A reply to a discussion by D. Bonen of the paper “quantitative backscattered electron analysis of cement paste”

✍ Scribed by Hong Zhao; David Darwin

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 276 KB
• Volume: 23
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(93)90028-8

✦ Synopsis

The authors appreciate Bonen's discussion. He has raised a number of useful points that should be addressed.

At the outset, it appears that Bonen has concluded that the preset gray levels used to identify phases within cement paste were selected based on "absolute" backscatter coefficients. This was not the procedure used in the study (1, 2), and the authors are pleased to correct this misunderstanding. The background information presented in the paper describing the application of the technique was aimed at establishing the theoretical justification for quantitative backscattered electron imaging. Knowledge of the backscatter coefficients is useful in establishing the relative intensity of the signals and determining if the signals produced by individual elements, or phases within cement paste, are sufficiently different to allow the materials to be distinguished from each other. If the contrast between individual phases is adequate, an imaging strategy can be developed to take advantage of that contrast. Thus, relative, not absolute, differences in gray level are used to identify specific phases within the imaged material. The techniques presented in the paper allow this to be done on a reproducible basis by allowing calibration of the instrumentation.