Evaluation the Rheological Behavior of Asphalt Binder, Fracture Resistance and Moisture Susceptibility of Asphalt Mixtures: Before and After Adding Nano Fe₂O₃

The occurrence of distresses such as rutting, fatigue, thermal and moisture cracks in asphalt pavements has caused that a significant part of the country’s budget is spent annually on the repair and rehabilitation of road pavements. Since it has been proven that the combination of bitumen and aggregates alone cannot provide optimal performance in all loading and weather conditions, the need to modify the asphalt mixture is felt more than ever. In recent years, nanotechnology has become very popular due to its unique properties in improving the properties of bitumen and asphalt mixtures. To this end, the objective of this research is the application of nano-F₂O₃ in improving the performance of bitumen and asphalt mixture against common distresses such as rutting, fatigue, thermal and moisture cracks to suggest a suitable solution based on the results for reducing the probability of the occurrence of these failures in asphalt pavements. In order to achieve the objectives of this research, bitumen was mixed with different percentages of nano-F₂O₃ and subjected to rheological tests such as Dinamic shear rheometer (DSR), Bending beam rheomether (BBR), Muiliple stress creep recovery (MSCR), and Linear amplitude sweep (LAS). The results of this section indicated that the application of 1% nano-F₂O₃ compared to other percentages brought the greatest improvement for the rheological behavior of bitumen. Hence, to measure the resistance of asphalt mixture against thermal and moisture cracking, control asphalt specimens (bitumen without additives) and specimens modified with 1% nano were manufactured, and these specimens were subjected to semicircular bending (SCB) and indirect tensile strength (ITS) tests. The results of this research indicated that adding 1% nano-F₂O₃ can improve the fracture toughness of asphalt mixtures from about 8 to 19%. Moreover, replacing 1% of bitumen with nano-F₂O₃ improves the moisture susceptibility of asphalt mixtures by 9% compared to control specimens.