2022 Fiscal Year Research-status Report
A multi-scale approach for modeling self-healing concrete by coupling water ingress and crack healing process
| Project/Area Number |
22K04257
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| Research Institution | Saitama University |
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Principal Investigator |
欒 堯 埼玉大学, 理工学研究科, 助教 (20725288)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Keywords | self-healing / crack / water penetration / multi-scale model / bacteria / polyvinyl alcohol fiber |
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| Outline of Annual Research Achievements |
In FY2022, a multi-scale model coupling water penetration and the self-healing process was established. The water penetration process was integrated with three processes, water penetration in matrix and cracks, respectively, and water absorption from crack to matrix. The crack healing process was tentatively modeled in relation to elapsed time and initial crack width. The numerical analysis using the multi-scale model can qualitatively simulate the gradual crack healing process with drying-wetting cycles, resulting in a gradual increase in water resistance. The process was visualized using two-dimensional contours reasonably.
In addition, self-healing experiment was performed using two different technologies: the application of bacteria and polyvinyl alcohol (PVA) fibers, respectively. The crack healing process was observed periodically by recording crack width changes. Water absorption test was also performed before and after self-healing, exhibiting reduced accumulative water in the specimens.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
As written in the research plan, the multi-scale model coupling the crack healing process and water penetration should be established first. Meanwhile, experiments of self-healing should be performed to offer data for verification and clarify the factors affecting the self-healing process. In the past year, the model has been established as the plan and will be enhanced further next year. Also, two different technologies, using bacteria and polyvinyl alcohol (PVA) fibers, respectively, have been performed as the plan.
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| Strategy for Future Research Activity |
In FY2022, different environmental conditions for temperature and relative humidity will be applied to the self-healing experiment. In addition to crack width change, thermogravimetric analysis (TG) and X-ray diffraction tests will be performed to analyze the chemical composition of the self-healing products. According to the results, the multi-scale model will be enhanced by improving the chemical reaction model to reasonably reflect the precipitation of different products.
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| Causes of Carryover |
In FY2022, the main work was focused on the establishment of the analysis model, so there was no expense on the amount. In FY2023, some amount will be paid for purchasing necessary consumables for experiments. Also, devices will be purchased to facilitate the experiment, for example, a high-resolution camera and software for observing crack resolution and digital image analysis. XRD and computed tomography (CT) will be performed using devices in the analysis center of Saitama University, so the service fee will be paid.
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Research Products
(1 results)
