Research group "Alkali-silica reaction in concrete components under simultaneous cyclic loading and external alkali supply"

Project duration: 2012 to 2020

Up to now, extensive investigations concerning a damaging alkali-silica reaction (ASR) in concrete have predominantly considered the so-called internal alkali supply, in which the alkalis enter the concrete exclusively via the concrete constituents. In the course of use, however, other alkalis can be added from the outside, which can influence a damaging ASR even more strongly than the internal alkalis. Buildings exposed to seawater and traffic areas to which alkali-containing de-icing agents are applied, for example, are exposed to an external alkali supply. In the case of traffic surfaces, additional traffic stresses as well as additional thermal and hygric constraints can cause microcracks (degradation), which promote the penetration of alkali-containing media to greater depths. Furthermore, the alkali penetration process is intensified by fulling. The aim of the research group is, on the one hand, to gain scientific knowledge about the interaction mechanisms of cyclic loading and external alkali input as well as their effects on the intensity of an ASR. Based on this, the current uncertainties in the entire concrete construction regarding ASR can be defused and corresponding tools (models) can be provided. This should make it possible to derive reliable rules for the selection of concrete raw materials, the determination of concrete compositions, the dimensioning of structural components, and special, easy-to-implement measures during use.