Environmental laboratory aging of bitumen: Contrasting a parametric approach to field aging

Bitumen aging is a frequently discussed topic among the scientific community. The consensus is that standardized laboratory aging procedures like the Pressure Ageing Vessel (PAV) test do not reflect environmental field conditions, resulting in discrepancies between real-world and predicted aging behavior. Therefore, the Viennese Binder Aging (VBA) method incorporates aging-inducing factors (light, humidity, and reactive oxygen species (ROS)) present in the troposphere into a laboratory setup. This paper uses a parametric approach focused on overall trends to compare the combined and individual effects of these factors on two unmodified binders under different exposure modes. Visual documentation, Fourier Transform Infrared (FTIR) spectroscopy, and Dynamic Shear Rheometer (DSR) results were used to compare VBA aged samples to PAV aged samples and field aged data with varying exposure times. ROS induced strong aging with pronounced visible cracking. Direct light exposure led to the formation of a passivating layer, which reflected field aging well, while indirect light exposure had only limited impact. Water alone did not accelerate aging, but in combination with ROS promoted binder redistribution. While binder A showed no increased aging, binder B showed the overall highest aging degree after exposure to water and ROS. Binder A was most affected by direct light and ROS exposure. These differences highlight the VBA’s ability to distinguish binder-specific sensitivities and to identify the dominant aging drivers across binders. Thus, this study supports the understanding of realistic environmental aging drivers by providing a method that helps bridge the gap between laboratory aging and field aging.