Micro-encapsulation of asphalt rejuvenators using melamine-formaldehyde

Abstract

Asphalt pavement roads are exposed to traffic loading and natural elements such as rain, sunlight and oxidation, which result in decreasing their relaxation capabilities and the initiation of cracks. Innovative maintenance techniques such as developing microcapsules with rejuvenators have emerged in order to reverse the aging process in asphalt binder. The objectives of this study were to assess the effectiveness of an asphalt rejuvenator to reverse the aging process in asphalt binder and to develop a microencapsulation procedure for the tested asphalt rejuvenator. Properties such as size, shell thickness and morphology of the prepared microcapsules were evaluated by varying the production parameters, i.e. agitation rate, heating temperature, and Ethyl Methyl Acrylate (EMA) concentration. Three binder types were considered in the experimental program, two virgin asphalt binders that were aged in the laboratory and a binder extracted from Reclaimed Asphalt Pavement (RAP). Based on the results of the experimental program, it was concluded that the binder Performance Grade (PG) 70-22 was partially restored at both high and low temperature grades with the use of the rejuvenator. In contrast, the low temperature grade of the binder PG 76-22 and the high temperature grade of the RAP binder were restored with the use of the tested rejuvenator product. Microcapsules containing the rejuvenator were synthesized and a characterization process was conducted based on microcapsule properties such as diameter, shell thickness and morphology of the prepared microcapsules.