Cathodic polarization properties of steel bars in concrete mixed with aerobic microorganism of bacillus subtilis

Author(s): K. Kawaai, I. Ujike, S. Fujioka, T. Nishida and A. Saito
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume I
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-209-1 (Volume1)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 259-266
Total Pages: 288
Language : English

Abstract: Dissolved oxygen in pore solution is often a controlling factor determining the rate of corrosion processes of steel bars in concrete. This study reports on cathodic polarization properties of steel bars in mortar specimen mixed with aerobic microorganisms. The properties are essentially associated with the permeability of dissolved oxygen in pore solution. This could be affected via metabolic activities of aerobic bacillus subtilis mixed in hardened mortar specimens. Mortar specimens with segmented steel bars were prepared using culture solution as a partial replacement of mixing water. Cathodic polarization curve was measured at the age of 91 days after the specimens were exposed to chloride-induced corrosion tests through dry and wet cycles. The results indicate that the rate of oxygen permeability inferred based on limiting current density is substantially smaller in the case of mortar specimens mixed with the bacillus subtilis. This can be explained by the fact that the dissolved oxygen is consumed by the aerobic processes of bacillus subtilis present in hardened mortar specimen during the monitoring periods. Based on the results obtained, the presence of aerobic bacillus subtilis resulted in higher resistance against corrosion processes, which was confirmed by the results of half-cell potential and corrosion current density. There is a strong possibility that the reduced dissolved oxygen in pore solution through the aerobic processes could enhance the corrosion resistance in cracked mortar specimens.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00

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