• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.246-253
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• 2003

Although concrete members are not normally designed to resist direct tension, the knowledge of tensile strength is of value in estimating the cracking load. In general, there are three types of test method for tensile strength ; direct tension test, flexural tension test, and splitting tension test. Though direct tensile strength represents the real tensile strength of concrete, direct tension tests are seldom carried out, mainly because it is very difficult to applicate a pure tension force. The purpose of this paper is to investigate the test methods, effect of aspect ratio, and the size effect on the direct tensile strength. Direct tension test, using bonded end plates, follows RILEM and U.S.Bureau of Reclamation. And other test methods follow ASTM provisions. Four kinds of aspect ratio and two kinds of size effect are tested. Same variables are tested by direct tension test and splitting tension test for comparison between the two test methods. Test results show that direct tensile strength of concrete is more affected by aspect ratio and size than other kinds of strength.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.422-425
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• 2003

Investigated whether fiber orientation distribution of twisted yarn composites and the fiber content are 0$^{\circ}$ and 90$^{\circ}$ direction tensile strength and some correlation. Tensile strength of 0$^{\circ}$ directions of twisted yarn composites increased changelessly being proportional the fiber content and fiber orientation function get into anisotropic in isotropic. But, tensile strength ratio by separation of fiber filament of 90$^{\circ}$ directions tensile strength decreased when tensile load is imposed for width direction of reinforcement fiber. 0$^{\circ}$ and 90$^{\circ}$ direction tensile strength ratio value of a twisted yarn composites not receive almost effect of the fiber content of fiber orientation function J = 0.4 lows. Although do, 20 wt% of the fiber content is high about 0$^{\circ}$ and 90$^{\circ}$ direction tensile strength ratio about 1.6~2 than 10 wt% from J = 0.4. Therefore. could know that effect of the fiber content is dominate.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.603-610
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• 2003

The influence of Poisson's ratio on the tensile strength of brittle materials is neglected in many studies. When brittle materials are loaded in compression or impact, substantial tensile stresses are induced within the materials. These tensile stresses are responsible for splitting failure of the materials. In this paper, the state of stress in a spherical particle due to two diametrically opposed forces is analyzed theoretically. A simple equation for the state of stress at the center of the particle is obtained. An analysis of the distribution of stresses along the z-axis due to distributed pressures and concentrated forces, and on diametrically horizontal plane due to concentrated forces, shows that it is reasonable to propose the tensile stress at the center of the particle at the point of failure as a tensile strength of the particle. Moreover, the tensile strength is a function of the Poisson's ratio of the material. As the state of stress along the z-axis in an irregular specimen tends to be similar to that in a spherical particle compressed diametrically with the same force, this tensile strength has some validity for irregular particles as well. Therefore, it can be proposed as the tensile strength for brittle materials generally. The effect of Poisson's ratio on the tensile strength is discussed.

• Korean Journal of Materials Research
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• v.13 no.1
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• pp.64-68
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• 2003

The 1.6 vol% and 2.5 vol% TiNi/6061Al composites were fabricated by permanent mold casting for investigating the effect of heat treatment on tensile strength for composites. The tensile strength without T6 treatment at 293 K was increased with increasing the volume fraction of TiNi fiber and at 363 K the higher the pre-strain, the higher the tensile strength. The tensile strength of the composite with $T_{6}$ treatment at 293 K was found to increase with increasing both the amount of pre-strain and the volume fraction of TiNi fiber and was higher than that without $T_{6}$ treatment. It should be noted that the tensile strength 2.5vol%TiNi/6061Al composites rolled at a 38% reduction ratio was the maximum value of 298 MPa. The tensile strength of composites decreased with increasing the reduction ratio over 38% because of the rupture of TiNi fiber.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2374-2382
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• 2002

Aluminum alloy/aramid fiber reinforced plastic(Al/AFRP) laminates consists of high strength metal(A15052) and laminated aramid fiber with structural adhesive bond. The mixture ratio effect of epoxy resin curing agent accelerator on the tensile strength and T-peel strength characteristic in Al AFRP laminates were investigated in this study. The epoxy. diglycidylether of bisphenol A(DCEBA), It'as cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test , five kinds of Al/AFRP laminates were named as Al/AFRP(1) and three others of Al/AFRP laminates were named as Al/AFRP(2). The comparison of tensile strength and T-peel strength with variation of resin mixture ratio were studied. Respectively. Al/AFRP(1) and Al/AFRP(2) indicated approximately 6.0 times and 7.0 times more improved maximum tensile strength in comparison with those of monolithic A15052. Al/AFRP(2) indicated approximately 1.5 times more impoved maximum T-peel strengths in comparison with those of Al/AFRP(1). As results. Al/AFRP(2) turned out to have more effective characteristics on the tensile strength and T-peel strength than those of Al/AFRP(1).

