• 한국가구학회지
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• 제12권1호
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• pp.21-26
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• 2001

This study was carried out to get some basic information on mechanical properties of Platanus orientalis L. for the rational utilization of this wood. Relationship of anatomical characteristics with compression strength parallel to grain was analyzed using stepwise regression technique. All possible combination of 8 independent variables were regressed on compression strength parallel to grain. The summarized results in this study were as follows: 1. The compression strength parallel to grain increased with the increase of wood fiber length and wood fiber width. The strength, however, decreased with increase of number of pore per $\textrm{mm}^2$ and tangential diameter of pore. 2. The major factors affecting compression strength parallel to grain in heartwood were length of wood fiber and number of pore $per{\;}{\textrm{mm}^2}$ but width of wood fiber and length of vessel element were the important factors in sapwood.

• 콘크리트학회논문집
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• 제11권4호
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• pp.137-145
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• 1999

The use of steel fiber reinforced to improve the strength and flexural toughness of concrete is well known, but reinforcement of polymer concrete with steel fibers has been hardly reported till now. Polymer concrete has high strength, durability and freeze-thaw resistance than that of cement concrete, but it has disadvantage such as low flexural toughness. In this paper, the strength characteristics and flexural toughness of steel fiber reinforced polymer concrete are investigated experimentally with various steel fiber aspect ratios($\ell$/d), and contents(vol.%). As the result, the flexural and splitting tensile strengths and flexural toughness were increased aspect ratio, and reach the maximums at a aspect ratio of 50. The relationship between the compressive, flexural and splitting tensile strength were high. And the relationship between flexural strength and strain energy was approximately linear.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.96-97
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• 2020

In this study, the compressive strength and porosity characteristics of cement mortar mixed with liquid and powder composite water repellent were evaluated. When the liquid water repellent was mixed, the compressive strength at 28 days of age was 42% compared to OPC, and the compressive strength was greatly reduced. However, the 28-day compressive strength of the powder water repellent mixture and P5L1, P6L1 liquid and powder composite water repellent was about 97% compared to OPC, and there was little decrease in compressive strength.

• Journal of Welding and Joining
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• 제22권4호
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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

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.844-851
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• 2009

A soil mixture with low permeability and bentonite as an additive has been highly utilized as a cutoff material in landfills, banks, and dams. Even though it is anticipated that the water can seep through shear failures in the filter layer due to external loads and embankment loads during construction, usually only the coefficient of permeability of the soil mixture is considered rather than the changes of strength from the different amounts of additives. Therefore, the amount of bentonite was changed between 0%~4% in the soil mixture of the bed material to conduct a series of unconfined compressive strength, tensile strength, and shear strength tests on a specimen in order to study the characteristics of the strength. In the result, the unconfined compressive and tensile strength were increased along with the increased amount of bentonite in the low water content; however, the tensile strength in the consolidated-drained shear test generally showed similar values without significant changes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.312-316
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• 1996

Flexural fatigue strength of reinforced concrete members can be controlled by fatigue characteristics of concrete and reinforcing bars because the reinforced concrete members are composite members consisted of the concrete and the reinforcing bars. Since the fatigue characteristics of the reinforcing bars are different from static strength characteristics of those, it is necessary to obtain the fatigue characteristics of reinforcing bars directly from fatigue test. In this paper, the fatigue characteristics like fatigue strength of reinforcing bars with different diameters and different yield-strengths are obtained experimentally and the analysis and comparison of fatigue test results are presented. For the experiment, most widely used reinforcing bars manufactured by two domestic companies were randomly selected and direct tension fatigue tests were performed.

