石炭灰とセメント混合率を調整した海砂代替材の化学組成評価  [in Japanese] EVALUATION ON CHANGE OF CHEMICAL COMPOSITION OF GRANULATED COAL ASH UTILIZED TO ALTERNATIVE SEA SAND IN COASTAL AREA  [in Japanese]

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Abstract

石炭灰と高炉セメントB種を混合し,造粒・固化した海砂代替材(石炭灰造粒物)がリサイクル材料として製造されている.港湾工事用のサンドコンパクション材や海域の覆砂材として活用され,その適用範囲が拡大されることにより循環型社会形成への寄与が期待される.海砂代替材は,石炭灰とセメントおよび水の化学反応により硬化しており,天然材料と異なり長期的な化学反応および,緩やかであるが海水中での浸漬に伴い組成物質が変化すると想定される.しかし,石炭灰とセメントの配合比率に基因する長期的な化学反応特性と海域で長期間浸漬した場合の経時的な組成変化は十分に明らかにされていない.本研究では,この海砂代替材の配合比率による化学組成の変化と海域で長期的に浸漬した後の組成物質の最終形態を明らかにした.

 Granulated coal ash is the alternative sea sand. That is manufactured by mixing coal fly ash powder with a small amount of cement and adequate amount of water. GCA consists of particles that ranged from coarse sand to gravel. The mean diameter of GCA is approximately 20mm. Moreover, the particles is a porous material which has a small specific gravity. It is expected that the environmental loads resulting from industrial wastes will be reduced if GCA was used. The purpose of this study is to evaluate of change of chemical composition of GCA utilized alternative sea sand in coastal area. At first, The five kinds of alternative sea sand in different mixing ratio of fly ash and cement were prepared. These materials were cured for 30 months prior to use in the experiments. The changes of the chemical composition of alternative sea sand were analyzed by XRF, XRD, and SEM observation. Moreover, the materials were analyzed to investigate the difference in specific surface by Gas Adsorption. Second, the standard GCA samples were immersed in sea water for three years. And, Divers collected the GCA layer sample which was used for 13 years in bottom sediment of coastal area. These sample materials were evaluated by XRF, XRD. From our findings, it is clarified that the change of the chemical composition of alternative sea sand, which was cured for 30 months and used for long term in coastal area.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 72(2), I_420-I_425, 2016

    Japan Society of Civil Engineers

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