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Title |
Mechanism of Strength Development in Ultra High Strength Concrete Using the Electric Arc Furnace Oxidizing Slag as Fine Aggregate
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DOI |
https://doi.org/10.4334/JKCI.2013.25.1.003 |
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Keywords |
초고강도 콘크리트 ; 강도발현기구 ; 잔골재 ; 전기로 산화 슬래그 ; 세척사 ultra high strength concrete ; mechanism of strength development ; fine aggregate ; electric arc furnace oxidizing slag ; sea sand |
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Abstract |
In ultra high strength concrete, when electric arc furnace oxidizing slag is substituted for sea sand as fine aggregate, compressive strength was improved about 15 MPa. To figure out the cause of the improvement in compressive strength, this study considered the dissolution characteristics of Ca component in fine aggregate and examined the microstructure, porosity, microhardness, and Ca/Si mole ratio on the interface of fine aggregate and paste. And to examine the mechanism of strength improvement resulted from the shape of fine aggregate, this study measured the surface roughness of fine aggregate with AFM. According to the result of this experiment, the mechanisms of strength improvement in ultra high strength concrete resulted from the use of electric arc furnace oxidizing slag as fine aggregate can be divided into chemical and physical mechanisms. In the chemical mechanism, the soluble Ca component contained in electric arc furnace oxidizing slag is dissolved and forms a hydrate between fine aggregate and paste to improve the interlocking strength of fine aggregate-paste. Also, it makes the microstructure around the fine aggregate. And in the physical mechanism, electric arc furnace oxidizing slag has a twice greater surface roughness than sea sand, so the interlocking strength between fine aggregate and paste increases, which contributes to the development of compressive strength.
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