• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.700-703
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• 2000

With respect to durability, the impotance of carbonation lies in the fact that it reduces the pH on the pore water in hardened concrete. However, the carbonation velocity is effected by the water/cement ratio, materials, unit cement weight, porosity, kinds of finishing materials, accuracy of constructing, environmental factors and so on. And the air permeability is closely related to the carbonation velocity because it represents the properties of concrete. This paper presents an experimental investigation on the carbonation effected by air permeability n mortar and concrete. As a result, it was found that the carbonation velocity of concrete is faster than that of mortar and it is possible to predict the carbonation velocity using air permeability.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술.기술논문발표회
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• pp.41-44
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• 2004

Recently, in the case of domestic, for all that the deterioration environment about the carbonation of reinforced concrete structures is accelerated, systematic diagnosis and researches are not completed. And the selection techniques of repair material and method used under the situation that the indicator and the performance evaluation method are nor established are dependant on existing experience. Therefore, the purpose of this study is intend to present fundamental data for the reasonable selection of repair material and method. durability design and longevity on the deteriorated reinforced concrete structures, through computing the carbonation depth and velocity coefficient by accelerating carbonation test under various accelerating conditions and investigating the application of carbonation evaluation method. The results of this study are as follow; The resistances to carbonation are increased when the W/C ratio if lower and the treatment of surface coating is executed. And the carbonation depth and velocity coefficient according to accelerating carbonation test conditions are increased when the conditions of temperature, relative humidity and $CO_2$density are higher individually.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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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.

• 한국구조물진단유지관리공학회 논문집
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• 제12권2호
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• pp.163-170
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• 2008

탄산화속도는 구조물이 위치한 환경의 이산화탄소($CO_2$) 농도, 콘크리트 품질, 구조물의 형상 등에 의해 영향을 받게 되며, 본 연구에서는 국내의 내구성 조사자료를 토대로 하여 콘크리트 품질에 따른 각종 인자를 고려한 탄산화속도계수 추정식을 도출하고자 수행되었다. 수행결과, 도심지역이 산간지역에 비해 교량의 경우 약 1.5배, 터널의 경우 2.5배 탄산화가 빠르게 진행되는 것으로 분석되었으며, 도심지역에서는 건축물, 터널, 교량의 순서로 교량에 비해 약 2.7배, 1.3배 탄산화가 빠르게 진행되는 것으로 평가되었다. 산간지역에서는 교량이 터널보다 약 1.3배 빠르게 진행되는 것으로 평가되었으며, 도심지역에서 교량의 상부구조가 하부구조보다 약 1.3배 빠르게 진행되는 것으로 분석되었다. 한편 압축강도를 물 시멘트비로 환산하여 일반적으로 적용하고 있는 기존의 일본 기시타니식 탄산화속도계수 추정식과 비교한 결과 대부분이 기시타니식보다 빠른 것으로 평가되었다.

• 한국구조물진단유지관리공학회 논문집
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• 제23권1호
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• pp.122-129
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• 2019

콘크리트에서 염소 이온과 같은 열화물질의 이동은 응력상태 및 재령의 증가에 기인한 공극구조에 따라 변화한다. 본 연구에서는 재령 28일, 91일, 그리고 365일 양생된 OPC 콘크리트의 압축 및 인장 하중조건을 고려하여 촉진탄산화 실험을 실시하였으며, 탄산화 거동을 평가하였다. KS F 2584에 의거하여 탄산화 속도계수를 도출하였는데, 하중을 고려하지 않을 경우 탄산화 속도계수는 재령 28일 대비 재령 91일은 50.0 % 수준으로, 재령 365일에서는 44.8 % 수준으로 감소하였다. 28일 재령 시, 하중의 영향으로 인해 인장재하영역에서는 103.9 ~ 108.8 % 수준으로 압축재하영역에서는 91.9 ~ 104.6 % 수준으로 변화하였다. 재령이 증가함에 따라 탄산화 속도는 크게 감소하였는데, 30 % 인장재하영역에서는 탄산화 속도계수가 1년 경과시 47.3 % 수준으로, 60 % 인장재하영역에서는 52.5 % 수준으로 감소하였으며 30 % 압축재하영역에서는 45.8 %로, 60 % 압축재하영역에서는 44.9 % 수준으로 감소하였다. 압축재하영역 30 %에서는 공극압밀로 인해 탄산화 속도계수가 감소하였으나 하중의 증가에 따라 압축재하영역 60 %에서는 미세균열의 영향으로 탄산화 속도계수가 증가하였다. 또한 인장재하영역은 압축부와는 다르게 탄산화 속도계수가 선형적으로 증가하는 경향을 나타내었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.62-65
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• 2003

