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Reduction of Drying Shrinkage of Mortar and Concrete by Expansion of Rapid Cooling Slag Fine Aggregate (급냉 슬래그 잔골재의 팽창성을 활용한 모르타르 및 콘크리트의 건조수축저감에 관한 연구)

Lee, Dong-Gyu;Min, Kyung-Hwan;Jeong, Yong-Wook
- Journal of the Korea Academia-Industrial cooperation Society
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- v.16 no.5
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- pp.3511-3517
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- 2015
It is necessary to maximize the durability of Concrete for the underground structure because its maintenance and reinforcement are difficult. For cracks due to drying shrinkage of the concrete on the characteristics of the material, there is a need for an alternative in the deterioration phenomenon that occurs. In this study, fundamental properties including drying shrinkage of mortar and concrete were investigated to replace fine aggregate from cooling slag for reducing drying shrinkage of mortar and concrete. In the case of rapid cooling slag fine aggregate, it was effective to reduce and restrain initial shrinkage of mortar and concrete, and compressive strength was increased through the all specimen in proportion to its replacement ratio.
https://doi.org/10.5762/KAIS.2015.16.5.3511 인용 PDF KSCI

Effect of Drying Methods on the Field Drying Rate and Quality of Alfalfa and Spring Oats Hay (건조방법별 알팔파와 봄 연맥의 건초조제 효과)

Seo, Sung;Kim, Jong-Geun;Chung, Eui-Soo;Lee, Jong-Kyong;Kim, Won-Ho;Shin, Dong-Eun
- Journal of The Korean Society of Grassland and Forage Science
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- v.21 no.2
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- pp.67-74
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- 2001
A field experiment was carried out to determine the effects of chemical/mechanical treatments at mowing on the field drying rate and hay quality of alfalfa(Medicago sativa L., cv. Vernal) and spring oats(Avena satvia L., cv. Swan). The chemical drying agent of 2% $K_2CO_3$, mechanical mower conditioning, and no treatment(control) were treated for hastening hay-making in the spring of 1997. The forages were harvested at early bloom stage in alfalfa and heading stage in oats. After field dry, square bales were made by hay baler, and the dry matter(DM) loss, visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rates of alfalfa and oats were high at mechanical treatment, but the drying effectiveness of chemical agents alone was very low. With mower conditioning, the duration of field dry was shortened by 1 day compared with control. therefore, mower conditioning enhance the field drying rate of alfalfa and oats. The DM loss of alfalfa and oats hay was reduced by mechanical treatment, but the efficiency by chemical alone was low. The visual score(leafiness, green color, odor and softness) of hay at mechanical treatment was slightly higher than that of chemical and control. The nutritive value(ADF, NDF, in vitro digestibility, and relative feed value) of hay was also high with treatment of mechanical, but those of chemical alone were similar compared with control. The nutritive value of hay after two months in both alfalfa and oats was decreased when compared with at harvest.
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