高延性水泥基复合材料的流变特性和纤维分散性

Rheological property and fiber dispersion of high ductility cementitious composites

为了研究高延性水泥基复合材料（HDCC）流变特性对短切聚乙烯醇（PVA）纤维分散性的影响规律，采用流变仪和荧光显微分析技术分别对HDCC浆体的流变特性以及短切PVA纤维在HDC C基体中的分散性进行研究．实验结果表明：HDC C浆体流变行为符合赫切尔巴尔克模型，浆体流动后，应变梯度随应力增量按幂指数增长；当HDCC浆体塑性黏度为1.3～7.3 Pa·s时，即使短切PVA纤维的体积掺量为1.5％～2.0％，纤维在HDCC 基体中的分散系数均大于0.92，实现了均匀分散．合理调整配比中粉煤灰、减水剂和功能性组分的掺量，可调控HDCC浆体塑性黏度并实现短切PVA纤维的均匀分散，为HDCC高延性的理论设计提供实验支持．

In order to investigate the influence of rheological property of high ductility cementitious composites （HDCC）on the dispersion of domestic short polyvinyl alcohol （PVA）fiber,rheometer and fluorescence microscopy technology are used to study the rheological properties of HDCC and the fiber dispersion of PVA fiber in HDCC,respectively.The experimental results reveal that the rheological behavior of HDCC slurry conforms to the Herschel-Bulkley model,in which the shear strain rate exponentially increases with the increment of the shear stress after flowing.Furthermore, when the plastic viscosity of HDCC slurry is around 1.3 to 7.3 Pa·s,even though the volume dosage of short PVA fiber is 1.5% to 2.0%,the dispersion coefficient is also more than 0.92.Thus, the short PVA fiber is dispersed in the HDCC matrix homogenously.Therefore,by reasonably regulating the content of fly ash,superplasticizer and functional components,plastic viscosity of HDCC mortar can be controlled and homogeneous distribution of PVA fibers can be achieved,which provides an experimental support for high ductility design of HDCC.