• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.111-112
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• 2016

Waterproofing methods for applying to roof-top in the building are various, but it is not enough to development, which are simplified and low-cost method for old building. Especially, these buildings have not only a low insulation, but a disadvantage for energy. A floating floor method is necessary for this. This study performs an experimentt about bonding capacity of complex panel for waterproofing and heat insulation. The bond strength experiment is based on KS F 4716, and it is considered by bond mix proportion about panel and slab.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.321-324
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• 2006

An experimental study on the bond strength of wall-slab joint in SC(steel plate-concrete) structure was performed. Six-full scale specimens were tested. Specimens were constructed with key variables, such as, development length, location of the bar and quantity of the shear bar. The experimental results, show that as the development length and quantity of the shear bar increase, the bond strength increases. As the bars is located on the inside the stud bolt, the bond performance was highly increased compared to the bars located out of plane of the stud bolts.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.205-208
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• 2006

The use of Fiber Reinforced Polymer (FRP) bars has been gaining popularity in the civil engineering community, as an alternative material to steel reinforcement, for their noncorrosive nature and high strength-to-weight ratio. Good performance of reinforced concrete requires adequate interfacial bond between the reinforcing material and the concrete because the load applied must be transferred from the matrix to the reinforcement. Although studies on the FRP bond behavior under monotonic loading has been reported by many, there are very little work done under cyclic loading. In this paper, we present the experimental study on the bond behavior of three different types of FRP rebars subjected to four different cyclic loading conditions.

• Magazine of the Korea Concrete Institute
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• v.22 no.5
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• pp.45-54
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• 2010

• The Journal of Advanced Prosthodontics
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• v.9 no.5
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• pp.350-357
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• 2017

PURPOSE. The object of the present study was to evaluate the shear bonding strength of composite to PEKK by applying several methods of surface treatment associated with various bonding materials. MATERIALS AND METHODS. One hundred and fifty PEKK specimens were assigned randomly to fifteen groups (n = 10) with the combination of three different surface treatments (95% sulfuric acid etching, airborne abrasion with $50{\mu}m$ alumina, and airborne abrasion with $110{\mu}m$ silica-coating alumina) and five different bonding materials (Luxatemp Glaze & Bond, Visio.link, All-Bond Universal, Single Bond Universal, and Monobond Plus with Heliobond). After surface treatment, surface roughness and contact angles were examined. Topography modifications after surface treatment were assessed with scanning electron microscopy. Resin composite was mounted on each specimen and then subjected to shear bond strength (SBS) test. SBS data were analyzed statistically using two-way ANOVA, and post-hoc Tukey's test (P<.05). RESULTS. Regardless of bonding materials, mechanical surface treatment groups yielded significantly higher shear bonding strength values than chemical surface treatment groups. Unlike other adhesives, MDP and silane containing self-etching universal adhesive (Single Bond Universal) showed an effective shear bonding strength regardless of surface treatment method. CONCLUSION. Mechanical surface treatment behaves better in terms of PEKK bonding. In addition, self-etching universal adhesive (Single Bond Universal) can be an alternative bonding material to PEKK irrespective of surface treatment method.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.547-554
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• 2013

This study was intended to estimate the bond strength of steel fiber in UHPFRC through pullout test. The pullout test was carried out with the double-sided pullout specimens with multiple fibers. First, the effect of fiber density on the bond strength was investigated, and the experimental result presented that the density range considered in this study was proved not to produce fiber-to-fiber interaction. The bond strength was estimated from several methods, which are based on the pullout load or energy at peak load, and the total energy absorbed until fibers are pulled out completely. the estimated bond strength obtained from the total energy was shown to be under the influence of the embedded length of fiber. the bond strengths obtained from peak load condition was 6.64 MPa in average, which had little difference compared to 6.46 MPa calculated by peak load only. Considering simplicity of test and analysis, it may be no matter to estimate the bond strength from peak load in pullout test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.15-22
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• 2017

