National Concrete Pavement Technology Center

Project description

Faulting of joints has been observed to be a common distress in Bonded Concrete Overlays on Asphalt (BCOA). However, faulting is not considered in any of the current design procedures for BCOA. Faulting is caused by pumping forces which remove supporting materials either at the bottom of the overlay slab within the asphalt layer or below the asphalt in the granular layer. This location is dictated by the depth of joint propagation. Current faulting design procedures, such as those incorporated into Pavement ME, were developed considering only jointed plain concrete pavements (JPCP). It is possible to use the current design software to predict joint faulting for full-lane width BCOAs, but it is calibrated with JPCP faulting data. JPCPs are typically thicker than BCOAs and have longer panel lengths. There are also a number of equivalency concepts employed in the Pavement ME to simplify the analysis, including equivalent thickness, equivalent temperature gradient, and equivalent slab that are not appropriate for BCOAs. Work is underway at the University of Pittsburgh to incorporate a faulting model into the BCOA-ME design procedure. That work is being funded by PennDOT and focuses on the impact of the climate in Pennsylvania. To adopt this for NRRA member states, a significantly larger range of climatic conditions must be consider. The proposed work will be performed so that the faulting model developed under the PennDOT project can be expanded to include climate stations in NRRA member states.