• Title/Summary/Keyword: 보수모르타르

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An Experimental Study on the Bond Strength of Polymer-Modified Mortars (폴리머 시멘트 모르타르의 부착강도에 대한 실험적 연구)

  • Park, Hun-Il;Song, Ki-Min;Park, Sang-Sun;Sin, Hong-Chul;Sin, Ju-Jae;Kim, Young-Kun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.629-632
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    • 2008
  • In the concrete repairing industry, it's very significant to apply adequate repair materials and construction method in order to extend service life of deteriorated concrete structure efficiently. also, adequate diagnosis of deteriorated structure's status should be involved. This paper describes an investigation of bond strength of polymer modified mortar applied both old deteriorated concrete surface substrate and well cured new concretes. The purpose of this investigation is comparing how much the tensile bond strength on construction site is different from laboratory test results. in the results of investigation, most of sample tested in laboratory is in compliance with KS F 4042's specification. and most of results of construction site are not in compliance with the specification cause of low tensile strength of concrete's surface.

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Bonding Properties of Steel-reinforced Polymer Cement Mortar Evaluated by Pull-off Test and FEM Modeling (폴리머 시멘트 모르타르의 철근부착력 평가를 위한 인발실험과 모델링)

  • Park, Dong-Cheon;Yoneda, Nobutosi;Cho, Bong-Suk
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.3
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    • pp.216-222
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    • 2014
  • Chloride attack to reinforced concrete structures located in seaside can cause a serious problem of durability and maintenance during the service life. Corrosion of reinforced steel bars in concrete decreases the bond strength and finally causes the detachment of concrete cover. Polymer cement mortar is usually adopted to repair the deteriorated RC structures because of its strong bonding property. The recovered load-carrying capacity after the repair was simulated by non-linear FEM analysis. The properties of concrete, repairing materials, bonding materials and reinforced bar were used as input data. Four types of redispersible polymer powders were used as components of polymer cement mortar. Pull-off tests were carried out to examine the bond properties such as rigidity and strength. Effects of a corrosion inhibitor and the loss of reinforced bars due to the corrosion were also considered in this study. FEM modeling and analysis were conducted to propose the universal model. Physical bonding in the relationship between repair materials and steel reinforced bar is more dominant than chemical bonding.

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 about Behavior of a Repaired Underwater Structure with an Epoxy Fiber Panel and Polymer Mortar (에폭시 섬유판넬과 폴리머 모르타르로 단면보수된 수중구조물의 거동에 관한 실험적 연구)

  • Hong, Sung-Nam;Park, Jun-Myoung;You, Chung-Jun;Han, Kyoung-Bong;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.1 s.53
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    • pp.69-77
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    • 2009
  • An underwater structure is made to put with serious damage state by special environmental factors. If this damage phenomena persist, as for the structure, it is generated a structural serious problem because of the corrosion of a reinforcing bar and the loss of the concrete cut end. Repair work of an underwater structure is very harder than repair work in land, and it is actual that certification about a maintenance effect is uncertain. And the existing repair method is applied to a structure damaged with you without verification of a repair effect by a foreign reward and experience. In this study, a repair method about an underwater structure was proposed and observed a behavior characteristic and interface failure of an specimens. and comparison analyzed an effect of a proposed maintenance method.

A Study on the Mechanical Properties of Polymer Repair-Mortars with CFBC Ash (순환유동층 보일러애시를 활용한 폴리머 보수 모르타르의 역학적 특성에 대한 연구)

  • Kang, Yong Hak;Lim, Gwi Hwan;Shin, Dong Cheol;Choi, Young Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.5
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    • pp.127-132
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    • 2018
  • The amount of generated Circulating Fluidized Bed Combustion ash (CFBC ash) is annually increasing, but most CFBC ash has been landfilled and discarded due to the limited utilization. The major chemical compositions of CFBC ash are $SiO_2$, CaO and $CaSO_4$, which could form hydration products by reacting with water as self-cementing property such as cement. The purpose of the this study is to derive the optimal mix proportions to improve polymer-modified mortar with the use of CFBC ash which has the self-cementing property. In order to develop polymer-modified mortar, three mix proportions were determined, and fundamental properties for the mixtures were obtained. As a result, the optimal mixture containing 10 percent of silica fume, 1.0 percent of polymer and 3.5 percent of expansive additives were proposed in this study.

Mechanical and Repair Performance of Sprayed Ductile Fiber Reinforced Cememtitious Composite(ECC) (습식스프레이공법으로 타설된 고인성 섬유보강 모르타르(ECC)의 역학적 특성과 보수 성능)

  • Kim, Yun-Yong
    • Journal of the Korea Concrete Institute
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    • v.15 no.3
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    • pp.462-469
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    • 2003
  • This paper presents an experimental study on the potential durability enhancement of infrastructures repaired by a sprayed high ductile fiber-reinforced cementitious composite (ECC). For this study, a PVA-ECC which exhibits sprayable properties in the fresh state and tensile strain-hardening behavior in hardened state was sprayed and tested. The experimental results show that the sprayed ECC exhibits mechanical properties with strain capacity comparable to the cast ECC with the same mix design. During loading, the crack widths of ECC are tightly controlled with an average of 30${\mu}m$. It is also revealed that when sprayed ECC is used as a repair material, ductility represented by deformation capacity at peak load of repaired beams in flexure are obviously increased in comparison to those of commercial prepackaged mortar (PM) repaired beams. In addition to high delamination resistance, the significant enhancement of energy absorption capacity and crack width control in ECC repair system suggest that sprayed ECC can be effective in extending the service life of rehabilitated infrastructures.

