An Introduction to Pavements

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An Introduction to Pavements

• Specific Emphasis on WSDOT Pavements

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Presentation for CEE 421

• Overview of Pavements
• Introduction to WSDOT Pavements
• Evolution and a Little History
• Pavement Design
• Pavement Rehabilitation
• Pavement Management
• Current Pavement Construction Issues

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Managing PavementsIs It Important?
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Early Roads
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Early Roads

• Roman Roads
• Early Asphalt Paving in Washington State
• Corduroy Road
• Bothell Road1912
• Sam Hill, Maryhill Roads, and Columbia River
  Highway1909 to 1920
• Opening of Pacific Highway1915
• Paving Sunset Highway (SR 2)1925

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A Really Early Pavement Roman Road in Pompeii
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Paving Riverside Ave Spokane, Washington in 1898
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Chehalis, Washington Corduroy Road
Construction 1910-1920
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Warrenite Bitulithic Paving Project (King
County) Bothell Road (Now SR 522Bothell
Way) May 1912
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Photograph date is May 14, 1912
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Sam Hill, Maryhill Roads, and Columbia River
Highway
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Biggs, Oregon
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Maryhill Museum
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Upper Loop Road 1909-1913
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Upper Loop Road (adjacent to US 97)
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1909-1913
Today
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Hand placing Macadam aggregate
Maryhill Road Construction 1909-1912
A real steam roller
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Maryhill Upper Loop RoadMacadam Pavement Core
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Blood Hound Guard DogLyle, Washington Convict
Labor Camp (So how did you think SR 14 was
originally built?)
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Restored Columbia River HighwayHood River, Oregon
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This section was constructed ? 1920
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Opening of Pacific Highway January 29, 1915
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Paving the Sunset Highway
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Paving the Sunset Highway West of Spokane 1925
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Paving the Sunset Highway with PCC--1925
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Completed Segment of Sunset Highway
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Current Condition of Portion of Sunset Highway
Paved in 1919
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Date Stamp
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Road Vehicles and Construction EquipmentPast to
Present
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• Logging Truck in Western Washington--1918
• Solid Rubber Tires
• Chair Drive

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1923 Kenworth with Solid Rubber Tires
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1926 Kenworth Truck with Pneumatic Tires
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End Dump
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Flowboy
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Belly Dump
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Steam Roller Pulling Aggregate Carts Seattle
1910-1920
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Blaw-Knox MC-30
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Roadtec Shuttle Buggy
Photo courtesy of Roadtec
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Pavement Design
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Flexible Pavements
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Trinidad Lake Asphalt
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Asphalt Concrete and Asphalt Binders
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Bituminous Surface Treatment Flexible Pavement
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Flexible Pavement Design Procedures

• AASHTO 86/93
• Asphalt Institute
• Mechanistic-Empirical
• Other

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AASHTO

• Founded 1914
• AASHO became AASHTO in 1973
• Milestones
• Development of national standards and
  specifications
• Nationwide route numbering system
• AASHO Road Test (1955)
• NCHRP (1962)
• SHRP (1987)

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Empirical Design Approach

• Based on results of experiments or experience
• Scientific basis not established
• AASHTO 86/93 an empirical design method
• Refer to AASHO Road Test

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Typical Loop Layout--AASHO Road Test Loop 5
Single Axles 22.4 kips, Tandems 40 kips Loop 6
Single Axles 30.0 kips, Tandems 48 kips
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Empirical ApproachAASHTO Flexible Pavement
Performance Equation

• log10 W18
• (ZR) (S0) (9.36)(log (SN 1)) - 0.20
• ?log10?PSI/(4.2-1.5)/0.40 1.094/(SN
  1)5.19 ?
• (2.32) (log10MR) - 8.07

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Mechanistic-Empirical Approach(for design and
analysis)

• Mechanistic Determine stresses, strains, or
  deflections at critical locations in a pavement
  structure.
• Empirical Relates stresses, strains, or
  deflections to pavement performance. Sometimes
  referred to as Failure Criteria or Transfer
  Functions.

