Longitudinal Joint Density Test Results December 12, 2012 Garth D. Bridenbaugh, P.E. Pennsylvania Department of Transportation BOPD, Innovation & Support Services Quality Assurance Section

Longitudinal Joint Data Summary How Far Have We Come? Longitudinal Joint Data Summary Year Density Lots Avg. Joint Density Avg. Roadway Density 2007 18 87.8% 93.9% 2008 43 88.9% 94.1% 2009 29 89.2% 2010 No data, transition to PWL spec. 2011 137 91.1% 2012 158 91.5% 94.0%

Impact on Lot Payment Summary -$12,000 +$5,000 Disincentive No Pay Adjustment Incentive 50 80 100 PWT

2012 Statewide Pay Impacts 158 density lots on 51 projects (773 cores) 75% bonus lots 18% no pay adjustment 7% penalty lots $468,300 total bonus $62,976 total penalty

Corrective Action Lots with avg. density < 88% Gmm require corrective action Contractor must seal the joint with PG 64-22 at no cost to Department 4 lots of 158 required corrective action in 2012

US 322

US 422

Interstate 79

Warm Mix vs Hot Mix

Notched Wedge vs Vertical

By Highway Classification

Crowned vs Uncrowned Roadways

Mix Size and Type

2011-12 Bonus/Penalty by Individual Contractor Total bonus = $729,925 Total penalty = $162,192

More 2011-12 Joint Density Info. 686 linear miles of joint tested 1450 joint core samples 93 total projects statewide 30 different paving contractors Notched Wedge Joint Core Hole

Where is PennDOT Heading? Raising the lower specification limit from 89% to 90% for joint density Lots ≥92.0% avg. density, full bonus Lots ≥89.0% but <90.0% avg. density, penalty cap of $1,000 per sublot

2012 Test Results 2012 results under proposed changes: 52% bonus (was 75%) 30% no adjust. (18%) 18% penalty (7%) Bonuses still more than double penalty $

Why Joint Density? Lower permeability reduces chance for moisture damage Higher density reduces the permeability of the pavement in place.

Keeping water out of our joints Most research suggests that… densities should be about 92% to minimize permeability Joint densities below 90% begin to see an exponential increase in permeability as density decreases

Various Studies on Permeability Chart excerpted from NCHRP Project 9-27 September 2004

Joint Density Spec. Impacts Overall 3.7% increase in joint density (87.8% to 91.5%) since outset in 2007 Improved joint density is expected to lead to better long term performance Doesn’t solve all problems Anticipated lower maintenance costs Congratulations on a job well done, let’s take the final step forward!