Presentation on theme: "Warm-Mix Asphalt: A Window to a Better Road Phase 1"— Presentation transcript:
1Warm-Mix Asphalt: A Window to a Better Road Phase 1 Hosin “David” Lee, P.E. Ph.D., ProfessorPublic Policy Center,Department of Civil and Environmental Engineering,University of IowaPresident of Korean-American Scientists and Engineers Association (KSEA)
2DisclaimerThe contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation University Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.
10Too High Temperature of Asphalt Mix During the past century, the asphalt industry has been concerned about keeping the temperature of asphalt mix high enough for adequate coating, placement, and compaction.An answer to the problems in coating and compaction has been to raise the temperature of asphalt mix.Now, for better performance and the environment, a new approach is to lower the temperature of asphalt mix: Warm-Mix Asphalt (WMA), a window to the future.One of the most important factors is the mat temperature.Too cold and the mix cannot be compacted - too hot and the mix will not support the rollers.
11Worker’s Exposure to Asphalt Fumes About 4,000 asphalt plants and 7,000 paving contractors employ nearly 300,000 workers in the United States.In 1977, the National Institute for Occupational Safety and Health (NIOSH) recommended that workers should not be exposed to airborne particulates at a concentration greater than 5mg/m3 during any 15-minute period.NIOSH concluded that the collective data currently available from studies on paving asphalt provided insufficient evidence for an association between lung cancer and exposure to asphalt fumes during paving.다핵방향족탄화수소Asphalt fumes and PAHs at the HMA job site were below the current acceptable exposure limits.
12Exposure of Workers to Emissions Working at HMA and WMA Job Sites (Ruhl 2004)
13Which Picture Represent WMA Construction Sites in Iowa?
14WMA Plants Reduce Greenhouse Gas The U.S. Environmental Protection Agency (EPA) issued a rule that was designed to reduce SO2 by 70% and NOx emissions by 60% by 2015.Some state and local governments require that HMA plants in some ozone sensitive areas limit asphalt production to a certain number of hours per week.WMA plants would reduce CO2 and SO2 by 30% to 40%, volatile organic compounds (VOC) by 50 percent, CO by 10% to 30%, NOx by 60% to 70% and dust by 20% to 25%.EAP (2006); Newcomb (2007); Ruhl (2004); D’Angelo (2008)
15WMA Saves Energy Cost Compared with HMA IcelandHonolulu, HIJoliet, ILFuel sourceNo. 2 Fuel oilDieselNatural gasFuel to make 1 tonof HMA2-3 gallonsthermsFuel Cost$2.50/gal$ /gal$ /thermFuel Cost to make1 ton of HMA$5.00-$7.50$4.40-$9.00$1.75-$2.80Electricity to make8-14 kWhElectricity Cost$0.02/kWh$0.1805/kWh$0.0445/kWhAverage energycost for 1 ton of HMA$5.15-$7.78$5.84-$11.53$2.11-$3.4420% savings with WMA$1.00-$1.50$0.88-$1.80$0.35-$0.5650% savings with WMA$2.50-$3.75$2.20-$4.50$0.88-$1.40Ólöf Kristjánsdóttir (2007)
16WMA Technology Category WMA Additive Company U.S. Project Organic Sasobit®Asphaltan®Licomont BS-100Cecabase RT®LeadCapSasobitRomontaClariantCecaKumhoYesN/AFoamingAdvera®Aspha-Min®Low Energy AsphaltDouble-Barrel®GreenUltrafoam GXTerex®WMA SystemAquablack Warm Mix AsphaltWAM-FoamEuroviaPQ CorporationMcConnaughay Tech.AstecGencorTerexMaxam Equipment IncKolo Veidekke, ShallChemicalEvotherm J1RedisetTM WMAMeadWestVaco/MathyAkzo Nobel
17WMA Additives Selected for Laboratory Evaluation at the University of Iowa Organic Additives:CECABASE RT®, Sasobit®Foaming Additives:Asphalt-min®, Advera WMAChemical Additives:Evotherm J1, RedisetTM WMX
18Evaluation of WMA Products in Laboratory Six WMA Mixtures:CECABASE RT®, Sasobit®, Asphalt-min®, Advera WMA, Evotherm J1, and RedisetTM WMX.Control WMA Mixture and HMA MixtureTemperatureMaximum Specific GravityBulk Specific GravityAir VoidIndirectTensile StrengthTestMoisture SensitivityTestDynamic ModulusTestRepeatedLoadTest
19Mixing Method and Dosage Rate of WMA Additive ProcessDosage RateCECABASE RT®Wet0.40% of binder weightSasobit®Dry1.50% of binder weightAsphalt-min®0.30% of mixture weightAdvera WMA®0.25% of mixture weightEvotherm J1®0.50% of binder weightRedisetTM WMX2.00% of binder weight
20Mix Design Parameters Aggregates Nominal Maximum Aggregate Size of 19.0 mmNdesign86 gyrations (for 3 million ESAL)Asphalt Content5.5% using PG 64-34Aggregate Heating Temp.125°C for WMA135°C for HMAAsphalt Heating Temp.149°C for both WMA and HMA
21Mixing and Compaction Temperatures of WMA Mixtures
31Ranking of ITS, TSR, Dynamic Modulus, and Flow Number of WMA Mixtures Type of MixRankingAverageScoreIndirect Tensile StrengthTensile Strength RatioDynamic ModulusFlow NumberCECABASE RT®9587.75Sasobit®(wet process)3612(dry process)42.75Aspha-min® (powder)10-9.5Aspha-min® (granular)77.25Advera WMAEvotherm J13.75RedisetTM WMX3.25Control WMAControl HMA3.5
32Summary and Conclusions Pavement is expected to perform better because the asphalt is not aged.Working environment will be better for construction workers with a lower amount of asphalt fumes.Based on the limited test results, Sasobit®, Evotherm J1, and RedisetTM WMX additives are effective in producing WMA mixtures in the laboratory that are comparable to HMA mixtures.In the future, the majority of asphalt mixtures will be produced at a lower temperature than today.
34Future ResearchLime and Anti-stripping Additives should be considered for WMA to improve the moisture susceptibility.To predict the rutting performance under moisture, Hamburg Wheel Tracking test should be performed.More test sections using WMA should be constructed adjacent to HMA.
35Cool-Mix Asphalt: A Door to a Better Road Phase 2 Coming in Fall 2012 near You from MATCApplication of CMA with LEADCAP at 115°C in Iowa City
36QuestionsWhy should WMA be used instead of HMA?How can WMA be adopted quickly in practice?How to evaluate WMA for implementation?