2014 Fiscal Year Research-status Report
Evaluation system on water transport properties of cracked concrete under environmental conditions
| Project/Area Number |
26820175
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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) |
2014-04-01 – 2016-03-31
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| Keywords | mortar / water absorption / crack width / gravity / ECC / crack distribution |
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| Outline of Annual Research Achievements |
In FY2014, water absorption of cracked mortars was investigated experimentally. Mortar specimens were prepared, and crack with different width was induced using tensile splitting load. It was found that although crack accelerated water absorption greatly, crack width does not influence the absorption ratio after long time absorption. Furthermore, the influence of gravity can be neglected since similar absorption ratios were obtained for different absorption direction.
Also, using a two phase absorption model, water absorption behaviors of Engineered Cementitious Composites (ECC) materials with different crack density and distribution were simulated and compared with test results. It was found that higher crack density caused faster absorption and larger absorbed water amount. This is because that cracks become convenient channels for water ingression into cement matrix. Besides, for ECC with severe cracking, cracks are not uniformly distributed but localized in some areas, which causes different water distribution in the absorption. In the analysis, such a process can be reasonably simulated by two dimensional analysis.
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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
As the research plan, water behaviors of cracked concrete should be experimentally studied and a water transport model should be established. In the research work of FY2014, such experiment was done for mortar specimens, and the influence of crack became clear. Also, a two phase absorption model was established, and simulation of water absorption of ECC material was done successfully.
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| Strategy for Future Research Activity |
The work in FY2014 focused on water behaviors of mortar specimens and ECC materials. In FY2015, the research should be extended to normal concrete, for both experiment and analysis. Furthermore, for the experiment, except for water absorption ratio measurement, water profile should be observed using proper method, in order to trace water penetration in crack more precisely. For the analysis, its accuracy should be improved.
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| Causes of Carryover |
For some amounts, they are planned to purchase Workstation and related software for the numerical analysis, and high resolution digital camera for water profile observation. However, in FY2014, the experiment was focused on measurement of water absorption ratio, so the purchase of digital camera was not conduct. Also, because the existing computer in the laboratory can satisfy the requirements of current analysis, the purchase of Workstation was not conduct either.
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| Expenditure Plan for Carryover Budget |
In FY2015, after the improvement of current analysis model, more complicated analysis case for water penetration in cracks, which needs high performance computer, will be carried out. Therefore, a Workstation and related analysis software will be purchased. Also, water profile observation in cracked concrete will be carried out, and a high resolution digital camera will be purchased.
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Research Products
(1 results)
