Coupling Behaviour of Autogenous And Autonomous Self-Healing Techniques 1 for Durable Concrete

Shaaban, Ibrahim ORCID: (2023) Coupling Behaviour of Autogenous And Autonomous Self-Healing Techniques 1 for Durable Concrete. International Journal of Civil Engineering. ISSN 1735-0522 (In Press)

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Recent research on self-healing concrete has shown some drawbacks and conflicts between the 12 different techniques such as difficulty in casting, healing agent release, preparation complexity, 13 high safety requirements against bacteria protection, undesirable expansion, and uncertainty in 14 healing product generation. Despite these limitations, the hybrid technique was suggested and 15 showed promising results. This paper explores the hybridization of the two techniques; 16 autonomous and autogenous by utilizing the B. subtilis bacteria, mineral admixtures like fly 17 ash, and Polyvinyl alcohol fibers (PVA) together. The experimental program involves 18 assessing the self-healing efficiency when coupling the bacteria, fly ash, and PVA fiber by 19 assigning six mixtures, including a control OPC. The six mixtures encountered the Bacteria 20 addition at certain concentrations and varying PVA fiber percentages; 1, 1.5, and 2% while 21 partially replacing the cement replacement with 20% fly ash, while the last mixture combines 22 both the bacteria, fly ash and 1% PVA fiber. Mechanical properties such as compressive and 23 flexural strength, in addition to, water absorption and sorptivity as transport properties were 24 examined for concrete repair and restoration purposes. The results reveal that the B. subtilis 25 bacteria significantly enhance the compressive and flexural strength recovery along with 26 lowering sorptivity and absorption rate compared to those with PVA addition when exposed to 27 wet and dry cycles of curing at 28 days of age. The coupling effect, on the other hand, provides 28 a substantial gain in strength of 63% at a longer age (56 days), indicating the potential of this 29 approach for long-term concrete repair. Despite the challenges of the B. subtilis survival 30 bacteria, the coupling of both bacteria and PVA fiber demonstrates superior performance in 31 maintaining the durability of repaired concrete in the long term.

Item Type: Article
Keywords: self-healing techniques; absorption; durability; mechanical properties; concrete 33 repair; crack widths.
Subjects: Construction and engineering
Depositing User: Eilish McLaughlin
Date Deposited: 08 Jan 2024 15:56
Last Modified: 06 Feb 2024 16:18

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