Author(s): Yusuf Ç. Erşan, Nico Boon and Nele De Belie
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume II
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-210-7 (Volume 2)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 475-484
Total Pages: 308
Language : English

Abstract: Over the last decades, self-healing technologies for concrete have been developed with the aim of immediate crack repair, which implies avoiding manual labour and durability problems. One of the technologies explored, applies bacteria to induce calcium carbonate precipitation in the crack, which would ideally block the crack completely against ingress of aggressive agents leading to concrete deterioration and corrosion of the steel reinforcement. Several types of pure axenic bacterial strains have been tested for this purpose, including ureolytic strains [1] and aerobic heterotrophic bacteria [2]. Recently, our group revealed that with denitrifying bacterial cultures, enhanced calcium carbonate precipitation performances could be achieved in nutrient- poor environments [3]. Biological NO3 - reduction takes place during the microbial oxidation of organic matter by use of NO3 - as an electron acceptor instead of O2 and therefore has the benefit that precipitation can take place in oxygen limited environment, such as the inner part of a concrete crack. Nitrate reduction furthermore leads to the production of NO2 - which is known as a corrosion inhibitor for steel in concrete. By using an in-house produced non-axenic culture, cultivated in a sequential batch reactor, and named “activated compact denitrifying core” (ACDC) [4] passivation of steel in corrosive chloride containing electrolyte solution could be obtained [5]. This ACDC culture did not require additional protection for application in mortar and performed better than protected axenic cultures in all tested conditions.

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

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