시멘트 페이스트 경화체의 self healing 특성

김재영(Kim Jae Young),변승호(Byun Seung Ho) 대한토목학회 2008 대한토목학회논문집 A Vol.28 No.2A

콘크리트의 균열이 수밀성을 떨어트리고 내구성을 악화시키는 것은 이미 잘 알려진 사실이다. 균열에 의한 이러한 성능저하는, 콘크리트에 균열이 발생하면 물 뿐만이 아니라 염화물, 이산화탄소, 황산염과 같이 유해한 물질들의 침투가 용이해지기 때문이다. 하지만 균열이 물과 접촉하는 경우 일부는 폐쇄 된다. 이러한 현상을 self-healing이라고 하며, self-healing은 균열면에서 새로이 생성되는 수화물과 밀접한 관련이 있다. 콘크리트의 self-healing과 관련한 상당수의 연구에서 공통적으로 균열면 표면에서 CSH겔이 관찰됨을 확인하였다. 그러나 self-healing에 관한 일부 연구에서는 CSH겔 뿐만 아니라 수산화칼슘 및 에트링자이트가 균열 표면에서 관찰되었다고 보고하였다. 본 연구에서는 self-healing에 의한 수화생성물을 확인하고자 하였으며, 또한 구체방수재가 self-healing에 미치는 영향을 평가하고자 하였다. 균열 표면에 대하여 XRD, DSC, SEM, EDX 분석을 실시한 결과 시멘트계에서 self-healing은 CSH겔, 수산화칼슘, 에트링자이트와 연관이 있음을 확인하였다. 또한 구체방수재가 섬유상(또는 침상)의 수화물의 생성을 촉진하고 이들 수화물이 망목구조 형태를 이루는 것을 확인하였다. 이러한 섬유상의 수화물이 시멘트 계의 self-healing에 매우 효과적인 것으로 판단된다. It is well known that cracks in concrete decrease permeability and durability of concrete because cracks enhance the penetration of water or corrosive chemicals like as chlorides, carbon dioxides, sulfates and some others. But some of cracks in hardened cements may be sealed in case of contacting water. This phenomenon is called "self healing" and it has a close relation to hydration products newly formed on surfaces of cracks. Many studies on self healing in concretes commonly showed that CSH gel has been observed on crack surfaces. And some studies have reported that calcium hydroxides and ettringite were observed as well as CSH gel on crack surfaces. This study was carried out to investigate hydration products formed by self healing process and also examine the influence of waterproof admixture for concretes on self healing of cement. As a result of XRD, DSC, SEM and EDX analysis of crack surfaces, it was found that self healing of cement was related to CSH gel, calcium hydroxides and ettringite. And waterproof admixture increased fibrous (needle-like) hydration products which were in network form. It is estimated that such fibrous products are effective for self healing process of cement system.

Experimental characterization of the self-healing capacity of cement based materials and its effects on the material performance: A state of the art report by COST Action SARCOS WG2

Ferrara, Liberato,Van Mullem, Tim,Alonso, Maria Cruz,Antonaci, Paola,Borg, Ruben Paul,Cuenca, Estefania,Jefferson, Anthony,Ng, Pui-Lam,Peled, Alva,Roig-Flores, Marta,Sanchez, Mercedes,Schroefl, Christ Elsevier 2018 Construction and Building Materials Vol.167 No.-

