• 폴리머
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• 제38권6호
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• pp.820-826
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• 2014

본 연구에서는 styrene(St)와 butyl acrylate(BA)를 단량체로 폴리머를 합성하여 폴리머 필름의 인장강도를 측정하고 폴리머 시멘트 모르타르로 제작하여 세공구조와 부착강도, 그리고 인장강도와의 상호 연관성을 파악하고자 하였다. 본 연구결과 St/BA 폴리머 필름의 인장강도는 St의 함유량이 높을수록 증가하는 것으로 나타났으며. 폴리머 시멘트 모르타르의 부착강도와 인장강도는 폴리머 필름의 인장강도가 클수록, 미세공극량이 많을수록 우수하게 나타나고 있다.

• Structural Engineering and Mechanics
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• 제41권3호
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• pp.379-393
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• 2012

Of the various methods of splicing reinforcing bar in reinforced concrete structure, mortar-filled sleeve reinforcement splice offers diverse benefits, not only in terms of structural performance but also for the construction process. Consequently, after the mortar-filled sleeve splices have been developed in recent years, research and development on these splices has been actively carried out, in order to evaluate its macro structural performance, such as its strength and stiffness, with the aim of enabling this system to be applied to construction in the field as early as possible. However, to make a proper evaluation on the overall structural performance of the mortar-filled sleeve reinforcing bar splice, it is of critical importance to understand the lateral confining action of the sleeve, which is known to affect the bond strength between the embedded bar and mortar in the sleeve. Accordingly, in this study, an experiment of monotonic loading and cyclic loading was conducted with a full-sized mortar-filled sleeve splice attaching strain gauges on the sleeve surface with experimental variables such as development length of bar, etc. Based on the test results, the effect of the lateral confining action of the sleeve was analyzed and considered in terms of the bond strength between the bar and mortar in this splice.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.853-858
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• 2000

According to the results of this research, Production of Fold Mortar Permanent - Form was found to be possible by Mortar. Th FP-Form (Fold Permanent-Form) mortar had compress strength 580kgf/$\textrm{cm}^2$. FP-Form model was made by the result of the first research. There was no minute-crack on beam form and the outer surface of form was very smooth, and those qualities it were made possible hand-mad by experiment. This study is about bond strength progress of FP-Form that developed for the form work rationalization and systematization. The result of this study follows; (1) Fluidity and strength development of mortar which used for FP-Form are satisfied (2) After study on getting good bond strength progress, inside-uneven type presents the better suitableness, and wire netting V-type presents the better shear strength.

• 대한토목학회논문집
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• 제31권2A호
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• pp.137-143
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• 2011

본 연구는 섬유보강 시멘트 모르타르에서 무수말레인산이 그라프트된 폴리프로필렌(maleic anhydride grafted polypropylene, mPP) 분말의 첨가가 무극성 마크로 합성섬유(마크로 합성섬유)의 부착특성에 미치는 효과를 평가하였다. 다양한 mPP의 첨가율(시멘트 중량의 0%, 5%, 10%, 15%, 20%, 25%, 30%)에 따른 시멘트 모르타르와 마크로 합성섬유의 부착거동을 평가하기 위하여 Dog-bone 부착시험을 수행하였다. 시멘트 모르타르내에서 마크로 합성섬유의 부착 특성(일반거동, 인발하중 및 계면인성)은 mPP의 사용량 증가할수록 증가하였다. 인발시험 후 마크로 합성섬유 표면의 미세구조 분석은 mPP의 첨가율에 따른 마찰 저항력을 평가하기 위하여 관찰하였다. mPP의 첨가율이 증가할수록 마크로 합성섬유 표면에 긁힘 현상이 증가하였다.

