Surface Pavements

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Surface Pavements Past, Present Future
Vince Aurilio Ontario Asphalt Sales
Manager Bitumar Inc.
2006 CUPGA MEETING Charlottetown, Prince Edward
Island
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The Modern Asphalt Pavements - 1905

• Richardson recognized the importance of selecting
  the right materials
• Documented principles of HMA design including VMA
  and air voids
• Had a test to determine the optimum asphalt
  cement content
• Applied to sheet asphalts (hot sand asphalt mix)

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The Warren Bitulithic Patent

• Basically the application of the first large
  stone mixes
• Performed better than thick sheet asphalt, which
  at the time tended to rut when subjected to
  slow-moving carts with narrow steel-rimmed wheels
  (NCAT)
• Patent expired in 1920 but litigation (the so
  called Topeka decree of 1910) of the time
  probably set the path for dense graded mixes

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So, Why Have Things Changed?

• Performance Problems
• Traffic
• Safety
• Advancements
• Better Materials
• Improved Construction Equipment
• Better Construction Practices

Changes Made in Response to Need
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Rutting in the 80s
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Traveling by Automobile in 1911
Source UW Libraries
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The Challenge
Stress

• Increased truck traffic
• Increased allowable maximum loads
• Increased tire pressures

Slow moving or standing loads subject pavements
to higher than normal stress conditions.
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Back to the Future

• From Recipe Mix Designs in the 20s
• Move to Marshall after WWII
• SHRP Superpave in the 90s

Continuous Shift in Technology - Evolution
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1990 European Asphalt Study Tour

• Asphalt Pavement Mixtures
• Stone Mastic Asphalt
• Porous asphalt
• Modified Binders
• Laboratory Equipment
• Mix Design Equipment
• Laboratory Compaction
• Rut Tester
• Innovative Contracting Practices
• Lane Rental
• Contractor Warranties/Guarantees
• Research

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The Big Change?

• Over last 10-15 yrs
• Move to End Result Specifications
• More robust mixes e.g. Superpave
• Increased focus on volumetrics, in the lab and at
  the plant
• Increased use in modified asphalts
• Decreased or limiting use of natural sands
• Better laydown and compaction equipment/practices

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Superpave System
2. Design Aggregate Structure
1. Materials Selection
TSR
3. Design Binder Content
4. Moisture Sensitivity
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Superpave Asphalt Binder Specification

• Grading System Based on Climate

PG 58-28
Performance Grade
Average 7-day max pavement design temp
Min pavement design temp
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Binder Grade is a function of environment and
traffic level
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Superpave Binder Equipment
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Aggregate

• Consensus Properties
• coarse aggregate angularity
• fine aggregate angularity
• flat, elongated particles
• clay content

Sand Equivalent
51 FE Calipers
FAA Apparatus
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Project 9-29 First Article Simple Performance
Test Systems
INTERLAKEN
SHEDWORKS
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Surface Mixes - State of the Practice

• Dense Graded Mixes
• Fine vs. Coarse
• Premium Mix Types
• Superpave
• GAP Graded Mixes - SMA
• Improved Performance (e.g. rutting, fatigue)
• Reduced Noise
• Optional Open-Graded Friction Course
• Improves Skid Resistance
• Reduces Splash and Spray (and Noise)
• Surface Water Still Drains to Sides

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SMA
Stone Skeleton
Stones

Filler Sand Bitumen
S TONE M ASTIC A SPHALT
Mastic
Fibers
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Windsor SMA - Final Product
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European Approach - UK
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European Two-layer Concept
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The OGFC Absorbs Part of the Sound Energy
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OGFC GRADATIONS
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Design Principles

• Emphasis on high air voids (13-20)
• as designed and constructed
• Aggregate size (3/8 to ½ inch NMAS)
• large pore spaces, less clogging
• Lift Thickness of 1.5 2.0 inches
• accommodate larger aggregates, greater volume of
  void space within mix
• Performance Graded (PG) binders
• polymer modifiers
• fiber additives

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Asphalt Pavement Americas Recycling Leader

• Asphalt pavement is Americas most recycled
  product. Period.

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How much asphalt pavement is recycled?

• Tonnage 73 million metric tons (80.3 million
  tons)
• Rate 80 of the asphalt pavement removed during
  widening and resurfacing projects
• Federal Highway Administration

• Compared with
• Only 28 of post-consumer goods in the municipal
  solid waste stream
• U.S. Environmental Protection Agency

(1997 Data)
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Annual Recycling Tonnage
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Processing RAP
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Improved guidelines for RAP

• FHWA Mix ETG developed guidelines based upon
  consensus and limited testing (?15, 16-25,
  25).
• NCHRP 9-12, Incorporation of RAPin the
  Superpave System
• Guidelines for Incorporating RAP in Superpave
• Use of RAP in Superpave Technicians Manual

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Environmental Benefits

• Other recycled products are used in making
  asphalt pavement
• Old tires
• Slag aggregate
• Roofing shingles
• Foundry sand

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Development of SuperThin Mixes in NY

• Want to pave Thin Overlays
• Superpave did not address Maintenance needs
• HMA alternative to liquid preventive maintenance
  items
• Micro-surfacing
• Curing time traffic delays
• Specialized Equipment
• Paver-Placed Surface Treatment (e.g. Novachip)
• Specialized equipment
• Vendor availability Region 10, 11
• Proprietary item
• Towns and Counties
• Familiar with 6F and 7F dont want to use 12.5
  or 9.5 mm mixes

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Production SummaryRt. 17 Project
49 1As 51 Sand 1 Mineral Filler 6.7 AC
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Perpetual Pavement Concept
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Top-Down CrackingAsphalt Pavements gt 150 mm
50 mm
150 mm
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Don Valley Parkway
Perpetual Pavement Award Winner
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End Load Segregation
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Comparison of Smoothness(1997 Vs. 1999)
1997
1999
Excellent
Acceptable
Fair
Poor
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A
Compact asphalt paver

• The

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Compact-asphalt paving on the A 20
(Germany) German Government paving 12 km on the
A20 near Berlin. On this project they used a
Compact paver F 360 CS/AM 300 of DYNAPAC with a
material transfer vehicle MF 300. The paving
width is 10,5 meters.
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Production 2200 meters/day About 7000 tons of
asphalt/day
SMA
Binder layer
14 cm base layer
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SMA
Binder layer
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A
Two asphalt layer Pavers

• The

• thinner surface layers are possible
• better quality of the thin surface layer
• better heat capacity
• better compaction
• better bond between top layers

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Rollpave
Rollpave

• Dutch Innovation Program Roads to the Future
• June 2006
• 500 m Test section on Motorway A35
• Prefabricate asphalt layer
• Rolled out as a carpet

• Dutch Innovation Program Roads to the Future
• June 2006
• 500 m Test section on Motorway A35
• Prefabricate asphalt layer
• Rolled out as a carpet

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A

• The

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Thats All Folks!