ASTM C231/C231M-17a PDF Download

The ASTM C231/C231M-17a standard provides guidelines for determining the air content in freshly mixed concrete. The test method aims to exclude any trapped air within aggregate particles. It is applicable when working with concrete made from dense aggregate particles and requires the determination of the aggregate correction factor.

This test method is one of three available for determining air content, along with Test Method C138/C138M and C173/C173M. The pressure procedure outlined in this standard yields similar results to the other two methods when working with concrete made from dense aggregates.

It is important to note that the air content in hardened concrete may differ from that determined by this test method. Several factors can influence the air content in hardened concrete, including the consolidation effort applied, stability of air bubbles, environmental exposure, and the timing at which the air content is determined during the delivery, placement, and consolidation processes.

The standard also emphasizes that it is not applicable to concretes made with lightweight aggregates, air-cooled blast-furnace slag, aggregates of high porosity, or nonplastic concrete used in pipe and concrete masonry units. Additionally, the standard includes explanatory notes and footnotes that do not constitute requirements of the standard.