Evaluation of Chromate Content in Cement and Fly Ash

Project Number 264

With the 8th regulation regarding the amendment of chemical-legal regulations the marketing of cement and cement containing preparations is forbidden if the content of soluble chrome VI is higher than 2 mg/kg dry weight of the cement in the ready-mixed preparation after water addition. By amending this regulation concrete shall be used chromate-reduced for most applications since 2005, too. However, a test procedure to determine the chromate content of concrete is not defined, yet.

So far the chromate content of cement is determined according to the Technical Regulations for Dangerous Materials (TRGS 613). By this, a cement water suspension is produced, filtered and the chromate content in filtrate is determined. Since August 2004, the European Standard prEN 196-10 regarding the determination of chromate content is available. Unlike the TRGS procedure mortar is mixed and filtrated.

With these examinations it is to be determined whether or not the procedures are also suitable to evaluate the chromate content of fly ash as well as to what extent the results of the two procedures are comparable. Furthermore, it is to be examined which influence has the addition of fly ash on chromate content of a fly ash/cement mixture.

The project is carried out by the Institute for Building Materials at the RWTH Aachen managed by Prof. Brameshuber and is technically supervised by the Working Panel “Power plant by-products”. Project results are to be expected from March 2005.