• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.304-307
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• 2004

Direct tensile tests were carried out for the tensile members of MMA-modified polymer concrete with different steel kinds and steel diameters and steel ratios to figure out the effect of tensile strength of polymer concrete. In the experiments, MMA-modified polymer concrete with $1000\;kgf/cm^2$ of compressive strength, steel with $5200\;kgf/cm^2$ of tensile strength, and the tensile members with 100 cm of constant length were used. Experimental results showed that, regardless of steel kinds, diameters and steel content, the strain energy exerted by concrete till the initial crack was $14-15\%$ of the total energy till the point of yield: The energy was much larger than the one of high-strength cement concrete. The behaviors of tensile members of MMA-modified polymer concrete were in relatively good agreement with the model suggested by Gupta-Maestrini (1990), which was idealized by the effective tensile stress-strain relationship of concrete and the load-strain relationship of members, while those showed a big difference from CEB-FIP model and ACI-224 equation suggested for the load-displacement relationship that was defined as the cross sectional stiffness of effective axis. Modified ACI-224 model code about the load-displacement relationship for the tensile members of MMA-modified polymer concrete and theoretical equation for the polymer concrete tensile stiffness of polymer concrete suggested through the results of this study are expected to be used in an accurate structural analysis and resign for the polymer concrete structural members.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.387-390
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• 2003

Direct tensile tests were carried out for the tensile members of steel-reinforced polymer concrete with different steel diameters and steel ratios to figure out the effect of tensile strength of polymer concrete. In the experiments, polymer concrete with $1000kgf/cm^2$ of compressive strength, steel with $5200kgf/cm^2$ of tensile strength, and the tensile members with 100 cm of constant length were used. Experimental results showed that, regardless of steel diameters and steel content, the strain energy exerted by concrete till the initial crack was 14-15% of the total energy till the point of yield: The energy was much larger than the one of high-strength cement concrete. The behaviors of tensile members of steel-reinforced polymer concrete were in relatively good agreement with the model suggested by Gupta-Maestrini (1990), which was idealized by the effective tensile stress-strain relationship of concrete and the load-strain relationship of members, while those showed a big difference from CEB-FIP model and ACI-224 equation suggested for the load-displacement relationship that was defined as the cross sectional stiffness of effective axis. Modified ACI-224 model code about the load-displacement relationship for the tensile members of steel-reinforced polymer concrete and theoretical equation for the polymer concrete tensile stiffness of polymer concrete suggested through the results of this study are expected to be used in an accurate structural analysis and design for the polymer concrete structural members.

• 한국도로학회논문집
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• 제20권1호
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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.

• Advances in materials Research
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• 제6권4호
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• pp.329-341
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• 2017

The challenge of replacing conventional plastics with biodegradable composite materials has attracted much attention in product design, particularly in the tensile-related areas of application. In this study, fibres extracted from oil palm empty fruit bunch (EFB) were treated and utilized in reinforcing polyester matrix by hand lay-up technique. The effect of fibre loading and combined influence of alkali and silane treatments on porosity and water absorption parameters, and its correlation with the tensile behaviour of composites was analyzed. The results showed that tensile strength decreased whilst modulus of elasticity, water absorption and porosity parameters increased with increasing fibre loading. The composites of treated oil palm EFB fibre exhibited improved values of 2.47 MPa to 3.78 MPa for tensile strength; 1.75 MPa to 2.04 MPa for modulus of elasticity; 3.43% to 1.68% for porosity and 3.51% to 3.12% for water absorption at respective 10 wt.% fibre loadings. A correlation between porosity and water absorption with tensile behavior of composites of oil palm EFB fibre and positive effect of fibre treatment was established, which clearly demonstrate a connection between processing and physical properties with tensile behavior of fibre composites. Accordingly, a further exploitation of economic significance of oil palm EFB fibres composites in areas of low-to-medium tensile strength application is inferred.

• 한국지반환경공학회 논문집
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• 제4권3호
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• pp.51-59
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• 2003

지오셀 시스템의 사질토 지반에서의 보강효과를 규명하기 위하여 높이 대 폭비(H/W), 상대밀도, 재료의 강도, 복토의 두께를 다르게 하여 모형 재하시험을 수행하였다. 연구 결과 지오셀 시스템은 지오셀의 인장강도보다는 연결부의 강도가 작게 나타나 더 중요한 인자로 판단되었다. 모래의 상대밀도, 재료의 강도와 복토두께가 동일한 경우 모형 지오셀의 극한지지력은 높이 대 폭비(H/W)가 클수록 증가하는 경향을 나타내었으며 복토두께 변화에 따른 지지력비(BCR)는 낮은 상대밀도에서 더 크게 나타났다. 또한 모래의 상대밀도, 높이 대 폭비(H/W)와 복토두께가 동일한 경우 모형 지오셀의 재료의 인장강도가 커짐에 따라 극한지지력은 증가하였으며 인장강도의 영향은 조밀한 모래에서 더 두드러진 것으로 나타났다. 또한 복토층의 두께가 작을수록 지지력비는 큰 값을 나타내었다. 재료의 인장강도가 작은 특별한 경우에 Koerner공식의 적용은 주의가 필요할 것으로 사료된다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.129-132
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• 2001