• 한국지반공학회논문집
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• 제18권4호
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• pp.75-83
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• 2002

본 연구에서는 준설토, EPS 그리고 고화재를 혼합한 경량혼합토의 역학적 특성을 일축 및 삼축압축시험을 통하여 고찰하였다. 역학적 특성은 다양한 준설토의 초기 함수비, EPS 함유율, 시멘트 함유율 그리고 양생압력에 대한 경량혼합토의 압축강도에 대하여 연구하였다. 삼축압축상태에서 EPS를 함유한 경량혼합토의 압축강도는 유효구속압에 의존 하지 않는 것으로 나타났다. EPS 함유율이 감소할수록($A_E$<2%) 그리고 시멘트 함유율이 증가할수록($A_c$>2%) 삼축압축강도-변형 거동특성은 극한 압축강도를 지나 급격한 압축강도의 감소를 보이는 시멘트 혼합토의 압축강도-변형 거동특성과 유사한 것으로 나타났다. 200kpa 이상의 압축강도를 요구하는 개량지반에 본 경량혼합토를 적용하는 경우에서 적절한 준설토의 초기함수비, EPS 함유율은 각각 약 165%~175%이상 그리고 3%~4%이상으로 제시할 수가 있었다. 삼축 및 일축압축상태에서 극한 압축강도는 시멘트 함유율이 2%이상에서 거의 증가하지 않음으로서 한계 시멘트 함유율은 2%로 제시할 수가 있었다.

• 토지주택연구
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• 제3권3호
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• pp.287-297
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• 2012

보통포틀랜드시멘트(OPC)와 고로슬래그 및 플라이애시 만으로 설계기준압축강도 80MPa의 3성분계 고강도콘크리트(이하 고강도콘크리트)를 개발하기 위하여, 고로슬래그와 플라이애시의 대체율이 고강도콘크리트의 경화전 후 재료물성 변화에 미치는 영향을 평가하였다. 고강도콘크리트의 경화전후 재료물성 평가결과, 고로슬래그와 플라이애시 대체율이 최대 30%까지 증가할수록 유동성과 장기강도가 우수한 것으로 나타났다. 또한 OPC만으로 제작된 시험체와 비교하여 길이변화 특성이 우수하며, 혼화재 사용에 따른 탄산화는 없는 것으로 나타났다. 고강도콘크리트 재료물성 평가결과, 고로슬래그 대체율 25%, 플라이애시 대체율 15%일 경우, 경화전 후 재료물성이 가장 우수한 것으로 나타났다. 이 연구결과는 향후 고가의 실리카퓸을 대체할 수 있는 고강도콘크리트의 개발에 유용하게 활용될 수 있을 것으로 기대된다.

• 전기학회논문지
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• 제59권4호
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• pp.693-699
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• 2010

General transformer's life is known as paper insulation' life. If a transformer is degraded by these aging factors, it is known that electrical, mechanical and chemical characteristics for transformer's oil-paper are changed. When the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. The paper breakdown is accompanied by an increase in the content of furanic compounds within the dielectric liquid. In this paper it is aimed at analysis on correlation between aging characteristics for insulating diagnosis of thermally aged paper. For investigating the accelerated aging process of oil-paper samples accelerating aging cell was manufactured for estimating variation of paper insulation during 500 hours at $140^{\circ}C$ temperature. To derive the results, it was performed analysis such as tensile strength(TS), depolymerization(DP), dielectric strength(DS), relative permittivity, water content(WC) and furan compound(FC) for aged paper. Also for analyzing correlation between insulating degradation characteristics, we used linear regression method. As as results of linear regression analysis, there was a close correlation between TS and DP. WC, FC. But dielectric strength was a weak correlation with aging time.

• 보존과학회지
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• 제34권4호
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• pp.295-303
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• 2018

The application of reinforcing agents with hydraulic property and strength development characteristics was studied under conditions similar to those of mural-painting mortar made with oyster shell powder. Reinforcement mortar made with oyster shell powder showed hydraulic properties and strength to supplement the weaknesses of natural hydraulic lime(NHL); this confirmed its possibility as a wall-reinforcing material with enough strength for preserving mural paintings. Reinforcement mortar 1 showed hydraulic property and general characteristics of lime mortar, such as consistency and viscosity, as well as lower strength and higher whiteness compared to an NHL product. For Reinforcement mortar 2, the original wall sample characteristics were reflected by mixing more shell produced through calcination; and it showed similar strength to that of Reinforcement mortar 1 as well as high whiteness. In measuring the contraction ratio of reinforcement mortar samples, Reinforcement mortar 1 and 2 showed more stability in property change compared to the NHL Group.