• Title, Summary, Keyword: 자기치유

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Evaluation of Self-Healing Performance for Mortar Beams Containing Self-Healing Materials (자기치유 재료 혼입 모르타르 보의 자기치유 성능 평가)

  • Shin, DongIk;Muhammad, Haroon;Min, Kyung Sung;Lee, Kwang-Myong;Lee, Jung-Yoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.1
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    • pp.67-73
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    • 2020
  • In this study, the self-healing performance of mortar beams containing self-healing materials was evaluated through experiments. Normal mortar beams and self-healing mortar beams were used In the experiments. The self-healing performance was evaluated by comparing the mortar compressive strength, member strength, and self-healing effects of cracks. The experimental results showed that the compressive strength of mortar containing self-healing material was smaller than that of normal mortar, but the ratio of 118 days compressive strength to 28 days compressive strength was the same. The member strength tended to increase with increasing curing period. In normal mortar specimens, the member strength did not recover even if the curing period increased, but the strength of the self-healing mortar specimens tended to recover as reaction products were produced. The crack width tended to decrease after the healing periods in both specimens, but the reaction product was observed only in the self-healing mortar specimens.

A Study on Crack Healing Properties of Cement Composites Mixed with Self-healing Microcapsules (자기치유 마이크로 캡슐을 혼합한 시멘트 복합재료의 품질 및 균열 치유 특성에 관한 실험적 연구)

  • Choi, Yun-Wang;Oh, Sung-Rok;Kim, Cheol-Gyu;Nam, Eun-Joon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.1
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    • pp.113-121
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    • 2019
  • In this study, self - healing microcapsules which can be mixed directly with cement composites were prepared, and the quality and crack healing performance of cement composites with self - healing microcapsules were evaluated. In the past, it has been focused on evaluating self-healing capsules and crack healing properties. Therefore, self - healing microcapsules have been studied for their effect on the quality of cement composites when mixed with cement composites. The table flow and the air flow rate of the cement composite material mixed with self-healing microcapsules were found to have no significant influence on table flow and air volume regardless of mixing ratio. Compressive strength and splitting tensile strength tended to decrease with increasing capsule mixing ratio. As a result of evaluation of crack healing properties according to water flow, initial water permeability decreased, and reaction products were generated over time and cracks were healed.

Self-Healing Properties of Fiber-Reinforced Cement Composite (FRCC) Depending on Various Curing Conditions (양생조건에 따른 섬유보강 시멘트계 복합재료(FRCC)의 균열 자기치유 특성)

  • Choi, Heesup;Choi, Hyeonggil
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.4
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    • pp.289-296
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    • 2016
  • In this study, the self-healing effect of a fiber-reinforced cement composite (FRCC) was examined using a drying-wetting test and an outdoor exposure test. The influence of various curing conditions on the self-healing effect of the FRCC was also investigated. The effect of self-healing was evaluated using a permeability coefficient and by investigating the cracks using a optical microscope. The results confirmed that the FRCC was capable of self-healing under a long wetting time and a low drying temperature. In addition, watertight performance by self-healing was shown to have a significant influence on wetting time. Meanwhile, this self-healing effect was enhanced by hydration as a result of rainfall when the FRCC was put under actual environmental conditions. Moreover, it was determined that cracking self-healing can be improved by using the appropriate admixture materials.

Influence of Exposure Environmental Conditions on the Crack Healing Performance of Self-healing Repair Mortar Specimens (노출환경 조건이 자기치유형 보수 모르타르 시험체의 균열 치유성능에 미치는 영향)

  • Lee, Woong-Jong;Lee, Hyun-Ho;Ahn, Sang-Wook;Lee, Kwang-Myong
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.4
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    • pp.283-288
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    • 2018
  • Since the crack self-healing materials are activated according to the exposure environmental conditions from the time of crack occurrence, it is very important to clarify the relationship between the healing performance and the exposure environmental conditions of the crack surface. In this paper, the influence of the exposure environmental conditions on the crack healing performance of self-healing repair mortar was investigated through the water permeability test. The influence of temperature and humidity on the crack width of cracked specimens was evaluated. As a result of measuring the change of the crack width, the effect of curing temperature was negligible but it was confirmed that crack-closing occurred due to the change of dry-wet condition. The healing materials produced on the crack surface of the specimens was identified as calcite minerals. Since the minerals with high density are precipitated under the influence of gravity, the healing performance is somewhat different according to the direction of the crack surface, and the healing performance was significantly improved in the wet exposure condition than the air exposure condition.

An Experimental Study on the Quality and Crack Healing Characteristics of Repair Mortar Containing Self-Healing Solid Capsules of Crystal Growth Type (결정성장형 자기치유 고상캡슐을 혼합한 보수 모르타르의 품질 및 균열 치유 특성에 관한 실험적 연구)

  • Oh, Sung-Rok;Kim, Cheol-Gyu;Nam, Eun-Joon;Choi, Yun-Wang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.1
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    • pp.59-66
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    • 2020
  • In this study, self - healing solid capsules of crystal growth type which can be mixed directly with repair mortar were prepared, and the quality and crack healing performance of repair mortar with self - healing solid capsules were evaluated. The table flow and the air flow rate of the repair mortar material mixed with self-healing solid capsules were found to have no significant influence on table flow and air volume regardless of mixing ratio. Compressive strength tended to decrease with increasing capsule mixing ratio. As a result of evaluation of crack healing properties according to constant water head permeability test, initial water permeability decreased, and reaction products were generated over time and cracks were healed.

