Effect of Laboratory Accelerated Aging on the Mechanical Performance of Asphalt Mixtures Containing Reclaimed Asphalt Pavement

The stiffness modulus is an essential parameter in asphalt pavement design and therefore in the durability of asphalt pavements. This chapter aims to investigate the effect of manufacturing time, short-term and long-term aging on the stiffness modulus of asphalt mixtures, with 35/50 penetration grade bitumen, containing 0% wt., 20% wt., and 40% wt. of reclaimed asphalt (RA). The specimens were manufactured using the Marshall hammer. The asphalt mixtures were aged according to XP CEN/TS 12697-52, in which the loose mixtures were conserved in a ventilated oven at 135 °C for 4 h for short-term aging and then at 85 °C for 9 days to simulate the long-term aging. The indirect tensile stiffness modulus (ITSM) is measured at 15 and 20 °C for the unaged, short-term, and long-term aged asphalt mixtures. The results indicated that there is no effect caused by the variable manufacturing time of six Marshall specimens exposed to high temperatures (160 ± 5 °C), therefore the average stiffness modulus can be considered. For all asphalt mixtures, with and without RA, no significant difference has been observed in the void content after both short- and long-term aging. As demonstrated, asphalt mixtures undergo an increase in the stiffness modulus with aging and RA content. Short-term aging, which represents the mixing, transportation, and laying of asphalt concrete has a significant effect on the stiffness modulus. Moreover, the stiffness modulus seems to reach a plateau value after the long-term aging for all asphalts.