• Title/Summary/Keyword: 유변특성

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Prediction of the Rheological Properties of Cement Mortar Applying Multiscale Techniques (멀티스케일 기법을 적용한 시멘트 모르타르의 유변특성 예측)

  • Eun-Seok Choi;Jun-Woo Lee;Su-Tae Kang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.28 no.2
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    • pp.69-76
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    • 2024

  • The rheological properties of fresh concrete significantly influence its manufacturing and performance. However, the diversification of newly developed mixtures and manufacturing techniques has made it challenging to accurately predict these properties using traditional empirical methods. This study introduces a multiscale rheological property prediction model designed to quantitatively anticipate the rheological characteristics from nano-scale interparticle interactions, such as those among cement particles, to micro-scale behaviors, such as those involving fine aggregates. The Yield Stress Model (YODEL), the Chateau-Ovarlez-Trung equation, and the Krieger-Dougherty equation were utilized to predict the yield stress for cement paste and mortar, as well as the plastic viscosity. Initially, predictions were made for the paste scale, using the water-cement ratio (W/C) of the cement paste. These predictions then served as a basis for further forecasting of the rheological properties at the mortar scale, incorporating the same W/C and adding the cement-sand volume ratio (C/S). Lastly, the practicality of the predictive model was assessed by comparing the forecasted outcomes to experimental results obtained from rotational rheometer.

  • https://doi.org/10.11112/jksmi.2024.28.2.69 인용 PDF

The electrical and rheological properties of zeolite based electrorheological (ER) Fluids (제올라이트 분말을 기본 재료로한 전기유변유체의 전기 및 유변학적 특성)

  • Jeong, Dong-Un;Choe, Yun-Dae;Kim, Sang-Guk
    • Korean Journal of Materials Research
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    • v.4 no.2
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    • pp.213-218
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    • 1994

  • 제올라이트 분말을 기본재료로 하는 전기유변유체의 전기 및 유변학적 특성이 연구되었다. 전기장 인가시 높은 한계응력을 얻기 위하여 비교적 유전상슈가 큰 5종류의 유전유체를 선택하여 제올라이트 분말과 혼합하여 전기유변유체를 준비하였다. Couette형 rheometer를 이용하여 유변유체의 한계응력을 인가된 전기장 및 온도의 함수로서 측정하였다. 이중 chlorinate hydrocabon oil과 제올라이트 분말을 혼합한 전기유변유체의 한계응력은 6KPa(E=4KV/mm, T=$25^{\circ}C$)로서 최대치를 기록하였다. 측정된 한계응력은 온도가 상승하면 점차 감소하는 반면 전류밀도는 온도에 따라 증가하였다. 전류밀도에 대한 Arrhenius 그라프에서 전기전도에 대한 활성화 에너지는 약 0.7eV였으며 이는 제올라이트 분말에 포함된 $Na^{+}$ 이온의 확산에 기인하는 것으로 분석되었다.

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Time-Dependence of the Rheological Properties of Concentrated PVA Solution in DMSO (고농도 폴리비닐 알코올/디메틸 설폭사이드 용액의 유변학적 특성의 시간의존성)

  • 김남희
    • The Korean Journal of Rheology
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    • v.9 no.3
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    • pp.118-123
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    • 1997

  • 검화도와 분자량이 상이한 폴리비닐 알코올을 디멜틸 설폭사이드에 녹여 폴리비닐 알코올/디멜틸 설폭사이드 용액을 준비하고 동적 유변학적 특성에 대한 시간과 온도 의존성 을 고찰하였다. 고농도 폴리비닐 알코올 용액의 유변학적 특성은 시간 의존성을 보여주었다. 복합점도와 저장탄성률은 시간에 따라 증가하였다. 또한 저장 탄성률과 손실탄성률의 그래 프에서 저장탄성률은 신간에 따라 증가하였으나 기울기는 시간에 따라 증가하였다. 또한 저 장탄성률과 손실탄성률의 그래프에서 저장탄성률은 시간에따라 증가하였으나 기울기는 시간 에 따라 감소하였다. 유변학적 특성의 시간 의존성은 분자량이 높을수록, 측정온도가 높을수 록 더 두드러지게 나타났다.

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Thermal and Rheological Characteristics of Paraffin Based Fuel on Aluminum Particle Size for Hybrid Rocket Application (하이브리드 로켓용 파라핀/알루미늄 연료의 알루미늄 입자크기에 따른 열적·유변학적 특성 연구)

  • Han, Seongjoo;Kim, Jinkon;Moon, Heejang;Kim, Junhyung;Ko, Seungwon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.2
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    • pp.108-114
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    • 2018

  • In this study, the thermal and rheological characteristics of a 10 wt.% addition of aluminum particles and the effect of the particle size were investigated to qualitatively analyze the paraffin fuel entrainment regression rate. The results revealed that the addition of aluminum particles and their relative particle size affected the rheological characteristics, rather than the thermal characteristics. Moreover, it was found that the variation of thermal properties had a minor effect on the entrainment regression rate, in comparison to the variation in rheological properties.

  • https://doi.org/10.6108/KSPE.2018.22.2.108 인용 PDF KSCI

Prediction of Rheological Properties of Cement-Based Pastes Considering the Particle Properties of Binders (결합재의 입자특성을 고려한 시멘트 기반 2성분계 페이스트의 유변특성 예측)

  • Eun-Seok Choi;Jun-Woo Lee;Su-Tae Kang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.6
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    • pp.111-119
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    • 2023

  • Recently, a variety of new cement-based materials have been developed, and attempts to predict the properties of these new materials are increasing. In this study, we aimed to predict the rheological properties of binary blended pastes. The cementitious materials used in the study included Portland cement (PC), fly ash (FA), blast furnace slag (BS), and silica fume (SF). The three binder components, fly ash, blast furnace slag, and silica fume, were blended with cement as the foundational composition. We predicted the yield stress and plastic viscosity of the pastes using the YODEL (Yield stress mODEL) and Krieger-Dougherty's equation. The predictive model's performance was validated by comparing it with experimental results obtained using a rheometer. When the rheological properties of the binary blended paste were predicted by reconstructing the properties and parameters used to predict the individual materials, it was evident that the predictions made using the proposed method closely matched the experimental results.

  • https://doi.org/10.11112/jksmi.2023.27.6.111 인용 PDF