시멘트 산업의 탄소중립 기술 발전 방향

염우성 한국도로학회 2024 한국도로학회지 Vol.26 No.1

충격반향기법에 의한 콘크리트 포장 공동여부 확인 초기연구

염우성,박주영,송기일,유주호,정진훈 한국도로학회 2013 한국도로학회 학술대회 발표논문 초록집 Vol.2013 No.09

건설당시 엄격한 다짐관리로 시공된 노상과 보조기층은 공용기간이 경과함에 따라 압밀침하, 배수불 량, 그리고 지하수위 상승 등의 원인으로 품질이 저하된다. 지반에 변형이 생기면 포장표층과 지반사이에 공동이 발생되며, 여기에 하중이 재하 되면 설계 당시 예상한 것보다 더 큰 응력이 발생하여 포장에 파손이 발생하고 결과적으로 공용성이 저하되는 등의 문제가 발생할 수 있다(박주영 등, 2013). 따라서, 포장 하부 공동유무의 평가는 매우 중요하지만, 육안으로 확인하는 것은 불가능하므로 비파괴 방법을 사용하여야 한다. 구조물 내의 이격된 공간을 검사하는 비파괴 방법 중 하나인 충격반향기법(Impact-Echo Method)은 많은 분야에서 사용되고 있지만 포장하부의 공동탐사에 적용된 사례는 드물다. 충격반향기법은 그림 1과 같이 구조물에 응력파(Stress wave)를 발생시켜 그 응답을 분석하여 결함을 탐지하는 방법이다(Sansalone et. al., 1986). 응력파는 가진력을 일으킬 수 있는 장비에 의해 발생되며 표면과 내부결함 사이에서 다중반사가 일어나면서 일시적인 공진이 발생하여 구조물의 상태를 평가한다. 본 논문에서는 충격반향기법을 콘크리트 포장 하부 공동유무 평가에 적용하기 위한 기초연구를 수행하 였다. 먼저, 콘크리트 포장의 구조적 특징, 물성값, 각 층간의 댐핑계수(Damping Coefficient) 등을 조사 하였다. 조사된 자료를 바탕으로 상용 프로그램 ABAQUS를 이용하여 2D 유한요소해석을 실시하였다. 시간이력해석을 위해 Dynamic-explicit 방법을 적용하여 충격반향기법을 모사하였으며, 동적해석을 통해 콘크리트 포장의 공동의 유무에 따른 응력파 정보를 수집하였다. 최종적으로 획득된 응력파에 대하여 공동의 존재 여부 및 단면에 따른 거동차이를 비교·분석 하였다

폐비닐 골재가 혼합된 시멘트 콘크리트의 열 특성

염우성,안기홍,유주호,정진훈 한국도로학회 2014 한국도로학회논문집 Vol.16 No.6

PURPOSES : In this study, wasted vinyl aggregate, which possesses better thermal properties than natural aggregate, was used in cementconcrete mixture to develop more economical concrete with thermal insulation and freeze prevention effects. METHODS : Slump and air content of the fresh concrete, which substituted its 0%, 5%, and 10% of coarse aggregate with wasted vinylaggregate, were measured. Compressive strength, Poisson’s ratio, elastic modulus, and splitting tensile strength of hardened concrete weremeasured by laboratory tests. Thermal properties of concrete such as coefficient of thermal expansion, thermal conductivity, and specific heatwere also measured according to replacement ratio of wasted vinyl aggregate. Finally, the thermal insulation and freeze preventioneffectiveness of the concrete mixed with wasted vinyl aggregate was confirmed through finite element analysis of road pavement crossingabove concrete box culvert made from wasted vinyl aggregate. RESULTS: Even though the physical properties of wasted-vinyl-aggregate concrete such as compressive strength, Poisson°Øs ratio, elasticmodulus, and splitting tensile strength were inferior to those of ordinary concrete, they met requirements for structural concrete. The thermalproperties of concrete were improved by wasted vinyl aggregate because it decreased thermal conductivity and increased specific heat of theconcrete. According to the result of finite element analysis, temperature variation in pavement subgrade was mitigated by box culvert madefrom wasted-vinyl-aggregate concrete. CONCLUSIONS: Through the laboratory test and finite element analysis of this study, it was concluded that the concrete structures madefrom wasted vinyl aggregate showed thermal insulation and freeze prevention effects.

