• 펄프종이기술
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• 제48권2호
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• pp.99-105
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• 2016

The increase of wet web solid content after wet press and dry compressive strength were observed in lab study by judicious application of wood flour and starch for the old corrugated container (OCC). Pearl starch was better than cationic starch in strength development, but cationic starch was better for drainage. Application of vacuum on the mixed solution of wood flour and starch helped strength development further without loss of other properties. The effect of wood flour addition on wet web solid content improved as the wet pressing pressure increased. The use of wood flour and starch mixture improved wet web solid contents further.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.101-109
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• 2004

Ship structures is thin-walled structures and she has lots of curved platings. In these days, lots different kinds of closed-formulas are development for ultimate strength of flat plate but for curved panels, there are not enough study or papers for this field. In this study, the ultimate strength characteristics for ship curved plates are studied. The ship plating is generally subjected to combined in-plane and lateral pressure loads. In-plane loads included biaxial compression/tension and edge shear. This is first report about the developing of ultimate compressive strength for ship curved plating. A closed-form formula for predicting the ultimate compressive strength of curved plates are empirically derived by curve fitting based on the computed results. The results and insights developed in the present study will be useful for damage tolerant design of curved plated structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.192-197
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• 1996

An experimental study was performed to examine the feasibility of using silicic wastes as construction materials for civil structures, and investigate its utility as a replacement for the favored nature resource to prevent the economic loss. In order to achieve this objective, mechnical properties of concrete containing silicic wastes is tested by investigating the strength development through parameters of water-binder ratios replacement 10 percent ratio with respect to curting conditions. The effect of stringth development is investigated for curing conditions when silicic wastes of 10 percent of cement-binder ratios is containde. Comparision on compressive strength of normal concrete and concrete containing silicic wastes at 28 day is conducted. The concrete with silicic wastes have larger compressive strength than of normal concrete by about 20 percent, when cured at 80 degree. The wastes concrete using silica sand shows increased strength, fracture toughness, elastic modulus and strain than the normal concrete, although the silicic wastes concrete could be able to satisfy the generally required strength for conventional concrete structures.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.13-16
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• 2003

There is no study that application of the maturity using H.B.C and H.S.C. Also activation energy has different values according to the cement, admixture and water-cement ratio. Therefore to make accurate explanation for the effect of temperature on concrete strength development properties, it is necessary that activation energy value according to the kind of cement is reviewed. This study compares and estimates equivalent age using activation energy value obtained by this experiment and Freiesleben activation energy value with compressive strength of concrete. As the result of this study, activation energy value obtained by this study has more accurate explanation of temperature's influence on concrete strength development than Freiesleben activation energy value.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.105-107
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• 2012

This study was conducted to investigate the strength development of fly ash concrete using the strength development estimation for the ready mixed concrete for construction of nuclear reactors. The findings are as follows. First, the higher the curing temperature becomes, the shorter the setting time becomes. In addition, the compressive strength also increased as the curing temperature gets higher. The apparent activation energy derived from ASTM C 1074 showed 34.75 KJ/mol. The results of concrete strength estimation confirmed that Gompertz model formula has good accuracy.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.117-124
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• 1997

In this study, mechanical properties of type V cement concrete with different curing temperature were investigated. The tests for mechancial properties, i.e., compressive strength and modulus of elasticity, were carried out on two kinds of type V cement concrete mixes. concrete cylinders cured at 10, 23, 35 and 50℃ were tested at 1, 3, 7 and 8 days. The 'rate constant model' was used to described the combined effects of time and temperature on compressive strength development. Test results show that concrete subjected to high temperature at early age attains greater strength than concrete to low temperature but eventually attains lower later-age strength than that. With type V cement concrete, the linear and Arrhenius rate constant models both accurately describe the development of relative strength as afunction of the equivalent age.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.13.1-16
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• 2003

There is no study that application of the maturity using H.S.C and H.S.C. Also activation energy has different values according to the cement, admixture and water-cement ratio. Therefore to make accurate explanation for the effect of temperature on concrete strength development properties, it is necessary that activation energy value according to the kind of cement is reviewed. This study compares and estimates equivalent age using activation energy value obtained by this experiment and Freiesleben activation energy value with compressive strength of concrete. As the result of this study, activation energy value obtained by this study has more accurate explanation of temperature's influence on concrete strength development than Freiesleben activation energy value.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.57-60
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• 2003

Generally, normal concrete has the disadvantages of low tensile strength, low ductility and volume instability. To improve its performance, fiber reinforced cimentitious composite(FRCC) have been development. These composites are composed of cement, sand, water, a small amount of admixtures, and an optimal amount of fiber like synthetic fiber and steel fiber. This research investigates influence of sand, hybrid fiber and fiber volume fraction, and reports the test results of mechanical properties, fracture behavior and failure pattern of the FRCC. Our experiment was observed that sand mixed FRCC has lower compressive strength and higher bending strength than no sand mixed FRCC, and more steel fiber mixed FRCC has higher compressive strength and bending strength. Hybrid FRCC of steel and polypropylene had superior properties than FRCC of polypropylene only in same fiber volume fraction.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.89-92
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• 2005

Our country has experienced variations in temperature as belong to the area of the continental climate that shows four significant seasons. These occur quality of construction. As the hydration of cement processes, the strength of concrete is developed. In order to improve the quality of concrete, various conditions including temperature and humidity should be maintained appropriately and concrete itself should be cured sufficiently This paper is basic experiment for estimating influence of strength by seasonal mock-up concrete's heat of hydration and estimate relationship of compressive strength development by curing temperature. And show basic document as quality control.

• 한국농공학회지
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• 제42권2호
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• pp.99-107
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• 2000

The objective of this study are to compare the development of compressive strength of epoxy mortars used as repairing materials with respect to maturity , and to propose a model predicting strength development of epoxy mortars. A series of tests are carried out for the hardener contents of 30, 40 and 50 percentage of epoxy resin and compressive strengths are measured at the age of 6, 12, 24, 72, 120 and 168 hours respectively under the cure temperature of 0, 10, 20 and 3$0^{\circ}C$. The datum temperature is estimated by measured strengths, and the maturity is calculated with the estimated datum temperature. The compressive strength of epoxy mortars can be predicted by regression analysis from the maturity-compressive strength relationship.