• 한국콘텐츠학회논문지
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• 제15권9호
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• pp.384-394
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• 2015

본 연구에서는 원통형 지르코니아 코어에 다섯 종류의 지르코니아 비니어 세라믹을 축성하여 push-전단결합강도를 측정하고, 비니어 세라믹의 이축굽힘강도와 지르코니아 글라스 라이너 처리에 따른 전단결합강도 차이를 알아보고자 하였다. 지르코니아 비니어 세라믹은 piston-on-three-ball test로 이축굽힘강도를 측정하였고, 지르코니아 실린더 코어와 비니어 세라믹은 push-shear test로 결합강도를 측정하였으며, 결과값은 이원분산분석을 사용하여 분석하였다. 이축굽힘강도는 Cercon ceram kiss (CE)군에서 가장 높게 측정되었고 전단결합강도는 글라스 처리군과 Triceram(TR)군이 높게 측정 되었으며 Creation ZI(CR)군에서 가장 낮은 값이 측정 되었다. 실험군에서 지르코니아 라이너 처리군이 라이너 처리하지 않는 군보다 전단결합강도가 높게 나타났으며 통계적으로 유의한 차이를 보였다(P<0.05). 따라서 지르코니아 라이너 처리는 지르코니아와 비니어 세라믹의 결합강도를 향상시킬 수 있는 것으로 사료된다.

• 한국강구조학회 논문집
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• 제29권5호
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• pp.377-387
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• 2017

이 연구에서는 강판 매입형 합성기둥의 Push-out Test를 통해 강재와 콘크리트의 부착면적에 따른 영향을 알아보았다. 이로써 부착면적이 넓을수록 부착응력은 작아진다는 경향이 조사되었다. 또한 소규모 매입형 합성기둥의 경우에는 설계기준에서 제시하는 공칭부착 응력값이 과소하게 적용되는 것을 확인하였다. 다음으로 H형강 매입형 합성기둥의 Push-out Test를 통해 전단연결재의 수와 간격에 따른 영향을 알아보았다. 이로써 전단연결재의 전단거동을 파악할 수 있었다.

• Steel and Composite Structures
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• 제42권2호
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• pp.191-207
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• 2022

Undoubtedly, the employment of direct bond interaction between steel and concrete is preceding the other mechanisms because of its ease of construction. However, the large scatter in the experimental data about the issue has hindered the efforts to characterize bond strength. In the following research, the direct bond interaction and bond-slip behavior of CFTs with circular cross-section were examined through repeated load-reversed push-out tests until four cycles of loading. The influence of different parameters including the diameter of the tube and the use of shear tabs were assessed. Moreover, the utilization of expansive concrete and external spirals was proposed and tested as ways of improving bond strength. According to the results section dimensions, tube slenderness, shrinkage potential of concrete, interface roughness and confinement are key factors in a natural bond. Larger diameters will lead to a considerable drop in bond strength. The use of shear tabs by their associated bending moments increases the bond stress up to eight times. Furthermore, employment of external spirals and expansive concrete have a sensible effect on enhancing bonds. Macro-locking was also found to be the main component in achieving bond strength.

• 한국강구조학회 논문집
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• 제13권5호
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• pp.557-566
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• 2001

데크플레이트를 사용한 합성슬래브가 합성거동을 발휘하기 위해서는 데크플레이트와 콘크리트의 부착강도가 확보되어야한다. 합성슬래브에서 전단부착강도는 콘크리트와 데크플레이트의 화학적 부착력, 마찰저항 기계적 상호작용에 의해 발생한다. 또 기계적 상호작용은 길이 방향 전단력 전달 장치인 엠보싱 및 쉬어코넥터, 데크플레이트 형상 등에 의해서 확보되어 진다. 그리고 기계적 상호작용의 효과는 상호 접착부의 수직박리를 구속할 수 있는 데크의 형상과 쉬어코넥터 설치에 따른 단부정착 여부에 따라 크게 달라진다. 그러므로, 본 연구에서는 폐쇄형 데크플레이트에 대하여 기계적 전달장치인 엠보싱과 쉬어 코넥터로 사용되는 스터드 볼트에 대한 전단 보강장치의 부착효과를 Push-off 실험을 통하여 규명하였으며 이들 인자들에 대하여 제안식을 제시하였다. 이는 합성슬래브 설계방법의 기초자료로 이용될 수 있을 것으로 사료된다.

