Characterization of Asphalt Binder Containing Microcapsules

Abstract

Asphalt pavements are exposed to traffic loading and adverse environmental effects such as rain and oxidation which result in decreasing their relaxation capabilities and the initiation of cracks. Recent research highlights the importance of developing long life pavements. One of the possible ways is to utilize innovative maintenance techniques such as self-healing technologies in order to reverse the aging process in asphalt binder. So as to achieve this goal, self-healing microcapsules seems to be an effective way to autonomously repair the micro-cracks, restore original mechanical properties, then further slow fatigue cracks growth and increase the fatigue life of the pavement. In this study urea formaldehyde (UF) self-healing microcapsule were prepared by in-situ polymerization method. Following the characterization of microcapsules, different amount of microcapsules (6, 8, 9 ,10, 11 and 12%) were added into bitumen. Rheological properties of the samples have been determined by means of Dynamic Shear Rheometer. Ductility test was also employed to characterize the mechanical properties of the bitumen samples. Based on results the produced microcapsules can endure high temperatures, which indicate that these microcapsules can resist the thermal influence of bitumen in application. Besides, bitumen samples involving microcapsules exhibit satisfactory results in terms of complex modulus (G*) and bitumen recovery tests. The recovery value of the modulus increased first and then decreased with the amount of microcapsules. Microcapsules containing rejuvenator will be a promising product to realize the smart pavements.