포장하부 매설물 및 지반열화에 따른 소형루프 전자탐사신호 분석

염우성,이상직,최민규,송기영,안준상,정진훈 한국도로학회 2019 한국도로학회 학술대회 발표논문 초록집 Vol.2019 No.09

한국세라믹기술원 탄소중립센터

염우성 한국도로학회 2023 한국도로학회지 Vol.25 No.2

수평으로 경사진 박스암거 위 콘크리트 포장 슬래브의 최적 줄눈위치

염우성,정호성,연우,손덕수,이재훈,정진훈 한국도로학회 2013 한국도로학회논문집 Vol.15 No.5

PURPOSES : The purpose of this study is to investigate the optimal joint positions which can minimize distresses of concrete pavement containing box culvert with horizontally skewed angles. METHODS : The concrete pavement containing the box culvert with different skewed angles and soil cover depths was modeled by 3dimensional finite element method. The contact boundary condition was used between concrete and soil structures in addition to the nonlinear material property of soil in the finite element model. A dynamic analysis was performed by applying the self weight of pavement, negative temperature gradient of slab, and moving vehicle load simultaneously. RESULTS: In case of zero skewed angle (0。), the maximum tensile stress of slab was the lowest when the joint was positioned directly over side of box culvert. In case there was a skewed angle, the maximum tensile stress of slab was the lowest when the joint passed the intersection between side of the box culvert and longitudinal centerline of slab. The magnitude of the maximum tensile stress converged to a constant value regardless the joint position from 3m of soil cover depth at all of the horizontally skewed angles. CONCLUSIONS: More reasonable and accurate design of the concrete pavement containing the box culvert can be possible based on the research results.

하버드 상위 1퍼센트의 비밀

염우성 한국도로학회 2021 한국도로학회지 Vol.23 No.1

FWD 방향을 고려한 콘크리트 포장하부 유한요소 해석

염우성,이재훈,이재훈,이기상,정진훈 한국도로학회 2014 한국도로학회 학술발표회 논문집 Vol.2014 No.3

회전익 자동비행제어시스템 소프트웨어의 FMET 수행 및 검증 방안

염우성(WooSung-Yeom),하석운(Seokwun-Ha) 한국항공우주학회 2020 韓國航空宇宙學會誌 Vol.48 No.1

회전익 헬리콥터의 안정성, 조종성 향상 및 증대를 보장하기 위해서는 디지털 제어기술에 의한 디지털 비행제어시스템의 개발이 필요하다. 헬리콥터 비행제어시스템 설계 및 개발 기술은 해외선진 항공 개발사의 기술이전 기피 및 불가에 해당하는 핵심기술로써 헬리콥터 비행제어 시스템 운용소프트웨어인 OFP의 기능 요구조건 충족과 더불어 비행안전에 직결되는 시스템 신뢰도의 검증이 필요하며 비행제어 시스템 운용 소프트웨어의 검증 방안 연구는 무엇보다 중요하다. 본 논문에서는 회전익 자동비행제어시스템 소프트웨어의 FMET 수행 및 검증 방안에 관한 연구를 수행하였다. It is necessary to develop digital flight control system by digital control technology to ensure stability and maneuverability of rotary helicopter. It is important to meet functional requirements of helicopter flight control system OFP and verify system reliability directly linked to flight safety as a core technology that avoids the transfer of technology by overseas advanced helicopter manufacturer. In this paper, we studied how to perform FMET for operational flight program of rotary automatic flight control system.

폐비닐 골재가 혼합된 시멘트 콘크리트의 열 특성

염우성,안기홍,유주호,정진훈 한국도로학회 2014 한국도로학회논문집 Vol.16 No.6

PURPOSES : In this study, wasted vinyl aggregate, which possesses better thermal properties than natural aggregate, was used in cement concrete mixture to develop more economical concrete with thermal insulation and freeze prevention effects. METHODS : Slump and air content of the fresh concrete, which substituted its 0%, 5%, and 10% of coarse aggregate with wasted vinyl aggregate, were measured. Compressive strength, Poisson’s ratio, elastic modulus, and splitting tensile strength of hardened concrete were measured by laboratory tests. Thermal properties of concrete such as coefficient of thermal expansion, thermal conductivity, and specific heat were also measured according to replacement ratio of wasted vinyl aggregate. Finally, the thermal insulation and freeze prevention effectiveness of the concrete mixed with wasted vinyl aggregate was confirmed through finite element analysis of road pavement crossing above concrete box culvert made from wasted vinyl aggregate. RESULTS: Even though the physical properties of wasted-vinyl-aggregate concrete such as compressive strength, Poisson°Øs ratio, elastic modulus, and splitting tensile strength were inferior to those of ordinary concrete, they met requirements for structural concrete. The thermal properties of concrete were improved by wasted vinyl aggregate because it decreased thermal conductivity and increased specific heat of the concrete. According to the result of finite element analysis, temperature variation in pavement subgrade was mitigated by box culvert made from wasted-vinyl-aggregate concrete. CONCLUSIONS: Through the laboratory test and finite element analysis of this study, it was concluded that the concrete structures made from wasted vinyl aggregate showed thermal insulation and freeze prevention effects.