Penetration grading and viscosity grading are somewhat limited in their ability to fully characterize bitumen binder for use in HMA pavement. Therefore, as part of the Superpave research effort new binder tests and specifications were developed to more accurately and fully characterize bitumen binders for use in HMA pavements. These tests and specifications are specifically designed to address HMA pavement performance parameters such as rutting, fatigue cracking and thermal cracking.
Superpave performance grading (PG) is based on the idea that an HMA bitumen binder’s properties should be related to the conditions under which it is used. For bitumen binders, this involves expected climatic conditions as well as aging considerations. Therefore, the PG system uses a common battery of tests but specifies that a particular bitumen binder must pass these tests at specific temperatures that are dependent upon the specific climatic conditions in the area of use.
Superpave performance grading uses the following bitumen binder tests:
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Rolling Thin Film Oven (RTFO)
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Pressure aging Vessel (PAV)
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Rotational Viscometer (RV)
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Dynamic shear Rheometer (DSR)
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Bending beam Rheometer (BBR)