Trenton M. Clark, P.E. Director of Engineering Virginia Asphalt Association

Economics is defined as – The study of the production and consumption of goods and the transfer of wealth to produce and obtain those goods.

How do Pavements tie in? They are the “goods”.

Taxes and other user fees are “the transfer of wealth”.

The Four Phases of a Pavement’s Life: Initial Construction

Functional Improvements

Structural Improvements

End of Service Life (Pavement Death)

Fact - Most pavements never really “die”!

They are seldom removed from service at the end of their service life.

Many are kept on “life-support” with short-term fixes.

Some become part of the foundation for “new” pavements.

A few are reconstructed through major rehabilitation and/or reconstruction (sometimes in-place).

VDOT has Numerous Challenges 4,500 lane miles of asphalt surfaced interstate pavements.

Over 22,000 lane miles of asphalt surfaced primary pavements.

Approximately 50,000 lane miles of asphalt surface secondary roads.

A set goal of keeping 82% of all its pavements in acceptable condition.

Very limited funding.

13%

10%

13%

20%

44%

2012 Interstate Condition Data - AC Surfaces Only

<60

60 - 69

70 - 79

80-89

90-100

19%

9%

15%

21%

36%

2012 Primary Condition Data - AC Surfaces Only

<60

60-69

70-79

80-89

90-100

y = -2.7653x + 100 R² = 0.9716

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Wt.

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rage

CC

I

Pavement Surface Age

CCI Weighted Average vs. Age (2002-present)

y = -2.5863x + 100 R² = 0.9168

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Pavement Surface Age

Weighted Average CCI vs. Age (2000 - present)

y = -5.2372x + 100 R² = 0.9281

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CI

Pavement Surface Age

Interstate System - Surface Treatment Wt. Average CCI vs. Age

y = -6.5982x + 100 R² = 0.9047

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Pavement Surface Age

Primary System - Surface Treatment Wt. Average CCI vs. Age

Interstate AC mixes placed since 2000 have an average life to a CCI = 60 of 15.5 years.

Primary route AC mixes placed since 2002 have an average life to a CCI = 60 of 15 years.

Interstate latex/slurry seal have an average life to a CCI = 60 of 7.6 years.

Primary route latex/slurry seal have an average life to a CCI = 60 of 6 years.

What is the desired resurfacing cycle for each system – 12 years, 15 years, 20 years?

How should pavement preservation practices (slurry seals/latex and thin AC overlays) be incorporated to maximize service life?

What is the best way to address structurally deficient pavements – deep mill and replace, pavement recycling, reconstruction?

15 Year Resurfacing Cycle for all Systems

1.5” functional improvement overlay

5,100 lane miles of overlay per year

3.2 million tons of AC surface mix required

At current price approximately $270 million required AC surface mixes only

$18.7 million additional funds needed to mill all Interstates and Primary routes before paving.

Funding set to meet 15 year cycle results in 6.7% deficient pavements on interstate and primary routes.

Virginia interstate and primary pavement deficiencies are currently 13% and 19% respectively.

Mix deterioration rate matches funding cycle when proper mixes are used.

Preventive maintenance treatments can be used to extend life when used properly. Proper use is a function of surface condition and timing. Too early in the service life of an AC surface is a waste of funds with no improvement. Too late results in a Band-Aid with little extension of service life. Pavement marking should be selected based entire service life of materials, not just early years.

Numerous activities make up annual cost to maintain VDOT’s pavement network.

These activities can be divided into two broad categories

Planned maintenance

Unplanned maintenance (i.e., emergency repairs)

The following is an analysis of VDOT’s pavement network expenditures since 2001

$-

$1,000.00

$2,000.00

$3,000.00

$4,000.00

$5,000.00

$6,000.00

$7,000.00

$8,000.00

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Average Annual Cost to Maintain AC Surfaced Roads in Virginia

Total Cost/Lane Mile (AC Only) Total Cost/Lane Mile (All Hard Surfaced)

$-

$5,000.00

$10,000.00

$15,000.00

$20,000.00

$25,000.00

$30,000.00

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Cost Per Lane Mile – PCC vs. AC Surfaces

PCC Roads AC Roads

All aged and cracked surfaces should be milled. Thicker is not better, sound structure is better. Brittle older surface layers overlaid have tendency to rut.

Use rut resistant intermediate mixes (IM-19.0E or SMA-19.0 (76-22)) for deep milling. Stronger binders and mixes should be used at intersections with heavy truck use. Timing is everything in order for preventive maintenance treatments to extend pavement resurfacing cycle. Move forward with recommendations of Asphalt Quality Task Force.

Annual Pavement Maintenance Funding should be a function of Lane Mileage to maintain a 15 year resurfacing cycle.

Annual funding amount should/will fluctuate as costs change.

Lane based funding will stabilize pavement conditions.

Improved paving materials and practices should result in longer service lives.