Study on the Properties of Waterborne Polyurethane Modified Emulsified Asphalt

摘要

Waterborne polyurethane (WPU) has the advantages of high mechanical strength, strong adhesion, good flexibility, and so forth, which can significantly enhance the mechanical properties and durability of emulsified asphalt and micro-surfacing mixture. This study provides a preparation method of WPU modified emulsified asphalt, and its microstructure, tensile mechanical property, and rheological property were investigated. The results showed that the tensile strength and elongation at break increase greatly when the content of WPU was more than 10 wt％. However, phase transformation occurred when the content of WPU exceeds 30 wt%. The results of temperature sweep test indicate that the complex shear modulus (G*) of asphalt improved obviously and the phase angle (5) decreased with the increase of WPU content, which shows that both the high and low temperature performance of WPU modified emulsified asphalt have enhanced. The relationship between the loss modulus, storage modulus, phase angle, and load frequency in frequency sweep test shows that the viscosity and elasticity of the asphalt enhance with the increase of WPU content, especially at low frequency and high temperature.