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 application of elastic theory to the design of overlays on existing pavement requires that a modulus of elasticity be assigned to the existing structural system. Estimates of elastic modulus are obtained from dynamic deflection reading in the field; but asphalt is a highly temperature-sensitive visco-elastic material and deflections not corrected to a standard temperature can produce misleading results. It is therefore the objective of the present study to develop a procedure for estimating an effective modulus of elasticity for a layer of asphaltic concrete in which some temperature gradient exists because of the combined influences of solar radiation, wind, air temperature, cloud cover and other variables specific to time and location which cause temperature variation within the pavement layer. Two models are presented from the achievement of that objective.