Rehabilitation of Asphalt Binder to Improve Rutting, Fatigue and Thermal Cracking Behavior using Nano-Silica and Synthesized Polyurethane

The aim of this study was to investigate the behaviour of the binders modified by nano-silica and synthesized poly-urethane. To do so, firstly, the binder was modified by three different percentages of nano-silica and poly-urethane. Then, the asphalt binders were aged in different levels based on the test conditions. The high- and low-temperature performance were evaluated using Multiple Stress Creep Recovery (MSCR) and the Bending Beam Rheometer (BBR) tests, respectively. For investigation the fatigue performance in intermediate temperature, Time Sweep (TS) test was performed. The results indicate that the nano-silica improved the performance of the asphalt binder at high temperatures and lowered the efficiency at low temperatures. The synthesized polyurethane had no effect on the high-temperature performance grade of the asphalt binder. However, it improved the low-temperature performance grade. The results of fatigue test indicate that the effect of polyurethane was better than the nano-silica. Fourier transform infrared spectroscopy test was utilized to investigate chemical properties. Obtained results affirmed the presence of nano-silica and polyurethane bonds. Chemical bonds at low and intermediate temperatures, as well as physical properties and stiffness at high temperatures, play a more important role in the performance of the asphalt binder.