California Department of Transportation

Performance Graded (PG) Binder

The Performance Graded (PG) system is a method of measuring asphalt binder performance. It was originally developed during Strategic Highway Research Program (SHRP) in the early 1990's. In 2005, California agreed to adopt the PG system for grading asphalts in the state.

The main purpose of classifying and selecting asphalt binders using the PG system is to make certain that the binder has the correct properties for a given environment. PG grading uses various measurements of the binder's flow properties to establish its grade, which is expressed as two numbers. For example, in "PG 64-22," the "64" represents the maximum pavement temperature, in degrees Celsius, for which this binder can be used with low traffic levels. The second number, "-22," signifies the minimum temperature, in degrees Celsius, for which the binder can be used without likelihood of failure.



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