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Kenneth A. Snyder
National Institute of Standards and Technology
Building Materials Division
Gaithersburg, MD 20899
Air void spacing equations have been proposed in the literature by a number of authors: Powers; Philleo; Attiogbe; and Pleau and Pigeon. Each proposed spacing equation attempts to characterize the true "spacing" of entrained air voids in concrete. While efforts have been made to correlate these spacing equation calculations to freeze-thaw performance, no test has been performed to assess the geometrical accuracy of these spacing equations. Herein is a computerized accuracy test of these proposed spacing equations. A computer model of air void systems is used, and various "spacings" are measured in the model system. The results of these measurements are then compared to the appropriate spacing equation prediction, along with equations developed by Lu and Torquato.