• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.162-163
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• 2019

The purpose of this study is to evaluate the adhesion in flexure of SBR-modified mortar adding Fly Ash(FA). From the test results, the adhesion in flexure is seriously affected by polymer-binder ratios and adding content of FA. The maximum adhesion in flexure of SBR- modified mortar is about 1.46 times, the plain cement mortar. It is apparent that the adhesion in flexure of SBR-modified mortars by polymer-binder ratios is much more improved than that by adding contents of AF.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.47-57
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• 2019

The purpose of this study is to evaluate the improvement effect of adhesion in tension and flexure of polymer cement mortars that have widely used as a repair-reinforcement material in construction field according to adding of polymer dispersions depending on different three types test methods. From the test results, the adhesion performance is improved with a raise in polymer-cement ratio irrespective of the type of polymer. The maximums of A type adhesion in tension, B type adhesion in tension and adhesion in flexure show 1.90 times, 2.17 times and 1.83 times, respectively that of plain cement mortar. The relative strength ratios, B type adhesion in tension and adhesion in flexure of polymer cement mortars to tensile and flexural strengths of plain mortar respectively are in ranges of 50.1% to 101.7% and 73.8% to 132.9% compared to 46.9% of plain mortar. It is apparent that polymer cement mortars with EVA and polymer cement ratios of 10% to 15% are recommended considering its adhesion performance and cost as a repair-reinforcement material in construction field.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.485-494
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• 2019

This study is to evaluate the effect of admixtures such as blast-furnace slag and fly ash on adhesion in flexure and tension of polymer cement mortar(PCM) using SAE emulsion. The test specimens are prepared with five polymer-cement ratios and five admixture contents, and tested for flexural strength, adhesion in flexure, tensile strength and adhesion in tension. Based on the test results, no improvement of flexural strength and adhesion in flexure caused by admixtures in PCM can be indicated, but the tensile strength and adhesion in tension is improved due to mixing of the admixtures. In particular, the maximum of adhesion in tension of PCM with P/C 20% and BF content of 10% is 3.35MPa which is about 2.36 times higher than that of ordinary cement mortar, and 1.32 times that of PCM that does not contain any admixture. The average ratio of adhesion in tension to tensile strength of PCM was 48.7%. It is apparent that admixture contents of 5% or 10% could be proposed for improvement of tensile strength and adhesion in tension of PCM.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.301-304
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• 2006

The purpose of this study is to evaluate bonding properties of PMMA mortars using EPS with silane coupling agent. PMMA mortars are prepared with various silane coupling agent, and tested for flexural strength test, adhesion test in flexure and tensile strength in underwater and air. It is estimated that the application of silane coupling agent to PMMA mortar is more effective in underwater than air.

• Journal of Adhesion and Interface
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• v.4 no.2
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• pp.1-9
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• 2003

Epoxy-amine liquid prepolymers are extensively applied onto metallic substrates and cured to obtain painted materials or bonded joint structures. Overall performances of such systems depend on the created interphase between the organic layer and the substrate. When epoxy-amine liquid mixtures are applied onto more or less hydrated metallic oxide layer, concomitant amine chemical sorption and hydroxide dissolution appear lending to the chelate formation. As soon as the chelate concentration is higher than the solubility product, these species crystallize as sharp needles. Moreover, intrinsic and thermal residual stresses are developed within painted or bonded systems. When residual stresses are higher than the organic layer/substrate adhesion, buckling, blistering, debonding may occur leading to a catastrophic drop of system performances. Practical adhesion can be evaluated with either ultimate parameters (Fmax or Dmax) or the critical strain energy release rate, using the three point flexure test (ISO 14679-1997). We observe that, for the same system, the ultimate load decreases while residual stresses increase when the liquid/solid time increases. Ultimate loads and residual stresses depend on the metallic surface treatment. For these systems, the critical strain energy release rate which takes into account the residual stress profile and the Young's modulus gradient remains quite constant whatever the metallic surface treatment was. These variations will be discussed and correlate to the formation mechanisms of the interphase.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.601-610
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• 2007

