1. Warm Mix Asphalt Observations from the WSDOT I-90 Job (June 2008)

2. 1.Where are we with WMA? 2.What do we know and not know? 3.Life cycle assessment 4.I-90 Observations

3. Where are we at with WMA technology?

4. WMA has been around in its current iteration since about the mid 1990s but has existed in some for or another for at least 30 years. 19952009 current WMA starts 1970s Older WMA-like products Boeing and others WMA standard use starts in some places

5. Plant foaming methods MAXAMAquaBlackFoaming attachment Terex RoadbuildingWarm mix asphalt sys.Foaming attachment Astec IndustriesDouble Barrel GreenFoaming attachment Gencor IndustriesGreen MachineFoaming attachment Kolo VeidekkeWAM FoamFoaming process Material foaming Aspha-min Zeolite powder PQ CorporationAdveraZeolite powder Additives Sasol WaxSasobitWax pellets McConnaughayLow energy asphaltChemical process LEA COLow energy asphaltChemical process Akzo NobelRediset WMXSurfactant pellets Arkema GroupCECABASE RTSurfactant chemicals MeadwestvacoEvothermSurfactant chemicals

6. The classic WMA benefits are enticing. 1.Reduced plant fuel consumption 2.Reduced emissions –At the plant –Fugitive emissions 3.Reduced viscosity during construction –Better compaction –Longer haul distances –Cold weather paving 4.Same viscosity during operation –Some have greater viscosity

7. What do we know and not know?

8. Based on published reports and presentations, here’s what we think we know. ItemEvidenceResults Field Performance Older jobs: Europe (some > 10 yrs) Newer jobs: Europe and U.S. APT: NCAT, Caltrans PRC, others ≥ HMA (not positive yet) Laboratory Performance NCAT, State DOTs, EuropeSome moisture issues Can be overcome Energy UseEurope, U.S. trials10-30% less EmissionsEurope, U.S. trials (far fewer data points) 10-70% reduction depending upon compound Fumes/smellEurope (experiment) U.S. (mostly visual) 30-50% PAH reduction CompactionEurope Numerous U.S. trials ≥ HMA AgingSome lab work, some speculationLess aging

9. What do we not yet know to our satisfaction? ItemUnknownHelp Field Performance Long-term performanceAPT (NCAT, Caltrans PRC) NCHRP Project 09-47 Laboratory Performance Mix design Characterization tests NCHRP Project 09-43 NCHRP Project 09-47 Energy UseGood protocol for quantificationLife cycle assessment (LCA) NCHRP Project 09-47 EmissionsGood protocol for quantificationLife cycle assessment (LCA) NCHRP Project 09-47 Fumes/smellQuantification is very complexSimple method needed NCHRP Project 09-47 CompactionEurope Numerous U.S. trials ≥ HMA NCHRP Project 09-47 AgingAging effects of WMALess aging SpecificationBest way(s) of doing itTWG Leader states (e.g., TX)

10. A “life cycle assessment” can help assess the energy, environmental and materials picture.

11. Life cycle assessment (LCA) is a good tool to assess the overall life cycle impact of WMA. Life cycle assessment (LCA) A protocol to assess the environmental, economic, and social impacts of an industrial system. The life cycle of the industrial system extends from cradle-to- grave: from materials acquisition and production, through manufacturing, system use and maintenance, and finally through the end of the system’s life. Essentially an accounting tool.

12. oil extraction Aggregate Quarry transport refinery transport placement transport emissions waste hazardous waste other outputs waterfuel other inputs hma plant An example of LCA processes, inputs and outputs to consider for HMA paving.

13. For a given unit of production (e.g., 1 lane-mile of pavement) a typical LCA gives a range of outputs. Amount of materials used (tonnes) Total energy use (MJ) Water consumption (kg) Emissions –Global warming potential (tonnes of CO 2 equivalent) –Nitrogen oxides – NO x (kg) –Sulfur dioxide – SO 2 (kg) –Particulate matter – PM 10 (kg) –Carbon Monoxide – CO (kg) Toxic things –Human toxicity potential –Mercury – Hg (g) –Lead – Pb (g) –Hazardous waste (kg) –Polycyclic aromatic hydrocarbons (PAHs)

