Implications of Incorporating Geosynthetics in Airfield Pavements

Abstract A majority of literature indicates that geosynthetic inclusion in flexible pavement bases, subjected to highway loading, improves performance by reducing rutting or vertical pressure on weak subgrade layers. Instances where geosynthetics were less successful in highway pavements included strong subgrade soils and/or thick pavement layers. Thus, understanding the improvement that can be expected from geosynthetic inclusion in airfield pavements, that are often more substantial than highway pavements, requires an evaluation of existing airfield pavement assets and design methodology. To achieve this objective, a number of tasks were performed: 1) review of in-service pavement thickness and subgrade strength to quantify military airfield pavement characteristics, 2) review of current Department of Defense (DOD) design methodologies to determine if geosynthetic inclusion can be adequately characterized in existing design procedures for new airfields, 3) evaluation to determine if (and in what conditions) an expected performance improvement is financially viable, and 4) implementation in military airfields in manners other than new construction. Results indicated that airfield pavements were generally thicker and stronger than highway pavements, and that in-service airfield pavements exceeded the pavement characteristics where geosynthetics have been identified to provide a meaningful performance improvement. A review of the existing DOD design methodology indicated that any improvement from geosynthetic inclusion in thicker pavements was hidden within the variability of the data used to formulate the existing design methodology. An initial cost evaluation suggested that design life extension (if any) could be the preferred means of quantifying geosynthetic improvement and that the reduction in aggregate thickness attributed to geosynthetic inclusion did not seem to provide an initial cost savings for military airfields. Geosynthetic inclusion in airfield damage repair or as a crack mitigation technique may be more beneficial than aggregate base reinforcement in new construction.