Combining Raman Spectroscopy, DFT Calculations, and Atomic Force Microscopy in the Study of Clinker Materials

Area of Science:

• Materials Science
• Solid State Chemistry
• Spectroscopy

Background:

• Portland cement clinker contains essential minerals like alite and belite.
• Distinguishing alite and belite is crucial for understanding cement hydration.
• Their similar phonon bands in Raman spectra pose a significant analytical challenge.

Purpose of the Study:

• To develop a method for differentiating alite and belite in cement clinker.
• To provide novel insights into the vibrational properties of alite and belite.
• To explore the utility of low-frequency Raman spectroscopy for clinker analysis.

Main Methods:

• Combined Raman spectroscopy, Raman mapping, and atomic force microscopy.
• Performed density functional theory calculations for phonon density of states.
• Analyzed Portland cement clinker (217) for spatial and chemical composition.

Main Results:

• Identified alite, belite, portlandite, amorphous calcium carbonate, and gypsum in the clinker.
• Calculated phonon density of states for alite (Ca3SiO5) and belite (Ca2SiO4) for the first time.
• Observed a distinct difference in the lowest phonon frequencies: 27 cm-1 for alite and 102 cm-1 for belite.

Conclusions:

• Low-frequency Raman spectroscopy offers a promising method for distinguishing alite and belite.
• The calculated phonon data provides a basis for experimental identification.
• This research advances the understanding of cement clinker composition and hydration.