The chloride-induced corrosion was identified as a major cause of the damage of reinforced concrete structures. In research projects the determination of chloride resistance of concrete and its effect sizes was examined.
In practice there are cases, where the limit of the chloride migration coefficient will be exceeded, for which no conclusive causes that can be traced to known contexts. Targeted measures for safety provision of a sufficient resistance are in these cases impossible. This unsettles concrete producers and users.
That even though intensive efforts, no reliable control variables are found for the chloride resistance indicates that factors are relevant,
whose sizes in the production control could not be recorded. The aggregate exerts a significant influence on the fresh and hardened concrete properties. Detailed investigations on the influence of aggregate on the chloride resistance are lacking however.
It can be concluded that nowadays recognized properties of the aggregate have a relevant influence on the chloride resistance of concrete-exercise.
The hypothesis is: the grain size distribution, petrographic composition and particle shape of fine aggregate exert a relevant influence on the chloride resistance of concrete.
With laboratory tests on selected aggregates, the hypothesis will be identified in Phase 1 and the significant influencing variable be defined. On confirmation of the hypothesis in laboratory tests the implementation and application in practice will be examined in Phase 2.
The SIA standard committee 262 is interested in the topic.