<P><B>Abstract</B></P> <P>Heuristically known at least since the first half of XIX century, the self-healing capacity of cement-based materials has been receiving keen attention from the civil engineering community worldwide in the last decade. As a matter of fact, stimulating and/or engineering the aforementioned functionality via tailored addition and technologies, in order to make it more reliable in an engineering perspective, has been regarded as a viable pathway to enhance the durability of reinforced concrete structures and contribute to increase their service life.</P> <P>Research activities have provided enlightening contributions to understanding the mechanisms of crack self-sealing and healing and have led to the blooming of a number of self-healing stimulating and engineering technologies, whose effectiveness has been soundly proved in the laboratory and, in a few cases, also scaled up to field applications, with ongoing performance monitoring. Nonetheless, the large variety of methodologies employed to assess the effectiveness of the developed self-healing technologies makes it necessary to provide a unified, if not standardized, framework for the validation and comparative evaluation of the same self-healing technologies as above. This is also instrumental to pave the way towards a consistent incorporation of self-healing concepts into structural design and life cycles analysis codified approaches, which can only promote the diffusion of feasible and reliable self-healing technologies into the construction market.</P> <P>In this framework the Working Group 2 of the COST Action CA 15202 “Self-healing as preventive repair of concrete structures – SARCOS” has undertaken the ambitious task reported in this paper. As a matter of fact this state of the art provides a comprehensive and critical review of the experimental methods and techniques, which have been employed to characterize and quantify the self-sealing and/or self-healing capacity of cement-based materials, as well as the effectiveness of the different self-sealing and/or self-healing engineering techniques, together with the methods for the analysis of the chemical composition and intrinsic nature of the self-healing products. The review will also address the correlation, which can be established between crack closure and the recovery of physical/mechanical properties, as measured by means of the different reviewed tests.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Review of test methods for assessing healing efficiency. </LI> <LI> Novel perspective in correlating healing to durability and mechanical recovery. </LI> <LI> Correlation between different test methods. </LI> <LI> Characterization methods of healing products. </LI> <LI> Pioneer monitored case studies are presented. </LI> </UL> </P>

대학 글쓰기 교육에서 자기 성찰적 글쓰기를 위한 제언 -글쓰기의 자구적 치유와 심리의학적 치유의 구별을 중심으로-

정연희 ( Yeon Hee Jeong ) 우리어문학회 2012 우리어문연구 Vol.43 No.-

This article tried to consider mixing between self-helf healing of writing and psychology healing in the self-reflection writing, and distinguish two conception of healing. There are the commonness between self-helf healing of writing and psychology healing, and then it makes the question of self-discovery difficult and vague. This caused confusion and dilemma in the classroom management. There are two concepts of healing in the class of writing need to be distinguished. And writing should be made in the class of writing. The self-reflection writing is connected to self-discovery and self-interpretation due to the nature of writing. Therefore refrain from the use of psychology concepts in the self-reflection writing shall be. This makes student writer contracted, and makes confusion between self-helf healing of writing and psychology healing in the self-reflection writing. The self-understanding by writing is self-interpretation, and the self-interpretation is that discovers the special mediation in the many signs and the diverse symbols, and in their stories. That is to say, it is to call attention to the details in life and experience, and the sign and symbol in circumstance and experience. Writers, thereby, understand and interpretate these. And writers discover the ego, and their the self is connected to the overall life, and they feel the self-sustainability. These self-helf healing of writing is in accord with the aim of general writing of college.

<누항사> 창작에 발현된 자기치유기제의 가치 모색

박태진 ( Park Tae Jin ) 한국고전문학교육학회 2013 고전문학과 교육 Vol.25 No.-

이 논문은 자기치유적 관점에서 <누항사> 창작에 발현된 자기치유기제의 가치를 모색하는 것을 목적으로 한다. 연구자는 <누항사(陋巷詞)>의 창작 배경이 박인로의 가난 체험과 연관이 있음을 검토했다. 이에 <누항사(陋巷詞)> 창작을 자기치유적 관점으로 접근할 필요성을 살폈다. 또한 <누항사(陋巷詞)>를 창작할 때 치유작용의 기제와 치유요소의 기제가 상호작용하여 자기치유기제가 발현됨을 고찰했다. 이런 관점에서 <누항사(陋巷詞)>를 창작할 때, 창작 주체인 박인로는 서사 단락에서는 ‘노출’과 ‘대장부의 기개’와 ‘안빈일념’, 본사 단락에서는 ‘노출’과 ‘희망’, 결사 단락에서는 ‘전환’, ‘성찰’, ‘강화’와 ‘안빈낙도’와 ‘의지’ 등의 자기치유기제가 발현되어 박인로의 가난 관련 궁고함을 해결하는 역할을 함을 살폈다. 본고는 다음과 같은 점에서 연구 의의가 있다. 먼저, <누항사> 창작에 박인로의 가난 체험이 반영된 것을 규명했다는 점이다. 둘째, <누항사> 창작을 자기치유적 관점에서 주목할 필요가 있다는 점이다. 셋째, <누항사> 창작에는 치유작용의 기제와 치유요소의 기제들이 상호작용하여 자기치유기제로 발현된다는 점이다. 넷째, <누항사> 창작에 발현된 자기치유기제들은 창작주체의 자기를 치유하는 데 중요한 역할을 한다는 점이다. 이런 점에서 <누항사> 창작에 발현된 자기치유기제들은 가사창작교육의 새로운 활로를 여는 데 기여할 수 있다. 그러나 <누항사> 창작에 발현된 자기치유기제를 학교 현장의 청소년들에게 가르칠 때, 기대한 만큼 효용을 볼 수 있는지는 앞으로 연구할 과제다. The aim of this study is focusing on searching value of mechanism for self-healing appeared in creative writing of 「Nu Hang Sa」 with the point of self-healing. First of all, creative writing's background of 「Nu Hang Sa」 is connected with penury experience of Park In No(朴仁老 : 1561~1642). therefore, it is necessary that creative writing of 「Nu Hang Sa」 should be searched with the point of self-healing for mental pain including penury experience of Park In No. Also, researcher studied that self-healing appearing in creative writing of 「Nu Hang Sa」 and mechanism for self-healing that is composed 'operating's mechanism' and 'factor's mechanism'. Namely, when Park In No do creative writing 「Nu Hang Sa」, 'operating's mechanism' as exposure for self-healing and 'factor's mechanism' as being content amid poverty and taking pleasure in acting in an honest way appear, he has his pain get better. Therefore, this study have important meaning as follows. First, creative writing of 「Nu Hang Sa」 is connected with penury experience of Park In No. Second, creative writing of 「Nu Hang Sa」 should be accessible with the point of self-healing. Third, mechanism for self-healing that is composed 'operating's mechanism' and 'factor's mechanism' appeared and help Park In No for self-healing in creative writing of 「Nu Hang Sa」. Fourth, mechanism for self-healing appeared in creative writing of 「Nu Hang Sa」 can open a new way in creative writing's education of literature. But, mechanism for self-healing appeared in creative writing of 「Nu Hang Sa」 have a useful value to students in middle or high school should be studied more deeply in th future.

