Durability of concretes with ferrous dusts exposed to liquid chemically aggressive environments

conference paper

English

There are currently increasing the risks and frequency of use of concretes exposed to chemically aggressive environments in categories XA 1 through 3 rated according to ČSN EN 206-1. Requirements for composition of such applied concretes are defined in the aforementioned standard only by minimum cement dose, maximum water-cement ratio or minimum concrete strength class. However, such solutions are not sufficient in many cases and, at the same time, they are not economical or ecological one at all. The objective of this research was to evaluate the impact of different doses of ultra-fine grained ferrous dusts on durability of concretes placed in chemically aggressive liquid environments (high concentrations of sulphate, chloride ions and acid environments). Ferrous dusts are industrial wastes generated during manufacture of crude iron in blast furnace. The raw material is classified as a dangerous waste and, therefore, hard to be disposed. On the other hand, flying dust can be used as an active additive in concrete improving some of its properties and it may also actively affect the course of concrete hydration, thus, either improve concrete quality or decrease concrete quantity. Concrete resistance to acid carbonate or sulphate corrosion can be improved by addition of ferrous flying dust which does not settle in fresh suspension, just on the contrary, seals porous structure improving, thus, resistance. To reach necessary level of anti-corrosion protection, the following properties of ferrous dusts are important: fineness, active ingredient content (purity), dose, kind and perfect dispersion in cement matrix.

Durability of concretes, ferrous dusts, chemically aggressive environment

HELA, R.; HUBERTOVÁ, M.

2005

1. 11. 2005

Taylor&Francis/Balkema

Cape Town

0-415-39655-7

Concrete repair, Rehabilitation and Retrofitting

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