The effect of magnetite and carbon fiber (CF) on the rheological properties of concrete was investigated to reflect and affect its engineering performance development. The rheological parameters of concrete were measured. Next, a prediction model was established to predict the change tendency in the rheological properties of concrete. Then, the correlation between rheological and mechanical properties was investigated to explore the mechanism of rheological behavior on its engineering performance. The results showed that magnetite and CF had a significant effect on the rheological behavior of concrete. When the magnetite and CF contents were 50 % and 0.5 wt%, the yield stress and plastic viscosity of concrete increased by 210.77 % and 35.88 %, respectively, compared to the control group. The physical properties of the materials, their interaction with the cement matrix and their effect on the volume fraction of the concrete system are the main factors affecting the rheological properties of concrete. Meanwhile, the prediction model established by using the nonlinear surface fitting function could effectively predict the influence of materials on the rheological behavior of concrete. The R between the predicted and measured values of yield stress could be up to 0.99. However, under the condition of large magnetite and CF content, the aggregation effect of the materials had a certain influence on the plastic viscosity of the concrete, resulting in a certain deviation between the predicted and measured values, but the R could still be up to 0.89. It indicated that the prediction model had favorable reliability and accuracy. A strong correlation existed between the rheological parameters and mechanical strength of concrete. The effect of magnetite and CF on rheological properties of concrete promoted the internal microstructure characteristics optimization of concrete to affect its mechanical properties.

中文翻译：

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含磁铁矿（Fe3O4）和/或碳纤维的水泥混凝土的流变行为表征和预测

研究磁铁矿和碳纤维（CF）对混凝土流变性能的影响，以反映和影响其工程性能的发展。测量了混凝土的流变参数。接下来，建立了预测模型来预测混凝土流变性能的变化趋势。然后，研究流变性能与力学性能之间的相关性，探讨流变行为对其工程性能的影响机制。结果表明，磁铁矿和CF对混凝土的流变行为有显着影响。当磁铁矿和CF含量为50%和0.5wt%时，混凝土的屈服应力和塑性粘度比对照组分别增加210.77%和35.88%。材料的物理性能、它们与水泥基体的相互作用以及它们对混凝土体系体积分数的影响是影响混凝土流变性能的主要因素。同时，利用非线性曲面拟合函数建立的预测模型可以有效预测材料对混凝土流变行为的影响。屈服应力的预测值和测量值之间的 R 可达 0.99。但在磁铁矿和CF含量较大的情况下，材料的聚集效应对混凝土的塑性粘度有一定影响，导致预测值与实测值存在一定偏差，但R仍可达到0.89。表明预测模型具有良好的可靠性和准确性。混凝土的流变参数与机械强度之间存在很强的相关性。磁铁矿和CF对混凝土流变性能的影响促进了混凝土内部微观结构特性的优化从而影响其力学性能。