Emulsion Applications Promising Techniques in North America

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Emulsion ApplicationsPromising Techniques in
North America
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Overview of Promising Techniques in North America

• I Recycle Applications Cold Central Plant Mixes
  (CCPM) and Cold In Place Recycling (CIR)
• II Scrub Seals/Scrub Cape Seals
• III Warm Mix Asphalt
• IV High Float Emulsions
• V Reinforced Chip Seal
• VI Fog Seals
• VII Modified Slurry Seals
• VVIII Anionic Emulsions
• IX Trackless Tack Coats
• X Other

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I Recycle Applications

• Purpose
• Emulsions have been widely used in
  cold-in-place (CIR) recycle mixes on high and
  low traffic volume roads.
• With the increase in production of asphalt
  pavement millings or grindings, (recycled asphalt
  pavement or RAP millings) new technology
  emulsions are being developed to allow these
  millings to be used as aggregate for base courses
  and new pavement mixes.

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I Recycle Applications

• Types of emulsions
• Generally cationic mixing grade, may be
  performance enhanced with rejuvenators and
  polymer modifiers. Historically, emulsions for
  recycle applications contained solvents which
  improve wetting and bonding. New formulations
  can eliminate the need for solvent containing
  emulsions.
• Emulsions for recycle applications must be
  formulated to take into consideration the
  aggregate or RAP characteristics. Emulsion
  binder should be part of a performance designed
  mix.

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I Recycle (RAP) Emulsion Mix Central Plant
Mixing
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I Recycle (RAP) Emulsion Mix Central Plant
Mixing
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I Recycle (RAP) Emulsion Mix Central Plant
Mixing Lay-down on Compacted Base
Compacted AB
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I Recycle (RAP) Emulsion Mix Central Plant
Mixing Blade Laid
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I Recycle (RAP) Emulsion Mix Central Plant
Mixing Paver Lay-down and Compaction
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I Recycle (RAP) Emulsion Mix Central Plant
Mixing Windrow Lay-down, Paver Laid
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I Recycle Applications Cold In Place Recycling

• Cold-In-Place-Recycling Train

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I Recycle ApplicationsCold In Place Recycling
CIR Paving/Lay-down Equipment
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I Recycle Applications
Screened RAP millings for slurry mix applications
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I Recycle Applications
Use of RAP millings and specially formulated
emulsion for slurry surfacing
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II Scrub Seals and Cape Scrub Seals

• Purpose
• Seal oxidized or distressed pavements, seal fine
  cracks, provide new wearing course
• Types of emulsion
• Primarily cationic mixing grade, with or without
  rejuvenators or polymer modifiers, formulated to
  allow scrubbing action without breaking
  prematurely.

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II Scrub Seals

• Equipment
• Scrub brooms are added to chip seal lay-down
  equipment. Scrub brooms are designed to force
  emulsion (generally polymer modified) into
  micro-cracks in pavement surface.

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II Scrub Seal Placement
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II Scrub Drag Broom
Scrub broom sealing fatigue cracks
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II Scrub Seal Broom
Hydraulically operated scrub broom
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II Scrub Broom
Hydraulically operated, scrub broom designed to
eliminate excess emulsion at seal edge
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II Scrub Seal
Fine aggregate seal
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Scrub Cape Seal

• A scrub cape seal adds a surface treatment of
  slurry or micro-surfacing to lock in loose chip
  and provide a smooth wearing surface.
• The emulsion used for the slurry or micro is
  cationic, formulated to mix with additives such
  as cement or liquid retardants to control setting
  and breaking characteristics.

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The Concept of Pavement Preservation
The Concept of Pavement Preservation (Traditional
Approach)
3-5 yrs
5-10 yrs
New Life Cycle
Unrealistic Approach When (BudgetltNeed)
Overlay
(18.00 / SQ.YD)
Includes Grinding
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Mechanics
Zero Flexural Strength
Compression Side
Tension Side
Penetrates, rejuvenates and anneals to develop a
permanent chemical bond.
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System Differences
Center of Mass
Bridging Systems Hot Rubber Chip and Fabric
System boundary in red
Center of Mass
PASS System
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Re-Cap of the Scrub Cape Seal
Apply Scrub Emulsion
Apply, Roll Sweep the Chips
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The Cape can be either a Slurry Seal or a Micro
Surface. Both are a mixture of aggregate and
emulsion. A Micro surface differs in that the
cure time is chemically dependent and strength is
achieved almost immediately. A Micro surface is
generally A heavier application and therefore
cost about 20-30 more then a Slurry
Micro Box has augers to keep material moving
A Slurry Box has no augers
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Harrison Road PCI lt 15
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State Highway 58 Santa Margarita Ca
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Indio Ca. 1996
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Downtown Stockton E. Minor Blvd. Finished with
Type2 Micro
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III Warm Mix Asphalt

• Several technologies are being developed which
  employ emulsified asphalt as the binder in hot
  mix production.

