Spray Applied Polymer Surface Seals

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Spray Applied Polymer Surface Seals

• Foundation for Pavement Preservation / FHWA

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An Effective Preservation Program

• Cost effectively extends pavement life
• Minimizes extensive rehabilitation resulting
  traffic congestion
• Provides smoother, high friction surfaces
• Improves ride quality safety

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Pavement Preservation Benefits of Preventive
Maintenance

• Pavement Structural Condition w/ time

NOW
Or here
Excellent
Good
Fair
Pavement Structural Condition
Poor
Very Poor
Failed
20
15
10
5
Years
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How Do We Do It?

• Spray Applied Emulsified Surface Applications
• Fog Seal RejuvenatorSeal
• Seal
• Restore AC

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The Spray Applied Seal Study

• Lowest cost preventive maintenance treatments
• Fog seals
• Very light application of emulsified asphalt
• Rejuvenator seals
• Emulsified oils and oil/asphalt blends to alter
  chemistry of oxidized asphalt surfaces
• Are they effective?
• Are they safe?

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Fog SealsStudy Objectives

• Evaluate Effectiveness of Fog Seals
• Sealers
• Rejuvenators
• Optimize Timing Of Applications
• Evaluate potential technologies for determining
  triggers or intervention points
• National and Local Technology Transfer

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The Project

• Information gathering
• Government/industry/academia expert task group
  advisory meetings
• State DOT survey
• Literature search
• Workshops
• Field projects testing
• Evaluate effectiveness of sealers rejuvenators
• Optimize timing of applications
• Lessons learned information sharing
• Workshops, CD, www.pavementpreservation.org/fogsea
  ls/

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1. DOT Survey
Currently use fog seals Have used in the
past Dont use Didnt respond
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DOT SurveyWhy Fog Seal?
Reduce Shrinkage
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DOT SurveySurface Types That Are Fog Sealed
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DOT SurveyPavement Age When Fog Seals Applied
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DOT SurveyAre Fog Seals Cost Effective?
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Test Section LayoutInitial Plan
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2. Test Section Locations

• AZ - US 87, Winslow (2001 2006)
• 3 Surfaces (dense, rubber, chip seal), 18 test
  sections
• CA - 78, Salton Sea (2001)
• Asphalt rubber surface, 5 sections
• CA - I-5, Marysville (2002)
• Dense-graded surface, 6 sections
• MI - M-35, Perkins, MI (2002)
• Site abandoned problems with field application
  rates
• MN - 251, Maple Island (2002, 2004, 2006)
• Dense-graded surface, 8 sections
• MN - County Rte 112, Rochester (2006)
• Coarse Superpave surface, 8 sections
• Sanding study evaluate early friction
• New trial with WRI study Fall 06
• Newly constructed pavement

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Evaluation Approach

• Chemical rheological testing
• Friction texture measurement
• Non-destructive testing for assessing when to
  apply treatments
• Distress evaluation
• Permeability/infiltration testing

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Lessons Learned
Fog seal preventing water intrusion

• MN 251 fog seal after 4 yrs in light rain

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Where to Use Fog Seals
Lessons Learned

• Pavements in good condition
• Good friction
• Minor surface distresses
• Oxidizing surfaces
• Dense-graded
• Open-graded
• Chip seals
• Shoulders

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Spray Applied Seals To Prevent
Lessons Learned
Raveling
Block Cracking
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Effect on Skid Resistance
Lessons Learned

• Friction initially reduced, but returns to
  original level with time

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Fog Seal for Dense HMA
Lessons Learned

• Rejuvenator emulsions
• Aromatic/naphthenic rejuvenator oils
• AC/rejuvenator oils
• PMAC/rejuvenator oils
• Sealer emulsions
• Dilute SS/CSS
• Dilute RS/CRS (soap dilution)
• Dilute QS/CQS
• Specialty emulsions

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Fog Seal for OGFC
Lessons Learned

• ObjectiveRecoat restore aged asphalt to
  reduce raveling
• Emulsion grades
• SS/CSS
• PMA chip seal emulsions
• Micro-surfacing emulsions
• PMA/rejuvenator oil blends

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Fog Seal over Chip Seal
Lessons Learned

• Objectives
• Suppress dust
• Tie down loose aggregate
• Reduce raveling / snow plow damage
• Pavement color (black like hot mix)
• Emulsion Grades
• SS/CSS
• CRS/RS/HFRS
• Polymer-modified emulsions
• Minnesota - CRS-2Pd

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Improve Aggregate Retention for Chip Seals
Lessons Learned
Arizona Highway 87 four yrs after fogging
Fog Seal
No Fog
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Fog SealWhere to Use?
Lessons Learned

