• 한국농공학회논문집
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• 제50권5호
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• pp.51-60
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• 2008

This study is to relate the bond characteristics of CFRP rebar in high strength concrete incorporated with silica fume(SF) and metakaolin(MK). An direct bond test were performed to evaluate the effect of SF and MK on bond properties of high-strength concrete and CFRP rebar. The high strength concrete mix included four SF and MK mixes with 0%, 5%, 10% and 15%. Results of bond performance experiment in relation to pullout vs slip behavior of FRP rebar and high strength showed better performance of SF than MK. Also, the results showed the improved bond strength as replacement ratio of SF and MK increased. The relative bond strength in which $1.3{\sim}3.2$ of estimated values were obtained.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.445-448
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• 2004

Recently, bridge deck overlay with latex modified concrete is widely applied in domestic. the capacity of bridge deck overlay depends on bond state on the surface. factors that have an effect on bond state are clean condition on the surface, absence of surface microcracking, absence of laitance, overlay curing. In this study, it is researched that characteristic of bond strength according to moisture condition on the surface and the removal method of concrete. As a result, it shows high bond strength in dry condition when w/c is $31\%$ and in moisture condition when w/c is $38\%$ respectively. characteristic of bond strength according to the removal method of concrete shows high bond strength when using water-jets rather than jackhammers.

• Advances in concrete construction
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• 제14권5호
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• pp.331-339
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• 2022

Geopolymer concrete (GPC) is one of the best substitute materials for conventional concrete in construction. The conventional concrete provided by Portland cement has a detrimental influence on the environment during its production. In this study, the bond strength, which is an important structural property, of deformed steel bars with slag-based GPC was measured. In accordance with the ASTM C234 procedure, bond strength was measured on 18 specimens of slag-based GPC with three sizes of steel bars and different embedded lengths. Two groups of GPC specimens with different compressive strengths, which were cured under ambient conditions, were tested. The results indicated that the bar diameter has a great effect on the bond strength, and the bond strength behavior of the slag-based GPC is comparable with that of conventional concrete. The ACI-318 Code for the bond strength of ordinary Portland cement concrete can be used conservatively to determine the bond strength of the GPC reinforced with deformed steel bars.

• 대한치과보철학회지
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• 제34권2호
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• pp.233-245
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• 1996

The purpose of this study was to evaluate the effect of thermocycling on bond strength between metal and resin cement according to thermocycling, and to observe the bond failure modes with optical microscope(X30). For this purpose, Super-Bond C & B and Panavia 21 resin cement were used. Metal specimens were made of Vera-Bond and the surface of specimens were sandblasted with $50{\mu}m$ aluminum oxide. All experimental groups were stored in $37^{\circ}C$ distilled water for 72 hours, followed by thermocycling between $5^{\circ}C$ and $55^{\circ}C$ with 15 second dwell time. 500, 1000, 2000 cycles of thermocycling were executed and the tensile bond strength was measured by Instron Universal Testing Machine(Model 4201) The obtained results were as follows : 1. Super-Bond C & B and Panavia 21 did not show statistically significant difference accor-ding to thermocycling test(P>0.05). 2. Super-Bond C & B specimens exhibited statistically significant higher tensile bond stre-ngth than Panavia 21 for all experimental groups(P<0.05). 3. Super-Bond C & B exhibited mixed mode failure with partial adhesive and partial cohe-sive failure, and most of Panavia 21 exhibited cohesive failure and some mixed mode failure.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.446-453
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• 2015

