Trade Journals for the Concrete Industry

Under the European Directive 2003/53/EC, since January 2005 only cement containing less than 2 ppm of water-soluble chromate may be sold and used. Normally, adherence to the upper limit for chromate is guaranteed during cement manufacture by the specific addition of a chromate reducer. The quantitatively most frequently employed chromate reducing compound is iron(II) sulphate. This paper summarises research results and experience which were acquired both in the run up to the changeover and during just under two years of practical application. This comprises an examination of the effects of iron(II) sulphate on the reaction properties of cement and the associated characteristics of fresh and hardened concrete.