Laboratory Testing of Self-Healing Fibers in Asphalt Mixtures Prepared with Recycled Materials

Self-healing products such as hollow fibers filled with a recycling agent present an emerging technology that would enhance an asphalt mixture’s resistance to cracking damage in the long term. The objective of this study was to evaluate the healing efficiency of sodium-alginate fibers containing a recycling agent using asphalt concrete beam specimens. A self-healing experiment was designed and conducted to monitor strength recovery in the damaged specimens using a 3-point bending test during a 6-day healing period under two different environmental curing conditions. In addition, the effects of adding the hollow fibers on the mechanical properties of asphalt mixtures were evaluated by conducting a series of laboratory tests to evaluate the performance against common distress such as permanent deformation, intermediate cracking, and low-temperature cracking. Results of the self-healing experiment test results showed that the addition of sodium-alginate fibers improved the strength recovery of mixtures prepared with unmodified binder. The increase in temperature from 25°C to 50°C during the healing period also resulted in higher strength recovery percentages in all the evaluated mixtures. Furthermore, semi-circular bending test results showed that the addition of fibers enhanced the mechanical properties against fracture at intermediate temperature of mixtures containing recycled asphalt materials.