Quantitative Betrachtung der Sulfatdeposition bei Sichtmauerwerksbauten / Fair-faced brick masonry - Estimation of the deposition of sulphates

Deterioration of the surface layer of brick masonry' facades is often due to accumulation of gypsum. While the source of the sulphates is the wet and dry deposition of SO,, the main supplier of the Calcium are the joints. The enrichment of salts may lead to damages within in the brick due to crystallisation pressures and the mechanical properties of the joints will suffer from the reduction of binder. Furthermore. the accumulation of gypsum will cause severe changes in the drying behaviour of the building material, which will enhance the microbiological colo nisation and induce later damages due to frost action in special cases.