• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.361-366
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• 2018

PURPOSE. The aim of this study was to evaluate the effects of relining materials on the flexural strength of relined thermoplastic denture base resins (TDBRs). MATERIALS AND METHODS. For shear bond strength testing, 120 specimens were fabricated using four TDBRs (EstheShot-Bright, Acrytone, Valplast, Weldenz) that were bonded with three autopolymerizing denture relining resins (ADRRs: Vertex Self-Curing, Tokuyama Rebase, Ufi Gel Hard) with a bond area of 6.0 mm in diameter and were assigned to each group (n=10). For flexural strength testing, 120 specimens measuring $64.0{\times}10.0{\times}3.3mm$ (ISO-1567:1999) were fabricated using four TDBRs and three ADRRs and were assigned to each group (n=10). The thickness of the specimens measured 2.0 mm of TDBR and 1.3 mm of ADRR. Forty specimens using four TDBRs and 30 specimens using ADRRs served as the control. All specimens were tested on a universal testing machine. For statistical analysis, Analysis of variance (ANOVA) with Tukey's test as post hoc and Spearman's correlation coefficient analysis (P=.05) were performed. RESULTS. Acry-Tone showed the highest shear bond strength, while Weldenz demonstrated the lowest bond strength between TDBR and ADRRs compared to other groups. EstheShot-Bright exhibited the highest flexural strength, while Weldenz showed the lowest flexural strength. Relined EstheShot-Bright demonstrated the highest flexural strength and relined Weldenz exhibited the lowest flexural strength (P<.05). Flexural strength of TDBRs (P=.001) and shear bond strength (P=.013) exhibited a positive correlation with the flexural strength of relined TDBRs. CONCLUSION. The flexural strength of relined TDBRs was affected by the flexural strength of the original denture base resins and bond strength between denture base resins and relining materials.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.401-406
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• 2008

This study can be used to produce structurally efficient recycled PET fiber from used waste PET bottles and evaluated the bond performance of the three type of recycled PET fiber and cement matrix. Also, the flexural tests were performed on concrete reinforced using the three type of recycled PET fibers. The test results showed that the recycled PET fiber was significantly increased bond strength. The flexural test results are demonstrated that recycled PET fibers improved the flexural toughness of concrete. Based on the bond and flexural test results, the bond and flexural performance of embossed type recycled PET fibers were significantly better than those of the other shape fibers.

• KCI Concrete Journal
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• v.14 no.1
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• pp.1-7
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• 2002

This paper reports the experimental and analytical investigations for evaluating the flexural strength of a RC slab strengthened with carbon fiber sheet (CFS). The evaluation of the ultimate flexural strength of a slab is tried under the assumption that the failure occurs when the shear stress mobilized at the interface between the concrete bottom and the glued CFS reaches its bond strength. The shear stress is evaluated theoretically and the bond strength is obtained by a laboratory test. The ultimate flexural strength is obtained by flexural static test of the slab specimen, which corresponds to the part of a real slab. From the results, the new approach based on the bond strength between concrete and CFS looks feasible to evaluate the flexural strength of the CFS and RC composite slab.

• Steel and Composite Structures
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• v.6 no.5
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• pp.387-400
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• 2006

This paper discusses the composite mechanism and its effect upon the behavior of a steel reinforced concrete (SRC) member subjected to a flexural load. The relationship between member strength and deformation is established using the bond strength between the steel and reinforced concrete. An analytical model is proposed and used to incorporate the sectional strains and bond strength at the elastic and inelastic stages for moment-curvature relationship derivation. The results from the flexural load tests are used to validate the accuracy of the proposed model. Comparisons between the experimental information and the analytical results demonstrate close moment-curvature relevance, which justifies the applicability of the proposed method.

• Computers and Concrete
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• v.6 no.3
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• pp.235-252
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• 2009

Due to the reduction of bond strength resulting from the high corrosion level of reinforcing bars, influence of this reduction on flexural capacity of reinforced concrete (RC) beam should be considered. An extreme case is considered, where bond strength is complete lost and/or the tensile steel are exposed due to heavy corrosion over a fraction of the beam length. A compatibility condition of deformations of the RC beam with partially unbonded length is proposed. Flexural capacity of this kind of RC beam is predicted by combining the proposed compatibility condition of deformations with equilibrium condition of forces. Comparison between the model's predictions with the experimental results published in the literature shows the practicability of the proposed model. Finally, influence of some parameters on the flexural capacity of RC beam with partially unbonded length is discussed. It is concluded that the flexural capacity of the beam may not be influenced by the completely loss of bond of the whole beam span as long as the tensile steel can yield; whether or not the reduction of the flexural capacity of the beam resulting from the loss of bond over certain length may occur depends on the detailed parameters of the given beam.

