2002 Fiscal Year Final Research Report Summary
A Study on the Physical and Chemical Deterioration of Hardened Mortar due to Leaching Calcium
| Project/Area Number |
12450177
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Independent Administration Institution, Public Works Research Institute (2002)
Niigata University (2000-2001) |
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Principal Investigator |
HISADA Makoto Public Works Research Institute, Structural Management Technology Research Team, Senior Researcher, 技術推進本部, 主任研究員 (80238295)
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| Co-Investigator(Kenkyū-buntansha) |
SAEKI Tatsuhiko Niigata University, Dept.of Civil Eng and Architecture, Associate professor, 工学部, 助教授 (90215575)
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| Project Period (FY) |
2000 – 2002
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| Keywords | leaching calcium / Ca(OH)_2 / CSH / AFm / modified acid rain / pH / pH |
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| Research Abstract |
The purpose of this study is to determine the change of concrete quality by leaching Ca^<2+> from concrete. In this investigation, the electrical leaching tests were mainly carried out by using hardened mortar, and these tests were set up as Ca^<2+> was electrically dissolved out from specimens. And the physical and chemical changes of hardened mortar due to the leaching Ca^<2+> were measured in this study. From these test results, the mechanisms of leaching Ca^<2+> from mortar were experimentally found out.
According to the relation between the amount of Ca(OH)_2 and that of CSH, it can be recognized that leaching out of Ca(OH)_2 and CSH are related in all cement mixtures, durations and depth. Moreover, the remaining CSH can be estimated at most 0.3 g/cm^3 when Ca(OH)_2 was completely leached out from the mortar specimens.
In dissolving process, it is general that the dissolubility of solid can be evaluated basically by the solubility and surface area of the solid. From these viewpoints, the authors can conclude that CSH in concrete can be dissolved at early stage of service time because of its large surface area, although the solubility of CSH is comparatively smaller than that of Ca(OH)_2.
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