The issue of sustainability is a major spur to innovation in the flied of civil engineering where the importantrole is decreasing the detrimental effects on environment and save raw materials and energy. Micro silica is a by-productof the industrial manufacture of ferrosilicon and metallic silicon in high temperature electric arc furnaces and is used asan additive for improving concrete properties. The paper presents the results of chemical corrosion and bio-corrosiontests on concrete samples with 5% addition of microsilica as well as on concrete samples with only Portland cement.Chemical corrosion, simulated by sulphuric acid with pH of 4.2, and bio-corrosion, simulated by sulphur-oxidisingbacteria Acidithiobacillus thiooxidans, were investigated in terms of basic concrete’s elements leachability. Dissolvedamounts of Si and Ca due to both chemical attack and biocorrosion were measured in the period of 3 months. Theleaching trends were analysed using a mathematical approach for better interpretation of the results. The correlationanalysis confirmed the different leaching trends comparing bio-corrosion and chemical corrosion processes. A highdependency was observed between leaching of Ca and Si from concretes prepared with ordinary cement. In case ofconcrete sample with microsilica addition no correlation was found out.

DOI: https://doi.org/10.3846/enviro.2017.038