Statement of problem: The adhesion between titanium and ceramic is less optimal than conventional metal-ceramic bonding, due to reaction layer form on cast titanium surface during porcelain firing. Purpose: This study characterized the effect of titanium-ceramic adhesion after gold and TiN coating on cast and wrought titanium substrates. Material and method: Six groups of ASTM grade II commercially pure titanium and cast titanium specimens$(13mm{\times}13mm{\times}1mm)$ were prepared(n=8). The conventional Au-Pd-In alloy served as the control. All specimens were sandblasted with $110{\mu}m\;Al_2O_3$ particles and ultrasonically cleaned for 5min in deionized water and dried in air before porcelain firing. An ultra-low-fusing dental porcelain (Vita Titankeramik) was fused on titanium surfaces. Porcelain was debonded by a biaxial flexure test at a cross head speed of 0.25mm/min. The excellent titanium-ceramic adherence was exhibited by the presence of a dentin porcelain layer on the specimen surface after the biaxial flexure test. Area fraction of adherent porcelain (AFAP) was determined by SEM/EDS. Numerical results were statistically analyzed by one-way ANOVA and Student-Newman-Keuls test at ${\alpha}=0.05$. Results: The AFAP value of cast titanium was greatest in the group 2 with TiN coating, followed by group 1 with Au coating and the group 3 with $Al_2O_3$ sandblasting. Significant statistical difference was found between the group 1, 2 and the group 3 (p<.05). The AFAP value of wrought titanium was greatest in the group 5 with TiN coating, followed by the group 4 with Au coating and the group 6 with $Al_2O_3$ sandblasting. Conclusion: No significant difference was observed among the three groups (p>.05). The AFAP values of the cast titanium and the wrought titanium were similar. However the group treated with $Al_2O_3$ sandblasting showed significantly lower value (p<.05).

• Journal of Technologic Dentistry
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• v.29 no.2
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• pp.213-223
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• 2007

The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. The adhesion between metal substructure and dental porcelain is related to the diffusion of oxygen to the reaction layer formed on cast-metal surface during firing. The purposed of this investigation was to study the effects of gold based bonding agent on Ni-Cr alloy-ceramic adhesion between porcelain matrix, gold based bonding agent and metal substructure interface. gold based bonding agent have been applied as an intermediate layer between a metal substructure and a ceramic coating. gold based bonding agent(Aurofilm NP, Metalor, Swiss) was applied on Ni-Cr alloy surface by four method. Surfaces only air abraded with 110${\beta}\neq$ Al2O3 particles were used as control. metal ceramic adhesion was evaluated by a biaxial flexure test(N=5) and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that the layering sequence of gold based bonding agent is very important and can improve porcelain adherence to PFM.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.149-156
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• 2003

The development and maintenance of a sound bond are essential requirements of concrete repair and replacement. The bond property of a overlay to its substrate concrete during the lifetime is one of the most important performance requirements which should be quantified. A standard or a verified bond strength measurement method is required at field for screening, selecting materials and quality control for overlay or repair materials, but no test method has been adopted as a standard. In this study, a concrete pull off bond strength measurement method for field application is proposed and evaluated. This study compares the splitting tensile test, slant shear test, nipple pipe direct tensile test, flexural adhesion test, briquette tensile test, jumbo nail pull-out test and core pull-off test with their test procedures. From these comparison and investigation, core pull-off test is selected as a main topic of this study because of it's suitability for in situ testing, simplicities in field application and clearness at interface boundary condition. Thus, the proposed core pull off test is evaluated to be the most appropriate method for field application in a simple manner. The fracture surface and fracture mode could be easily determined by visual observation of failure surface of the field specimen. The core pull off test was found to be sensitive to surface condition and latex contents at latex modified concrete.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.405-412
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• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.176-181
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• 2018

Concrete structures are degraded physically and chemically due to various reasons after construction. Because the deterioration of concrete structure reduces the service life, reasonable repair and maintenance techniques are needed. Recently, in order to efficiently repair concrete structures, many researches on hybrid repair materials having improved adhesion performance have been carried out actively. In this study, we developed a hybrid repair material containing rapid hardening cement, PVA powder, nylon fiber, and latex to improve adhesion and water-tightness of existing concrete. The compressive strength, drying shrinkage and the adhesion strength test were carried out to evaluate the performance of the repair material. In addition, the flexure bond performance was evaluated before and after repair. From the results, the bending strength was 110% ~ 150% in all specimens except for the specimen containing only the rapid hardening cement, and all the specimens behaved with the existing concrete in the crack pattern generated by the bending strength.