Research on rheological properties and modification mechanism of waterborne polyurethane modified bitumen

•Waterborne polyurethane (WPU) additives were prepared and employed to modify bitumen.•The rheological properties of WPU-modified bitumen were investigated.•The modification mechanism of the WPU on virgin bitumen was analyzed.•Two-phase structure of the WPU is the key to enhancing the high-and-low temperature performance of bitumen.