Assessment of the Effect of Aging on Asphalt Mixtures in Egypt: A Case Study

Aging significantly affects the rheological properties of asphalt mixtures and hence the performance of the asphalt pavements. This study presented a case study on the effects of field aging on the performance of asphalt mixtures over time in Egypt. Four samples were extracted from the selected field test section with different service times. Raw materials used in this study were also collected for fabricating laboratory specimens in accordance with selected LTA protocols. The Marshall and Wheel Tracking tests were carried out to assess the evolution of mixture stiffness and rutting resistance with field and laboratory aging. Test results indicated that the laboratory long term aging (LTA) protocol of one day at 85°C, three days at 85°C and five days at 85°C were representative of in-service field aging equivalent to 6, 11, and 14 months, respectively for mixture stiffness and rut depth values. Therefore, the LTA protocol specified in AASHTO R30 did not sufficiently simulate field aging for 5–10 years after placement and compaction as expected.