The quality of reinforced concrete elements depends not only on the average quality of the concrete, but much more on the dispersion of weak areas. In conventional concrete the heterogeneity of the concrete cover is mainly influenced by the compaction process. Among other advantages this fact has first lead Japanese researchers to develop self-compacting concrete. In the meantime this promising material is also applied in Europe and in particular in Sweden and France. In Switzerland so far few tests have been run only. In order to provide a solid basis for the safe application of this new technology the properties of self-compacting concrete are to be optimized.