Study of aggregate samples with iron sulfides through micro X-ray fluorescence (μXRF) and X-ray photoelectron spectroscopy (XPS)

Analyses of samples with iron sulfides are performed through micro X-ray fluorescence (mu XRF) and X-ray photoelectron spectroscopy (XPS) in order to evaluate the possibilities offered by those techniques in the characterisation and quantification of iron sulfides contained in the aggregates used in concretes pursuant to the American standard ASTM_C_294-05 (ASTM C 294-05 standard descriptive nomenclature for constituents of concrete aggregates, 2005) and European standard EN_12620:2008 (EN 12620:2008. Aggregates for concrete, 2008) protocols. In the case of the American norm, which does not draw a distinction between the different sulfide species, mu XRF may be sufficient if combined S and Fe mappings are used. XPS meets the demands both of the American and the European norms, which permits to distinguish sulfide types, and 0.1 % by mass of S can actually be detected if the aggregates contain pyrrhotite.