• Journal of Technologic Dentistry
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• v.37 no.4
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• pp.219-227
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• 2015

Purpose: The purpose of this study was to evaluate the effect of the chemical surface treatment on the flexural bond strength of heat curing denture base resin and reliners. Methods: Denture base resin surface was treated with MMA 95% and TEGDMA 5%, MMA 95% and silane coupling agent 5%, heat curing resin monomer. After denture reliners were injected, flexural bond strength was measured. Results: The repair resin of Vertex SC was higher than Lang, hard reliner of Kooliner was higher than Rebase. Soft reliner of Dura base and Coe-soft showed differently according to the surface treatment. The all chemical treatment groups on Vertex SC were significantly higher than control(p<0.05). In Lang group, 5% MPS treated group showed significantly higher flexural bond strength than others(p<0.05). In Kooliner group, all chemical treatment groups showed significantly higher than control(p<0.05). In Rebase group, the 5% MPS and the monomer denture base resin treated groups showed significantly higher than others(p<0.05). In Dura base group, 5% MPS treated group showed significantly higher flexural bond strength than others(p<0.05). In Coe-soft group, all treated groups were significantly higher than control group(p<0.05). Conclusion: TEGDMA, MPS, and the monomer of heat-cured denture base resin were effective to improve the bond strengths between denture base and denture relining materials. Especially, 5% MPS expected to strengthen effectively the bonding property of denture base and denture reliners within the results of this study.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.997-1002
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• 2001

Tensile strength of CFRP (Carbon Fiber Reinforced Polymer) is approximately 10 times higher than that steel reinforcement, but the design strength of CFRP is normally reduced by the bond failure between RC and CFRP. Many researches have been carried out, concerned with bond behavior between RC and CFRP to prevent the unpredicted bond failure of RC beam strengthened by CFRP, but the national design code for design bond strength of CFRP hasn't been constructed. In this study, 3 beams specimen strengthened by CFRP under the variable of bonded length were tested to derive the design bond strength of CFRP to the RC flexural members. Also 2 beams specimen strengthened by CFRP were tested to inspect the construction environment effects such as mixing error of epoxy resin and the amount of primer epoxy resin. From the test results, It is concluded that the maximum design bond strength of CFRP to RC flexural member is considered to be $\tau_{a}$=8kgf/$cm^{2}$.

• Journal of Technologic Dentistry
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• v.40 no.4
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• pp.225-230
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• 2018

Purpose: The purpose of this study was to evaluate the effect of denture cleansers on the flexural bond strength of heat curing denture base resin and reliners. Methods: The denture base resin was bonded to the reliners(vertex self curing, kooliner, rebase II) to make the specimen. The specimens were immersed in denture cleansers(Polident, Cleadent) and evaluated after 1week, 3week, 5weeks. After denture reliners were injected, flexural bond strength was measured. Results: The bond strength of denture base resin and vertex self curing resin as reliner was significantly decreased at 5 weeks in cleadent and polident(p<0.05). The bond strength of kooliner and rebase II was significantly decreased at 5 weeks in denture cleaners(p<0.05). Kooliner was significantly decreased at 3 and 5 weeks in polident and rebase II was significantly decreased at 3 and 5 weeks in all denture cleansers(p<0.05). Conclusion : The flexural strength between the denture base resin and the reliners decreased significantly as the treatment time increased.

• Journal of Technologic Dentistry
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• v.33 no.3
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• pp.193-202
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• 2011

Purpose: The aim of this study was to evaluate the effect of pre-treatment of core and hydrothermal treatment on the bond strength and flexural strength of ceramic veneered zirconia. Methods: 3Y-TZP specimens(KaVo Zr, $25mm{\times}3mm{\times}1mm$)were prepared by five pre-treatment methods and divided into seven groups including control two groups, subsequently the specimens veneered with the E-MAX ceram according to manufacturer's information(total specimen thickness 1.5mm). Two groups from ceramic-zirconia specimens(n=105, n=15 per group)were assigned into two experimental fatigue conditions, namely storage in an autoclave at $134^{\circ}C$ for 5h, thermo-cycling(3,000cycles, between 5 and $55^{\circ}C$, dwell time 45s, transfer time 2s). A flexural strength test was performed in a universal testing machine(crosshead speed: 0.5mm/min). Data were statistically analyzed using one-way ANOVA and Tukey's test(${\alpha}$=0.05). Results: The ceramic-zirconia bond strength value for liner application group(LLW, $27.3{\pm}3.8$) were significantly lower than those of the pre-treatment groups($30.72{\pm}5.3$). The ceramic-zirconia bond strength and zirconia flexural strength was not affected by thermo-cycling(p>0.05), whereas it was affected by storage in an autoclave at $134^{\circ}C$ for 5h(p<0.05). Conclusion: The results indicated that the ceramic-zirconia bond strength and zirconia flexural strength was affected by low temperature degradation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.3 s.55
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• pp.155-163
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• 2009

The purpose of this paper is to investigate the bond strength between old and new concrete as well as flexural tensile strength of concrete. To achieve this purpose, a comprehensive experimental program has been set up and strength tests using a series of specimens have been carried out. The present study represents that the flexural bond strength between old and new concrete is much smaller than that of flexural tensile strength. The ratio of bond strength to flexural tensile strength ranged through 15~27%. It is seen that concrete-to-concrete bond strength has been affected by curing condition. Also, test results of tensile strength show that recommendation by ACI 363 committee is estimated to be more realistic than another recommendations for predicting tensile strength of concrete.