Effects of accelerated aging conditions on the assessment of antioxidant effectiveness of asphalt binders

Abstract

Asphalt binders are prone to oxidative aging, which threatens the durability of asphalt pavements. Antioxidants may enhance the aging resistance of asphalt binders, but their performance is influenced by the specific aging methods. To investigate the effects of aging conditions on the assessment of antioxidant effectiveness, this study used three different accelerated aging simulation methods to treat the antioxidant-modified asphalt binders. Four types of neat asphalt binders from different sources were mixed with four antioxidants to prepare the antioxidant-modified asphalt binders. The neat and modified binders (20 combinations) were then subjected to standard aging treatment methods, i.e., rolling thin film oven (RTFO) and pressure aging vessel (PAV), to simulate the aging process. Additionally, an accelerated natural aging (ANA) method was used to characterize the kinetic oxidation process of asphalt binders. The chemical and rheological aging states of binders were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Dynamic Shear Rheometer (DSR), respectively. The test results for antioxidant-modified binders subjected to the RTFO, PAV, and ANA aging methods were compared to analyze the consistency in evaluating antioxidant effectiveness. The comparison showed that the consistency of chemical anti-aging indicators between RTFO and ANA-treated binders was only 25 %, while the consistency between PAV and ANA-treated binders was 60 %. These findings indicate that the assessment of antioxidant effectiveness in asphalt binders is significantly affected by the choice of aging method.