Information was collected from each of the six states in Region 5 of the Federal Highway Administration (FHWA) on the procedures used to rehabilitate jointed concrete pavements. As built plans and specifications were obtained from a number of projects in each of the six states which had been rehabilitated and the performance of the pavements were studied after a number of years in service. Interviews were conducted with personnel of the Departments of Transportation from each state to collect as much information as possible concerning the current practices and techniques used for pavement rehabilitation. Where sufficient data were available, statistical correlations were made of the performance trends as they relate to specific rehabilitation practices. Current practices were compared with earlier practices and efforts made to determine the reasons for the changes. Results show that the performance is closely related to the workmanship in the field and the ingenuity of the engineers involved. Recommendations are presented for each of the rehabilitation techniques studied. Many problems still exist with all of the techniques studied. Further detailed data on the exact procedures and practices used in the field during the rehabilitation and performance after rehabilitation are desperately needed. Better record keeping is sorely needed on both the "as built" conditions and on the performance, so the effectiveness of the various practices can be documented.

Load transfer restoration (LTR) is a rehabilitation technique for increasing the load transfer capability of existing jointed portland cement concrete pavement by placement of dowel bars or other mechanical devices across joints and/or cracks that exhibit poor load transfer.

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.