자기치유 중심의 시조창작교육의 가능성 모색

박태진 ( Tae Jin Park ) 고려대학교 한국어문교육연구소 2013 한국어문교육 Vol.13 No.-

이 연구는 자기치유 중심의 시조창작교육의 가능성을 모색하는 것을 목적으로 한다. 연구자는 먼저, 문학교육에서 자기의 개념이 필요하고 시조창작에서 자기치유의 속성이 나타남을 검토했다. 이후 자기치유능력의 형성 및 신장에 적합한 시조창작교육의 목표와 내용을 탐색했다. 이러한 연구를 기반으로 성남 S고등학교 학생을 대상으로 자기치유 중심의 시조창작교육을 실천하고 그 사례를 분석해 보았다. 이 결과 잠정적이지만, 자기치유 중심의 시조창작교육이 가능함을 알 수 있었다. 본고의 의의는 먼저, 일상에서 심리적 상처를 입게 될 경우, 시조창작을 통한 자기치유의 교육이 필요하다는 점이다. 둘째, 시조 창작에 치유성이 나타남을 알고, 시조창작을 통해 자기치유의 체험을 할 수 있다는 점이다. 셋째, 시조창작을 통한 자기치유를 생활화할 수 있다는 점이다. 그러나 본고는 시론적 성격이 짙은 연구로, 보다 심화된 이론적 배경 및 교수학습과 평가 방법을 마련하기 위한 후속의 연구가 요구된다. The aim of this study is searching on possibility about education of Shi-jo(時調)`s creative writing focusing on self-healing. Researcher studied that concept of self in literature`s education is necessary and attribute of self-healing in Shi-jo(時調)`s creative writing happen. And researcher found goal and contents for education of Shi-jo(時調)`s creative writing to form and extend capability of self-healing. With this kinds of form and extend capability of self-healing. With this kinds of studies, researcher taught S high school`s with this kinds of studies, researcher taught S high school`s student of Sung-Nam city with Shi-jo(時調)`s creative writing focusing on self-healing and analyzed cases of a class in S high school located in south of Korea. Finally, researcher provisionally concluded that education of Shi-jo(時調)`s creative writing focusing on self-healing is possible. Therefore, this study have important meaning as follows. First, when students in high school get penury experience, education of Shi-jo(時調)`s creative writing focusing on self-healing is necessary. Second, students in high school know that attribute of self-healing happen and can get experience of self-healing in Shi-jo(時調)`s creative writing. Third, students in high school can get value of self-healing appearing in Shi-jo(時調)`s creative writing to be a part of his life. But, problems concerning with teaching method and assessment about Shi-jo(時調)`s creative writing focusing on self-healing should be solved in the future.

