Evaluation of the Effect of Aircraft Tire Inflation Pressure on Thin Asphalt Pavements

Abstract

Sixteen nonstandard asphalt pavement test items were subjected to accelerated traffic testing to determine whether reductions in aircraft tire inflation pressure had a meaningful effect on pavement performance. Materials evaluated included a strong and weak base course (limestone and gravel), three asphalt thicknesses (2.5 cm, 3.8 cm, and 6.3 cm), and two aircraft types (C-130 and C-17). Each single-wheel aircraft tire was operated at two tire inflation pressures, that is, normal operating pressure and approximately 20% below normal, while maintaining total wheel load. Rutting behavior and surface cracking were the primary measured distress mechanisms and were used to evaluate pavement performance. It was found that reducing tire inflation pressure on the weak base course materials had little effect on rutting performance, suggesting that total load rather than tire pressure dominated performance. Conversely, tire pressure reductions on strong base course materials provided an improvement in rutting performance ranging from 15% to 73%. Improvement in surface cracking was observed in some cases with a reduction in tire inflation pressure; however, a meaningful amount of surface cracking was not observed in most test items until near or after 25.4 mm of rutting. Thus, it can be concluded that the primary mode of failure was pavement rutting rather than extensive fatigue cracking. Overall, it was found that a reduction in tire pressure on competent aggregate base improved pavement performance, which could permit increased aircraft operations on thin flexible airfield pavements.