Impact of structure, material properties, temperature curling, and trafficking on load transfer efficiency

This study examines the impact of structure, material properties, temperature gradient and trafficking on load transfer efficiency of rigid airfield pavements. The current FAA mechanistic design procedure for rigid pavements assumes constant stress-based load transfer efficiency (LTE (S)) of 25% at the joints. The design procedure assumes the material properties remain constant throughout the life of the pavement. Furthermore, the design procedure does not directly consider the effect that temperature induced slab curling can have on joint LTE (S). Analysis is conducted from full scale accelerated pavement test data from the National Airport Pavement Test Facility (NAPTF) operated by the Federal Aviation Administration (FAA). LTE (S) is determined through strain measurements from gages embedded near pavement joints throughout trafficking of both Construction Cycle 2 and 6 (CC2 and CC6) at the NAPTF. Heavy weight deflectometer (HWD) tests conducted on the test items are used to determine deflection based joint load transfer efficiency (LTE (delta)) and for back calculation of pavement layer stiffnesses. The FAA\u27s finite element analysis program FEAFAA was used to analyze temperature effects on LTE(S) at the joints. This analysis has shown that LTE (S) varies and is sensitive to pavement structure, material properties, temperature gradient throughout trafficking, thus warranting further examination of 25% joint load transfer value