石灰石粉对水泥-粉煤灰浆体剪切变稀和剪切增稠的影响

发布时间：2019-01-22 19:01

【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.
[Abstract]:The rheological curves of cement paste with different content of fly ash and limestone powder (mass fraction of cement) were measured by Rheolab QC rotary viscometer, and the measured data were fitted by Herschel-Bulkey (H-B) model. The results show that the rheological curves can be divided into two stages: shear thinning and shear thickening with the increase of shear rate, and the rheological behavior of pure cement paste is still shearing thinning at large shear rate. The addition of fly ash and limestone powder not only reduces the critical shear stress and the critical shear rate of cement paste, but also reduces the rheological index of slurry at all stages. The degree of shear thinning in shear thinning stage is increased and the shear thickening degree in shear thickening stage is reduced. By increasing the content of limestone powder and its specific surface area, the rheological index of the slurry increases and the shear thinning degree decreases during the shear-thinning stage, and when the content of limestone powder increases from 0% to 15%, The rheological index of the slurry increased significantly during the shear-thinning stage.
【作者单位】：中南大学土木工程学院;中南大学高速铁路建造技术国家工程实验室;中南大学重载铁路工程结构教育部重点实验室;
【基金】：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)
【分类号】：TU528

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