Warm MixAsphalt
NAPA Strategic Goal:
Reduce Emissions,
Fumes and Odors
Strategies
• Engineering Controls
• Best Management Practices
• Low Fuming Asphalts
• Warm Mix Asphalt
Hot Mix Asphalt 275-325oF
Cold Mix Asphalt 60oF
Warm Mix Asphalt 250-275oF
What is Warm Mix Asphalt?
Advantages of Lower Temperatures
• Lower fumes and emissions
• Lower energy consumption
• Lower plant wear
• Decreased binder aging
• Early site opening
• Cool weather paving
• Compaction aid for stiff mixes
• Improved working conditions
Goals for Warm Mix Asphalt
• Use existing Hot Mix Asphalt plants
• To meet existing standards for Hot MixAsphalt specifications
• Focus on dense graded mixes forwearing courses
• WMA quality = Hot Mix Asphalt quality
Available WMAAvailable WMA
TechnologiesTechnologies
Processes include:Processes include:
–– WAM Foam – Shell/WAM Foam – Shell/KoloKolo VeidekkeVeidekke
–– Zeolite – Eurovia/Hubbard ConstructionZeolite – Eurovia/Hubbard Construction
–– SasobitSasobit – – SasolSasol Int./Moore and Int./Moore and MungerMunger
–– Evotherm Evotherm - - MeadWestvacoMeadWestvaco
–– New processesNew processes
Warm Asphalt Mixes by adding
aspha-min®, a synthetic zeolite
Aspha-Min®
• Zeolites
– Framework silicates have vacant spaces in
their structures that can trap water
• Spaces interconnected forming long widechannels
– Can lose and absorb water without damage to crystal structures
• The trapped water is driven off by heat
Aspha-Min®
• Add 0.3 percent by mass to mix
– Water is released at high temperatures
• 185 to 360o F
• Foams the asphalt
– Reduces viscosity
• Reported by Eurovia
– 54o F reduction
– Fuel savings of 30% Aspha-Min® is a fine white powder
Production of warm asphalt
mix
•No modifications to mix design.
•Increase workability at low temperatures.
•Mixing temperature between 130 and 145°C
(266 to 293°F).
Aspha-Min®
Aspha-min Field SectionsAspha-min Field Sections
•• Paving project in Germany – Fall 2003Paving project in Germany – Fall 2003
•• Orlando Paving Company – First U.S.Orlando Paving Company – First U.S.trial February 2004trial February 2004
•• World of Asphalt – March 2004World of Asphalt – March 2004
•• Charlotte, NC – Blythe Construction –Charlotte, NC – Blythe Construction –September 2004September 2004
Polymer Modified Warm AsphaltPolymer Modified Warm Asphalt
with Zeolite at 250 Fwith Zeolite at 250 F
4 passes of Rubber Tire,
followed by 4 vibratorypasses, followed by static
finish roller
94% Gmm
55 F Air Temp.
Seeing is Believing!Seeing is Believing!
Hot Mix 314 F Warm Mix 254 F
138.1 pcf 138.5 pcf
Sasobit®
• Product of– Sasol Wax GmbH (Germany)
• Fischer-Tropsch parrafin wax– Fine crystalline long chain aliphatic
hydrocarbon
– Produced from coal gasification
• Available in– Flakes or powdered form
– 2, 5, 20, and 600 kg bags
SasobitSasobit
temperature
vis
co
sit
y
Organic additives
Bitumen
Additive
How organic additives work
Wheel tracking tests of binder course asphalt (Hamburg device)
0
1
2
3
4
5
6
7
50/70 50/70 + 2 % FT-
paraffin
50/70 + 3 % FT-
paraffin
50/70 + 4 % FT-
paraffin
50/70 + 5 % FT-
paraffin
rut
de
pth
[m
m]
Influence of organic additives (FT)
Organic additives
Wheel tracking test (Hamburg device)with growing %-FT-paraffin
Asphalt Case Studies presented at NAPA Convention Feb 17, 2005
Frankfurt AirportFrankfurt Airport
• Asphalt mixture laid at low temperature
• Better compactability
• Increased resistance to deformation athigh temperatures
Asphalt Case Studies presented at NAPA Convention Feb 17, 2005
Frankfurt AirportFrankfurt Airport
• Bear heaviest aircraft in 2-3 hours
• Reduced cooling, key to 300-step project
EVOTHERMEffective Temperature Range*
Hot Mix: 150oC (302oF)
Temperature Difference:
45-90oC (81-162oF)
EVOTHERM: 60-105oC (140-221oF)
*Mixing Temperature
EVOTHERM OverviewTechnology Highlights
• Innovative chemical additive technology• Chemical structure developed & optimized for warm mix performance
• Molecular structure imparts coating, workability, strength, and adhesion
• Dispersed Asphalt Technology (D.A.T.) delivery system
• Mix & compaction temperatures as low as 60oC (140oF)
• Openly available to end users; no licensing
EVOTHERM OverviewProduction
• Mix & compaction temperatures as low as 60oC (140oF)
• No plant modifications required
• No unit operations problems encountered
• Reduced dust generation
• Siloable mixes
EVOTHERM Field Trials
Immediate release to traffic
SHRP and conventional
mixes, using standard production, laydown, &
compaction methods
NCAT Study on Warm Mix Asphalt
Voids in the mix versus temperature via vibratory compactor (PG 64-22 mixes)
0.0
2.0
4.0
6.0
8.0
300F 265F 230F 190F
Compaction Temperature
VT
M
GRANITE LIMESTONE
0.0
2.0
4.0
6.0
8.0
300F 265F 230F 190F
Compaction TemperatureV
TM
HMA EVOTHERM■
NCAT Study on Warm Mix Asphalt
Resilient moduli of granite / PG 64-22 mixes were comparable (voids notwithstanding)
0
200
400
600
300F 265F 230F 190F
Compaction Temperature
HMA EVOTHERM■
NCAT Study on
Warm Mix Asphalt
APA and Hamburg results were similar for HMA and EVOTHERM granite / PG 64-22 mixes
0.00
5.00
10.00
15.00
20.00
25.00
300F 265F 230F 190F
Compaction Temperature
Ru
t D
ep
th, m
m
APA Rutting Depths Hamburg
0
2
4
6
8
10
12
mm
@ 1
0K
cycle
s
HMA EVOTHERM■
Tested at 40oC Tested at 50oC wet
NCAT StudyNCAT Study
•• Evaluate Warm Asphalt TechnologiesEvaluate Warm Asphalt Technologiesfor U.S. Paving Practicesfor U.S. Paving Practices–– High productionHigh production
–– Rapid Turn-over to trafficRapid Turn-over to traffic
•• Potential ConcernsPotential Concerns
–– “Curing” Time“Curing” Time
–– Increased Potential for Moisture DamageIncreased Potential for Moisture Damage
–– Binder effectsBinder effects
Project PartnersProject Partners
NCAT
NAPA/State Associations
Shell/Kollo Veidecke
Eurovia/Hubbard
Sasol/Moore and
Munger
FHWA
?
MeadWestvacoAsphalt
Innovations
Top Related