polymer modified emulsions (pme) technology deployment...
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Polymer Modified Emulsions (PME) Technology Deployment Study
An On-LineIndustry and Practitioner Survey
Background
Sponsored by the FHWA Central Federal Lands Highway Division and FHWA Office of Asset Management - (Voth, Gregory, Sorenson)
NCPP contracted to develop best practice guide and model specifications -(Galehouse, Johnston)
NCPP is actively working with a consortium of industry experts - (GHK, Inc., BASF)
Polymer Modified Emulsions (PME) Technology Deployment Study
Recommend specifications and use of polymer modified emulsions for:Chip SealsMicrosurfacing/Polymer-modified slurryCape Seals
GO-LIVE in July ’08All compliance tests must have ASTM/AASHTO approved or provisional standardUse report-only to evaluate new test methods
Goals of the Survey
1. Solicit industry input to upgrade Federal lands specifications to better identify performance enhancements of polymer-modified emulsions.
Polymer-modified Chip SealsPolymer-modified Slurry/MicroCape Seals
Goals of the Survey
2. Solicit industry input which will be used tocreate a framework for performance-based asphalt emulsion specifications
Guide documents:Pavement Preservation RoadmapTRB RNS: A New Performance Grading System for Asphalt Emulsions
Emulsion Research Programs
Manual for Emulsion-Based Chip Seals for Pavement Preservation
NCHRP 14-17 Shuler/A.Epps - $350k• Working with industry advisory panel• Residue recovery - “Stirred Can” method
Emulsion Cold MixAsphalt Research Consortium• Reporting through WRI/FHWA ETGs
Bahia/UW - $400k; Sebaaly/UNR – $200k• Consulting with industry• Develop residue recovery method• Develop performance tests
Emulsion Research Programs
Performance specifications for fog sealsFunded by CaltransCA PP Center - HicksBuilding on FPP’s Spray-Applied Sealer Study
Polymer Modified Emulsions (PME) Technology Deployment Study
FHWA Bureau of Federal Lands
PP RoadmapEmulsion Performance Specs
TRB Research Needs Statement Circulated by Moulthrop - $4.5MRecommended for priority funding by TRB’s Pavement Preservation Task Force
Support from AFK10 (General Issues in Asphalt)
The Framework
Universal criteria:Approved Emulsion Supplier Certification Program •Draft from Combined States
Laboratory Certification Program - AMRL•Is inspection/certification application-specific?
Contractor/Inspector/Individual Certification ProgramsDecision Tree for Site-selection criteria
The Framework
Update ASTM D-244 with procedures applicable to developing performance specifications for all asphalt emulsions
Residue Recovery MethodMethod for Measuring Emulsion Viscosity
Lab: Saybolt-Furol, Brookfield, Paddle Field Test
Methods to Simulate Pavement Aging (PAV)
The Framework
Application-Specific Performance SpecsEmulsion Tests/SpecificationsResidue Tests/Specifications• Rheology as tied to climate & traffic (SuperPave Tools) • Aging criteria• Polymer/modifier identification?
Aggregate & RAP Tests/SpecificationsDesign CriteriaPerformance-related Lab & Field TestsAcceptance Criteria
The PME Survey
On-line / web-accessible
Consists of six (6) primary sections which cover various technical areas related to the use of polymer modifiers in asphalt emulsions
Testing methods, acceptance criteria, certification, etc.
Questionnaire Areas
Approved Supplier Certification ProgramResidue Recovery MethodsEmulsion Specification Tests
Emulsion Residue Specifications
Application-Specific Performance Specifications
Construction/Acceptance
Reference Materials On-Line
Draft White Paper by GHK outlining major issuesNew CEN standards for emulsionsExisting specifications, testing methodsResearch on new / alternative testing methodsApplication-specific performance research on chip seals, micro-surfacing, slurry seals, etc.
TXDOT/TTI proposals
Accessing the Survey
www.pavementpreservation.org/pmesurvey/
Username: PME0108
Password: PME18002Note: Login is case-sensitive
Survey Results
Asphalt Emulsions for Maintenance Applications
19 Responses
Affiliation1 Contractor1 Trade Association2 Academics3 Consultants4 Government8 Material suppliers
Job Function1 Sales/Marketing 2 Managerial4 Regulatory12 Technical
Disclaimer: some representative comments have been included, but following graphs do not include some excellent comments and qualifiers.
Which of the following forms of certification would you support?
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101214161820
Contractor Individual Supplier Laboratory
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Others:InspectorsProject selectionShould include training program for employees
How likely are you to support a low temperature residue recovery method?
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Likely SomewhatLikely
SomewhatUnlikely
Unlikely
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Con comments:2 to 3 days is too long
Pro comments:Must be a recovery method that doesn't modify the base binderThe closer to field conditions the betterSupplier certification program will offset time concern
How likely are you to support an Approved Supplier Certification process?(working with AEMA to develop)
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Likely SomewhatLikely
Neutral Unlikely
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Is the demulsibility test needed for chip sealemulsions if a performance criterion such as the sweep test is used to establish cure rates?
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No Yes
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Con comments:A performance test is preferredThe demulsibility doesn’t tell much about field performance
Pro comments:Concerned about reliability of sweep testConcerned about time to run sweep test
Should emulsion viscosity be measured by Brookfield, rather than Saybolt-Furol?
