The objective of this study was to test the hypothesis that hollow-fibers encapsulating a rejuvenator product could improve both self-healing, rejuvenation, and mechanical properties of asphalt mixtures. Hollow-fibers containing a rejuvenating product were synthesized via a wet spinning procedure with sodium-alginate polymer as the encapsulating material. An optimization of the production parameters for the synthesis of fibers was performed to develop fibers suitable for high-temperature and shear stress environment typical of asphalt mixture production. A self-healing experiment was conducted to evaluate the healing/rejuvenation capabilities of sodium-alginate fibers in asphalt mixtures with varying types of binders and recycled materials. Based on the self-healing experiment, a 5% fiber content was determined to be the optimum fiber content to enhance the self-healing ability of asphalt mixtures. In addition, the effect of different fiber contents on binder blends and asphalt mixtures was evaluated by performing the Multiple Stress Creep Recovery (MSCR) and Semi-Circular Bending (SCB) tests. Results of the self-healing experiment showed that the enhancement in the healing recovery depends on the breakage of the fibers. When the fibers break, the rejuvenator is released resulting in softening of the binder. In contrast, when the fibers do not break, they act as a reinforcement for the mix. Loaded Wheel Tester (LWT) test results showed a performance improvement against permanent deformation for asphalt mixtures containing recycled materials with sodium-alginate fibers compared to conventional asphalt mixtures. Furthermore, SCB test results showed that the addition of sodium-alginate fibers enhanced the fracture properties of asphalt mixtures with Recycled Asphalt Shingle (RAS) at intermediate temperatures. Moreover, the addition of fibers in mixtures with recycled materials resulted in an improved performance against low-temperature cracking as the mixtures resisted higher stresses before failure.
Hassan, M. (2018). Development of a Self-healing and Rejuvenating Mechanisms for Asphalt Mixtures Containing Recycled Asphalt Shingle. Retrieved from https://repository.lsu.edu/transet_pubs/5