AAPT symposium: Alternative binders for the production of bituminous materials

The presentation began by discussing the need for alternative binders as a result of increasing asphalt demand, prices, and coking technology. The motivation for alternative binders is to: • enhance binder properties; • reduce dependence on crude oil; • improve the use of underutilized resources to supplement petroleum-based asphalt; • produce more environmentally friendly binders (reduced VOC); and • produce colored asphalt. A review of the research that has been conducted within the past ten years on alternative binders (bio-binders) indicates the following. • The physio-chemical properties of the bio-binders can vary significantly based on the feedstock and processing methods. • Bio-binders derived from lignocellulosic bio-mass have higher viscosity range than biobinders derived from bio-mass with high lipid content. • Bio-binders show significantly lower temperature susceptibility than petroleum-based binders, regardless of feedstock source. • The temperature range for viscous behavior is usually lower for bio-binders than petroleum-based (bitumen) binders. • The high temperature performance grade for bio-binders is typically close to those of bitumen binders. • The low temperature performance grade could vary significantly from bituminous binders depending on the feedstock type and processing method. • Susceptibility of bio-binder to U.V. and oxidative aging varies based on their feedstock source and processing methods. The storage stability of bio-binders could be improved if lighter compounds (aldehydes and ketones) are removed. The presentation concluded with questions yet to be addressed with bio-binders.