In this research project, IR spectroscopy in combination with mathematical tools (chemometrics) is going to be evaluated as an analytical method for the characterisation of silica based materials, primarily X-ray amorphous materials, with regard to the reliable determination of the composition of material mixtures with X-ray amorphous materials (e.g. ternary cements with calcined clay and/or recycled concrete fines). In a next step, the findings on the analytical method and evaluation routines developed for cement are going to be evaluated with regard to their transferability to siliceous aggregates for estimating its alkali sensitivity.