Volume 22, Issue 6 (November 1994)
Comparison of Asphalt Contents Measured with the Nuclear Gage and Extraction Methods
Asphalt content is a critical property for controlling the quality of hot mix asphalt. Currently two procedures, solvent extraction (ASTM D 2172, Test Method for Quantitative Extraction of Bitumen from Bituminous Paving Mixtures) and nuclear gage (ASTM D 4125, Test Method for Asphalt Content of Bituminous Mixtures by the Nuclear Method), are used to compare asphalt content. This paper uses field data and data from four laboratory round robin testings to compare asphalt contents measured by the two methods. Asphalt content measurements made by nuclear gages are higher, more accurate, and more precise than asphalt content measurements made by the centrifuge solvent extraction method.