Bitumen (Binder) Content of a Mix

A sample of bituminous mix is subjected to extraction (using a solvent in a centrifuge or reflux extractor) to separate the bitumen binder from the mineral aggregate. The weight of extracted binder, expressed as a percentage of the total mix, is the binder content.

This is a key production quality-control check — too little binder produces a mix prone to raveling and cracking, while too much makes the pavement prone to rutting and bleeding.