Development of the Airfield Asphalt Binder Selection Tool

Abstract: The durability and performance of flexible airport pavements are critical to ensuring safe and efficient air travel. The selection of asphalt binders plays an important role in achieving these goals, as the binder's properties significantly influence the pavement's ability to withstand heavy aircraft loads, environmental conditions, and the rigors of daily operations. Choosing an asphalt binder can dramatically affect the pavement's resistance to common forms of distress, such as rutting, fatigue cracking, and low-temperature cracking. However, selecting the correct binder is not a straightforward task. This selection process can be challenging, particularly for those with limited experience in asphalt technology, leading to potential performance and cost issues if the wrong asphalt binder grade is chosen. To address these challenges, the Airport Asphalt Pavement Technology Program (AAPTP), as part of a cooperative agreement with the National Asphalt Pavement Association (NAPA) and the FAA, sponsored a study to develop an airfield asphalt binder selection tool. The tool aims to provide a fast, standards-compliant method for identifying appropriate and specified asphalt binder grades for civilian and military airfield asphalt projects in the U.S. states and Canadian provinces to indicate whether additional testing or binder modification is required. The tool operates by first determining a base asphalt binder grade based on environmental conditions (climate), which is typically selected based on standard grades used in the project's location. From there, the tool applies a series of scenario-specific adjustments, considering factors such as aircraft gross weight, speed and pavement layer (FAA projects), aircraft tire pressure (DOD projects), and the use or not of recycled asphalt materials (RAP). The result is a recommended binder grade that meets the performance requirements and is locally specified. If an asphalt binder that is not routinely specified is recommended for a project, the tool will guide the design engineer on how to get it. In the broader context of airfield pavement design, this tool exemplifies how technology can be leveraged to improve decision-making processes, leading to better outcomes in terms of both performance and cost. As airports continue to face increasing demands from heavier aircraft and more intense traffic patterns, the importance of selecting the right materials will only grow, making the tool a valuable resource that presents a practical solution to the challenges involved in designing flexible airport pavements.