Reference: S.T. Erdogan, P.N. Quiroga, D.W. Fowler, H.A. Saleh, R.A. Livingston, E.J. Garboczi, P.M. Ketcham, J. G. Hagedorn, and S.G. Satterfield, submitted to Cement and Concrete Research (2005).

Three-dimensional shape analysis of coarse aggregates: Methodology and preliminary results on several different coarse aggregates and reference rocks

S.T. Erdogan, P.N. Quiroga, and D.W. Fowler
Department of Civil Engineering
University of Texas
Austin, TX 78712 USA

The shape of aggregates used in concrete is an important parameter that helps determine many concrete properties. The mathematical technique of spherical harmonic analysis was recently demonstrated to be able to effectively analyze three-dimensional information on aggregate shape. This paper discusses the sample preparation and image analysis techniques necessary for obtaining an aggregate particle image in 3-D, using x-ray computed tomography, which is suitable for spherical harmonic analysis. The shapes of three reference rocks are analyzed for uncertainty determination via direct comparison to the geometry of their reconstructed images. A Virtual Reality Modeling Language technique is demonstrated that can give quick and accurate 3-D views of aggregates. Shape data on several different kinds of coarse aggregates are compared and used to illustrate potential mathematical shape analyses made possible by the spherical harmonic information.

Keywords: B. Image and shape analysis; D. Aggregate; E. Composite; Modeling

• Introduction
• Mathematical background
• Sample preparation, image analysis, and VRML image production
• Reference rocks
• Four kinds of real aggregates: Image acquisition and sieve analysis
• Four kinds of real aggregates: Numerical shape analysis
• Summary and future work
• Acknowledgements
• References

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