不同型態之CFB副產石灰應用於混凝土之研究

Use of various CFB ashes in concrete

陳冠宇(Guan-Yu Chen)

指導教授 ： 黃偉慶

國立中央大學/工學院/土木工程學系/碩士(2011年)

摘要

CFB副產石灰為循環式流體化床發電鍋爐(Circulating Fluidized Bed Boiler，簡稱CFB) 為避免高含硫量之石油焦作為燃料於高溫燃燒時產生硫氧化物過量排放，而以石灰石進行脫硫製程下產生之工業副產物，主要成分為無水石膏，依外觀及取得之位置不同而有粉狀(飛灰)與粒狀(床灰)之差異。
本研究係利用粉狀副產石灰做為激發水淬爐石粉卜作嵐活性之活化劑，應用於部分膠結材料中，透過長期取樣蒐集，建立其物理性質與活化膠結品質之資料，並透過統計方式記錄材料品質變異，此外，並試以添加燃煤飛灰作為替代膠結材料，取代爐石粉用量達到多元摻配與再利用之效益；另一方面，本研究針對以浸泡水化方式穩定堆積處理之水化副產石灰，為達到大量使用之目的，透過應用於混凝土之方式，進行配合設計與應用成效分析，探討可行性與適用性，達到副產石灰之最大再利用率。
研究成果顯示，各年份出廠粉狀副產石灰，在材料物理性質變異及活化爐石粉能力上均具有相當穩定之品質，而燃煤飛灰取代部分爐石粉後，膠結品質仍相當良好，但是具有凝結時間較長之疑慮；在水化副產石灰應用於取代細粒料時，由於高吸水率使拌合用水明顯提升，且過量使用時，對於抗壓強度與體積穩定性均有不良影響，但若以研磨方式處理並以少量取代細粒料(10~15%)下，則可有相當明顯之改善 ，並經混凝土試拌證實其成效良好。

關鍵字

CFB副產石灰 ； 抗壓強度 ； 體積穩定性

並列摘要

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. With different appearances and different collection ways, CFE ashes can be divided into fly ash and bed ash.
In this study, CFB fly ash is mixed with blast furnace slag to activate the pozzolanic reaction of slag such that the activated slag can be used as cementitious materials. Through continuous collection of CFB samples for testing of physical property and slag-activation capacity, the quality of the CFB ashes was carefully evaluated. And use the co-firing coal fly ash to replace some slag as the cementing material. In practice, CFB bed ash and fly ash were soaked in water for 24 hours, allowing hydration of the ashes to occur, before the ashes are stockpiled. And these ashes are termed hydrated CFB ash (HCFB). In order to apply HCFB to concrete mixes, laboratory evaluations were made to find the feasible proportioning methods.
Test results indicate that the CFB fly ash is a stable quality material in terms of the physical properties and activation capability on the pozzolanic reaction of slag. Partial replacement of the slag with coal fly ash in activating their pozzolanic activity is possible, but delayed mortar setting time is accompanied. And excessive use of HCFB in concrete could result in reduced compressive strength and volume instability. By grinding of HCFB to grain sizes passing #200 sieve and limiting the amount of HCFB in concrete to 10 to 15%, it is possible to use HCFB in concrete.

並列關鍵字

Volume stability and durability ； Compressive strength ； CFB ash

參考文獻

Hsu, H.M., Cheng, A., Chao, S.J., Huang, R., Cheng, T.c. and Lin, K.L. (2009), “Controlled Low-Strength Materials Containing Bottom Ash from Circulating Fluidized Bed Combustion,’’ International journal of pavement research and technology, 2, 250-256.

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吳岳澤，「污泥灰渣全資源化水泥砂漿之研究」，國立中央大學環境工程研究所碩士學位論文(2006)。

Fraay, A.L.A, J.M. Bijen, Y.M. De haan (1989), “The Reaction of Fly Ash in Concrete,” Cement and Concrete Research, 19, 235-246.

Li, D., Zhong F.,Guo, Q. and Lu, J. (2007), “Properties of flash hydrated and agglomerated particles of CFB fly ashes,” Fuel, 88, 215-220.