• Journal of Welding and Joining
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• v.22 no.4
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• pp.50-58
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• 2004

In this study, high temperature tensile properties of high strength steels(POSTEN60, POSTEN80) were investigated. The three-dimensional thermal elastic-plastic analyses were conducted to investigate the characteristics of welding residual stresses in welds of high strength steels on the basis of thermal and mechanical properites at high temperature obtained from the experiment. According to the results, high temperature tensile strength of POSTEN60 steel deteriorated slowly to 10$0^{\circ}C$. As the temperature went up, the tensile strength became better because of blue shortness, and it deteriorated radically after reaching to the maximum value around 30$0^{\circ}C$. For the POSTEN80 steel, high temperature tensile strength deteriorated slowly to 20$0^{\circ}C$. As the temperature went up the tensile strength became better and it deteriorated slowly to $600^{\circ}C$ after reached to the maximum value around 30$0^{\circ}C$. Strain of high strength steels at the elevated temperature increased radically after the mercury rose to $600^{\circ}C$. The strain hardening ratio of POSTEN60 steel was larger then that of POSTEN80 steel at the elevated temperature as in the case at the room temperature and it became smaller radically after the mercury rose to 40$0^{\circ}C$. And, in the welding of high strength steels, increasing tensile strength of the steel (POSTEN60

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.11
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• pp.147-154
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• 2019

The purpose of this study is to evaluate the effect of admixtures as blast-furnace slag(BF) and fly ash(FA) on tensile and adhesive properties of polymer cement mortar(PCM) with EVA emulsion. The test specimens are prepared with five polymer-cement ratio(P/C) and five admixture contents, and tested for tensile strength and adhesion in tension. From the test results, the tensile strength and adhesion in tension could be improved by an appropriate combination of P/C and admixture contents. In particular, the maximum of tensile strength of PCM with P/C 10% and BF content of 10% is 4.70MPa which is about 1.55 times higher than that of plain mortar, and about 1.22 times that of PCM that does not contain any mixture. The ratio of adhesion in tension to tensile strength of PCM with admixtures averaged 55.8%. It is also apparent that admixture contents of 5% or 10% could be proposed for improvement of tensile strength and adhesion in tension of PCM.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.27-33
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• 2018

PURPOSES : The purpose of this study is to estimate the optimum content of an inorganic additive for cold-recycled asphalt mixtures and evaluate its performance. METHODS : An indirect tensile test, a tensile-strength ratio test, and an indirect tensile-fatigue test were conducted on cold-recycling asphalt mixtures with various additives. RESULTS : The laboratory performance tests indicated that granulated blast-furnace slag mixed with inorganic and cement activators provided optimum performance. The performance results of the cold-recycled asphalt pavement were similar to the inorganic and cement activators' performance in terms of the indirect tensile strength, tensile strength ratio, and indirect tensile-fatigue test. CONCLUSIONS : Overall, the performance of a cold-recycled asphalt mixture using inorganic additives and emulsion asphalt was comparable to a warm-recycled asphalt mixture. However, more experiments aimed at improving its performance and studying the effect of the inorganic additives must be conducted.

• Journal of Welding and Joining
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• v.18 no.6
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• pp.83-88
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• 2000

Variation of welded-joint hardness and tensile strength of a accelerated-cooled fine-grained ferritic-pearlitic steel with heat input was investigated. In a weld heat-affected zone, a softened zone was formed and it had lower hardness than that of a base metal. While the width of a softened zone increased continuously with an increase of heat input up to 100kJ/cm. the minimum hardness in a softned zone was almost constant after a continuos decrease up to 60KJ/cm. Because of a softened zone, the welded-joint was fractured in the HAZ and its maximum reduction of tensile strength was about 20%. Measured welded-joint tensile strength and calculated minimum tensile strength in a welded-joint was almost same, which means that the plastic restraint of a softened zone did not occur in this experiment. It is believed that as a softened zone width-to-specimen thickness ratio is as high as 2~6 in this experiment, the plastic restraint effect does not occur. Theoretical analysis shows that the plastic restraint effect occurs only when the ratio is below 0.5.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.137-142
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• 2017

PURPOSES :The objective of this study is to evaluate the performance of asphalt mixtures containing inorganic additive and a high content of reclaimed asphalt pavement (RAP). METHODS : The laboratory tests verified the superior laboratory performance of inorganic additive compared to cement, in cold recycled asphalt mixtures. To investigate the moisture susceptibility of the specimens, tensile strength ratio (TSR) tests were performed. In addition, dynamic modulus test was conducted to evaluate the performance of cold recycled asphalt mixture. RESULTS :It was determined that NaOH solution mixed with $Na_2SiO_3$ in the ratio 75:10 provides optimum performance. Compared to Type B and C counterparts, Type A mixtures consisting of an inorganic additive performed better in the Indirect tensile strength test, tensile strength ratio test, and dynamic modulus test. CONCLUSIONS : The use of inorganic additive enhances the indirect strength and dynamic modulus performance of the asphalt mixture. However, additional experiments are to be conducted to improve the reliability of the result with respect to the effect of inorganic additive.