• Advances in concrete construction
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• 제7권3호
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• pp.191-201
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• 2019

Bamboo concrete bond behaviour is investigated through pullout test in this work. The bamboo strip to be used as reinforcement inside concrete is first treated with chemical adhesive to make the bamboo surface impermeable. Various surface coatings are explored to understand their water repellant properties. The chemical action at the bamboo concrete interface is studied through different chemical coatings, sand blasting, and steel wire wrapping treatment. Whereas mechanical action at the bamboo concrete interface is studied by developing mechanical interlock. The result of pullout tests revealed a unique combination of surface treatment and grooved bamboo profile. This combination of surface treatment and a grooved bamboo profile together enhances the strength of bond. Performance of a newly developed grooved bamboo strip is verified against equivalent plain rectangular bamboo strip. The test results show that the proposed grooved bamboo reinforcement, when treated, shows highest bond strength compared to treated plain, untreated plain and untreated grooved bamboo reinforcement. Also, it is observed that bond strength is majorly influenced by the type of surface treatment, size and spacing of groove. The changes in bamboo-concrete bond behavior are observed during the experimentation.

• Advanced Composite Materials
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• 제16권4호
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• pp.259-267
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• 2007

Mechanical reinforcement of an all-sustainable composite, composed of papyrus stem-milled particles as reinforcement and poly-L-lactic acid (PLLA) resin as matrix, was investigated. The papyrus particles (average diameter of $70{\mu}m$) could be well dispersed in PLLA resin up to 50 wt% without any surface modification. Young's modulus of the composite was 4.2 GPa at 50 wt% of the papyrus content. This is a two-fold increment in modulus as compared to that of the PLLA matrix. The tensile strength of the composite was almost constant around 48 MPa irrespective of the papyrus content. Temperature dependence of the storage modulus demonstrated that the incorporation of papyrus restricts the large drop in the modulus above the glass transition of PLLA.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.828-835
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• 2000

In recent years, RC structures need reinforcement due to physical and chemical deterioration, reduction of serviceability and structural capacity. For reinforcement of RC structures, steel plate attachment, area increase and composite fiber sheet attachment methods are used, but there are some problems like weight increase, workability, quality control and fire resistance capacity. This study presents the effectiveness of flexural reinforcement of RC beams using composite rods that are inserted in high strength special purposed polymer mortar.

• 한국지반환경공학회 논문집
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• 제20권8호
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• pp.13-20
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• 2019

지반보강을 위해 국내에서 널리 사용되고 있는 공법으로 약액주입공법, 앵커공법, 소일네일공법 및 마이크로파일공법 등을 들 수 있다. 이러한 지반보강공법은 보강재의 종류, 설치방법, 프리스트레스의 유무 및 그라우팅 방법에 따라 다양한 공법으로 개발되고 있으나, 공통적으로 지반보강재의 강성, 그라우트와 보강재의 마찰력 및 그라우트와 지반의 마찰력이 주요 설계변수이다. 따라서, 최적화된 지반보강재는 보강재 자체의 인장강도가 큰 재료로써 보강재와 그라우트사이의 마찰력이 크며, 그라우트와 지반사이의 마찰력을 향상시킬 수 있는 최적의 그라우팅 방법의 적용이 필요하다. 이에, 본 연구에서는 보강재의 형상과 그라우팅 방법에 따른 보강효과를 평가하고자 총 20여개의 실내모형실험을 실시하였으며, 실험결과 타공+날개보강형과 포스트그라우팅 방법이 보강 효과가 가장 우수한 것으로 나타났다.

• 한국세라믹학회지
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• 제40권7호
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• pp.625-631
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• 2003

Recent work at USC has focused on strategies to enhance the toughness and overall mechanical performance of polymer foams for use in lightweight sandwich structures. Both mechanical and chemical approaches have been employed with reasonable success. Fiber reinforcement, though difficult from a processing perspective, can lead to substantial enhancements in toughness and strength, while reducing friability. Chemical modifications are also challenging from a processing perspective, but can produce similar enhancements in performance. Efforts to enhance performance of phenolic foam and PVC foam through fiber reinforcement and chemical modification are described, along with the resulting enhancements in performance.

