Investigation of joint transfer characteristics in rigid airfield pavements

Abstract: The capability of a rigid pavement contraction joint to transfer applied aircraft loads is one of the simplifying assumptions in the Department of Defense (DoD) rigid pavement design procedure. The design procedure assumes that 25% of the computed free edge stress on the loaded slab is shared by the adjacent unloaded slab, which may or may not be accurate depending on the joint construction technique. A study was undertaken to investigate the joint behavior of two portland cement concrete pavements of different flexural strength and constructed thickness to gather data to inform actual joint transfer characteristics and to verify a more robust joint modeling approach. A falling weight deflectometer (FWD) was utilized to gather deflection sensor measurements across contraction joints that were constructed with and without dowel bars. The proposed response model consists of two semi-infinite adherent plates connected by an elastic joint with both shear and moment transfer, partially coupled to a multilayered elastic foundation. The field data collected from the FWD indicated that the joint load transfer behavior was sensitive to load intensity, as well as concrete flexural strength, and that the 25% assumption was not appropriate in all cases. Results showed that the joint model provided a reasonable agreement with the field collected data, and could be used to improve DoD rigid pavement design methodology.