Laboratory Evaluation on Pavement Performance of Polyurethane Mixture for Thin Overlay

Abstract

The construction temperature of commonly polymer-modified asphalt for thin overlay is high, and the asphalt is prone to aging, which affects the service life of pavement. In this research, polyurethane (PU) binder was used to replace asphalt to prepare thin overlay mixtures with different gradations at room temperature. The pavement performance of the PU thin overlay mixtures is comprehensively evaluated by comparing with common polymer-modified asphalt mixtures. The results show that the mechanical strength of the PU mixtures is positively correlated with the PU content under the same type gradation. Due to the excellent mechanical strength of PU binder, the mechanical properties and dynamic stability of its mixtures are much higher than that of asphalt mixtures under the same gradation, and the Cantabro loss is also small. Besides, the difference variation is low in water sensitivity between the PU mixtures and asphalt mixtures. The PU mixtures can meet the requirements of low-temperature pavement performance and can also be used in most low-temperature environments. Finally, the evolution model of skid resistance of PU thin overlay mixtures was obtained through accelerated pavement test. It is proved that the PU mixtures have excellent skid resistance and durability. The model can well simulate the development of skid resistance with the number of loading times, which provides a certain reference for research on the durability of polymer and modified asphalt thin overlays.