Pavement Distress and Maintenance

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Pavement Distress and Maintenance

• Fall Forum 2006
• Tracy Schmidt, Mn/DOT
• Ann Johnson, PE Services

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Questions for you

• Who are you?
• Why are you here?
• What do you want to get out of today?

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Types of Maintenance

• Preventive maintenance
• Corrective maintenance
• Emergency maintenance

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Preventive Maintenance

• A program of activities
• Preserving the investment in pavements
• Extending pavement life
• Enhancing pavement performance
• Reducing user delays
• Includes corrective and preventive maintenance
  and minor rehab
• Often used to repair environmental damage
• Narrows the focus to the application of one or
  more treatments
• Applied to the surface of a structurally sound
  pavement

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Preventive Maintenance

• Preventive Maintenance is the right treatment on
  the right pavement at the right time
• How to know when to act?
• Pavement management
• Condition surveys
• Pavement condition index (PCI)
• Non-destructive testing
• FWD
• Road rater

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Todays Topics

• Flexible Pavement Distresses and Maintenance
• Rigid Pavement Distresses and Maintenance
• Turf Issues
• Pavement Evaluation

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Pavement DistressesFlexible Pavement
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Various Rating Manuals

• Pavement Rehabilitation
• A Guide for Minnesota Cities and Counties
• MN LRRB
• Distress Identification for the Long Term
  Pavement Performance Program
• SHRP
• PASER Guide in Fall Forum notebook

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Identifying the Distress is the 1st Step in the
Process
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Identifying Distresses Includes

• Name
• Severity
• Amount
• Rate what you see and not what you think.

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Flexible Pavement Distresses

• Three causes
• Environmental
• Construction/design deficiencies
• Load-related

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Cracking

• Types
• Fatigue
• Thermal/Transverse
• Block
• Edge
• Longitudinal
• Reflection
• Slippage

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Fatigue Cracking

• Causes
• Insufficient strength
• End of pavement life
• Too heavy of loads
• Cures
• Remove and replace
• Mill and overlay

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Thermal Cracking (Transverse)

• Causes
• Contraction and Expansion of Pavement with
  Changing Temperatures
• Cures
• Crack Filling
• Full-Depth Reclamation
• Full Depth Repair
• Thick Overlay

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Block Cracking

• Causes
• High Void Content
• Oxidative Hardening of the AC
• Thermal Cracking
• Cures
• Crack Filling/Sealing
• Seal Coat
• Full-Depth Reclamation
• Thick Overlay

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Edge Cracking

• Causes
• Soil Movement Beneath Pavement
• Cures
• Crack Filling/Sealing
• Full-Depth Reclamation

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Longitudinal Cracks

• Causes
• Low Temperatures
• Cures
• Crack Sealing
• Thick Overlay

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Reflective Cracking

• Causes
• Existing cracks or joints in the underlying
  structure
• Concrete slab movements
• Cures
• Crack Filling
• Extensive Pre-Overlay Repair
• Rubblizing
• Crack Seat
• Saw Seal
• Interlayer

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Slippage Cracking

• Description
• U-shaped cracks in areas of braking, turning,
  accelerating
• Causes
• Poor bond between asphalt surface and underlying
  layer
• Cures
• Crack Filling/Sealing
• Full-Depth Reclamation

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Surface Defects

• Rutting
• Shoving
• Bleeding
• Polished Aggregate
• Raveling
• Potholes
• Patching

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Rutting

• Causes
• Low Air Voids
• Asphalt content too high
• Smooth, Rounded Aggregate
• Excessive amounts of natural sand
• Excess Dust
• Cures
• Remove/Replace 100 mm (4 inches)
• Micro-surfacing

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Shoving

• Causes
• Unstable Mix
• Braking, stopping or accelerating traffic
• Slippage between layers
• Cures
• Remove and Replace
• Mill and Overlay
• Thick Overlay

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Bleeding

• Causes
• Too high asphalt content
• too rich a plant mix
• improperly constructed seal coat
• too heavy prime or tack coat
• Cures
• Sand blot
• Micro-surfacing
• Seal coat

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Polished Aggregate

• Causes
• Soft aggregate
• Heavy traffic
• Cures
• Seal coat
• Micro-surfacing
• Thin Overlay

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Raveling

• Causes
• Asphalt binder unable to hold aggregate in place
• dusty aggregates
• segregation
• low in-place density
• aged asphalt binder
• Stripping
• Cures
• Seal Coat
• Micro-surfacing
• Thin Overlay

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Potholes

• Causes
• Raveling of cracks
• Moisture damage
• Freeze-thaw
• Insufficient strength
• Cures
• Patch

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Patch Deterioration

• Causes
• Poor bonding to existing pavement
• Improper compaction
• Poor materials
• Propagation of original distress
• Cures
• Remove and replace
• Re-patch
• Assess original distress

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Miscellaneous Distresses

• Lane-to-shoulder Drop off
• Water Bleeding and Pumping

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Lane to Shoulder Drop off

• Cause
• Differences in materials used for lane and
  shoulder
• Differential settlement
• Insufficient compaction of base
• Cures
• Wedge/leveling overlay
• Micro-surfacing

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Water Bleeding and Pumping

• Causes
• Cracks
• Inadequate drainage
• Cures
• Full-depth patch
• Crack seal

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Fatigue Cracking
Mini Quiz ???

