Use of 3D mini-vascular networks to protect and deliver bacterial spores in self-healing concretes

Justo Reinoso, Ismael, De Nardi, Cristina, Reeksting, Bianca, Gardner, Diane ORCID: https://orcid.org/0000-0002-2864-9122, Jefferson, Anthony ORCID: https://orcid.org/0000-0002-2050-2521, Gebhard, Susanne and Paine, Kevin 2022. Use of 3D mini-vascular networks to protect and deliver bacterial spores in self-healing concretes. Presented at: 8th International Conference on Self-Healing Materials, Milan, Spain, 20-22 June 2022.

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Abstract

Significant research has been conducted over the last two decades to develop self-healing concretes able to reduce or completely close cracks that invariably appear in concrete structures due to the relatively low tensile strength of concrete. Different strategies have been investigated, including the use of microbially induced calcite precipitation. This strategy relies on the metabolic activity of bacteria combined with the presence of calcium precursors within the concrete matrix to induce the precipitation of calcium carbonate crystals within the crack. However, a significant challenge of this bacteria-based strategy is the protection of the bacterial spores during the initial mixing and the later successful release of a sufficient number of spores once the crack is formed. In this study, an innovative combination of microbially induced calcite precipitation and 3D printed mini-vascular networks has been investigated to develop autonomous self-healing concrete. 3D printed tetrahedral mini-vascular networks – made of polylactic acid (PLA) and referred to as TETs – consist of a series of interconnected channels capable of storing, protecting and releasing an efficient number of bacterial spores once a threshold value of mechanical stress (damage) is exceeded. TETs were embedded in prismatic concrete beams, whilst nutrients and calcium precursors were directly added to the mixing water. After curing for 28 days submerged in water, the concrete beams were cracked by three-point bending until a crack width of 0.45 mm was obtained. The decrease of the crack area was quantified using image binarization to evaluate the efficacy of the TETs to protect and successfully release the bacterial spores suspension. The results show that PLA TETs have no adverse effect on the viability of the spores and that bacteria-based self-healing can be efficiently achieved when using these novel 3D printed mini-vascular networks to protect bacterial spores in self-healing concretes.

Item Type:	Conference or Workshop Item (Paper)
Status:	Unpublished
Schools:	Engineering
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TH Building construction
Funders:	EPSRC
Last Modified:	06 Apr 2023 11:34
URI:	https://orca.cardiff.ac.uk/id/eprint/158127

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