Flexural Strength and Durability Evaluation by Freezing and Thawing Test of Repaired Reinforced Concrete Beams (보수보강을 실시한 철근콘크리트 보의 동결융해시험을 통한 휨강도 및 내구성 평가)

  • Lee, Chang-Hyun;Eo, Seok-Hong
    • The Journal of the Korea Contents Association
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    • v.18 no.11
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    • pp.455-461
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    • 2018
  • This paper presents experimental investigations about flexural strength and durability of reinforced concrete beams repaired using ductile fiber reinforced cementitious composite (DFRCC) and carbon fiber sheet through freezing and thawing test. Total 14 RC beams of $100{\times}100{\times}400mm$ size were tested by 3-point bending and freezing and thawing test by KS F 2456. The beams were reinforced using 3D10 steels on both the tensile and compressive sides, and repaired on 3 sides expect on top cycle. Test results showed that the beams repaired using fiber carbon sheet revealed about 15% higher values of flexural strength compared than the cases of DFRCC motar. On the other hand, the results did not showed meaningful differences in the aspect of durability. For further research, consideration of the steel interference effect and real old specimens such as taken from real deteriorated structures are needed to be tested after repairing with DFRCC and carbon fiber sheet.

Basic Properties and Dimension Stability of Ultra Rapid Setting Cement Mortar Containing Low-Quality Recycled Aggregate (저품질의 순환골재를 혼입한 초속경 시멘트 모르타르의 기초물성 및 부피안정성)

  • Jeon, Sang-Min;Kim, Hyeong-Ki
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.3
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    • pp.246-252
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    • 2021
  • The basic properties and volume stability of the ultra-rapid setting cement mortar containing low-quality recycled aggregate with a higher water absorption and lower specific gravity than relavent Korea Standard were experimentally confirmed. The mix proportion without recycled aggregate followed that of the general repair mortar used in the fields. 15% and 30% of the fine aggregate was substituted by the recycled aggregate in the mixtures with and without latex emulsion, and properties and characteristics of the mortar including mortar flow, setting time, compressive and flexural strength, and linear deformation under sealed and unsealed conditions were evaluated. It was confirmed that when low-quality recycled aggregate was used by 30%, there were risks of decrease in the early-age strength by up to 50% within 24h and increases in drying shrinkage by up to 2 times for 2 weeks compared to the the mixtures without the recycled aggregate.

Experimental Study on the Use of High-Volume Fly Ash and Basalt Fiber as Emergency Repair Materials for Slope Stabilization: An Analysis of Basic Quality Characteristics (비탈면 긴급 복구를 위한 하이볼륨 플라이애시 및 현무암 섬유 보강 보수재료의 기초 품질 특성에 대한 실험적 연구)

  • Doo-Won Lee;Il-Young Jang
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.12 no.2
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    • pp.111-120
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    • 2024
  • This paper presents a study aimed at developing repair materials for emergency slope stabilization after disasters such as floods. The research assessed how different mix ratios of fly ash and reinforcement with basalt fibers affect the basic quality properties of mortars. Optimal amounts of fly ash were selected based on these properties, and appropriate amounts of chemical admixtures and thickeners were determined to enhance the quality attributed to the basalt fiber mixture. Notably, high-volume fly ash reduced the need for high-performance water reducers and improved workability, known benefits that also helped mitigate fiber ball issues in conjunction with the effects of thickeners. The experimental results indicated that the developed repair materials could potentially be used for emergency repairs, with a focus on initial age strength. This research aims to provide foundational data for repair materials used in future emergency slope stabilizations.

An Experimental Study on Rapid Repairing Mortar for Road with Steel Slag (철강 슬래그를 사용한 도로용 긴급보수 모르타르에 관한 실험적 연구)

  • Jung, Ui-In;Kim, Bong-Joo;im, Jin-Man;Kwak, Eun-Gu
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.5
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    • pp.419-427
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    • 2018
  • The purpose of this study is to recycle steel slag generated from the iron producing process and to use steel slag as a construction material which is currently landfilled Steel slag is subjected to aging treatment due to the problem of expansion and collapse when it reacts with water. The Slag Atomizing Technology (SAT) method developed to solve these problems of expanding collapse of steel slag. In this study, experimental study on the emergency repair mortar using the reducing slag, electric arc furnace slag and silicon manganese slag manufactured by the SAT method is Reduced slag was shown an accelerated hydration when it was replaced with rapidly-setting cement, and the rate of substitution was equivalent to 15%. It is shown that the electric furnace oxide slag is equivalent to 100% of the natural aggregate, and it can be replaced by 15-30% when the silicon manganic slag is substituted for the electric furnace oxide slag. With the above formulation, it was possible to design the rapidly repair mortar for road use. These recycling slags can contribute on achieving sustainability of construction industry by reducing the use of cement and natural aggregates and by reducing the generation of carbon dioxide and recycling waste slag.