Sarah McDougall

Pavement Management Engineer

M&R Workshop – Feb 19th 2014

Pavement Management

o State of Delaware Maintains 89% of the mileage in the stateo 4,400 centerline miles of State Maintenanceo 1,500 centerline miles of Suburban Streets

o The Pavement Management Team (PMT) is responsible for the maintenance and rehabilitation of State Maintenance Mileage

Delaware’s Roads

Pavement Management Performance Measures

• Overall Pavement Condition (OPC)

Good – OPC>60

Fair – OPC between 50 and 60

Poor – OPC<50

• Goal: 85% of roads in good or fair condition with no more than 10% rating fair

• 2013 Ratings: 99% of state maintenance roads have an OPC of 50 or greater

Pavement Management Basics

Pavement Deterioration Curve

o Avoid a “worst first” mentalityo Fewer miles would

get done spending large amounts of money reconstructing poor pavements

o More miles can be rehabbed for the same budget with roads that are in fair condition

o We need a mix of preservation, rehabilitation, and reconstruction to keep the overall road network in good condition

A pavement needing reconstruction is not going to get much worse…a pavement in fair condition though, can quickly deteriorate into poor

o DelDOT’s Pavement and Rehabilitation program strives to maintain the condition of its roadways by systematically identifying candidates for rehabilitation and determining the most cost effective treatment

How do we do this?

Road rating

Candidate List

Prioritization Score

OPC score

PMT Scoring

Scoping List

Scoping Trips

Location Remedies

List for Bond Bill Approval

o Semi automated condition survey collected every other year by consultant contracto Semi automated: combination of visual condition evaluation along

with computer measurements of roadway distresses o Video Van collection of images and measurements which are

reviewed and analyzed in office

Road Rating

o Analysis to determine OPC completed by same consultant agreement that collects data

o Roads are divided into rating segments

o Each pavement type has a set of distresses that are looked for and evaluated by severity and extent

o Pavement types: Flexible, Rigid, Composite, Surface Treatmento Severity and Extent each rated as Low, Medium, or High

o Using a set of distress indices based severity and extent rating, OPC is calculated using the following formula:

OPC = Mean of index values -1.25 x Standard deviation

o OPC is on a scale of 0-100, 100 being “perfect pavement”

Determining OPC

Flexible Pavement Distresses:

Fatigue Cracking

Transverse Cracking

Block Cracking

Patch Deterioration

Surface Defects

SEVERITYDEFICIENCY LOW MEDIUM HIGH

Fatigue Cracking

Fine parallel hairline cracks

Alligator crack pattern clearly

developed

Alligator crack pattern clearly developed with spalling and/or

distortion

Example

EXTENT

DEFICIENCY LOW MEDIUM HIGH

Fatigue Cracking

0 - 9% (wheel path)

10 - 25% > 25%

Fatigue Cracking Index

If distress is not presentIndex=100

Extent

Low Medium High

Severity

Low 92 84 70

Medium 80 58 40

High 72 46 20

Example

A index value is determined for every distress in the rating segments surface type classification and put into the OPC equation.

This is done for every state maintained rating segment in the state (in 2013 there was a total of 25,092 rating segments)

o Pulled based on OPC thresholds by functional class

o The list is reviewed to remove anything that is already approved as part of the paving list from a previous year

Candidate List

Functional Class OPC Threshold

Interstates, Arterials <70

Collectors <60

Locals <50

o PMT field reviews all roads on the candidate list

o Roads are given of score of 1-3 in the following categories:o Pavement Condition • Ride quality, distresses causing safety issues, etc.

o ADT • Set scale for each functional classification

o Functional Classification • Set scale for each function classification

o Special Conditions/Transportation Needs • Types of facilities on road (farms, employment centers, schools,

firehouse etc)

o Pavement Management Team Modifier • Previous nominations, project linkage, safety concerns

Prioritization Scoring

Prioritization Scoring

o Each scoping location is looked at by various groups within DelDOT to choose the most suitable rehabilitation treatmento Materials and Research, Construction, Maintenance

o Preliminary Cost Estimates are done, and the list is refined based on what the annual budget is assumed to be

o Final list of Pave and Rehab candidates is sent over for approval in the annual Delaware Bond Billo Also sent over for approval are lists complied for pavement

preservation treatments such as microsurfacing, tar and chip, and thin overlayo Locations are nominated by maintenance districtso locations noted by PMT throughout the year

o Once approval is given, refined estimates are started and packaged into contracts for construction

Scoping Trips and Beyond

Questions?