2001 Fiscal Year Final Research Report Summary
Research on Deterioration Diagnosis and Optimum Repair System for Deteriorated Existing Concrete Structures
| Project/Area Number |
12305029
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
土木材料・力学一般
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| Research Institution | The University of Tokyo |
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Principal Investigator |
UOMOTO Taketo Institute of Industrial Science, The University of Tokyo, Professor, 生産技術研究所, 教授 (80114396)
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| Co-Investigator(Kenkyū-buntansha) |
MEGURO Kimiro Institute of Industrial Science, The University of Tokyo, Associate Professor, 生産技術研究所, 助教授 (40222343)
KOSEKI Junichi Institute of Industrial Science, The University of Tokyo, Associate Professor, 生産技術研究所, 助教授 (30272511)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Maintenance system for concrete structures / Salt damage / Chemical attack / Deterioration diagnosis / Surface coating of concrete / Epoxy resin injection / Prediction of the change of performance / The most suitable repair method |
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| Research Abstract |
The target of this research is to develop a new maintenance system for concrete structures. The system is composed of the following three phases: 1) deterioration diagnosis for deteriorated concrete structures, 2) prediction of the change of performances for existing concrete structures, and 3) selection of the most suitable repair method The following results are obtained through this project.
1. A new deterioration diagnosis system was developed. The system is a user interface computer program that can be used not only by the professionals but also by normal civil engineers. Using photographs and questions to be answered, degree of deterioration of a structure can be easily obtained through personal handy-type computers. The algorism used in the program is based on fuzzy estimation theory considering the uncertainties of the answerers.
2. A new prediction method of concrete deterioration was developed when chlorides corrode steel reinforcing bars through a crack. The method is based on
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a simple apparent diffusion theory of chlorides through concrete, enabling the prediction by obtaining the data at periodic inspection. The problem still to be solved is to predict the movement of chlorides in cyclic wet and dry environment.
3. A new prediction system was developed when concrete deteriorate due to chemical attack, especially sulfuric acid Research in this field was little and this research may be the first work being done to predict the deterioration. After clarifying the effects of many factors which influence the degradation of concrete by experiment the mechanism of the degradation can be explained mainly by the type of binders used, water to cement ratio and concentration of hydroxides. It was clarified that the degradation of concrete can be predicted using these three factors. Cyclic wet and dry environment is also the remaining problem.
4. Performance of surface coating of concrete under cyclic load was studied The results show that suitable selection of the type of coating can be done by checking the elongation ability of the coating at cracks. The test results on the effects of impregnation of resin into cracks show that there is a close relation between durability and mechanical properties of concrete with degree of impregnation into cracks. Less
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