2023 Fiscal Year Annual Research Report
Modeling and re-corrosion evaluation of patch repaired concrete subjecting to chloride attack
| Project/Area Number |
19K04547
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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) |
2019-04-01 – 2024-03-31
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| Keywords | patch repaired concrete / crack / multi-scale model / chloride penetration / water repellency / hydrophobic treatment / reinforcement corrosion |
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| Outline of Annual Research Achievements |
A multi-scale approach is developed to evaluate the performance of water and chloride penetration and rebar re-corrosion in patch repaired concrete structures when cracks take place in the repaired mortar. Water and chloride in the cracked mortar is simulated based on micro-scale models considering pore structure of repair mortar, crack pattern, and water and ion exchange between mortar and cracks. The accumulative chloride content at rebar surface is used to evaluation re-corrosion initiation. In addition, remaining chloride content in concrete substrate and the hydrophobic treatment on repaired mortar are also introduced in the approach to consider more complicated practical conditions. Experimental studies were carried out on chloride migration by performing electrophoresis test and chloride binding by immersion test, using different types of repair mortars such as slag mortar and polymer cement mortar. The obtained chloride diffusion coefficients and binding parameters are used in the analytical models. Water, chloride penetration, and rebar re-corrosion are simulated using the developed multi-scale models, comparing the simulation results with experiment data from past studies for validation. The results indicate that the accelerated corrosion process of patch repaired structures under cracked conditions highly depends on the type of repair mortar and crack pattern, while hydrophobic treatment on repair mortar can effectively postpone corrosion owing to the increase of water repellency.
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