## 3 Results and Discussion
### Rheological Property Analysis
#### 3.2.1 Rheology Model Fitting and Initial Rheological Parameters  
Figure 5a shows the flow curves of the shear stress versus shear rate for Control group samples. The shear stress of the sample increased with the increase in shear rate in a range of 0 to 100 s\({}^{-1}\) under different conditions, and the curve had a clear trend of an increasing slope at a high shear rate from 80 to 100 s\({}^{-1}\), which indicates that the slurry was a typical shear-thickening fluid. Moreover, the relationship curves between shear stress and shear rate in the descending slope section of the DSPB slurry fit the Herschel-Bulkley model well, indicating that the DSPB was a non-Newtonian fluid with yield stress. Because the DSPB exhibited distinct shear-thickening behavior with measurable yield stress, this aligns with the H-B model's capacity to describe both yield stress and power law behavior simultaneously. The correlation coefficients (R\({}^{2}\)) of all the fitted results were >0.99, with an R\({}^{2}\) of 0.996 and 0.998. The dependence of viscosity on shear rate is also another rheological property of non-Newtonian fluids. Apparent viscosity is the ratio of shear stress and shear rate acting on the fluid, reflecting the internal structure of the sample to resist deformation and impede the flow characteristics. The smaller the value, the easier the flow. The shear-thickening characteristics of the DSPB slurry were more significantly characterized under the viscosity curve. Figure 5: (**a**) Shear cycle of the Control group fitted with the Herschel–Bulkley model; (**b**) viscosity profile of the Control group. Figure 5b shows the relationship between the apparent viscosity of the Control and the shear rate, from which it can be seen that there was a period of rapid decrease in the apparent viscosity of the sample in the shear rate from 0 to 5 s\({}^{-1}\), while after the minimum viscosity, the slope of the viscosity curve increased continuously with further increase in the shear rate and then gradually leveled off, thus showing the shear-thickening behavior. This was due to the high solid content of the slurry and the tendency of the HCDA particles to aggregate into clusters, forming relatively large and compact polymer particles. The limited free water in the slurry could not completely wrap around the larger polymer particles, and its surface did not form a complete bonded water film, so at high shear rates, there was no water film lubrication of polymer particles colliding with each other more frequently, resulting in greater frictional resistance. The Herschel-Bulkley model is shown in Equation (1):  
\[\tau=\tau_{y}+K\dot{\gamma}^{n} \tag{1}\]  
where \(\tau_{y}\) is the yield stress (Pa), \(K\) is the consistency coefficient (Pa\(\cdot\)s\({}^{n}\)), and \(n\) is the flow index, which is for characterizing the non-linear relationship between shear stress and shear rate [60]. When \(n=1\) for the Bingham model, it is a Newtonian fluid; when \(n>1\), it is a shear-thickening fluid; and when \(n<1\), it is a shear-thinning fluid. However, the H-B model cannot provide a direct formula for another important rheological parameter, plastic viscosity up. [PERSON] derived empirical formulas such as Equation (2) through experimental studies [61]. \[\mu_{p}=\frac{3K}{2+n}\dot{\gamma}_{max}^{n-1} \tag{2}\]  
where \(\dot{\gamma}_{max}\) is the maximum shear rate during rheological testing. Parameters such as the yield stress, consistency coefficient, and flow index of the slurry were determined from the descent curves of each hysteresis cycle and obtained by fitting the Herschel-Bulkley model, and then the plastic viscosity was calculated according to Equation (2). The results are shown in Table 3 and Figure 6.  
Table 3 and Figure 6a show that when the content of HDCA decreased, yield stress and plastic viscosity gradually decreased by up to 88% and 34.9%, respectively. This indicates that HCDA increased the yield stress of fresh DSPB.