- Author
- Natesaiyer, K. | Simon, M. | Snyder, K. A.
- Title
- Mean Spacing of Air Voids in Hardened Concrete.
- Coporate
- USG Corp., Libertyville, IL Federal Highway Administration, McLean, VA National Institute of Standards and Technology, Gaithersburg, MD
- Journal
- ACI Materials Journal, Vol. 91, No. 1, 123-127, January/February 1994
- Keywords
- spacing | concretes | equations
- Abstract
- The author has derived an expression for the mean spacing of air voids in hardened concrete, and states that this expres-sion yields a better estimate of tbe actual spacing of the air voids in hardened concrete than the standard spacing actor." We feel there are several points reganzling this new expression that quite Clarification and warrant dkcussion. First, it is not clearly stated in the paper what the expres-sion for mean spacing represents physically. Throughout the paper, the author uses several phrases as synonyms for mean spacing, such as "average half distance between air void walls," "average value of the maximum distance that water must travel to reach an air void," "mean thickness of paste envelopes around the air voids," and "one-half the mean clear spacing between adjacent voids." None of these are necessarily equivalent. Therefore, it is not clear whether the authors intention was to derive an expression for the mean distance, or half-distance, between air voids, or for the mean, or maximum, distance between any point in the paste and the nearest air void.