2017 Fiscal Year Annual Research Report
Surface chemistry of calcium aluminosilicate hydrate (C-A-S-H) for ions immobilization and transport in low carbon cementitious materials
| Project/Area Number |
16K18129
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| Research Institution | Hokkaido University |
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Principal Investigator |
Y Elakneswaran 北海道大学, 工学研究院, 特任准教授 (60769090)
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | Cement chemistry / C-A-S-H / Surface chemistry / Ionic adsorption / Ionic ingress / Modelling |
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| Outline of Annual Research Achievements |
This year study focused on C-A-S-H. C-A-S-H with Ca/(Si+Al) of 0.8, 1.0 and 1.4 were synthesized. The aluminium replacement was 2, 4, 8 and 16 %. The synthesized C-A-S-H were characterized by different experimental techniques. The surface site density of SiOH and AlOH on C-A-S-H were determined from the NMR experimental results. Triple layer surface complexation model (CD MUSIC) was developed to understand the interface between C-A-S-H and the aqueous solution. The surface electrical properties of the C-A-S-H mainly the equilibrium constants for dissociation and adsorption of ions were estimated by fitting the potentiometric titration and zeta potential experimental data the modelling results. In addition to the characterization of C-A-S-H, batch experiments were conducted for chloride binding in slag-blended cementitious materials and the chloride profiles were verified with surface complexation modelling results. It is published in a Journal. The chloride binding model was coupled with reactive transport model to predict chloride ingress in slag-blended cementitious materials. The findings were also published in an Journal. The developed mode and experimental results and findings will contribute to understanding the durability performance of cementitious materials in various environments including nuclear waste repositories.
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