Characterization of principal clinker minerals by FT-Raman microspectroscopy

Abstract Commercial and synthetic clinker minerals have been analyzed by Fourier Transform (FT) Raman microspectroscopy. The spectra of synthetic polymorphs of C 3 S and β C 2 S are compared to their counterparts in commercial clinker. Identification of the calcium silicate phases by FT Raman microscopy conforms with XRD diffractograms. C 3 S is easily distinguishable from C 2 S. The main band of the synthetic C 3 S polymorphs correspond to the out-of-plane Si-O bending ν 4 , and it is shifted to higher energy for the commercial C 3 S. The main band for the C 2 S minerals corresponds to the asymmetric Si-O stretching ν 3 . However, the reported spectra differ from other literature results designating the ν 1 SiO 4 vibration as the predominant lines characterizing calcium silicates. The analyses for synthetic C 3 A polymorphs and C 4 AF conform with the published data.