WMA SCAN Warm Mix Asphalt SCAN May – June 2007 Norway-Germany-Belgium-France

WMA SCAN Our Visit BackgroundBackground Warm Mix TechnologiesWarm Mix Technologies European ExperienceEuropean Experience SCAN FindingsSCAN Findings Implementation DirectionImplementation Direction

WMA SCAN Purpose of a SCAN Tour Identifies and evaluates foreign technologies and practices that could significantly benefit US transportation systemsIdentifies and evaluates foreign technologies and practices that could significantly benefit US transportation systems Main channel for accessing innovation is the International Scanning ProgramMain channel for accessing innovation is the International Scanning Program Joint program with FHWA, AASHTO, and NCHRPJoint program with FHWA, AASHTO, and NCHRP

What is WMA? Allows reduction of temperatures at which asphalt mixes are produced and placedAllows reduction of temperatures at which asphalt mixes are produced and placed –Reduces viscosity at lower temps –Allows the complete coating of aggregate –Reduces Emissions WMA SCAN

5 Classification of WMA by Temperature Range Drying Vaporization Heating Latent Heat of Vaporization

WMA SCAN Purpose of SCAN To investigate and implement innovative technologies and policies related to WMA. Topics of interest included: WMA processesWMA processes Mix design & construction practicesMix design & construction practices WMA performanceWMA performance LimitationsLimitations BenefitsBenefits

7 SCAN Team 4 DOT’s4 DOT’s –Maine –North Carolina –Nebraska –Illinois 3 FHWA3 FHWA 2 Industry Associations2 Industry Associations 2 Contractors2 Contractors 1 Chemist1 Chemist 1 Consultant1 Consultant WMA SCAN 2007

8 Who Did We Visit? Oslo, Norway Frankfurt, Germany Köln, Germany Brussels, Belgium Paris, France Nantes, France

WMA SCAN What Did the Scan Team Do?

10 Factors Driving Development of WMA The environment and sustainable development concerns, “Green Construction”The environment and sustainable development concerns, “Green Construction” –Reduction in energy consumption –Reduction in CO 2 emissions Extension of paving season and longer haul distancesExtension of paving season and longer haul distances Improvement in field compactionImprovement in field compaction Welfare of workersWelfare of workers WMA SCAN 2007

11 European Experience The for Implementation NorwayNorway –Contractor/Supplier Driven GermanyGermany –Contractor Driven –Fumes FranceFrance –Contractor Driven/Agency Supported –Sustainable Technologies NetherlandsNetherlands –Contractor Driven

12 European Mix Design Practices Mix design practices varied from country to countryMix design practices varied from country to country Some gyratory, some MarshallSome gyratory, some Marshall Some empirical, some fundamentalSome empirical, some fundamental All used performance tests!All used performance tests!

WMA Technologies Organic Additives Foaming Systems with Stabilizers Emulsion Systems Others… WMA SCAN

14 Placement and Compaction “Business as usual” Primarily use: Heavy, tamping bar, vibratory screed paversHeavy, tamping bar, vibratory screed pavers Steel-wheel vibratory and static rollersSteel-wheel vibratory and static rollers Workability generally goodWorkability generally good

15 Performance of WMA Consensus of European Countries that WMA should provide equal or better performance than HMAConsensus of European Countries that WMA should provide equal or better performance than HMA –Norway – performance mixed –Germany – performance same or better –France – toll road operator, district, and city of Paris pleased with performance to date WMA SCAN 2007

16 Benefits of WMA Reduced EmissionsReduced Emissions Reduced Fuel UsageReduced Fuel Usage Paving BenefitsPaving Benefits –Pave in cool weather –Haul mix longer distances –Improved compaction –Facilitate deep patches –Ability to use more RAP Reduced Worker ExposureReduced Worker Exposure WMA SCAN 2007

17 Reduced Emissions CO 2 SO 2 VOC CO NOx Dust

WMA SCAN SCAN Challenges

19 Adapt technologies from low production European batch/drum plants to higher production plants used in the US

20 Coarse Aggregate must be DRY Aggregates used in Europe have relatively low water absorptions, < 2%Aggregates used in Europe have relatively low water absorptions, < 2% Aggregates routinely used in the US have higher water absorptionsAggregates routinely used in the US have higher water absorptions Best Practices should be used to minimize the moisture content in aggregateBest Practices should be used to minimize the moisture content in aggregate

WMA SCAN Initial product approval; how do we sort out the good products from the bad?

Products should be approved on a national or at least a regional basis German agencies, industry, and academia have jointly developed a “Merkblatt” or guidelines for the use of WMAGerman agencies, industry, and academia have jointly developed a “Merkblatt” or guidelines for the use of WMA In France, SETRA performs certifications of new products. Cooperatively supported between agency and industryIn France, SETRA performs certifications of new products. Cooperatively supported between agency and industry WMA SCAN

23 Individual Contractors are going to have to determine which WMA process will work over the widest range of applications.

WMA SCAN Implementation Goals WMA should be an acceptable alternative to HMA at the Contractor’s discretion, provided the WMA meets applicable HMA specifications.WMA should be an acceptable alternative to HMA at the Contractor’s discretion, provided the WMA meets applicable HMA specifications.

WMA SCAN Implementation Goals An approval system needs to be developed for new WMA technologies based on performance testing and supplemented by field trials.An approval system needs to be developed for new WMA technologies based on performance testing and supplemented by field trials. –WMA TWG should lead the development of a performance based evaluation plan for new WMA products.

WMA SCAN Implementation Goals Encourage more field trials with:Encourage more field trials with: –Higher traffic –Larger size with representative production of WMA –Built in conjunction with a control section –Monitored for a minimum of three years by the agency –Data collection guidelines, developed by the WMA TWG can be found at: The factors affecting the economic viability of WMA need to be identified and tracked.The factors affecting the economic viability of WMA need to be identified and tracked.

WMA SCAN Conclusions There is a consensus among the WMA SCAN Team that WMA is a viable technology and that US Agencies and the HMA Industry need to cooperatively pursue this pathThere is a consensus among the WMA SCAN Team that WMA is a viable technology and that US Agencies and the HMA Industry need to cooperatively pursue this path The US has already made great strides in evaluating WMA, thanks in part to Public- Private Partnerships like the WMA TWG and the WMA SCAN TourThe US has already made great strides in evaluating WMA, thanks in part to Public- Private Partnerships like the WMA TWG and the WMA SCAN Tour

WMA SCAN Thank You! Questions/Discussion?