Standard Method of Test for Detecting the Presence of Phosphorous in Asphalt Binder

Published by	Publication Date	Number of Pages
AASHTO	2009	4

Category: AASHTO

Description

AASHTO TP 78 – Standard Method of Test for Detecting the Presence of Phosphorous in Asphalt Binder

This qualitative test method can be used to identify the presence of polyphosphoric acid (PPA) in asphalt binder or residue. If PPA is present in the binder, a blue color is developed in approximately five minutes. The test method is not quantitative, but it can detect PPA at concentrations as low as 0.1 percent. The test method can only determine the presence of phosphorus. It is not specific for the presence of PPA. A positive test result assumes that the phosphorus is from PPA. Any additive that contains phosphorus will give a false positive for the presence of PPA.