電弧爐還原碴製作混凝土可行性研究

Feasibility study of concrete made with electric arc furnace slag

黃慶慶(Hnin-Hnin Mon)

指導教授 ： 黃偉慶

國立中央大學/工學院/土木工程學系/碩士(2008年)

摘要

鹼活化爐石粉混凝土與卜特蘭水泥混凝土相較之下，具有較佳之的抗壓強度發展、耐久性及抵抗化學侵蝕能力等優點，但亦伴隨速凝、乾縮量過大及鹼質與粒料反應等負面效應。研究發現以鹼活化處理技術，將電弧爐還原碴加以活化後做為混凝土中之膠結料，可替代水泥拌製混凝土，提升還原碴之資源再利用性。
本研究主要以爐石粉取代部分還原碴方式，降低活化劑用量改善速凝及乾縮問題。另一方面設計28天目標強度為140~210 kgf/cm2之鹼活化還原碴混凝土，同時進行成本分析，最後對鹼活化還原碴漿體之抗硫酸鹽能力及高溫高濕度下之膨脹量加以探討。
研究結果顯示爐石粉取代還原碴量達50%時，活化劑之鹼模數比可由1.75降為0.75，含鹼當量由7%降為4%，同時改善了速凝及乾縮問題。鹼活化還原碴混凝土在鹼模數比0.75、含鹼當量4%時，抗壓強度能便達到28天目標強度，且強度隨齡期持續增強，90天時最高可達347 kgf/cm2。耐久性試驗方面雖具有較好的抗硫酸鹽能力，但因鹼量高發生鹼質與粒料反應之潛能較高，因此應避免使用具活性之粒料。

關鍵字

速凝 ； 鹼活化還原碴混凝土 ； 收縮

並列摘要

Several studies indicate that alkali-activated slag cements and
concretes present high mechanical strength and good performance in
chemical attack. However waterglass-activated slag mortars and
concretes show significantly higher shrinkage and shorter setting time
than ordinary Portland cement.
This study aims at reducing shrinkage and averting the rapid setting
by partly replacing blast furnace slag in alkali-activated electric arc
furnace reductive slag concrete. Also, concrete mix composition
for alkali-activated electric-arc furnace reductive slag cement concrete
with compressive strength of 140 kgf/cm2 to 210 kgf/cm2 at the age of
28 days are developed.
The dosage of alkaline activator was reduced form 7% to 4% (by
Na2O) and modulus was reduced from 1.75 to 0.75 when the replacement
of blast furnace slag was up to 50% of electric-arc furnace reductive slag.
When the dosage of alkaline activator decrease, the setting time increase
and longer than ordinary Portland cement. The drying shrinkage was been
reduced and the compressive strength of the concrete was found to be
over 210 kgf/cm2 at 28 days.

並列關鍵字

electric arc furnace reductive slag ； setting time

參考文獻

郭硯華，「以鹼活化技術資源化電弧爐煉鋼還原碴之研究」，國立中央大學土木工程研究所碩士學位論文（2007）。

ASTM C596 (2001). “Standard Test Method for Drying Shrinkage of Mortar Containing Hydraulic Cement.” ASTM Designation.

ASTM C191 (2004). “Standard Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle.” ASTM Designation.

ASTM C490 (2004). “Standard Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete .” ASTM Designation.

Bakharev, T., Sanjayan, J. G., and Cheng, Y. B. (1999). “Alkali activation of Australian slag cement. ” Cement and Concrete Research, 29 (1),113-120.