Abstract
Air blowing is combined with high temperature-high shear mixing to produce a high cure asphalt rubber that differs in several important ways from conventional asphalt rubber material. It has excellent grade-span, good settling properties and low high-temperature 135°C (275°F) viscosity, important characteristics for easy use as a binder in dense-graded mixes. These properties are related to curing conditions, rubber mesh and asphalt composition. The grade span is very dependent on asphalt composition and the extent of air oxidation but relatively insensitive to other curing variables and to mesh size. Settling is dependent on the extent of oxidation, original mesh size and the degree of high shear mixing.