Investigation on the stability and interaction of asphalt emulsion with waterborne acrylate as pavement maintenance coating

As a kind of organic binder, the asphalt emulsion was encouraged to be applied on the highway and airport pavement surface as a preventive maintenance approach. However, the colloid stability and interaction of the thermodynamically unstable coating was not fully investigated and thus resulted in limited application. This research attempted the waterborne acrylate as a novel modifier for emulsified asphalt coating, and investigated the colloid stability and interaction of emulsified asphalt during the phase separation. Firstly, the viscous flow behavior of the asphalt emulsion with waterborne acrylate was evaluated with viscosity test, with the consideration of the droplets interactions between waterborne acrylate and asphalt. Then laser particle size analyzer was employed to evaluate the particle size of dispersed asphalt particles in the dispersion system. Spectrophotometric analysis was conducted to evaluate the sedimentation rate of asphalt particles with a three-dimensional sedimentation kinetics model of absorbance area. The thin film of emulsified asphalt supernatant after demulsification was observed by the digital microscope. Finally, a three-stage model of curing progress in asphalt emulsion was proposed and statistical analyses were conducted to reveal the correlation between various indices. This study proved that the curing process of different emulsion systems were inconsistent. It was promoted that stability and compatibility investigation of waterborne polymer in asphalt emulsion should be taken into consideration and a substantial incorporation would cause colloid coalescence and droplet aggregation, which ultimately affected the properties and microstructure of asphalt coating.