Fiber waviness is one of manufacturing defects encountered frequently in thick composite structures. It affects significantly on the behavior as well as strength of thick composites. The effects of fiber waviness on tensile/compressive nonlinear elastic behavior and strength of thick composite with fiber waviness are studied theoretically and experimentally. FEA(Finite Element Analysis) models are proposed to predict tensile/compressive nonlinear behavior and strength of thick composites. In the FEA models, both material and geometric nonlinearities were incorporated into the model using energy density, iterative mapping and incremental method. Also Tsai-Wu criteria was adopted to predict the strength of thick composites with fiber waviness. Tensile and compressive tests were conducted on the specimens with uniform fiber waviness. It was observed that the degree of fiber waviness in composites significantly affected the nonlinear behavior and strength of the composites

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.173-178
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• 2000

New prediction model is investigated estimating splitting tensile strength and modulus of elasticity with curing temperature and aging. New prediction model is based on the model which was proposed to predict compressive strength, and splitting tensile strength and modulus of elasticity calculated by this model are compared with experimental values. New prediction model well estimated splittinge tensile strength and elastic modulus as well as compressive strength.

• 열처리공학회지
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• 제14권1호
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• pp.17-21
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• 2001

The effects of Cr content above its solubility limit and thermomechanical treatment on tensile strength and electrical conductivity of Cu-Cr alloys were studied to obtain optimum Cr content exhibiting a high tensile strength without degradation of electrical conductivity. The increase in Cr content above the solubility limit increased tensile strength of Cu-Cr alloys without deterioration of the electrical conductivity. The electrical conductivity was not affected by cold rolling. The electrical conductivity of a Cu-3.5%Cr alloy subjected to cold rolling ${\rightarrow}$ aging treatment ($450^{\circ}C{\times}1hr$) ${\rightarrow}$ cold rolling was equal to that of the alloy subjected to cold rolling ${\rightarrow}$ aging treatment. However, the tensile strength of the alloy subjected to the former thermomechanical treatment was superior to that of the alloy subjected to the latter thermomechanical treatment at all the deformation degrees.

• 구강회복응용과학지
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• 제20권1호
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• pp.1-8
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• 2004

STATEMENT OF PROBLEM: Tensile strength of metal crown cemented with provisional cement have shown clinically difference between metal abutment of implant and natural abutment. PURPOSE: This study was tested to compare the tensile strength of provisional cement on the natural abutment and metal abutment. MATERIAL AND METHODS: Out of the 20 premolars that were selected for this experiment, each 10 were prepared of abutments by chamfer and rounded shoulder margin and then duplicated to produce 20 metal abutments that were same to natural teeth. Then, crowns were fabricated to fit the total 40 natural & metal abutments to be cemented by cavitec, to be added of regular, repetitive vertical load, and to be measured of tensile strength by using Universal Test Machine. RESULTS: There was statistically significant difference in the tensile strength between the crowns cemented to the natural & metal abutments, but no statistically significant difference was observed between the chamfer and the shoulder gingival margin of the each abutments. CONCLUSIONS: Tensile strength of metal teeth is greater about 2 more times than that of natural teeth when it is cemented with Cavitec.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.373-378
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• 2002

The waterproofing system's performance is known to show a determining by complex interaction of material factors, design details, and the qualify of construction, and the waterproofing integrity of waterproofing membranes is determined by the bond to the deck and the amount of damage to the waterproofing membrane. In this research, the basic properties of waterproofing membranes on market and the tensile adhesive characteristics of waterproofing systems of concrete bridge deck have also been investigated in the view of the damages frequently reported from job site. As a results of tensile adhesive strength of waterproofing system, tensile strength is decrease with surface moisture contents except for inorganic-elastomeric liquid waterproofing membrane, and increase with strength of deck slab. Also tensile adhesive strength is generally increase in case of moisture curing of specimen because of pore structure and surface leveling. The after asphalt concrete paving tends to increase more than before those. The results of the liquid waterproofing membranes are upside-down, and the more concrete has strength, the more strength of tensile adhesive increase. The ambient temperature and the rolling temperature of asphalt concrete when application of the waterproofing membrane has considerable influence on the performance of waterproofing system.