Effects of rejuvenators on high-RAP mixtures based on laboratory tests of asphalt concrete (AC) mixtures and fine aggregate matrix (FAM) mixtures

This paper presents the effects of various rejuvenators on the mechanical characteristics of the asphalt mixtures containing a high percentage of reclaimed asphalt pavement (RAP). Laboratory tests were performed using two different scales of laboratory samples: asphalt concrete (AC) and fine aggregate matrix (FAM) samples with 65% RAP and three different types of rejuvenators chosen from different production technologies. The results of experimental tests on viscoelastic stiffness, cracking behavior, and the permanent deformation of asphaltic materials in both the AC and FAM mixtures were compared. The test results showed rejuvenator-specific effects on the mixture properties, as well as damage-induced performance behavior in both testing scales (AC and FAM). More specifically, rejuvenators generally increased the ductility of the high-RAP mixtures, resulting in their improved cracking resistance of asphalt mixtures. Regarding the linkage between the performance characteristics of the AC mixture and its corresponding FAM mixture, for the all three aspects—stiffness, fatigue cracking, and permanent deformation—the FAM test results generally correlated with the AC test results. This implies that FAM testing could provide key information for predicting the behavior of the AC mixture and thereby act as an efficient tool for screening materials.