Robert Q. Kluttz

Long term performance of a highly modified asphalt pavement and application to perpetual pavement design

This paper reports on the final surface characterization and full forensic analysis of a highly modified asphalt pavement versus conventional Hot Mix Asphalt (HMA) at the National Center for Asphalt Technology (NCAT). The highly modified asphalt pavement is 20% thinner than a series of companion sections. The sections were subjected to 20 million Equivalent Single Axle Loads (ESALs) over a period of 5 years. At the end of two full track cycles, the thinner highly modified section has outperformed the others in permanent deformation and bottom up fatigue cracking. Modeling results give quite reasonable agreement with observed performance. The performance results validate pavement modeling reported at the International Conference on Perpetual Pavements (ICPP) in October and demonstrate that substantial thickness reduction is possible while retaining and even improving long term performance. Equally important, material properties of highly modified mixes may be used to adjust the damage model calibration factors in the AASHTOWare/r/ Pavement ME Design software so that appropriate pavement thickness can be determined through rational design. This methodology has been put into practice and so far the performance results on commercial projects have validated the design predictions.