Photo-polymerized self-healing polymer with improving mobility of dangling chains

송다빈,최경환,서동학 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Self-healing materials can spontaneously repair themselves after external stimuli. The self-healing hydrogels is achieved a fast selfhealing through mediators such as water that improve the mobility of self-healing moieties. However, mediators are essential for rapid selfhealing due to chemical cross-link. Recently, photo-polymerized thin film self-healing polymer is developed by the introduction of healer, polyhydric alcohol, that can replace chemical cross-link with physical cross-link for increasing mobility of self-healing moieties. Although thin-film self-healing polymer achieved fast scratch recovery, a monomer of it is still oppressed their self-healing ability due to the densest phase. Here, we introduce a novel monomer that creates an inner-space by steric hindrance. As a result, the polymer has improved mobility for rapid self-healing. Moreover, It can be made of transparent film through photo-polymerization. It is expected to be applied for scratch film and coatings.

Advances in self-healing materials based on vascular networks with mechanical self-repair characteristics

Lee, Min Wook,An, Seongpil,Yoon, Sam S.,Yarin, Alexander L. Elsevier 2018 Advances in colloid and interface science Vol.252 No.-

<P><B>Abstract</B></P> <P>Here, we review the state-of-the-art in the field of engineered self-healing materials. These materials mimic the functionalities of various natural materials found in the human body (e.g., the healing of skin and bones by the vascular system). The fabrication methods used to produce these “vascular-system-like” engineered self-healing materials, such as electrospinning (including co-electrospinning and emulsion spinning) and solution blowing (including coaxial solution blowing and emulsion blowing) are discussed in detail. Further, a few other approaches involving the use of hollow fibers are also described. In addition, various currently used healing materials/agents, such as dicyclopentadiene and Grubbs' catalyst, poly(dimethyl siloxane), and bisphenol-A-based epoxy, are described. We also review the characterization methods employed to verify the physical and chemical aspects of self-healing, that is, the methods used to confirm that the healing agent has been released and that it has resulted in healing, as well as the morphological changes induced in the damaged material by the healing agent. These characterization methods include different visualization and spectroscopy techniques and thermal analysis methods. Special attention is paid to the characterization of the mechanical consequences of self-healing. The effects of self-healing on the mechanical properties such as stiffness and adhesion of the damaged material are evaluated using the tensile test, double cantilever beam test, plane strip test, bending test, and adhesion test (e.g., blister test). Finally, the future direction of the development of these systems is discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An overview of the mechanical property recovery in self-healing engineering materials of vascular type is given. </LI> <LI> Novel up-to-date approaches to fabrication of engineering self-healing materials are described. </LI> <LI> The physical and chemical healing mechanisms including chemical reactions are considered and characterized in detail. </LI> <LI> The self-healing manifestations in the restoration of mechanical and anti-corrosive properties are discussed. </LI> <LI> The scale-up industrial perspectives of self-healing nanofibers are highlighted. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Grubbs` Catalyst의 열안정성 및 자가치료제와의 반응성 평가

윤성호 ( Sung Ho Yoon ),( Ya Long Shi ),( Jun Feng ),장세용 ( Se Yong Jang ) 한국복합재료학회 2015 Composites research Vol.28 No.6

