• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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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.

• Computers and Concrete
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• 제31권4호
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• pp.315-325
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• 2023

Calcium leaching is one of the main deterioration factors in concrete structures contact with water, such as dams, water treatment structures, and radioactive waste structures. It causes a porous microstructure and may be coupled with various harmful factors resulting in mechanical degradation of concrete. Several numerical modeling studies focused on the calcium leaching depth prediction. However, these required a lot of cost and time for many experiments and analyses. This study presents an artificial neural network (ANN) approach to predict the leaching depth quickly and accurately. Totally 132 experimental data are collected for model training and validation. An optimal ANN model was proposed by ANN topology. Results indicate that the model can be applied to estimate the calcium leaching depth, showing the determination coefficient of 0.91. It might be used as a simulation tool for engineering problems focused on durability.

• 콘크리트학회논문집
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• 제20권1호
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• pp.77-88
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• 2008

본 논문에서는 염해를 받는 RC 구조물의 부식 내구성을 예측하기 위한 새로운 접근 방법을 제시한다. 이 예측 방법은, 현장 계측 데이터가 추가적으로 있을 때 베이스 정리 이론에 의하여 계속적으로 업데이팅을 할 수 있다. 모델 매개변수의 확률론적인 특성은 모델로 명백하게 고려된다. 염해 해석 모델의 절차를 간단하게 하기 위해서는, 내구성 한계의 확률은 라틴 하이퍼큐브 샘플 추출법에서 얻는 표본에서 결정된다. 이러한 새로운 방법은 중요한 콘크리트 구조물을 설계하기에 아주 유용하다. 그리고 모니터링을 통한 실 콘크리트구조물의 잔존수명을 예측 할 수 있다.

• 한국안전학회지
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• 제20권2호
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• pp.113-118
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• 2005

Recently, the corrosion of reinforced concrete structures has received great attention related with the deterioration of sea-side structures, such as new airport, bridges, and nuclear power plants. In this regards, many studies have been done on the chloride attack in concrete structures. The purpose of the present study is to explore the influences of chloride attack parameters to service life of reinforced concrete structures and to propose the rational program for the guarantee of service life. for this purpose, several codes for durability design have been examined and the diffusion analysis based on Fick's second law has been performed with various parameter value. The present study indicates that durability design code of Japan Society of Civil Engineers is more rational than other codes but the application of durability design code of JSCE to domestic durability design needs more studies to the various parameter values related with chloride penetration.

• 콘크리트학회논문집
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• 제19권5호
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• pp.585-593
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• 2007

본 연구에서는 해안 환경에 노출된 콘크리트 구조물의 내구성 평가에 대한 모델을 표면 염소이온농도 $(C_s)$의 시간에 대한 증가와 염소이온 확산계수 (D) 및 임계염소이온농토 $(C_{lim})$를 고려하여 제안하였다. 또한 콘크리트 구조물의 정밀한 내구수명 예측을 위하여 $C_s$와 D의 시간의존성이 고려되었으며, 시간에 따라 변화하는 $C_s$를 고려한 Fick의 제2법칙의 정밀해를 구하였다. $C_s$의 시간의존성에 대해서는, 기존 실험 결과를 바탕으로 시간에 대한 대수 함수 형태의 $C_s$ 모델을 제안하였으며, D의 시간의존성을 고려하기 위하여 구조물의 전체 노출 기간에 대한 시간의 평균값을 적용하였다. 또한 염해 환경 하에 있는 철도 구조물이 100년의 내구 수명을 보장할 수 있도록 하기 위해, 본 논문에서 제안된 모델과 시방서 기준에 근거하여 내구성 설계를 수행하였다. 제안된 모델은 유럽에서 널리 사용되고 있는 성능 중심의 설계 기법에 의해 검증되었으며, 이로부터 기존의 시방서 설계기준은 해안 환경에 노출된 콘크리트 구조물의 내구 성능을 과소 평가하여 매우 보수적인 설계결과를 유발하고 있음을 알 수 있다. $C_s$와 D의 시간의존성을 고려한 본 모델은 기존 시방기준의 이러한 문제점을 개선하여 염해를 받는 콘크리트 구조물의 내구수명을 정확하고 합리적으로 평가할 수 있을 것이다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.229-232
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• 2006

Most of sewage in our country has been made by concrete, and currently they shows gradual deterioration. One of serious problems happened in the sewage is a corrosion of sewage itself. Namely, biochemical corrosion is the most important one. Deterioration phenomenon in concrete used in sewage is occurred by environment condition of sewage, such as erosion by the acid, erosion by sulfate, corrosion by carbonation and so on several factors. However, at present, investigation data on durability of Kangnung city sewage is not sufficient. In addition, the prediction of repair time and selection of rehabilitation method is also not easy. Accordingly, in this research, investigation on durability of sewages located in Kangnung city was carried out. It will also supply the basic data for repair and rehabilitation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.269-272
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• 2006

Chloride ion diffusion is the most important thing of occuring deterioration in RC structure. So it is important to decide the precise chloride ion diffusion coefficient in order to predict the durability life in RC structure. The purpose of this study is to analyze the established data, which are restricted by chloride diffusion coefficient, and to calculate chloride ion diffusion coefficient using RCPT test. To examine the prediction of the concrete structure durability by an FEM analysis and the chloride diffusion coefficient as a variable. Each surface finishing materials were effective on the increment of chloride penetration resistance, but showed a little different effect depending on the type of surface finishing material.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.97-101
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• 2008

As the number of concrete building structures in marine environment increases, it is important to study and predict the durability and the compound deterioration of the concrete which is exposed in both chloride and freezing-thawing damage. The concrete's resistance against freezing and thawing is tested based on KS F 2456, while its chloride ion diffusion coefficient is evaluated based on NT BUILD 492. In result, the more exposure to freezing and thawing process, the shorter life it gets, due to the increased amount of chloride ion diffusion coefficient.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.334-338
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• 1995

In recent years, the prediction of the deterioration rate of concrete structures has become major research interest. However, there are still many uncertain factors in the deterioration process and the relation between deterioration and durability of structures. This is mainly due to various uncertainties involved in the construction process and the environmental conditions which affect the rate of deterioration of concrete structures. In this study a limit state model in terms of random crack width due to applied dead and live loads is proposed for the assessment of crack damage of reinforced concrete structures. The AFOSM reliability method is used for the reliability evaluation of the crack durability of concrete bridges. The proposed model for crack durability of concrete bridges is applied to the Seoul interior circuit elevated expressway. The sensitivity analyses are performed for the proposed model.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.465-466
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• 2010

In this paper, an integrated system is proposed which can evaluate both the early-age properties and durability performance of concrete structures. This integrated system starts with a hydration model which considers both Portland cement hydration and chemical reactions of supplementary cementing materials (SCM). Based on the degree of hydration of cement and mineral admixtures, the amount of reaction products, the early age heat evolution, chemically bound water, porosity, the early age short-term mechanical behaviors, shrinkage and early-age creep are evaluated as a function of curing age and curing conditions. Furthermore, the durability aspect, such as carbonation of blended concrete and chloride attack, are evaluated considering both the material properties and surrounding environments. The prediction results are verified through experimental results.