• Title/Summary/Keyword: 탄산화 진행 예측

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Predicting Carbonation Progress of Carbonation Repaired RC Structures Repair (탄산화가 진행된 기존 RC구조물의 보수 공법 적용 후 탄산화 진행 예측)

  • Lee, Hyung-Min;Lee, Han-Seung
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.3
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    • pp.235-243
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    • 2017
  • Carbonation of concrete is being occurred due to interaction of atmospheric carbon dioxide with hydroxides. Reinforce concrete (RC) structure is getting collapse or accident due to corrosion of embedded steel rebar. The maintenance of reinforced concrete structure recently has the attention of researchers regarding durability of structure and its importance day by day is increasing. In order to study the carbonation progress of pre-repaired concrete, present study was carried out to measure the carbonation velocity for different repair materials up to 100% of carbonation. The obtained results have predicted the carbonation progress of repair materials in service condition. These results have been verified by FEM and FDM analysis. As a result, the carbonation depth can be predicted by using the carbonation prediction formula after the repair, and the analytical and the experimental values are almost similar when the initial $Ca(OH)_2$ concentration is assumed to be 40%.

The Prediction Model of Carbonation Process by CO2 Diffusion Using the Air Permeability Coefficient for Concrete (콘크리트의 투기계수를 이용한 CO2확산 탄산화진행 예측모델)

  • Kang, Suk-Pyo;Kim, Young-Sun;Song, Ha-Won;Kim, Gyu-Yong
    • Journal of the Korea Concrete Institute
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    • v.22 no.2
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    • pp.209-217
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    • 2010
  • Recently, some mathematical models for the prediction on progress of carbonation of concrete were reported. These models take account for $CO_2$ diffusion and chemical reaction between $Ca(OH)_2$ and $CO_2$. Based on the assumption that $CO_2$ 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 $CO_2$ and $Ca(OH)_2$ and $CaCO_3$ coexist. Also, the prediction model of carbonation progress rate of concrete using the air permeability coefficient regarding to $CO_2$ 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 $CO_2$ 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.

Durability Analysis and Development of Probability-Based Carbonation Prediction Model in Concrete Structure (콘크리트 구조물의 확률론적 탄산화 예측 모델 개발 및 내구성 해석)

  • Jung, Hyunjun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.4A
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    • pp.343-352
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    • 2010
  • Recently, many researchers have been carried out to estimate more controlled service life and long-term performance of carbonated concrete structures. Durability analysis and design based on probability have been induced to new concrete structures for design. This paper provides a carbonation prediction model based on the Fick's 1st law of diffusion using statistic data of carbonated concrete structures and the probabilistic analysis of the durability performance has been carried out by using a Bayes' theorem. The influence of concerned design parameters such as $CO_2$ diffusion coefficient, atmospheric $CO_2$ concentration, absorption quantity of $CO_2$ and the degree of hydration was investigated. Using a monitoring data, this model which was based on probabilistic approach was predicted a carbonation depth and a remaining service life at a variety of environmental concrete structures. Form the result, the application method using a realistic carbonation prediction model can be to estimate erosion-open-time, controlled durability and to determine a making decision for suitable repair and maintenance of carbonated concrete structures.

A Study on Predicting Progress Carbonation After Concrete Structures Repair (콘크리트 구조물 보수후 탄산화 진행 예측 평가 방법 연구)

  • Lee, Hyung-Min;Lee, Han-seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.11a
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    • pp.64-65
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    • 2013
  • Recently, people are concerned about how to maintain structure well because of safety. For effective maintenance of the structure, it should be resolved about carbonation, Durability, and Service Life issues. Solving that problem will Increase Safety of Structure. The carbonation velocity is produced an effect on carbon dioxide density of surrounding near structures, the concrete quality Therefore, This study compares the Velocity of carbonation due to maintenance of the structure. Also, this study will find Service Life of Concrete Structure through Predicting Carbonation Depth.

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A Study on Probability Carbonation Progress of Concrete After Repair Method of Carbonated RC Structures (탄산화가 진행된 기존 RC구조물의 보수공법 적용후 탄산화 진행 예측에 관한 확률론적 연구)

  • Lee, Hyung-Min;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.10a
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    • pp.41-42
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    • 2016
  • As the importance of maintenance of reinforced concrete structure recently has emerged, the attention of durability of structure has been increasing. There are many studies about durability decline especially due to the carbonation. In order to study carbonation progress after surface repair of carbonated concrete, each carbonation penetration velocity from different repair materials of concrete structure is compared through the experiment of carbonation accelerating CO2 concentration to 20% and 100%. As carbonation infiltration progress is predicted through this study, the counterplan of service life evaluation will be prepared on selection of repair materials of concrete structure.

