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Zhiqiang Dong - One of the best experts on this subject based on the ideXlab platform.

  • Long-Term Bond Durability of Fiber-Reinforced Polymer Bars Embedded in Seawater Sea-Sand Concrete under Ocean Environments
    Journal of Composites for Construction, 2018
    Co-Authors: Zhiqiang Dong, Xiao Ling Zhao, Jin-long Lian
    Abstract:

    AbstractThis paper presents an experimental study on the Bond Durability of basalt fiber–reinforced polymer (BFRP) bars, steel–fiber reinforced polymer (FRP) composite bars (SFCB), and steel bars e...

  • Bond Durability of steel-FRP composite bars embedded in seawater sea-sand concrete under constant bending and shearing stress
    Construction and Building Materials, 2018
    Co-Authors: Zhiqiang Dong, Xiao Ling Zhao, Hong Zhu, Jin-long Lian
    Abstract:

    Abstract The combination of the new steel-FRP composite bar (SFCB) and natural seawater and sea-sand concrete (SWSSC) has good prospects to be applied in development along the ocean coast and offshore islands. However, at present, there is still a lack of clear understanding on the Durability of this new combination under actual marine service conditions. Therefore, in this paper, the interfacial Bond Durability, which is critical to the overall Durability of SFCB reinforced SWSSC structures, was evaluated by accelerated aging tests. A new type of eccentric pullout test was designed to take into account the bending and shearing stress states of the concrete. The experimental results showed that the Bond strength of SFCBs decreased by 5% after 9 months of aging in a 40 °C seawater wet-dry cycling environment and decreased by 26.2% after 9 months of aging in a 50 °C seawater immersion environment. Due to the surface degradation of the basalt fiber reinforced polymer (BFRP) after exposure, the sheared failure layer gradually transferred from the interface to the inner layer. Based on Fib Bulletin 40, the predicted Bond strength retentions of SFCBs with SWSSC were 84% to 96% after 50 years of service.

  • Bond Durability of BFRP bars embedded in concrete under seawater conditions and the long-term Bond strength prediction
    Materials and Design, 2016
    Co-Authors: Zhiqiang Dong, Bo Xu, Gang Wu, Xin Wang, Luc Taerwe
    Abstract:

    This paper presents a Bond Durability test for the basalt fiber-reinforced polymer (BFRP) bar to concrete immersed in seawater. Glass fiber-reinforced polymer (GFRP) bars, carbon fiber-reinforced polymer (CFRP) bars and steel bars are tested for comparison. Test parameters include the fiber type, the resin type, the temperature and the surface treatment. 114 cube specimens are constructed and tested in direct pullout conditions, and 99 of them are immersed in seawater for different durations and at different temperatures. Scanning electron microscope is used for microstructural observation. Moreover, a long-term Bond strength prediction is conducted on the BFRP bar to concrete. Test results show that the maximum Bond strength of the basalt-vinyl ester (BV) bar and the glass-vinyl ester (GV) bar to concrete experiences degradation, while the value of the basalt-epoxy (BE) bar to concrete remains essentially unchanged. The value of the carbon-epoxy (CE) bar to concrete shows increasing trend. Sand-coating the ribbed BFRP bar reduces the short-term Bond strength but improves the long-term Bond Durability. The prediction results indicate that the Bond strength retention of the BV bar in a chloride environment would be above 93%, 78% and 47% after 50. years' service in dry, moist and moisture saturated environment, respectively.

  • Experimental study on the Bond Durability between steel-FRP composite bars (SFCBs) and sea sand concrete in ocean environment
    Construction and Building Materials, 2016
    Co-Authors: Zhiqiang Dong
    Abstract:

    Abstract Bond Durability tests on steel-fiber reinforced polymer (FRP) composite bars (SFCBs) with sea sand concrete and river sand concrete in simulated ocean environments are conducted in this paper, and steel bars are also used for comparison. Two types of environments, seawater immersion and seawater wet–dry cycling, are adopted. Sixty-six pullout specimens are prepared, and the variations of Bond performance after 30, 60 and 90 days of aging are tested and comparatively analyzed. The test results showed that, with respect to the Bond–slip curves, wave-shaped descending branches were observed for SFCBs; the Bond strength between SFCBs and sea sand concrete in a wet–dry cycling environment at all ages were improved. However, with regard to the steel bars in the same condition, the surfaces were rusted, and the Bond strengths showed a decreasing trend. Immersion in 40 °C seawater reduced the Bond performance of SFCBs with concrete, whereas the rust process of steel bars slowed down due to the lack of fresh oxygen.

