Comparison of two pavement rehabilitation strategies

The main objective of the most recent Mobile Load Simulator (MLS) test prog ram was to conduct a comparative study of two rehabilitation processes, Reh abs A and B, constructed on the south- and northbound lanes of US281 near J acksboro, Tex., in 1995 and 1996, respectively. The underlying pavements ha ve composite asphalt layers with the first construction done in 1957. Perfo rmance was evaluated in terms of surface rutting, loss of stiffness in pave ment layers, and permanent deformation in the layers. Tools used during the study included an on-site weather station, nondestructive testing equipmen t (FWD, SPA, PSPA, SASW), and in situ instrumentation (MDD). The findings o f this study provided conclusive results on the relative performance of the two rehab strategies. Rehab A performed well with its sound underlying str ucture. The Dallas District has elected to use this recycling process based , in part, on the results of the MLS tests in Jacksboro. The study serves a s an example of how the MLS program has yielded a variety of products and i ncreased pavement engineering knowledge.