• Pavement Location
• Travel Lanes
• Shoulders
• Color delineation for safety
• Reduce permeability
• Prolong life
• Airfields

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Fog SealWhen to Use?
Lessons Learned

• Pavement Age
• Seal newer pavements
• Rejuvenate age-embrittled pavements
• Pavement Condition
• Low severity of cracking (preferably none)
• Raveling
• AC/HMA rheology critical m value
• Pavement Permeability
• Mix design (coarse, fine, open, SMA/gap-grade)
• Construction density
• Densification under traffic

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DOT SurveyPavement Age When Fog Seals Applied
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How to Apply Seals
Lessons Learned

• Distributor well calibrated
• Correct nozzles, angle, no clogs
• Spray bar height, pattern, speed
• Test strip recommended
• Application rates depend on surface product
• Even, full coverage to protect
• No excess material to track, cause skid problems
• Experience, supplier recommendations

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How to Apply Seals
Lessons Learned

• Very low binder application
• Diluted for better control
• Avoid contamination
• Dilution at manufacturers plant
• Reduces contamination possibility
• Increases transportation costs
• Climatic conditions
• Temperature humidity to allow reasonably fast
  cure
• Sanding
• Fractured, dry sand
• After curing for rejuvenators before curing for
  asphalt seals
• Broom if adverse effect on friction, on city
  streets

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Friction of Newly Treated MN TR 112 With
Without Sand
Lessons Learned
Sanding increases friction
From Dynamic Friction Tester/ Circular Texture
Meter immediately after application and
curing. Tested by North Central Superpave Center
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Controlling Friction
Lessons Learned

• Without sand, rejuvenators can leave oily residue
  on surface of aggregates

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How to Apply Seals
Lessons Learned

• Traffic control
• Pilot car, slow speed until friction returns to
  acceptable level
• Test strip recommended
• For correct application rate
• For equipment calibration
• For traffic-return time
• For no friction or tracking surprises
• FHWA/FP2 checklist
• http//www.pavementpreservation.org/fogseals/Bibli
  ography/FHWA-FPP_Fog_Seal_Checklist.pdf

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Fog SealProducts

• Sealer emulsions
• SS/CSS CSS-1hP Ralumac?
• RS/CRS CRS-2Pd, HFE-100S
• QS/CQS LD-7?
• Gilsonite-based GSB?-Modified
• Rejuvenator emulsions
• Oils ETR-1 ARA-1 Reclamite?
• AC/Oil Cyclogen? ERA?
• PMAC/Oil Pass QB?

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Fog Seal Products
Lessons Learned

• Products differed greatly
• Curing time
• Effect on friction
• Ability to soften existing binder
• Tracking
• Dilution rate
• Application rates
• Supplier recommendations should be followed
• Product selection should be determined by
• Project goal (sealing or rejuvenating)
• Surface type (dense-graded, open-graded or chip
  seal)

Curing rejuvenator (top) fog (bottom) seals
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Fog SealField Test Methods

• Pavement permeability
• Emulsion infiltration
• Surface modulus or m-value
• Friction
• Surface texture

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Pavement PermeabilityEmulsion Infiltration
Lessons Learned

• Pavement permeability
• Pre-seal - how emulsion seal penetrates surface
• Impacts emulsion application rate
• Effectiveness of seal
• Post-seal - how seal protects surface from
  moisture air infiltration
• Performance over time
• Emulsion infiltration
• Particle size, surface tension, viscosity
• Impacts emulsion application rate
• Effectiveness of seal / rejuvenation

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Fog SealPavement Permeability
Lessons Learned

• NCAT Device
• Impossible to seal device on open-graded surface

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Fog SealEmulsion Properties
Lessons Learned

• Surface Tension
• Particle Size
• Disk Centrifuge
• Saybolt-Furol Viscosity

Not enough testing in this study for any
conclusions
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Fog SealEmulsion Infiltration
Lessons Learned

• Ring Test a bit subjective, but useful

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Fog SealSurface Modulus
Lessons Learned

• Spectral Wave Analysis with Portable Seismic
  Pavement Analyzer (PSPA)

Results showed instrument not sensitive enough to
detect differences in top 0.3 of pavement
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Fog SealFriction Texture Testing
Lessons Learned

• Dynamic Friction TestASTM E-1911

Portable, easy-to-use, repeatable
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Fog SealPavement Friction
Lessons Learned

