- Author
-
Stutzman, P. E.
- Title
- Quantitative X-Ray Powder Diffraction Methods for Clinker and Cement.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
-
NISTIR 5403,
May 1994,
18 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
building technology
|
cements
|
clinker
|
phase abundance
|
x ray powder diffraction
|
sample preparation
- Abstract
- Performance of concrete is influenced by the portland cement phase composition. Phase abundance determination has traditionally been accomplished using two different methods; optical microscopy, and a Bogue calculation based on a chemical analysis. However, optical microscopy is an arduous method for routine clinker evaluation. Phase compositions by Bogue calculation are often in error because of necessary assumptions of the true compositions of the cement phases. X-ray powder diffraction is a direct, bulk analytical method for phase analysis of fine-grained materials including clinker and cements. Each phase produces a unique diffraction pattern independently of the others with each pattern intensity being proportional to phase concentration. Difficulties in X-ray powder diffraction analysis include correction for sample absorption, selection of reference standards, and determination of individual pattern intensity. These problems are minimized by use of an internal standard, profile fitting, and careful reference standard selection. The availability of computers has revitalized interest in quantitative powder diffraction analysis by facilitating profile fitting for diffraction peak intensity measurement and whole pattern-fitting methods where the entire diffraction pattern, compared to discrete peaks, is used in the analysis.