This study presents an optimised analytical procedure for quantitative trace element analysis of belite crystals in hardened cement bonded materials by electron microprobe and its application. Within this project, trace element concentrations in belite crystals of 22 cement bonded materials were determined. In each sample 7 to 14 belite crystals were analysed to determine the concentrations of the elements Ca, Si (matrix elements), Na, Al, K, Ti, Fe, Mg, P, S, Zn, Sr, Pb, V, Cr, Mn, Ni, and Ba (potential trace elements) with a beam current of 15 and 120 nA and a total counting time of 30 minutes.

Trace elements show total concentrations between 4 and 8 wt% of the oxides. Na, Al, K, Ti, Fe, Mg, S and Sr show high concentrations generally above 1000 ppm. P, Mn and Ba are generally within the 100–500 ppm level while Zn, V and Cr are below 100 ppm. Pb and Ni are below the limits of detection. The results show that trace element distribution of belite in each of the used cement materials has its characteristic trend. This opens up interesting perspectives for testing institutions, e.g. to evaluate, whether two cement bonded specimens are of the same origin or not.

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