WAM Foam: asphalt pavements at lower temperatures

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WAM Foam asphalt pavements at lower temperatures

• WMA TWG, 12 December 2007, Hunt Valley - MD

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WAM Foam

• Basic Concept History
• Field Experience
• Emission Reduction
• US Perspective

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Basic Concept
Viscosity
Pa.s
100000
10000
1000
100
10
1
0.5
0.2

0.1
300
210
-60
32
120
390
480
0
50
75
25

F
Temperature
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Schematics of the typical process conditions
TRADITIONAL HOT MIX ASPHALT
5 FILLER 20 OC
90 AGGREGATE
DRYER
SILO
LAYING
MIXER
270-320 OF
300-350 OF
320 OF
390 OF
6 ASPHALT
WAM Foam ASPHALT MIX PROCESS
5 FILLER 20 OC
90 AGGREGATE
DRYER
MIXER
SILO
LAYING
260 OF
180-220 OF
225 OF
175-200 OF
1.8 SOFT 4.2 HARD COMPONENT
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1st WAM Foam 1999 (Norway)
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WAM Foam after two years
June 2001
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WAM Foam installation in Hot Mix Asphalt plant
2000
Original asphalt line
foam
mixer
New, 2nd asphalt line
8
Batch Plant Mixing Cycle 3.5 ton batch
25
5
15
0
55
Time (s)
35

• Aggregate gt 4 mm
• Soft Bitumen
• Aggregates 0-4 mm
• Hard Bitumen Foam
• Filler
• Discharge

Mixing
Mixing
-
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Field trials RV 120 September 2000
WAM Foam, DG 11, PG58-22 (80 pen) May 2002
Reference, DG 11, PG58-22 (80 pen)
May 2002
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Rut development on RV 120
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WAM Foam SMA 11, Track-paving on E6 - June 2002
Daily traffic 22000 vehicles - 65,2 kg/m2
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Adoption to Drum Mix Plant
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Asphalt Fume Emission monitoring
Emission measurements
Source Koenders et al, IRF 2004
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Fume emission measurement
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 !!
TPM
BSM
Source Koenders et al, IRF 2004
TPM Total Particulate Matter BSM Benzene
Soluble Matter
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CO2 emission during actual Production
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NOx and CO emission during actual Production
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Dust emission during actual Production
Production process
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Illustrations
230 ?F
311 ?F
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Illustrations
HMA
WAM Foam
vs.
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What has been we achieved with WAM Foam?

• 30 reduction in energy consumption, lower
  production costs
• 30 reduction in CO2-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 gt reduced oxidation/ageing
  of binder
• WAM Foam satisfies all Hot Mix Asphalt
  specifications according to Handbook 018
  (Norwegian Standard)
• Production Capacity maintained

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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 ?

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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