Evaluation of conventional technical properties and self-healing ability of bitumen-based sealants containing sunflower-oil microcapsules for pavement cracks

Abstract

The bitumen-based sealants have been widely used to repair the pavement cracks, but the pavements always crack again at the healing patches due to the insufficient durability of sealants. In order to improve the technical properties and self-healing ability of bitumen-based sealants, the microcapsule technology was applied, and the sunflower-oil microcapsules were prepared by in-situ polymerization method. The sunflower-oil microcapsules were then added into the bitumen-based sealants, and the dispersion characteristic was observed by fluorescence microscopy, Then the cone penetration, softening point, resilience recovery, fluidity, tensile property sealants, self-healing ability as well as the two-stage loading dynamic shear rheological (DSR) tests were conducted to study conventional technical properties and the self-healing ability of bitumen-based sealants containing microcapsules with different contents. The results show that microcapsules could be well dispersed in the sealants state without agglomeration, and the conventional properties of bitumen-based sealants containing microcapsules meet the technical requirements, except for low-temperature tensile properties of the sealant with 4% microcapsules. The cone penetration and fluidity decrease with increasing microcapsule content, while the softening point and resilience recovery increase. Compared with the original sealants, the self-healing ability of the sealants with microcapsules was superiority obviously, and the optimum content of microcapsules was recommended as 2%, which was also suitable for the aged sealants. And the sunflower-oil microcapsules can improve the repeated self-healing ability and fatigue life of the sealants at the temperature as low as −20 °C.