PURPOSE. To compare the push-out bond strength of feldspar and zirconia-based ceramic inlays bonded to dentin with different resin cements following simulated aging. MATERIALS AND METHODS. Occlusal cavities in 80 extracted molars were restored in 2 groups (n=40) with CAD/CAM feldspar (Vitablocs Trilux forte) (FP) and zirconia-based (Ceramill Zi) (ZR) ceramic inlays. The fabricated inlays were luted in 2 subgroups (n=20) with either etch-and-bond (RelyX Ultimate Clicker) (EB) or self-adhesive (RelyX Unicem Aplicap) (SA) resin cement. Ten inlays in each subgroup were subjected to 3,500 thermal cycles and 24,000 loading cycles, while the other 10 served as control. Horizontal 3 mm thick specimens were cut out of the restored teeth for push out bond strength testing. Bond strength data were statistically analyzed using 1-way ANOVA and Tukey's comparisons at ${\alpha}=.05$. The mode of ceramic-cement-dentin bond failure for each specimen was also assessed. RESULTS. No statistically significant differences were noticed between FP and ZR bond strength to dentin in all subgroups (ANOVA, P=.05113). No differences were noticed between EB and SA (Tukey's, P>.05) bonded to either type of ceramics. Both adhesive and mixed modes of bond failure were dominant for non-aged inlays. Simulated aging had no significant effect on bond strength values (Tukey's, P>.05) of all ceramic-cement combinations although the adhesive mode of bond failure became more common (60-80%) in aged inlays. CONCLUSION. The suggested cement-ceramic combinations offer comparable bonding performance to dentin substrate either before or after simulated aging that seems to have no adverse effect on the achieved bond.

• Restorative Dentistry and Endodontics
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• 제21권2호
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• pp.569-584
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• 1996

The purpose of this study was to elucidate the effect of benzalkonium chloride on tensile bond strength of BPDM/HEMA dentin bonding. One hundred sixty dentin specimens from freshly extracted bovine mandibular incisors were used, and 0, 0.02, 0.1 or 0.5% benzalkonium chloride solution was applied to the dentin specimen with/after phosphoric acid. 32% phosphoric acid was used when the specimens were bonded with One-Step$^{TM}$, a BPDM/HEMA system and 10% was used when bonded with All-Bond$^{(R)}$ 2, a NTG-GMA/BPDM system. Aelitefil$^{TM}$ composite resin was bonded to the pretreated dentin specimen with the use of All-Bond$^{(R)}$ 2 or One-Step$^{TM}$ dentin bonding agent. After the bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, tensile bond strength was measured. The fractured dentin specimens were examined under the scanning electron microscope. The results were as follows : Benzalkonium chloride application after acid-treatment resulted in decrease of dentin bond strength of One-Step$^{TM}$, a BPDM/HEMA system (p>0.05). Benzalkonium chloride application did not exert any influence on dentin bond strength of All-Bond$^{(R)}$ 2, a NTG-GMA/BPDM system (p>0.05). There was no relationship between the concentration or application method of benzalkonium chloride and the dentin bond strength of One-Step$^{TM}$ or All-Bon$^{(R)}$ 2 (p<0.05). On SEM examination of the fractured dentin-resin interface, while mixed failure was prominent in dentin bonding with One-Step$^{TM}$, adhesive and mixed failures were seen together in dentin bonding with All-Bond$^{(R)}$ 2 regardless of the concentration and application method of benzalkonium chloride.

• Restorative Dentistry and Endodontics
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• 제16권2호
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• pp.126-142
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• 1991

