• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.473-476
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• 2003

This study discusses the use of anti-shrinkage agent as the method to reduce autogenous and drying shrinkage. According to results, as for the fundamental properties of high performance concrete, fluidity and strength decrease with an increase of the adding ratio of anti-shrinkage agent, but air content increases. Compared with plain concrete, autogenous and drying shrinkage are reduced by 12~52% and 4~22% respectively upto the adding rario of anti-shrinkage agent of 2.0%. When expansive additive is added by 5.0%, they are also reduced by 38~95% and 15~50% respectively. Therefore, as expansive additive of 5.0% and anti-shrinkage agent of 1.0% are added to high performance concrete of around W/B 30%, it is considered that fluidity and strength are hardly influenced, and in addition, crack by shrinkage can be prevented effectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.183-188
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• 1997

From a viewpoint of construction cost and preserving management of pavement, a policy of domestic pavement was gradually spreaded concrete pavement rather than asphalt. But the use of concrete with ordinary portland cement has shortages, such as dry-shrinkage, low flexural strength, etc. In order to overcome these problems, the concrete pavement using CSA expansive additive (Non-Shrinkage Cement) was studied and carried out the fie이 application. As the results, we find out Non-Shrinkage Cement that was distinguished in short-term construction by increasing flexural strength, shrinkage compensating and low-heat evaluation compared with OPC concrete.

• Macromolecular Research
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• 제14권6호
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• pp.596-602
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• 2006

The effect of high-temperature spinning and poly(vinyl pyrrolidone) (PVP) additive on poly(vinylidene fluoride) (PVDF) hollow fiber membranes was investigated using differential scanning calorimetry, X-ray diffraction measurement, and scanning electron microscopy, together with the corresponding microfiltration performances such as water flux, rejection rate, and elongational strength. Using high-temperature spinning, porous hollow fiber membranes with particulate morphology were prepared through PVDF crystallization. The particulate structure of the membranes was further modified by the addition of miscible PVP with PVDF. Due to these effects, the rejection rate and strength of the fibers were increased at the expense of reduced water flux and mean pore size, which indicates that high-temperature spinning and PVP addition are vary effective to control the morphology of PVDF hollow fiber membranes for microfiltration.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.172-177
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• 1999

In this paper, the physical and electrical properties of the synthetic fluids No. 2 class Ⅶ used the insulating oils for automobile ignition coil are studied. Also, benzotriazole(BTA) as the streaming electrification suppressant additive is added to the oil, and the change of physical and electrical properties due to different BTA concentration is investigated. To investigate the electrical characteristics, the breakdown strength of each specimen by an experiment for AC breakdown and the changes of conductivity by measuring volume resistivity are analyzed. It is considered that the effective content of BTA as charge suppressant additive is about 10[ppm] from the results of AC breakdown and volume resistivity test.

• 한국세라믹학회지
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• 제20권3호
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• pp.217-226
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• 1983

Adquate amount of calcia was added to the regent-grade Zirconia body. Here the amount and the form of calcia were 7-21 mol% and regent-grade calcium cabonate respectively. The specimens were fired at 175$0^{\circ}C$ for 0, 3, 5 and 7 hours respectively. The phase Strength X-ray diffraction analysis and Scaning electron microscopy. The results were as follows (1) As the additive amount of calcia was increased the firing linear shrinkage apparent density compressive strength and modulus of rupture decreased but the apparent porosity increased. (2) The specimens soaked and containing calcia displayed the grain growth. (3) Monoclinic and cubic zirconia were seen in the sepcimens containing 7 mol% calcia. When without soaking the specimens containing 7-10 mol% calcia had the volume change by monoclinic$\rightleftharpoons$tetragonal transformation. (4) The lattice parameter increased according as the calcia additive was increased. The specimens containing above 19mol% calcia had the costant lattice parameter. The value of that was from 5.1264 to 5.1396 $\AA$ in the case of 7 hours soaking.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1414-1416
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• 1997

The electrical breakdown characteristics of the synthetic fluids No.2 of KS class VII used for insulating and cooling the materials for the ignition coil are studied. Also, Benzotriazole(BTA) as the streaming electrification suppressant additive is added to the oil, and the change of electrical properties due to different BTA concentration is investigated. To investigate the electrical characteristics, the breakdown strength of each specimen by an experiment for AC breakdown are analyzed. The breakdown strength of specimen by adding BTA is higher than virgin specimen in low e region, but lower than that in high region because of melting BTA. It is considered that the effective content of BTA as charge suppressant additive is about 10[ppm] from the results of AC breakdown.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.599-605
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• 1999

An experimental investigation was carried out to study the feasibility of using the stabilized sludge, as a backfill and cutoff-water materials for embanckment structures. for stabilizing of sludge, hydrated lime and quick lime was used as additive , and a series of tests was performed on the sludge and the stabilized sludge to examine their physical properties, compaction, compressive strength, hydraulic conducivity and consolication characteristics. From the test results, the physical and mechanical properteis of the stabilized sludge weremore improved as compared with the sludge. Especially from the viewpoint of physical porperty , consolidation or settlement and cutoff-water , quick lime is more effective than the hydraged lime as tabilizatio addtivie. But , viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as stabilization additive. As a result of this study, it was founded that the stabilized sludge can be developed the backfill and cutoff-water materials , improved the stabilizing method of sludge.

• 한국농공학회지
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• 제41권6호
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• pp.97-104
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• 1999

An experimental investigation was carried out to study the feasibility of using the stabiliozed sludge, as a backfill and cutoff-water materials for embankment structures. For stabilizing of sludge, hydrated lime and quick lime were used as additive, and a series of tests were performed on the sludge and the stabilized sludge to examine their physical and mechanical properties , compaction, compressive strength, hydraulic conuctivity and consolidation characteristics. From the test results, physical and mechanical properties of the stabilized sludge were improved as compared with the sludge. Especially from the viewpoint of physcial property, consolidation or settlement and cutoff-water, quick lime is more effective than the hydrated lime as a stabilization addtive. But, viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as a atabilization additive. As a result of this study, it was found that the stabilized sludge can be developed the backfill and cutoff-water materials, improved the stabilizing method of sludge.

• 한국세라믹학회지
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• 제43권8호
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• pp.458-462
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• 2006

A simple pressing process using a SiC powder, $Al_2O_3-Y_2O_3$ sintering additive, and polymer microbeads for fabricating cellular SiC ceramics is demonstrated. The strategy for making the cellular ceramics involves: (i) forming certain shapes using a mixture of a SiC powder, $Al_2O_3-Y_2O_3$ sintering additive, and polymer microbeads by pressing; (ii) heat-treatment of the formed body to burn-out the microbeads; and (iii) sintering the body. By controlling the microsphere content and sintering temperature, it was possible to adjust the porosity in a range of 16% to 69%. The flexural and compressive strengths of cellular SiC ceramics with $\sim$40% porosity were $\sim$60 MPa and $\sim$160 MPa, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.585-588
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• 2006

This paper presents experimental results for durability performance of GFRP composite exposed to the $80^{\circ}C$ alkali solution. A total of 280 specimens for 4 types of additive and 7 cases of immersion time were prepared and tested. Additives used in this study were PVA, kaolin clay, and alumina powder. Specimens were immerged up to 30 days and tested for tensile strength for each immersion time. The results indicate that it is important to fill the inner space of GFRP composite densely to avoid the decrease of tensile strength. In this study, PVA additive showed better performance than other additives.