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Prepared for the WRI Symposium:
Pavement Performance PredictionGayle & Helen King
Foundation for Pavement Preservation / FHWA
Spray Applied Polymer Surface Seals
An Effective Preservation Program
Cost effectively extends pavement life
Minimizes extensive rehabilitation & resulting traffic congestion
Provides smoother, high friction surfaces
Improves ride quality & safety
Pavement Preservation Benefits of Preventive Maintenance
Pavement Structural Condition w/ time
Excellent
Good
Fair
Poor
Very Poor
Failed
40% drop in quality
75% of life
40% drop in quality
12% of life
$1.00 for PM here
Pave
men
t Str
uctu
ral C
ondi
tion
5 10 15 20
Years
Will save $3.00to $10.00 here
NOWOr here
How Do We Do It?
Asphalt Surface ApplicationsFog Seal
SealRestore AC
Dust Palliative Prime CoatTack Coat
DOT Survey
Why Fog Seal?
0 5 10 15 20 25
Reduce Oxidation
Pitting/Raveling
Reduce Shrinkdage
Close or Seal Cracks
Decrease Permeability
Construction Defects
Reduce Shrinkage
DOT SurveySurface Types That Are Fog Sealed
0 5 10 15
Dense Graded
OGFC
Chip Seals
Slurry Seal
Micro Surfacing
DOT SurveyPavement Age When Fog Seals Applied
0 2 4 6 8
At Construction
0 - 2 Years
3 - 5 Years
6 - 10 Years
> 10 Years
•Deleterious Effects of Oxygen
•Moisture Intrusion•Aggregate Loss
Fog Seals can reduce:
CONFIDENTIAL
To prevent age-induced cracking, first understand:
Asphalt Durability
Claine Petersen: A durable asphalt: 1. possesses physical properties necessary
to produce desired initial product performance &
2. is resistant to change in physical properties during long-term, in-use environmental aging
Petersen, J.C., “Chemical Composition of Asphalt as Related to Asphalt Durability-State of-the-Art”, TRR. 999, 1984
Asphalt Oxidation ChemistryThe Products
Petersen, Mill, Greene
Oxidation ProductsCarbonyls form in three steps:
KetonesCarboxylic Acids, AldehydesAcid anhydrides
Sulfoxides; Disulfoxides
For evolving rheology, carbonyls matter, sulfoxides don’t!
What about further aromatization?
Asphalt Oxidation ChemistryThe Kinetics
Petersen, Van Gooswilligen, Mill, Glover
Oxidation Kinetics Temperature dependence
G* & Carbonyl follow Arrhenius (exp (1/T)m-value – ??? (falls off a cliff)
Pressure dependence - exponentialDefined rate determining step
Bitumen, O2, catalyst
Classic phenols inhibitors don’t workIdentified reaction inhibitors (CN-)
Auto-oxidation doesn’t fit kinetics!
Asphalt Oxidation ChemistryThe Mechanisms
Petersen/Branthaver/Harnsberger, Beaver/King
Carbonyl Oxidation MechanismsDual Mechanisms – 2 reaction rates
one fast, but slows or stops with timeone slow, but continues indefinitely
N-ETIO – Electron Transfer MechanismOxycyclics explain rate determining step, unusual carbonyl products (anhydrides), influence of catalystsInitiated by triplet-to-singlet electron spin flip
Asphalt OxidationPhysical Changes
Conventional Wisdom:
Kandhal tied block cracking severity to ductility at 60ºF (15ºC)
Loss of surface fines as ductility → 10cm
Surface cracking evident when ductility falls to 5cm
“Low-Temperature Ductility in Relation to Pavement Performance”, ASTM STP 628, 1977
Asphalt OxidationPredicting Pavement Failures
Global Aging Effects ModelAs developed for MEDGUses asphalt age-hardening approach by modeling high temp ή or G*
Mirza, M.W. and Witczak, M.W., “Development of a Global Aging System for Short- and Long-Term Aging of Asphalt
Cements”, AAPT, 1995
Asphalt DurabilityPredicting Block Cracking
Challenge question:Asphalt oxidation accelerates at high
pavement temperatures, but does block cracking occur at lower temperatures?
