## 4 Results
### Micro-Mechanical Analysis
#### 4.3.2 XRD Analysis of Single Early-Age Strength Component Cement Paste  
The net cement paste samples were prepared following the mix ratio in Table 3, were then cured for 7 days, and then tested by XRD. The experimental results are shown in Figure 5.  
As shown in Figure 5, the strongest diffraction peaks of Ca(OH)\({}_{2}\) (d = 0.49170 nm, 20 = 18.026\({}^{\circ}\)) in II-B1 and II-B2 with early-strength components added are significantly lower than that of the I-A benchmark group. Therefore, it can be speculated that early-age strength components II-B1 and II-B2 could consume Ca(OH)\({}_{2}\) in the cement paste, shorten the hydration induction period and speed up the cement hydration procedure. It can also be seen that the diffraction intensity of the main mineral phases of cement hydration (C\({}_{3}\)S, C\({}_{2}\)S) (d = 0.30672 nm, 20 = 29.089\({}^{\circ}\)) is lower than that of the reference group. This is due to \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Group**} & \multirow{2}{*}{**Porosity/\%**} & **Average Pore Size/nm** & **10–50 nm** & **>50 nm** \\  & & **Size/nm** & **Aperture Ratio** & **Aperture Ratio** \\ \hline I-A & 29.56 & 21.02 & 41.19 & 44.67 \\ II-B1 & 32.54 & 21.71 & 44.26 & 35.07 \\ II-B2 & 31.17 & 19.03 & 51.14 & 32.86 \\ II-B3 & 30.52 & 17.12 & 67.37 & 12.06 \\ III-C1 & 28.79 & 18.65 & 64.01 & 19.85 \\ III-C2 & 27.86 & 15.17 & 70.06 & 10.45 \\ III-C3 & 29.34 & 17.79 & 68.95 & 12.53 \\ III-C4 & 36.41 & 25.44 & 32.53 & 52.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Effect of composite premature strength inner sample guard material. Figure 4: Effect of composite premature strength internal maintenance material on 7-day pore size distribution of pure cement paste: (**a**) single early-age strength component; (**b**) compound early-age strength components. the decrease in Ca\({}^{2+}\) concentration in the region. The ion concentration difference of the C\({}_{3}\)S hydration inclusions increased, and the osmotic pressure increased as well [28], which resulted in the rupture of hydration inclusions, thus accelerating the hydration of the main mineral phases of cement hydration (C\({}_{3}\)S, C\({}_{2}\)S). The early-strength component of the II-B2 was calcium nitrite, which is a kind of inorganic salt. It could promote the generation of the cement hydration product Ca(OH)\({}_{2}\), thus speeding up the cement hydration process. Thus, the intensity of the Ca(OH)\({}_{2}\) diffraction peak in II-B2 did not decrease significantly compared with that of the reference group. The diffraction peak intensities of the main hydration products can be derived from the MDI Jade analysis, as shown in Table 5.  
From Table 5, it can be seen that the intensity of the Ca(OH)\({}_{2}\) diffraction peaks in group II-B1 and group II-B3 decreased by 54.11% and 56.64%, respectively, compared with the reference group. The early-age strength component alkanolamine-A in group II-B1 consisted of alcohol-amine groups, which could form water-soluble complexes with the metal cations in the cement paste [11]. It promoted aluminate phase hydration, thus increasing the early-age strength of the cement paste. The early-age strength of group II-B3 doped with alkanolamine-B is a mechanism that promotes hydrolysis and scattering of the refractory ferrates to achieve early-age strength [29]. The early-age strength component alkanolamine-B in group II-B3 could promote hydrolysis and the scattering of the refractory ferrates to achieve early-age strength. The intensity of the Ca(OH)\({}_{2}\) diffraction peak in group II-B2 was higher than that in the reference group. It can be seen from Table 5 that adding early-age strength components could significantly reduce the intensity of the main minerals (C\({}_{2}\)S, C\({}_{3}\)S), compared to that of the benchmark group. Thus, it can be concluded that although the mechanisms for different early-age strength components are different, they all speed up the hydration of the cement and promote the generation of cement hydration products.