Volume 39, Issue 3 (May 2011)
Rehabilitation Assessment of Jointed Concrete Pavement Using the Rolling Dynamic Deflectometer and Ground Penetrating Radar
Transportation authorities need tools to characterize the structural conditions of jointed concrete pavements (JCPs) to minimize or, in the best case, prevent premature failures of rehabilitated JCPs. Applications of the rolling dynamic deflectometer (RDD) and ground penetrating radar (GPR) in pavement forensic studies and rehabilitation investigations are presented. The continuous RDD deflection profiles allow the evaluation of mid-slab behavior and load transfer conditions of joints/cracks, while GPR surveys assist in detecting adverse subsurface conditions such as voids and increased moisture. In this paper, the patterns in RDD deflection profiles that represent the four different structural conditions in JCPs are presented and discussed. Then, the results from combined RDD and GPR surveys on two rehabilitation projects are presented. In the first project, the problematic slabs with poor load transfer and high vertical differential deflections are identified in the RDD profile. The GPR survey is used to identify the cause of the high differential deflections, voids filled with water under the slabs. The recommendation is to fill the existing voids by using under-sealing techniques and install dowel-bar retrofit prior to a new overlay. In the Grogans Mill project, the RDD profile shows that the southbound lane has a significant number of slabs with a strong potential for reflective cracking. The GPR data indicated that there is moisture beneath the deteriorated slabs. A reconstruction of the southbound lane is recommended. On the other hand, the northbound lane consists of three subsections that require different rehabilitations: Slab replacement, asphalt overlay, and reconstruction. The success of rehabilitation generally depends on the selection of appropriate treatments. By providing 100 % coverage, both RDD and GPR are effective tools in evaluating existing conditions, and the combination of these tools significantly assists in selecting the optimum rehabilitation treatment.