If yes, why not use low temperature physical properties to predict block cracking?
Critique of Global Aging System:Christensen, D.W. and Bonaquist, R.F., “Volumetric
Requirements for SuperPave Mix Design”, NCHRP Report #567, TRB, 2006
WRI Aging Study - HarnsbergerARIZONA FIELD AGING
Hypothesis: Asphalts from
different crude oil sources will exhibit different field performance
ARIZONA VALIDATION SITE
Constructed Nov. 2001Shoulder cored Nov. 2005
2 – 63 mm lifts, 19-mm NMS dense graded aggregate, 4.7% AC)
Effect Of Pavement Depth On Aged Asphalt Properties
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E-06 1E-04 1E-02 1E+00 1E+02 1E+04 1E+06 1E+08 1E+10
Reduced Angular Frequency (rad/s)
Com
plex
Mod
ulus
(Pa)
Top Slice
2nd S lice
3rd Slice
Bottom Slice
AZ1-1, 4th Year, Shoulder
After Oxidation:
Top slice > 2nd slice > 3rd slice > Bottom slice
0
10
20
30
40
50
60
70
80
90
1E-06 1E-04 1E-02 1E+00 1E+02 1E+04 1E+06 1E+08 1E+10
Reduced Angular Frequency (rad/s)
Phas
e A
ngle
(deg
)
AZ1-1, 4th Year, Shoulder
Top Slice
2nd Slice
3rd Slice
Bottom Slice
EFFECT OF PAVEMENT DEPTH ON AGED ASPHALT PROPERTIES
After Oxidation:Top slice > 2nd slice > 3rd slice > Bottom slice
SuperPave Grading of Airblown ACTemperature Where SHRP Criteria are Met, °C
-40-34-28-22-16-10
-428
142026323844505662687480869298
104110116
R&B 104 R&B 125 R&B 154 R&B 172 R&B 204
G*/sin d=1.0kPa
RTFO G*/sind=2.2 kPa
PAV G* sind=5000 kPa
PAV BBRS=300 MPa
PAV BBRm=0.300
PG 52-34
PG 70-28
PG 88-4 PG 94-? PG 118-?
Comparison of m-Value & S Gradesfor AAS-1 & Exxon AC-20 at Various Aging Times
Glover, et.al. FHWA/TX-05/1872-2
Rheology Testing of Field Samples
Rheology of Extracted CoresMN 251
0
2000
4000
6000
8000
10000
12000
Reclamite PASS CRF CSS-1h GSB-B Control
G*,
PA, 1
0 ra
dian
s/se
c, 6
4 C Top Slice
Slice 2
Tested by Western Research InstituteDynamic Shear Rheometry on Liquid Samples Extracted from Field Cores (DSR)
Rheology of Core SlicesMN 251
0
50
100
150
200
250
300
350
400
450
Reclamite PASS CRF CSS-1h GSB-B Control
Tim
e to
5%
Str
ain
@ 5
8 C
(sec
) Top SliceSlice 2
Tested by Mathy Technology & Engineering Services, Inc.Dynamic Creep Test on Rectangular Specimens from Field Cores (DSR)
MN TH 251 Project - Dense-Graded, Impermeable SurfaceTests on binder from extracted cores by WRI, Tests on mix slices from cores by MTE
G*,
Pa, 1
0 ra
dian
s/se
c, 6
4C
0
5000
1000015000
20000
25000
30000
Con
trol
CSS
-1h
Rec
lam
ite
ERA-
25
ERA-
1
Pass
QB
Con
trol
Con
trol 2
CSS
-1h
Rec
lam
ite
ERA-
25
ERA-
1
Pass
QB
Test on Extracted Binder From Field Cores(G*)
Test on Mix Slices from Lab Treated Cores (Timeto 5% Strain)
0200400600800100012001400160018002000
AZ 87 Project
Tim
e to
5%
Str
ain,
58ºC
, 68k
Pa s
tres
s0
2000
4000
6000
8000
10000
12000
Rec
lam
ite
Pass
QB
CR
F
CSS
-1h
GSB
-B
Con
trol
Rec
lam
ite
Pass
QB
CR
F
CSS
-1h
GSB
-B
Con
trol
Test on Extracted Binder (G*) Test on Mix Slice (Time to 5% Strain)
050100150200250300350400450
Top 0.3" Slice2nd Layer Slice
MN 251 Project
Binder tests by WRI, Mix tests by MTE
Core Slice Binder & Mix Rheology
Fog SealLow Temperature Mix Stiffness & m-value
Bending Beam Rheometer (BBR)Rectangular beams - standard BBR geometry
$200 tile saw cuts surface mix specimens
Condition & test in BBR at -18 to -6ºC
Static Bending Test on RectangularSpecimens Cut from Field Cores (BBR)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
