ACI Concrete Strength Testing Technician Practice Test

Measuring air content in freshly mixed concrete is done using the pressure method outlined in ASTM C231. This standard describes how to use an air meter to determine the percentage of air voids in the concrete by applying a known pressure to the sample and calculating the air content from the pressure-volume relationship. It’s the widely adopted approach for field and lab quality control because it provides quick, direct measurements of air content in fresh concrete.

The other standards mentioned serve different purposes. ASTM C150 specifies cement properties, ASTM C31 covers making and curing concrete test specimens, and ASTM C330 relates to structural lightweight concrete. None of these define the procedure for measuring air content like ASTM C231 does.