Mechanical and Self-Healing Performances of Asphalt Mixtures Containing Recycled Asphalt Materials and Light-Activated Self-Healing Polymer

The objective of this study is to evaluate the efficiency of a new generation of ultraviolet (UV) light–induced self-healing polymers in enhancing the durability of asphalt mixtures and improving their self-healing capabilities. Mixtures were prepared using two different binders, with and without recycled materials, and self-healing polymers. Results showed that the addition of recycled asphalt materials to mixtures prepared with an unmodified binder (PG 67-22) negatively affected healing recovery at room temperature. The self-healing properties of the mixtures were improved by increasing the healing temperature from 25°C to 50°C, which indicates the temperature dependency of the self-healing properties of asphalt mixtures. The addition of 5% self-healing polymers to the control mixture followed by 48 h of UV light exposure resulted in an increase in the self-healing properties of the mixtures prepared with PG 67-22 binder. Semicircular bending (SCB) test results showed that the incorporation of self-healing polymer and 48 h of UV light exposure improved the cracking resistance of the mixture. Loaded-wheel tracking (LWT) test results showed that the addition of the self-healing polymer caused an increase in the rut depth of the samples prepared with the unmodified binder. However, the final rut depth was less than 6 mm, which is an acceptable rutting performance. Thermal stress restrained specimen test results showed that self-healing polymer improved the low-temperature cracking performance of the mix by increasing the fracture load and decreasing the fracture temperature.