Airfield Repairs in Austere Locations Using Pelletized Asphalt Technology

The use of pelletized asphalt technology to produce airfield-quality hot-mix asphalt (HMA) is evaluated in this study. The pelletization process produces HMA mix components (asphalt cement, fine aggregate, fiber, and polymer) as a pre-manufactured product that can be shipped at ambient temperature to austere locations. There, it can be introduced to locally-produced, heated coarse aggregate in a continuous or batch plant. Two HMA mix types known to provide high shear and rutting resistance were designed and subjected to laboratory tests; one was the stone mastic asphalt (SMA) mix and the other was a dense-graded airfield (DGA) HMA mix. Laboratory tests using the asphalt pavement analyzer indicated that DGA mixes had better rutting resistance compared to the SMA mixes. Thus, the test sections (one pelletized mix and one conventional HMA mix) at Silver Flag Test Area were built using the DGA mix gradation. The conventional HMA mix served as the experimental control. The test sections were trafficked with 1,500 passes of the F-15E load cart to evaluate the rutting performance of the pelletized asphalt HMA. The pelletized asphalt HMA section showed no rutting. The conventional asphalt test section, on the other hand, exhibited as much as 22 mm of rutting. The study concluded that it is feasible to produce airfield-quality HMA with pelletized asphalt using conventional HMA plants. Conventional construction equipment was adequate for placing a durable and rut-resistant pelletized HMA pavement. This paper presents results of laboratory and field tests and provides status of field implementation of the technology.