The behaviour of natural calcium sulphates or FGD gypsum in combination with clinker could not easily be transferred to RC gypsum. Due to a lack of knowledge about the influence of other components in RC gypsum on cement, mortar and concrete properties, RC gypsum has only been used to a very limited extent, if at all, even though this secondary source of sulphate is generally considered to be very suitable.
Basic knowledge about the composition of RC gypsum and its behaviour during the grinding process as well as its solubility was determined. The suitability of RC gypsum for controlling the setting and hardening of cement and its influence on strength development and also the effectiveness of concrete admixtures was also determined. Requirements for RC gypsum with regard to its use as a sulphate carrier for cement production and any measures required to achieve these were defined.
Importance for SMEs
Small and medium-sized enterprises (SMEs) often lacked the necessary scientific and technical equipment and personnel for the necessary investigations. This was therefore a typical IGF task, the results of which primarily benefit SMEs in the German cement industry. The results can also be used by SMEs in the recycling industry to optimise processing and RC gypsum quality. This maintains and promotes the competitiveness of SMEs.
