## 6 Results and Discussion
### Fresh Tests
#### 6.1.3 Squeezing Flow Test  
According to prior research [63; 85], the load-displacement curve schematic from the squeezing test comprises three stages, as depicted in Figure 9. Consequently, the assessment of various pastes in this study was conducted based on these three stages.  
Examining the Effect of w/b and SF  
Figure 10 shows the behavior of series 1 (Figure 10a) and series 2 (Figure 10b) pastes regarding the effect of the w/b ratio. According to Figure 10a, the analysis of the behavior of the pastes during the squeezing flow test reveals that all pastes exhibit three stages (elastic  
Figure 9: Different stages of the load–displacement curve under the squeezing test.  
deformation, plastic deformation, and strain hardening). Pastes with higher w/b ratios are positioned lower than others, thus necessitating less compression load. Examining pastes with higher w/b ratios reveals a broader plastic stage. Conversely, pastes with lower w/b ratios (0.18) exhibit a shorter stage II due to drier conditions, advancing to stage III more quickly. Increasing the amount of water in the paste increases the likelihood of the dilatancy effect and results in a broader plastic phase [63; 86; 87; 88]. Additionally, the higher water content in the paste reduces fluid viscosity, impacting the interaction between superplasticizer particles and plate gaps. Pastes with higher w/b ratios have a shorter I phase, while pastes with lower w/b ratios exhibit a more pronounced I phase. Additionally, increased water content in the paste reduces the likelihood of experiencing stage III.  
According to Figure 10b, in series 2, pastes with higher water content have a broader stage II and a shorter elastic stage. Pastes with a w/b ratio of 0.18 exhibit all three stages but with a shorter plastic stage. Pastes with higher water content exhibit partial strain hardening in a small portion of their plastic behavior.  
A comparison between Figure 10a,b shows that the inclusion of SF in cement paste results in a more consistent behavior and enhances flowability, thereby lowering the need for compression force.  
Examining the Effect of SNF and SF  
Figure 11 illustrates the behavior of series 1 (Figure 11a) and 2 (Figure 11b) pastes concerning the impact of SNF dosage. Based on Figure 11a, the analysis of pastes shows that nearly all of them exhibit three stages. Lowering the SNF dosage appears to raise the necessary compression load. Pastes with a higher SNF dosage lead to greater displacement. The plastic stage (stage II) is broader in pastes with higher SNF doses. Conversely, pastes with a lower SNF dose exhibit a distinct stage I. An increase in SNF results in higher liquidity levels. The likelihood of encountering stage III decreases as the SNF dosage increases.  
Based on Figure 11b, pastes with dosages below SNF undergo all three stages, but the elastic stage is not visible in pastes with dosages of 0.8% or 0.9%. Additionally, pastes with SNF dosage require more compression force and enter the hardening stage earlier than other pastes. Mixtures with higher SNF dosages show a broader plastic paste.  
Figure 10: Load–displacement curves for the squeeze flow test—checking the effect of w/b: (a) series 1; (b) series 2.  
Comparing Figure (a)a,b reveals that the rise in SF results in the relocation of the paste curves to a lower position. Essentially, the presence of SF in cement paste enhances fluidity, reducing the required compression force to reach the objective. In summary, the enhanced performance of series 2 (with 20% SF) stems from optimized microstructural packing, controlled water distribution, stronger early cohesion, and reduced internal friction, all of which contribute to more uniform flow behavior and lower compression requirements across varying SNF and w/b ratio conditions.