Age-related cracking resistance of waste PET plastic-modified Superpave hot mix asphalt containing rejuvenated RAP

• Age-related cracking resistance of Superpave HMA reduces by adding rejuvenated RAP. • PET modifiers are beneficial for improving the age-related cracking resistance of Superpave HMA. • Relatively finer PET particles gives better age-related cracking resistance. • The negative effect of RAP on the age-related cracking resistance properties of HMA can be countervailed by adding PET modifiers. Superpave hot mix asphalt (HMA), a superior-performing mixture compacted by a Superpave gyratory compactor (SGC) at high temperatures, provides better field performance than the Marshall Mix. Concerning economy and environment, reclaimed asphalt pavement (RAP), from old bituminous pavement can be utilized in the Superpave HMA. RAP carries oxidized bitumen, which has a negative impact on the cracking resistance. Polyethylene terephthalate (PET) from waste bottles can make HMA more resistant to cracking, whereas waste oils used as rejuvenators can make RAP less stiff. The opposite phenomenon of RAP and PET in the cracking resistance cannot be properly addressed by using only one cracking resistance evaluation method. Furthermore, to ensure long-term durability of asphalt pavement, age-related cracking resistance is important. Therefore, in this study, the age-related cracking resistance of PET-modified Superpave HMA containing rejuvenated RAP was evaluated by three methods: Illinois Flexibility Index (I-FIT), Louisiana Semi-Circular Bending (SCB), and Cantabro Abrasion test. To manufacture PET-modified and RAP-added Superpave HMA, 2 % and 4 % PET of two sizes, RAP of 0 %, 20 %, and 40 % rejuvenated by waste oil, and SGC for compaction were used. From the results for the I-FIT and SCB method, 4 % finer PET provided more age-related cracking resistance ability of Superpave HMA without RAP. This value was decreased after adding more rejuvenated RAP. The load-displacement diagram showed that 40 % rejuvenated RAP-added HMA had the stiffest slope and maximum peak load, which indicates the brittleness. However, in Cantabro Abrasion loss, the percentage of material loss was increased with PET and rejuvenated RAP.