Characterization of Jointed Concrete Pavement Under Daily and Seasonal Temperature Variations Using Rolling Dynamic Deflectometer and Falling Weight Deflectometer Measurements

Pavement temperature is one of the critical factors controlling the behavior and response of a jointed concrete pavement (JCP). Temperature variations cause slab curling and slab expansion or contraction. These changes have a significant influence on the load-transfer condition at joints and cracks in the JCP. A study was constructed to: (1) characterize the response of JCP (at midslabs and joints) under a range of the temperature variations and (2) establish a threshold value in evaluating the severity of movements at the joints. The Rolling Dynamic Deflectometer (RDD) was used to measure continuous deflection profiles under various pavement temperature conditions (daily and seasonally) to evaluate the response of concrete slabs. The RDD is well suited to characterize JCP because the continuous deflection profiles provide 100% coverage along the test path. Since the temperature gradient in the slab controls slab curling, it was found that the motion of slab curling was directly related to testing time and the load-transfer capacity of the joints was significantly increased after around 10:00 a.m. when the curling went from positive to negative. Threshold deflection values were determined by correlating RDD deflections and Falling Weight Deflectometer (FWD) load-transfer efficiency values. Two different deflection parameters were considered: (1) Sensor #1 deflections (W1) and (2) differential deflections between Sensors #1 and #2 (W1-W2). The reliability concept was also incorporated such that pavement engineers can select criteria (based on predefined confidence levels) to identify poorly performing joints.