• Causes
• Insufficient strength
• End of pavement life
• Too heavy of loads
• Cures
• Remove and replace
• Mill and overlay

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Thermal Cracking (Transverse)

• Causes
• Contraction and Expansion of Pavement with
  Changing Temperatures
• Cures
• Crack Filling
• Full-Depth Reclamation
• Thick Overlay

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Rutting

• Causes
• Low Air Voids
• Asphalt content too high
• Smooth, Rounded Aggregate
• Excessive amounts of natural sand
• Excess Dust
• Cures
• Remove/Replace 100 mm (4 inches)
• Micro-surfacing

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Bleeding

• Causes
• Too high asphalt content
• too rich a plant mix
• improperly constructed seal coat
• to heavy prime or tack coat
• Cures
• Sand blot
• Micro-surfacing
• Seal coat

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Crack Sealing Video

• One of many produced by the Minnesota Local Road
  Research Board

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Crack Sealing

• Saw and Seal
• Rout and Seal
• Clean and Seal (Blow and go)
• Current Specifications
• PM, Performance results
• Recommended Applications

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Current Specifications

• Technical Memo 02-19-MRR-05
• 3719 - Crumb Rubber
• 3723 - Hot-Poured Elastic Type
• 3725 - Extra Low Modulus
• http//www.dot.state.mn.us/tecsup/

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Sealants

• 3725 is recommended for
• saw seal, and rout seal(transverse cracks)
• 3719 or 3723 for clean and seal
• Recommended application temperature - any
  temperature between the recommended safe heating
  temperature and the recommended pouring
  temperature.

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2331 Bituminous Pavement Crack Treatment

• Rout and Seal at Transverse Cracks.
• ¾ x ¾ rout.
• 3725 sealant.
• Clean and Seal at wide transverse cracks and all
  longitudinal cracks.
• 3719 or 3723 sealant.

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Edge Joint Sealing
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Saw and Seal
1/4
1/8
1/2
T/3 or 2.5in. min
5/8
1/8

• 3725 now recommended
• 3720

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Rout and Seal

• 3/4 by 3/4
• 3725 now recommended
• 3720

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Wide overband
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Underfilling
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Clean and Seal

• 3719 crumb rubber
• 3723 rubberized asphalt
• 3725 extra low modulus

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Quality Control

• Attention to details
• Temperature of sealant
• Router Bits
• Heat lances
• Dry Pavement
• Workmanship!

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Full-depth crack repair
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Spray injection patching or patching w/slurry
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Micro Surfacing
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Micro-surfacing

• Treatment life of 7-9 years.
• Surface treatment 3/8 to 1/2 thick.
• Cures in one hour - chemical break.
• Can be recycled.
• Environmentally friendly.
• Minimal traffic disruption.
• Cold process saves money.

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Micro-surfacing will -

• Fill ruts
• Restore skid resistance
• Seal minor cracks
• Correct raveling or flushed surfaces
• Reduce aging and oxidation
• Reestablish cross section
• Provide wear course

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Performance

• Wheel rut resistance - 4 to 7 years
• Skid resistance - Excellent
• Raveling resistance - Good
• Treatment for flushing - Good
• Resistance to reflection cracks - Low

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Condition of existing pavement
Project Selection

• Structurally sound
• No excessive deformation
• Moderate and high volume roads

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Construction considerations

• Repair / seal joints and cracks
• Allow sealant to cure before placement.
• Clean the surface of the road
• Tack coat
• dry or raveled surface
• concrete

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Weather conditions

• Air temperature at least 50F
• Pavement temperature at least 50F
• No rain, damp is OK
• No freezing within 24 hours

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Paving

• Continuous operation.
• Mixing time, loading the spreader -
• 15 seconds
• Spreader box and strike off during breaking time
  of 60 to 120 seconds.
• Rapid set.
• Open to traffic in one hour, cross traffic in 20
  min.

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Asphalt patching and overlays
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Rigid Pavement Distresses

• Three causes
• Environmental
• Construction/design deficiencies
• Load-related
• Most rigid pavement distresses at airfields are
  caused by construction problems

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Rigid Pavement Distresses

• Environmental
• Buckling/Shattering
• Faulting

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Buckling/Shattering

• Identification
• Usually occur in hot weather, at a transverse
  crack not wide enough to permit slab expansion
• Repair
• Partial or full-depth patch, depending on
  severity
• Cause
• Inadequate jointing and joint deterioration
• Preventive measures, such as maintaining good
  joint sealers and placement of expansion joints,
  will control blow-ups.

