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Title |
The Prediction Model of Carbonation Process by CO2 Diffusion Using the Air Permeability Coefficient for Concrete
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Keywords |
탄산화 ; 예측모델 ; 이산화탄소 확산 ; 투기계수 ; 수산화칼슘 carbonation ; prediction model ; CO2 diffusion ; air permeability coefficient ; Ca(OH)2 |
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Abstract |
Recently, some mathematical models for the prediction on progress of carbonation of concrete were reported. These models take account for CO2 diffusion and chemical reaction between Ca(OH)2 and CO2. Based on the assumption that CO2 diffuses in the carbonation zone and reacts with Ca(OH)2 at the outer face of carbonation zone and non-carbonation zone. In this study, a mathematical model to predict the progress of carbonation of concrete has been established based on the reducing concentration of Ca(OH)2 in the carbonation progress zone, where Ca(OH)2 reacts with CO2 and Ca(OH)2 and CaCO3 coexist. Also, the prediction model of carbonation progress rate of concrete using the air permeability coefficient regarding to CO2 diffusion is developed. As a result of this study, an expression, the model equation is obtained for the prediction of carbonation based on the time and interaction velocity between CO2 and Ca(OH)2 dependent air permeability coefficient. The prediction by the model satisfied the experimental data of the accelerated carbonation for painted concrete. Consequently, the model can predict the rate of carbonation and the potential service life of concrete structure exposed to atmosphere.
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