Compatibility and Adhesion Properties of Rubber Asphalt

To research the compatibility and adhesion of rubber asphalt, the correlation of the asphalt components and rubber content with conventional properties of rubber asphalt was analyzed. The effects of asphalt component, rubber content, thin-film oven testing, and ultraviolet (UV)-aging testing on the adhesion properties of rubber asphalt were analyzed by measuring the surface free energy and its component based on the theory of surface free energy. Results show that the three major indicators of rubber asphalt are obviously affected by the properties of matrix asphalt, i.e., rubber asphalt has low penetration, high softening point, and movement viscosity processed by the matrix asphalt with high resin and asphaltene content. With increased rubber content, the penetration of rubber asphalt decreases and its softening point increases, but its ductility value is closer. Viscosity decreases when rubber asphalt is stored at high temperature, and viscosity decreases by 60% when stored for 8 h at 180℃. The surface energy of rubber asphalt increases with increased rubber content. After thin-film oven testing of 5, 10, and 15 h, the surface energy of rubber asphalt increases, but the change rate of surface energy decreases. The effect of UV aging on the surface properties of rubber bitumen is not obvious. The surface energies of rubber asphalt processed by different components of matrix asphalt after 10 and 20 d of UV aging differ.