| 摘要: |
| 采用Rheolab QC型旋转黏度计测试了粉煤灰、石灰石粉掺量(占水泥的质量分数)不同的水泥浆体流变曲线，并采用Herschel Bulkey(H B)模型对所测数据进行了拟合处理.结果表明：随剪切速率的增大，所测浆体流变曲线可分为剪切变稀和剪切增稠两个阶段，纯水泥浆体在较大剪切速率下的流变行为仍表现为剪切变稀；粉煤灰和石灰石粉的掺入不仅降低了水泥浆体的临界剪切应力和临界剪切速率，使浆体容易出现剪切增稠，而且降低了浆体各阶段的流变指数，增大了浆体在剪切变稀阶段剪切变稀的程度，降低了浆体在剪切增稠阶段剪切增稠的程度；增大浆体中石灰石粉掺量及其比表面积，则浆体在剪切变稀阶段的流变指数增大，剪切变稀程度降低，且当石灰石粉掺量由0%增大到15%时，浆体在剪切变稀阶段的流变指数显著增大. |
| 关键词: 水泥浆体 流变性能 剪切变稀 剪切增稠 石灰石粉； 粉煤灰 |
| DOI：103969/j.issn1007 9629201505019 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划(973计划)项目(2013CB036201);中国铁路总公司重点课题(2014G012);中南大学教师科学基金项目（2014JSJJ013）；湖南省交通科技计划项目（201122） |
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| Effects of Limestone Powder on Shear Thinning and Shear Thickening of Cement Fly Ash Paste |
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XIE Youjun, CHENG Xiaobo, MA Kunlin, LONG Guangcheng
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School of Civil Engineering, Central South University, Changsha 410075, China
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| Abstract: |
| Rheological property of cement pastes with different content (mass fraction of cement) of fly ash and limestone powder was tested by rotation viscometer with type of Rheolab QC. Results show that rheological curves show both shear thinning and shear thickening with the increase of shear rate. Pure cement paste shows shear thinning even in high shear rate. Addition of fly ash and limestone powder not only decreases critical shear stress (τcrit) and critical shear rate (γcrit) of cement paste, resulting in the paste easy to shear thickening, but also decreases rheological index (n), resulting in the increase of shear thinning degree in shear thinning stage, and the decrease of shear thickening degree in shear thickening stage. With the increase of limestone powder content and specific surface area, the rheological index in shear thinning stage increase, resulting in the decrease of shear thinning degree. When limestone powder content increases from 0% to 15%, the rheological index increases significantly in shear thinning stage. |
| Key words: cement paste rheological behavior shear thinning shear thickening limestome powder fly ash |
