X-ray photoelectron spectroscopy of the cement clinker phases tricalcium silicate and β-dicalcium silicate

We have used X-ray photoelectron spectroscopy (XPS) to investigate both tricalcium silicate (Ca3SiO5, C3S) and β-dicalcium silicate (Ca2SiO4, β-C2S), the principal components of cement clinkers. In addition to showing how the two phases may be characterised and differentiated, we show how the sensitivity of these phases to atmospheric carbon dioxide and moisture may, as a result of improper sample preparation, lead to erroneous results. The observed alteration processes of the clinker minerals shed light upon the aging process of cement clinker during storage.