• Title, Summary, Keyword: Bond Test

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A Study on Bond Strength between Fiber Sheet and Concrete for Concrete Surface Preparation and Heating Condition (콘크리트 표면처리와 가열조건에 따른 섬유쉬트와 콘크리트의 부착강도에 관한 연구)

  • Ahn, Sang-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.4
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    • pp.201-207
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    • 2002
  • An advanced fiber sheet has been widely used for strengthening of the concrete structures due to its excellent properties such as high strength and light weight. Bond strength is very important in strengthening the concrete structures using an advanced fiber sheet. This research examines the bond behavior between fiber sheet and concrete, investigates the bond strength by the direct pull-out test and the tensile-shear test. To obtain the tensile-shear strength a double-face shear type bond test is conducted. The primary test variables are the types of concrete surface roughness (disk-grinding/chipping) and retrofitting methods (bonding/injection). Thirty specimens were tested to evaluate the bond strength. It is shown that the average bond strength between fiber sheet and concrete by the direct pull-out test and the tensile-shear test is $22.3{\sim}23.1kgf/cm^2$ $17.92{\sim}19.75kgf/cm^2$, respectively.

IEEE 1500 Wrapper Design Technique for Pre/Post Bond Testing of TSV based 3D IC (TSV 기반 3D IC Pre/Post Bond 테스트를 위한 IEEE 1500 래퍼 설계기술)

  • Oh, Jungsub;Jung, Jihun;Park, Sungju
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.1
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    • pp.131-136
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    • 2013
  • TSV based 3D ICs have been widely developed with new problems at die and IC levels. It is imperative to test at post-bond as well as pre-bond to achieve high reliability and yield. This paper introduces a new testable design technique which not only test microscopic defects at TSV input/output contact at a die but also test interconnect defects at a stacked IC. IEEE 1500 wrapper cells are augmented and through at-speed tests for pre-bond die and post-bond IC, known-good-die and defect free 3D IC can be massively manufactured+.

Using scratch test to evaluate cohesive bond strength of Mo composite coating

  • Koiprasert, Hathaipat;Thaiwatthana, Sirinee;Sheppard, Panadda
    • International Journal of Advanced Culture Technology
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    • v.3 no.2
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    • pp.34-41
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    • 2015
  • Bonding strength of a thermal sprayed coating is difficult to measure using a conventional pull-off test method. Scratch test is a potential alternative testing method. An adhesive and a cohesive bond strength of the coating can be measured by the pull-off test while the scratch test performed on the cross-section of the thermal sprayed coating can only demonstrate the cohesive bond strength of the coating. Nevertheless, it is still beneficial to perform the scratch testing on the cross-section of the coating for the sake of comparison thus providing an alternative to the pull-off test. The scratch test method can reduce testing time and cost in the long run due to a significant cost reduction in consumables and energy and time saving from the curing step of the glue used in the pull-off test. This research investigates the possibility of using the scratch test to measure the cohesive bond strength of Mo/NiCrBSi composite coating. The results from the pull-off test and the scratch test indicate that the cohesive bond strengths of the Mo composite coating show similar trend and that the cohesive bond strength are increased when increasing NiCrBSi content.

Evaluation of Bond Strength Characteristic of Moisture Induced Asphalt Mixtures using ABS Test (ABS Test를 이용한 아스팔트 혼합물의 수분에 의한 점착특성 평가)

  • Son, Jeong Tan;Yang, Sung Lin;Shin, O-Cheol;Rhee, Suk Keun;Im, Jeong Hyuk
    • International Journal of Highway Engineering
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    • v.19 no.2
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    • pp.87-95
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    • 2017
  • PURPOSES : The objectives of this study are to evaluate moisture sensitivity of various asphalt mixtures and to suggest an alternate method for the dynamic immersion test, which is used to determine the application of anti-stripping agent, by analyzing bond strength. METHODS : The bond strength of various asphalt mixtures such as hot mix asphalt, warm mix asphalt, and polymer-modified asphalt was evaluated by the ABS test. In order to characterize moisture sensitivity at different temperatures of the mixtures, the ABS test was conducted at $-10^{\circ}C$, $5^{\circ}C$, $20^{\circ}C$, $40^{\circ}C$, and $54^{\circ}C$ under both dry and wet conditions. The concept of the bond strength ratio was applied for objective moisture sensitivity analysis. Moreover, the bond strength characteristic was compared to the dynamic immersion test to suggest an alternate method to determine the application of anti-stripping agent. RESULTS AND CONCLUSIONS : Overall, the polymer-modified asphalt demonstrates the highest bond strength characteristic regardless of moisture condition and temperature. The bond strength characteristic displays a highly reliable linear relationship from $5^{\circ}C$ to $40^{\circ}C$, and the relationship could be used to predict bond strength at any intermediate temperature. Based on the analysis of bond strength and retained asphalt ratio, the bond strength value of 1254 kPa could be applied as a criterion for anti-stripping agent.

Shear Bond Strength Between Zirconia and Porcelain (지르코니아와 포세린의 전단결합강도)

  • Kim, Sa-Hak
    • The Journal of Korean Academy of Dental Technology
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    • v.33 no.1
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    • pp.1-6
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    • 2011
  • Purpose: To examine the shear bond strengths of zirconia and veneering ceramic according to their surface processing. Methods: The test samples were divided into three groups: one without zirconia surface processing, one sandblasted, and one sandblasted then 3% etched. Then veneering ceramic was fired on all test samples, and their shear bond strengths were measured. Results: The test samples of the control group (Z1) showed the lowest shear bond strengths of $21.82{\pm}1.02$ MPa. The shear bond strengths of Z2 and Z3 ($28.25{\pm}0.72$ and $26.23{\pm}0.82$ MPa, respectively) were relatively higher than those of the control group. The fracture surface of the control group showed adhesive fractures while the test groups had relatively large numbers of cohesive fractures. Conclusion: The shear bond strength was high in the test groups with surface processing while the fracture surfaces showed compound fractures of adhesive and cohesive fractures.

