2018 Fiscal Year Research-status Report
Predicting long-term durability performance of cement systems from the nanost ructure and properties of calcium aluminosilicate hydrate (C-A-S-H) gels
| Project/Area Number |
18K04297
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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, 准教授 (60769090)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | Cement chemistry / C-A-S-H / surface complexation / modelling |
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| Outline of Annual Research Achievements |
C-A-S-H with Ca/(Al+Si) of 0.8, 1.0 and 1.5 were synthesized and
characterized by various experimental methods to determine its nanostructure. Titration and zeta potential experiments were performed to understand the surface electrical properties of C-A-S-H. The experimental data were fitted to a triple-layer surface complexation modelling (CD-MUSIC) to determine the surface functional groups of C-A-S-H and the associated equilibrium constants values. The results of C-A-S-H were compared with that of C-S-H to understand the incorporation of aluminum in the gel. The density of sites increases with calcium to silica ratio. It is found that C-S-H or C-A-S-H has strong and weak binding sites for the dissociation and adsorption of ions.C-S-H has strong and weak of SiOH while C-A-S-H has strong and weak of SiOH and AlOH surface sites. The determined equilibrium constant for the dissociation of SiOH for both strong and weak sites of C-S-H is independent of calcium to silica ratio. The same tendency was observed in C-A-S-H as well. Furthermore, the dissociation equilibrium constant for weak sites of SiOH and AlOH is equal and independent of calcium to silica ratio of C-S-H. The results found in this stage will be used to predict the interaction behavior of various ions toward C-S-H and C-A-S-H.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
WP1 and WP2 are completed in FY2018, which is according to the research plan.
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| Strategy for Future Research Activity |
Work-package 3: Interaction between C-A-S-H and ions: Adsorption
Work-package 4: Interaction between C-A-S-H and ions: Absorption
Work-package 5: Interaction between C-A-S-H and ions: Exchange
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| Causes of Carryover |
I spent less money on renting equipment for experiments. I will use it in this year for rental and article costs.
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