Preparation and anti-icing properties of a hydrophobic emulsified asphalt coating

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/m(2) 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. (C) 2019 Elsevier Ltd. All rights reserved.