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Bacteria mediated remediation of concrete structures

Title: Bacteria mediated remediation of concrete structures
Author(s): Henk M. Jonkers, Arjan Thijssen
Paper category : conference
Book title: 2nd International Symposium on Service Life Design for Infrastructures
Editor(s): K. van Breugel, Guang Ye, Yong Yuan
Print-ISBN: 978-2-35158-096-7
e-ISBN: 978-2-35158-097-4
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 833 - 840
Total Pages: 8
Nb references: 17
Language: English

Abstract: One aspect that could particularly contribute to increased service life of concrete structures is autonomous crack-healing potential. Substantial self-healing of cracks in concrete will decrease material permeability and reduce risk of premature reinforcement corrosion and concrete matrix degradation. Since several years a novel type of self-healing concrete in which bacteria mediate the production of crack-filling material is under development in our laboratory.
The specific mechanism of crack-healing in this case is based on concrete matrix-incorporated dormant but viable spores of specific alkali-resistant bacteria which, after activation by crack-ingress water, produce inorganic mineral precipitates by conversion of organic precursor compounds. Experimental results indicate that the quality of mineral precipitates produced depend on species of bacteria and type of precursor compound involved. Environmental scanning electron microscopic (ESEM) analysis revealed that a bacterial isolate originating from soil samples produced robust elongated sphere-shaped 50-100 µm-sized precipitates from the conversion of calcium lactate. In contrast, another isolate originating from an alkaline soda lake produced larger 0.1-1 mm-sized plate-like precipitates from sodium glutamate. Energy dispersive X-ray analysis (EDAX) indicated that the plate-like mineral precipitates are probably calcium carbonate-based. Light microscopic analysis of cracked and subsequently water incubated concrete specimens revealed perfect crack-healing of bacteria-based but not of control specimen. We therefore conclude that bacteria-based self-healing concrete represents a durable and particularly sustainable alternative to classical, but also to strictly chemically-based self-healing concretes.

Online publication: 2011-04-20
Publication type : full_text
Public price (Euros): 0.00

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