Airport Pavement Management

Tom Freeman, Program Manager,

Pavement Management Texas A&M Transportation Institute

Phone: 979-845-9923

E-Mail T-Freeman@TAMU.EDU

AGE

$ 0.70

$ 3.50

$ 6.15

$14.0

40 % Time

70 % Time

90 % Time

PMS Concepts

Fog $0.40 Micro $2.00 Mill and Ove $6.00 Recon AC $24.50 PCC $55.00

Example of a RunwaySection Designation.

Inspection Procedures • Inspect Primary Pavements

– FAA Condition Survey – 20% Inspection Rate

• 2 Runways • Taxiways • Aprons

• Document Conditions and Distresses With Digital Photos

• “Plain English” Report of Conditions

• Videotape Runway Ends, Pavement, and Tours

Put all data on CD

Step 1. Inspect sample units to determine type, quantity and severity level of pavement distresses.

Low SeverityLongitudinal Cracks

Medium SeverityAlligator Cracks

Step 4. Adjust Total Deduct Value.

Step 5. Compute Pavement Condition Index, PCI=100-CDV, for each sample unit inspected.

Step 6. Determine Pavement Condition Rating

Total Deduct Value0 100 200

What Did We Find?

Center AC Pavements

15.0 20.0 25.0 30.0

Age

Basic

General

Transport

Other

ACCEN

2.75 Points/Yr

Family Curve for Center AC Pavements

ements

20.0 25.0 30.0

Basic

General

Transport

AACCEN

3.23 Points/Yr

Family Curve for Center AAC Pavements

Three Major Distresses

Three Major Distresses • Edge Cracking and Encroachment

Three Major Distresses • Edge Cracking and Encroachment • Weathering and Raveling

Three Major Distresses • Edge Cracking and Encroachment • Weathering and Raveling • Block Cracking

Edge Happens !!

• Moisture Changes Along Edge of Pavement – Less Water Under Pavement – More Water Along Edge

• Soil Shrinks and Swells

Edge Happens !!

• Moisture Changes Along Edge of Pavement – Less Water Under Pavement – More Water Along Edge

• Soil Shrinks and Swells • Differential Temperature • Fix By Crack Sealing (Kill Weeds) • May Be Able To Address In Design - Wider

Bases

Encroachment • Weeds and Grasses Along Edge of

Pavement • Causes Cracking Along Edge, FOD,

Weathering of Pavement • Reduces Width of Pavement

Encroachment • Weeds and Grasses Along Edge of

Pavement • Causes Cracking Along Edge, FOD,

Weathering of Pavement • Reduces Width of Pavement

• Fix With Mowing, Herbicide, Grading,

Millings, Wider Bases

Low Severity Block Cracking - Low Weathering

Medium Block Cracking, Medium Raveling

What Causes This?

What Causes This?

• Lack of Traffic • Sun/Ultraviolet and Oxygen Remove

Volatiles (Maltenes) • Pavement Gets Brittle • Daily and Annual Temperature Cycling

What Causes This?

• Lack of Traffic • Sun/Ultraviolet and Oxygen Remove

Volatiles (Maltenes) • Pavement Gets Brittle • Daily and Annual Temperature Cycling

• Asphalt Worn Away, Aggregate Gets Loose • Hello FOD, Goodbye Paint

Fixes

• Fix Block By Mill and Overlay, Cape Seal, or Reconstruct

Fixes

• Fix Block By Mill and Overlay or Reconstruct – Expensive – Deteriorates Slowly, So We Can Wait. – Fog to Reduce Rate – May be able to use Cape Seal

Fixes

• Fix Block By Mill and Overlay, Cape Seal, or Reconstruct – Expensive – Deteriorates Slowly, So We Can Wait. Fog to

Reduce Rate • Fix Weathering and Raveling by Fog, Coal

Tar, Rejuvenator, or Slurry all BEFORE Cracking

When Is The Proper Time To

Do Work?

Too Late?

Way Too Late!!