Jin-long Lian - One of the best experts on this subject based on the ideXlab platform.

Silmara Aparecida Milori Corona - One of the best experts on this subject based on the ideXlab platform.

  • Bond Durability in erbium:yttrium–aluminum–garnet laser-irradiated enamel
    Lasers in Medical Science, 2010
    Co-Authors: F. L. B. Amaral, A. E. Souza-gabriel, Regina Guenka Palma-dibb, Michelle Alexandra Chinelatti, Vivian Colucci, Silmara Aparecida Milori Corona
    Abstract:

    This study sought to evaluate the influence of thermocycling and water storage on the microtensile Bond strength of composite resin Bonded to erbium:yttrium–aluminum–garnet (Er:YAG)-irradiated and bur-prepared enamel. Eighty bovine incisors were selected and sectioned. Specimens were ground to produce a flat enamel surface. Samples were randomly assigned according to cavity preparation device: (I) Er:YAG laser and (II) high-speed turbine, and were subsequently restored with composite resin. They were subdivided according to the duration of water storage (WS)/number of thermocycles (TCs): 24 h WS/no TCs; 7 days WS/500 TCs; 1 month WS/2,000 TCs; 6 months WS/12,000 TCs. The teeth were sectioned into 1.0 mm^2-thick slabs and subjected to tensile stress in a universal testing machine. Data were submitted to two-way analysis of variance (ANOVA) and Tukey’s test at a 0.05 significance level. The different periods of water storage and thermocycling did not influence the microtensile Bond strength (µTBS) values in the Er:YAG laser-prepared groups. In bur-prepared enamel, the group submitted to 12,000 TCs/6 months’ WS (IID) showed a significant decrease in Bond strength values when compared to the group stored in water for 24 h and not submitted to thermocycling (IIA), but values were statistically similar to those obtained in all Er:YAG laser groups and in the bur- prepared groups degraded with 500 TCs/1 week WS (IIB) or 2,000 TCs/1 month WS (IIC). It may be concluded that adhesion of an etch-and-rinse adhesive to Er:YAG laser-irradiated enamel was not affected by the methods used to simulate degradation of the adhesive interface and was similar to adhesion in the bur-prepared groups in all periods of water storage and thermocycling.

  • Bond Durability in erbium:yttrium-aluminum-garnet laser-irradiated enamel
    Lasers in Medical Science, 2010
    Co-Authors: F. L. B. Amaral, A. E. Souza-gabriel, Regina Guenka Palma-dibb, Michelle Alexandra Chinelatti, Vivian Colucci, Silmara Aparecida Milori Corona
    Abstract:

    This study sought to evaluate the influence of thermocycling and water storage on the microtensile Bond strength of composite resin Bonded to erbium:yttrium-aluminum-garnet (Er:YAG)-irradiated and bur-prepared enamel. Eighty bovine incisors were selected and sectioned. Specimens were ground to produce a flat enamel surface. Samples were randomly assigned according to cavity preparation device: (I) Er:YAG laser and (II) high-speed turbine, and were subsequently restored with composite resin. They were subdivided according to the duration of water storage (WS)/number of thermocycles (TCs): 24 h WS/no TCs; 7 days WS/500 TCs; 1 month WS/2,000 TCs; 6 months WS/12,000 TCs. The teeth were sectioned into 1.0 mm(2)-thick slabs and subjected to tensile stress in a universal testing machine. Data were submitted to two-way analysis of variance (ANOVA) and Tukey's test at a 0.05 significance level. The different periods of water storage and thermocycling did not influence the microtensile Bond strength (microTBS) values in the Er:YAG laser-prepared groups. In bur-prepared enamel, the group submitted to 12,000 TCs/6 months' WS (IID) showed a significant decrease in Bond strength values when compared to the group stored in water for 24 h and not submitted to thermocycling (IIA), but values were statistically similar to those obtained in all Er:YAG laser groups and in the bur- prepared groups degraded with 500 TCs/1 week WS (IIB) or 2,000 TCs/1 month WS (IIC). It may be concluded that adhesion of an etch-and-rinse adhesive to Er:YAG laser-irradiated enamel was not affected by the methods used to simulate degradation of the adhesive interface and was similar to adhesion in the bur-prepared groups in all periods of water storage and thermocycling.