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III Warm Mix Asphalt

• Emulsion for warm mix asphalt may be modified
  with polymers or plasticizers to facilitate
  compaction of warm mix.

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III Warm Mix Asphalt

• Conventional hot plants, using reduced
  temperatures can produce warm mix asphalt

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III Warm Mix Asphalt

• Extensive testing has been done on properties of
  warm mix asphalt demonstrating properties
  comparable to hot mix asphalt.

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Why Warm Mix Asphalt?

• Higher Temperature Trends
• Rising Energy Costs
• Odors
• Increased Activism

• IARC
• Kyoto Treaty
• Naphthalene PAH Emissions
• Particulate Emissions
• Regulatory Permitting

Lower Temperatures are Needed!
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What is EVOTHERM?
100F less than Hot Mix
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EVOTHERMEffective Temperature Range
Mixing Temperature
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EVOTHERMBenefits

• Decreased emissions at HMA plant
• Savings in energy
• Reduced exposure to fumes
• Lower odor
• Improved compaction
• Quicker return to traffic

• Extended haul distances
• Improved thin lift capabilities
• Higher RAP incorporation
• Expanded season
• Longer binder life
• Reduced binder requirement

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HERITAGE - MILESTONEIndianapolis, Jul. 6, 2005
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Stack Emissions
HMA emission normalized to 100
?34
?46
?55
?58
?63
?81
200 F Evotherm, 310F HMA control
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Fume Exposure vs. HMA
?41
Below Detectable Limits
?
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US Ozone Nonattainment
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RAMARA DEMONSTRATION Truck Samples
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NCAT Test Track
Mix Loaded out 130 PM next day
Mix Produced 700 PM
Mix held in silo at 240F overnight
Traffic Returned at 500 PM
Mix Placed at 315 PM
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NCAT Test Track
9.5 mm NMAS
10 Million ESALs
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HMA Control PG 67-22
Evotherm PG 76-22
Evotherm PG 67-22
19.0 mm NMAS w/ Evotherm PG 67-22
E9
2
600,000 ESALs
19.0 mm NMAS w/ Evotherm PG 67-22
2
Ndesign 80 for all mixes
N2
N1
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NCAT TEST TRACKPavement Densities
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NCAT TEST TRACK
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IV High Float Emulsions

• High float emulsions utilize chemistry (rosin
  acid salts) in the emulsifier or in latex
  additives, which creates a gel like structure in
  the emulsion. This structure is retained at
  elevated temperatures. The gel structure helps
  to ensure adequate film thickness in aggregate
  mix applications and resists bleeding in chip
  seal applications.

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IV High Float Emulsions

• High float emulsions may be cationic or anionic
  with or without polymer modification and solvents
• High float emulsions may be slow, medium or rapid
  setting
• Aromatic asphalts or solvent (diesel) containing
  asphalts are preferred for high float emulsions

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IV High Float Emulsions

• Anionic high float emulsions are generally used
  for mixing applications such as cold in place
  recycling. Anionic high floats can be
  manufactured from varying penetration grades of
  bitumen, using varying levels of polymer
  modification depending on desired residual
  performance properties

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IV High Float Emulsions

• Typical designations are HFE-150P or HFE-300P,
  where the number refers to the minimum
  penetration and the P designates polymer
  modification
• Polymer modification is usually measured by
  elastic recovery on residue by distillation

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IV High Float Emulsions

• Anionic high float emulsions can be formulated to
  be rapid setting
• An HFRS-2P designation indicates an emulsion with
  a pen on residue of 90-150 and a demulsibility of
  40 minimum

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IV High Float Emulsions

• Cationic, polymer modified high float emulsions
  are preferred for chip seal applications.
  Demulsibility for these applications is generally
  60 minimum.

