Performance of polyurethane modified asphalt and its mixtures

Polymer modified asphalts are used to improve the performances of asphalt pavements. However, storage stability and aging performance need to be improved. Therefore, in this study, we focused on assessing the characteristics of polyurethane (PU), base or styrene-butadiene-styrene (SBS) modified asphalt and its mixtures. Polyurethane modified asphalt was prepared using a disk-based serrated mixer. The basic technical index tests of the selected asphalts were performed and bending beam rheometer (BBR), dynamic shear rheometer (DSR), Fourier transform infrared spectroscopy (FTIR) and dynamic mechanical analysis (DMA) were conducted. The property tests of the three asphalt mixtures were also performed. In addition, the approximate capital costs of PU modified asphalt mixtures were calculated. Results of this work demonstrated the high temperature and water resistance of PU modified asphalt. However, PU modified asphalt mixture had a lower low-temperature resistance than SBS modified asphalt, but greater than base asphalt. PU modified asphalt mixture performed excellent water stability and non-deformability. The optimal asphalt content of PU modified asphalt mixture was lower than other asphalt mixtures by 5%. The cost of PU modified asphalt mixtures was similar to that of SBS modified asphalt, indicating that it was a cost-effective material.