• Advances in concrete construction
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• 제6권3호
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• pp.285-296
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• 2018

In the present paper, the results of an experimental study of the bond between repair materials and mortar substrate subjected to hot climate is presented. Half-prisms of size $40{\times}40{\times}80mm$, serving as a substrate mortar samples (SUBM) were manufactured in the laboratory and then stored at an ambient temperature for 6 months. Five self compacting mortar mixes (SCMs) incorporating 0%, 10%, 20%, 30%, and 40% of natural pozzolana as white cement replacement were used as repair materials. Repaired composite samples (SCMs/SUBM) were cured at hot climate for different lengths of time (28 and 56-days). During the first week of curing, the composite samples were watered twice a day. The test carried out to assess the bond between SCMs and SUBM was based on three-point bending (3 PB) test. The obtained results have proved that it was feasible to produce compatible repair materals in this curing environment by using up to 30% natural pozzolana as white cement replacement.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.238-239
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• 2014

It is well known that the bond characteristics of fiber govern the performance of fiber reinforced composite material. A preliminary study was carried out to investigate the pull-out behavior of amorphous and conventional single fiber in cement mortar in accordance with the JCI(Japan Concrete Institute) SF-8. The test was performed under displacement control, and results showed that the bond strength decreased with increasing fiber length. In addition, the amorphous steel fiber showed much higher pull-out load per unit weight compared to conventional steel fiber.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.519-526
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• 1997

The purpose of this study is to develop the analytical model for the reinforcement bar connection in group-filled steel pipe sleeve, which consists of beam elements for the reinforcement bar and shell elements for the sleeve and the mortar and spring elements for the bond stress-slip relationship. In the reinforcement bar connection using grout-filled steel pipe sleeve, the major variables are the bond stiffness between reinforcement bar and mortar($K_1$) and between sleeve and mortar($K_2$). It is nearly difficult to predict the exact bond stiffness with the experimental results. Therefore, The linearly elastic analyses using ABAQUS, FEM package show the validity of the mathematical equations for the bond stiffness and the choice of material elements in this paper. To predict the behaviour between yield and ultimate tensile strength, the nonlinear analyses must be performed henceforth.

• Structural Engineering and Mechanics
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• 제17권2호
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• pp.141-152
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• 2004

The bonding behaviors of Lightweight Aggregate Concrete (LWAC) and normal weight concrete were investigated experimentally. Pull-out tests were carried out to measure the bond strengths of three groups of specimens with compressive strength levels of 60, 40, and 20 MPa, respectively. Test results showed that the difference in the bond failure pattern between LWAC and normal weight concrete was significant as the concrete compressive strength became lower than 40 MPa. The corresponding bond strengths of LWAC were lower than that for normal weight concrete. As the compressive strength of concrete became relatively high (> 40 MPa), a bond failure pattern in normal weight concrete occurred that was similar to that in LWAC. The bond strength of LWAC is higher than that for normal weight concrete because it possesses higher mortar strength. Stirrup use leads to an increase of approximately 20% in nominal bond strength for both types of concrete at any strength level.

• 한국구조물진단유지관리공학회 논문집
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• 제15권5호
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• pp.169-177
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• 2011

본 연구에서는 충격하중에 유리한 층 구조를 갖는 패각의 구조를 채용한 콘크리트 분절 복합체의 충격하중 성능을 평가하였다. 콘크리트 분절 복합체의 성능을 향상시키기 위해서는 콘크리트 블록 사이의 모르타르의 부착강도가 개선되어야 한다. 따라서 본 연구에서는 모르타르의 부착강도를 향상시키기 위해 폴리머 모르타르를 적용하였다. 부착강도 실험에 따라 15% 라텍스 모르타르를 선정하였고, 일반 모르타르와 라텍스 모르타르를 적용한 부재에 대한 정하중 및 저속 충격하중 실험을 수행하였다. 실험 결과 모르타르의 부착력이 향상된 분절복합체가 높은 충격하중 저항 능력을 보였다. 불연속 균열 모델을 이용한 비선형 유한요소해석과 충격하중 실험의 결과와 충격에너지 소산도가 유사하게 나타났다. 따라서 분절복합체 해석 모델의 개선을 통해 다양한 변수의 충격 저항 능력의 예상과 평가가 가능할 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.203-208
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• 1999

The purpose of this study is to examine the bond properties of polymer cement mortar. Generally, cement mortar using polymer has been used that recovering the deteriorative concrete structure performance. In this case, it is very important problem to become a monolithic construction by bonding property. In this study, it is evaluated with other properties that adhesion strength between polymer cement mortar and concrete substrate. And polymer cement mortar was compared with plain cement mortar by scanning electron microscope.