Performance characterisation of asphalt mixture modified with one-component polyurethane

The use of polyurethane (PU)-modified asphalt for paving purposes has recently gained increasing interest in both academia and industry. This study aimed to characterise the engineering performance of an asphalt mixture modified with one-component PU and explore its adhesive mechanism. To achieve these objectives, PU-modified bitumen and asphalt mixtures with two different PU contents (10% and 30%) were prepared. Various laboratory material property tests, such as rotational viscosity test of the binder, Marshall test, indirect tensile strength (ITS) test, Hamburg wheel-tracking test, moisture susceptibility and indirect tensile fatigue test of the PU-modified mixture, were carried out. Fourier transform infrared spectroscopy was carried out to explore the adhesive mechanism between PU-modified binders and aggregates. The results indicated that the overall performance of the asphalt mixture increased significantly with the PU prepolymer, with increased Marshall stability, ITS and resistance to moisture damage, rutting and fatigue damage. It was found that the PU prepolymer reacted with hydroxyl groups on the surface of the aggregate, which contributed to the improved performance of the asphalt mixture. The findings of this study may facilitate further practical applications of bituminous materials modified with one-component PU in the pavement industry.