Addressing Durability of Asphalt Concrete by Self-healing Mechanism

Every year a huge amount of energy and economic resources are employed in preservation and renovation of the existing pavements. In the last years, rejuvenators are being used in road maintenance works by restoring the original properties of the aged pavement. The main problem is that once the rejuvenator is spread on the road surface to be effective it must penetrate into the pavement not only in the first centimeters. An innovation procedure to solve this problem is the addition of encapsulated rejuvenators into the asphalt mixes. Once the rejuvenator is released, it will be in contact with the bitumen around restoring the original properties of the binder and increasing the self-healing rate by closing the cracks or limiting its growth. In the present work two encapsulation methods developed by the authors are described. The first one, porous aggregates with the rejuvenator embedded were prepared; the second one polymeric shell microcapsules containing the rejuvenator were synthesized. After preparation and encapsulation of the healing agent, the capsules were embedded into the bituminous matrix. Finally, the autonomous repairing capability was validated through a variety of comparative laboratory tests. Results from this study indicate that the self-healing chemistry developed has a high potential for its use in asphalt pavements by increasing its durability.