Con
trol
ERA
'01
Rec
lam
ite'0
1R
ecla
mite
'01
& '0
6R
ecla
mite
'06
Pass
QB
'01
CS
S '0
1
Con
trol
Rec
lam
ite'0
2R
ecla
mite
'04
CR
S-2
Pd'0
6
LD-7
'06
Pass
QB
'02
CR
F '0
2
Chi
p S
eal
CR
S-2
Pd
AZ 87 (dense-graded) MN TH 251
m-v
alue
at -
12 C
0
1000
20003000
4000
5000
6000
70008000
9000
10000
Stiff
ness
at -
12C
(MPa
)
m-valueS [MPa]
Static Bending Test on Rectangular Specimens from Field Cores Tested by Bending Beam Rheometer Cores taken in Sept and Oct 2006 - year is date of seal - Samples prepared and tested at UMinn
Hypothesis for:Cracking at low temperatures
1. Thermal Cracking1. Driven by Thermal Shrinkage Stresses on Cooling2. Function of Binder Stiffness
2. Block Cracking1. Driven by Curling Stresses from Temp Gradients2. Function of Binder Relaxation 3. Crack-Initiation Temp increases with oxidation:
Decreasing BBR ‘m-value’, but constant “S”Decreasing DTT failure strainDecreasing R-valueLower phase angle at a given modulusDecreasing Fracture energy
Research NeedsEnvironmental effects models
Predict rate of oxidative agingTemperature dependence of ??: PAV @ 3 tempsCompiled pavement temperature data from LTPPBind rutting damage model
Predict initiation of block cracking?Tools which can be used to time pavement preservation applicationsPerformance specifications
Material purchase specifications for recycling/rejuvenation binders
Fog Seals:Study Objectives
Evaluate Effectiveness of Fog SealsSealersRejuvenators
Optimize Timing Of ApplicationsEvaluate potential technologies for determining “triggers” or intervention points
Develop a Fog Seal WebsiteNCPP –www.pavementpreservation.org/fogseals/
National and Local Technology Transfer
Test Section Locations
Winlsow, AZ (3 Surfaces, 18 Test Sections)Resealed Fall ‘06
Salton Sea, CA (1 Surface, 5 TS)Marysville, CA (1 Surface, 6TS)Maple Island, MN (1 Surface, 8 TS)
Resealed Fall ’06
Rochester, MN (1 Surface, 8 TS)New trial with WRI study: Fall ’06Newly constructed pavementSanding study; evaluate early friction
Typical Pavement Trial
1 2 3 4 5 6 7 8
Reclamite Control CSS-1h GSB (B) CRF Pass Oil MegaTec Chipseal
Test Section Layout
Year Zero – Initial Application Transition Transition Transition
Year Two – Second Application
Year Four – Third Application
Outlined areas = application of material that year
Shaded areas = previously treated sections Material 1 Material 2 Material 3 Additionally, 500-ft section left untreated as control
100 ft 400ft
Evaluation Approach
Chemical & Rheological TestingFriction & Texture MeasurementNon-Destructive Testing for Assessing When to Apply TreatmentsDistress EvaluationPermeability/Infiltration Testing
Study Participants –Acknowledgements
Federal Highway Administration (FHWA) - SorensonFoundation for Pavement Preservation (FP2) - EllerArizona Department of Transportation (ADOT) - ScofieldState DOTs: MN, CA, AZ, MIGHK, Inc. – Gayle & Helen King
Research ParticipantsAcknowledgements
WRI: Binder Extraction/TestingNCSC: Friction/PermeabilityMTE: DRS TorsionUMinn: BBR on thin mixUTEP: PSPAAkzo Nobel: Emulsion Testing
Industry ParticipantsAcknowledgements
Tricor RefiningReclamite; ERA-1; ERA-25
Western EmulsionsPass QB
Blacklidge EmulsionsLD-7
Asphalt SupplyGSB-Modified
Koch MaterialsCSS
Flint Hills RefiningCRS-2Pd
Paramount RefiningCSS
Where to Use Fog Seals?
