• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.259-260
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• 2009

대부분의 콘크리트 구조물은 탄산화 및 염소이온의 침투에 의하여 철근부식을 겪고 있으나, 대다수의 콘크리트 구조물은 염소이온과 탄산화로 인한 복합열화를 겪고 있음에도 불구하고, 대다수의 연구들은 단일열화만을 다루고 있다. 본 연구는 탄산화로 인하여 탈착된 염소이온의 재확산을 추정하기 위한 접근방법을 개발하고 하였다. 이는 탄산화와 염소이온의 복합열화에 대한 성공적인 모델을 정립하는데 핵심적인 요소이다. 본 연구결과는 향후 복합열화 모델식에 반영되어 염소이온의 탈락으로 인해 탄산화 경계영역에서 염소이온의 농축 및 재확산을 효과적으로 표현할 수 있을 것으로 생각된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.77-82
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• 1996

The study was performed for the purpose of obtaining the fundamental data to improve the durability of concrete structures due to de-icing salts. To assume the degree of concrete deterioration, soluble chloride content in concrete, the depth of carbonation and compressive strength of core specimens were measured. The porgress of corrosion of concrete bridge was electrochemically monitored. The results show that the concrete structure was deteriorated and reinforced steel in concrete was corroded due to de-icing salts.

• 멤브레인
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• 제1권1호
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• pp.59-59
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• 1991

A theoretical and experimental study made in order to determine the performance of mem-brane contactors in water carbonation is presented. In particular on the basis of experimental results pre-viously obtained it has been derived an expression in which the effect of some parameters as temprera-ture water and CO₂ flow rate CO₂ pressure trans-membrane pressure on the performance of the process is taken into account. The study refers to hollow fiber membrane contactors used for the experimental tests. The main scope has been to verify if by membrane contactors it is possible to reach the same de-gree of water carbonation as by trditional methods (1-5 g/1) and to derive for the module used a cor-relation able to describe the performance of the process at several operating conditions. The high CO₂ removal observed confirms the interesting potentialties of membrane contactors also in gas streams purification.

• Korean Membrane Journal
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• 제1권1호
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• pp.59-64
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• 1999

A theoretical and experimental study made in order to determine the performance of mem-brane contactors in water carbonation is presented. In particular on the basis of experimental results pre-viously obtained it has been derived an expression in which the effect of some parameters as temprera-ture water and {{{{{CO }_{2 } }}}}} flow rate {{{{{CO }_{2 } }}}}} pressure trans-membrane pressure on the performance of the process is taken into account. The study refers to hollow fiber membrane contactors used for the experimental tests. The main scope has been to verify if by membrane contactors it is possible to reach the same de-gree of water carbonation as by trditional methods (1-5 g/1) and to derive for the module used a cor-relation able to describe the performance of the process at several operating conditions. The high {{{{{CO }_{2 } } }}}} removal observed confirms the interesting potentialties of membrane contactors also in gas streams purification.

• Corrosion Science and Technology
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• 제15권1호
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• pp.28-37
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• 2016

Due to the increased construction of offshore concrete structures and the use of de-icing salts for the purpose of snow removal, the needs for the development of anti-corrosive concrete are increasing. To solve these problems, an evaluation of the mechanical and durability properties for concrete were conducted by mixing modified-sulfur as 0 %, 5 %, 10 %, 15 % cement weight ratio. Both strengths and the properties affecting durability such as water absorption coefficient, chloride ion permeability, accelerated carbonation resistance, rapid freezing and thawing, and chemical resistance were evaluated. All evaluations performed were according to the test specifications associated KS. The results indicate that mixing of modified-sulfur lowed chloride ion permeability and improved chemical resistance.

• Smart Structures and Systems
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• 제21권3호
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• pp.305-320
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• 2018

The second half of the 20th century was marked with a significant raise in amount of railway bridges in Austria made of reinforced concrete. Today, many of these bridges are slowly approaching the end of their envisaged service life. Current methodology of assessment and evaluation of structural condition is based on visual inspections, which, due to its subjectivity, can lead to delayed interventions, irreparable damages and additional costs. Thus, to support engineers in the process of structural evaluation and prediction of the remaining service life, the Austrian Federal Railways (${\ddot{O}}$ BB) commissioned the formation of a concept for an anticipatory life cycle management of engineering structures. The part concerning concrete bridges consisted of forming a bridge management system (BMS) in a form of a web-based analysis tool, known as the LeCIE_tool. Contrary to most BMSs, where prediction of a condition is based on Markovian models, in the LeCIE_tool, the time-dependent deterioration mechanisms of chloride- and carbonation-induced corrosion are used as the most common deterioration processes in transportation infrastructure. Hence, the main aim of this article is to describe the background of the introduced tool, with a discussion on exposure classes and crucial parameters of chloride ingress and carbonation models. Moreover, the article presents a verification of the generated analysis tool through service life prediction on a dozen of bridges of the Austrian railway network, as well as a case study with a more detailed description and implementation of the concept applied.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2005년도 High Temperature Superconductivity Vol.XV
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• pp.62-62
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• 2005

