AASHTO TP 118-15

This method covers determination of the air content and system air metric (SAM) number of freshly mixed concrete from observation of the change in volume of concrete with a sequential change in test pressure.This method is intended for use with concretes and mortars made with aggregates for which the aggregate correction factor can be satisfactorily determined by the technique described in Section 7. It is not applicable to concretes made with light-weight aggregates, air-cooled blastfurnace slag, or other aggregates with high porosity. This test method is also not applicable to nonplastic fresh concrete such as is commonly used in the manufacture of pipe and concrete masonry units.