Kapillares Eindringen von Wasser und Salzlösungen in Beton / Penetration of Water and Salt Solutions into Concrete by Capillary Suction

Capillary suction plays a dominant role in the ingress of chlorides and therefore in the durability of concrete. The capillary absorption of fluids into concrete is analysed in terms of a simple capillary-model. With the help of this model and under given conditions, the water and chloride transport by capillary suction can be described in a realistic way. The fundamental influences of different parameters such as porosity, pore size distribution, moisture content and interaction between fluid and concrete are outlined. The retardation effect as regards capillary chloride transport ('Huckepack-Transport') is characterised by a retardation coefficient. The calculation of time-dependent spatial distribution of water and chloride allows the durability of different concrete grade to be predicted. Here, the service life of the back wall of a rehabilitated avalanche-gallery is calculated under defined requirements.