## 3 Performance Prediction of a Cement-Chemically Inert Quartz Filler Binary Mixture
### Experimental Overview
#### 3.2.1 Calibration of Input Parameters of Quartz Powder-Portland Cement Binary Blends  
Using the 72 h isothermal hydration heat data of Portland cement (with a water-to-binder ratio of 0.5 and no quartz), we determined the hydration kinetic reaction parameters for Portland cement, as presented in Table 2.  
Additionally, using the parameters B, C, De0, and kr from the cement hydration model and the 72 h isothermal hydration heat data of the cement-quartz blends (with a water-to-binder ratio of 0.5 and 20% quartz), we determined the parameters for the nucleation effect of the chemically inert quartz filler during the boundary reaction period (nu1) and the diffusion period (nu2), as shown in Table 3. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**B** & **C** & **De0** & **Kr** \\
**(cm/h)** & **(cm/h)** & **(cm\({}^{2}\)/h)** & **(cm/h)** \\ \hline \(2\times 10^{-9}\) & 0.004 & 1.05 \(\times\) 10\({}^{-10}\) & 1.55 \(\times\) 10\({}^{-5}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Reaction parameters of the Portland cement hydration model. Figure 1: Evaluation results of properties of cement–quartz blends (w/b = 0.5, M1, M2, and M3). Figure 1a presents the calculated and experimental results for the hydration heat at a water-to-(cement + quartz) ratio of 0.5. Within the first 72 h, increasing the amount of chemically inert quartz filler from 10% to 20% does not result in a significant change in the hydration heat. This is primarily because the nucleation effect of the chemically inert quartz filler accelerates the cement hydration reaction and raises the hydration heat, offsetting the reduction caused by dilution. Furthermore, it is observed that in the later stages of the hydration reaction, the cumulative hydration heat decreases as the amount of chemically inert quartz filler increases. This reduction is mainly due to the dilution effect of the quartz filler. In other words, the nucleation effect of the quartz filler is more pronounced in the early stage of hydration, while the dilution effect becomes more significant in the later stage. 2.2 Evaluation Properties of Quartz Powder-Portland Cement Binary Blends with a Water/Binder Ratio of 0.5 (Water Availability Coefficient wr = 1.0)  
Figure 1b shows the calculated results for the cement reaction level. As the amount of chemically inert quartz filler increases, the reaction level of the cement also increases due to the acceleration of the hydration reaction caused by the nucleation and dilution effects. In Figure 1c,d, these two effects are separated: the solid line represents both the nucleation and the dilution effects, while the dashed line only accounts for the dilution effect. The difference between the two lines illustrates the nucleation effect. It is observed that for cement and concrete with a water-to-(cement + quartz) ratio of 0.5, the difference in the reaction level becomes more pronounced as the amount of chemically inert quartz filler increases from 10% to 20%. This indicates that the nucleation effect of the chemically inert quartz filler becomes more significant as its substitution rate increases. Figure 1e presents the calculated results for chemically combined water. As the amount of chemically inert quartz filler increases, the quantity of chemically combined water decreases, particularly in the later stages of curing (28 days). This is because the dilution effect of the quartz filler becomes the dominant factor in the later stages of hydration. Figure 1f shows the calculated results for portlandite, which follows a trend similar to that of chemically combined water. Performance Prediction of Chemically Inert Quartz Filler Concrete with a Water/(Cement + Quartz) Ratio of 0.2 (Water Availability Coefficient wr = 1.0)  
According to the performance prediction model for chemically inert quartz filler concrete with a water-to-(cement + quartz) ratio of 0.5, as discussed in the previous section, the water availability coefficient is set to 1. This assumes that all capillary water is available for the cement hydration reaction.