What You Need to Know about Airport Pavement ...

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Airport Pavements – Huge Investment. ▫ Important to Preserve this Investment. ▫ Effective Pavement Preservation Program. • Right Pavement. • Right Treatment.
What You Need to Know about  Airport Pavement Preservation David K. Hein, P.Eng. Applied Research Associates, Inc.

What it Looks Like New!

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What Do I Do Now?  

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Why the Interest in Pavement Preservation?

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FAA Research to Extend Airport Pavement Service Life  Airport Pavements – Huge Investment  Important to Preserve this Investment  Effective Pavement Preservation Program • • •

Right Pavement Right Treatment Right Time

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Construction of Airport Asphalt Pavement  Mix Properties Critical  Poor Compaction of Longitudinal  Joints Results in Raveling & Cracking

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Construction of Airport Rigid Pavement

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Construction of Airport Rigid Pavement

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Proof Rolling    

Required on military airfield construction, TM 5‐825.2 Used to locate isolated soft spots in compacted soil Increases compaction of base course to required density Proof Roller  • Four large rubber tires • 30,000 lbs (13,600 kg) on each tire • 150 psi (1 MPa) tire pressure  Rolling Pattern • 30 coverages • Centre 75 ft (23 m) of  Type A runways

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FAA Research to Extend Airport Pavement Service Life  Federal Aviation Administration developing new  models for pavement performance at the National  Airport Pavement Test Facility in Atlantic City

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Concept of Longer Service Life Pavement Condition Index

 Preventive Maintenance Reconstruction

 Acceptable Serviceability

 Unacceptable Serviceability Time

Pavements deteriorate with time  through development of a range of  distresses Pavement life can be extended with  proper maintenance Deterioration ultimately reaches a  level of unacceptable serviceability

Current FAA design is typically for a  20‐year pavement life Some pavements last longer than 20  years while others fail prematurely What factors impact extended  pavement service life?

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Effective Maintenance  Timely Maintenance Retards Rate of Deterioration  Rigid Pavements • • • • •

Timely Spall Repairs Effective Patching Materials Crack Sealing Joint Resealing Slab Replacements

 Flexible Pavements • • • •

Crack Seals Patches Thin Surfacings (Micro‐Surfacing, Slurry Seal, Fog Seal) Mill and Overlay

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Life‐Cycle Costing

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General Flowchart for Pavement  Preservation Pavement Surface/Type Asphalt Concrete

Exposed PCC

SurfacedTreated

Other Features GravelSurfaced

•Drainage improvements •Vegetation control •Etc.

Repeat for other pavement types and features Trigger Values and Timing of Maintenance Distress type, severity and density • Roughness • Rutting • Alligator cracking • Flushing, etc.

Management Aspects

Available Treatments • Hot and cold mix patching • Spray patching (manual chip seal) • Routing and sealing of cracks • Micro-surfacing • Etc.

Treatment Selection

Technical Aspects

• Pavement/maintenance management system

• Roadway functional type • Geographical area/environment

Treatment Implementation

• Other planning tools

• Size of municipality

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Specific Flowchart for Pavement  Preservation  Asphalt

Exposed

Concrete

PCC

 Preservation Type

Pavement Type

Composite

Treated

GravelSurfaced

 Treatments Emergency maintenance treatments • Patching using hot or cold mix • Infrared patching • Spray patching (manual chip seal)

Emergency Maintenance

Localized

Surface -

 Pavement Defects Loss of friction Loss of surface material and segregation Potholing Surface deformation and rutting, etc

Maintenance

Area Maintenance

Rehabilitation/ Reconstruction



Technology Items • • • • •

Synopsis Specifications and manuals Field performance reports Laboratory and technical reports Investigative and forensic reports

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ACRP Synthesis Project 11‐03 Scope and Objectives  Objective • Document how airports implement a pavement maintenance management  program, including inspection and tracking pavement condition, scheduling  maintenance, identifying necessary funds, and treating distresses in asphalt  and concrete pavements

 Goal • Document effective practices and differences in maintenance practices by  pavement type, airport category and geographical location (e.g., weather  and availability of materials) • Information obtained from literature review and survey of airport practices

 Target Audience • Airport pavement engineers and pavement maintenance managers and  personnel 17

Survey of Maintenance Practices  Surveys from 50 airports ranging in size, geographical location,     

aircraft operations Over 80% have functional Pavement Management System (PMS) 30% rated PMS as excellent and essential 38 separate M&R treatments identified from survey results Reduced to 24 common M&R treatments • 12 for asphalt pavement surfaces • 9 for concrete surfaces • 3 applicable to both surface types

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Development of PMS 1. Design of APMS  Needs of the users  Expected results

