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小山 拓*; 上野 一貴*; 関根 麻里子*; 松本 吉弘*; 甲斐 哲也; 篠原 武尚; 飯倉 寛; 鈴木 裕士; 兼松 学*
Materials Research Proceedings, Vol.4, p.155 - 160, 2018/05
被引用回数：0 パーセンタイル：0.18(Materials Science, Characterization & Testing)We developed, in this study, a novel method to observe internal deformation of concrete by the neutron transmission imaging technique. In order to visualize the internal deformation of concrete, the cement paste markers containing Gd
O
powder were two-dimensionally dispersed around the ferritic deformed rebar in the reinforced concrete. This experiment was conducted using BL22, RADEN, in the Material and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. The transmission images of the reinforced concrete sample were taken at several positions on the vertical sample stage, and the displacement of the marker from the initial position was successfully evaluated within approximately 
0.1 mm accuracy by image analysis for selected markers with higher contrast and circularity. Furthermore, concrete deformation under pull-out loading to the embedded rebar was evaluated by the same way, and its reaction compressive deformation was successfully observed by analyzing the displacement of the markers. The results obtained in this study bring beneficial knowledge that the measurement accuracy of the marker displacement can be improved more by choosing a spherical shape of the marker and by increasing the contrast of the marker.
諸岡 聡; Gong, W.*; 相澤 一也; 川崎 卓郎; Harjo, S.
no journal, ,
Recently, a series of magnesium alloys containing a 18R Long-Period Stacking Ordered (LPSO) structure, have attracted considerable attention because they exhibit excellent mechanical properties, including high strength and reasonable ductility. To determine the plastic deformation behaviour of LPSO structure and the origin of the deformation mechanism are important for further materials development. In this study, deformation-kinking behavior of a Mg
Zn
Y
alloy was investigated by in-situ neutron diffraction during cyclic deformation. In-situ TOF neutron diffraction experiments during tension-compression and compression-tension cyclic loading at room temperature were performed by TAKUMI at MLF of J-PARC. The peak stress in the compression is larger than that of the tension, suggesting that quasi-twinning accompanying with hardening was occurred in compression deformation. On the other hand, results of individual (hkl) lattice strains in the loading direction show that, the (60.0) family grains in the loading direction accommodated a greater portion of elastic strain than that of the (00.18) family grains in the loading direction start accommodated less portion. This indicated that the latter started to yield prior to that of the former, causing the former to carry more applied load, i.e., intergranular stress. The large intergranular stresses generated with the progress of deformation, were speculated to accelerate the backward plastic flow that resulting in an increase of the Bauschinger stress and Bauschinger strain.
鈴木 裕士; 楠 浩一*; 兼松 学*; 向井 智久*
no journal, ,
Recently, the neutron diffraction technique has been provided to some applications on the structural engineering studies of the reinforced concrete structure. For example, we applied it to evaluation of the bond condition of the post installed adhesive anchor. The result showed that the stress distributions exhibit different trend depending on the type of adhesive, and the difference in the bond stress calculated by the slope of the stress distribution in the anchorage region is correlated to the difference in their bond strengths. The other topic is evaluation of bending bond behaviour of the reinforced concrete beam reinforced by main rebar and some stirrups. The stress distributions along main rebar as well as stirrups embedded in concrete were successfully measured using neutron diffraction under bending moment, and bond degradation due to flexural cracking was captured by measuring a change in the bond stress distribution. These results suggest that neutron diffraction can provide insight into the real structural engineering issues on the reinforced concrete structures.
