X-ray Diffraction Analysis of Cement (2)

Significance of the Topic

Quantitative phase analysis of cement is critical for controlling its mechanical and chemical performance in construction applications. Accurate determination of clinker phases such as alite, belite, aluminate and ferrite enables manufacturers to predict setting time, strength development and durability. Implementing robust analytical protocols supports quality control, regulatory compliance and product optimization.

Study Objectives and Overview

This application note demonstrates the use of Rietveld refinement for quantitative phase analysis of a cement powder sample. The aim is to illustrate how Siroquant software can deconvolute overlapping X-ray diffraction peaks and deliver precise weight fractions of key clinker minerals. Complementary elemental analysis by X-ray fluorescence (EDX) is also presented to support phase identification.

Methodology and Instrumentation

The cement powder was analyzed on a Shimadzu XRD-6100 diffractometer equipped with a OneSight wide-range high-speed detector. The measurement conditions were:

• Radiation: Cu Kα (30 kV, 50 mA) with Ni filter
• Scan range: 10–80° 2θ, step scan at 10°/min, divergence slit 0.5°
• Sample rotation: 30 rpm

Siroquant software applied the Rietveld refinement method using theoretical peak profiles and least-squares fitting to quantify six crystalline phases. Elemental composition was determined by EDX using the fundamental parameter method, assuming oxide forms.

Main Results and Discussion

Rietveld refinement achieved an excellent fit (χ² = 16.04), even with overlapping alite and belite peaks near 32–34° 2θ. Quantitative phase fractions (wt%) were:

• Alite (C₃S): 72.6
• Belite (C₂S): 12.9
• Ferrite (C₄AF): 7.1
• Aluminate (C₃A): 4.9
• Hemihydrate gypsum: 1.6
• Periclase (MgO): 0.9

EDX confirmed the presence of Ca, Si, Al, Fe, S and Mg, corroborating the phase assignments from XRD. The combined approach enhances confidence in both qualitative and quantitative analyses.

Benefits and Practical Applications

• High-accuracy phase quantification, even with severe peak overlap
• Streamlined QC workflow combining XRD and EDX data
• Reduced reliance on calibration standards for each phase
• Improved traceability and reproducibility in cement production

Future Trends and Potential Use

• Integration of in-line XRD sensors for real-time process monitoring
• Application of machine learning to accelerate pattern fitting and phase prediction
• Extension of Rietveld analysis to supplementary cementitious materials (slag, fly ash)
• Development of automated reporting tools for regulatory audits

Conclusion

This study highlights the effectiveness of Rietveld refinement via Siroquant for quantitative cement phase analysis. When combined with EDX elemental data, it delivers a comprehensive characterization framework that supports rigorous quality control and product development in the cement industry.

Used Instrumentation

• Shimadzu XRD-6100 diffractometer with OneSight detector
• Siroquant Rietveld analysis software (Sietronics Pty. Ltd.)
• EDX accessory for elemental analysis

References

• Shimadzu Application News No. X263: X-ray Diffraction Analysis of Cement (2017)
• Shimadzu Application News No. X247: Fundamental Parameter Method in EDX