The influence of ferrous sulphate on Portland clinker hydration

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The issue of hexavalent chromium toxicity in Portland cement hydration is very topical at present. It takes a lot of effort to obtain cements containing Cr(VI) less than 2 ppm. The primary goal of this thesis was to explore the influence of a substance which could reduce hexavalent chromium and at the same time retard the hydration of Portland clinker. It is a very important fact because Portland clinker after mixing with water starts to harden immediately. The substance, which has these properties, is ferrous sulphate. The reduction ability was determined by UV/VIS method. The concentration of hexavalent chromium leaching is significantly lower with the addition of a very small amount of ferrous salt. The calorimetric measure showed that ferrous sulphate can be used as a retarder substance in the hydration of Portland clinker. This fact involves the presence of sulphate anions. The next measurements performed were the strength tests. Their results showed the decrease in the strength when compared with the strength of Portland cement. The hydration products of Portland clinker after the gypsum replacement by ferrous sulphate were also investigated. The goal of this study was to identify the hydration products which result in the retard hydration. The presence of these products was determined by XRD method and Raman microscopy.

portland clinker, ferrous sulphate

HAJDÚCHOVÁ, M.; ŠOUKAL, F.

6. 12. 2013

Vysoké učení technické v Brně, Fakulta chemická, Purkyňova 464/118, 612 00 Brno

978-80-214-4822-3

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