Adjusting Asphalt Mixes for Increased Durability and Implementation of a Performance Tester to Evaluate Fatigue Cracking of Asphalt

016598072018Final ReportPDFTech ReportFHWA-OR-18-06SPR 785Asphalt concreteAsphalt mixturesDurabilityFatigue crackingHot mix paving mixturesLife cycle costingMechanistic-empirical pavement designPavement performanceRecycled materialsDesignHighwaysMaterialsPavementsFatigue crackingtop-down crackingpavement durabilityrecycled asphalt pavementsmechanistic-empirical designpolymer modified hot mix asphaltlife-cycle costUnited StatesOregonOregon. Dept. of Transportation. Research SectionColeri, ErdemSreedhar, ShashwathHaddadi, Sogol SadatWruck, BlaineOregon State University. School of Civil and Construction EngineeringOregon. Dept. of Transportation. Research SectionUS Transportation CollectionCracking is a common failure mechanism in asphalt concrete pavement structures. It is one of the main reasons for large road maintenance and rehabilitation expenditures, as well as reduced user comfort and increased fuel consumption due to high road roughness. The resistance of the pavement to this distress mechanism is dependent upon the ductility of the asphalt pavement mixture. The use of recycled asphalt materials in asphalt mixtures are also becoming increasingly common. A drawback of this practice is a reduction in ductility of the asphalt mixture, which causes a significant reduction in the fatigue life of the pavement in many cases. In Oregon, asphalt pavements are commonly failing prematurely due to cracking-related distresses, necessitating costly rehabilitation and maintenance at intervals of less than half of the intended design lives in some cases. For this reason, it is necessary to accurately quantify the impact of increasing the recycled asphalt content in asphalt pavement on the structural cracking resistance of the pavement through use of low-cost and efficient testing procedures that can be implemented easily. This study focuses on characterizing the cracking performance of asphalt pavements in Oregon by considering four tests commonly used to evaluate fatigue cracking resistance and proposing implementation of the most cost-effective and efficient test procedure for agencies and contractors. Also, the impact of asphalt mixture properties, such as binder content, air-void content, aggregate gradation, polymer modification, and aging, on cracking performance of asphalt mixtures was investigated. Mechanistic-empirical (ME) design modeling and life-cycle costs analysis were also conducted to determine cost and performance effectiveness of asphalt mixtures with varying properties. Finally, recommended strategies were proposed for Oregon to address the issue of early pavement fatigue failure based on the test results, statistical analysis, ME models, and life cycle cost analysis (LCCA). The goal of this study is to provide a better decision-making structure during the pavement design stage to address fatigue cracking susceptibility, with the intent of avoiding premature pavement failure and expensive early maintenance and rehabilitation. Additionally, the study aims to reliably facilitate an increase in recycled materials content in asphalt pavement through advanced testing procedures and design recommendations proposed in this study. These recommendations will reduce the life cycle cost of pavements in Oregon, reduce network-level pavement roughness and increase the sustainability of the paving industry