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論文 |
論文
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島居, 和之 ; 川村, 満紀 ; 枷場, 重正 ; 五十嵐, 心一
概要:
金沢大学理工研究域環境デザイン学系<br />Recently, the basic oxygen furnace slag produced in a new steel-making process aiming at energy a
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nd resource saving is being as fine particles under 5 mm size because it breaks down itself due to its high content of f-CaO. In future, this type of basic oxygen furnace slag is anticipated to replace the conventional basic oxygen furnace slag. The objective of this study was to the applicability of this powdered basic oxygen furnace slag as a subbase material. Firstly, the changes in physical and chemical properties, the surface texture and the hydrated products of the basic oxygen furnace slag naturally weathered outdoors were determined by X-ray diffraction, differential thermal analysis (DTA) and SEM-EDXA analysis. Secondly, the strength test, the CBR test and the expansion test of the compacted basic oxygen furnace slag mixtures were carried out in order to clarify the strength characteristics of the powdered basic oxygen furnace slag as a subbase material and the effect of weathering outdoors on reducing its unfavorable self-deterious properties. The main results obtained are summarized as follows; (1) The major compounds of the powdered basic oxygen furnace slag were β-C_2S, C_2F, C_2S-C_3P, Wustite and a considerably large amount of f-Cao and Ca(OH)_2. (2) In the powdered basic oxygen furnace slag naturally weathered outdoors, the hydration of β-C_2S and f-Cao slowly progressed with age, resulting in the formation of C-S-H gel, Ca(OH)_2 and CaCO_3 on the surface of particles. (3) The powdered basic oxygen furnace slag became a stable material not showing self-deterious property by weathering outdoors for about three months, and thus it can be used as a subbase material.
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| 2.
論文 |
論文
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久保, ホベルト洋 ; 五十嵐, 心一 ; 川村, 満紀
概要:
This paper investigated the volume changes of high strength mortars cured in water. The effects of characteristic microstructure on the volume stability were considered in relation to the formation of microcracks. The results indicated
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that mortars without silica fume exhibited continuous swelling for long ages and the ones with silica fume shrank for a certain period after immersed in water, but started to swell at long ages. Cracking at long ages was confirmed for mortars with and without silica fume. However, there were distinct differences in the characteristics of crack pattern, such as the situation for cracking and their effects on the strength development between both. It was suggested that a mechanism other than autogenous shrinkage was involved in the volume changes that occurred in mortar with an extremely low water/binder ratio. Generation of internal expansive pressure due to the late cement hydration should be taken into account in the mechanism that cause microcracks in mortars at long ages.<br />Ex post facto report
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