Warm-Mix Asphalt: A Window to a Better Road Phase 1 Hosin “David” Lee, P.E. Ph.D., Professor Public Policy Center, Department of Civil and Environmental Engineering, University of Iowa President of Korean-American Scientists and Engineers Association (KSEA)

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University of Iowa in Iowa City

Global Warming Grinnell Glacier, Glacier National Park, Montana 1911 2000

Since 1979, more than 20% of the polar icecap has melted!

Climate Change is Real!

First Modern Asphalt Facility Built in 1901 by Warren Brothers in East Cambridge, Massachusetts RAP Summit held on October 9, 2008 Maximizing RAP Use - Brock NAPA website

Current Asphalt Plants in United States About 4,000 asphalt mixing plants Mostly drum mix plants Produces 500 million tons of HMA Iowa Plant

Mixing Temperatures of HMA Grade HMA Plant Mixing Temperature, °C Range Midpoint PG 58-28 127 ~ 154 140 PG 64-22 129 ~ 160 144 PG 70-22 138 ~ 165 152 PG 76-22 140 ~ 168 154

Too 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.

Worker’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. 다핵방향족탄화수소 Asphalt fumes and PAHs at the HMA job site were below the current acceptable exposure limits.

Exposure of Workers to Emissions Working at HMA and WMA Job Sites (Ruhl 2004)

Which Picture Represent WMA Construction Sites in Iowa?

WMA 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)

WMA Saves Energy Cost Compared with HMA Iceland Honolulu, HI Joliet, IL Fuel source No. 2 Fuel oil Diesel Natural gas Fuel to make 1 ton of HMA 2-3 gallons 2.5-3.5 therms Fuel Cost $2.50/gal $2.20-3.20/gal $0.70-0.80/therm Fuel Cost to make 1 ton of HMA $5.00-$7.50 $4.40-$9.00 $1.75-$2.80 Electricity to make 8-14 kWh Electricity Cost $0.02/kWh $0.1805/kWh $0.0445/kWh Average energy cost for 1 ton of HMA $5.15-$7.78 $5.84-$11.53 $2.11-$3.44 20% savings with WMA $1.00-$1.50 $0.88-$1.80 $0.35-$0.56 50% savings with WMA $2.50-$3.75 $2.20-$4.50 $0.88-$1.40 Ólöf Kristjánsdóttir (2007)

WMA Technology Category WMA Additive Company U.S. Project Organic Sasobit® Asphaltan® Licomont BS-100 Cecabase RT® LeadCap Sasobit Romonta Clariant Ceca Kumho Yes N/A Foaming Advera® Aspha-Min® Low Energy Asphalt Double-Barrel®Green Ultrafoam GX Terex®WMA System Aquablack Warm Mix Asphalt WAM-Foam Eurovia PQ Corporation McConnaughay Tech. Astec Gencor Terex Maxam Equipment Inc Kolo Veidekke, Shall Chemical Evotherm J1 RedisetTM WMA MeadWestVaco/Mathy Akzo Nobel

WMA Additives Selected for Laboratory Evaluation at the University of Iowa Organic Additives: CECABASE RT®, Sasobit® Foaming Additives: Asphalt-min®, Advera WMA Chemical Additives: Evotherm J1, RedisetTM WMX

Evaluation 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 Mixture Temperature Maximum Specific Gravity Bulk Specific Gravity Air Void Indirect Tensile Strength Test Moisture Sensitivity Test Dynamic Modulus Test Repeated Load Test

Mixing Method and Dosage Rate of WMA Additive Process Dosage Rate CECABASE RT® Wet 0.40% of binder weight Sasobit® Dry 1.50% of binder weight Asphalt-min® 0.30% of mixture weight Advera WMA® 0.25% of mixture weight Evotherm J1® 0.50% of binder weight RedisetTM WMX 2.00% of binder weight

Mix Design Parameters Aggregates Nominal Maximum Aggregate Size of 19.0 mm Ndesign 86 gyrations (for 3 million ESAL) Asphalt Content 5.5% using PG 64-34 Aggregate Heating Temp. 125°C for WMA 135°C for HMA Asphalt Heating Temp. 149°C for both WMA and HMA

Mixing and Compaction Temperatures of WMA Mixtures

Density of WMA Mixtures

Air Voids of WMA Mixtures

Moisture Sensitivity of WMA Mixtures

Asphalt Material Performance Testing (AMPT) Equipment was used to Measure Dynamic Modulus and Flow Number

Dynamic Modulus @ 4.4° C

Dynamic Modulus @ 21.1° C

Dynamic Modulus @ 37.8° C

Master Curves of WMA Mixtures

Flow Number of WMA Mixtures at 45° C 138 kPa

Ranking of ITS, TSR, Dynamic Modulus, and Flow Number of WMA Mixtures Type of Mix Ranking Average Score Indirect Tensile Strength Tensile Strength Ratio Dynamic Modulus Flow Number CECABASE RT® 9 5 8 7.75 Sasobit® (wet process) 3 6 1 2 (dry process) 4 2.75 Aspha-min® (powder) 10 - 9.5 Aspha-min® (granular) 7 7.25 Advera WMA Evotherm J1 3.75 RedisetTM WMX 3.25 Control WMA Control HMA 3.5

Summary 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.

Better Performance WMA Happier Workers Better Environment

Future Research Lime 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.

Cool-Mix Asphalt: A Door to a Better Road Phase 2 Coming in Fall 2012 near You from MATC Application of CMA with LEADCAP at 115°C in Iowa City

Questions Why should WMA be used instead of HMA? How can WMA be adopted quickly in practice? How to evaluate WMA for implementation?

Dr. Yongjoo Kim, Anand Sampath CREDITS Dr. Yongjoo Kim, Anand Sampath Nishant Sheth, Jeremy Purvis, David Blanco Korea Institute of Construction Technology (KICT) Kumho Petrochemical Ltd. This would be the last slide, click the text to change it to your information. Slide design © 2009, Mid-America Transportation Center. All rights reserved.

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