Icing on asphalt pavement may lead to potential hazards for driving safety. To reduce the security risk, this paper aims at preparing a hydrophobic emulsified asphalt coating on asphalt pavement by adding a hydrophobic agent (HPA, Polytetrafluoroethylene powder) to emulsified asphalt. Considering the factors influencing hydrophobic effect, such as roughness of hydrophobic agent, dosage and incorporation method, the ice-repellency of hydrophobic emulsified asphalt coating was characterized by means of contact angle. It was found the hydrophobic properties of emulsified asphalt were significantly affected by roughness, dosage and incorporation methods of HPA and the highest contact angle was 94.3
when the HPA with 1250 meshes and dosage of 15% was added by the external addition method. Through the interlayer shear test and the indoor anti-icing test, hydrophobic asphalt pavement could reduce the bond strength between pavement and ice so that the ice layer could be easily broken and cleared, and the bond strength could be reduced by about 40% at 0.3 kg/m2 dosage of hydrophobic emulsified asphalt. It was proved that the skid resistance performance of the hydrophobic emulsified asphalt coating could conform to the requirements of the specification. The addition of interfacial agent can significantly improve the adhesion between emulsified asphalt and aggregates. These findings demonstrated the potential of using hydrophobic emulsified asphalt coating on highways in adverse weather to provide better anti-icing performance and contribute to traffic safety in winter.

Introduction

After the rain and snow in winter, the accumulated water or snow on asphalt pavement is easy to freeze in the lowtemperature environment, resulting in a sharp decline in the anti-skidding performance of the pavement [1]. On the pavement with ice and snow, the emergency braking distance is greatly increased which poses a serious threat to the safety of life and property of pedestrians and vehicles even causes serious traffic congestion inducing a series of traffic accidents [2]. In view of the icing problems on asphalt pavements, the frequently-used methods of removing ice currently include artificial mechanical snow removal, spraying chloride ice-melting agents, thermal melting technology include microwave heating, thermal cables, solar energy collection technology, and electrically conductive pavements [3–۱۱]. Nevertheless, the methods above will either aggravate pollutants, corrode metal structures, reduce the performance of asphalt binders or be quite expensive. A large number of literatures have shown that hydrophobic surfaces have good hydrophobic and anti-icing properties [12,13]. The larger contact angle and the smaller wetting lag angle can effectively make the droplets rolling and sliding on the surface of the object, thus making it difficult to freeze.