Transcript J.Keith Davidson – Warm Mix Technology. The Canadian Perspective

Warm Mix Technology
The Canadian Perspective
J.Keith Davidson P.Eng.
McAsphalt Industries Limited
Toronto Ontario Canada
CUPGA – 2007 – Niagara Falls
Agenda
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Background
Introduction
Processes
Environmental Data
Other Benefits
The Future
Background
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Kyoto Accord
Energy prices increasing
Stricter environmental rules
Emission reductions
Introduction
• 6 main processes
– Aspha-min
– Sasobit
– Wam Foam
– Low Energy asphalt
– Astec Process
– Evotherm
Aspha-min Process
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Eurovia of Germany
Synthetic zeolite (Sodium Aluminum Silicate)
21% water/ white powder
Added to mix at same time as binder
Water spray created slowly which foams binder
Gives increased workability and allows coating at
lower temperature
– Typically 0.3% added to mix
– Temperature drops up to 30 - 35°C
Sasobit Process
– Sasol of South Africa
– Paraffin wax made from Fischer-Tropsch process
– Different cystalline structure compared to
conventional waxes
– Melts into binder at 110°C
– Reduces viscosity of binder
– Temperature reductions of 10 to 40°C
– Typically 1 - 2% added to binder
– Improves rutting resistance
Wam Foam Process
– Shell has operates the process
– 2 binder component system
– Soft binder and a foamed harder bitumen
– Soft binder mixed at 110°C– full coating
– Hard binder foamed into soft binder coated
particles
– Blend of hard and soft binder critical to process
Low Energy Asphalt Process
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Coarse aggregate heated and coated
Fine aggregate added at ambient temperature
Additives added to AC
Foaming action creates lower temperatures
Maintains workability and compaction
100°C laydown temperatures typical
Astec Process
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Foaming kit on double barrel drum plant
10 nozzle system (individually controlled)
Up to 500 tph (50 tph/nozzle)
550 US gal water system (skid mounted)
Reduction in energy usage
• Mixing temperature reductions of 30°C
Astec Process
Evotherm Process
– Non-proprietary technology based on a
chemical package
– Additives to improve coating, workability,
adhesion and emulsification
– Two methods of production
• A high residue emulsion (67-69% PGAC)
• DAT Concentrate (Dispersed Asphalt
Technology)
– Injection system
Process Trials
• 5 Processes in Canada being evaluated
• Aspha-min
• Sasobit
• Wam Foam
• Astec Process
• Evotherm
Aspha-min
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Trials placed in 2005 & 2006
Construction DJL has been the contractor
Working with Eurovia
Various PG grades used
MTQ Project – 2006 (PG 64-34)
Sasobit
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In its infancy here
Bitumar (AC Supplier)
Working with Sasobit Consultant
2 trials
– City of Toronto – 300t
– City of Ottawa – 3000t
Wam Foam
• 1 trial in City of Calgary – 2005
• LaFarge retrofitted a plant to produce
• Placed in August in new subdivision
– Covered with surface mix
– Performed well
• Mixing and compaction temperatures
lowered significantly
ASTEC Process
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5 trials this year
New plant (double barrel green)
Can retrofit existing drum plants
Energy reductions (10-15%)
Emissions reduction
Compaction temperatures 100°C range
Evotherm
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3 trials in 2005 – 1700 tonnes
1 Trial in 2006 – 1250 tonnes
7 Trials in 2007 – 9200 tonnes
Various PG grades used
Evotherm Emulsion - 2007
Warm Mix
Hot Mix
Evotherm DAT Process
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Concentrated solution of Evotherm
Pumped, metered & injection system
Injected into pugmill as AC is added
Chemical into AC
Creates foaming and disperses chemical
Evotherm DAT Process
Environmental Data – Warm Mix
• Definite reductions in Greenhouse gases
– reductions up to 60%
• Reductions in fuel usage
– 10 – 50% reduction
• Reduction in fumes at paver
– Up to 50%
Other Benefits of Warm Mix
• No mix design issues (Marshall or
SuperPave or Hveem)
• Physical properties equivalent to HMA
• Performance properties equivalent to HMA
• Reduced age hardening through plant
• Longer haul distances
• Excellent compaction
The Future
• Tendering of projects
• Continued expansion of usage of warm
mix
• High RAP mixes
Way of the future in our industry
Thank You
Questions?