Effect of Fatigue Damage on Complex Modulus Master Curves of Asphalt-Aggregate Mixes

The objective of this study is to characterize the responses of complex modulus master curves of asphalt-aggregate mixes after fatigue damage. The complex modulus master curve without fatigue damage is used to estimate stiffness under different combinations of loading frequency and temperature for structural and mix design. Fatigue damage causes a loss of stiffness and a change in phase angle. Characterization of the stiffness master curve under different states of fatigue damage is especially important for recursive pavement design analysis, in which the response of the pavement to loading is updated periodically based on previous damage during simulation of its life. This study analyzed two typical asphalt mixes used in California; California Valley AR-4000 (PG64-10) binder and California Coastal AR-4000 (PG64-16) binder. Two air-void contents (5 % and 8 %) were also considered. The genetic algorithm and the Gamma distribution function were utilized as tools to characterize the master curves before and after fatigue damage. From this study, it was found that the fatigue-damaged complex modulus master curves can be expressed reasonably well by modifying the amplitude coefficient of the undamaged Gamma distribution function with a power function of stiffness ratio or simply the stiffness ratio. Hence, the modified Gamma distribution function used to characterize the master curve captures the effects of fatigue damage, as well as loading frequency and temperature. A simplified recursive analysis using Miner’s law was conducted to demonstrate the importance of using the damaged master curve in pavement fatigue performance prediction. The simulation results also indicate that pavement design without consideration of the loss of stiffness due to fatigue damage results in a risky overestimate of pavement fatigue life.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 25p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01044172
  • Record Type: Publication
  • Report/Paper Numbers: 07-3139
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 7:50PM