Article 105-3 of the North Carolina Department of Transportation (NCDOT) Standard Specifications for Road and Structures provides guidance on price adjustments for hot mix asphalt pavements that are not within reasonably close conformity with the specifications but for which the work is to be accepted and remain in place. The primary objective of this research is to refine these price adjustments.
The research objective will be accomplished by conducting both field and laboratory analyses of deficient pavements and specification pavements with similar structures and traffic history. The types of deficiency to be addressed in this research include asphalt content and in-situ density. Both fatigue and rutting performance will be evaluated. The field study will include the analysis of condition survey data and available Falling Weight Deflectometer (FWD) data for remaining life prediction. The remaining life prediction algorithm using FWD deflections that will be used in this report was determined by a relatedResearch Project 2000-04, ""Use of Falling Weight Deflectometer Multi-Load Data for Pavement Strength Estimation."" The laboratory study will be performed on cores obtained from eight selected pavements as well as laboratory fabricated specimens of the hot mix asphalt (HMA) mixtures for those pavements.
The laboratory test program will include: Indirect tension tests for fatigue performance evaluation; Repeated load triaxial tests for rutting evaluation; Accelerated pavement tests on laboratory pavement slabs for fatigue and rutting evaluation using the third scale Model Mobile Loading Simulator.
Both field and laboratory analysis results will be compared to develop prediction models for fatigue and rutting performance of asphalt concrete. Two levels of economic analysis will be performed to determine appropriate pay adjustment factors. The first level uses the ratio of the service lives of specification and deficient HMA mixtures determined from laboratory testing and accelerated pavement testing. The second level involves the life cycle cost analysis of specification and deficient pavements.
If necessary, recommendations will be made for revisions to the NCDOT Standard Specifications for Roads and Bridges. In addition, the system comprised of pavement performance prediction models and economic analysis that will be developed from this study will establish a framework on which a future pavement design, rehabilitation design, and performance-related specification (PRS) may be built.
