稻殼灰運用於混凝土之性質探討

The study of Rice Husk Ash Application in concrete

吳韋陞(Wei-Sheng Wu)

指導教授 ： 林利國

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2010年)

摘要

近些年來政府持續推動永續工程、節能減碳等相關議題，無疑就是希望能達到工程與環境生態相互平衡的願景；其中以營建產業最常使用的水泥最為耗能，平均每使用1公噸的水泥將會排放0.85公噸的二氧化碳，故本研究將運用廢棄物稻殼灰，當作卜作嵐材料(Pozzolanic Material)，取代部分水泥製成高性能混凝土。
本研究乃針對稻殼灰取代水泥添加於混凝土中進行性質探討，稻殼灰類型為廢棄物稻殼灰與使用稻殼進行高溫燒結(燒灰溫度為500℃、700℃與900℃)，水膠比選定W/B=0.24、0.3與0.4，取代水泥量為0%、5%、10%、20%與40%，並探討與分析其新拌、硬固、耐久與微觀等性質。稻殼灰於顯微鏡底下型態為孔窩結構狀，有別於其他卜作嵐材料，高保水、耐腐蝕與添加後產生緩凝皆為此之特性，經不同溫度燃燒形成之稻殼灰其二氧化矽含量皆達90%，此成分與水泥水化物氫氧化鈣結合形成之C-S-H膠體將填塞微孔隙，並有效提升混凝土水密性與抗壓強度；本研究發現研磨過後之稻殼灰因粒徑小、比表面積大與水泥水化反應良好，將有助於提升混凝土之各項性質；從X-Ray圖得知900℃稻殼灰結晶形態最為完全，將不利於卜作嵐反應；本研究建議最佳燒灰溫度為500℃。

關鍵字

卜作嵐材料 ； 稻殼灰 ； 孔窩結構 ； 節能減碳

並列摘要

In recent years the government continued to promote the sustainable engineering, energy saving and carbon reduction and other related issues, no doubt wish to achieve a balance between engineering and ecology of vision; which the construction industry, cement industry, the most frequently used in energy consumption, using an average 0.85 tonnes of cement will be tonnes of carbon dioxide emissions, this study will use waste rice husk ash as a pozzolanic material, to replace part of cement made of high performance concrete.
This study presents a research on blended concrete containing waste rice husk ash (RHA), in which residual RHA from electrical furnace in Vietnam and RHA produced by controlled incineration at 500℃, 700℃ and 900℃. Ordinary Portland cement is partially replaced with RHA at the dosages of 0%, 5%, 10%, 20% and 40% by weight of cement. The water to binder is kept at 0.24, 0.3 and 0.4 and the slump of concrete is maintained at 50-180 mm with the aid of superplasticizer. The properties of fresh and harden blended concrete were determined.
Test results showed that to producing useful rice husk ash, the rice husk should be burnt beyond 500℃. RHA will be change from amorphous forms to crystalline form of silica at 800℃. Incorporation of RHA in concrete resulted in increased water demand. Addition of waste ashes was related to a decrease in compressive strength and increase in water absorption. The pozzolanic reactivity of waste RHA improved when its particle size decreased. Increasing RHA fineness would enhance the strength of blended concrete. The pozzolanic reactivity of the amorphous ash (500℃ RHA,700℃ RHA) was higher than those found for crystalline ash, demonstrating the important effect of the crystallization degree when silicon dioxide reacts with portlandite.

並列關鍵字

Pozzolanic Material ； Rice Husk Ash ； Porous Cellular Structure ； Energy Saving & Carbon Reduction

參考文獻

[44] 劉正川，蘇欣宏，王亮力，「氧化矽與氧化鋯應用於混凝土強度之研究」，台北科技大學學報，第41期，2006，第115-122頁。

[45] 倪禮豐，稻殼再利用技術，「花蓮區農業專訊」，第61 期，2007，第19-20頁。

[1] P. K. Metha and D. Pirtz, “Use of Rice Husk Ash to reduce temperature in High Strength Mass Concrete,” ACI Journal, 1978, pp.60-63.

[4] M.N. AI-Khalaf, “Development of microstructure & other properties in Rice Husk Ash-OPC systems,” 1984.

[11] M.N. AI-Khalaf and H.A. Yousift, “Use of rice husk ash in concrete,” 1984.