纳米CaCO3对水泥-石灰石粉浆体流变作用

试验采用Rheolab QC型旋转黏度计测试了掺纳米CaCO₃的水泥-石灰石粉浆体的流变曲线，应用Herschel-Bulkley流变模型对其剪切应力-速度（τ-γ）曲线进行拟合，得到浆体的动态屈服应力、稠度系数和流变指数，并用触变环面积表征浆体的触变性。结果表明：随石灰石粉掺量的增加，水泥-石灰石粉浆体的动态屈服应力逐渐减小，稠度系数增大，触变性先增大后减小；纳米CaCO₃未改变水泥-石灰石粉浆体的流变类型都呈现出剪切稀化行为；随纳米CaCO₃掺量的增加，水泥-石灰石粉浆体动态屈服应力和稠度逐渐增大，触变性减小，纳米CaCO₃使水泥-石灰石粉浆体流变性能变差，但使其稳定性增强。

Rheological properties of cement-ground limestone paste with nano-CaCO3

The rheological curves of the cement-ground limestone paste were determined by Rheolab QC rotation viscometer. Dynamic yield stress, consistency coefficient and rheological index of the paste were obtained by fitting the measured τ-γ curves based on Herschel-Bulkley model and thixotropy was characterized by the area of thixotropic hysteresis loop. The results indicate that:with the increase of ground limestone content, dynamic yield stress decreases gradually, consistency coefficient increases, while thixotropy increases and then decreases. The addition of nano-CaCO₃ has little effect on the rheological type of the cement-ground limestone paste and they both present a shear thinning behavior. With the increase of nano-CaCO₃ content, dynamic yield stress and consistency coefficient increase gradually, while thixotropy decreases. The addition of nano-CaCO₃ results in a poor rheological properties of the cement-ground limestone pastes but enhances its stability.