Antiaging Effects of Linear Alkyl Benzene Sulfonic Acid Utilization on Bitumen Modification

Abstract

The manufacture of asphalt pavements causes various environmental problems due to bitumen’s hazardous nature. Aging of bitumen yields undesirable properties, which may cause several adverse effects on asphalt performance. Use of antiaging agents for bitumen modification results in improved aging resistance, hence such agents confer environmental benefits by reducing the consumption of bitumen owing to lower maintenance requirements and the reduced volume that needs to be produced. Therefore, it is important to develop new antiaging agents and investigate their benefits to the asphalt industry. This study investigated the use of different rates (1%, 2%, and 3%) of linear alkyl benzene sulfonic acid (LABSA) as a bitumen antiaging agent through chemical and rheological characterization on unaged, short-term-aged, and long-term-aged samples using Fourier transform infrared spectroscopy and dynamic shear rheometer (DSR). A chemical aging index (CAI) and various rheological aging indexes, obtained by the construction of master curves and crossover temperatures were calculated to evaluate the variation of aging effects by LABSA addition. The detailed experiments showed that LABSA-modified samples exhibited better aging resistance compared to neat (base) bitumen. Additionally, the statistical analyses of all aging indexes were investigated to obtain the relationship between chemical and rheological aging indexes. The determination coefficient (R2) and scatter index (SI) results showed that the rheological behavior of bitumen against aging could be evaluated based on chemical behavior and vice versa. Moreover, it was concluded that short-term aging and long-term aging effects should be evaluated separately to determine the relationship between different aging characteristics of samples.