Enhancing Long-Term Performance of Asphalt Mixtures with Amine-Impregnated Zeolite and Postconsumer Plastic

Abstract Moisture-induced damage in asphalt mixtures is a major concern. Lime or liquid amine is often used to reduce the moisture susceptibility of asphalt mixtures. However, lime production is carbon-intensive, and liquid amines are prone to thermal degradation. This study explores sustainable alternatives by comparing the performance of performance grade (PG) 64-16 low-carbon (LC) asphalt binder, incorporating 10% postconsumer plastics, with conventional PG 64-16 binder. Additionally, the performance of amine-impregnated zeolite (AIMZ) as an additive was compared with that of amine and zeolite used separately (AZ) as well as a commercial amine-based liquid antistrip (LAS). Zeolite was suggested to protect the liquid amines from weathering effects. Mixtures with different aging levels were prepared: without aging and with 3, 5, and 7 days of aging. The tensile strength ratio (TSR) was used to evaluate the moisture resistance of the asphalt mixture. The Hamburg wheel tracking test and indirect tensile asphalt cracking test (IDEAL CT) were used to evaluate the rutting and cracking resistance of asphalt mixtures, respectively. The susceptibility to moisture-induced damage and the rheological properties of both types of binder were investigated using the moisture-induced shear-thinning index (MISTI) and the multiple-stress creep recovery (MSCR) test. Mixtures incorporating AIMZ demonstrated better moisture resistance after long-term aging. In addition, the low-carbon binder showed lower susceptibility to moisture damage than the conventional binder. The low-carbon binder also provided enhanced long-term cracking resistance. Rutting resistance was consistent across both binders and all additives. Overall, this study shows that mixture performance should be evaluated across aging progression rather than at a single aging condition.