It is generally regarded that Gilsonite reduces pavements’ low temperature properties making them susceptible to thermal cracking. Gilsonite melted into hot asphalt will reduce penetration and increase viscosity of the asphalt binder. Gilsonite may also be mixed with aggregate prior to combining with the asphalt binder.

Gilsonite modified asphalt pavements have been particularly successfully in highly stressed traffic areas. Gilsonite, as the majority constituent, has been combined with virgin polymers such as styrene – butadiene – styrene (SBS) and Ethyl Vinyl Acetate (EVA). Gilsonite modified asphalt binders generally do not increase asphalt binder content requirement in pavement mixtures.

Performance grading of asphalt binders and pavement mixtures became a reality with the conclusion of the, “FHWA” 50 million dollar, Strategic Highway Research Program, “SHRP”, in March of 1993.