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Highway Quality Compendium
Pavement Warranties Yield Innovation, Quality
Faced with staff and budget shrinkages and the need to increase pavement quality and life-cycle performance, some State highway agencies are finding that pavement warranties offer an alternative way to assure performance. These warranties guarantee the integrity of the product and the contractor's responsibility to repair or replace defects for a defined period.
The Indiana Department of Transportation (INDOT) started using warranties on asphalt pavements 7 years ago. The agency's goal was to encourage contractor innovation and at the same time compensate for a decrease in manpower for inspection and oversight. "We wanted to be able to do more with fewer people," says Dave Andrewski of INDOT. Indiana awards about two or three warrantied projects a year, with the warranties good for 5 years. The warranties are placed on very high traffic volume projects in conjunction with time incentives. This is done to ensure that the fast pace of construction that time incentives encourage still produces a high quality project for INDOT. The effort started with asphalt pavements but expanded last year to concrete with the construction of a warrantied pavement on I-65 in the southern part of the State. The warranty specifications were developed in concert with industry. Indiana is pleased with the results to date. "The projects are built faster and we get quality work and very smooth pavements," says Andrewski.
At the end of the 5-year warranty period, threshold values for International Roughness Index, surface deformation (rutting for asphalt pavements/scaling for concrete pavements), transverse cracking, longitudinal cracking, friction number, and joint sealant condition (for concrete pavement only) are measured. If the pavement meets those values at the 5-year mark, then INDOT is confident based on historical data that the pavement will be serviceable through its design life. To date, two asphalt pavement contracts have reached the 5-year mark and both have been accepted.
The Michigan Department of Transportation (DOT) started using warranties in 1996. While the agency started with materials and workmanship warranties, it has since expanded the warranty program to include performance warranties also. Performance warranties allow the contractor more flexibility in terms of materials selection, workmanship methods, and design decisions. "We started exploring warranties as a way to reduce oversight but still ensure that contractors are delivering the high quality product we need. It's also about getting contractors to take a long-term interest in pavement performance," says Steve Bower of Michigan DOT. "We're trying to get the contractors to have a high level of self awareness with regard to construction quality. It raises awareness about how workmanship and materials decisions can affect long-term pavement performance." From 1996-2002, the State let 473 preventive maintenance projects that had warranties and 131 rehabilitation projects. More than 90 percent of projects in the agency's 2002 Capital Preventive Maintenance (CPM) Program were warrantied, while more than 50 percent of 2002 reconstruction and rehabilitation projects included a pavement warranty.
CPM pavement warranties are for a 3-year duration and include treatments such as thin asphalt overlays, concrete patching, chip seals, and microsurfacing. Rehabilitation and reconstruction warranties are for a 5-year duration and include fixes such as new concrete and asphalt construction, hot-mix asphalt (HMA) overlays on repaired pavement, and HMA overlays on rubblized concrete pavement.
In December 2002, the DOT began work on a 19.3-km (12-mi) project on the M-6 Freeway Bypass in Grand Rapids that will have a 7-year performance warranty. "The contractor will have additional flexibility with the mix design, more than would usually be given under the standard QC/QA approach," says Bower. Two more performance warranty projects will be let in March 2003, using the same specifications.
Michigan reports that its construction oversight costs have dropped since it started using warranties. The DOT has not yet seen a longer service life for pavements but it has observed more innovation on the part of contractors. Lessons learned have included the need to have a good pavement management system (PMS) in place. A good PMS is necessary in order to have the comprehensive pavement performance data that is needed for developing pavement performance measures and thresholds. Bower notes that the agency picked thresholds and performance levels that are attainable based on pavement management data from past projects. "It is imperative that you manage the risk for contractors or it will translate into higher bid prices," says Bower.
For more information on Indiana's warranty use, contact Dave Andrewski at INDOT, 317-610-7251, x. 212 (email: firstname.lastname@example.org). For more information on Michigan's warranty program, contact Steve Bower at Michigan DOT, 517-322- 5198 (email: email@example.com). To learn more about pavement warranties in general, contact John D'Angelo at FHWA, 202-366-0121 (fax: 202-493- 2070; email: firstname.lastname@example.org).
Reprinted from Focus, January/February 2003.
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