• 대한화학회지
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• 제60권3호
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• pp.177-180
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• 2016

The surface properties of carbon microfibers (CMFs) are modified by chemical deposition of carbon nanofibers via the so-called ethylene processing. CMFs and the modified CMFs (MCMFs) are investigated as reinforcement additives to fabricate polyethylene (PE) composites with enhanced mechanical characteristics. The mechanical properties of the PE-MCMF composites are found to be better and favorable for applications under harsh climatic conditions such as those in Siberia. Improved adhesive interaction between MCMFs and PE is responsible for these enhanced mechanical properties.

• 한국구조물진단유지관리공학회 논문집
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• 제18권1호
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• pp.75-83
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• 2014

콘크리트의 취성파괴를 방지하기 위해 강섬유 보강재는 효과적인 복합재료이다. 그러나 시멘트 사용량이 많아지면 건조수축이 증가하고 이로 인해, 강섬유 보강재의 연성증가 효과가 제한될 수 있다. 팽창재를 사용한 콘크리트 내부의 강섬유 보강재는 화학적 프리스트레싱 효과가 발생하여 강섬유 보강효과를 증가시킬 수 있다. 본 연구에서는 CSA 팽창재와 강섬유 보강재를 혼입하여 콘크리트의 역학적인 특성을 분석하였다. 체적비 1~2%의 강섬유 보강재와 시멘트 중량의 10%의 CSA 팽창재를 혼입하였으며, 다양한 역학적 특성과 휨거동을 분석하였다. 강섬유 보강재를 혼입한 CSA 콘크리트는 인장강도와 초기균열강도의 증가를 나타냈으며, 균열후의 파괴에너지 증가와 같은 연성거동을 뚜렷하게 나타내었다. 적절한 팽창재 사용과 최적의 강섬유 보강재의 혼입률이 도출된다면 이들의 상호작용은 콘크리트의 취성을 더욱 효과적으로 제어할 수 있다.

• 한국농촌건축학회논문집
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• 제21권4호
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• pp.45-52
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• 2019

Chemical grouting method is mainly used for construction of dams and reservoirs, stabilization and reinforcement of slopes, reinforcement of soft grounds such as embankments, dredging and landfills, the order of earthquake response method, and the reinforcement of structures. Recently, it is widely applied in construction sites such as highways, airfields, high-speed railways, subsea facilities, port construction works, tunnels, and subway works. As such, the demand for grouting continues to increase. The development of the grouting method was focused on increasing the strength of the ground, and the development of the chemical additives, the injection device, and the stirring device were mainly performed. But ordinary portland cement used for grouting is a product that consumes natural resources such as limestone, generates a large amount of greenhouse gases, consumes a large amount of energy sources, and it is time to develop products and new methods to replace them. In this study, Ordinary Portland Cement and New Grouting Binder (circulating fluidized bed boiler fly and blast furnace slag) were compared and analyzed by the following test. Homo-gel strength and homo-gel time, water quality analysis of the water used and soil contamination process tests of homo-gel samples were performed. In the case of NGB, when Using water is used as the reservoir water, the strength measured smaller than that of the other water. However, it shows about 2.5 times greater than the homo-gel compressive strength applied to OPC (7-day, reservoir water), so there is no problem with water quality when applied.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.106-106
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• 2003

6 woven geotextiles for reinforcement were used to examine the effects of weatherability and reduction factor on the tensile properties. Decrease of tensile strength as the tool of these evaluations of woven geotextile was examined.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.293-300
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• 1999

The maintenance for the stability of tunnel, especially on downtown area, careful check must be considered during construction stage and after. Moreover we have to achieve the stability of tunnel by ground improvement and reinforcement when ground condition is bad or tunnel failures under the various ground conditions. In this paper, it is presented the case of tunnel failure and the state of restoration by ground reinforcements at seoul subway $\bigcirc$-$\bigcirc$ construction site. For the purpose of ground reinforcement, first, curtain wall was established by chemical grouting. Secondly, cement milk grouting was carried by upper part of tunnel crown. Also Boreholes loading test and tunnel monitoring were carried by in failure site for the long term stability of tunnel.