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Title |
A Fundamental Study to Develop Low-CO2·High-Insulation Lightweight Concrete Using Bottom Ash Aggregates and Air Foam
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Authors |
이광일(Kwang-Il Lee); 문주현(Ju-Hyun Mun); 박영식(Young-Shik Park); 양근혁( Keun-Hyeok Yang) |
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DOI |
https://doi.org/10.4334/JKCI.2019.31.3.221 |
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Keywords |
바텀애시 골재; 기포; 경량 콘크리트; 저탄소; 고단열 bottom ash aggregate; air form; lightweight concrete; low CO2; high insulation |
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Abstract |
The objective of the present study is to estimate the potential for developing lightweight concrete with low-CO2·high insulation properties to apply for precast insulation panel in building structures. For main binder and aggregates of such concrete, 30 % ordinary portland cement, 50 % ground granulated blast-furnace slag, 20 % fly ash by weight and bottom ash granules were used, respectively. To enhance the thermal resistance of concrete, air form was added up to 20 % of unit volume of concrete. Concrete specimens were cured under different temperature conditions as follows: 1) constant temperatures of 20 °C or ; 2) variable conditions including constant 20 °C beyond an early age of 10 hrs at 40 °C or 60 °C. The thermal conductivity of concrete specimens was estimated using the measured air-dry density and equation validated by Neville. The compressive strength gain model was proposed on the basis of the maturity concept to consider the producing process of precast panels. Test results showed that the air-dry density and compressive strength of the developed concrete were marginally affected by water-to-binder ratio and curing condition, whereas decreasing rates of 12 % in air-dry density and 64 % in compressive strength were observed when the foam volume ratio increased from 0 % to 15 %. The thermal conductivity of the developed concrete using bottom ash aggregates and 15 % air form by volume was estimated to be approximately 20 % lower than that of the conventional lightweight aggregate concrete. Considering the compressive strength required in precast concrete insulation panel, water ratio not exceeding 30 % and foam volume of 5~10 % could be recommended for low-CO2·high insulation precast panel using the materials attempted in the present study.
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