Changes of components and rheological properties of bitumen under dynamic thermal aging

Abstract

Bitumen material is inevitably affected by environmental factors in the process of use, which leads to bitumen aging or oxidation, thus accelerating the performance deterioration of asphalt pavement. However, the traditional aging method has carried out under a specific constant temperature, which cannot simulate the aging behavior of bitumen under dynamic thermal change. Therefore, three dynamic thermal aging processes at different temperatures were selected to simulate the aging process of bitumen under thermal dynamic change in this work. Thin-layer chromatography with flame ionization detection (TLC-FID), Dynamic shear rheometer (DSR), Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and Atomic force microscopy (AFM) were utilized to test the components, rheological properties, prominent functional groups and microstructure of bitumen under different aging conditions. The results show that with the increase of aging cycles, the content of saturates and aromatics components in bitumen decreases, and the content of asphaltenes increases obviously under the higher temperature range for aging cycles. Secondly, the aged bitumen gradually hardens and becomes brittle, especially under the dynamic thermal of the peak temperature of 200 °C, the deterioration of bitumen performance after 20 cycles exceeds the impact of TFOT for 15 h. In addition, for bitumen, dynamic thermal aging is also a thermal oxygen aging behavior, and the roughness and altitude of the bee structure decrease. Overall, this work provides some new ideas for the aging behavior of bitumen under dynamic thermal changes.