Full-scale experimental testing of unbonded concrete overlays was undertaken at the Federal Aviation Administration's National Airport Pavement Test Facility, under a project sponsored by the Innovative Pavement Research Foundation. Three experimental test items with different thickness configurations were constructed and trafficked until failure. The unbonded concrete overlay was separated by an asphalt interlayer from the underlying pavement slab. As a part of this study, several concrete slabs were instrumented with linear position transducers (LPT) to monitor the vertical movement of the slabs in response to environmental and traffic loading. The relative movements of the slabs in response to environmental and applied loads were also evaluated for this same period. LPT gage responses indicated an increased magnitude of downward movement at slab corners relative to the midslab position. However, both corner and mid-slab locations exhibited a steady cumulative downward movement with increasing load when compared to an initial reference position.