Rehabilitation of 24th Street in Ogden, UT

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Rehabilitation of 24th Street in Ogden, UT
2
Introduction

• State or Local Transportation Agencies when faced
  with deciding what to do with deteriorated
  Portland Cement Concrete Pavements (PCCP)
  typically have two choices

• 1. Replace with new PCCP.
• 2. Rehabilitate with a Hot Mix Asphalt (HMA)
  Overlay.

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Rehabilitation Techniques

• Place thick (4 inches) HMA overlays.
• Use a stress absorbing membrane interlayer
  between the PCCP and the HMA overlay.
• Place nonwoven geotech fabrics between the PCCP
  and the HMA overlay.
• Use woven geotech fabrics or geo-grid material
  between the PCCP and the HMA overlay.
• Crack Seat PCCP and place HMA overlay.
• Rubblize PCCP and place HMA overlay.

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Conventional Practice Requires Moderate to
severe distresses to be repaired full depth or
replaced prior to construction
Patch Deterioration
D-Cracking
Transverse Joint Spalling
From SHRP P-338 Distress Manual
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Factors Affecting Rehab Treatment Performance

• Existing condition of the PCCP.
• Construction Procedures.
• Weather Conditions.
• Traffic Loading.

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The Problem Reflective Cracking
Before
Conventional HMA Overlay6 months later
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Strata Reflective Crack Relief System (RCRS)
offers new approach
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Strata Reflective Crack Relief System (RCRS)

• Developed by Koch Pavement Solutions to address
  the problem of reflective cracking in HMA
  overlays when placed over PCCP .
• RCRS consists of a highly elastic, impermeable
  hot mix interlayer coupled with an elastomer
  modified HMA overlay.
• HMA overlay is designed to be compatible with the
  interlayer as well as meet the demands of local
  traffic.
• Interlayer is composed of a premium
  polymer-modified asphalt binder at a high asphalt
  content in a dense fine aggregate mixture.

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Strata Reflective Crack Relief System (RCRS)
Cont.

• Performance-based specification is used to design
  the mix and is certified using the Flexural Beam
  Fatigue (AASHTO TP-8) Test.
• Elastomer Modified PG binder at 98 reliability
  is specified in the HMA overlay.
• Both the interlayer and the overlay are placed
  with conventional lay down equipment.

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Strata Reflective Crack Relief System (RCRS)
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24th Street Existing Pavement Condition
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GPS Survey Used to Define Locations of Existing
Pavement Distresses
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Distress Location Reference System A Street to
B Street (Control Section)
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Lineal Feet of Cracking in Control Section
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Distress Location Reference SystemB Street to C
Street (Test Section)
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Lineal Feet of Cracking in Control Test Sections

•  

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Pavement Design

• Pavement Design Objectives
• Provide structural capacity for 20 years
• Minimize reflective cracking.
• Work within budget and profile constraints.
• Projected traffic loadings
• 3 million ESALs for 10 year design period.
• 7 million ESALs for 20 year design period.

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Pavement Design

• Pavement Layer Thicknesses
• Hot Mix Asphalt Overlay
• Plant Mix Seal Coat 30 mm
• Hot Mix Asphalt 80 mm
• Stress absorbing membrane (Strata Reflective
  Crack Treatment 1 nominal)
• Rotomill 120 mm below final pavement surface at
  centerline to provide a 2 percent cross slope.

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Pavement Design

• Lane Widening
• Material Thicknesses
• Plant Mix Seal Coat 30 mm
• Hot Mix Asphalt 150 mm
• Untreated Base Coarse 180 mm
• Granular Borrow 300 mm
• AASHTO SN 4.4

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Pavement Design Information

• Structural value

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Typical Cross Section Control Section
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Typical Section DetailsTest Sections
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Design Performance Based Specs Hveem Stability

• Resistance to Rutting During Construction
• 18.0 minimum Hveem Stability

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Interlayer Materials Specifications

• Liquid AC Binder
• Performance Graded (PG) to meet service
  conditions.
• Elastic Recovery 45 min. _at_ 25 degrees C
• Separation 6 degrees C max. after 48 hrs.
  (ASTM-5976)

