Effect of capsule addition and healing temperature on the self-healing potential of asphalt mixtures

Abstract

This paper presents the self-healing results of asphalt mixtures by the action of capsules containing sunflower oil as encapsulated rejuvenator. Three different capsule contents, 0.10, 0.25 and 0.50% by total weight of the mixture, were added to the samples. The mechanical and thermal properties of capsules have been evaluated. In addition, the effect of the capsule addition and the healing temperature on the self-healing properties of asphalt mixtures have been evaluated through three-point bending tests on the cracked asphalt beams with, and without, capsules. The test was implemented by comparing the strength recovery of the broken beams after healing to their original flexural strength. It was proven that the capsules can resist the mixing and compaction processes and break inside the asphalt mixture as a result of applying external mechanical loads, releasing the encapsulated oil. The capsules content in asphalt mixture has a significant influence on the healing level, where a higher capsule content led to obtaining higher healing levels. Likewise, asphalt with, and without, capsules presents an increase of the healing level when the temperature increases. Finally, it was proved that healing temperature has higher influence on the healing levels of the asphalt below 40 °C.