This synthesis will be of interest to administrators, including contract and specifications administrators; research, construction, materials, specification, and design engineers; agency project managers and staff; and highway construction contractors. It describes the state of the practice with respect to the development and present status of performance-related specifications (PRS) for highway materials and construction. This report of the Transportation Research Board summarizes the historical events that have prompted U.S. interest in PRS development and describes the underlying concepts. In addition, it describes current practice with regard to PRS implementation and refers to the principal PRS literature with emphasis on performance and cost models. It emphasizes the utility of PRS in providing objective/ rational measures that can be used for special contract conditions, such as incentive or disincentive adjustments.

This research focused on the development of fatigue-based payment adjustment factors for use in performance-related specifications for full-depth asphalt pavements. A rational method of adjusting a contractor's payment as a function of the quality of the product is an essential element of a performance related specification (PRS). The Quality Control/Quality Assurance (QC/QA) specifications and practices in the highway industry for the construction of asphalt pavements were reviewed. The survey indicated that many hybrids of method related and end result specifications are being used by the states. Currently, no state is known to be utilizing a PRS for full-depth pavements. Details of the QC/QA program, testing and sampling frequencies, and payment adjustment schedules are presented. A review of extant performance prediction models indicated that additional research in developing quantifiable relationships between the key distresses in an AC pavement and contractor controlled material and construction (M&C) variables is necessary before a comprehensive PRS can be developed. However, satisfactory secondary relationships between the M&C variables (air voids, asphalt content, fines content and thickness) and fatigue cracking, a major structural distress, were identified. Fatigue failure is thought to be influenced not only by the mean values of the M&C factors but also by their variability. A computer simulation program was developed to examine the effect of deviations from target quality levels. The economic consequence of these deviations was examined by using a life-cycle costs strategy that included maintenance and user operating costs. A rational payment adjustment schedule was defined as one that would provide a mechanism by which pay adjustments could be established that would reflect the economic impact of contractor nonconformance to target quality levels. The pay factors developed are a function of the percent change in the anticipated present worth of the life-cycle costs of the as-constructed pavement compared to the as-designed pavement.

The research conducted as part of this thesis was intended to analyze the adequacy of the current quality control (QC) method used by the Texas Department of Transportation (TxDOT) to control hot-mix asphalt (HMA) projects. Based on this analysis, the author recommended the development of a pay-adjustment factor (PAF) system based on actual pavement performance. In this way, the DOT could have a more cost-effective method to penalize or reward the contractors, since the PAF practice will be based on field performance rather than historical trends. The secondary goal was to compare the pavement construction QC data variability between DOT engineers and contractors. This effort was used to validate whether TxDOT could cost-effectively use contractors test results for quality assurance (QA) purposes. This thesis only focuses on the Type C and Type D dense-graded hot-asphalt mixtures used in Texas, and the pavement performance data were constrained to the past five years.