Identification of pavement failure mechanisms at FHWA accelerated loading facility ultrathin whitetopping project.

In 1998 eight test lanes of ultrathin whitetopping (UTW) were constructed over existing hot-mix asphalt (HMA) pavements at the Federal Highway Administration's Accelerated Loading Facility (ALF) located at the Turner-Fairbank Highway Research Center in McLean, Virginia. Various combinations of thicknesses, joint spacings, fiber reinforcement, and types of HMA base were used. In spring 2000 the loading experiment of these pavements was completed, and the analysis of behavior and performance was begun. A summary of some of the pavement distresses observed at the ALF is presented, and hypothesized failure mechanisms are identified, providing an addition to the state of the knowledge with respect to the actual life cycle of UTW pavements.