Estimation of Asphalt Pavement Life

924256PDFTech ReportK-TRAN: KSU-97-6Pavement maintenanceMillingOverlays (Pavements)Asphalt concrete pavementsPavement layersFatigue testsPavement distressBenefit cost analysisRehabilitation (Maintenance)Service lifeHossain, MustaqueWu, ZhongKansas. Dept. of TransportationNTL-HIGHWAY/ROAD TRANSPORTATION-Construction and MaintenanceNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceNTL-PLANNING AND POLICY-Management SystemsUS Transportation CollectionThe milling of asphalt concrete (AC) pavement surface refers to the mechanical removal of a part of the pavement surface. The Kansas Department of Transportation (KDOT) and the Kansas Turnpike Authority (KTA) routinely mill the surfaces of some AC pavements before inlaying. KTA has adopted a strategy of recycling the upper pavement layer on a relatively frequent basis (every six or seven years) to maintain a smooth riding surface for the last decade or so. However, in most cases, the milling depth is selected based on the rule-of-thumb or experience of the agency for a specific surface distress, such as rutting or transverse cracking, rather than based on any engineering analysis. In this report, the structural and functional performances of such mill-and-inlay AC pavements were analyzed for six different routes of KDOT and KTA. All test sections were tested with the Falling Weight Deflectometer (FWD) at 50 to 100 feet intervals before milling, after milling, and after inlaying. Ten six-inch wide, eighteen-inch long, full-depth asphalt concrete beams were sawn from four test sections. Fatigue tests were conducted in a third-point flexural loading fashion on those field beams sawn into fatigue test specimens of size: 4-in. wide, 3-in. deep and 16-in. long. Distress models and rational transfer factors were found through the analysis of fatigue test results, deflection data, and historical traffic data to estimate the fatigue damage, functional performance, and rutting susceptibility of the mill-and-inlay pavements. For high traffic pavements, an optimal mill-and-inlay depth based on fatigue can be found. Mill-and-inlay strategy may reduce fatigue life of pavements with low traffic volumes. Cost-effectiveness of the mill-and-inlay strategy is higher for pavements with higher traffic. The strategy did not appear to be susceptible to rutting nor did it appear to cause damage to the existing pavement layers.11 Tables, 17 figures, references, 2 appendices. 1505k, 84p