An Experimental Study on the Bond Split Mechanism of High Strength Concrete (고강도 콘크리트의 부착할렬기구에 관한 실험적 연구)

  • 장일영
    • Journal of the Korea Concrete Institute
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    • v.11 no.4
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    • pp.129-136
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    • 1999
  • For the prediction of concrete-steel bond ability in reinforced concrete, many countries establish specifications for the pullout test. But these methods hardly to consider many parameters such as strength, shape, diameter and location of steel, concrete restrict condition by loading plate, strength of concrete and cover depth etc, and it is difficult to solve concentration and disturbance of stress. The purpose of this study is to propose a New Ring Test method which can be rational quantity evaluations of bond splitting mechanism. For this purpose, pullout test was carried out to assess the effect of several variables on bond splitting properties between reinforcing bar and concrete. Key variables are concrete compressive strength, concrete cover, bar diameter and rib spacing. Failure mode was examined and maximum bond stress-slip relationships were presented to show the effect of above variables. As the result, it appropriately expressed general characteristics of bond splitting mechanism, and it proved capability for standard test method.

Bond Models for GFRP Rebar Embedded in Concrete (GFRP 보강근과 콘크리트 사이의 부착모델에 관한 고찰)

  • You, Young-Jun;Park, Ji-Sun;Park, Young-Hwan;Kim, Hyeong-Yeol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.3
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    • pp.143-151
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    • 2006
  • This paper presents the comparison of the goodness-of-fit test of analytical bond models between concrete and steel or GFRP reinforcements. Bond test specimens were prepared in accordance with the CSA codes and the rebars used in the test were steel and two types of commercial GFRP rebar products. Using the test data, a bond model was proposed, and comparison of goodness-of-fit test for existing bond models and proposed bond model was carried out by the least squares method. The result indicates that the proposed bond model has better goodness-of-fit test than the existing ones.

Residual bond behavior of high strength concrete-filled square steel tube after elevated temperatures

  • Chen, Zongping;Liu, Xiang;Zhou, Wenxiang
    • Steel and Composite Structures
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    • v.27 no.4
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    • pp.509-523
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    • 2018
  • This paper presents experimental results on the residual bond-slip behavior of high strength concrete-filled square steel tube (HSCFST) after elevated temperatures. Three parameters were considered in this test: (a) temperature (i.e., $20^{\circ}C$, $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$); (b) concrete strength (i.e., C60, C70, C80); (c) anchorage length (i.e., 250 mm, 400 mm). A total of 17 HSCFST specimens were designed for push-out test after elevated temperatures. The load-slip curves at the loading end and free end were obtained, in addition, the distribution of steel tube strain and the bond stress along the anchorage length were analyzed. Test results show that the shape of load-slip curves at loading ends and free ends are similar. With the temperature constantly increasing, the bond strength of HSCFST increases first and then decreases; furthermore, the bond strength of HSCFCT proportionally increases with the anchoring length growing. Additionally, the higher the temperature is, the smaller and lower the bond damage develops. The energy dissipation capacity enhances with the concrete strength rasing, while, decreases with the temperature growing. What is more, the strain and stress of steel tubes are exponentially distributed, and decrease from the free end to loading end. According to experimental findings, constitutive formula of the bond slip of HSCFST experienced elevated temperatures is proposed, which fills well with test data.

Bond Strength of Reinforcing Steel to High Strength, High Flow Belite Concrete (고강도, 고유동 Belite 콘크리트의 부착성능)

  • 김상준;조필규;이세웅;최완철
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.653-660
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    • 1998
  • Bond strength of reinforcing bar to high-performance concrete using belite cement is explored using beam end test specimen. The key parameters for the bond test are slump of concrete, top bar effect, and strength of concrete in addition to concrete covers. Specimen failed in the typical brittle bond failure splitting the concrete cover as the wedging action. The test results show that the specimens with belire cement concrete show higher bond strength than those with portland cement concrete. Bond strength of the top bar is less than bond strength of bottom bar, but the top bar factor satisfies the modification factor for top reinforcement. The results also show that the bond strength is function of the square root of concrete compressive strength and cover thickness. The recently developed high-strength and high-slump concrete with belite cement performs well in terms of bond strength to reinforcing steel.

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An experimental study on Bond strength of Reinforcing steel to High-performance Concrete using Belite Cement (Belite 시멘트를 이용한 고성능 콘크리트의 철근 부착성능 실험연구)

  • 조필규;김상준;강지훈;김영식;최완철
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.408-415
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    • 1997
  • Bond strength of reinforcing bar to high-performance concrete using Belite cement is explored using beam end test specimen. The key parameters for the bond test are slump of concrete, top bar effect, and strength of concrete in addition to concrete covers. Specimen failed in the typical brittle bond failure splitting the concrete cover as the wedging action. The test results show that for the group with portland cement I using superplasticizer additional slump does not decrease the bond strength of the top bar is less than bond strength of bottom bar, but the top bar factor satisfy the modification factor for top reinforcement. The result also show that bond strength is function of square root of concrete compressive strength and cover thickness. More detailed evaluation will be conducted from the test specimen with high strength concrete using the belite cement.

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