Bio-Modified Rubber: A Sustainable Alternative for Use in Asphalt Pavements

This paper investigates the feasibility of application of scrap tire and swine manure to produce a sustainable alternative for bituminous asphalt used in pavement construction. Bio-binder is produced from swine manure using thermo-chemical conversion processes. Bio-binder is then blended with crumb rubber and asphalt binder to produce bio-modified rubber (BMR) asphalt. In addition to offering a solution for the management of swine manure and scrap tire, BMR can be a renewable alternative for petroleum-based binder used in pavement construction. To study merit of application of BMR in asphalt industry, this paper compares the rheological properties of BMR with a crumb rubber modified binder (CRM) commonly being used in the U.S. It was found that BMR has comparable properties with CRM. In addition, introduction of bio-binder to CRM asphalt binder found to be beneficial because bio-binder reduces asphalt viscosity allowing for lower mixing and compaction temperature and alleviate crumb rubber's stiffening effect.