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Crack propagation simulation of concrete with the regular triangular lattice model
조병완,태기호,Erik Schlangen,김창현 한국계산역학회 2005 Computers and Concrete, An International Journal Vol.2 No.2
This paper discusses 2D lattice models of beams for simulating the fracture of brittle materials. A simulation of an experiment on a concrete beam subjected to bending, in which two overlapping cracks occur, is used to study the effect of individual beam characteristics and different arrangements of the beams in the overall lattice. It was found that any regular orientation of the beams influences the resulting crack patterns. Methods to implement a wide range of Poisson뭩 ratios are also developed, and the use of the lattice to study arbitrary micro-structures is outlined. The crack patterns that are obtained with lattice are in good agreement with the experimental results. Also, numerical simulations of the tests were performed by means of a lattice model, and non-integer dimensions were measured on the predicted lattice damage patterns.
조병완,최지선 한국구조물진단유지관리공학회 2012 한국구조물진단유지관리공학회 논문집 Vol.16 No.1
오늘날 첨단산업의 발전과 지구환경 문제의 심각성에 대한 인식이 증가하여 시멘트 산업에서도 다각화 측면에서 다양한 종류의 기술들이 활성화되고 있는 시점이다. 본 연구에서는 최근에 새로이 검토되고 있는 시멘트 대체 재료로서 천연제올라이트를 주원료로 사용한 제올라이트 시멘트 콘크리트에 관한 기초 물성에 대해 분석하는데 목적이 있으며, 악취 및 유독가스 제거기능이 우수하며 중금속, 암모니아와 같은 양이온성 오염물질을 제거하는 이온교환능, 흡착능, 분자체효과를 가지며 또한 다공성 물질이라 보온능력이 좋은 것으로 알려진 천연제올라이트와 알칼리 활성제(NaOH)의 양에 따라 콘크리트의 압축강도, 슬럼프, 블리딩 및 공기량 등을 실험하였다. 천연제올라이트 콘크리트의 압축강도 측정결과 거의 40MPa정도로 측정되었으며 슬럼프, 블리딩, 공기량 시험에서도 일반 콘크리트과 비슷한 성능을 나타내어 향후 고성능, 고기능성 건설재료로 사용 가능하다고 판단되어진다. Since the cement industry is expected to face serious setbacks in the near future associated with environmental concerns. With the advent of new technologies and increased public awareness about global environmental issues, the cement industry is actively seeking to adopt new technologies as part of an effort to diversity its resources. This study is designed to assess the fundamental properties of zeolite cement concrete which consists mainly of natural zeolite, which is known for removal of and harmful gas, ion exchange capacity removing cation contaminant including heavy metals and ammonia, absorptive capacity and molecular sieving effect together with excellent insulation capacity as a porous material, and recently draws much attention for its possibility as an alternative material to cement. The study was conducted to show the compressive strength of concrete, slump, bleeding and air volume according to the changes of natural zeolite and alkali activator(NaOH). As a result of measuring the compressive strength of natural zeolite concrete, it was almost 40MPa and displayed similar to general concrete in the tests of slump, bleeding and air volume, with which it was considered that it may be used as a future high performance, high performance construction material.
압전 소자를 이용한 에너지 하베스팅의 전기방식 적용의 기초연구
조병완,김영석,김희현,이동윤,이윤성 한국구조물진단유지관리학회 2012 한국구조물진단학회 학술발표회논문집 Vol.2012 No.1
This study informs regarding application to electric protection by using piezoelectric material which is one of the energy harvesting system in bridge. It can transform from strain energy to electricity energy by using piezoelectric material as strain energy always occurs in bridge. This paper suggests that electricity energy occurred from piezoelectric material can use cathodic protection by power impressed methods for anti corrosion of reinforcement bar, steel and so on.
센서네트워크를 이용한 FCM 교량의 처짐 관리 방안 연구
조병완,태기호,권오혁,Jo, Byung-Wan,Tea, Ghi-Ho,Kwon, Oh-Hyuk 한국방재학회 2008 한국방재학회논문집 Vol.8 No.4
본 연구에서는 FCM 교량의 시공 시 발생하는 처짐과 시공 후 발생하는 처짐의 관리를 위해 센서 네트워크를 활용한 처짐 관리 기술을 제안하고자 하였으며, 센서에 의한 검증실험과 제안된 USN를 이용하여 실제 건설되어지고 있는 현장에 적용함으로써 그 효율성을 입증하였다. 향후, USN은 교량의 장거리 건전도 모니터링에 매우 유용할 것이라 생각된다. Ubiquitous technology is proposed which is used wireless sensor network for deflection management at casting and after casting of FCM bridge. Proposed method are analyzed which are sensor experiment and existing FCM bridge using ubiquitous sensor network. Wireless sensor network enables low-cost sensing of environment. As a results, the field application shows that USN is useful method for structural health monitoring system which long distance away.
Investigations on the Development of Powder Concrete with Nano-SiO2 Particles
조병완,Chang Hyun Kim,Jae Hoon Lim 대한토목학회 2007 KSCE JOURNAL OF CIVIL ENGINEERING Vol.11 No.1
The nano scale of particles can result in dramatically improved or diferent properties from conventional grain-size materials of thesame chemical composition. Therefore, it is practical to add nano-silica in particle form with 99.9% of SiO2 in nano scale to improvethe characteristics of cement mortar. The compressive strengths of cement mortar were evaluated at various water-cementitious ratio.Five diferent water-cementitious ratios were used including, 0.23, 0.25, 0.32, 0.35, and 0.48 and four contents of nano-SiO2particles, 3%, 6%, 9%, and 12% by weight of cement. The compresive strength of cement mortar with the addition of silica fumewere also evaluated at w/cm ratio of 0.48 to compare with mortar containing nano-SiO2 particles and three contents of silica fumewere: 5%, 10% and 15% by weight of cement. The experimental results show that the compressive strengths of mortars with nano-SiO2particles were more valuable in enhancing strength than silica fume. This paper also analyzed some available examinations tomonitor the hydration progress continuously, such as SEM observation, residual quantity test for Ca(OH)2 and the rate of heatevolution. The results of the examinations indicate that the SiO2 in nano scale behave not only as a filler to improve themicrostructure, but also as an activator to promote pozzolanic reactions.
조병완,최지선,강석원 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.3
Portland cement is the essential binding agent in concrete. This cement is becoming a principal factor in air pollution because of the creation of CO2 during its manufacture. The exhaustion of the natural resources needed for Portland cement production is also an issue. Therefore, a substitute material for this type of cement is needed. Nano-scale materials are of great interest due to their unique optical, electrical, and magnetic properties. These properties are strongly dependent on the sizes and shapes of the particles, and, therefore, it is important to be able to develop a construction route which retains the excellent properties of the nano-sized material. The purpose of this study was to synthesize nano-powder as a substitute for cement using a chemical method. Particle size, SEM, EDX, and porosity tests were conducted. This study investigated the compressive strengths of concretes with various compositions. Specimens were tested for compressive strength three, seven, 14, and 28 days after manufacture. In the results of this study, the medium-sized (50% by weight) nano-cement particles created via chemical synthesis were less than 168 nm in size, and the compressive strength of the mortar prepared using these nanoparticles was 53.9MPa.