1. Federal Institute for Materials Research and Testing, Division 1.1 Inorganic Trace Analysis, Richard-Willstäter-Straße 11, 12489 Berlin, Germany
2. Federal Institute for Materials Research and Testing, Division 7.4 Technology of Construction Materials, Unter den Eichen 87, 12205 Berlin, Germany
3. Technische Universität Berlin, Department of Civil Engineering, Building Materials and Construction Chemistry, Gustav-Meyer-Allee 25, 13355 Berlin, Germany