Design Process of Asphalt Mixture Incorporating Compaction-Effort Variable: Fid-Bau Portal

Design Process of Asphalt Mixture Incorporating Compaction-Effort Variable

Zhang, Yining / Sun, Lijun / Luo, Dong

The Superpave mix design is a process of repeatedly optimizing the aggregate gradation and asphalt content in accordance with specified limits. As one of the important design parameters, the number of design gyrations ( $N_{des}$ ) is adopted empirically to be a fixed number under a specific traffic level. Based on the concept of a performance-oriented approach, this study regarded $N_{des}$ as a variable design parameter and evaluated the influences of two design cases on the performance of asphalt mixture: $N_{des}$ variables and asphalt content (gradation unchanged) and $N_{des}$ variables and aggregate gradation (asphalt content unchanged). Two groups of experiments were designed. The first group used $N_{des}$ levels of 50, 75, and 100 gyrations, and less asphalt content was adopted with a higher $N_{des}$ . The second group used compaction levels of 50, 75, 100, and 125 gyrations, and coarser aggregate gradation was adopted with a higher $N_{des}$ . Both groups of experiments showed that with an increase in $N_{des}$ , rutting performance was increased and low-temperature performance was decreased. In addition, in the former group of experiments, fatigue performance was decreased with the increase of $N_{des}$ . Following these rules, this paper took Hainan province mix design as a case, and $N_{des}$ was optimized to meet requirements. It can be seen that regarding $N_{des}$ as design variable is necessary and can improve flexibility in the design.