)%)
Stability of EVA concentration Stability of EVA concentration in AC matrixin AC matrix
Oxidation kinetics in the cell – 6% EVA - Bc
Exchange of asphalt molecular species between phases according to their compatibility with polymer:
Concentration of the polymer network due to a lower EVA compatibility in the oxidized bitumen
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EVA mB microstructure evolution (after Durrieu et al)
Before ageingBefore ageing
Phase inversion @ 6% EVAPhase inversion @ 6% EVA
EVAEVA swollen by slightly swollen by slightly condensed aromatics condensed aromatics substituted by aliphaticssubstituted by aliphatics7.6%
0.8%+ 6% EVA
7.6%7.6%7.6%
0.8%+ 6% EVA
7.6%
0.8%+ 6% EVA
7.6%7.6%
After RTFOT+PAV ageingAfter RTFOT+PAV ageing
Increase in EVA content in Increase in EVA content in the nodulesthe nodules
Stability of aromatics, but Stability of aromatics, but decrease in aliphatics and decrease in aliphatics and condensedcondensed
migration of the fraction migration of the fraction involved in EVA swelling to involved in EVA swelling to the surrounding matrixthe surrounding matrix
9.2%
0.4%+ 6% EVA
9.2%
0.4%+ 6% EVA
9.2%
0.4%+ 6% EVA
9.2%
0.4%+ 6% EVA
9.2%
0.4%+ 6% EVA
9.2%
0.4%+ 6% EVA
9.2%
0.4%+ 6% EVA
Validation of the oxidation cell !
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Homogenization of SBSHomogenization of SBS
Decrease in SBS in Decrease in SBS in polymer nodulespolymer nodules
Increase in SBS in AC Increase in SBS in AC matrixmatrix
Partial degradation of the polymer network
leading to a homogenization of the SBS copolymer distribution in the oxidized binder
T=120’
2,9%
6,9%
T=0’12,2%
0,6%
T=30’
0,6%
12,2%
T=60’
0,7%
11,8%
T=90’
1,5%
11,1%
Conditions : 130°C / Air
Oxidation kinetics – 6% SBS - Bc
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Crosslinking PmB
• Improvement of PMA rheological properties imparted by the crosslinking reaction on unaged binder...
0
30
60
90
1E+01 1E+03 1E+05 1E+07 1E+09G* (Pa)
Bc-SBSlin (3%)Bc-Styr1 (3%)
0
30
60
90
1E+01 1E+03 1E+05 1E+07 1E+09G* (Pa)
Bc-SBSlin (3%)
Bc-Styr1 (3%)Bc-SBSlin (3%) after RTFOT+PAV
Bc-Styr1 (3%) after RTFOT+PAV
...and after ageing• the polymer and the matrix remain compatible after ageing
elasticity on a wider temperature range
0
30
60
90
1E+01 1E+03 1E+05 1E+07 1E+09G* (Pa)
Bc-SBSlin (3%)Bc-Styr1 (3%)Bc-SBSlin (3%) after RTFOT+PAVBc-Styr1 (3%) after RTFOT+PAVBc-Styr1 (6%) after RTFOT+PAV
t=0 min RTFOT + PAV aging
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PmB Aging: Impact on low temperature properties
•• mm--value good indicator of binder agingvalue good indicator of binder aging•• Modification effect:Modification effect:
•• Positive for SBS crosslinked PmB, Negative for EVAPositive for SBS crosslinked PmB, Negative for EVA
D T iso 0.3
0
2
4
6
8
D T
iso
(°C
)
Bc 3 XLl3 XLr6 XLl6 XLr3 SBSl3 SBSr6 SBSl6 SBSr3 EVA6 EVA3 EBA 6 EBA
D Tiso 300
BBR parameters evolution vs. RTFOT+PAV aging
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Low temperature properties – Fracture mechanics
The Mode-I Fracture Test
Environmental chamber at Environmental chamber at --20°C20°CCutting of the rupture faces for Cutting of the rupture faces for CSEMCSEM or or ESEMESEM observationsobservations
TestTest
Speed = 0.6 Speed = 0.6 mm.minmm.min--11
T = T = --20°C20°C
KKICIC = failure load = failure load ×× f (span, crack length, sample dimensions)f (span, crack length, sample dimensions)
AfterAfter Lapalu et al, Eurobitume 2000Lapalu et al, Eurobitume 2000
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Fracture mechanisms
Neat bitumen (KIC = 48 kPa.m1/2)
No topographic contrastNo topographic contrastBrittle rupture Brittle rupture low Klow KICIC
6% EVA-28 blend (KIC = 74 kPa.m1/2)ESEM observation at -5°C
50 µ
m
Polymer glassy at testing temperaturePolymer glassy at testing temperature
PolymerPolymer--rich particles pulledrich particles pulled--out without out without deformationdeformation
Fracture mechanism governed by Fracture mechanism governed by the (poor) adhesion between the (poor) adhesion between phases phases low Klow KICIC
AfterAfter Lapalu et al, Eurobitume 2000Lapalu et al, Eurobitume 2000
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PhysicalPhysical blendblend 4% SBS4% SBS**
22
(K(KICIC
= 107 kPa.m= 107 kPa.m1/21/2))
4% SB 4% SB Crosslinked binder Crosslinked binder (K(KICIC
= 113 kPa.m= 113 kPa.m1/21/2))
CLSM observation at -165°C
PParticle pullarticle pull--out (crack deflection) without (crack deflection) withPlastic Deformation of SBS NodulesPlastic Deformation of SBS Nodules
SBS in rubbery state SBS in rubbery state High KHigh KICIC
AfterAfter Lapalu et al, Eurobitume 2000Lapalu et al, Eurobitume 2000
Fracture mechanisms
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Lessons learned – a few tips
N°1: Humility
Critical eye
Think global
Use the right tool
Think out of the box
Meet and work with the right peopleCross-fertilizationCompetences
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Conclusions – Key issues
Thermal historyComparing binders in the same physical state to measure intrinsic propertiesAssociations - interactionsCrystallization – precipitationMelting – solubilizationPhases – multiple – exchanges – molecule transferSwellingReactions
OxidationCross-linkingGelling…
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Maltenes
Structural model of asphalt cements
Crystallized Fractions
Resins
Asphaltenes
Colloidal Suspension of asphaltenes in a maltene matrix
And what else ?
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A few perspectives
There are powerful tools available to look at the fundamentals
Atomic force microscopy
Nano indentation
DSR - MSCRT
Modulated DSC
FTIR, ESEM microscopies
…
Let’s try to use them and interpret the results properly!
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Acknowledgements
So many people over the years…
Total group and co-workers
France: P. Claudy, D. Martin, V. Mouillet, D. Lesueur, C. Such, C. De La Roche, B. Brûlé, JM Létoffé, F. Rondelez
US: D. Anderson and his band, G. King, J. D’Angelo, J. Youtcheff, J. Brannthaver, C. Petersen R. Robertson and the WRI team
Europe: O. Harders, Pr. Neuman, S. Brown, M. Partl, D. Sylbislki, W. Arand, TU Delft team
And all I’ve forgotten: please forgive me!