CASE STUDIES OF PAVEMENT PERFORMANCE--PHASE II--TEXAS

This report is a final report resulting from case studies of pavement performance conducted by the U.S. Army Engineer Waterways Experiment Station under contract order with the Office of Research of the Federal Highway Administration. The objective of this study was to identify the causes and mechanisms associated with cracking and rutting of flexible highway pavements. This objective was approached through in situ field investigations, laboratory testing, and theoretic analysis. Field tests were accomplished at two test locations--one on Highway 69 near the town of Lufkin and the other on Highway 79 near the town of Buffalo. A test trench was opened at each site, and tests including CBR, moisture, density, cyclic plate tests, vibratory measurements, and surface profile were conducted. Laboratory tests were performed on sampled materials of pavement, base, and subgrade. Resilient and creep characteristics of materials were developed and used to evaluate the existing prediction techniques. Values of measured deflections and those obtained from layer system analysis techniques were generally in good agreement. However, present analysis techniques are not sufficiently advanced to account for all the mechanisms of pavement behavior contributing to the accumulative effects of cracking and rutting of the pavement. This suggests that additional damage models should be developed to supplement and advance present layer system analysis techniques. /FHWA/