Historical insights on asphalt aging, mechanisms, and anti-aging technologies with evaluation of a potential antioxidant as the way forward

Abstract

Oxidative aging persists as a significant challenge in asphalt binders, substantially affecting the serviceable life of asphalt pavements. Antioxidant additives offer a strategic remedy to mitigate this issue. Significantly reducing or eliminating oxidative aging represents a paradigm shift, extending the longevity of asphalt pavements considerably. This article summarizes the historical trajectory of research on the topic of oxidative aging and antioxidants, with an emphasis on the evolution of the latter. It is followed by findings from a recent study conducted by some members of a global research consortium on the efficacy of potential antioxidants and their underlying mechanisms. Zinc diethyldithiocarbamate (ZDC), identified as a promising antioxidant in earlier phases of this research, was blended with six binders from four different geographic regions. A comprehensive investigation assessed the mechanical, rheological, and chemical characteristics of these blends, utilizing poker chip testing, Dynamic Shear Rheometer (DSR) measurements, polar fraction analysis, and Fourier Transform Infrared (FTIR) spectroscopy. The findings highlight ZDC as an effective antioxidant, significantly mitigating aging across the spectrum of binders. Notably, its incorporation considerably enhances cracking resistance without significantly affecting the rutting resistance. Ongoing innovation and collaboration are essential for integrating promising antioxidants, particularly ZDC, into asphalt pavements, offering immense potential for bolstering the sustainability and resilience of transportation infrastructure.