UC Davis

In this study, four plant-produced asphalt mixes were considered to evaluate the performance and construction challenges of mixes containing RAP/RAS. Also, asphalt mixes were collected at two different plant-production times for each mix type to monitor the performance variability between lots. A softer base binder (PG 58–22) was used for mixes with RAS compared to the base binder (PG 64–16) used for the control mix (no RAP or RAS) and the mix with only RAP. Use of small dosages of rejuvenators and the softer binder in the RAS mixes were found to show similar performance compared to the control mix with no RAP or RAS. The results obtained from the extracted binders of these mixes indicate that mixes with RAP and RAP/RAS are expected to show higher rutting resistance and slightly lower low-temperature cracking resistance, also shown in the mix rutting and fracture cracking tests. A similar fatigue life was observed for all mixes at low strain levels in the Four-Point Beam test. However, the mix with both RAP and RAS was found to show better fatigue life at high strain levels. Similar performance test results were observed between different lots of the same mix type for most cases. Finally, there were no problems with field mixing, compaction, or finishing of the mixes containing RAP and RAP/RAS.