Sulfatgehalt von Beton - Ermittlung des kritischen Sulfatgehaltes von Beton

The mechanisms of sulphate can vary due to different conditions (ettringite and thaumasite formation). Thaumasite forms at low temperatures and a source of carbonate is needed. It causes damages in the cement matrix, which will lead to a mushy substance. The standards include only volume expansion due to the formation of ettringite or gypsum. But it is not included how fluctuant sulphate concentration should be evaluated. The treshold values of sulphate concentration are assumped under constant conditions. Specimen were made and stored in different sulphate solutions (constant level and fluctuant level) in the laboratory. Other specimen were stored in a waste water sewer to get a practical aspect. Those examinations should give a view, what kind of the influence fluctuant sulphate concentrations have and which sulphate concentration is needed to be harmful