Doctor of Philosophy (PhD)
Engineering Science / CMP
A new generation of Ultraviolet (UV) light-induced self-healing polymers was introduced for the asphalt pavement application with the aim to enhance pavements durability while increasing its service life. The developed self-healing polymer was mixed with asphalt binder using two different methods, passive and reactive. For the passive method, the cured self-healing polymer was ground to smaller particle size and then it was mixed with asphalt binder using a high shear stirrer and at a high temperature. For the reactive method, self-healing polyurethane pre-polymer was added to the asphalt binder at a lower temperature and lower shear rate compare to the passive method. Prepared modified binders, were tested using multiple chemical tests, fundamental rheological tests, self-healing tests, and mechanical tests.
For passive method, rheological test results showed that the addition of recycled materials led to an increase in the stiffness of the binder, while the polymer did not have a significant effect. The SCB test results showed that the addition of recycled asphalt materials negatively affected the cracking performance of mixtures. However, incorporation of self-healing polymer with UV light exposure improved the cracking resistance. The LWT test results showed that the addition of the self-healing polymer led to an increase in the rut depth of the samples. The addition of self-healing polymer demonstrated improvement in self-healing properties of mixtures prepared with unmodified binder. In conclusion, when the passive method was used for modification, the desired cross-linked network between the self-healing polymer and asphalt binder did not form. Furthermore, phase separation was observed for self-healing polymer modified binder blends.
In the reactive modification method, a three-dimensional network between self-healing material, polyurethane, and asphalt binder was confirmed using FTIR testing. Rheological test results demonstrated an increase in the high-temperature grading while no significant effect was observed on low-temperature grade. LWT results presented improved rutting resistance. Furthermore, SCB results showed an improvement in the cracking resistance with 5% polymer, however, the Jc value was decreased with an increase in the self-healing polymer percentage. Finally, asphalt mixture with 10% self-healing polymer and continuous exposure to UV light presented the highest crack healing rate.
Shirzad, Sharareh, "Effect of Light Activated Self-Healing Polymers on the Performance of Asphalt Pavement Containing Recycled Asphalt Materials (RAP/RAS)" (2019). LSU Doctoral Dissertations. 5048.