Development of a new apparatus for in-situ determination of air void characteristics, particularly the distribution of entrained air system in freshly-mixed concrete during mixing, pouring, and placement is described. Air content is measured by a fiber optic probe. Reflected light intensities determine the distribution of air bubbles in fresh concrete. The system has the ability to rapidly sample air content at different locations or depths in plastic concrete improving existing quality control procedures. Air content measurements are direct, and not influenced by the type and amount of aggregates, cementitious components, and admixtures. © 1990.
