Air voids in concrete occur in the process of mixing and placement. When the air is comprised of smaller bubbles, the concrete does not lose much strength and has better workability. The bubbles actually form cushions between aggregates, and a lower water content is the result. Also, the air voids help to protect the concrete from freeze damage. The water tends to expand when it freezes and causes stress to the concrete, which then eases when it thaws.

Air void testing is especially important where frost-related damage to concrete can occur. M&L’s Linear Traverse Machine facilitates the counting of microscopic voids in concrete, and meets or exceeds ASTM C457 certifications.