| 研究課題/領域番号 |
19K04547
|
|---|
| 研究機関 | 埼玉大学 |
|---|
研究代表者 |
欒 堯 埼玉大学, 理工学研究科, 助教 (20725288)
|
|---|
| 研究期間 (年度) |
2019-04-01 – 2022-03-31
|
| キーワード | chloride / patch repaired concrete / repair materials / blast furnace slag / simulation / polymer cement / electrophoresis |
|---|
| 研究実績の概要 |
In FY2019, electrophoresis test was carried out to investigate effective diffusion coefficient for three repair mortars made from ordinary Portland cement (OPC), blast furnace slag (BFS), and polymer cement (PC), as well as existing concrete. The coefficients were found different and used for numerical analysis. Combination of existing concrete and repair layer was also investigated by electrophoresis. Weak zone was found in the interface in the cases when the repair mortar was not appropriately cast at existing concrete, increasing chloride penetration speed. For BFS, chloride binding capacity, both physically and chemically, was studied experimentally for different water-to-binder ratios, slag ratios, and temperatures.
Meanwhile, numerical simulation for the chloride penetration of patch repaired concrete was performed. One-dimensional FEM analysis was carried out at the depth direction of concrete cover, considering different cases, such as different repair materials, repair depth, remained chloride amount before repair, and whether chloride absorbent is used or not. The results were reasonable qualitatively and will be compared with experiment in the future. In addition, two-dimensional FEM analysis was also conducted for the cases when cracks arise at the surface of new repair layer or the interface between repair layer and existing concrete, showing reasonable results.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
As written in the research plan, chloride diffusion coefficient and chloride binding capacity of repair mortar should be experimentally studied. In the work of FY2019, such studies were carried out. Diffusion coefficient for different repair mortars were found different and then used for numerical analysis. The influence of weak zone at the interface was also confirmed experimentally. Chloride binding capacity for OPC and BFS mortar with different ratios were studied and plausible results were found, which will be used to construct more sophisticated analysis model in the next year.
In addition to experiment, the work about numerical model, which is another main part in the research plan, was also progressed as the schedule. One and two dimensional models were established and simulated considering different cases such as repair materials, repair depth, remained chloride, cracks at surface and interface. This work showed reasonable results qualitatively and becomes a premising foundation for obtaining more precise prediction in the next year.
|
| 今後の研究の推進方策 |
In the FY2020, immersion test of patch repaired concrete will be conducted to obtain chloride profiles and compared with current analysis results. Accordingly, the numerical model will be improved and enhanced by considering more details, such as porosity of repair layer and old concrete, binding isotherm, drying-wetting cycles. Meanwhile, the relationship between immersion test and electrophoresis test will be discussed and established for repair materials as well as the influence of cracks at surface and interface. Furthermore, corrosion test will be launched. Measurement of weight loss and natural potentials for steel bars will be carried out.
|
| 次年度使用額が生じた理由 |
It was planned to purchase a workstation PC for analysis in FY2019. However, the old PC that I owned at present was found to be capable of performing the analysis, so the purchase was not conducted.
In FY2020, a portable steel corrosion meter will be purchased for measuring the potential change of steel bars. In addition, as planned, a new automatic titrator will be purchased for measuring chloride amount. Moreover, some part of the amount will be spent on purchasing experiment materials, such as cement, steel bars, chemicals, and so on. The other part will be spent for travel and registration fees for academic conferences.
|