14. An example of a LCA output relating to energy consumption in pavement construction. Data from: Zapata and Gambatese, Energy Consumption of Asphalt and Reinforced Concrete Pavement Materials and Construction, J. of Inf. Sys., vol. 11, issue 1, p. 9-20. Amount of Energy Required to Build 1 Lane-Mile of Pavement Notes: 90%+ from manufacturing Numbers change a lot depending on assumption 9-inch CRC Pavement (6 inches base material) 12-inch HMA Pavement (6 inches base material) 94% 3% 91%7%2% 3.7 TJ 3.0 TJ 4.0 TJ

15. An example of a LCA output relating to the contribution of different processes to environmental outcomes. Contribution of Main Processes on Environmental Impacts of HMA Hassan, M.M. (2009). Life-Cycle Assessment of Warm-Mix Asphalt: An Environmental and Economic Perspective. Presentation at the 88 th Annual Meeting of the Transportation Research Board, Washington, D.C., 11-15 January, 2009.

16. An example of a LCA output relating to waste production in roadways. Data from: Rajendran and Gambatese, Solid Waste Generation in Asphalt and Reinforced Concrete Roadway Life Cycles, J. of Inf. Sys., vol. 13, issue 2, p. 88=96. Waste Generated by 1 Lane-Mile of Pavement Notes: Most from manufacturing and EOL Numbers change a lot depending on assumption 9-inch CRC Pavement (6 inches base) 10-inch HMA Pavement (15 inches base) 41% 52% 6% 1% 38% 59% 2% 1% 2,852 tons 2,225 tons 2,000 tons

17. Total Energy Use for 1 lane-mile of HMA pavement Structure (inches) 0 12 24 = HMA = Base = Subbase

18. LCAs are a defensible protocol for quantifying the energy, environmental and materials aspects of WMA. Account for all processes associated with HMA –Include WMA additive production/transport –Include human health benefits beyond criteria pollutants Isolate improvements attributable to WMA

19. But…there are issues with the way we do LCA. Functional unit –describes the function and performance of the subject of the product or process being studied –Example: 1 lane-mile of pavement capable of supporting 100 million ESALs over 50 years Implies 1.Structural design 2.Traffic measurement 3.Defining maintenance/rehabilitation methods 4.Performance standard

20. And…we are missing a good chunk of the data we need to calculate a good LCA and it is expensive to get this data. ProcessData SourceIssues Fuel/EnergyGREETGeneric vehicle types TransportGREETGeneric vehicle types Asphalt ProductionEurobitumeDated European data Aggregate ProductionEurobitumeDated European data HMA ProductionEPA AP-42 Eurobitume Only data for average plant Cannot differentiate by process LaydownEPA NONROADUses generic engine hp sizes WMA AdditiveNoneNo good information GREET: Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation Model from Argonne National Laboratories Eurobitume: LCI report for Eurobitume (European-type Asphalt Institute) EPA NONROAD: EPA emissions model for non-road vehicles EPA AP-42: EPA emissions factors (emissions tied to quantity of material)

21. The I-90 Sasobit WMA job (June 2008)

22. 12,500 tons ½-inch Superpave 0.25-ft mill-and-fill Right lane only

23. Key Parameters HMA Class ½-inchWMA Class ½-inch Binder content5.2% Binder typePG 76-28PG 76-28 (83-28 w/Sasobit) Gyrations100 RAP content20% Tonnage7,781 tons4,724 tons Sasobit02% by binder weight Cost/ton$58.00$64.10 Production temp340-350°F300°F Laydown temp300-330°F270-300°F CPF1.031.04 Compaction PF1.02-1.051.03-1.05 Average density93.60% of Rice93.67% of Rice Fuel usage1.4 gal/ton (diesel)1.07 gal/ton (diesel) 23.5% less Roller pattern5-8 passes in 30 minsame

24. HMA: 12 June 2008

26. WMA: 23 June 2008

29. Open Path FTIR

30. Preliminary LCA results from I-90

31. Grant County power mix. This is one of the cleanest mixes in the nation.

32. A few observations. Mix temperature drives everything –We can gather less data and get same value How to simplify –Report mix temperature Temperature vs. criteria pollutants for types of plants Temperature vs. vapor pressure for HMA compounds Temperature vs. vapor pressure is NOT linear The first 50°F is bigger than the second 50°F –Report burner performance –Report fuel usage

33. Summary We have learned a lot about WMA LCA can provide a defensible protocol for analyzing environmental/energy factors Need to gather a few pieces of information to reduce the environmental data needed –HMA temperature vs. criteria pollutants –HMA temperature vs. asphalt fumes