• Fine Aggregate Requirements
• Sand equivalency 45
• Crushed Natural Sand

Gradation Sieve Passing 3/8 inch
(9.5 mm) 100 No. 4 (4.75 mm) 80 100 No.
8 (2.36 mm) 60 85 No. 16 (1.18 mm) 40
70 No. 30 (600 mm) 25 55 No. 50 (300 mm)
15 35 No. 100 (150 mm) 8 20 No. 200 (75
mm) 6 14
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Design Volumetrics Specifications
Criteria for 9.5mm mixture, medium traffic.
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Performance Based Design Specs AASHTO TP 8
Flexural Beam Fatigue

• Interlayers resistance to repeated bending
• Data of cycles to failure
• loss of strength
• Test simulates PCC joint movement

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Design Performance Based Specs Fatigue

• Flexural Beam Fatigue Device, AASHTO TP-8
• Tests mixs ability to withstand repeated bending
• Data number of loading cycles to failure (loss
  of strength)
• Run at 10x typical strain (deformation) to
  simulate PCC joint movement

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Performance Based Spec Highly Crack Resistant
AASHTO TP-8, at test temperatureTest temperature
determined by project climate
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Pavement Mix Design Procedure Results

• Strata interlayer exceeded the performance based
  specification minimum requirement of 100,000
  cycles at 2000 microstrain (??) using the
  Flexural Beam Fatigue (AASHTO TP-8) Test.
• Strata interlayer mix used on this project
  exceeded 200,000 cycles.
• Strata interlayer had Hveem Stabilometer value of
  20.8.

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Construction Specifications

• Specified temperatures
• Mixing 320 to 340 F
• Laydown 300 to 320 F
• Compaction 290 to 310 F
• Density 96 min. of Max. Specific Gravity -Gmm
• Test strip required
• Surface preparation
• QC on mix binder required.

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Rehabilitation Work

• Rehabilitation work began with widening of 24th
  Street and adding new curb and gutter and
  sidewalks on both sides of the street.
• Existing pavement was milled to provide a uniform
  cross slope of two percent (2). This resulted
  in varying depths of the existing old HMA overlay
  left in place.
• During construction, traffic was diverted to the
  westbound lane while the eastbound lane was
  milled. Construction process was reversed and
  westbound lanes were milled with traffic diverted
  to the eastbound lanes.

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Rehabilitation Work Cont.

• HMA leveling course was placed on the milled
  surface of the test section to provide a uniform
  surface for the placement of the RCRS interlayer
  and the new pavement.
• Leveling course extended from the West end of
  the project to station B-4 on the east.
• Leveling course extended 12 feet on either side
  of the street centerline with a nominal depth of
  one half inch (0.5) to three-fourths inch
  (0.75).

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Construction Widening Process
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HMA Leveling Course - East-Bound Lane
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Construction of Pavement Interlayer

• After preparation of the existing pavement, the
  Strata RCRS was placed with a conventional HMA
  laydown machine.

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Placement of Strata Interlayer
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Density Testing/Temperature Measurement
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Strata Reflective Crack Relief System (RCRS)
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Interlayer after Five Days Traffic
Strata Interlayer is designed to take traffic for
several days before overlay is placed.
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Laydown of HMA Overlay

• Conventional
• Laydown
• Equipment.
• Asphalt Cement
• in overlay selected to
• give 98 reliability
• using LTPP Binder
• Selection Procedure.

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24th Street after Placement of Open Graded
Asphalt Friction Course
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Performance Evaluation Plan

• Document Existing Pavement Conditions
• Map All Pavement Distresses Locations
• Conduct Bi-annual Pavement Condition Surveys.
• Monitor and Document Traffic Conditions Yearly.

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Data Collection

• Extensive pavement condition data was collected
  to assess and document the original street
  condition after milling. This information
  includes
• A base map of the new roadway alignment.
• A map of existing pavement cracks.
• Core samples taken at five locations after the
  Strata interlayer and before the HMA overlay and
  Plant Mix Seal were constructed.
• Field notes and photographs taken during
  construction.

