WSDOT currently uses the Superpave (Gyratory) mix design method, but historically it used the Hveem method. Like the Marshall and Superpave methods, the Hveem method has been proven to produce quality HMA from which long-lasting pavements can be constructed. This section briefly discusses the Hveem mix design method, but this design method has largely been displaced by the Superpave (Gyratory) mix design method and has no current application in Washington State or elsewhere in the USA.
HMA consists of two basic ingredients: aggregate and asphalt binder. HMA mix design is the process of determining what aggregate to use, what asphalt binder to use and what the optimum combination of these two ingredients ought to be. There are several different methods used to go about this process, of which the Superpave, Marshall and Hveem methods are the most common. The mix design fundamentals discussed here are applicable to all mix design methods.
WSDOT uses the Superpave mix design method (also commonly called the Gyratory mix design method. Like the Hveem and Marshall methods, the Superpave method has been proven to produce quality HMA from which long-lasting pavements can be constructed. This section briefly discusses the Superpave mix design method.