Performance Evaluation of the Impact of Modified Silica Nano-Materials on the Hydrophobicity of Hot-Mix Asphalt

There have been many problems associated with the application of traditional methods such as use of sodium chloride (NaCl) for anti-icing asphalt binder in order to prevent asphalt icing. Among the disadvantages of using this type of materials is their incompatibility with the environment, which leads to drying the vegetation around the roads, corrosion of vehicles' metal parts, and many damage to the structural parts of pavements. Consequently, the asphalt binder's friction and resistance are reduced. Today, use of nano materials in asphalt and bitumen industries has attracted the attention of many researchers and scientists. In this paper, for hydrophobicity of the asphalt binder during rain, a type of bitumen coating modified with nano silica was used. The results of wheel-track testing and skin friction test on asphalt slabs with hydrophobic coatings showed that these coatings could generate hydrophobicity property and also reduce the rutting depth of asphalt mixtures. Moreover, its hydrophobicity property could prevent the formation of hydro-planting phenomenon of moving vehicles during rain, which itself is a factor contributing to road surface safety. Finally, by comparing this method with other conventional hydrophobicity methods in economic and technical terms, it can be introduced as a modern method with minimum negative impact on the environment.