본 연구에서는 자가손상보수에 적용되는 Grubbs’ catalyst의 열안정성과 자가치료제와의 반응성을 조사하였다. 이를 위해 제조사에서 공급된 4종류를 고려하였으며 제조사에서 공급받은 상태와 기계적으로 분쇄시킨 상태로 시험하였다. 자가치료제는 Dicyclopentadiene (DCPD)과 5-ethylidene-2-norbonene (ENB)을 적절한 비율로 혼합한 4종류를 고려하였다. 촉매의 열안정성을 조사하기 위해 시차주사 열량측정장치를 통해 온도에 따른 열흐름변화를 측정하였다. 자가치료제와의 반응성을 평가하기 위해 촉매와 혼합된 자가치료제의 반응열을 측정하였다. 이때 촉매는 자가치료제와 반응할 때의 최대온도와 최대온도 도달시간을 고려하여 Fluka Chemika Grubbs’ catalyst를 적용하였다. 연구결과에 따르면 촉매는 제조사에 따라 다른 형상을 나타내며 입자의 크기가 작은 촉매가 자가 치료제와 높은 반응성을 나타내었다. ENB의 혼합비가 높은 자가치료제가 촉매와 혼합되면 최대온도는 증가하고 최대온도 도달시간은 빨라졌다. 또한 촉매의 양이 많을수록 최대온도는 높아지고 최대온도 도달시간은 빨라졌다. 촉매의 열안정성과 자가치료제와의 반응성을 고려할 때 0.5 wt% 촉매와 D3E1 자가치료제가 자가손상보수를 위한 최적 조건임을 알 수 있었다. 마지막으로 노출된 분위기 온도에 따라 촉매에 열분해가 발생할 수 있기 때문에 촉매가 열안정성을 갖는 온도보다 높은 온도에 노출되지 않도록 하여야 한다. This study investigated the thermal stability of Grubbs’ catalyst and its reactivity with self-healing agents for self-healing damage repair. Four types of Grubbs’ catalyst supplied by manufacturers were considered and each catalyst was tested in as-received and grinded conditions. Four types of self-healing agents were prepared by varying the mixing ratio of dicyclopentadiene (DCPD) and 5-ethylidene-2-norbonene (ENB). Heat flows as a function of temperature were measured through a differential scanning calorimetry (DSC) to determine the thermal stability of catalysts. Reaction heats of self-healing agents with the catalyst were measured to evaluate the reactivity of the catalyst. For this evaluation, Fluka Chemika Grubbs’ catalyst was used based on the maximum temperature and the time to reach the maximum temperature. According to the results, catalysts had different shapes depending on the manufacturer and the results showed that the smaller the size of the catalyst the higher the reactivity with self-healing agents. As the ENB ratio in self-healing agents increased, the maximum temperature increased, and the time to reach the maximum temperature decreased. As the amount of the catalyst increased, the maximum temperature increased, and the time to reach the maximum temperature decreased. Considering the thermal stability of the catalyst and its reactivity with the self-healing agent, combination of 0.5 wt% catalyst and the D3E1 self-healing agent was optimal for self-healing damage repair. Finally, as the thermal decomposition may occur depending on the environmental temperature, the catalyst must not be exposed to temperature higher than that is necessary to maintain the thermal stability of the catalyst.

Based on Multi-Thread Dynamic Self-Healing Technology Application Research in Big Data Image Processing

Guangyu Xu,Xiaohua Qiao 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.6

With the rapid development of information technology, the data scale expands unceasingly, produce a large amount of image data, a massive image data processing has also is an important technology. Traditional processing techniques, in dealing with such a large scale of image data, have been unable to meet the requirements. One of the important reason is that whether the c ++ or Java, there is memory leak problem, when the data is the relatively small size, these problems may be insignificant, but when the data is very large, will highlight these shortcomings, will lead to serious program crashes, the system outage, ultimately unable to achieve expected goal. In considering the data processing efficiency, stability, is proposed in this paper, based on multithreading, a dynamic self-healing capacity of mass image data processing technology, compared with the traditional technology can improve the efficiency and improve the stability. Finally, after the experimental results verify that the method is effective.

Quantitative evaluation of crack self-healing in cement-based materials by absorption test

Park, Byoungsun,Choi, Young Cheol Elsevier 2018 Construction and Building Materials Vol.184 No.-

<P><B>Abstract</B></P> <P>This study investigates the self-healing performance of cement-based materials using the water absorption test. The experimental method was performed in compliance with ASTM C 1585 on paste specimens mixed with research cement (RC), ground granulated blast-furnace slag (GGBS), anhydrite, and calcium sulfo-aluminate (CSA) expansion agents as inorganic binders. The water flow test was also performed for comparison and the self-healing products were analyzed. The results showed that the proposed method using the water absorption test could effectively evaluate the self-healing performance and that the mixture with GGBS and CSA expansion agents displayed the best performance. The temporal variation in water absorption rates was used to analyze the effects of primary self-healing (due to the further hydration of unreacted materials) and secondary self-healing (due to ion diffusion). The analysis provided results similar to those of the water absorption test. A comparison with an experiment on self-healing products confirmed that the amount of generated calcite had a larger effect on self-healing than the total amount of self-healing products.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Water absorption test was used to evaluate the self-healing performance of cement-based materials. </LI> <LI> Various types of cement based materials tested. </LI> <LI> Self-healing mechanism by further hydration and calcium ion diffusion was examined. </LI> </UL> </P>