Evaluation of Cyclic Healing Potential of Bacteria-Based Self-Healing Cementitious Composites

Ismael Justo-Reinoso, Bianca J. Reeksting, Andrew Heath, Susanne Gebhard and Kevin Paine
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Ismael Justo-Reinoso: Centre for Innovative Construction Materials, Department of Architecture and Civil Engineering, University of Bath, Bath BA2 7AY, UK
Bianca J. Reeksting: Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
Andrew Heath: Centre for Innovative Construction Materials, Department of Architecture and Civil Engineering, University of Bath, Bath BA2 7AY, UK
Susanne Gebhard: Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
Kevin Paine: Centre for Innovative Construction Materials, Department of Architecture and Civil Engineering, University of Bath, Bath BA2 7AY, UK

Sustainability, 2022, vol. 14, issue 11, 1-15

Abstract: At present, little evidence exists regarding the capability of bacteria-based self-healing (BBSH) cementitious materials to successfully re-heal previously healed cracks. This paper investigates the repeatability of the self-healing of BBSH mortars when the initially healed crack is reopened at a later age (20 months) and the potential of encapsulated bacterial spores to heal a new crack generated at 22 months after casting. The results show that BBSH cement mortar cracks that were successfully healed at an early age were not able to successfully re-heal when cracks were reformed in the same location 20 months later, even when exposed to favourable conditions (i.e., high humidity, temperature, calcium source, and nutrients) to promote their re-healing. Therefore, it is likely that not enough bacterial spores were available within the initially healed crack to successfully start a new self-healing cycle. However, when entirely new cracks were intentionally generated at a different position in 22-month-old mortars, these new cracks were able to achieve an average healing ratio and water tightness of 93.3% and 90.8%, respectively, thus demonstrating that the encapsulated bacterial spores remained viable inside the cementitious matrix. The results reported in this paper provide important insights into the appropriate design of practical self-healing concrete and, for the first time, show limitations of the ability of BBSH concrete to re-heal.

Keywords: bacteria; biomineralization; cyclic healing; later age; MICP; re-healing; self-healing concrete (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
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Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:14:y:2022:i:11:p:6845-:d:831111

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