Pavement Surface TypeDense HMA
Superpave CoarseSuperpave FineSMA – “Gap-Graded Superpave”
Open-Graded Friction CourseChip Seal
New or old
Asphalt-Rubber
Fog Seal for Dense HMA
Rejuvenator Emulsions:Aromatic/Naphthenic rejuvenator oilsAC/rejuvenator oilsPMAC/rejuvenator oils
Sealer Emulsions:Dilute SS/CSSDilute RS/CRS (soap dilution)Dilute QS/CQSSpecialty emulsions
Fog Seal for OGFC
Objective:Recoat & restore aged asphalt to reduce ravelingEmulsion grades:
SS/CSSPMA chip seal emulsionsMicro-surfacing emulsionsPMA/rejuvenator oil blends
Fog Seal over Chip Seal
Objectives: Suppress dust Tie down loose aggregatePavement color (black like hot mix!)
Emulsion Grades:SS/CSSCRS/RS/HFRSPolymer-modified emulsions
Minnesota - CRS-2P (d)
Fog SealWhere to Use?
Pavement LocationTravel LanesShoulders
Color delineation for safetyReduce permeability
Airfields
Fog SealWhen to Use?
Pavement AgeSeal newer pavementsRejuvenate age-embrittled pavements
Pavement ConditionLow severity of cracking (or preferably none)RavelingAC/HMA rheology – critical “m” value
Pavement PermeabilityMix design (coarse, fine, open, SMA/gap-grade)Construction density Densification under traffic
Fog SealConstruction
Distributor Emulsion dilution/application rate?
Nozzle: size, angle, plugged?
Bar height? Bar Pressure? Speed?
Calibration
Use of fractured sandApplication rate?
Time to brooming?
Time to trafficSkid requirementsTest Strips
Fog SealProducts
Rejuvenator emulsionsOils: ETR-1; ARA-1; Reclamite®
AC/Oil: Cyclogen®; ERA®
PMAC/Oil: Pass QB®
Sealer emulsionsSS/CSS; CSS-1hP; Ralumac®
RS/CRS; CRS-2Pd, HFE-100S
QS/CQS: LD-7®
Gilsonite-based: GSB® -Modified
Fog SealField Test Methods
Pavement PermeabilityEmulsion InfiltrationSurface Modulus or “m-value”Friction
Friction of Newly Treated MN TR112 with & without Sand
From Dynamic Friction Tester/ Circular Texture Meter immediately after application and curing.Tested by North Central Superpave Center
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Control CRS 2P Pass QB LD7 ReclamiteTreatment
IFI
(Inte
rnat
iona
l Fric
tion
Inde
x)
UnsandedSanded
Change in Friction With Time After Application
Percent Change From Pre-Treatment Friction Levels Tested at 80 kph (Marysville)
-35
-30
-25
-20
-15
-10
-5
0
5
0 50 100 150 200 250 300Time Since Treatment Applied (Days)
Chan
ge
In
Fric
tion L
evel
s (%
)
ControlReclamitePass QBCQS-1hCSS-1hTopein C
Comparison of IFI and Friction Trailer (E-264) Resultson MN County Road 112
0
10
20
30
40
50
60
Control CRS-2Pd Pass QB LD-7 Reclamite
FN (I
RI x
100
)
IFI - Sanded SectionsIFIRun 1 Ribbed TireRun 2 Ribbed TireRun 3 Smooth Tire
IRI tested same day by South Central Superpave CenterE-264 by Mn/DOT several days later
r2 = 0.711 for Ribbed Tirer2 = 0.757 for Smooth Tire
Comparison of Friction TestsMN 251 – 2006 Trial
IFI as measured by DFT/CTM – Tested by North Central Superpave CenterFull-Scale Tire Testing (ASTM E-274) on MN 251 – Tested by Mn/DOT
