This article aims to demonstrate the advanced features of two second-generation mechanistic-empirical (ME) pavement analysis engines by focusing on their ability to conduct fatigue performance analysis. First, a comprehensive review is presented of both mechanistic and empirical damage models, underlining the additional features of CalME and FlexPAVE™ over AASHTOWare Pavement ME Design. Then, the capabilities of these methodologies are demonstrated by simulating the fatigue damage performance of an example study section. For these simulations the mechanical properties of four asphalt concrete mixtures, assembled in the laboratory with similar mix design attributes but diverse fatigue characteristics, were utilized. The empirical transfer functions were initially calibrated against field cracking for the unmodified mixture cracking predictions. After that, fatigue damage simulations for the other three mixtures were performed. The results showed a similar ranking in fatigue cracking performance for both software simulations. Polymer-modified mixtures exhibited higher fatigue cracking resistance, whereas the unmodified mixture showed the worst cracking resistance. However, significant differences in cracking initiation and progression rates were observed for all mixture simulations before and after calibration. This discrepancy was related to the different approaches to considering traffic loads in each software system, single axle in FlexPAVE™ and axle spectrum in CalME. Finally, current, and future enhancements for both analysis engines are briefly discussed.

Key words: pavement, fatigue performance, simulation