Substanzerhaltung historischer Mauerwerksbauten, Quantifizierung der Wirkung von Luftverunreinigungen auf Baustoffe, insbesondere auf Aussenputz

The effect of the air pollutants sulfur dioxide, nitrate and chloride on renderings has been studied at historical buildings and at building materials. While the effect of nitrate and chloride clearly depends on the relative orientation of the walls to the emission source, the SO_2 effect is independent of the orientation. In connection with sun irradiation, temperature changes and dewfall the pollutants cause changes in the pore system: the portion of capillary active pores (2-100 #mu#m pore diameter) largely increases, and as a result the vapour diffusion resistance is distinctly decreased. The general behaviour of masonry building towards moisture diffusion depends on the pore volume and the pore size distribution as well as on the grain size distribution of mortar additives. (WEN)Available from TIB Hannover: RN 8908(94-094) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman