• Title/Summary/Keyword: Drying agent

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Drying Shrinkage Reduction of Redispersible Polymer Powder-Modified Mortars Using Powdered Shrinkage-Reducing Agent (분말수축저감제를 이용한 제유화형 분말수지 혼입 폴리머 시멘트 모르터의 건조수축 저감효과)

  • ;Ohama, Yoshihiko
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.231-236
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    • 1998
  • In general, the drying shrinkage of polymer-modified mortars using redispersible polymer powders is much higher than that of unmodified mortar. The purpose of this study is to reduce the drying shringkage of polymer-modified mortars using a redispersible poly(ethylene-vinyl acetate) (EVA) powder, which is widely used for the manufacture of prepackaged-type polymer-modified mortar products at present. Polymer-modified mortars using the redispersible EVA powder with powdered shrinkage-reducing agent were prepared with various polymer-cement ratios and shrinkage-reducing agent contents, and tested for drying shrinkage and strength. From the test results, the drying shrinkage of the redispersible EVA powder-modified mortars with a powdered shrinkage agent is remarkably reduced with increasing shrinkage-reducing agent content, and becomes approximately a half of that of the redispersible EVA powder-modified mortars with the same polymer-cement ratios and without the shrinkage-reducing agent at a shrinkage-reducing agent content of 6%.

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Study on Drying Shrinkage Properties of HPC Infilled Concrete Mixing Shrinkage Reducing Agent and Expansive Agent (수축저감제 및 팽창재를 혼입한 HPC 충전용 콘크리트의 건조수축 특성 검토)

  • Park, Ji-Woong;Ji, Woo-Ram;Shin, Ki-Don;Gao, Shan;Lee, Gun-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.9-10
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    • 2017
  • In case of the concrete is poured into the HPC(Hollow Precast Concrete) column, the shrinkage condition of the HPC surface and the infilled concrete may be different, causing an interfacial space and deteriorating the integration performance. In this study, manufacturing HPC column mold and and the drying shrinkage properties with the charging concrete were examined. As a result, case of the shrinkage reducing agent showed the best drying shrinkage reduction effect. In the case of the expansive agent, the length change was lower than that of plain, but the difference from the shrinkage reducing agent was large, so it is considered that mixing condition of expansion mixing condition should be improved.

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Effect of Admixtures on Drying Shrinkage Crack of Hardened Cement Mortar (시멘트경화체의 건조수축균열에 미치는 혼화재의 영향)

  • 이승한;이종석
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.10a
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    • pp.229-233
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    • 1995
  • In this study we have the properties of drying shrinkage crack of hardened cement mortar using admixtures. The drying shrinkage cracking test process has been examined by the restrained drying shrinkage strain by restraining rate measuring properties of strain-with- restraint by JIS original proposal and keeps a flow value of mortar about 100$\pm$5%. The results show that the usage of shrinkage reducing agent 1.5% was effective on the control of drying shrinkage in OPC and CP by restraining rate 20% and strain-with-restraing 20~30 $\mu$, the usage of expansion agent 0.45% was effective by restraining rate 50~60% and strain-with-restraint 40~80$\mu$, and the effectiveness was increased with shrinkage reducing agent. Also. admixtures such as Flyash, CP and NC reduced restrained shrinkage and drying shrinkage cracking and more with shrinkage reducing agent

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Effects of Drying Condition and Binding Agent on the Quality Characteristics of Ground Dried-Pork Meat Products

  • Choi, Yun-Sang;Ku, Su-Kyung;Park, Jong-Dae;Kim, Hee-Ju;Jang, Aera;Kim, Young-Boong
    • Food Science of Animal Resources
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    • v.35 no.5
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    • pp.597-603
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    • 2015
  • The purpose of this study was to investigate the influence of processing conditions (temperature and time) and binding agent types (glutinous rice flour, potato starch, bean flour, and acorn flour) on the physicochemical and sensory characteristics of ground dried-pork meat product. For this purpose, ground dried-pork meat product was produced by adding several binding agents at different drying temperatures and times. The drying time affected moisture content and water activity in all drying temperature. However, under the similar drying conditions, the extent of drying varied depending on the type of binding agents. The results of sensory evaluation for texture degree and overall acceptability indicated the following: overall, higher drying temperatures and longer drying time heightened the degree of texture, and the overall acceptability varied depending on binding agent type. Physicochemical and sensory characteristics were analyzed to determine any possible correlation. The results revealed a high correlation between moisture content, water activity, shear forces, and sensory evaluation (p<0.01). However, there was no correlation with respect to overall acceptability.

Improvement of Paper Bulk and Stiffness by Using Drying Shrinkage Analysis (건조수축 해석을 통한 종이의 벌크 및 강직성 향상)

  • Lee, Jin-Ho;Park, Jong-Moon
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.4
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    • pp.49-58
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    • 2011
  • The maximum drying shrinkage velocity was proposed to verify bulk and stiffness improvement mechanism during drying according to papermaking parameters. It was based on the wet-web shrinkage behavior without the restraint of wet-web during drying, so intact drying impact could be measured. Bulking agent reduced the drying shrinkage and the maximum drying shrinkage velocity, so paper bulk increased and paper strength decreased. When adding cationic starch to stock with the bulking agent for strengthening, the bulk was increased further with additional decreasing of the drying shrinkage and the maximum drying shrinkage velocity. Paper strength also increased except tensile stiffness index with decreasing the drying shrinkage and the maximum drying shrinkage velocity. When using additional strength additives for strengthening of fiber interfaces extended by bulking agent and cationic starch, amphoteric strength additive increased paper stiffness without loss of paper bulk. It was considered that the added amphoteric strength additives were cross-linked to the stretched cationic starch and this cross-linking increased elasticity of fiber-polymer-fiber interfaces without changing the drying behavior. Paper bulk could be increased with decreasing the maximum drying shrinkage velocity. The drying shrinkage of paper also could be controlled by fiber-to-fiber bonding interfaces by the bulking agent. In this case, paper strength including stiffness was decreased by reducing fiber-to-fiber bonding but it could be improved by strengthening fiber-to-fiber interfaces with polymer complex without loss of bulk.

An Experiment Study on Drying Shrinkage Reduction of Concrete Slab (슬래브 구조물용 콘크리트의 건조수축 저감에 관한 연구)

  • Sohn Yu Shin;Lee Seung Hoon;Park Chan Kyu;Kim Gyu Dong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.592-595
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    • 2004
  • This Study discusses the properties of drying shrinkage of concrete slab with W/B, water content, fiber and anti-shrinkage agent. According to results, drying shrinkage is reduced with decrease of water content and W/B. Also, compared with plain concrete, drying shrinkage is reduced by using of fiber, anti-shrinkage agent and adding ratio of anti - shrinkage agent. Therefore, in the range of workability if water content and W/B are reduced and using of fiber and anti-shrinkage agent are performed properly, crack by drying shrinkage can be prevented effectively.

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Mechanical and Chemical Conditioning Effect on Field Drying Rate and Quality of Grass Hay

  • Seo, S.;Chung, E.S.;Kim, J.G.;Kang, W.S.;Kim, W.H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.8
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    • pp.1109-1112
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    • 2000
  • A field experiment was carried out to determine the effects of mechanical and chemical conditioning at mowing on field drying rate and quality of grass hay in 1996. Mower conditioner and/or chemical drying agent $(K_2CO_3)$ were used at different harvest stages (late boot, heading and bloom stages) for hastening hay-making. After field drying, square bales were made by hay baler, and the visual estimation and nutritive value of hay were evaluated after storing two months. In mower conditioning, the duration of field drying was shortened by 0.5 to 1 day compared with drying agent, and by 1 to 2 days compared with control. The drying matter loss of hay was reduced by late harvest and mechanical conditioning. The visual score (leafiness, green color, odor and softness), and acid detergent fiber (ADF), neutral detergent fiber (NDF), in vitro dry matter digestibllity (IVDMD), and relative feed value (RFV) of hay were improved with mechanical conditioning, but chemical alone had little effect on quality. The quality of hay harvested at bloom stage was much lower than that of hay harvested at late boot and heading stage. In conclusion, mower conditioning can enhance the field drying rate of grass hay, however the drying efficiency of chemical drying agent is very low. Also the effects of chemical/mechanical combined conditioning are very similar compared with mechanical conditioning alone. Harvesting at late boot to heading stage is recommended for the production of high quality hay.

