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WAM Foam: asphalt pavements at lower temperatures WMA TWG, 12 December 2007, Hunt Valley - MD Slide 2 2 WAM Foam Basic Concept & History Field Experience Emission Reduction US Perspective Slide 3 3 100000 10000 1000 100 10 1 0.5 r 0.2 0.1 Viscosity Pa.s -60-60 32 120 210 300 390480 F Soft asphalt component Hard asphalt component PG 64-22 Basic Concept 0 50 75 25 Temperature Slide 4 4 DRYER MIXER SILO LAYING DRYER MIXER SILO LAYING TRADITIONAL HOT MIX ASPHALT WAM Foam ASPHALT MIX PROCESS 6% ASPHALT 5% FILLER 20 O C 90% AGGREGATE 1.8 % SOFT 4.2 % HARD COMPONENT 90% AGGREGATE Schematics of the typical process conditions 390 O F 300-350 O F 270-320 O F 260 O F 225 O F 180-220 O F 175-200 O F 320 O F 5% FILLER 20 O C Slide 5 5 DG 11 PG 52-28 (180/220) May 1999 1 st WAM Foam 1999 (Norway) Slide 6 6 WAM Foam after two years June 2001 Slide 7 7 foam mixer 2000 Original asphalt line New, 2 nd asphalt line WAM Foam installation in Hot Mix Asphalt plant Slide 8 Aggregate > 4 mm Soft Bitumen Aggregates 0-4 mm Hard Bitumen Foam Filler Discharge 0 25 35 55Time (s) 5 - Mixing 15 Mixing Batch Plant Mixing Cycle 3.5 ton batch Slide 9 9 WAM Foam, DG 11, PG58-22 (80 pen) May 2002 Reference, DG 11, PG58-22 (80 pen) May 2002 Field trials RV 120 September 2000 Slide 10 10 Rut development on RV 120 WAM Abg 11 3.2 mm/year 2.9 mm/r Slide 11 11 WAM Foam SMA 11, Track-paving on E6 - June 2002 Daily traffic 22000 vehicles - 65,2 kg/m 2 Slide 12 12 Adoption to Drum Mix Plant Slide 13 13 Emission measurements Source: Koenders et al, IRF 2004 Asphalt Fume Emission monitoring Slide 14 14 Emission reduction Hot Mix WAM Foam TPM = Total Particulate Matter BSM = Benzene Soluble Matter TPMBSM PLEASE NOTE: Today typical Occupational Exposure Limits in Europe and US are TPM 5 mg/m3 In this example Hot Mix emissions are still 4 times lower than OE limit !! Fume emission measurement Source: Koenders et al, IRF 2004 Slide 15 15 CO 2 emission during actual Production Slide 16 16 NO x and CO emission during actual Production Slide 17 17 54 % reduction Production process Dust emission during actual Production Slide 18 18 311 F 230 F Illustrations Slide 19 19 Illustrations HMA WAM Foam 329 F 230 F vs. Slide 20 20 What has been we achieved with WAM Foam? 30 % reduction in energy consumption, lower production costs 30 % reduction in CO 2 -emissions, a gain for the environment! 50 60 % reduction in dust emission, again a gain for the environment Fume from WAM Foam is below detection limits, Health & Safety! Reduced temperature => reduced oxidation/ageing of binder WAM Foam satisfies all Hot Mix Asphalt specifications according to Handbook 018 (Norwegian Standard) Production Capacity maintained Slide 21 21 US Perspective Binder components now available in the US Final binders: PG 70-22, PG 64-22, PG 58-28 Laboratory 2007 mixing trials at Turner Fairbank / FHWA 2007 evaluation at NCAT Included in study Industry tour 2007 Further US field verification 2008 Mid West Expand to modified grades ? Slide 22 22 US Perspective Positives (when compared to other WMA): No Additives, no expensive snake oils just add water Pre-coats Coarse Aggregate Absorptive Aggregates Challenges: Paradigm Shift Asphalt Plant Binder Blending PG Binder Grading system Performance Acceptance Projects Mix Design-Lab Foaming device Asphalt Plant Modifications