• 대한치과기공학회지
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• 제35권1호
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• pp.19-27
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• 2013

Purpose: The aim of this research was to evaluate the shear bond strength of different zirconia veneering ceramics with and without liner glass materials to yttria partially-stabilized tetragonal zirconia polycrystalline(Y-TZP). Methods: Five co mmercial zirconia veneering ceramics were used in this study, E-Max(EM), Creation ZI(CR), Cercon ceram kiss(CE), Triceram(TR) and Zirkonzahn ICE(ZI). All samples were prepared according to manufacturer's instructions. Experimental industrially manufactured Y-TZP ceramic blocks(diameter: 2.7 mm; height: 13.5 mm) were used in this study. Shear bond strength between zirconia ceramic coping and zirconia veneering ceramics were evaluated by the push-shear bond test. The fracture load data were analyzed using ANOVA and Scheffe's test(${\alpha}$=0.05). The fractured surfaces of zirconia core ceraimc and zirconia veneering ceramics were observed using a scanning electron microscope(SEM). Results: The mean shear bond strengths ranged from 20 MPa ($20.12{\pm}6.34$ MPa) to 66.6 MPa ($66.62{\pm}10.01$ MPa). The Triceram(TRG) showed the highest value and Creation ZI(CR) showed the lowest value. In all groups, Zirconia liner and glass material groups was significantly higher shear bond strength than without liner(P<0.05), with the exception of Cercon ceram kiss(CE)groups. Conclusion: Zirconia bonding materials may have the advantage of improved bond strength between zirconia ceramic core and veneering ceramics.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.770-773
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• 2004

The full-width, full-depth precast panel system is very efficient for the rehabilitation of deteriorated decks as well as for new bridge construction.. The horizontal bond strength at the interface between the two interconnected elements is of primary importance in order to achieve composite action. The strength of the bond between the two precast members should be high enough to prevent any progressive slip from taking place. However, the case when both of the interconnected elements are precast members bonded by means of grout, is not currently addressed by KBDC or AASHTO. This is the main impetus for this study. A total 43 push-off tests were performed to evaluate the horizontal bond strength and to recommend the best practice for the system. Test parameters included different interface surface conditions, different amount and different types of shear connectors. The presence of the shear keys at the top surface of the beam increased the interface bond capacity tremendously compared to the bond capacity with a different surface conditions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.240-243
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• 2004

A new shear connection for the application of precast decks to PSC girders was proposed and push-off tests were conducted to evaluate the horizontal shear strength of the shear connection. Major parameters of the tests were connector type, shank area, vertical load, surface condition and bedding height. Judging from the test results, shear strength of the suggested shear connection was proportional to the shank area and yield strength of the connectors and was in inverse proportion to the bedding height. Shear connection with shear key at the surface showed better performance. An empirical equation for the evaluation of the shear strength of the shear connection without considering bond strength was proposed and it showed good correlation with the test results.

