Impacts of Maintenance Treatments on the Life Cycle Pavement Condition and Distress of the LTPP SPS-3 Test Sections

One of the objectives of the Long-Term Pavement Performance (LTPP) Specific Pavement Studies (SPS)-3 experiment is to examine the effectiveness of maintenance treatments on the performance of flexible pavements compared to the performance of untreated control sections. The applied maintenance treatments include slurry seal, chip seal, crack seal, and thin overlay. In a research study sponsored by the LTPP program of the Federal Highway Administration (FHWA), the impacts of these maintenance treatments on the functional and structural performance of the flexible pavement test sections of the SPS-3 experiment were analyzed. The analyses of the functional performance was based on ride quality using the International Roughness Index (IRI) and safety (rut depth), while analyses of the structural performance was based on the pavement alligator, transverse, and longitudinal cracking and on rut depths. For each SPS-3 test section, the functional performance is represented by the Remaining Functional Period (RFP) and the structural performance 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-3 test sections. It is shown that, as expected, after treatment pavement performance is a function of the before treatment condition or distress. The thin overlay treatment was most effective and improved the pavement performance relative to IRI and rut depth but did not improve the pavement performance relative to alligator, longitudinal, and transverse cracking.