Application of a bio-binder as a rejuvenator for wet processed asphalt shingles in pavement construction

• Bio-binder led to improvement of recycled asphalt shingle (RAS) properties.
• Addition of bio-binder improved low temperature properties of RAS asphalt.
• Ten percent bio-binder alleviated negative impacts of RAS on asphalt.
• Bio-modified RAS showed four degree improvements in cracking temperature.
• Rheological properties of RAS asphalt was improved after bio-modification.

This paper investigates the merits of application of bio-binder to enhance rheological properties of asphalt binder in the presence of wet processed recycled asphalt shingles (RAS). It will further examine the performance and workability of asphalt designed with and without a specified percentage of a bio-binder produced from swine manure and RAS. Bio-binder was introduced to liquid asphalt binder modified with four different percentages of RAS; the high and low temperature properties of each RAS modified binder were then investigated. The study results showed that the addition of bio-binder led to a reduction of viscosity in the RAS modified binder to be closer to that of the virgin binder (without presence of RAS). In addition, it was found that the ductility and fracture energy of the RAS modified asphalt binder was improved significantly when bio-binder was introduced. Overall, the results show that the bio-binder improved the low temperature characteristics of RAS modified asphalt binder; the observed improvement can be attributed to the rejuvenating effect of bio-binder while also improving the blending between the RAS particles and the virgin binder.