CFB副產石灰為混凝土膠結材料之配比與特性研究; CFB ashes replace the cementing material in concrete for property and mix design research.

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Title:	CFB副產石灰為混凝土膠結材料之配比與特性研究;CFB ashes replace the cementing material in concrete for property and mix design research.
Authors:	王昱智;Yu-chih Wang
Contributors:	土木工程研究所
Keywords:	鈣礬石;循環式流體化床鍋爐;石油焦;Ettringite;Circulating Fluidized Bed Boiler;Petroleum Coke
Date:	2008-07-03
Issue Date:	2009-09-18 17:25:02 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	高溫循環式流體化床發電鍋爐(Circulating Fluidized Bed Boiler，簡稱CFB)以燃燒石油焦來發電，為避免燃燒高含硫量之石油焦產生硫氧化物之過量排放，故混合石灰石進行脫硫，所產生之副產物，即CFB副產石灰。本研究係利用CFB副產石灰具有自我膠結的能力，與水淬爐石粉及卜特蘭水泥混合製成膠結材料，並尋求最佳配比，取代部份的水泥材料，初始能運用於非結構混凝土，以達資源化再利用之目的。 CFB副產石灰依鍋爐內取樣位置不同分成CFB飛灰、床灰、水化灰，皆具有顆粒細小含石膏之特性。研究結果得知，CFB飛灰可與水泥反應產生水化反應，生成鈣礬石，且可對爐石粉產生活化效應而強化其卜作嵐反應，故應用於水泥-爐石粉系統中兼具膠結性及活化劑之功能；CFB飛灰與水泥及爐石粉混合使用時，如CFB飛灰用量不足，漿體晚期強度發展較差，而CFB飛灰用量超過30%時，則漿體早晚期強度會較低，故CFB飛灰使用於水泥-爐石粉系統中存有最佳用量範圍，約在18-22%間。在混凝土試拌方面，參考強度210 kgf/cm2及280 kgf/cm2之配比，在強度方面皆能達到要求。此外，比較CFB飛灰、床灰及水化灰之膠結成效得知，CFB飛灰優於床灰及水化灰。故將CFB飛灰應用於水泥-爐石粉系統中，兼具膠結性及活化劑之功能，顯示CFB飛灰為極具潛力之資源化副產品。 Circulating Fluidized Bed (CFB) Boiler is a means of energy-generating process by burning petroleum coke. In order to avoid blazed petroleum coke with high sulfur content from emitting overdosed sulfur dioxide, limestone is introduced in the boiler for desulfuration. The residue collected from the boiler is called CFB ashes. In this study, the activating/cementing characteristics of CFB ashes is investigated by blending with granulated blast furnace slag and portland cement. It is intended that CFB ashes can be used in concrete and a method for proportioning CFB ash in concrete can be developed. In accordance with different boiler position, CFB ashes can be classified as fly ash and bed ash, and both have similar chemical compositions, with high contents of gypsum and calcium oxide. The results show that CFB fly ash can react with cement to produce hydration products such as ettringite, and bring the activation of granulated blast furnace slag. It is considered that the CFB ash will act as both cementing material and activator in the cement-granulated blast furnace slag system concurrently. There is an optimum content of CFB ash in the cement/granulated blast furnace slag mixes. The paste strength could be low at later ages, if the CFB fly ash content is too low. Whereas, if the CFB fly ash content is over 30%, the paste strength will be low at the early age. Therefore, it is concluded that the cement-granulated blast furnace slag system will show best performance at the CFB fly ash content between 18% and 22%. Through proper mix design procedure, mixes containing as less as 20% cement are able to produce concrete with compressive strengths of 210 kgf/cm2 and 280 kgf/cm2, with the addition of 20% CFB fly ash. Besides, using the CFB fly ash in the cement-granulated blast furnace slag system not only improves the cementitious property but also activates the pozzolanic capability of slag. Thus CFB fly ash has been demonstrated to show very good potential in concrete.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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