Evaluation of Balanced Mix Design (BMD) Surface Mixtures with Conventional and High RAP Contents under Laboratory-Scale and Full-Scale Accelerated Pavement Testing (APT)

About the project:

The environmental and economic benefits of using reclaimed asphalt pavement (RAP) in asphalt mixtures have encouraged state agencies to introduce special provisions and specifications allowing its use at relatively higher contents in mixtures. The Balanced Mix Design (BMD) framework provides an opportunity to properly design and produce engineered asphalt mixtures, including those with higher RAP contents (e.g., HRAP mixtures). In addition to performance testing and evaluation in the laboratory, accelerated pavement testing (APT) serves as a valuable tool to evaluate the performance of full-scale constructed pavements in an accelerated manner, as opposed to long-term pavement performance monitoring. In 2020, a collaborative APT experiment was planned and executed with the purpose of evaluating the application of the BMD concept to design durable and longer-lasting surface mixtures in Virginia, with a specific focus on HRAP mixtures. For this experiment, one control and five BMD mixtures were designed and produced; and six lanes were constructed. Rutting and cracking evaluations were conducted per lane. This project covers the following aspects:(a) BMD concept and design of BMD mixtures; (b) Production of mixtures and assessment of the impact of variability on performance as determined by BMD tests; (c) Documentation of construction details and lessons learned for future experiments; (d) Documentation of laboratory performance properties; and (e)Analysis of data generated from the rutting and cracking field studies. The study’s findings will significantly contribute to VDOT's efforts in developing a higher level of confidence in the performance-based thresholds currently used in the BMD initiative within Virginia. By directly implementing the research findings, it will be possible to verify and refine the existing performance thresholds, resulting in a direct impact on BMD specifications and practices.

Project Team

Principal Investigators

Co-Principal Investigators

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