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Development of a Balanced Mix Design Method in Oregon

项目名称：	Development of a Balanced Mix Design Method in Oregon
摘要：	Cracking 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 and rutting resistance of the pavement through use of low-cost and efficient testing procedures that can be implemented easily. ODOT Research Projects SPR785 and SPR797 (Coleri et al. 2017a and Coleri et al. 2017b) constructed the beginnings of a performance-based balanced mix design method for Oregon. It was suggested that semi-circular bend (SCB) and flow number (FN) tests are the most effective cracking and rutting performance tests that can effectively be used for balanced mix design. It was determined that typical flexibility index (Fl), an energy parameter calculated using SCB test results, values for production mixtures (plant-produced) range from 9 to 14. However, more experiments need to be conducted to determine exact threshold for FI that will provide acceptable long-term pavement cracking performance. For highways with high traffic levels (ESALs > 30 million), an FN of 740 was suggested by AASHTO TP79-13 (2013) and used in SPR785 and SPR797 as the threshold value for rutting performance acceptance. However, FI and FN threshold numbers used in these two research projects were not validated using measured field performance or extensive laboratory testing. In addition, mix design strategies suggested in SPR 797 (high RAP mixtures with different binder contents and binder types) were not validated by plant sampling, laboratory testing, and pilot section construction and performance monitoring.
状态：	Active
资金：	85000
资助组织：	Federal Highway Administration
管理组织：	Oregon Department of Transportation
项目负责人：	Shippen, Norris
执行机构：	Oregon State University, Corvallis
主要研究人员：	Coleri, Erdem
开始时间：	20171001
预计完成日期：	20200630
实际结束时间：	0