• Circular Texture Meter ASTM E-2157

Portable, easy-to-use, repeatable
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Comparison of Friction Tests - MN251 2006
TrialDFT/CTM portable, easy-to-use, results
correlate with full scale test
Lessons Learned
IFI as measured by DFT/CTM (ASTM
E1911/E2157)Tested by North Central Superpave
Center Full-Scale Tire Testing (ASTM E274)
Tested by Mn/DOT
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Fog SealLab Test Methods

• Extracted binder rheology - DSR
• DSR torsion (time to 5 strain) mix surface
• BBR S m-value mix surface
• Lab permeability of pavement cores
• Emulsion properties
• Viscosity, surface tension, particle size
• Emulsion residue

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Fog SealBinder Properties
Lessons Learned

• Binder Extraction
• Toluene/95 Ethanol
• Binder Rheology
• DSR G, phase angle, MSCR
• BBR S, m-value, physical hardening
• Binder Chemistry
• Infrared spectroscopy (IR) - carbonyl
• Nuclear magnetic resonance (NMR) - branching
• Differential scanning calorimetry (DSC) wax
• Elemental analysis chemical fingerprint
• HPLC - EHS issues
• Rostler, Corbett, asphaltenes

Test results characterizations did not relate
much to performance
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Fog SealSurface Modulus
Lessons Learned

• Dynamic Creep (DSR Torsion)

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Core Slice Binder Mix Rheology
MN 251 Project
Time to 5 Strain, 58ºC, 68kPa stress
G, Pa, 10 radians/sec, 64C
AZ 87 Project
Binder tests by WRI, Mix tests by MTE
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Core Slice Binder Mix Rheology
Lessons Learned

• MN 251 low permeability
• Low penetration of sealers
• Little change in rheology test results
• AZ 87 more open
• Rejuvenators soften surface
• If permeability is sufficient for rejuvenator to
  penetrate
• Fog seal products stiffen open surface
• But seal aged surface from oxidation water

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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

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Static Bending Test on Rectangular Specimens Cut
from Field Cores (BBR)
Lessons Learned
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
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Static Bending Test on Rectangular Specimens Cut
from Field Cores (BBR)
Lessons Learned

• A promising new test
• Characterizes low temperature behavior
• Where cracking from oxidation most likely to
  occur
• Results from asphalt/rubber sections on CA 78 not
  repeatable
• Dense-graded surface tests showed
• Slightly better results (higher m-value) with
  polymer modified products
• Limited data tests only late in the study

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Fog SealLab Permeability
Lessons Learned
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Field Observations

• Notes photos of MN, AZ CA projects taken in
  2005 2006
• Although some 2001 and 2002 seals not clearly
  visible, effects of treatment were

Four Year Old Seals Minnesota
Arizona California
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Recommendations for Future Study

• Not in scope of study
• Simple, reliable field permeability test needed
• Develop relationship between emulsion rheology
  and infiltration
• Define procedure for optimal application rates
• Verify if pay-item test strip improves
  performance and safety
• Define sand quality for best friction
• Performance-related specifications needed to
  characterize the multitude of products

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Summary

• Fog rejuvenator seals inexpensive effective
  pavement preservation techniques
• Provide lasting protection
• Primary constraint friction loss
• Friction returns after time
• Sanding helps significantly
• Traffic control essential
• DFT / CTM useful for quick friction testing
• Seals effective over chip seals, OGFC, shoulders
• Prevent raveling
• Prolong service life
• Equipment calibration essential for success
• Performance-related specs need to be developed
• Full reports on project at www.pavementpreservati
  on.org/fogseals/

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Study Participants
Acknowledgements

• Federal Highway Administration (FHWA) - Sorenson
• Foundation for Pavement Preservation (FP2) -
  Eller
• Arizona Department of Transportation (ADOT) -
  Scofield
• State DOTs MN, CA, AZ, MI
• GHK, Inc.

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Research Participants Acknowledgements

• Western Research Institute
• Binder extraction/ chemical rheological tests
• North Central Superpave Center
• Friction/permeability
• Mathy Technology Engineering
• Dynamic shear rheometer torsion tests
• University of Minnesota
• Bending beam rheometry on thin mix
• University of Texas at El Paso
• PSPA
• Akzo Nobel
• Emulsion surface tension particle size tests

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Industry Participants Acknowledgements

• Koch Materials
• CSS-1
• Flint Hills Refining
• CRS-2Pd
• Paramount Refining
• CSS-1

• Tricor Refining
• Reclamite ERA-1 ERA-25
• Western Emulsions
• Pass QB
• Blacklidge Emulsions
• LD-7
• Asphalt Supply
• GSB-Modified

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Spray Applied Polymer Surface Seal Project