Dauerhaftigkeit von Betonkonstruktionen

The 8th Munich Building Materials Seminar (Fig. 1) organized by the cbm Center for Building Materials at the Technical University of Munich took place successfully on October 10, 2008 in honor of and as a farewell to Univ.-Prof. Dr.-Ing. Dr. Ing. E.h. Peter Schießl (Fig. 2). About 250 experts met in Munich in order to gather information about the core subject of the scientific achievement of Peter Schießl – the durability of concrete structures. The speeches, which were exclusively delivered by his former assistants as requested by Prof. Schießl (Fig. 3), were subdivided into the fields of mechanisms, determination of life cycles and esthetics. Attention was given to the aspects of microstructure, concrete mixture, corrosion of steel, repair principles, life cycle determination of concrete structures, and – as an example for the problem of modeling – freeze-thaw resistance.

After the welcome speech by Prof. Dr.-Ing. Detlef Heinz, Prof. Dr. rer. nat. Birgit Meng presented in detail the correlation of microstructure and durability of cement-bound construction materials. Afterwards, Dr.-Ing. Udo Wiens outlined the influence of the concrete mixture on durability. His speech focused on the question of how the resistance of concrete changes against the penetration of chlorides and sulfates through the addition of fly ash and what are the reasons for these effects.

In his speech about the subject “Corrosion on steel in concrete – mechanisms and influencing parameters”, Prof. Dr.-Ing. ­Wolfgang Breit gave a well-founded introduction and described how the respective partial process decisive for corrosion (anodic iron dissolution, cathodic oxygen reduction or an electrolytic process) may be identified. This allows a correct evaluation of the numerous influencing parameters ­(water-cement ratio, contents of slag sand and/or ­silicate dust) on the corrosion rate.

In his speech Dr.-Ing. Romain Weydert explained the mechanisms of action and the experience of repair principles in building practice. Afterwards, Prof. Dr.-Ing. Christoph Gehlen gave a very good review about the life cycle management of concrete structures. Dipl.-Ing. Dirk Lowke and Dipl.-Ing. ­Christian Brandes gave a comprehensive insight into the possibilities of modeling a deterioration process of concrete in case of freeze-thaw deterioration with de-icing salt.

In the third series of speeches two contributions focused on esthetics as being an important usage property nowadays. Dipl.-Ing. Felix Mayer, ­reported on mechanisms, influencing factors, and avoidance strategies in case of iron stains on concrete surfaces caused by steel formwork, before Dipl.-Ing. Dirk Lowke presented the project of Dipl.-Ing. Doris Stehlein about the causes and possibilities of avoiding discoloration on exposed concrete surfaces.

The seminar day was concluded with the closing words of Prof. Dr.-Ing. Christoph Gehlen, who has been acting as successor of Prof. Schießl at the Technical University of ­Munich since the
1st October 2008. The really successful seminar gave a quite comprehensive overview about almost any aspect relevant to the sustainability of concrete structures. The speakers incorporated the works they carried out in collaboration with Peter Schießl in their speeches partly very humorously and with funny images and thanked him for the excellent cooperation. A conference transcript, combining the most interesting contributions of the speakers, is in preparation.