• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.4 s.117
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• pp.61-67
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• 2006

The effect of several inorganic flame-retardants such as ammonium phosphate, ammonium sulfate, aluminum hydroxide and antimony trioxide on the flame-retardant property and tensile strength of paper has been investigated. Flame-retardants were used preferably as a dry powdered mixture and added to the furnish. Both dipping and coating treatments were employed to apply flame-retardants to paper Flame-retardant paper was manufactured by treatment of $5{\sim}30%$ flame-retardants by weight of the paper on a dry weight. Paper's flame-retardant property and tensile strength were examined by comparison of char length and tensile index. As dosages of flame-retardant chemicals increased, flame-retardant property was improved but tensile index was decreased.

• Elastomers and Composites
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• v.52 no.1
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• pp.1-8
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• 2017

Hydrolysis resistance and mechanical property changes of polyketone (POK)/glass fiber (GF) composites were investigated for GF concentrations varying between 30 and 50%. The hydrolysis resistance of GF filled POK and polyamide66 (PA66, hydrolysis resistant grade) composites were compared. As shown by the experimental results, increasing the immersion time of the composites in a monoethylene glycol (MEG)/water solution at $120^{\circ}C$ had no impact or resulted in slightly decreased mechanical properties such as the tensile strength, tensile modulus, and strain at break in case of POK composites, whereas the mechanical properties of PA66 composites showed a significant drop. Increasing GF concentrations increased the tensile strength, tensile modulus, flexural strength, and flexural modulus of POK composites; however, impact strength did not show significant changes. Hydrolysis mechanisms of POK and PA66 are discussed.

• Journal of the Korea Institute of Building Construction
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• v.2 no.1
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• pp.163-169
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• 2002

In this study, there are kind of property experiments like fluidity, compressive strength, bleeding measurement, concrete sink for CFT use high fluidity concrete. The property difference between before transmit and after transmit concrete in the mock up test with ready mixed concrete equipment is examined. The variable factors in mock up are diaphragm existence and nonexistence, diaphragm placing hole sizes. To investing the concrete Property under diaphragm, concrete packing ability, hydration heat, core specimen strength tests are performed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.26-27
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• 2015

The purpose of this study was to investigate the compressive strength property into concrete using rice straw ash.. In an effort to evaluate the effects of rice straw ash as mineral admixture, rice straw ash was mixed with cement at the mixture ratio of 0, 5, 10 and 15% relative to the cement weight. When the mixture ratio of rice straw ash was 10%, the highest compressive strength was observed, while the strength tended to decrease when the mixture ratio of rice straw ash was 15% even if it exhibited higher compressive strength than the plain. And it was observed that compressive strength of concrete containing rice husk ash was a similar a compressive strength of concrete containing silica fume.

• Computers and Concrete
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• v.11 no.6
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• pp.531-539
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• 2013

An experimental investigation of mechanical properties of jute fiber-reinforced concrete (JFRC) has been reported for making a suitable construction material in terms of fiber reinforcement. Two jute fiber reinforced concretes, called jute fiber reinforced normal strength concrete (JFRNSC) and jute fiber-reinforced high-fluidity concrete (JFRHFC), were tested in compression, flexure and splitting tension. Compressive, flexural and splitting tensile strengths of specimens were investigated to four levels of jute fiber contents by volume fraction. From the test results, Jute fiber can be successfully used for normal strength concrete (NSC) and high-fluidity concrete (HFC). Particularly, HFC with jute fibers shows relatively higher improvement of strength property than that of normal strength concrete.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.275-282
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• 2009

The effects of surface treatment method of reinforcing fiber on the bonding strength between carbon fiber reinforced polymer rebar (CFRP rebar) and high strength concrete have been evaluated in this study. The structural PVA fiber is coated with a proprietary hydrophobicoiling agent and crimped type polyolefin based structural synthetic fiber is deformed with a geometrical modification were used for the reinforcing fiber. The compressive tests have been performed to evaluate the strength property of high strength concrete depending on the surface treatment method of fiber. The bonding property between the high strength concrete and the CFRP rebar was evaluated by means of direct bonding test. The test results indicated that the surface treatment method of fiber effect on the bonding behavior of high strength concrete and CFRP rebar. Also, as the development and propagation of splitting cracks were controled by adding fibers into the high strength concrete, the bonding behavior, bond strength and relative bonding strength of CFRP rebar and high strength concrete were significantly improved.

• Journal of Technologic Dentistry
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• v.35 no.4
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• pp.353-358
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• 2013

Purpose: This study was observation shear bonding strength by compositional change and firing step of a Ni-Cr alloy for porcelain fused metal crown. The aim of study was to suggest the material for firing step of Ni71-Cr14 alloy to development of alloy for porcelain fused to metal crown. Methods: The test was on the two kinds of Ni-Cr alloy specimens. The surfaces of two alloys were analyzed by EDX in order to observe oxide characteristic. And the shear test was performed by MTS. Results: The surface property and oxide characteristic analysis of oxide layer, weight percentage of Element O within $Ni_{71}Cr_{14}$ alloy measured 23.32wt%, and $Ni_{59}Cr_{24}$ alloy was measured 23.03wt%. And the maximum shear bonding strength was measured 58.02MPa between $Ni_{59}Cr_{24}$ alloy and vintage halo(H4 group). Conclusion: The surface property and oxide characteristic three kind of Ni-Cr alloy was similar. and shear bonding strength showed the highest bonding strength in H4 specimens.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.2
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• pp.67-73
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• 2016

When assessing crack initiation of fiber reinforced concrete, usually tensile strength or flexural strength is becomes indicator, but also depend on the curing effect take place during the production of specimen. In general, after conducting concrete specimen is cured by water at temperature $20{\pm}3^{\circ}C$ in laboratory, and accomplished the assessment of strength, but most of concrete structure is kept in drying condition after moist curing through the prescribed period. However, unlike these trends that technological advances have been made, influence of the difference of curing method on crack strength is not yet clear. Therefore, in this study, it is examined on the effect of curing methods affecting the mechanical property of fiber reinforced concrete, especially crack strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.56-57
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• 2013

In this study, in regard to concrete considering variety of admixture content rate, we evaluated property of adiabatic temperature rise. By setting up high temperature history, we evaluated effect to compression strength property of high strength concrete by early high temperature history. As a result, early high temperature history accelerated Hydration reaction of cement and contribute early strength development but it didn't accomplish performance objective in long-term aged.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.61-67
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• 2001

In this study the electrical and mechanical characteristics of PET films ore analyzed after plasma surface treatment. After plasma treatment, the surface potential decay, surface potential and dielectric property were evaluated to analyze the electrical insulating property, and the tensile strength was measured as the mechanical characteristic. When plasma treatment was conducted for less than 10 minutes, it was found that the electrical insulating property was improved through evaporation of low molecular weight materials md cleaning of surface. However, for more than 10 minutes, the insulating property of plasma treated PET films was decreased due to excessive discharge energy. The tensile strength was hardly changed by Plasma treatment.