材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
65 巻 , 7 号
選択された号の論文の9件中1~9を表示しています
論文
  • 加藤 昌治, 奈良 禎太, 福田 大祐, 河野 勝宣, 佐藤 稔紀, 佐藤 努, 高橋 学
    2016 年 65 巻 7 号 p. 489-495
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー
    Rock masses serve a vital function as natural barriers for geological disposal of radioactive waste; therefore, information on rock permeability is essential. Highly accurate measurement of permeability requires understanding of how temperature changes in the surrounding environment influence measurement results. We performed permeability measurement under conditions with dramatic changes of temperature in the surrounding environment to investigate the influence of such changes on the experimental results. Measurement of permeability with no temperature change was also conducted as reference. All measurements were conducted using the transient pulse method, and the sample material used was Toki granite obtained from Gifu Prefecture in central Japan. We found that temperature changes in the surrounding environment remarkably affected the pressure in reservoirs upstream and downstream, the pressure difference between them, and the confining pressure; all increased when temperature increased for our experimental system. Notably, pressure difference was affected immediately. This difference directly relates to estimation of permeability. As temperature changes significantly affect pressure difference, it is essential to minimize temperature changes in the surrounding environment so as to achieve accurate measurement of rock permeability.
  • 稲積 真哉, 金子 将己, 重松 祐司, 宍戸 賢一
    2016 年 65 巻 7 号 p. 496-501
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー
    Geotechnical utilization of construction wastes has been performed extensively in construction sites, and fluidized soils which is one of the geotechnical utilizations of construction sludges have been widely applied in construction works. In particular, the fluidized soils are used by filling construction works with long-distance and construction works at complicated underground spaces. Therefore, the fluidized soils that higher fluidity is possessed (that is a super fluidized soil) are required in their development. This paper discusses to be developed a super fluidized soils. Specifically, a mechanical characteristic and fluidity performance of developed super fluidized soil are clarified experimentally. The developed super fluidized soil satisfies qualities requested for fluidized soils as a result also it is confirmed that high-fluidity is possessed.
  • 吉谷 拓磨, 宮里 心一
    2016 年 65 巻 7 号 p. 502-508
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー

    “FA-sand” for concrete was the fine aggregate mixed previously with flyash (FA). However, the study about concrete with FA-sand is extremely few, and the further investigation toward to the widespread use is needed. From the above backgrounds, this study investigated the heat of hydration (simplified adiabatic temperature rise tests), the compressive strength, and the durability (chloride penetration depth, carbonation depth) of concrete with FA-sand. That is, concrete whose water cement ratio was 55% and unit water content was 175kg/m3, was made for all cases. After that, the performances of concrete with FA-sand and concrete mixed with FA in the concrete mixing time as the replacement for the fine aggregates were compared. Also the influences of the type and the manufacture method of FA-sand on the performances of concrete were evaluated. The conclusions were as follows; (1) the heat of hydration and the hardened properties of concrete with FA-sand were equal to those mixed with FA in the mixing time. (2) The stored period of FA-sand, the plant and sampling period of FA, the mixer type manufactured FA-sand were not affected on the heat of hydration and the hardened properties of concrete.

  • 青井 洋視, 永野 哲平, 橋本 親典, 渡邉 健, 石丸 啓輔
    2016 年 65 巻 7 号 p. 509-516
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー

    There has been a great demand of using the recycled aggregate and fly ash in the concrete structure. It is known that the compressive strength will increase in the early age when the mineral fine powder, such as fly ash, is mixed into the concrete with a part of the fine aggregate, under the condition of constant unit cement content. However, its mechanism has not been clearly understood until now. In this paper, we made experiments to explain the mechanism of the early strength development by using recycled aggregate mortar. In addition, we examined the influence of the mineral fine powder, which is mixed into the mortar, which extended the strength development of the recycled aggregate mortar from 3 days to 180 days. From the results obtained, we found that in response to the influence of calcium hydroxide in the adhesion cement paste of recycled aggregate, the fly ash had brought forward the early pozzolanic reaction for 28 days. However unlike the pozzolanic reaction of the usual fly ash, the early pozzolanic reaction did not contribute to strength development. By mixing the mineral fine powder, the early strength development had strongly influenced the filler effect of physical action. The mixture of the recycled aggregate mortar using the mineral fine powder as a part of the fine aggregate had brought much larger strength increment ratio than the normal aggregate mortar. The results indicate that the combination of fly ash and recycled aggregate would have a good affinity.