2. Pavement inventory & evaluation  Inventory and database  Pavement evaluation  Performance prediction

Network Level:

Selecting the right

3. Technology of pavement preservation treatments

section at the right time

4. Identification of needs  Levels of service Preventive maintenance

Other pavement preservation needs

5. Prioritization, planning and budgeting

6. Project design and implementation Project Level:

7. Operation, sustainability and enhancement

Designing and implementing the right treatment

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M&R Based on Pavement Condition Index Description

Applicable pavement preservation treatments

86-100

Good – only minor distresses

Routine maintenance only

71-85

Satisfactory – low and medium distresses

Preventive maintenance

56-70

Fair, some distresses are severe

Corrective maintenance and rehabilitation

PCI Rating

41-55 26-40 11-25 0-10

Poor – severity of some of the distresses can cause operational problems Very poor – severe distresses cause operational problems. Serious – many severe distresses cause operational restrictions Failed – pavement deterioration prevents safe aircraft operations

Rehabilitation or reconstruction Rehabilitation and reconstruction Immediate repairs and reconstruction Reconstruction

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Residual Life  Time left until asset failure  Straight line or decay curve approaches Predicted performance A

B

Asset Condition

Remaining service life

Minimum acceptable service level Past performance

Now Asset Age, years

Now +2

Now +5

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Level of Service  Level of Service (LOS) defines desired surface condition Performance curve Pavement Condition Index, PCI

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Trigger level for crack sealing Target level of service for average network condition Trigger level for overlay (mill and fill) Minimum acceptable level of service for individual sections

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Pavement age, years

 Higher LOS can result in higher M&R costs 22

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Preservation Techniques Fog Seal

Crack Seal

Micro-Surfacing

Ultrathin Bonded Wearing Course

Slurry Seal

Thin HMA Overlay

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Catalog of M&R Treatments Both Pavement Types   

Texturization using shot blasting Diamond grinding Micro-surfacing

Asphalt Concrete            

Sealing and filling of cracks (hot or cold applied sealants) Small area patching (hot mix, cold mix or proprietary material) Spray patching (manual chip seal and mechanized spray patching) Machine patching with AC material Rejuvenators and seals Texturization using fine milling Surface treatment (chip seal) Slurry seal HMA overlay (includes milling) Hot in-place recycling Cold in-place recycling Ultra-thin Whitetopping

Portland Cement Concrete         

Joint and crack sealing (with bituminous, silicone, or compression sealants) Partial depth repairs (AC, PCC, and proprietary materials) Full depth repairs (AC, PCC, and proprietary materials) Machine patching using hot mix Slab stabilization and slabjacking Load transfer Crack and joint stitching Hot mix overlays Bonded PCC overlay

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Example of Fact Sheet (Hot Mix Overlay) 1. Optional vibratory dual steel drum rollers 2. Rubber tired rollers Optional material 3. Static dual steel drum rollers transfer vehicle Paver

Hot mix truck Asphalt distributor

Milling machine

Tack coat application

Optional built -in tack coat application

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Power broom

Description of Process Resources Purpose and Selection Criteria Typical Service Life and Costs Materials and Construction Airport Experience 25

Survey‐ Use of AC Treatments Survey Result, %

Very Good

Good

84 9 52 43 9

11 7 16 18 11

95 16 68 61 20

19 17 42 13 25

71 66 58 50 50

10 17 0 37 25

5

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0

100

0

27 34 7

14 18 5

41 52 11

39 39 20

55 61 80

6 0 0

0

16

16

0

71

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Poor

Total

hot-poured sealant cold-applied sealant hot mix Small area (pothole) patching cold mix using proprietary mix Spray patching (includes manual chip seal) Machine patching with AC Milling and machine patching with AC fine milling Texturization using controlled shot blasting Crack sealing with

Performance

Have Tried

Treatment Type

Routine

Usage

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Survey‐ Use of AC Treatments (cont’d) Rejuvenators, fog seals, etc. Surface treatment Slurry seal Micro-surfacing Hot mix overlay Milling and hot mix overlay Hot in-place recycling Cold in-place recycling Whitetopping (PCC overlay)

30 15 23 2 45 45 5 2 7

23 18 25 9 23 18 2 0 7

52 43 48 11 68 64 7 2 14

23 6 10 25 48 58 N/A N/A 60

59 81 75 75 48 42 N/A N/A 20

18 13 15 0 4 0 N/A N/A 20

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End Result Pavement performance curve

Pavement Condition Rating

100

Preventive Maintenance

Change due to a preventive maintenance treatment

70 Maintenance and Rehabilitation Minimum recommended condition Benefit Reconstruction

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Extended pavement life due to preventive maintenance

5

10 Pavement Age, years

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