ABSTRACT
Binder is a general description for the adhesive or glue that is used in asphalt pavements. These liquid binders can be defined as tars and asphalt binders. Asphalt binders are either petroleum derived or naturally occurring. The American Society for Testing and Materials (ASTM) defines bitumen as a class of black or dark colored (solid, semisolid, or viscous) cementitious substances, natural or manufactured, composed principally of high molecular weight hydrocarbons of which asphalt, tars, pitches and asphaltite are typical (ASTM 2001b). The asphalt binder is what gives an asphalt pavement its flexibility, binds the aggregate together, and gives waterproofing properties to the pavement. In North America, the binder is generally known as asphalt cement while in Europe it is known as “bitumen.” Binder, or more specifically, asphalt binder has been developed in more recent terminology under the auspices of the United States Strategic Highway Research Program (SHRP) to include modified asphalt cements, unmodified asphalt cements, asphalt emulsions, and asphalt cutbacks.