The purpose of this study was to evaluate the effect of various dentin surface treatments on shear bond strength, microhardness and fracture mode before and after thermocycling. Recently extracted 75 human molars were used. The teeth were sagittal sectioned faciolingually to obtain 150 specimens. They were randomly divided into six groups. Mesial and distal dentinal surfaces of specimens were exposed by grinding and treated respectively with GC-DENTIN CONDITIONER. 10-3 solution of 4-Meta, Cleansar and Primer of GLUMA, Scotchprep of Scotchbond 2, DENTIN CONDITIONER and PRIMER A, B of ALL BOND according to the manufacturers directions. Specimens of one group were not treated. Adhesive agent of Scotchbond 2, were applied and cured on the treated dentin surfaces. After P-50 were cured on them, specimens were stored in 31c water for 24 hours before shear bond strength measurement Shear bond strength was measured in 10 specimens of each group. 10 specimens of each group were thermocycled in $20^{\circ}C$, $60^{\circ}C$,$20^{\circ}C$, $4^{\circ}C$, $20^{\circ}C$ water in order, for 30 seconds respectively, 100 times a day for 7 days. After thermocycling shear bond strength was measured. Microhardness was checked on treated dentin surface and fractured dentin surface in 10 specimens respectievly. Francture modes were observed with SEM The following results were obtained. 1. Before thermocycling. shear bond strengths in the specimens treated with DENTIN CONDITIONER and PRIMER A, B of ALL BOND were significantly higher than those in other specimens(P<0.01). 2. After thermocycling. shear bond strengths in the specimens treated with Cleanser and Primer of GLUMA, Scotchprep of Scotchbond 2 and DENTIN CONDITIONER and PRIMER A, B of AIL BOND were significantly higher than those in specimens not: treated, treated with GC-DENTIN CONDITIONER and 10-3 solution of 4-Meta(P<0.01). Shear bond strengths in the specimens treated with GC-DENTIN CONDITIONER and PRIMER A, B of ALL BOND were significantly higher than those in other specimens except those treated with Scotchprep of Srotchbond 2(P<0.01). 3. Shear bond strengths after thermocycling were reduced in the specimens not treated, treated with GC-DENTIN CONDITIONER and 10-3 solution of 4-Meta and were increased in the specimens treated with Cleanser and Primer of GLUMA, Scotchprep of Scotchbond 2, without significance, compared with those before thermocycling. In the specimens treated with DENTIN CONDITIONER and PRIMER A, B of ALL BOND, shear bond strengths after thermocycling were significantly increased, compared with those before thermocycling(P<0.01). 4. Microhardnesses in the fractured surfaces after shear bond strength measurement were significantly increased in the specimens treated with 10-3 solution of 4-Meta and significantly decreased in the specimens treated with DENTIN CONDITIONER and PRIMER A, B of ALL BOND, compared with those in the treated dentin surfaces(P<0.01). 5. In the specimens treated with Cleanser and Primer of GLUMA, Scotchprep of Scotchbond 2 and DENTIN CONDITIONER and PRIMER A, B of ALL BOND, cohesive fracture modes were observed more than adhesive fracture modes.

• International Journal of Concrete Structures and Materials
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• 제18권1E호
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• pp.29-34
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• 2006

Elastic modulus, tensile and bond capacities are important factors for developing an effective reinforcing action of a flexural member as a reinforcing material for concrete structures. Reinforcement must have enough bond capacity to prevent the relative slip between concrete and reinforcement. This paper presents an experimental study to clarify the bond capacity of prestressed carbon fiber reinforced polymer(CFRP) rod manufactured by an automatic assembly robot. The bond characteristics of CFRP rods with different pitch of helical wrapping were analyzed experimentally. As the result, all types of CFRP rods show a high initial stiffness and good ductility. The mechanical properties of helical wrapping of the CFRP rods have an important effect on the bond of these rods to concrete after the bond stress reached the yield point. The stress-slip relationship analyzed from the pull-out test of embedded cables within concrete was linear up to maximum bond capacity. The deformation within the range of maximum force seems very low and was reached after approximately 1 mm. The average bond capacity of CF20, CF30 and CF40 was about 12.06 MPa, 12.68 MPa and 12.30 MPa, respectively. It was found that helical wrapping was sufficient to yield bond strengths comparable to that of steel bars.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.1135-1142
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• 2021

This study aims to examine the factors that determine bond yields in infrastructure companies listed on the Indonesia Stock Exchange. The research sample used 31 bonds issued by the company during the 2015-2019 period. The data analysis method to estimate the determinant of bond yield uses multiple regression models. The results prove that the increase in the coupon rate causes bond yields to increase, while the inflation rate has the opposite effect of decreasing bond yield. Interest rate, exchange rate, duration, and bond rating variables cannot affect the bond yield. The results of this study imply that investors will be interested in investing in bonds with better yields if the company has to set a higher coupon rate, especially in economic conditions that experience low inflation rates. Interest rates and exchange rates as macroeconomic variables have not been considered by investors in purchasing bonds. Bond characteristic factors, namely, the duration and rating of the bonds, are considered less important factors in bond investment decisions because they are more oriented towards getting higher yields. Therefore, further research needs to be explored further related to the behavior of Indonesian bond investors who may have different characters from investors in other countries.

• 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.