Conventional properties, rheological characteristics, and thermal performance of waste polyurethane modified asphalt with butyl rubber

Abstract

To enhance the low-temperature performance of waste polyurethane (WPU) modified asphalt, a composite modifier incorporating butyl rubber (BR) was investigated. In this study, recycled waste polyurethane for industrial filling is selected, which is belonging to the Polyether polyols. Various concentrations of BR were introduced to WPU modified binder, with and without stabilizer. The blends underwent conventional asphalt performance tests, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests. Thermal performance and morphology were analyzed using differential scanning calorimeter (DSC) and fluorescence microscopy (FM). Fourier transform infrared spectroscopy (FTIR) experiments revealed the mechanism of WPU/BR modified asphalt. Results indicated that adding 3% BR to 15% WPU increased ductility at 5 ℃ by over 5 times, elevating the performance grade from PG-22 to PG-28. BR addition lowered the glass transition temperature, enhancing stability at higher temperatures. Besides improving low-temperature performance, BR also enhanced high-temperature performance and deformation resistance. Functional group analysis suggested a chemical modification process. Considering overall performance and modification effects, the optimal composite modifier was found to be 15% WPU and 3% BR.