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• M-E design process requires
• Material properties of each layer (Ei, ?i)
• Thickness of each layer (hi) and load (P, a)

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Fatigue Cracking and Nfatigue
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Total Pavement Rut Depth and Nrutting
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Design Inputs

• Traffic Loading and the Design Period
• Materials Characterization
• Climate Characterization or Conditions
• Life Cycle Cost Analysis

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Traffic Loading

• Equivalent Axle Loads (18,000 lb (80kN) single
  axles)ESALs or E80s
• Approximate estimate
• Fourth Power Law axle wt/18,0004

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WSDOT Design Periods

• New Designs/Reconstruction
• National Highway System 40 years
• Non-Federal Aid 40 years unless ESALS less than
  100,000 per year
• Rehabilitation
• AC Overlays 15 years

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Material Characterization

• Asphalt Concrete
• Marshall Stability
• Hveem Stability
• Elastic Modulus
• Unstabilized Aggregate (Base and Subbase Courses)
• California Bearing Ratio (CBR)
• R-value
• Elastic Modulus
• Subgrade
• CBR
• R-value
• Elastic Modulus

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Typical Flexible Designs
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Flexible Pavement Design Procedures
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COST 333 Participating Countries

• Austria
• Belgium
• Switzerland
• Germany
• Denmark
• Spain
• Finland
• France
• UK
• Greece

• Greece
• Croatia
• Hungary
• Ireland
• Iceland
• Netherlands
• Norway
• Portugal
• Romania
• Sweden
• Slovenia

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European Standard Axle Loads
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European Asphalt Concrete Thicknesses (20
Countries)

• Comments
• E80s 10 million
• CBR 5

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Comparison of Asphalt Concrete Thicknesses (mm)

• Comments
• Minn 75 mm if Deep Strength design
• EU thickness represents the mean of 20 countries
• E80s 10 million
• CBR 5 to 6

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Asphalt Concrete Thicknesses (mm) for Three
Levels of E80s
Note Various levels of reliability influences
thicknesses.
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Comparison of Total Pavement Thicknesses (mm)

• Comments
• Tx -200mm if delete lime treated subgrade
• R 85 Wa
• R 95 Tx, RSA
• E80s 10 million
• CBR 5 to 6

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Rigid Pavements
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Rigid Pavement Design

• AASHTO 72/81
• AASHTO 86/93
• Portland Cement Association
• Mechanistic-Empirical
• Other

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Typical Rigid Designs
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Rigid Pavement Design Features
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Typical Rigid Pavement Designs
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15th Avenue NE
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Jointed Doweled PCC Paving Dowel Bars in Cages
Ready for Placement of PCC US 395
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PCC Construction US 395
Construction of a Doweled Construction Joint
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California Profilograph is used to check pavement
smoothness following construction
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PCC Contraction JointsUS 395
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Illustration of Contraction Joint Crack and
Aggregate Interlock
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Tie Bars for Joining to Adjacent Lanes (I-90
Spokane)
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Pavement Rehabilitation
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Asphalt Concrete OverlayUS 2
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1992 Dowel Bar RetrofitI-90
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Dowel Bars Before Placement of Patch Material
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Pavement Distress
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Longitudinal Cracking
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Fatigue Cracking (Alligator Cracking)
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Fatigue Cracking (Alligator Cracking)
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Pothole
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Transverse Cracks
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Rutting
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Panel Cracks
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Faulting of Transverse Joints
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Current Pavement Construction Issues
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The Problem

• Localized spots of coarse surface texture
• Premature failure due to fatigue cracking,
  raveling, and moisture damage

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End Dump/No MTV
Route SR-203 Section King/Snohomish Line to
SR-2 Binder PG 64-22 Mix Class A Haul Time
30 minutes Haul Length 18 miles Plant Temp
290F Mat Temp 255F Comments Thermal
differential of 140 degrees between crust and
internal mix.
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End Dump/No MTV
Route SR-203 Section King/Snohomish Line to
SR-2 Binder PG 64-22 Mix Class A Haul Time
30 minutes Haul Length 18 miles Plant Temp
290F Mat Temp 255F Comments Temperatures
and corresponding densities.
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Paving Industry
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Hot Mix Asphalt Industry

• Miscellaneous hot mix facts and figures for the
  US
• 600 million tons of asphalt concrete produced
  during 2006 with a value of 20 billion
• Produced by 1,100 producer firms in 3,600 plants
  and placed by several thousand paving contractors
• 500 million tons of crushed rock, sand, and
  gravel supplied to HMA industry mined and
  processed in 9,000 quarries and sand and gravel
  operations
• More than 36,000 agencies that specify HMA.

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Hot Mix Asphalt Industry (cont.)

• More than 80 refineries in US and Canada produce
  liquid asphalt cement with additional asphalt
  cement being imported. Total asphalt cement sales
  estimated to be 30 million tons with a value of
  4 billion.
• National Asphalt Pavement Association (NAPA)
  represents the HMA industry at the national
  level. The Asphalt Institute represents the
  liquid asphalt cement suppliers at the national
  and state levels.