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No Yes
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Brookfield Paddle NA
Which alternative method do you favor?
Should chip seal emulsion viscosity be raised from 100-400 sec SF to 200-500 per specifications in some states, such as ARK?
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No Yes
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Con comments:Current specs work fine for usManufactured viscosity not necessarily related to viscosity during application Viscosity is a constructibilityissue best left between the contractor and supplier
Pro comments:Depends on location, climate, other variablesLow 100's not sufficient for 70% embedment of some gradations
Should emulsions be field tested for compliance? (e.g. viscosity in WY)
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No Yes
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Con comments:If material sprays ok & doesn’t run off of road, it doesn’t need testing
Pro comments:Application vis much more important than that measured hours or days earlier or after applicationMany things can go awry once emulsion is shippedSampling, testing, testers need to be reliable
Should polymer latex be post-added to emulsions?
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No Yes
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Con comments:Our experience shows superior performance with pre-blended materialsBetter processing, more uniform product with co-milled latexVis-drop with post-add
Pro comments:Performance specs should be blind to application methodIf it works, should be allowedDepends on application
How accurate is the Elastic Recovery Test in assessing polymer presence/relative concentration?
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Accurate SomewhatAccurate
Neutral SomewhatInaccurate
Inaccurate
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Gives Customer or Agency some assurance that polymer is present but does not define the amount of polymer present.
Would you support using the Dynamic Shear Rheometer (DSR) to verify polymer properties?
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No Yes
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Con comments:Costs / time to high
Pro comments:Yes, but needs verification for emulsion residue propertiesTime efficient, low amount of binder needed Suggested tests:
FHWA MSCR, maximum phase angle, stress recoverycreep recovery
Would you support microscopy to assess polymer compatibility if in certification program rather than as a specification?
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No Yes
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Con comments:It may or may not relate to performancePerformance tests are better indicatorsProbably more applicable to hot mix than emulsions; latex is in water phase
Pro comments:Good and quick indicator of compatibility between polymer and system
Is a heat stability test necessary for emulsion residues?
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No Yes
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Con comment:Heat stability
test ensures asphalt and polymer are compatible at elevated temps in tanks
Emulsion tanks & end use are low temp
Do you support the use of Superpave binder grading tools such as the DSR, BBR, and PAV for emulsion residue specifications?
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No Yes
Nu
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expensive, time consumingRTFO, others not applicable to emulsion applications
Pro comments:Low temp residue recovery essentialBest measure for climatePAV may be informative for surface treatments
Suppliers: Are Your Willing to Provide Superpave Test Data on Your Materials?
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No Yes
Which aggregate tests are appropriate for polymer emulsion surface treatments?
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Cleanliness LAAbrasion
MicroDeval
MethylenBlue
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Others:Particle Shape, Flat & Elongated(3)FlakinessAdhesion (stripping resistance)Sand equivalency
Would you support Sweep Test to quantify curing time to traffic for chip seals?(2-levels of product performance likely based upon separate limits for curing time)
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No Yes
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Con comments:Too user dependent; still needs workShould replicate field temp & humidityTime consuming
Pro comments:Seems to be a good indicator of performanceGood tool to determine aggregate and emulsion compatibility
Should performance specifications include chip seal testing procedures which differentiate long-term chip loss? (e.g., Frosted Marble Cohesion - Vialit Plate Shock)
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No Yes
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Con comments:Chip loss often caused by construction problemsToo much testing!
Pro comments:If these tests correlate with short & long term performance, yes; if not, no
Should the current ISSA micro-surfacing performance tests for areas needing rapid cure, rut-filling, or with heavy traffic be adopted?
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No Yes
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Con comments:Overnight test strip best indicator of performance
Pro comments:Favor these type of performance testsGood, but could be improved
Should a polymer modified emulsion grade be created for micro-surfacing rut-filling?
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No Yes
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Con comments:Some polymer emulsions give excellent rutfilling; others don’tIf something works, don’t change it
Pro comments:Grade should depend on climatePerformance tests not polymer type/grade the best measure
Should the existing polymer-modified slurry specifications be upgraded for use on lower traffic areas? (only current test is wet track abrasion)
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No Yes
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Con comments:We’ve had no problems with current specsIf it works don’t change itWet track designed to determine optimal asphalt content, not specify performance
Do you support AASHTO’s current pooled-fund research to improve micro-surfacing design?
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No Yes Not familiar
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Con comments:Single spec for both micro and slurry - not practicalNo method for minimum asphalt content
Pro comments:Support automating cohesion and mix time testingResearch could lead to better performance at night, high temps & varying humidity
Not familiar with work
What’s next?
Report Results To:AEMA/ARRA/ISSA – February 22nd
Binder Expert Task Group – February 27th
Develop a Detailed Strategic PlanInitiate national effort (preservation & materials)Coordinate with Binder ETG’s Emulsion Task ForceCoordinate with ARC/NCHRP/AASHTO/CA studies
Solicit supplier supportInitiate supplier certification (AEMA/AI)Define lab testing plan for supplier round-robins
Refine & Fund RNS’s for PP Roadmap & TRB
QUESTIONS?