In this study, to confirm corrosion of reinforced concrete affected by carbonation, chloride ion diffusion, absorption ratio, air permeability, measured carbonation velocity coefficient, chloride ion diffusion coefficient, absorption coefficient, air permeability coefficient. Corrosion velocity under environment of complex deterioration. And than compared corrosion velocity with these coefficients. As the results of this study, the correlation coefficient between chloride ion diffusion coefficients and absorption coefficient was revealed that it is very high. As well, an increase in carbonation, chloride ion diffusion also increases corrosion velocity. It showed that corrosion velocity was affected by the carbonation, chloride ion diffusion, absorption ratio, air permeability. Generally, data on the development of these coefficient made with none, organic B, organic A, inorganic B, and inorganic A is shown. It showed that coating of surface prevent steel bar from deteriorating.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.403-408
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• 2000

Hardened concrete contains pores of varying types and sizes, and therefore the transport of air through concrete can be considered. The rate of permeability will not only depend on the continuity of pores, but also on the moisture contents in concrete. In this paper, the effects of curing conditions and moisture content ratios on the carbonation and air permeability are investigated according to the accelerated carbonation test. The results are follows. 1) Compressive strength, carbonation velocity and air permeability are influenced by the moisture content and curing method. 2) The relationship between carbonation velocity coefficient and air permeability coefficient has been quite well established.

• Structural Engineering and Mechanics
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• 제89권3호
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• pp.301-308
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• 2024

Concrete carbonation is a continuous and slow process from the outside to the inside, in which its penetration slows down with the increased depth of carbonation. In this paper, the results of the evaluation of the measurement of concrete carbonation depth using a non-destructive ultrasonic testing method are presented. According to the results, the relative nonlinear parameter caused more sensitivity in carbonation changes compared to Rayleigh's fuzzy velocity. Thus, the acoustic nonlinear parameter is expected to be applied as a quantitative index to recognize carbonation effects. In this research, combo diagrams were developed based on the results of ultrasonic testing and the experiment to determine carbonation depth using a phenolphthalein solution, which could be considered as instructions in the projects involving non-destructive ultrasonic test methods. The minimum and maximum accuracy of this method were 89% and 97%, respectively, which is a reasonable range for operational projects. From the analysis performed, some useful expressions are found by applying the regression analysis for the nonlinearity index and the carbonation penetration depth values as a guideline.

• 콘크리트학회논문집
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• 제13권3호
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• pp.277-284
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• 2001

경화콘크리트는 골재와 시멘트 수화물에 의한 매트릭스 구조로 되어진 다공체이기 때문에 내부에 다양한 크기와 형태의 공극을 갖으며, 공기투과성을 갖게 된다. 이러한 투기성능은 탄산가스의 침투.확산에 따른 중성화속도와 산소와 물의 침투에 따른 철근의 부식속도를 결정하게 되어 철근콘크리트 구조물의 내구성과 밀접한 관련이 있는 것으로 보고되고 있다. 한편, 중성화속도 및 투기성능은 표면 마감재 및 콘크리트의 함수율에 의해 크게 영향을 받게 된다. 이에 본 연구는 물-시멘트비 및 마감재의 종류, 양생조건이 콘크리트의 중성화속도 및 투기성에 미치는 영향을 검토하고, 양생조건에 따른 함수상태가 투기성에 미치는 영향을 검토하였다. 본 실험결과 중성화속도 및 투기성은 물-시멘트비, 마감재의 유무 및 종류, 양생조건에 의해 크게 영향을 받으며, 콘크리트의 투기계수는 중성화속도계수와 밀접한 관련이 있는 것으로 나타나, 향후 중성화속도를 평가함에 있어서 투기계수를 요인으로 추정 가능할 것으로 사료된다.

• 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.