Junji Tagami - One of the best experts on this subject based on the ideXlab platform.

  • long term tensile Bond Durability of two different 4 meta containing resin cements to dentin
    Dental Materials, 2002
    Co-Authors: Yuichi Kitasako, Toru Nikaido, Michael F. Burrow, Junji Tagami
    Abstract:

    Objectives: This study was conducted to evaluate the tensile Bond Durability of two different types of 4-META containing resin cements over a period of 3 years. Methods: Ten bovine dentin specimens were tested for tensile Bond strengths with each of the following materials: Super Bond C&B: unfilled methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) resin cement, MASA Bond (experimental material): filled dimethacrylate resin cement at 1 day, 6 months, 1 and 3 years. The mean Bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P<0.05). The mode of failure was classified by SEM observation. Results for the mode of fracture were analyzed using the Mann–Whitney U test. Results: Although there was no statistical difference in mean Bond strength between Super Bond C&B and MASA Bond (P>0.05) during the experimental periods, the 1-day Bond strengths were significantly greater than those at the other experimental periods except for 6 months (P<0.05). Regarding the fracture modes, at 6 months and 1 year, statistical differences were observed between Super Bond C&B and MASA Bond (P<0.05). Significance: The Bond strengths of both resin cements to dentin significantly decreased after 6 months, and the long-term failure patterns of the 4-META/TBB resin cements showed a marked change.

  • Long-term tensile Bond Durability of two different 4-META containing resin cements to dentin.
    Dental materials : official publication of the Academy of Dental Materials, 2002
    Co-Authors: Yuichi Kitasako, Toru Nikaido, Michael F. Burrow, Junji Tagami
    Abstract:

    Objectives: This study was conducted to evaluate the tensile Bond Durability of two different types of 4-META containing resin cements over a period of 3 years. Methods: Ten bovine dentin specimens were tested for tensile Bond strengths with each of the following materials: Super Bond C&B: unfilled methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) resin cement, MASA Bond (experimental material): filled dimethacrylate resin cement at 1 day, 6 months, 1 and 3 years. The mean Bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P0.05) during the experimental periods, the 1-day Bond strengths were significantly greater than those at the other experimental periods except for 6 months (P

  • the influence of storage solution on dentin Bond Durability of resin cement
    Dental Materials, 2000
    Co-Authors: Yuichi Kitasako, Michael Francis Burrow, Toru Nikaido, Junji Tagami
    Abstract:

    Abstract Objectives: This study was conducted to determine the influence of storage solution on the Bond Durability of three resin cements to bovine dentin over the period of 1 year. Methods: Ten bovine dentin specimens were tested for shear Bond strength with each material (Panavia 21, Kuraray Co.; BISTITE, Tokuyama Co; MASA Bond, Sun Medical Co.) and storage mode, listed below. Four storage environments were studied as follows: water changed every day for 1 year; water unchanged for 1 year; Phosphate Buffered Saline (PBS) changed every week over 1 year; PBS unchanged for 1 year. Ten teeth were also tested for each material at 1 day as a control. The mode of failure was classified after fracture of the Bonds by SEM observation. The means of the Bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test ( p U test. Results: Although there was no statistical difference in the mean Bond strengths between the water and PBS storage solutions ( p >0.05) in all cements, the results for the shear Bond strengths in the changed storage solution groups were significantly lower than those where the storage solution remained unchanged ( p p Significance: The storage condition influenced the long-term Durability of dentin Bonding with resin cements.

Xiao Ling Zhao - One of the best experts on this subject based on the ideXlab platform.