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Immobilized bacteria with pH-response hydrogel for self-healing of concrete

  • Concrete is significant for construction. A problem in application is the appearance of cracks that will damage its strength. An autogenous crack-healing mechanism based on bacteria receives increasing attention in recent years. The bacteria are able to form calcium carbonate (CaCO3) precipitations in suitable conditions to protect and reinforce the concrete. However, a large number of spores are crushed in aged specimens, resulting in a loss of viability. A new kind of hydrogel crosslinked by alginate, chitosan and calcium ions was introduced in this study. It was observed that the addition of chitosan improved the swelling properties of calcium alginate. Opposite pH response to calcium alginate was observed when the chitosan content in the solution reached 1.0%. With an addition of 1.0% chitosan in hydrogel beads, 10.28% increase of compressive strength and 13.79% increase of flexural strength to the control were observed. The results reveal self-healing properties of concretes. A healing crack of 4 cm length and 1 mm width was observed when using cement PO325, with the addition of bacterial spores (2.54–3.07 × 105/cm3 concrete) encapsulated by hydrogel containing no chitosan.

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Metadaten
Author of HS ReutlingenKrastev, Rumen
DOI:https://doi.org/10.1016/j.jenvman.2020.110225
ISSN:0301-4797
eISSN:1095-8630
Erschienen in:Journal of environmental management
Publisher:Elsevier
Place of publication:Amsterdam
Document Type:Journal article
Language:English
Publication year:2020
Tag:calcium alginate; chitosan; concrete; crosslink; self-healing; spores
Volume:261
Page Number:6
First Page:1
Last Page:6
Article Number:110225
DDC classes:333.7 Natürliche Ressourcen, Energie und Umwelt
Open access?:Nein
Licence (German):License Logo  In Copyright - Urheberrechtlich geschützt