Phase analysis and hydration behavior of fine and coarse particle fractions contained in a commercial Portland cement

Abstract

A fine (< 3.5 µm) and a coarse (11 − 63 µm) particle fraction was separated from a commercial OPC and their composition, hydration behavior and impact on engineering properties were extensively studied. The fine fraction showed decreased alite and C₃A (cubic), increased calcium sulfates and limestone contents, whereas C₂S, C₃A (orthorhombic) and C₄AF were mostly unchanged. The phase distribution of the fractions differs to prior literature what has been evidenced using more sophisticated analytical methods like Q-XRD including Rietveld refinement combined with e.g. salicylic acid extraction. The fine fraction produces particularly high early strength through rapid C-S-H and ettringite formation while the coarse fraction contributes mainly to the final strength by C-S-H formation only. The results clearly illustrate the strong impact of the fine particle fraction on the early engineering properties of bulk cement sample, whereas the coarse particle fraction contributes more to final strength.

Keywords:

• Portland cement
• Rietveld refinement
• cement analysis
• fine particle fraction
• coarse particle fraction
• hydration behavior

Acknowledgements

The authors greatly acknowledge the financial support by the German Research Foundation (DFG) within the frame of the SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials”. Moreover, HeidelbergCement is thanked for providing the cement sample.

Additional information

Funding

This work was supported by the German Research Foundation (DFG) under grant [project number: 387082770]