0
10
20
30
40
50
60
70
Control Control CRS-2P(d)
LD-7 LD-7Sanded
Pass QB Reclamite ReclamiteSanded
ChipSeal/CRS-
2PdTest Section
Fric
tion
Num
ber
(Inte
rnat
iona
l Fric
tion
Inde
x (IF
I) is
X10
0
IFI (x 100)E-274 w Smooth TireE-274 w Ribbed Tire
r2 = 0.9019 for Smooth Tirer2 = 0.9125 for Ribbed Tire
Fog Seal
Lab Test Methods
Extracted Binder Rheology - DSRDSR Torsion (time to 5% strain) –Mix SurfaceBBR S & m-value – Mix SurfaceLab Permeability of Pavement CoresEmulsion Properties
Viscosity, Surface Tension, Particle Size
Emulsion Residue
Fog Seal
Binder PropertiesBinder Extraction
Toluene/95% EthanolBinder Rheology
DSR; G*, phase angle, MSCRBBR: S, “m-value”, physical hardening
Binder ChemistryInfrared Spectroscopy (IR) - carbonyl
Nuclear Magnetic Resonance (NMR) - branching
Differential Scanning Calorimetry (DSC)– wax Elemental Analysis – chemical fingerprintHPLC - EH&S issuesKing’s opinion: forget Rostler, Corbett, asphaltenes
Pavement AgingSealing Pavements
The principle of pavement seals:
Can we reduce rate of carbonyl formation by limiting the molecular oxygen in the pavement?
Answer:
Chip seals – yesFog seals – marginal improvement
How Do We Develop Specifications for Fog Seal Emulsions
Define performanceDifferentiate needs for:
Surface Type: HMA, OGFC, Chip SealTraffic: travel lane vs shoulder
Develop performance-related test methods
Create generic performance specs with defined limitsEmulsion purchase criteria
Emulsion propertiesResidue properties
Establish residue recovery method
Construction criteria
Fog Seal Specifications
CALTRANS experienceCurrent
5 essentially proprietary product-specific specs
In-Committee
5 generic prescriptive specs for product families
New Research
Performance specs for fog seal
MARTEC – Dr. Hicks
Rheology Testing of Field Samples
Rheology of Extracted CoresMN 251
0
2000
4000
6000
8000
10000
12000
Reclamite PASS CRF CSS-1h GSB-B Control
G*,
PA, 1
0 ra
dian
s/se
c, 6
4 C Top Slice
Slice 2
Tested by Western Research InstituteDynamic Shear Rheometry on Liquid Samples Extracted from Field Cores (DSR)
Rheology of Core SlicesMN 251
0
50
100
150
200
250
300
350
400
450
Reclamite PASS CRF CSS-1h GSB-B Control
Tim
e to
5%
Str
ain
@ 5
8 C
(sec
) Top SliceSlice 2
Tested by Mathy Technology & Engineering Services, Inc.Dynamic Creep Test on Rectangular Specimens from Field Cores (DSR)
MN TH 251 Project - Dense-Graded, Impermeable SurfaceTests on binder from extracted cores by WRI, Tests on mix slices from cores by MTE
Dynamic Shear Rheometryon Extracted Binder from Lab Treated Field Cores
Tested by Western Research Institute
0
5000
10000
15000
20000
25000
30000R
ecla
mite
PA
SS
ER
A-1
ERA-
25
CS
S-1
h
Con
trol
Rec
lam
ite
PA
SS
CR
F
CS
S-1
h
GS
B-B
Con
trol
AZ 87 - Dense-Graded MN 251 - Dense-Graded
G*,
Pa, 1
0 ra
dian
s/se
c, 6
4C
Top 0.3" Slice2nd Layer Slice
top related