| With depleting natural resources, fluctuating costs, and increasing waste management concerns, the increased use of aged asphalt materials in new pavement construction is vital in ensuring the continuation of a reliable transportation asphalt infrastructure for society. However, research has shown that increased usage of aged asphalt such as recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) can adversely affect the performance in new pavement construction, particularly low--temperature performance. Therefore, the use of rejuvenating agents could increase the use of aged asphalt in new construction while not adversely affecting pavement performance and pavement life. To increase sustainability by using renewable resources, Bio-Binder (BB), a bio-oil derived from swine manure, was selected to determine if rejuvenating effects could be observed. This study consisted of fabricating and testing asphalt mixtures with 15% and 45% RAP and with 5% and 10% BB at low temperatures, and testing artificially aged binder at high, intermediate, and low temperatures. The surface topography was also studied using atomic force microscopy (AFM), and a statistical analysis was performed to determine if the microstructural surface features could be linked to binder rheology. The results of these experiments showed that rejuvenation effects were observed at both the mixture and binder level that yielded performance close to or even better than that of the unaged material. AFM results showed a change in microstructural surface features with aging and a shift back to the unaged features with increased BB percentage. Statistical analysis showed that the maximum length of the bee structures has a moderating effect of viscosity on stiffness. |