Importance of Impregnation and Polishing for Backscattered Electron Image Analysis for Cementitious Self-Healing Specimen (시멘트계 자기치유 시편에 대한 반사전자현미경 이미지 분석을 위한 함침과 연마의 중요성)

  • Kim, Dong-Hyun;Kang, Kook-Hee;Bae, Seung-Muk;Lim, Young-Jin;Lee, Seung-Heun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.4
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    • pp.435-441
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    • 2017
  • Studies on self-healing have currently been diversified and the methods to evaluate the studies have become more diversified as well. Among them, the back-scattered electron (BSE) image acquired through the scanning electron microscope (SEM) is attempted as the means to evaluate the self-healing effect on cracks. In order evaluate by the BSE image, sophisticated pre-processing of specimen is critical and this injected inside the particle, pore and artificial crack of the hardener to stabilize the structure of the newly generated self-healing product and it enables to endure the stress on polishing without deformation. The impregnated specimen smoothen the surface to obtain the BSE image of high resolution that polishing is made for diamond suspension for wet polishing after dry polishing. As a result of evaluating the self-healing product on the impregnated and polished self-healing specimen, the generated product is formed from the surface of the artificial crack and the self-healing substances are confirmed as $Ca(OH)_2$ and C-S-H.

The Crack Healing Properties of Cement Mortar Materials Using Crystal Growth Type Self-Healing Solid Capsules According to the Crack Induction Age (균열 유도 재령에 따른 결정성장형 자기치유 고상캡슐 활용 시멘트 모르타르의 균열 치유 특성)

  • Choi, Yun-Wang;Nam, Eun-Joon;Kim, Cheol-Gyu;Oh, Sung-Rok
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.4
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    • pp.475-482
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    • 2020
  • In this study, three levels of solid capsules were prepared according to the composition ratio of core materials for the crystal growth type self-healing solid capsule, and a cement mortar was prepared with the crystal growth type self-healing solid capsule. The prepared solid capsule was mixed with 3% of the cement mass to evaluate the healing properties according to the crack induction age of the cement mortar. As a result of test, the crack healing properties according to the crack induction age of cement mortar mixed of solid capsules, it was confirmed that the self-healing performance of the cement mortar with the solid capsules was increased self-healing performance of 7 days than 28 days. This is because the unhydrated binder remains.

The Experimental Study on Preparation Characteristics of Self-healing Microcapsules for Mixing Cement Composites Utilizing Liquid Inorganic Materials (액상 무기재료를 활용한 시멘트 복합재료 혼합용 자기치유 마이크로 캡슐의 제조 특성에 관한 실험적 연구)

  • Choi, Yun-Wang;Oh, Sung-Rok;Kim, Cheol-Gyu;Lim, Hak-Sang
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.4
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    • pp.236-244
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    • 2018
  • In this study, we tried to fabricate self - healing microcapsules using liquid inorganic materials which can be mixed directly with cement composites. The basic properties of the liquid inorganic material were evaluated and microencapsulation was performed. The focus of this paper is on the quality and manufacturing characteristics of cement composites rather than the healing effects of self - healing microcapsules according to mixed capsules. Test results, the self-healing microcapsules encapsulate liquid inorganic material which is stable at room temperature and has high crack followability, and the yield is over 90%. The size of self - healing microcapsule was able to change according to the synthetic agitation speed and it was able to secure more than 70% of target size. In addition, the loss of less than 10% was found to occur through the membrane strengthening of self - healing microcapsules, and it could be reduced by 50% compared with the case without membrane strengthening.

Crack Self-Healing Performance According to Absorption Test of Fiber Reinforced Concrete (콘크리트의 흡수율에 따른 균열 자기치유 성능)

  • Woo, Hae Sik;Park, Byoung Sun;Yoo, Sung Won;Choi, Young Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.2
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    • pp.122-129
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    • 2019
  • Cracks in concrete structures are inevitable phenomena caused by shrinkage, hydration heat, and external loads. These cracks facilitate the penetration of external harmful ions into the concrete, which greatly reduces its durability. Recently, self-healing concrete has been actively studied. Also, self-healing fiber-reinforced concrete have been studied to control the crack in concrete and to maximize the shelf-healing capability. In this study, mortar specimens containing PVA fiber, fly ash and crystalline admixture were fabricated. The compressive and flexural strength were evaluated. Also, the self-healing performance was evaluated by the absorption test. From the results, it was confirmed that the amount of water absorbed by healing of the crack decreased as time increased. It was also found that PVA fiber is beneficial for the production of calcium carbonate, an additional healing product.

Self Healing System for Concrete Surface Crack using Polymer based Coating Agent Incorporating Microencapsulated Healing Agent (마이크로캡슐을 함유한 폴리머 코팅제의 콘크리트 표면균열 자기치유시스템)

  • Shin, Ki-Su;Ryu, Byung-Chul;Wang, Xiao-Yong;Park, Ki-Bong
    • Journal of the Korea Institute of Building Construction
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    • v.15 no.6
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    • pp.579-587
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    • 2015
  • In this paper, microencapsulated healing agent was embedded in the polymer matrix to obtain self healing properties. Microencapsulation of methacrylate using polyurea-formaldehyde as a shell material and studied the effect of agitation rate on capsule characteristics such as size, shell thickness, and surface morphology. The formation of microcapsules was confirmed by FTIR and TGA, and capsule characteristics were studied by optical microscopy and SEM. The self-healing effect was evaluated using permeability measurements and further confirmed by surface analytical tools including optical microscope. According to the experimental results, the microencapsulated healing system has the self-heaing ability for artificial cracks.