Asphalt concrete pavements constructed using conventional construction specifications were compared with projects constructed using short-term warranty specifications. Ten of each type of project were compared to assess relative costs and benefits after eight years. Pairs were selected with similar characteristics regarding pre-overlay repair work, functional class, design life, and other features, to minimize bias. Over 214 lane-miles of warranty projects were compared to 277 lane-miles of control projects. Average initial construction costs of the warranty projects were $5,318 per lane-mile greater than the control projects. However, the warranty projects included an annual review process and weigh-in-motion (WIM) facilities. The cost of these items added $2,573 per lane-mile. However, the conventional projects were constructed with smoothness specifications resulting in lower average roughness and incentive payments of $2,253 per lane-mile to the contractor. Therefore, if the annual review process and WIM facilities were removed from the warranty project cost in the future the warranty projects would be $492 per lane-mile higher in cost than comparable conventional projects. Although the conventional projects were constructed with a lower IRI (international roughness index) initially, after eight years service the warranty projects have become smoother with IRI of 75.1 and 68.8 inches per mile, respectively. Corrective repairs were required on two of the ten warranty projects during the warranty period. After eight years, the average cost of maintenance for the warranty projects was $26,189 per lane-mile, while the average for the control projects was $13,921 per lane-mile.
Samenvatting