Performance Evaluation of Military Airfield Pavement Drainage Layers

A performance evaluation of drainage layers was conducted during the period of July to November 2008 at three U.S. military installations to determine if the in-place performance justifies their required use on military airfield pavements. Evaluation procedures included the artificial introduction of water into the pavement structure and observation of outflow. Flow and time measurements were recorded and analyzed to determine if the provided permeability of each drainage layer satisfies the current design criteria. Results from this evaluation showed that design and construction, as well as maintenance have important roles in the functionality of airfield pavement drainage layers. Several pavement areas tested were not functioning properly. However, permeability rates through the drainage layers meeting the aggregate gradation specifications were within acceptable limits. It was concluded that the use of drainage layers in military airfields is beneficial, but should be required only on areas where climatic conditions represent a potential of water entering and causing problems in the pavement system. Historical pavement surface condition data were also analyzed, but not enough surface deterioration was observed because the drainage layers studied had not been in place long enough to show any differences in performance from pavements constructed without drainage layers. An additional evaluation of long-term pavement performance was recommended to be considered in the future.