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A Study on Predicting Progress Carbonation using FDM Analysis After Carbonated RC Structures Surface Repair (탄산화가 진행된 기존 RC구조물의 표면보수공법 적용 후 FDM 해석을 이용한 탄산화 진행 예측 연구)

  • Lee, Hyung-Min;Lee, Han-Seung;Kim, Yeung-Kwan
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.11a
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    • pp.13-14
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    • 2015
  • Carbonation is the results of the interaction of carbon dioxide gas in the atmosphere with the alkaline hydroxides in the concrete. in other words, of the hydrates in the cement pastes, the one which reacts with readily is Ca(OH)2, the product of the reaction being CaCO3 and which decreases the alkalinity of concrete. Consequently, RC structure is deteriorated due to steel corrosion in concrete. As the importance of maintenance of reinforced concrete structure recently has emerged, the attention of durability of structure has been increasing. There are many studies about durability decline especially due to the carbonation. In order to study carbonation progress after surface repair of carbonated concrete, each carbonation penetration velocity from different repair materials of concrete structure is compared through the experiment of carbonation accelerating CO2 concentration to 100%. As carbonation infiltration progress is predicted through this study, the counterplan of service life evaluation will be prepared on selection of repair materials of concrete structure.

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A Study on probability of rebar corrosion After repair method of carbonated existing RC structures (탄산화가 진행된 기존 RC구조물의 보수공법 적용후 철근의 부식확률 평가에 관한 연구)

  • Lee, Hyung-Min;Kim, Sang-Youl;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.32-33
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    • 2015
  • As the importance of maintenance of reinforced concrete structure recently has emerged, the attention of durability of structure has been increasing. There are many studies about durability decline especially due to the carbonation. In order to study carbonation progress after surface repair of carbonated concrete, each carbonation penetration velocity from different repair materials of concrete structure is compared through the experiment of carbonation accelerating CO2 concentration to 100%. As carbonation infiltration progress is predicted through this study, the counterplan of service life evaluation will be prepared on selection of repair materials of concrete structure.

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The Prediction model of Carbonation Process Using the Air Permeability Coefficient for Concrete (콘크리트의 투기계수를 이용한 중성화진행 예측모델)

  • Lim, Chang-Hyuck;Kim, Gyu-Yong;Lee, Tae-Gyu;Lee, Eui-Bae;Didolkar, Rahul B.;Kang, Suk-Pyo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.221-222
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    • 2010
  • In this study an expression is obtained the model equation for the prediction of carbonation based on the time and interaction velocity between $CO_2$ and $Ca(OH)_2$ diffusion coefficient.

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A Fundamental Study on the Prediction of Carbonation Progress Using Deep Learning Algorithm Considering Mixing Factors (배합인자를 고려한 딥러닝 알고리즘 기반 탄산화 진행 예측에 관한 기초적 연구)

  • Jung, Do-Hyun;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.30-31
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    • 2019
  • Carbonation of the root concrete reduces the durability of the reinforced concrete, and it is important to check the carbonation resistance of the concrete to ensure the durability of the reinforced concrete structure. In this study, a basic study on the prediction of carbonation progress was conducted by considering the mixing conditions of concrete using deep learning algorithm during the theory of artificial neural network theory. The data used in the experiment used values that converted the carbonation velocity coefficient obtained from the mixing conditions of concrete and the accelerated carbonation experiment into the actual environment. The analysis shows that the error rate of the deep learning model according to the Hidden Layer is the best for the model using five layers, and based on the five Hidden layers, we want to verify the predicted performance of the carbonation speed coefficient of the carbonation test specimen in which the exposure experiment took place in the real environment.

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A Fundamental Study on the Effect of Activation Function in Predicting Carbonation Progress Using Deep Learning Algorithm (딥러닝 알고리즘 기반 탄산화 진행 예측에서 활성화 함수 적용에 관한 기초적 연구)

  • Jung, Do-Hyun;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.60-61
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    • 2019
  • Concrete carbonation is one of the factors that reduce the durability of concrete. In modern times, due to industrialization, the carbon dioxide concentration in the atmosphere is increasing, and the impact of carbonation is increasing. So, it is important to understand the carbonation resistance according to the concrete compounding to secure the concrete durability life. In this study, we want to predict the concrete carbonation velocity coefficient, which is an indicator of the carbonation resistance of concrete, through the deep learning algorithm, and to find the activation function suitable for the prediction of carbonation rate coefficient as a process to determine the learning accuracy through the deep learning algorithm. In the scope of this study, using the ReLU function showed better accuracy than using other activation functions.

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