Interaction of asphalt and water between porous asphalt pavement voids with different aging stage and its significance to drainage

Abstract

Compared with traditional asphalt pavement, porous asphalt (PA) pavement has great advantages in terms of drainage, noise reduction, anti-skid and other functional behavior. More practices have proved that the PA pavement is an important development direction of asphalt pavement. The voids structure of PA pavement can quickly eliminate the precipitation on the pavement, which provides an important guarantee for driving safety in rainy days. However, with the increase of porosity, the contact area between the asphalt on the voids surface and the external environment also increases. Therefore, the aging stage of asphalt plays an important role in the realization of drainage function of PA. In this study, the molecular dynamics (MD) is used to simulate the contact state between water molecules and asphalt surface layer in PA. At the molecular level, the action mechanism between asphalt and water in different aging stages is explained, and the effect of aging on the action of asphalt and water is explored. On this basis, the changes of the interaction between different aged asphalt and water molecules were verified by drip observation (DO) and atomic force microscope (AFM). The results show that the interaction energy between asphalt and water in different aging stages is different. The longer the service life of PA pavement is, the more serious the asphalt aging, and the greater the interaction energy to water molecules is. In the case of large surface area of PA, the interaction between asphalt and water molecules in the aged asphalt can promote the interaction. That is adverse to drainage, thus causing more water retention in the PA structure at macro level. Under the comprehensive action of load, temperature and other factors, water damage of PA pavement structure is caused. The research results have certain theoretical and practical value for promoting the development of PA pavement.