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IV High Float Emulsions

• High float emulsions are applied using
  conventional bitumen application and mixing
  equipment

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V Reinforced Chip Seals

• Purpose
• Seal against ingress of moisture
• Provide a binder with improved engineering
  properties (tensile strength, elasticity through
  a wide temperature range, resistance to binder
  bleed through
• Provide new wearing surface.
• Types of emulsions
• Cationic or anionic, polymer modified
  rejuvenating, fiber modified

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V Reinforced Chip Seals

• Fiber reinforced chip seals
• Polymer modified chip seal binders

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V Reinforced Chip Seal Application Equipment

• Computer controlled distributor trucks
• Specialized pneumatic fiber feed distributor
  trucks

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V Fibre Reinforced Chip Seal Application
Equipment
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VI Fog Seals

• Fog Seals
• Purpose
• Fog seals prevent surface raveling of mixes
  (hot-mix, cold mix, slurry, micro) due to normal
  wear and aging, or chip loss on scrub or chip
  seals
• Rejuvenate existing surface
• Types of emulsions
• Primarily cationic, w or w/o rejuvenators, and
  polymer modifiers, usually dilute

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VI Fog Seals
Uses of Fog Seals - FHWA Emulsified
Sealer/Binder Study, Schofield, Larry, Principle
Investigator
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VI Fog Seals
Surface Treatments Frequently Fog Sealed to
Prolong Pavement Life FHWA Emulsified
Sealer/Binder Study, Larry Schofield, Principle
Investigator
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VI Fog Seal
Lightly sanded fog seal
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VII Modified Slurry Seals

• Slurry seals which are modified with ground tire
  rubber are now being widely used in the US.

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VII Rubber Modified Slurry Seal

• Emulsion is generally anionic
• Emulsion binder contains mineral fillers and
  thickeners to keep particulate rubber in
  suspension
• New technology which produces nano-particulate
  rubber is currently being developed. This
  technology will reduce the need for specialized
  rubber handling equipment

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VIII Anionic Emulsions

• While both cationic and anionic emulsions are
  used in North America, anionic emulsions have
  strongholds in several applications

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VIII Anionic Emulsions

• Seal-coating materials, which are formulated with
  mineral fillers and other additives which require
  a mixing grade emulsion, generally use an anionic
  slow setting emulsion (SS-1H) formulated to pass
  a cement mixing test.

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VIII Anionic Emulsions

• High float emulsions are generally anionic mixing
  grade emulsions
• Many emulsion mixes utilize anionic emulsions
  which tolerate variations in fines better than
  cationic formulations

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VIII Anionic Emulsions

• Some agencies in remote locations store anionic
  emulsions and use them as general purpose
  emulsions for mixing patching materials, tack
  coats, sand seals, etc..

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IX Trackless Tack Coats

• Purpose
• The development of trackless tack coats has been
  an attempt to diminish the pick-up or tracking
  of tack coats (by construction equipment) when
  tack coats are applied prior to paving.
• Trackless tack coats are also used to lock in
  chip on new chip seals and to seal RAP pavements

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IX Trackless Tack Coats
Trackless Tack Coat over chip seal
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IX Trackless Tack Coats

• Types of emulsion
• Trackless tack coats can be cationic or anionic
• Trackless tack coats are generally low pen, high
  softening point materials (15-20 pen, 75-85C SP)
• Trackless tack coats may be formulated with
  thermo-setting or thermo-plastic polymers to
  increase resistance to hot construction vehicle
  tires

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IX Trackless Tack Coats

• Equipment
• Most trackless tack coats are applied with
  conventional asphalt spread equipment
• Trackless tack coats may include a spray
  application of a breaking agent immediately
  following application of the tack coat. Equipment
  has been specially developed for this application.

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IX Tack Coat Application
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X Other

• New technologies include also alternatives to
  coal tar sealants which are being increasingly
  avoided due to the presence of polycyclic
  aromatic hydrocarbons (carcinogens) and
  emulsified petroleum resins for prime coating

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X Other
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Summary

• As asphalt prices continue to rise, more
  efficient and cost effective uses for emulsified
  asphalt are being developed
• Emulsion manufacturer organizations are an
  excellent source of contacts for information on
  new technologies being developed by member
  companies