Journal
CONSTRUCTION AND BUILDING MATERIALS
Volume 224, Issue -, Pages 815-822Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.conbuildmat.2019.07.129
Keywords
Self-healing concrete; Microbial consortia; Aragonite; Calcite; Economic evaluation
Categories
Funding
- National Science Foundation of China [51708386, 51608345, 51678384]
- China Postdoctoral Science Foundation [2015M570241, 2016M591416, 2017T100170]
- Open Project of Key Laboratory of Environmental Biotechnology, CAS [kf2016004]
- State Key Laboratory of Pollution Control and Resource Reuse Foundation [PCRRF17021]
- Scientific and Technological Project of Shanxi Province [201701D221230]
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Microbially induced CaCO3 precipitation (MICP), mainly in the form of calcite, has been reported to be an efficient approach for self-healing cracks in concrete. However, little is known about the implementation of aragonite, the other common crystalline form of CaCO3, in bioconcrete. Therefore, a systematic investigation of the crystal polymorphs and the healing efficiency of different cultures, i.e., two microbial consortia under anaerobic (MC-Aa) and anoxic (MC-Ao) conditions and nonureolytic pure-culture bacteria (Bacillus cohnii), was conducted in this study. The results showed that the MC-Ao agent exhibited the maximum values of completely healed crack widths (1.22 mm) after 28 d of healing, which is larger than the values of 0.79 and 0.73 mm for B. cohnii and MC-Aa, respectively. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analyses confirmed that the biominerals induced by MC-Aa and B. cohnii are calcite, while those of MC-Ao were 82% aragonite and 18% calcite. It is noteworthy that this proportion of aragonite is the highest reported level for the MICP system to date. In addition, economic evaluation verified that the microbial consortia resulted in a 61% decrease in production costs compared to pure cultures. The intriguing findings obtained in this study may provide a scientific basis for the potential implementation of microbial consortia under anoxic conditions, such as a new self-healing agent, in bioconcrete. (C) 2019 Elsevier Ltd. All rights reserved.
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