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Maruyama, Makoto*; Toriihara, Makoto*; Mikami, Tetsuji*; Hata, Koji*
JNC TJ7400 2005-030, 106 Pages, 2003/02
no abstracts in English
Iriya, Keishiro*; Mikami, Tetsuji*; Takeda, Nobufumi*; Akiyoshi, Kenji*
JNC TJ5400 2003-002, 104 Pages, 2003/02
The Horonobe underground research laboratory project doesn't carry on only safety assessment study but also demonstration of construction technique upon nuclear waste repositories. Low alkalinity cement is one of candidates for engineered barrier in order to prevent alteration of bentonite and rock by hyper alkaline solution. JNC has developed low alkalinity cement (HFSC) which contains a lot of fly ash, and has studied the physical and chemical properties by laboratory test.Effect on variety of quality of fly ash and monitoring corrosion of rebars in off-shore condition has been studied. In-situ test for actual use of HFSC in constructing the facility was planned. The results are summarized as below. Effects of variety of fly ash upon lower pH are relatively small by testing two type of fly ash and several fly ash content. Variety of fly ash effects properties of fresh concrete but its effect is not significant. And it little effects on mechanical behavior. However, it doesn't effect on properties of shotcrete. Although rebars corrode in HFSC in spite of no intrusion of chloride, increment of corrosion is not significant in half a year until a year. Applicability for structural members is demonstrated by loading test of tunnel concrete segments of HSFC. Pre-mixed HFSC can be supplied by mixing fly ash and silica fume in Sapporo and carry to Horonobe by cement truck.
Iriya, Keishiro*; Mikami, Tetsuji*; Akiyoshi, Kenji*; Uegaki, Yoshiaki*
JNC TJ8400 2002-013, 87 Pages, 2002/02
The underground research laboratory, which will be constructed in Horonobe, plays a role of demonstration of construction technique upon nuclear waste repositories. Low alkalinity cement is one of candidates for repositories as a cementitious material in order to prevent alteration of bentonite and rock by hyper alkaline solution. JNC has developed a low alkalinity cement (HFSC) which contains a lot of fly ash, and has studied the physical and chemical properties by laboratory test. However workability which is required for construction procedure of repositories has not been studied enough yet. This study shows if requirements in actual construction, such as shotcreting, self-compacting, and, grouting, are fulfilled, and if the workability is preferable for tunneling construction. It is demonstrated that HFSC is applicable for shotcreting by testing in a modeled tunnel. It is pointed out that re-bars have a possibility of corrosion in low alkalinity cement. In-site test for saline water which may accelerate corrosion is started by setting specimen made in last year. Analyzing and assessing will be done next year. Construction method of tunnel lining is investigated in case of applying pre-cast segments. Self-compacting concrete is adopted, since added silica-fume needs superplasticizer and its workability is very flowable. Two piece of segment were made for the section which designed for a ordinary urban tunnel. It is noted that pre-casting concrete can be made by HFSC. Super fine cement powder for grouting which indicate low alkalinity can be selected by combination of grinned lime stone powder and silica fume with grinned ordinary Portland cement. The items to be improved toward using in Horonobe construction are pointed out by results of this study and summarized a study plan is described. Major problem to be solved is delaying compressive strength generation of HFSC. It is recognized in shotcrete and self-compacting concrete. Selecting types of fly ash and ...
Iriya, Keishiro*; Mikami, Tetsuji*; *; Uegaki, Yoshiaki*
JNC TJ1400 2001-004, 150 Pages, 2001/05
no abstracts in English
Sugihara, Yutaka*; Utsugida, Yoshizo*; Mikami, Tetsuji*; Sawauchi, Y.*
PNC TJ1449 92-002, 81 Pages, 1992/02
no abstracts in English
Mikami, Tetsuji*; Sawauchi, Y.*; Utsugida, Yoshizo*; Yoshida, Kenji*; Shimabe, Kenichiro*
PNC TJ1449 91-012, 125 Pages, 1991/03
None
Mikami, Tetsuji*; Sawauchi, Y.*; Utsugida, Yoshizo*; Yoshida, Kenji*; Shimabe, Kenichiro*
PNC TJ1449 91-003, 26 Pages, 1991/03
None
Sugihara, Yutaka*; Mikami, Tetsuji*; Sawauchi, Y.*; Utsugida, Yoshizo*; Shimabe, Kenichiro*
JNC TJ1400 2005-019, 919 Pages, 1991/03
*; Sugihara, Yutaka*; Mikami, Tetsuji*; Shimabe, Kenichiro*
PNC TJ4449 90-002VOL1, 71 Pages, 1990/03
None
Ito, K.*; Kamemura, Katsumi*; Homma, N.*; Mikami, Tetsuji*; Aoki, Kenji*; Ishi, S.*
PNC TJ4449 89-003VOL2, 122 Pages, 1989/03
None
Ito, K.*; Kamemura, Katsumi*; Homma, N.*; Mikami, Tetsuji*; Aoki, Kenji*; Ishi, S.*
PNC TJ4449 89-003VOL1, 223 Pages, 1989/03
None
Tanaka, Hisaki*; Toyoshima, Yoshiyuki*; Akagawa, Takumi*; Yamazaki, Tatsuo*; Ura, Tetsuji*; Iwashita, Kazuhiro*; Mikami, Shigeaki*; Sato, Katsuya; Narumi, Issei
no journal, ,
no abstracts in English