Physicochemical and Rheological Properties of a Transparent Asphalt Binder Modified with Nano-TiO₂

Transparent binder is used to substitute conventional black asphalt binder and to provide light-colored pavements, whereas nano-TiO₂ has the potential to promote photocatalytic and self-cleaning properties. Together, these materials provide multifunction effects and benefits when the pavement is submitted to high solar irradiation. This paper analyzes the physicochemical and rheological properties of a transparent binder modified with 0.5%, 3.0%, 6.0%, and 10.0% nano-TiO₂ and compares it to the transparent base binder and conventional and polymer modified binders (PMB) without nano-TiO₂. Their penetration, softening point, dynamic viscosity, master curve, black diagram, Linear Amplitude Sweep (LAS), Multiple Stress Creep Recovery (MSCR), and Fourier Transform Infrared Spectroscopy (FTIR) were obtained. The transparent binders (base and modified) seem to be workable considering their viscosity, and exhibited values between the conventional binder and PMB with respect to rutting resistance, penetration, and softening point. They showed similar behavior to the PMB, demonstrating signs of polymer modification. The addition of TiO₂ seemed to reduce fatigue life, except for the 0.5% content. Nevertheless, its addition in high contents increased the rutting resistance. The TiO₂ modification seems to have little effect on the chemical functional indices. The best percentage of TiO₂ was 0.5%, with respect to fatigue, and 10.0% with respect to permanent deformation.