Phase Analysis of Portland Cements by Combined Quantitative X-Ray Powder Diffraction and Scanning Electron Microscopy

Published

April 11, 2016

Author(s)

Paul E. Stutzman, Pan Feng, Jeffrey W. Bullard

Abstract

X-ray powder diffraction (XRD) has been used for several decades to identify and measure the mass fractions of various crystalline phases in portland cement. More recently, a combination of scanning electron microscopy with X-ray microanalysis (SEM/XMA) and image processing has been shown to enable the quantitative characterization of microstructural features in these materials. Each technique can furnish some information that is not accessible from the other. For example, SEM/XMA can identify the microstructural location and morphology of calcium sulfate minerals, while only XRD can determine the relative abundance of the different forms of calcium sulfate, such as gypsum, bassanite, and anhydrite. This document describes how XRD and SEM/XMA can be used together to establish and validate the portland cement phase composition and microstructure. Particular emphasis is laid on step-by-step procedures and best practices for XRD specimen preparation, data collection, and intepretation. Similar detail has been given recently for SEM/XMA [Stutzman et al., NIST Tech Note 1877, U.S. Department of Commerce, April 2015]. The methods are demonstrated for three portland cement powders, through which apparent discrepancies between the results of the two methods are identified and procedures are described for resolving them and quantifying uncertainty.

Citation

Journal of Research (NIST JRES) -

Volume

121

NIST Pub Series

Journal of Research (NIST JRES)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/jres.121.004

Keywords

cement, phase composition, X-ray diffraction, scanning electron microscopy, microstructure

Citation

Stutzman, P. , Feng, P. and Bullard, J. (2016), Phase Analysis of Portland Cements by Combined Quantitative X-Ray Powder Diffraction and Scanning Electron Microscopy, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/jres.121.004 (Accessed October 13, 2024)