Field and laboratory validation of the sequential air method

Abstract

This work compares the sequential air method (SAM) and the results from the hardened air-void analysis (ASTM C 457) for 488 different concrete mixtures from the lab and field. The results show that there is a wide variation of air contents that correlate with a Spacing Factor of 200 μm. These results show the inadequacy of using air content to decide the quality air void system of the concrete. In fact, 25% of the field data was shown to have a Spacing Factor higher than the recommended values. The results from the SAM, Spacing Factor, and volume of fine air voids (chords less than 300 μm) exhibited good agreement for both the laboratory and field data. Since the SAM can be used to test concrete before it sets and it can give important insight into the bubble size and spacing, this makes it a valuable tool to design and evaluate the air void system of fresh concrete and provide insight into the air void system in the hardened concrete.