膏体流变参数影响机制及计算模型

首先对膏体物料特性开展量化表征研究,通过分析膏体细观结构的物质组成,提出了一种全面描述物料特征的综合指标——固体填充率;开展膏体流变实验,基于宾汉模型对流变曲线进行拟合获得相应的屈服应力及塑性黏度,分析了体积分数、质量加权平均粒径、不均匀系数、细颗粒及水泥质量分数等因素对流变参数的影响规律,并从细观结构的角度对其影响机制进行了解释,最终构建了流变参数关于固体填充率的计算模型.研究结果表明:相同条件下,膏体屈服应力及塑性黏度随体积分数增大呈指数增大,随物料不均匀系数增大而减小,随细颗粒含量增大呈先减小再增大的变化趋势.

Influence mechanism and calculation model of CPB rheological parameters

First, the quantitative characterization of cement paste backfilling ( CPB) material characteristics was studied, and a comprehensive index called solid filling rate was presented to describe the interaction of material characteristics, through analyzing the substance composition of CPB microstructure. Then, rheological experiments were made to get the corresponding rheological curves, which were fitted by the Bingham model to get the yield stress and plastic viscosity of CPB. The influence of material characteristics such as volume fraction, weighted average grain diameter, nonuniform coefficient, the mass fraction of fine particles and cement on CPB rheological parameters was analyzed, and its mechanism was explained from the view of microstructure. At last, a calculation model of rheological parameters including solid filling rate was constructed. The results indicate that under the same conditions, the yield stress and plastic viscosity increase exponentially along with the increase of volume fraction, decrease with the increase of nonuni-form coefficient, and decrease first and increase soon with the increase of fine particles.