• 대한치과교정학회지
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• 제23권1호
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• pp.75-88
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• 1993

Recent reports indicate that shorter etching times than 60 seconds can be adopted without affecting the bond strength and clinical disadvantages. The purpose of this in vitro study was to compare the shear bone strength and to measure depth of etch at different etching time length. One hundred and eight extracted bovine lower central incisors were embedded each in a tooth cup with cold-cure acrylic resin. The facial surfaces of the teeth were ground wet with 600-, 800-, 1000-, and 1200-grit Sic papers, and finally polished with a water slurry of extrafine silicon carbide powder, washed with tap water, and dried with hot air. Nine groups of nine prepared teeth were etched with a commercial($38\%$ phosphoric acid solution) for 0, 5, 10, 15, 20, 30, 60, 90, and 120 seconds, respectively, rinsed with tap water, and dried with hot air. One conditioned teeth from every group was selected randomly for the scanning electron microscopic examination, and the remaining eight teeth of the groups were used for measuring the push shear bond strength after bonding brackets and immensing them in the $36.5^{\circ}C$ water for 24 hours. Another nine groups of three teeth were used for measuring the depth of etch and surface roughness with a surface profilometer. after pieces of adhesive tape of 3mm inner diameter positioned on the ground enamel surfaces, and etched with the above mentioned. The data obtained form the above expeiments were analysed statistically with one way ANOVA and Dunkan's multiple range test with the $95\%$ confidence level. The results and conclusion of the study were as follows; 1. The results of shear bond strength for the given experimental etching times were not statistically different, but showed the tendency of decreasing shear bone strength after over 60 seconds etching times. 2. On the scanning election microscopic examination, it was observed that the morphological patterns of etched enamel surface for 5 to 20 seconds were similar and consitent, and those for 30 to 120 seconds showed increasing over-etched patterns depending on the length of etching times. 3. The depth of etch was increased almost proportionally by the length of etching times, but it was not associated with the shear bond strength. 4. The surface roughness increased depending on the length of etching times, but it was not associated with the shear bond strength. 5. This experiment indicated that proper etching time with $38\%$ phosphoric acid solution is in the range of 5 to 30 seconds.

• Steel and Composite Structures
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• 제38권5호
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• pp.563-582
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• 2021

The present study experimentally and analytically investigated the push-out behaviour of H-shaped steel section embedded in ultrahigh-performance fibre-reinforced concrete (UHPFRC). The effect of significant parameters such as the concrete types, fibre content, embedded steel length, transverse reinforcement ratio and concrete cover on the bond stress, development of bond stress along the embedded length and failure mechanism has been reported. The test results show that the bond slip behaviour of steel-UHPFRC is different from the bond slip behaviour of steel-normal concrete and steel-high strength concrete. The bond-slip curves of steel-normal concrete and steel-high strength concrete exhibit brittle behaviour, and the bond strength decreases rapidly after reaching the peak load, with a residual bond strength of approximately one-half of the peak bond strength. The bond-slip curves of steel-UHPFRC show an obvious ductility, which exhibits a unique displacement pseudoplastic effect. The residual bond strength can still reach from 80% to 90% of the peak bond strength. Compared to steel-normal concrete, the transverse confinement of stirrups has a limited effect on the bond strength in the steel-UHPFRC substrate, but a higher stirrup ratio can improve cracking resistance. The experimental campaign quantifies the local bond stress development and finds that the strain distribution in steel follows an exponential rule along the steel embedded length. Based on the theory of mean bond and local bond stress, the present study proposes empirical approaches to predict the ultimate and residual bond resistance with satisfactory precision. The research findings serve to explain the interface bond mechanism between UHPFRC and steel, which is significant for the design of steel-UHPFRC composite structures and verify the feasibility of eliminating longitudinal rebars and stirrups by using UHPFRC in composite columns.

• 한국공간구조학회논문집
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• 제19권4호
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• pp.53-60
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• 2019

In this study, an experimental study was carried out to evaluate the bond shear performance according to the shear connector between the glue-laminated timber and steel interface. Ten block shear specimens were fabricated according to the configuration of the adhesive surface of wood and steel. In addition, four test specimens were produced according to the main variable shape of the wood-concrete shear connector. As a result of the block shear test, the shear strength of the steel-wood adhesive is shown to have a shear performance greater than the wood-wood shear strength. As a result of the push-out test according to the shape of the shear connector, the shear strength increased linearly with the attachment area. The complete composite behavior between the glued-laminated timber and the steel can be secured.