Innovative Rheological Modifiers for Decreasing the Cracking Susceptibility of Asphalt Mixtures

Abstract

Incorporating additives into asphalt binders or mixtures to mitigate the adverse effects of aging can improve the resistance to fatigue cracking and, thus, prolong asphalt pavement service life. This study aimed to assess five candidate anti-aging technologies through a comprehensive laboratory testing matrix that can reduce the aging susceptibility and enhance the cracking resistance of asphalt mixtures. Two base binders were modified with the additives. The resultant asphalt mixtures were tested at three aging conditions, including short-term and long-term oven aging and the National Center for Asphalt Technology (NCAT) Accelerated Weathering System. The study assessed the impact of additive technology on cracking performance through dynamic modulus and cyclic fatigue testing. The results were utilized to calculate the S_app and Glover–Rowe mix (G-R_m) indexes to gauge the cracking resistances and aging susceptibilities of the asphalt mixtures. A 20-year pavement structural analysis was conducted using FlexPAVE™ 1.1 software to determine the evolution of each mixture’s percent cracking damage. The results consistently indicated that additives 3, 4, and 5 increased the cracking resistance of asphalt mixtures for both base binders. FlexPAVE™ 1.1 pavement analysis also showed that all tested additives reduced the percent damage over 20 years, except for additive 4 with one of the base binders. Implementing and developing promising additives to counteract aging effects is vital for creating more sustainable and durable asphalt pavements.