Drying Shrinkage and Pore Structure of Self-Healing Epoxy-Modified Mortars Using Expansive Admixtures (팽창성 혼화재를 병용한 에폭시수지 혼입 자기치유 모르타르의 건조수축 및 세공구조)

  • Ham, Seong-Min;Kim, Wan-Ki
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.166-167
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    • 2015
  • The purpose of this study is to examine the effect on drying shrinkage of self-healing epoxy-modified mortars(EPMMs) using expansive admixtures. The EPMMs are prepared with polymer-binder ratios of 0 and 10%, and tested for drying shrinkage and pore structure analysis. As a result, regardless of the expansion and swelling agent content, the drying shrinkage of the EPMMs is remarkably decreased than that of unmodified mortars. Also, the pore size distribution of the EPMMs is moved to smaller size in comparison with unmodified mortars. In this study, the EPMM with expansive agent 7.5% and swelling agent 2.5% is recommended as a optimal mix proportion for reduction of drying shrinkage.

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An Experimental Study on Shrinkage of High Strength Concrete with Mineral Admixture (혼화재 사용에 따른 고강도 콘크리트의 수축에 관한 실험적 연구)

  • Lee, Young-Jae
    • Journal of the Korean Society of Industry Convergence
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    • v.13 no.2
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    • pp.99-106
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    • 2010
  • The effects of additive and shrinkage reducing agent on the drying and autogenous shrinkage of high strength concrete are investigated in this study. As results, when the ratio of W/B(low water to binder ratio) increase, the compressive strength is decreased. Comparing with PC(portland cement) concrete, the strength is 2.8%, 3.2% and 3.8% lower respectively than that of PC when concrete mixing ratio is 0.2%, 0.3% and 0.4% in 28 days curing. Drying shrinkage strain of PC concrete showed $-650{\times}10^{-6}$ in 91 days curing. When SR(shrinkage reducing agent) of 0.2%, 0.3% and 0.4% is mixed, the drying shrinkage strains are 21%, 34% and 41% lower than those of PC in 91 days curing. Autogenous shrinkage strain of PC concrete appeared $-480{\times}10^{-6}$ in 56 days curing. When SR of 0.2%, 0.3% and 0.4% is mixed, the autogenous drying shrinkage strain are 12.5%, 19.8% and 33.3% lower than those of PC in 56 days curing. In cases of using the mineral and shrinkage agent or only using a shrinkage reducing agent also appeared same reducing effects for drying shrinkage and autogenous shrinkage.

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Influence of Shrinkage Reducing Agent on Drying Shrinkage of Mortar (모르타르의 건조수축에 미치는 수축저감제의 영향)

  • 이승한;정용욱;박정섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.563-566
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    • 2000
  • The study is to examine the drying shrinkage reducing method of mortar using organic shrinkage reducing agent. According to the experiment result, when 2% and 4% of organic shrinkage reducing agent were added, 40% and 50% of the shrinkage rate of mortar were obtained. Also, in the cracking test of plate-shape specimen, the usage of shrinkage agent 2% reduced about 60% of the total cracking length compare to total cracking length the usage of portland cement, the usage of shrinkage agent 4% was not happened crack until 90 days. Accordingly, the usage of shrinkage agent show good effect in prevention of crack.

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