Laboratory Investigation of the Adhesion and Self-Healing Properties of High-Viscosity Modified Asphalt Binders

Abstract

Water damage often occurs on porous asphalt pavement during service life because of the well-developed pore structure. Determining the adhesion and adhesion healing properties of high-viscosity modified asphalt (HVMA) under water condition is beneficial to understand the water damage process of porous asphalt. In this study, the modified binder bond strength test was first conducted to investigate the adhesion property and self-healing behavior of HVMA at different conditions. Then, the surface energy test was carried out to further characterize the differences in adhesion property of HVMA. Moreover, the gel permeation chromatography test and fluorescence microscopic test were used to investigate the influence of chemical composition and polymer morphology on the adhesion property of HVMA. Results show that the presence of water reduces the adhesion property of HVMA. The addition of polymers leads to an increasing adhesion strength and a decreasing self-healing ability of HVMA. The self-healing ability of HVMA improves with the increase of temperature, but also shows a decreased trend when the healing time is long at high-temperature water immersion. The effect of polymers on the adhesion property of asphalt has two aspects. First, the swelling of polymers leads to an increasing content of polar heavy components in HVMA, thus enhancing polarity adsorption between asphalt and aggregate. Moreover, a polymer-centered interfacial diffusion layer can be formed during the adsorption of light components, which increases the overlapping area of structural asphalt between adjacent aggregates. This can also improve the adhesion property at the asphalt–aggregate interface.