Impacts of Climatic Regions and Design Factors on the Condition and Distress of Specific Pavement Test Sections in the Long-Term Pavement Performance Program

Abstract

One of the objectives of the Long-Term Pavement Performance Specific Pavement Studies (SPS)-1 experiment was to examine the effects of climatic regions and various design factors on the performance of flexible pavements. In a research study sponsored by FHWA’s Long-Term Pavement Performance program, the impacts of climatic regions, drainage, and the thickness of asphalt concrete layers on the functional and structural performance of the flexible pavement test sections of the SPS-1 experiment were analyzed. Functional performance was analyzed on the basis of ride quality [determined by using the international roughness index (IRI) and safety (rut depth)]. Structural performance was analyzed on the basis of alligator, transverse, and longitudinal cracking and rut depth. For each SPS-1 test section, functional performance was represented by the remaining functional period (RFP), and structural performance was represented by the remaining structural period (RSP). Both metrics, the RFP and the RSP, were developed in this study to rate the performance of flexible, rigid, and composite pavement sections. This paper presents and discusses the results of the analyses of the performance of the SPS-1 test sections. It is shown that, as expected, pavement performance is a function of the climatic region. Wet–freeze regions had a significant impact on pavement performance in terms of the IRI, rut depth, and cracking, and drainable bases were found to be more effective in the wet–freeze region than in the wet–no-freeze, dry–freeze, and dry–no-freeze regions.