This study focuses on the investigation of bond strength of magnesium potassium phosphate cement mortar(MKPC) according to moisture condition of substrate. Tensile bond test, shear bond test and interfacial bond test are adopted for evaluating the adhesion characteristics of MKPC to conventional cement mortar substrate. The main experimental variables are test methods and moisture levels of substrate. Because the moisture condition of the substrate may be critical to achieving bond, optimum moisture condition for a conventional concrete substrate has evaluated in this study. The results are as follows ; The effects of moisture condition at substrate into the bonding of MKPC are less different than polymer cement mortar and epoxy mortar. But the saturated and surface dry condition is the most appropriate moisture level among the considered, followed by saturated condition and wet condition. Thus, an adequate moisture level of substrate for MKPC is essential for good bond strength.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.25-34
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• 2012

It has been well known that concrete structures exposed to acid and sulfate environments such as sewer etc. show significant decrease in their durability due to chemical attack. Such deleterious acid and sulfate attacks lead to expansion and cracking in concrete, and thus, eventually result in damage to cement mortar by forming expansive hydration products due to the reaction between cement hydration products and acid and sulfate ions. In this study, the effect of fly ash and blast furnace slag on the bond performances of structural synthetic fiber in latex modified cement mortar under sulfate environments. Fly ash and blast furnace slag contents ranging from 0 % to 20 % are used in the mix proportions. The latex modified cement mortar specimens were immersed in fresh water, 8 % sodium sulfate ($Na_2SO_4$) solutions for 28 and 50 days, respectively. Pullout tests are conducted to measure the bond performance of structural synthetic fiber from latex modified cement mortar after sulfate environments exposure. Test results are found that the incorporation of fly ash and blast furnace slag can effectively enhance the PVA fiber-latex modified cement mortar interfacial bond properties (bond behavior, bond strength and interface toughness) after sulfate environments exposure. The microstructural observation confirms the findings on the interface bond mechanism drawn from the fiber pullout test results under sulfate environments.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.495-501
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• 2009

In this paper, a numerical anchor bond-slip model is proposed to improve the numerical simulation of concrete-steel structures connected with steel anchor bolts and subjected to extreme cyclic loading. The suggested bond-slip model is composed of a group of nonlinear uniaxial connector elements and its parameters can be determined by calibrating the model with pull-out test data. Numerical analysis results from simulating a concrete foundation-steel column structure using the proposed bond-slip anchor model, which is implemented based on Abaqus elements, and the perfect-bond anchor model are compared with the experimental results. It is concluded that a reasonable anchor bond-slip model is required to realistically simulate concrete-steel structures subjected to extreme cyclic loading, and the proposed anchor bond-slip model shows acceptable performance in the present numerical analysis.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1479-1484
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• 2014

Based on the full optimized molecular geometric structures at B3LYP/cc-pvtz method, a new designed compound, 4,6,8-trinitro-4,5,7,8-tetrahydro-6H-furazano[3,4-f ]-1,3,5-triazepine was investigated in order to look for high energy density compounds (HEDCs). The analysis of the molecular structure indicates that the seven-membered ring adopts chair conformation and there exist intramolecular hydrogen bond interactions. IR spectrum and heat of formation (HOF) were predicted. The detonation velocity and pressure were evaluated by using Kamlet-Jacobs equations based on the theoretical density and condensed HOF. The bond dissociation energies and bond orders for the weakest bonds were analyzed to investigate the thermal stability of the title compound. The results show that $N_1-N_6$ bond is the trigger bond. The crystal structure obtained by molecular mechanics belongs to $Pna2_1$ space group, with lattice parameters Z = 4, a = 15.3023 ${\AA}$, b = 5.7882 ${\AA}$, c = 11.0471 ${\AA}$, ${\rho}=2.06gcm^{-3}$. In addition, the analysis of frontier molecular orbital shows the title compound has good stability and high chemical hardness.