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Faulting

• Identification
• Vertical movement of abutting slabs at joints or
  cracks
• Repair
• Low severity do nothing
• Med and high severity grinding, slab jacking,
  or replacement

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Rigid Pavement Distresses

• Construction/design deficiencies
• Durability (D) cracking
• Joint seal damage
• Lane/Shoulder drop off
• Polished aggregate
• Popouts
• Scaling/Map cracking
• Shrinkage cracks
• Spalling (joint and corner)

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Spalling

• Identification
• Breaking or chipping of the slab at corner or
  joint
• Disintegration of the slab edges
• Do not extend vertically through slab
• Repair
• Partial or full depth patching, depending on
  severity

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Durability Cracking

• Identification
• Pattern of cracks running parallel and close to a
  joint or linear crack. A series of fine,
  hairline cracks usually cracking across the slab
  corners. This type of crack can eventually lead
  to disintegration of the entire slab.

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Durability Cracking

• Repair
• Low severity do nothing, joint sealing
• Med severity partial or full depth patching
• High severity full depth patching or total slab
  replacement

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Joint Seal Damage

• Identification
• Any condition which enables incompressible
  materials to accumulate in the joints allows
  water infiltration
• Repair
• Low severity do nothing
• Med and high severity join sealing

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Polished Aggregate

• Identification
• Aggregate in the surface becomes smooth to the
  touch. Low skid resistance.
• Repair
• Overlay, grooving or grinding

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Popouts

• Identification
• A small piece of pavement that breaks loose from
  the surface.
• Repair
• Generally occur early in the pavement life, and
  do not result in severe distress.

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Scaling/Map Cracking

• Identification
• A network of fine, shallow or hairline cracks
  which extend only through the upper surface of
  the concrete. Map cracking may lead to surface
  scaling, which is the progressive disintegration
  and loss of the wearing surface.

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Scaling/Map Cracking

• Repair
• Low severity do nothing
• Med severity partial depth patching
• High severity partial or full depth patching,
  bonded overlay

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Shrinkage Cracks

• Identification
• Hairline cracks usually a few feet long and not
  extending across slab
• Repair
• Generally occur early in a pavements life, and
  do not lead to severe distress

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Rigid Pavement Distresses

• Load-related
• Divided slab
• Linear cracking
• Pumping
• Punchout

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Turf Issues

• Corrugations
• Pest problems
• Rolling and Grading
• Turf Maintenance

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Pavement Evaluation Management
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FAA Requirements

• FAA wants assurance that investment is protected
  and maintained
• Terms and Conditions of Accepting Airport
  Improvement Grants
• With respect to a project approved after January
  1, 1995, for the replacement or reconstruction of
  pavement at the airport, it assures or certifies
  that it has implemented an effective airport
  pavement maintenance-management program and it
  assures that it will use such program for the
  useful life of any pavement constructed,
  reconstructed or repaired with Federal financial
  assistance at the airport. It will provide such
  reports on pavement condition and pavement
  management programs as the Secretary determines
  may be useful.
• Special Conditions in Federal Grants

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FAA Requirements

• Pavement Inventory
• Inspection Schedule
• Record Keeping/Retrieval
• Maintenance Plan

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Non-NPIAS Airports

• MnDOT Grants require airport be maintained in a
  safe, serviceable manner

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References

• FAA Advisory Circular AC 150/5380-6A
• Guidelines and Procedures for Maintenance of
  Airport Pavements
• FAA Advisory Circular AC 150/5380-7 or 7A (Draft)
• Pavement Management System
• FAA Advisory Circular AC 150/5320-17
• Airfield Pavement Surface Evaluation and Rating
  Manuals

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Mn/DOTs Role

• Perform PCI Surveys at public airports with paved
  runways every 3 years
• Benefits both MnDOT Sponsor
• Consistent ratings and record keeping
• Track performance and condition of the Statewide
  airport system
• Fulfills part of the Sponsors Obligation
• The information can help in developing the CIP
  and scheduling projects

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PCI Inspection Process

• Use MicroPaver system and software
• Prescribed number of sample areas base on total
  area identify them on a simple map
• Measure amount and severity of all distresses
  within each sample unit
• Enter distresses into the database, analyze and
  generate reports
• Annually update database and airport maps to
  include new construction

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PCI Reports
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PCI Reports

• Color-coded condition map

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PCI Reports

• Condition Summary Section Report

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PCI Report

• Condition Projection

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PCI Report

• Distress Report

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PCI Reports

• Future improvements
• Include construction history
• Improved deterioration curves
• Possibly some recommendations for repairs, timing
  and costs
• Information on the Aeronautics website

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On-Site Evaluation
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Field evaluation

• Break into three teams
• Evaluate pavement in groups and compare results