Modeling and re-corrosion evaluation of patch repaired concrete subjecting to chloride attack
Project/Area Number |
19K04547
|
Research Category |
Grant-in-Aid for Scientific Research (C)
|
Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 22010:Civil engineering material, execution and construction management-related
|
Research Institution | Saitama University |
Principal Investigator |
欒 堯 埼玉大学, 理工学研究科, 助教 (20725288)
|
Project Period (FY) |
2019-04-01 – 2024-03-31
|
Project Status |
Granted (Fiscal Year 2022)
|
Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
|
Keywords | patch repaired concrete / chloride / water repellency / crack / corrosion / multi-scale model / chloride migration / blast furnace slag / water repellent agent / water penetration / silica fume / repair mortar / electrophoresis / capillary absorption / SHCC / repair materials / simulation / polymer cement / chloride attack / multi-scale modeling |
Outline of Research at the Start |
Patch repair is the mostly used method for repairing concrete subject to chloride attack. However, re-corrosion of the repaired concrete in short time is often reported because of inappropriate treatment. This study will focus on establishing an approach of modeling and evaluation of patch repaired concrete. Key factors, for example, chloride transport and the natural potential difference between the old concrete and the repaired part, will be studied. Their effects will be integrated into chloride transport and corrosion models for reasonably evaluating the risk of re-corrosion.
|
Outline of Annual Research Achievements |
In FY2022, water penetration and chloride migration of repair materials that were treated with water repellent agents, as well as their shrinkage and strength properties, were studied experimentally. The results indicated that the combination of hydrophobic treatment with repair materials effectively improved water and chloride penetration resistance under cracked conditions. Shrinkage was also reduced for treated repair materials, but the reduction of strength still remains an issue that needs to be solved in the future. In addition, bond strength of repair material and concrete substrate was also tested with different interfacial treatment and concrete removal technology. For the steel corrosion of patch repaired concrete, the influence of crack width in repair materials has also been tested. It was found that corrosion degree increased with increasing crack width, which accelerated chloride penetration significantly.
|
Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The progress of experimental and analytical studies on water and chloride penetration of patch repaired concrete followed the research plan. Regarding the corrosion of steel bars in patch repaired concrete, the experiment work was late in last fiscal year because of the Covid-19. In this year, the corrosion test has been started and the progress generally followed the plan.
|
Strategy for Future Research Activity |
In the FY2023, steel corrosion test of patch repaired concrete will be continued for including more factors such as temperature and relative humidity as well as repair material type. Comparison between the test and numerical analysis will also be performed.
|
Report
(4 results)
Research Products
(10 results)