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Use of bacteria to repair cracks in concrete. Cem Concr Res

Magnel Laboratory for Concrete Research, Ghent University, Department of Structural Engineering, Technologiepark Zwijnaarde 904, B-9052 Ghent, Belgium
Cement and Concrete Research (Impact Factor: 3.85). 03/2013; DOI: 10.1016/j.cemconres.2009.08.025

ABSTRACT As synthetic polymers, currently used for concrete repair, may be harmful to the environment, the use of a biological repair technique is investigated in this study. Ureolytic bacteria such as Bacillus sphaericus are able to precipitate CaCO3 in their micro-environment by conversion of urea into ammonium and carbonate. The bacterial degradation of urea locally increases the pH and promotes the microbial deposition of carbonate as calcium carbonate in a calcium rich environment. These precipitated crystals can thus fill the cracks. The crack healing potential of bacteria and traditional repair techniques are compared in this research by means of water permeability tests, ultrasound transmission measurements and visual examination. Thermogravimetric analysis showed that bacteria were able to precipitate CaCO3 crystals inside the cracks. It was seen that pure bacteria cultures were not able to bridge the cracks. However, when bacteria were protected in silica gel, cracks were filled completely.

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    • "À1 ) and CaCl 2 $2H 2 O (49 g l À1 ) (Van Tittelboom et al., 2010 "
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    • "The self-healing way to improve the mechanical property and transmission performance of concrete matrix through solidification techniques based on polymer capsule was studied in previous papers (need supportive references). In addition to the further improvement of this novel approach for the crack repairing and mechanical performance recovery, its attention has been turned to the recovery of degradations induced by reinforcement corrosion , which is generally regarded as the major threatening in marine environments [14] [15]. It is well known that the reinforcement http://dx.doi. "
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    Cement and Concrete Composites 11/2014; 56. DOI:10.1016/j.cemconcomp.2014.10.006 · 2.76 Impact Factor
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    • "It has been applied in the healing and strengthening a range of construction materials, including building stone (Le Métayer-Levrel et al., 1999) and soils (DeJong et al., 2006; Van Paassen et al., 2010), and has been shown to work in both laboratory and field environments. Similar technologies have been considered in the self-healing of cementitious materials (Van Tittelboom et al., 2010), adapting soil microbial processes for use in this environment. It is the persistence of bacteria, particularly in the form of spores (Sporosarcina pasteurii and other organisms used are known to sporulate), that may already imbue this ground improvement technique with self-healing properties, as such spores are likely to remain encased within the calcium carbonate matrix following cementation, ready to respond should the matrix be fractured in some way. "
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