  • 三木 靖浩, 西本 明生, 民谷 隆純
    2016 年 65 巻 7 号 p. 517-524
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー

    The S-phases (γN-phases) of SUS304 steel were prepared using direct current plasma nitriding (DCPN) and active screen plasma nitriding (ASPN). Furthermore, diamond-like carbon (DLC) films on these S-phases were prepared using plasma chemical vapor deposition (PCVD). The nitride layers included the γ'Fe4N phase. The X-ray stress constant K of the nitride layers were evaluated using γN (200)+γ'Fe4N(200) diffraction with CrKα characteristic X-rays. The γN (200)+γ'Fe4N(200) diffraction angle 2θ of DCPN powder and ASPN powder were 73.49° and 72.98°, respectively. The X-ray stress constants of the γN (200)+γ'Fe4N(200) phase nitrided using DCPN and ASPN, E / (1+ν) , were 202 GPa and 153 GPa, respectively. The X-ray stress constant K of the γN (200)+γ'Fe4N(200) phase nitrided using DCPN and ASPN were -2,365 MPa/deg and -1,809 MPa/deg, respectively. The X-ray residual stress of these S-phases prepared using DCPN and ASPN were approximately -5.3 GPa and -2.6 GPa, respectively. On the other hand, Raman microprobe spectroscopy was used for residual stress measurements of the DLC films deposited on these S-phases. The Raman spectra of the DLC films were classified into the disorder (D') peak at 1,150 cm-1, D peak, and graphite (G) peak. The residual stresses in the DLC films on these S-phases as estimated from the Raman shift of the G peak for DCPN and ASPN were -3.2 GPa and -3.0 GPa, respectively. The hardness of the DLC films as determined using the nano-indentation method was very large. It is possible that increases in compressive residual stresses in the DLC films caused decreases in the contact areas and the indentation depth of the indenter, which appeared to cause increases in the Young's modulus and hardness of the DLC films.

  • 緒方 隆志, 荒川 大輔, 松村 栄郎, 西田 秀高
    2016 年 65 巻 7 号 p. 525-531
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー
    Damage and degradation gradually proceed in high temperature components during long-term operation. Prediction of softening and embrittlement which are related to tensile strength and critical crack length respectively, during operation is important for maintaining reliable operation of the components. So far although studies on temper embrittlement were conducted by using artificially produced materials by heat treatments, evaluation of embrittlement for actual long-term used materials were very limited. No data was obtained for long-term used components operating over 300,000 hours. In this study, micro structure observation and, hardness and Charpy impact tests were conducted using the long-term operated steam valve at high temperature for over 300,000 hours. Additional heat treatment at 585C for 4457 hours equivalent to 100,000 hours at 538C was done for the used material to obtain the aged material. Coarsening of carbide precipitation and decrease of dislocation structures were observed by a transmission electron microscope both in the used and aged materials. The ductile-brittle transition temperature of the aged material is lower than that of the used material indicating ductility of the used material recovers by the heat treatment. Rate of grainboundary fracture area to brittle fracture area of the used material is much larger than that of the aged material. Based on the Charpy impact test results in this and previous studies, change in embrittlement characteristic with operating time is discussed by introducing the matrix and the grainboundary strengths, and the plastic deformation resistance which determine the matrix and grainboundary fracture, and ductile fracture respectively.
  • M. Arif HAMDAM, Shigeru NAGAKI, Kenichi OSHITA, Shinya HANAMURE
    2016 年 65 巻 7 号 p. 532-537
    発行日: 2016/07/15
    公開日: 2016/07/20
    ジャーナル フリー
    In this study, experimental and numerical analysis of pearlitic transformation plasticity were performed in a three-point bending loading system. First the experiments were performed in bending and tensile-compressive loading systems with the same austenitization condition. The obtained pearlitic transformation plasticity coefficient for S45C steel was different for the each loading system. Therefore a new constitutive equation which called Drucker-Prager model was proposed to consider the relationship between tensile and compressive experimental results. This new model shows the dependence of hydrostatic stress. To evaluate the validity of this model, a three-point bending test was simulated with Abaqus Standard for both von Mises type and Drucker-Prager type models. The theory of phase transformation was coded in user subroutines for the each model. The simulation results (von Mises and Drucker-Prager) were compared with experimental results of tree-point bending system. The results show that the Drucker-Prager model is exactly match to the experimental results of bending test, but the results of von Mises model are different to the experimental results.
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