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GPS Monitoring Process
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Base Map

• The base map was produced by the Utah T2 Center
  using Global Positioning System (GPS) technology
• Map shows the new curb line of the roadway.
• Condition of the street was recorded by mapping
  the cracks in the existing pavement after the
  surface had been milled and before the level-up
  course was placed.
• A line was surveyed for every major transverse
  crack, longitudinal crack, block cracking, and
  utility cut.
• In addition, a point feature was taken for each
  pothole found in the existing pavement.

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Additional Information Collected

• The following additional information was
  collected for each distress type to determine
  its location, extent, and severity
• A letter coding system was used to identify each
  type of distress and its location within each
  section.
• Distress type.
• Date information collected.
• Crack width.
• The pavement area affected by spalling,
  secondary cracking, fatigue, etc.)
• A digital photograph of every crack

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Distress Map (Control Section)
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Distress Map (Test Section)
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Transverse Cracking
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Pothole
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Utility Cut
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Core Samples

• Before overlaying the Strata with the HMA, five
  (5) core samples were extracted and tested by
  Granite Construction.
• Stratas average specific gravity in the cores
  was 2.285 with a standard deviation of 0.043.
• Average percent compaction was 96.4 with a
  standard deviation of 1.8.
• Core number three was significantly thinner than
  the other cores and had a lower density. This is
  likely due to damage sustained during coring and
  extraction.

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Core Samples
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24th Street, Ogden, UtahConstructed in 2002
Strata treatment
Surface before Strata treatment
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Condition Survey and Surface Evaluation

•  Periodic condition surveys surface evaluations
  will be made to determine the effectiveness of
  the Strata system in delaying reflective cracks.
  
• Original condition of the pavement has been
  assessed by mapping the cracks in the original
  surface of the street.
• Bi-annual surface condition surveys will be
  conducted and will include mapping any new cracks
  that appear using the same GPS technology so
  that any reflective cracking can be determined.

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Condition Survey Surface Evaluation

• Future distress maps will be compared to the
  original condition map to assess whether new
  cracks are due to reflective cracking through the
  Strata system.
• Information such as the location of the crack,
  type of distress, date, width of the crack, and
  the width of pavement affected by the crack will
  be collected for each new crack.
• A digital picture of every new crack will be
  taken. Any deformation or abnormality of the
  pavement will be noted and a digital photograph
  will be taken of the location.
• A pavement condition survey using the Utah T2
  Centers T2_RMP Pavement Management Program will
  be conducted to assess surface condition and the
  added service life the Strata system provides to
  the street.

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Traffic Evaluation

•  Annual Average Daily Traffic information will be
  acquired from Utah DOT to monitor traffic
  loadings and changes in traffic conditions.
• A report will be prepared at the end of each
  yearly evaluation, summarizing evaluation
  findings and recommendations for future
  evaluations.

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Conclusion

• 1. The problem of reflective cracking in HMA
  overlays on Portland cement pavements is a
  problem faced by many transportation agencies.
  The continual development and testing of new
  technologies will help find a solution to this
  problem.
• 2. Performance monitoring of the rehabilitation
  work on 24th Street should provide information as
  to the effectiveness of the Strata Reflective
  Crack Relief System to prevent reflective
  cracking in HMA overlays of deteriorated PCCP.

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Results of Pavement Condition Surveys One Year
After Construction.(November 14, 2003)

• Following pictures show current condition of
  control section and test sections

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Pavement Condition After One Year of
Service(Control Section)
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Pavement Condition After One Year of
Service(Test Section B to C)
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Pavement Condition After One Year of
Service(Test Section C to D)
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Pavement Condition After One Year of
Service(Test Section D to E)
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Pavement Condition After One Year of
Service(Test Section E to F)
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Pavement Condition After One Year of
Service(Test Section F to G)
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Pavement Condition After One Year of
Service(Test Section G to end)
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Findings

• Performance monitoring of the rehabilitation work
  on 24th Street after one year of service shows no
  discernible cracking or distress in either the
  control section or any of the test sections where
  the Strata Relective Crack Relief System was
  placed.
• All sections are performing well with no
  discernible rutting, as well.