Using Fine Aggregate Matrix Mix Testing to Characterize Fatigue Performance of Asphalt Mixtures containing Reclaimed Asphalt Pavement

摘要

The Fine Aggregate Matrix (FAM) constitutes the fine portion of the asphalt mix containing binder, fines, and aggregates passing 2.36 mm sieve. Fatigue distresses and crack growth typically occur in the FAM phase of the asphalt mixture; hence FAM mix testing is considered closely representative of fatigue performance. In this study, a FAM mix with 25 percent Reclaimed Asphalt Pavement (RAP) binder replacement was tested and compared with a virgin FAM mix. A tall oil based rejuvenator was used to restore the properties of the RAP mix. Testing was done using a Dynamic Shear Rheometer (DSR) fitted with a solid torsion bar fixture. A linear amplitude sweep test method was devised based on the current AASHTO TP101 standard for binders, with modifications to account for FAM. The viscoelastic continuum damage model was used to calculate the accumulated damage, loss of material integrity and fatigue life. The results show that the rejuvenator helped maintain the integrity of the RAP mix, denoting better fatigue resistance. The rejuvenated RAP mix showed lower accumulated damage than the control RAP mix, however both RAP mixes were inferior to the virgin mix. The fatigue life of the RAP mix was shown to increase slightly with rejuvenation.