• Structural Engineering and Mechanics
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• 제85권2호
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• pp.197-206
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• 2023

The deterioration caused by chloride penetration and carbonation plays a significant role in a concrete structure in a marine environment. The chloride corrosion in some marine concrete structures is invisible but can be dangerous in a sudden collapse. Therefore, as a novelty, this research investigates the ability of a non-destructive damage detection method named the Power Spectral Density (PSD) to diagnose damages caused only by chloride ions in concrete structures. Furthermore, the accuracy of this method in estimating the amount of annual damage caused by chloride in various parts and positions exposed to seawater was investigated. For this purpose, the RC Arosa bridge in Spain, which connects the island to the mainland via seawater, was numerically modeled and analyzed. As the first step, each element's bridge position was calculated, along with the chloride corrosion percentage in the reinforcements. The next step predicted the existence, location, and timing of damage to the entire concrete part of the bridge based on the amount of rebar corrosion each year. The PSD method was used to monitor the annual loss of reinforcement cross-section area, changes in dynamic characteristics such as stiffness and mass, and each year of the bridge structure's life using sensitivity equations and the linear least squares algorithm. This study showed that using different approaches to the PSD method based on rebar chloride corrosion and assuming 10% errors in software analysis can help predict the location and almost exact amount of damage zones over time.

• 한국구조물진단유지관리공학회 논문집
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• 제14권2호
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• pp.171-175
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• 2010

본 연구는 동결융해, 염해 및 중성화가 복합적으로 작용하는 콘크리트 구조물의 내구성능을 평가하기 위하여 일반강도 콘크리트를 대상으로 동결수를 달리하여 동결융해 시험을 실시함으로서 염해와 동결융해 복합작용에 의한 콘크리트의 열화를 평가하였고, 염해, 동결융해 및 중성화의 세가지 열화가 복합적으로 발생되는 복합열화에 대해서는 적절한 평가방법이 부재하여 동결수에 따른 동결융해 시험 후의 시험체에 대하여 중성화 촉진시험을 실시함으로서 복합열화에 의한 콘크리트 내구성능 저하 특성을 평가하고자 하였다. 본 연구를 통하여 동결수의 종류나 물-결합재비 수준과 무관하게 고로슬래그미분말을 사용한 배합의 경우 염해와 동결융해가 동시에 복합적으로 발생되는 환경에서도 우수한 저항성능을 보이는 결과를 나타내므로 동결융해를 포함한 복합열화 환경에서 충분한 내구성 확보를 위해서는 최소한의 설계기준강도의 확보와 고로슬래그미분말 등 적절한 시멘트 결합재의 선정이 무엇보다 중요하다는 결론을 얻었다.

• 자원환경지질
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• 제31권6호
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• pp.463-472
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• 1998

이 연구는 과테말라 에스탄시아 데 라 비르겐 (Estancia de la Virgen) 지역에 분포하는 광화대의 산상과 광물특성을 밝혀내기 위해 수행되었다. 이 연구를 위해 1:2,000 축척의 정밀광상 지질조사가 이루어졌다. 금-은 광화작용은 산 아구스틴 (San Agustin) 단층과 카바나스 (Cabanas) 단층사이의 단층 블럭내에 발달하며 단층구조에 의한 규제를 받았다. 금은 미량에서 부터 최고 72 g/t, 은은 미량에서 초고 180 g/t까지의 품위를 보인다. 정밀광상 지질조사에 의하면 석영맥은 북동방향으로 연장 500 m 이상 추적되며 연속성은 불량하지만 1,000 m 이상 연장되는 양상을 보인다. 석영맥에서의 광물생성순서는 3개 단계를 나눌 수 있다. 1단계에는 황철석, 방연석, 섬아연석, 황동석이 일차 금-은 광물과 수반되며 2단계에는 휘동석, 코벨라이트, 리나라이트와 같은 Cu-Bi-Au-Ag 황화광물이 형성되었으며 이들은 대체로 방연석이나 황동석의 미세구조에 침착-부화되었다. 3단계에는 방연석, 섬아연석의 탄산염화작용, 방연석의 표성부화작용이 지표환경에서 일어났다. 이 과정에서 용탈된 일부 은이 지하수면 근처에서 산화작용이 일어나는 동안 동광석이나 방연석에 침착되었다. 섬아연석과 황동석에서 각기 Fe와 Zn의 함량이 적은 것은 이들 광물이 비교적 저온에서 형성되었음을 의미하며 이는 이전에 연구된 유체포유물의 균일화온도와도 일치한다.