Wait Until Cracked and Slurry Seal

If Cracks Are Small, Will Perform Better, But To PREVENT Reflection Cracking, Must Treat BEFORE It Cracks

Cracks Come Right Back Through

Some Longitudinal and Transverse Cracking

Fix by Sealing Cracks

Lots of Sealed Longitudinal Cracks

Routine Preventive Maintenance is the Key

• Preserve, Protect, or Renew Surface to Prevent Cracking

• For Airports, Block Cracking is Death. Must Treat BEFORE All Cracked Up!!

So, Protect Pavement From Cracking and Weathering By:

• Fog Seal (Use on HMAC, Slurry, Seal Coat) – Dilute AC Emulsion

• Coal Tar Seals – Non-Asphalt Based – Some Include Sand

• Rejuvenators (HMAC Only) – Specially Formulated To Replace Volatiles

Protection (Continued)

• Microsurfacing or Slurry Seal (Use on HMAC, Slurry, Seal Coat) – Asphalt And Aggregate

• Crack Seal

Do Same Things You Have Been Doing, Just Do Them Earlier

Fog Seal, Coal Tar, or Rejuvinator

Pre-P401?

Slurry Seal

Plan of Attack

• Seal Cracks (Every Two Years@ $0.10/Ft) • Blade Edges and Kill Weeds (Annual) • Fog Seal (Every 2-4 Years @ $0.20 - $0.50/SY) • Rejuvenator (See Manufacturer) • Micro or Slurry Seal (5-7 Years @ $2/SY)

Why Preventive Maintenance?

Why Not Just Let It Rot?

0

10

20

30

40

50

60

70

80

90

100

1/31/93 6/15/94 10/28/95 3/11/97 7/24/98 12/6/99Date

PCI Good

Fair

Poor

PCI Performance Curves for Microsurfacing

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50Age

PC

I

PreventiveMaintenance

$1.50/SY $1.20/SY $1.50/SY

Total = $4.20

Runway Closed 1 - 3 Days Each Time

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50Age

PCI

Overlay

$6/SY $6/SY $6/SY

Total = $18

Runway Closed 4 - 10 Days Each Time

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50Age

PC

I

Reconstruct

$12/SY $12/SY

Total = $24

Runway Closed 4- 6 Months Each Time

What Should You be Doing?

What Should You be Doing?

• https://ftp.dot.state.tx.us/pub/txdot-info/avn/pmp-2000.pdf

FAA Requirements • Since January 1, 1995 airport sponsors that

accept AIP funds for pavement replacement or reconstruction are required to commit to a grant assurance which stipulates that an effective pavement maintenance/ management program will remain in effect throughout the useful life of the constructed pavement. Such a program will have four basic components:

Required Components

Required Components • a pavement inventory which shows the dimensions,

locations, and maintenance history of all paved surfaces – Show the location, dimensions, and pavement type of all

runways, taxiways, and aprons. – The year of construction and most recent major rehabilitation

Required Components • a pavement inventory which shows the dimensions,

locations, and maintenance history of all paved surfaces – Show the location, dimensions, and pavement type of all

runways, taxiways, and aprons. – The year of construction and most recent major rehabilitation

• a prescribed inspection schedule, which will minimally involve detailed annual assessments, and monthly drive-by observations – Detailed inspections must be conducted at least once annually. – Drive-by inspections must be conducted at least once monthly

Required Components • record keeping which documents inspection dates,

findings, locations of distress, and remedial actions scheduled and performed. The minimum information to be recorded is listed below, – Inspection Date – Location – Distress Type – Maintenance Scheduled of Performed.

Required Components • a method of data retrieval which would permit a

comprehensive presentation to the FAA if they request one.

Remember, if inspections and remedial actions are not documented, then they did not occur. Documentation is vital.

How to Perform Inspections

• Minimum of once per month – Walk or slowly drive the airport pavements, looking for

any irregularities, damage, or deficiencies. – Make written notes describing the date, the pavement

section, the location, the type, and the extent of the problems. Forms are in report.

– Note the corrective action taken, or to be taken, including the date of action.

Questions?

Airport Pavement Management

Tom Freeman, Program Manager,

Pavement Management Texas A&M Transportation Institute

Phone: 979-845-9923

E-Mail T-Freeman@TAMU.EDU