Warm Mix TechnologyThe Canadian Perspective

J.Keith Davidson P.Eng.McAsphalt Industries Limited

Toronto Ontario Canada

CUPGA – 2007 – Niagara Falls

Agenda

• Background

• Introduction

• Processes

• Environmental Data

• Other Benefits

• The Future

Background

• 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

– 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

• 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

• 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

• 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

• 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

• 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

• 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

• 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?