Evaluation of Short-Term Warranty and Prescriptive Specifications for Hot-Mix Pavements after 8 Years

Abstract

Asphalt concrete pavements constructed according to conventional construction specifications were compared with projects constructed according to performance warranty specifications. Ten projects of each type were compared to assess relative costs and benefits after 8 years. Pairs of projects were selected with similar characteristics regarding preoverlay repair work, functional class, design life, and other features to minimize bias. More than 214 lane miles of performance warranty projects were compared with 277 lane miles of prescriptive specification (control) projects. The average initial construction cost of the warranty projects was $5,318 per lane mile greater than that of 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 warranty project cost, warranty projects would have $492 higher per lane mile cost than comparable conventional projects. Although the conventional projects were constructed with a lower international roughness index (IRI) initially, after 8 years of service the warranty projects have become smoother with an IRI of 75.1 and 68.8 in. per mile, respectively. Corrective repairs were required on 2 of the 10 warranty projects during the warranty period. After 8 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.