FOURTH CYCLE OF PAVEMENT RESEARCH AT THE PENNSYLVANIA TRANSPORTATION RESEARCH FACILITY, VOLUME 6, DEVELOPMENT OF MATERIAL STRUCTURAL COEFFICIENTS AND EVALUATION OF MATERIAL BEHAVIOR. FINAL REPORT

Pavement performance and material behavior were monitored throughout the fourth cycle of research at the Pavement Durability Research Facility. Condition surveys, roughness measurements, deflection measurements, and core samples were taken periodically during the test period. Values of presnet serviceability index (PSI) were determined from profilograph measurements and condition survey data. Structural numbers were determined through a least squares analysis that was used to fit the PSI versus EAL curve for each section. Structural numbers greater than about 5.0 were found to represent pavement sections that were still in the relatively "flat" portion of the PSI deterioration curve at the end of testing. Structural numbers for those sections could change after more traffic applications. Structural coefficients for FJ-1 and ID-3 wearing course, cold-recycled base course, and the open-graded subbase materials were determined by comparing the performance of pavement sections incorporating the new materials with the performance of various control sections. A detailed and comprehensive laboratory investigation was performed to document and evaluate the mechanistic behavior of the pavement materials. This information permits a better evaluation of the performance of the pavements.