Estimating the Distribution of Air Voids in Concrete

Authors

  • Beasman L.E. Research Assistant, Dept. of Civil Engineering, Univ. of Maryland, College Park, MD 20742
  • McCuen R.H. Professor, Dept. of Civil Engineering, Univ. of Maryland, College Park, MD 20742

:

https://doi.org/10.9744/ced.13.1.15-20

Keywords:

Concrete, air voids, gradation curves, simulation, linear-traverse method.

Abstract

Chord length measurements are used to estimate the volumetric distribution of air voids within hardened concrete samples. The accuracy of the Linear-Traverse method is questionable because chord lengths do not directly represent the actual volumes of the air voids. Using computer simulation, randomly generated concrete samples were analyzed using the Linear-Traverse method to compute the distribution of air voids, the chord length gradation curve, the chord length-to-traverse ratio, and the air void volume gradation curve. The current chord-length approach significantly underestimated the air void content. A method that estimates that air void gradation curve from the chord length gradation curve is presented. The computer simulation results are supported by a conceptual analysis. To obtain the most accurate estimate of the air void content, computer analyses showed that at least 15 traverse lines should be regularly spaced on the concrete sample.

References

Hover, K.C., Air Content and Unit Weight of Hardened Concrete. Chapter 28 of Significance of Tests and Properties of Concrete and Concrete Making Materials (P. Klieger and J.F. Lemond, eds.), ASTM Special Technical Publication 169c. 296-314, August 1994.

Lord, G.W. and Willis, T.F., Calculation of Air Bubble Size Distribution from Results of Rosiwal Traverse of Aerated Concrete, ASTM Bull., ASTBA, No. 177:56-61, 1950.

ASTM, Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete. ASTM C 457-98, West Conshohocken, PA, 1998.

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Mendenhall, W. and Sincich, T., Statistics for Engineering and the Sciences (3rd ed.), Dellen Publ. Co., San Fran, 1992.

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Published

2011-03-03

How to Cite

L.E., B., & R.H., M. (2011). Estimating the Distribution of Air Voids in Concrete. Civil Engineering Dimension, 13(1), 15-20. https://doi.org/10.9744/ced.13.1.15-20

Issue

Vol. 13 No. 1 (2011): MARCH 2011

Section

Articles

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